CA1122014A - Production of explosive emulsions - Google Patents
Production of explosive emulsionsInfo
- Publication number
- CA1122014A CA1122014A CA000315956A CA315956A CA1122014A CA 1122014 A CA1122014 A CA 1122014A CA 000315956 A CA000315956 A CA 000315956A CA 315956 A CA315956 A CA 315956A CA 1122014 A CA1122014 A CA 1122014A
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- hydrocarbon fuel
- solution
- emulsion
- tank
- emulsion matrix
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Abstract
?7465 PRODUCTION OF EXPLOSIVE EMULSIONS
ABSTRACT
A process and-apparatus for preparing cap sensitive water-in-oil explosive emulsion compositions on a commercial basis is provided which includes mixing a hydrocarbon fuel component, an emulsifier, and an aqueous inorganic oxidizing salt solution under mixing conditions sufficient to obtain an emulsion matrix composition and thereafter blending microbubbles with the emulsion matrix, the microbubbles being introduced to the emulsion matrix from a deaerated reservoir thereof.
ABSTRACT
A process and-apparatus for preparing cap sensitive water-in-oil explosive emulsion compositions on a commercial basis is provided which includes mixing a hydrocarbon fuel component, an emulsifier, and an aqueous inorganic oxidizing salt solution under mixing conditions sufficient to obtain an emulsion matrix composition and thereafter blending microbubbles with the emulsion matrix, the microbubbles being introduced to the emulsion matrix from a deaerated reservoir thereof.
Description
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'BACKG~OUND OF TEIE INVENTION
! . In one aspect, the present invention relates to a ,process for preparing water-in-oil explosive emulsion composi-itions. In another aspect, the present invention relates to ~!apparatus for the continuous production of cap sensitive or ~blasting agent water-in-oil explosive emulsion compositions on the ~commercial level. In still a further aspectr the present invention relates to a process for manufacturing explosive l¦emulsion compositions including safety and quality control 11 ,,features further described hereinbelow.
~i Emulsion explosive compositions have recently obtained 'wide acceptance in the explosive industry because of their ~excellent explosive properties and ease of use in various applica-~
I~tions. Until recently, water-in-oil explosives ~enerally ¦comprised blasting agents requiring a booster in order to effect 'their detonation. These emulsion type blasting agents were first ¦
~disclosed by ~luhm in U.S. Patent No. 3,447,97~. While such emulsion type blasting agents have many advantages over other l'water slurry type blasting agents they are not cap sensitive. capl `20 ` isensitive emulsion explosives have been prepared in the past by the addition of an explosive ingredient or a specific detonation !~ catalyst. Examples of these types of cap sensitive emulsion 'ieXplosives are described in U.S. Reissue Patent No. 2~,060, U~S.
¦~Patent No. 3,770,522 and U.S. Patent No. 3,765,964.
1I Recently it has been discovered that a cap sensitive water-in-oil emlusion explosive composition, which can be detonated with a No. 6 cap at diameters of 1.25" and lower, which i,, ' .
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~1~21)14 does not contain an explosive ingredient or a detonakion cata-lyst can be formulated by employing closed cell void contain-ing materials, such as microbubbles fabricated from saran or glass, with specific proportions of a hydrocarbon fuel compon-ent, an emulsifier, water, inorganic oxidizing salts, and optionally, an auxiliary fuel, such as aluminum. These cap - sensitive water-in-oil explosive compositions are described in detail in U.S. Patent No. 4,110,134 which issued to C.G. Wade on August 29, 1978.
Processes for preparing occluded air sensltized water-in-oil emulsion blasting agents, which are noneap sensi-tive, as well as cap sensitive eompositions are known in the prior art. Such processes have a limited disadvantage in that because the products depend on occluded air for sensiti-zation, process conditions when admixing the aqueous oxidiz-ing salt solutions thereof with the hydrocarbon fuel eompon-ent thereof must be closely controlled. Temperature eonditions within such processes must be regulated such that the aqueous oxidizing salt solution does not reaeh a temperature so low so as to eause crystallization and salting out of the inorgan-ie oxidizing salts in the solution. However, the proeess must be operated at temperatures low enough sueh that the hydroearbon fuel eomponents, employed as the oil phase of the water-in-oil emulsion, are suffieiently eongealed so as to provide for oeelusion of air therein.
; The proeess for preparation of water-in-oil emul-sion explosive eompositions whieh are eap sensitive sueh as those deseribed above in U.S. Patent No. 4,110,134 does not require that the hydroearbon fuel eomponent be at ~1~2~)14 a congealing temperature since these explosive emulsion compositions do not reply upon occluded air for sensi-tization. ~lowever, water-in-oil explosive compositions which are cap sensitive present a higher hazard, from a production standpoint, since the increased sensitivity increases the risk of inadvertent detonation of the compositions during processing..
Therefore, a relatively sai-e and efficient method for producing cap sensitive water-in-oil explosive emulsions on a commercial scale is desirable and such a process presents problems of a different nature than those over-come by prior art processes dealing with the production of occluded air sensitized emulsion explosive compositions.
SU~IARY OF THE INVENTION
In accordance with one aspect of the invention there is provided a process for producing explosive emulsion compositions sensitized with microbubbles com~rlsing: (a) forming an aqueous inorganic oxidizing salt solution of at - least about 64% by weight inorganic oxidizing salts and maintaining said solution above the crystallization temper-ature thereof;~b) forming a hydrocarbon fuel component and heating it to approximately the same temperature as said oxidizing solution; (c) introducing said oxidizer solution, said hydrocarbon fuel component, and an emulsifier to a : 25 mixing zone and mixing at conditions sufficient to obtain emulsifying shear rates to thereby form an emulsion matrix, said emulsifier being added in a manner such that the time of contact with the heated oxidizer solution and hydro-carbon fuel component is not sufficient to cause said B
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'BACKG~OUND OF TEIE INVENTION
! . In one aspect, the present invention relates to a ,process for preparing water-in-oil explosive emulsion composi-itions. In another aspect, the present invention relates to ~!apparatus for the continuous production of cap sensitive or ~blasting agent water-in-oil explosive emulsion compositions on the ~commercial level. In still a further aspectr the present invention relates to a process for manufacturing explosive l¦emulsion compositions including safety and quality control 11 ,,features further described hereinbelow.
~i Emulsion explosive compositions have recently obtained 'wide acceptance in the explosive industry because of their ~excellent explosive properties and ease of use in various applica-~
I~tions. Until recently, water-in-oil explosives ~enerally ¦comprised blasting agents requiring a booster in order to effect 'their detonation. These emulsion type blasting agents were first ¦
~disclosed by ~luhm in U.S. Patent No. 3,447,97~. While such emulsion type blasting agents have many advantages over other l'water slurry type blasting agents they are not cap sensitive. capl `20 ` isensitive emulsion explosives have been prepared in the past by the addition of an explosive ingredient or a specific detonation !~ catalyst. Examples of these types of cap sensitive emulsion 'ieXplosives are described in U.S. Reissue Patent No. 2~,060, U~S.
¦~Patent No. 3,770,522 and U.S. Patent No. 3,765,964.
1I Recently it has been discovered that a cap sensitive water-in-oil emlusion explosive composition, which can be detonated with a No. 6 cap at diameters of 1.25" and lower, which i,, ' .
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~1~21)14 does not contain an explosive ingredient or a detonakion cata-lyst can be formulated by employing closed cell void contain-ing materials, such as microbubbles fabricated from saran or glass, with specific proportions of a hydrocarbon fuel compon-ent, an emulsifier, water, inorganic oxidizing salts, and optionally, an auxiliary fuel, such as aluminum. These cap - sensitive water-in-oil explosive compositions are described in detail in U.S. Patent No. 4,110,134 which issued to C.G. Wade on August 29, 1978.
Processes for preparing occluded air sensltized water-in-oil emulsion blasting agents, which are noneap sensi-tive, as well as cap sensitive eompositions are known in the prior art. Such processes have a limited disadvantage in that because the products depend on occluded air for sensiti-zation, process conditions when admixing the aqueous oxidiz-ing salt solutions thereof with the hydrocarbon fuel eompon-ent thereof must be closely controlled. Temperature eonditions within such processes must be regulated such that the aqueous oxidizing salt solution does not reaeh a temperature so low so as to eause crystallization and salting out of the inorgan-ie oxidizing salts in the solution. However, the proeess must be operated at temperatures low enough sueh that the hydroearbon fuel eomponents, employed as the oil phase of the water-in-oil emulsion, are suffieiently eongealed so as to provide for oeelusion of air therein.
; The proeess for preparation of water-in-oil emul-sion explosive eompositions whieh are eap sensitive sueh as those deseribed above in U.S. Patent No. 4,110,134 does not require that the hydroearbon fuel eomponent be at ~1~2~)14 a congealing temperature since these explosive emulsion compositions do not reply upon occluded air for sensi-tization. ~lowever, water-in-oil explosive compositions which are cap sensitive present a higher hazard, from a production standpoint, since the increased sensitivity increases the risk of inadvertent detonation of the compositions during processing..
Therefore, a relatively sai-e and efficient method for producing cap sensitive water-in-oil explosive emulsions on a commercial scale is desirable and such a process presents problems of a different nature than those over-come by prior art processes dealing with the production of occluded air sensitized emulsion explosive compositions.
SU~IARY OF THE INVENTION
In accordance with one aspect of the invention there is provided a process for producing explosive emulsion compositions sensitized with microbubbles com~rlsing: (a) forming an aqueous inorganic oxidizing salt solution of at - least about 64% by weight inorganic oxidizing salts and maintaining said solution above the crystallization temper-ature thereof;~b) forming a hydrocarbon fuel component and heating it to approximately the same temperature as said oxidizing solution; (c) introducing said oxidizer solution, said hydrocarbon fuel component, and an emulsifier to a : 25 mixing zone and mixing at conditions sufficient to obtain emulsifying shear rates to thereby form an emulsion matrix, said emulsifier being added in a manner such that the time of contact with the heated oxidizer solution and hydro-carbon fuel component is not sufficient to cause said B
2~14 emu].sifier to degrade prior to the formation of said emulsion matrix; and (d) blending with said emulsion matrix a predetermined quantity of microbubbles delivered from a deaerated supply thereof to form explosive emulsion.
In accordance with another aspect of the invention there is provided a system for ~producing water-in-oil explosive compositions on a continuous basis comprising:
(a) an aqueous oxidizer solution production line com-prising:(i) inlet conduit and pumping means for delivery of inorganic oxidizing salts and water to an oxidizer solution makeup tank said tank having~load cell means interconnected with said input pumping means for auto-matically stopping the delivery of aqueous oxidizer salt solutions thereto once a predetermined quantity has been deposited therein, (ii) heating means for maintaining the oxidizing solution delivered to said oxidizer solution makeup tank at a temperature above the crystallization point of said solution~ (iii) filter means for filtering the aqueous oxidizer solution delivered from said tank, and (iv) outlet conduit and metering pump means for delivering said oxidizing solution from said tank at : preselected flow rates; (b) a hydrocarbon fuel component production line comprising: (i) inlet conduit and pumping means for delivery of hydrocarbon fuel components to a hydrocarbon fuel makeup tank said tank having load cell means interconnected with said input pumping means for automatically stopping delivery of hydrocarbon fuel thereto once a predetermined quantity has been deposited therein, (ii) heating means for heating said hydrocarbon - 4a -~ .
3L1~2014 fuel to approximately the same temperature at which said oxidizer solution is maintained, (iii) filter means for filtering said hydrocarbon fuel delivered from said hydro-carbon fuel tank, and tiV) outlet conduit and metering.
pump means for delivering hydrocarbon fuel from said hydrocarbon fuel tank at preselected flow rates; (c) an emulsion matrix processing line for forming an emulsion matrix from the hydrocarbon fuel delivered by said hydro-carbon fuel production line and said oxidizer solution delivered by said oxidier solution production line and processing said emulsion matrix into~emulsion explosive compositions comprising: (i) mixing means having an inlet connected to the outlet conduits of said aqueous oxidizer solution production line and said hydrocarbon fuel production line and an outlet; (ii) blender means connected to the outlet of said mixing means for blending sensitizing agents with said emulsion matrix to form said water-in-oil emulsion explosive compositions; (iii) flexible conduit detonation trap means interconnected between said mixer and said blender for containing any conflagration initiated in said mixer and thereby preventing said conflagration from detonating the water-in-oil explosive emulsion composition formed in said blender; and (d) an emulsifier holding tank connected to a delivery conduit and metering pump means for delivering said emulsifier to said mixing means said delivery conduit entering the system at a point such that said emulsifier will not degrade from contact with the heated oxidizer solution or hydrocarbon fuel prior to formation of the emulsion mat:rix.
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According to the invention, an improved method for the production of water-in-oil explosive compositions which can be detonated with a No. 6 cap at diameters of 1.25" and lower and which do not contain an explosive ingredient or detonation catalyst is provided. These explosive emulsion compositions as well as microbubble containing noncap-sensi-tive water-in-oil emulsion blasting agents can be prepared as described below. The process and apparatus described herein is capable of producing such explosive compositions on a commercial basis in a manner providing for strict control of product quality and optimum safety during processing.
Basically, the process of the subject invention includes forming two premixes, one comprising an aqueous solution of inorganic oxidizing salts, and the' second compris-ing hydrocarbon fuel components, which provide the oil phase of the water-in-oil emulsion explosive composition, and mix-ing, on a continuous basis, these two premixes with an appro-priate amount of an emulsifier to form an emulsion matrix composition. The aqueous solution of oxidizing salts is heated to a temperature above the crystallization point of the solution and is maintained at that temperature, usually about 185 degrees F or greater, until the emulsion matrix is formed. The hydrocarbon fuel components are also heated to approximately the same temperature so as to avoid a rapid temperature drop upon admixture with the aqueous oxidizer solution. The emulsifier is added to the system in a manner such that the heat of the fuel and oxidizer solution does no_ cause it to degrade , j~r Z~l~
B7465 1l !! prior to formation oE the emulsion matrix. The emulsion matrix is ¦ formed by subjecting the hydrocarbon fuel component, the aqueous ! solution of inorganic oxidizing salts and the emulsifier to mixing l conditions sufficient to obtain emulsifying shear rates within the ¦`mixer. The term "emulsifying shear rates" as employed herein is ! defined to mean shear conditions at least equal to those obtained when the above-described components are mixed in a continuous ¦¦recycle mixer (further described below) at pressures of from about l~10 to about ~0 psig and preferable of from about 35 to about 40 Ipsig, residence times of about 4.5 seconds, and typical impeller ¦!speeds of at least about 1400 rpm (based on the use of a continuouc ¦Irecycle mixer having a 6" i~peller diameter). The emulsion matrix ¦Iprepared in this manner is fed on a continuous basis to a paddle ¦¦or ribbon type continuous blender where glass or resin jimicrobubbles, and, if desired, an auxiliary fuel such as particulate aluminum, are blended therewith to form the cap ~sensitive water-in-oil explosive compositions. Noncap-sensitive ¦jexplosive emulsions can also be produced by varying the Ilcomposition of the explosive emulsion such as, for example, Illowering the amount of microbubbles employed. It has been ¦laiscovered that in order to obtain products of uniform composition ¦ithe microbubbles must be fed to the continuous blender from a ¦ireservoir thereof containing a quantity of deaerated microbubbles.
iAs further described below, microballoons because of their ~25 j'peculiar shape, low density and flow characteristics are difficult ~to measure and add in a predetermined fashion if the microbubbles ~have been mixed with the normal amount of air which will come in ¦'contact therewith during handling and delivery to the blender.
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~ i B7~65 , The above process can be conveniently carried out on a commercial scale by employing an oxidizing solution production 'line for forming, filtering and metering the oxidizer solution to the continuous recycle mixer (or equivalent mixers), and a hydrocarbon fuel production line for similarly handling the oil phase of the water-in-oil emulsion explosive. After admixture of ,the two premixes to form an emulsion matrix, an emulsion matrix ,processing line can be employed to obtain the cap sensitive ~explosive compositions ready for packaging.
o i! Another aspect of the present invention involves the use ~~of a detonation trap located between the continuous recycle mixer t~which forms the emulsion matrix composition and the blender ,wherein microbubbles and particulate aluminum are blended with the ',emulsion matrix to produce the cap sensitive emulsion composi-~tions. ~asically, the detonation trap comprises a piece of ~,flexible conduit located between the mixer and the blender such I!
',that any conflagration which may be initiated in the mixer will 'not be transmitted to the cap sensitive materials being produced ~`in the blender down stream thereof.
" Various other functions and advantages of the process ; ~~and apparatus of the present invention will be apparent from a ,study of the drawing which depicts a schematic representation of ' ,one embodiment of the process of the present invention as well as ~from a study of the detailed descrlption contained hereinbelow.
'1', - 1 '; 7 ~1 ~ r l~Z~ 1 4 1~ ' B7~165 l ~DETAILED DESCRIPTION OF THE INVENTION
Now referring to the drawing a pre~erred embodiment of the process of the subject invention will be described in relation thereto. The aqueous solution of inorganic oxidizing salts will ~contain at least 64% by weight inorganic oxidizing salts selected ~from the group consisting of ammonium nitrate, alkali and alkaline earth metal nitrates and perchlorates. Normally ammonium nitrate ¦ will comprise at least about 53% by weight of the solution. The l aqueous solution of inorganic oxidizing salts can be prepared in ¦ a production line manner as follows. A reservoir tank 2 of an aqueous ammonium nitrate solution comprising from about 80% to labout 97~ by weight of ammonium nitrate and preferably about 93%
¦by weight of ammonium nitrate is kept heated (above the saturation I 1temPerature) at temperatures of from about 180 degrees F to about 290 degrees F by appropriate heat supplying means such as steam ~coils 4. Normally it is desirable to maintain temperatures ¦high enough throughout the system so that crystallization of the concentrated inorganic oxidizing salts in the aqueous solution ¦is prevented. The ammonium nitrate solution is pumped by an ¦outlet conduit 5 through pumping means 6 to oxidizer makeup tank l0 via conduits 8 and 9. An aqueous solution of sodium I ¦ perchlorate can also be added to oxidizer makeup tank l0 via conduits 14 and 9 and pumping means 16. Since the sodium ¦ perchlorate solution concentrations required are not usually ¦ commercially ava;lable, a sodium perchlorate makeup tank 18 can be provided with suitable agitation means 20 which can comprise a stirrer and electric drive means, and a heat supply such as steam coils 22. The sodium perchlorate solution can be pumped via I
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B7465 ,, outlet conduit 24 and pumping means 16 into the oxidizer makeup tank 10 as described above. Sodium perchlorate recycle conduit ' 26 can be employed to recycle excess portions of sodium perchlorate solution back to sodium perchlorate makeup tank ~ 5 ,18 and thereby provide additional agitation. In addition, solid ; sodium nitrate may be added to oxidizer makeup tank 10 either ! manually or via conduits 28 and 9 from sodium nitrate holding bin 1! 31 by any number of conventional solid feed conveying means, such !l as screw conveyors and the like. If water is necessary in order jlto adjust the concentration of the inorganic oxidizing salt solution, water conduit 30 can supply same in a controlled manner via water metering means 32.
I~ Load cells 12, upon which oxidizing makeup tank 10 ,rests, automatically sense, by weight, the amount of oxidizin~
! salt solution present in oxidizer makeup tank 10 and automatically provide for shutdown of the pumping means 6 and 16 connected thereto when the predetermined amount of oxidizer solutlon has been deposited in makeup tank 10. Load cells 12 can also be i'employed to control the flow of solid ammonium nitrate. Oxidizer ~makeup tank agitation means 34 insures that a homogeneous solution ¦of the various inorganic oxidizing salts is prepared in oxidizer ,makeup tank 10. Heating means such as steam coils 36 are employed in order to keep the inorganic oxidizing solution at approximately jl90 degrees F, or above the crystallization temperature of the !particular oxidizing salt solution. The temperatures in the ¦,ammonium nitrate solution holding tank 2, the sodium perchlorate makeup tank 18, and the oxidizer solution makeup tank 10 can be , _ g _ ~ ?14 B7465 !
controlled by providing a number of automatic temperature recording and control means (TRC) depicted schematically in the drawing.
I The inorganic oxidizing salt solution is pumped from lioxidizer ma~eup tank 10 via outlet conduit 38, pumping means 40 and conduit 42, where filter means 4~, which can comprise screen or fabric type filtering devices, removes any particulate ¦contaminates and inorganic oxidizing salts which have failed to jgo into solution. The filtered inorganic oxidizing solution is ¦then delivered by conduit 46 to oxidizer holding tank 48 which is preferably of a slightly larger capacity than oxidiæer makeup tank ¦10. Oxidizer holding tank 48 is also supplied with a~itation ¦means 50 and steam coils 52. If necessary, water can be added to ¦the oxidizer holding tank 48 via water meter 54 and water conduit ¦ 56. On the other hand, it may be necessary to lower the water content of the aqueous oxidizer solution in order to increase the concentration of inorganic oxidizing salts, and in this case heat ~can be supplied by steam coils 52 in order to cause evaporation ~of water from oxidizer holding tank 48.
¦ Oxidizer solution pumping means 58 is preferably a highly accurate metering type pump preferably of the positive ¦displacement diaphragm type. Such pumps are capable of metering ¦rates of flow therethrough at tolerances of about + 1%. Suitable ¦such pumps are sold by Milton Roy Inc., Philadelphia, Pa.
¦under the trade designation MILROYAL. -~Z~14 .
B7~65 Dual filtering means 60a and 60b provide for a second filtration of the inorganic oxidizing salt solution as it leaves the metering pump means 58. Use of dual filters provides for reduced load on each filter and increased operation time between filter cleansing operations. Further~ore pumping can continue through one filter while the other is being-cleaned, thus avoiding ,shutdown of the process. An accumulator 62 is provided, including ; ,'pressurized air source 64 and pressure measurement means ~6 for the purpose of damping the oscillating pressure pulses which issue -Ifrom positive displacement diaphragm type metering pump 58. The loxidizing solution travels through feed line 68, which can be 'jsurrounded by a hot water jacket 70 supplied with stea~ or water l~at a temperature sufficient to keep the inorganic oxidizing solution above its crystallization temperature (about 190 degrees ~15 ~F). Metering means 72 provides for accurate measurement of the ~flow of the inorganic oxidizing solution through conduit 68 and ~rPlief valve 74 provides for the release of over pressure or any 'excess amounts of inorganic oxidizins solution from the system via j'drain conduit 76. Rupture disc 78 provides for emergency release ,of excess flow rates of the inorganic oxidizing salt solution.
One-way valve 80 insures that none of the hydrocarbon fuel phase (to be described below) backs up into the oxidizer solution portion of the system and thereby contaminating it. The junction lof inorganic oxidizing solution feed line 68 with hydrocarbon fuel 'lcomponent conduit 82 provides for the delivery of the two ,components to continuous recycle mixer 168 (described below) or ; lits equivalent.
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.1 i B7465 ~) The preparation of the hydrocarbon fuel phase of the water-in-oil explosive compositions produced by the process of the subject invention will now be described with relation to the - ¦
drasYing. The f~el component can also be produced in a production line manner so as to facilitate continuous production of the emulsion explosive compositions on a commercial scale. The carbonaceous fuel component which is useful in preparing such ~compositions includes most hydrocarbons, for example, paraffinic, olefinic, naphthenic, aromatic, saturated or unsaturated ,hydrocarbons. In general, the carbonaceous fuel is a water limmiscible, emulsifiable fuel which is either liquid or ¦!liquefiable at a temperature up to about 200 degrees F, and jpreferably between about 110 degrees F and 160 degrees F. It is - ,, .
'preferable that the carbonaceous fuel include a combination of a lwax and an oil. However, waxes are not always necessary.
Suitable oils which can be used in the process of the subject iinvention include petroleum oils, various vegetable oils and 'various grades of dinitrotoluene; a highly refined mineral oil sold by Atlantic Refining Company under the trade designation , ATREOL; a white mineral oil sold under the trade designation ~RAYDOL by Witco Chemical Company, Inc., and the like. Thus, oil 'holding tank 84 provides a supply of oil to the system via conduit i86 and oil pumping means 88. Oil is p~mped via conduit 90 to fuel ~ llmakeup tank 92. Normally, the oil component of the carbonaceous -`25 ,Ifuel can be pumped at ambient temperatures without the necessity ~for heating the equipment.
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B7465 1l As noted above, in a pr~ferred embodiment of the subject invention a mixture of oils and waxes is~employed. ,S~uitable waxes ~which can he employed hav~e melting points of at least 80 degrees F
llpreferably in the range of about ll0 to about 200 degrees F.
liExamp1es o,f s~uitable waxes incl~de waxes derived from petroleum, ¦is~uch as petrolatum wax, microcrystalline wax, and paraEfin wax, ~mineral waxes such as ozo~erite and montan wax, animal waxes such !¦as spermacetic wax, and insect waxes such as beeswax and Chinese ¦¦wax~. !Preferred waxes include those identified by the trade 1ldesignations INDRA 11~3, INDRA 5055-G, .INDRA 4350-E, ,INDRA 2126-E
¦and .INDRA 2119 sold by Industrial Raw Materials Corporation, and a similar wax sold by Mobil Oil Corporation under the trade ¦designation MOBIL 150 as well as WITCO X145-A sold by Witco !Chemical Company Inc., and ARISTO 143 sold by Union 76 Co. These waxes can be charged manually, or by automatic conveyor means, to ¦wax melt tank 94, which is supplied with heating means such as steam coils 96, and agitation means 98, to thereby melt the wax and allow it to be pumped via outlet conduit 100, and wax pumping 'means 102, through conduit 104 to fuel makeup tank 92. Fuel Imakeup tank 92 is also supplied with heating means such as steam ¦~coils 106 so as to maintain the temperature of the oil-wax mixture ¦above its cQngealing point. Agitatlng means 108 is provided so as Ito insure a good mix between oil and wax components. Load cells ~10 are used to automatically control the oil pumping means 88 and ¦wax pumping means 102, these pumping means being automatically Ishut down when a predetermined weight of fuel components have been ¦Idelivere~l to iuel makeup tank 92. Fuel outlet conduit 112 and z~
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B7465 ¦~
'pumping rneans 114 deliver the fuel component via conduit 116 to fuel holding tank 118 which is also supplied with agitation means ¦
120 and heating means such as steam coils 122. The heating means ¦
,described above are employed to raise the temperature of the hydrocarbon fuel component to approximately the same temperature ~as the oxidizing solution described above. Thus when the fuel and .,oxidizer components are mixed together there will be no cooling off of the oxidizer solution which misht result in undesirable licrystallization of the inorganic oxidizing salts. Fuel holding ¦¦tank 118 insures that a ready supply of hydrocarbon fuel component ~,(the oil and wax mixture) of the explosive compositions prepared iby the process of the subject invention are ready on a continuoùs ~basis for use in the process. E~ydrocarbon fuel line 124 delivers I,the hydrocarbon fuel component to the inlet of a metering fuel I'pump means 126 which is preferably of the positive displacement ,diaphragm type described above. Accumulator 128, or an equivalent jpulse dampening device, pressure sensing means 13Q and an air pressure source provide means for damping the pulsating flow of l,hydrocarbon fuel component through fuel conduit 134 to melt filter ll136. Filtered hydrocarbon fuel component ~separated from any - jlcongealed solid fuel by the filter) is delivered via conduit 138 - which is provided with heating jacket 140. ~letering means 142 '~provides for the controlled flow of the hydrocarbon fuel component ¦Ithrough line 82 where it contacts the aqueous inorganic oxidizing l,salt solution at the intersection of conduits 68 and 82. Between tmetering means 1~2 and the intersection of conduits 68 and 82, ¦,relief valve means 144 is provided for bleeding off any excess i - 14 -., .
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fuel component pressure delivered through meter 1~2, and rupture ¦.disc means 146 is provided for emergency relief of unexpected excesses flowing through line 82. One-way valve means 148 l'protects the fuel component line from contamination should a ',backup occur causing the inorganic oxidizing salt solution to flow back up conduit 82.
A suitable emulsifier used to form the emulsion matrix ,,from the aqueous inorganic oxidizing solution and the hydrocarbon ; I,fuel components described hereinabove is supplied via emulsifier l¦reserve tank 150 through conduit 152, pumping means 154, and conduit 156 to emulsifier holding tank 158. Emulsifiers useful in lithe preparation of water and oil explosive emulsions include those ¦iderivable from sorbitol by esterification with removal of one i,molecule of water such as sorbitan, fatty acid esters r for :lS ¦iexample, sorbitan monolaurate, sorbitan monooleate, sorbitan ~lmonopalmitate, sorbitan monostearate, and sorbitan tristearate.
; ¦,Other useful materials comprise mono- and diglycerides of ¦Ifat-forming fatty acids, as well as polyoxyethylene sorbitol ¦lesters, such as polyethylene sorbitol beeswax deriva~ive materials ~20 !and polyoxyethylene(4) lauryl ether, polyoxyethylene~2) ether, ¦.polyxyethylene (2) stearyl ether, polyoxyalkylene oleate, ,polyoxyalkylene oleyl acid phosphate, substituted oxazolines and phosphate esters and mixtures thereof and the like. Emulsifiers ,of this general type are delivered via outlet conduit 160 and 'metering pump means 162, which is preferably of the positive displacement diaphragm type described above, to emulsifier conduit ~64 which enters :euel component conduit 82 near the intersection - 15 - ~
., B7465 1l of conduits 82 and 68. It has been discovered that many of the ~emulsifiers use~ul in the emulsion explosive compositions of the ~present invention will tend to degrade with time if exposed to the relatively high processing temperatures of the present invention.
Therefore, it has been found to be especially preferable to introduce the emulsifier, at substantially ambient temperatures, ~at a point just prior to mixing oE the fuel component and ,~inorganic oxidizing salt solution to form an emulsion matrix. Of i~course, the emulsifier could be added directly to the mixer or ~could be added in conjunction with the inorganic oxidizing salt solution, however, it has been found to be preferred to allow the 'emulsifier to admix with the fuel component just prior to the ,admixing of these materials with the inorganic oxidizing salt 'solution.
~ The process step of admixing the fuel component with the 'inorganic oxidizing salt solution will now be described in detail ¦!with reference to the drawin~. As noted above, the emulsifier i.
preferably enters the fuel component conduit 82 at a point just prior to where conduit 82 joins oxidizing solution conduit 68.
~20 ~The mixture of the inorganic oxidizlng solution and fuel component ,can then be further processed in a single emulsion matrix processing line which basically comprises a continuous recycle ~ixer, for forming the emulsion matrix, and a blending apparatus I!for the addition of sensitizing agents, such as microbubbles, the ,mixer and blender being separated by a detonation trap for safety ¦,reasons described below. Thus, the oxidizer solution and fuel mixture is delivered via conduit 166 to a mixing means such as 1~ 4 , .
ill B7~65 ~continuous recycle mixer 168. Temperature sensing means 167 and 169, com~unicating with the inlet and outlet, respectively of continuous recycle mixer 168 provide for monitoring of process conditions within the mixer and can be used as warning devices should the mixer develop mechanica:L problems. Suitable continuous recycle mixers are available from Chemetron, Inc., sold under the trade na~e VOTATOR CR MIXER. Basically, a continuous recycle mixer provides for a constant residence time of materials therein I'but provides for continuous recycling of the materials over a ilseries of intermeshing pins so that the hydrocarbon fuel and ~'oxidizer solution are thoroughly mixed in the presence of the ,lemulsifier. Continuous recycle mixers accomplish this action by j¦means of a multi-vaned impeller sandwiched between two discs.
'Each of the discs have a series of pins thereon which mesh with jpins on the mixer housing. ~y providing apertures on the discs which cause material in the mixer to be recycled back through the intermeshing pins prior to passage out of the mixer, the recycle mixing action is accomplished. Such action within the mixer ,'provides for extremely good admixture of the fuel component with ,the inorganic oxidizing component and insures production of a stable emulsion. It has been discovered that operating such a ,Imixer, having an impeller of about 6" in diameter, at rotor speeds iof from about 1400 rpm and at pressures within the mixer of from ,about 35 to about 40 psig, with average residence times of about l~4.5 seconds, results in an extremely stable emulsion matrix useful in the production of cap sensitive water-in-oil explosive emulsion compositions. Of course various other operating parameters can , 1 l . ~
s7465 il I be employed, depending upon the particular size of the mixer and the amount of product being processed, but the emulsifying shear rate conditions must be maintained in order to obtain stable emulsions. ~hile continuous recycle mixers have been found to be excellent means for obtaining the recessory emulsifying shear rates other mixers which can be employed include in-line mixers such as those sold under the trade designation TUREON/ by Tobert ¦ Industries, Inc., Southbridge Mass. or colloid type mixers such l! as an OAKES mixer sold by E.T. Oakes Corp., Islip, N.Y.
ll The emulsion explosive matrïx formed in mixer 168 is ¦¦delivered via outlet conduit 170, through detonation trap 172 ¦~(described below), to pinch valve means 174. Pressure sensing ¦`means 176 is preferably automatically interconnected with pinch ~Ivalve means 174 to regulate the pressure in ~ixer 168 so that it lfalls within the ranges described above in order to produce the stable emulsion matrix within mixer 168. Furthermore, pressure ¦Isensing means 176 also provides for the monitoring of the emulsion matrix leaving mixer 168 via conduit 170 to insure that the i,mixture is emulsified to the desired extent. If the emulsion jshould "break", that is, if the aqueous oxidizer solution failed ¦¦to become emulsified into discrete globules contained within a ,continuous oil phase, the pumping characteristics of the matrix ¦flowing through outlet conduit 170 will change drastically causing Ija reduction in pressure sensed by pressure sensing means 176.
-25 i~,Thus, either throu~h manual inspection or by automatic means, pressure sensing means 176 will indicate that undesirable "broken"
m~ixtures of the aqueous oxidizer solution and the fuel components 1 . I
i - 18 -f~
I' ll B7465 !~
¦'are exiting from mixer 168. Appropriate remedial action can then i be taken manually, or automatically, to avoid conta~ination of ! down-line product, for example by controllin~ pinch valve 174.
,~ Detonation trap 17~ basically comprises a flexible S , conduit which has been discovered to prevent a conflagration initiating in the mixer 168 or conduit 170 from propagating there-through and reaching the continuous blender described below.
~Basically, the detonation trap 172 can be manufactured from any of a number of chemically inert elastomeric substances which are ¦~capable of withstanding the pressures and temperatures employed in the process, as well as the chemical action of the emulsion matrix !j passing therethrough. For example, in a process wherein the flow l~rate through conduit 170 is about 50 lbs./minute a flexible piece ; ¦!of tubing approximately 18" in length having an internal diameter ~15 l¦of 1-1/2" and manufactured from rubber, polyethylene or a ¦Icomposite of these and similar materials can be used as the j~detonation trap of the present invention. A typical hose used ~or ¦this purpose is sold under the trade designation FLEXWING by I,Goodyear Tire and Rubber Co. of Akron, Ohio which comprises a ! polyethylene tube and reinforced rubber cover with spiral wire ,helix between braided synthetic yarn.
¦I The emulsion matrix passes via pinch valve 174 into iconduit 178 and into continuous blender 180. Continuous blender ¦ilg0 provides for the admixture of the emulsion matrix with closed icell void containing materials such as glass or resin ¦microbubbles. Glass microbubbles are pre~erred. Particulate metal fuels, and the like, such as particalate aluminum, for ' .
Ii .
B~465 example, can also be added and thoroughly admixed with the ¦! emulsion matrix in continuous blender 180. Continuous blender 180 ¦'preferably comprises any of a number of continuous blenders of the ¦,paddle type such as those sold by Sprout Waldon Co., Day Mixing ilCQ. and Cleveland Mixer, Co., although other types of blenders, ~including ribbon type:blenders,,for example, can be employed.
The microbubbles are added to the system via vacuum line .182 which sucks microbubbles,from a storage barrel or other ~,container 184. This method of feed provides for minimizing the !dispersion o,f microbubbles in the air so as to avoid health hazards. Vacuum line 182 delivers the microbubbles to microballoon hopper 184. It has been discovered that because of the fine particulate nature of the microbubbles the flow Icharacteristics ~f a guantity thereof is highly dependent upon how `15 ¦I,long they have been allowed to settle after transportation via a Ivacuum source whereby air is intermixed therewith. Thus, ¦microbubbles which have been transported and admixed with air have ¦flow characteristics very similar to those of water and will pour, ~,at rates which are hard to control, into the feeder mechanisms for ¦,the:blender,180. This condition is very undesirable as close j~control of the amount of microbubbles being admixed with the emulsion matrix is critical if ~uality products are to be ~attained. Therefore, it has been discovered that microbubble hopper 184 should provide for a residence time of at least 4 ~25 'minutes to thereby allow the microbubbles to deaerate and become packed within the hopper~l84~ ,However, once the microbubbles ~deaerat a~d sett:Le withi~ the hopper, their flrw characteristic~
1~
~ ~ - 20 - ~
f Z~14 I!
B7465 l become similar to those of normal solid materials and flow out of ¦the hopper will not proceed at an even rate under gravitational ~force alone. Therefore, a screw feed mechanism 186, such as a l~.Soder prefeed screw mechanism sold ~y The KTron Corporation, can ¦:he employed to feed the microbubbles from hopper 184 to a ,weigh-helt type of,feed mechanism :l88. The screw feeder must be of the dual screw type having mesh:ing flights such -that the flow of the microbubbles therealong can be controlled. The weigh-belt l can be those sold under the trade name KTRON by RTron Corporation, ¦ Glasboro, N.J. ;The weigh-belt mechanism,188, in conjunction with the screw feed mechanism 186, can be employed to deliver a closely controlLed quantity of microbubbles to the continuous blender 180.
~The amount of microbubbles can be controlled either on the basis lo~f volume or on the basis of weight, as desired. This,feature is I.especially desirable since the density of a selected grade of ¦microb,ubbles may vary:widely. .For example microbubbles listed as having a density of "0.15/cc" may vary between about 0.12 and ¦Q~18 g/cc. Therefore, i,f the,final end product is desired to have a specified total weight percent of microoubbles, the weigh-belt ~20 ¦ Jfeed mechanism 188 can be employed to deliver a known quantity of miarobubbles to tne continuous blender 180 based on the flow rate ¦ of the emulsion matrix into mixer,l80 via conduit 178. On the other hand, if a controlled density product is desired, the screw ,~feed mechanism,l86 can be employed to provide for specific volumetric additions of microballoons to weigh feed belt feeder mechanism-188 (which in that case merely acts as a conveyor belt), and then to blender 180, to provide for the production of a product having kno.wn density characteristics.
1, B7465 1;
The finished water-in-oil explosive compositions exit blender 180 via er.it conduit 190, and screen 192 and are delivered to packaging apparatus where the emulsions can be packaged as desired, for example, in cardboard or paper cartridges, plastic bags and the like.
While this invention has been described in relation to .its preferred embodiments it is to be understood that various modifications thereof will now be apparent to one skilled in the 'art upon reading this specification and it is intended to cover i,all such modifications as fall within the scope of the appended ,Iclaims.
11i ~
~' .
In accordance with another aspect of the invention there is provided a system for ~producing water-in-oil explosive compositions on a continuous basis comprising:
(a) an aqueous oxidizer solution production line com-prising:(i) inlet conduit and pumping means for delivery of inorganic oxidizing salts and water to an oxidizer solution makeup tank said tank having~load cell means interconnected with said input pumping means for auto-matically stopping the delivery of aqueous oxidizer salt solutions thereto once a predetermined quantity has been deposited therein, (ii) heating means for maintaining the oxidizing solution delivered to said oxidizer solution makeup tank at a temperature above the crystallization point of said solution~ (iii) filter means for filtering the aqueous oxidizer solution delivered from said tank, and (iv) outlet conduit and metering pump means for delivering said oxidizing solution from said tank at : preselected flow rates; (b) a hydrocarbon fuel component production line comprising: (i) inlet conduit and pumping means for delivery of hydrocarbon fuel components to a hydrocarbon fuel makeup tank said tank having load cell means interconnected with said input pumping means for automatically stopping delivery of hydrocarbon fuel thereto once a predetermined quantity has been deposited therein, (ii) heating means for heating said hydrocarbon - 4a -~ .
3L1~2014 fuel to approximately the same temperature at which said oxidizer solution is maintained, (iii) filter means for filtering said hydrocarbon fuel delivered from said hydro-carbon fuel tank, and tiV) outlet conduit and metering.
pump means for delivering hydrocarbon fuel from said hydrocarbon fuel tank at preselected flow rates; (c) an emulsion matrix processing line for forming an emulsion matrix from the hydrocarbon fuel delivered by said hydro-carbon fuel production line and said oxidizer solution delivered by said oxidier solution production line and processing said emulsion matrix into~emulsion explosive compositions comprising: (i) mixing means having an inlet connected to the outlet conduits of said aqueous oxidizer solution production line and said hydrocarbon fuel production line and an outlet; (ii) blender means connected to the outlet of said mixing means for blending sensitizing agents with said emulsion matrix to form said water-in-oil emulsion explosive compositions; (iii) flexible conduit detonation trap means interconnected between said mixer and said blender for containing any conflagration initiated in said mixer and thereby preventing said conflagration from detonating the water-in-oil explosive emulsion composition formed in said blender; and (d) an emulsifier holding tank connected to a delivery conduit and metering pump means for delivering said emulsifier to said mixing means said delivery conduit entering the system at a point such that said emulsifier will not degrade from contact with the heated oxidizer solution or hydrocarbon fuel prior to formation of the emulsion mat:rix.
- 4b -B
According to the invention, an improved method for the production of water-in-oil explosive compositions which can be detonated with a No. 6 cap at diameters of 1.25" and lower and which do not contain an explosive ingredient or detonation catalyst is provided. These explosive emulsion compositions as well as microbubble containing noncap-sensi-tive water-in-oil emulsion blasting agents can be prepared as described below. The process and apparatus described herein is capable of producing such explosive compositions on a commercial basis in a manner providing for strict control of product quality and optimum safety during processing.
Basically, the process of the subject invention includes forming two premixes, one comprising an aqueous solution of inorganic oxidizing salts, and the' second compris-ing hydrocarbon fuel components, which provide the oil phase of the water-in-oil emulsion explosive composition, and mix-ing, on a continuous basis, these two premixes with an appro-priate amount of an emulsifier to form an emulsion matrix composition. The aqueous solution of oxidizing salts is heated to a temperature above the crystallization point of the solution and is maintained at that temperature, usually about 185 degrees F or greater, until the emulsion matrix is formed. The hydrocarbon fuel components are also heated to approximately the same temperature so as to avoid a rapid temperature drop upon admixture with the aqueous oxidizer solution. The emulsifier is added to the system in a manner such that the heat of the fuel and oxidizer solution does no_ cause it to degrade , j~r Z~l~
B7465 1l !! prior to formation oE the emulsion matrix. The emulsion matrix is ¦ formed by subjecting the hydrocarbon fuel component, the aqueous ! solution of inorganic oxidizing salts and the emulsifier to mixing l conditions sufficient to obtain emulsifying shear rates within the ¦`mixer. The term "emulsifying shear rates" as employed herein is ! defined to mean shear conditions at least equal to those obtained when the above-described components are mixed in a continuous ¦¦recycle mixer (further described below) at pressures of from about l~10 to about ~0 psig and preferable of from about 35 to about 40 Ipsig, residence times of about 4.5 seconds, and typical impeller ¦!speeds of at least about 1400 rpm (based on the use of a continuouc ¦Irecycle mixer having a 6" i~peller diameter). The emulsion matrix ¦Iprepared in this manner is fed on a continuous basis to a paddle ¦¦or ribbon type continuous blender where glass or resin jimicrobubbles, and, if desired, an auxiliary fuel such as particulate aluminum, are blended therewith to form the cap ~sensitive water-in-oil explosive compositions. Noncap-sensitive ¦jexplosive emulsions can also be produced by varying the Ilcomposition of the explosive emulsion such as, for example, Illowering the amount of microbubbles employed. It has been ¦laiscovered that in order to obtain products of uniform composition ¦ithe microbubbles must be fed to the continuous blender from a ¦ireservoir thereof containing a quantity of deaerated microbubbles.
iAs further described below, microballoons because of their ~25 j'peculiar shape, low density and flow characteristics are difficult ~to measure and add in a predetermined fashion if the microbubbles ~have been mixed with the normal amount of air which will come in ¦'contact therewith during handling and delivery to the blender.
ll 01~
~ i B7~65 , The above process can be conveniently carried out on a commercial scale by employing an oxidizing solution production 'line for forming, filtering and metering the oxidizer solution to the continuous recycle mixer (or equivalent mixers), and a hydrocarbon fuel production line for similarly handling the oil phase of the water-in-oil emulsion explosive. After admixture of ,the two premixes to form an emulsion matrix, an emulsion matrix ,processing line can be employed to obtain the cap sensitive ~explosive compositions ready for packaging.
o i! Another aspect of the present invention involves the use ~~of a detonation trap located between the continuous recycle mixer t~which forms the emulsion matrix composition and the blender ,wherein microbubbles and particulate aluminum are blended with the ',emulsion matrix to produce the cap sensitive emulsion composi-~tions. ~asically, the detonation trap comprises a piece of ~,flexible conduit located between the mixer and the blender such I!
',that any conflagration which may be initiated in the mixer will 'not be transmitted to the cap sensitive materials being produced ~`in the blender down stream thereof.
" Various other functions and advantages of the process ; ~~and apparatus of the present invention will be apparent from a ,study of the drawing which depicts a schematic representation of ' ,one embodiment of the process of the present invention as well as ~from a study of the detailed descrlption contained hereinbelow.
'1', - 1 '; 7 ~1 ~ r l~Z~ 1 4 1~ ' B7~165 l ~DETAILED DESCRIPTION OF THE INVENTION
Now referring to the drawing a pre~erred embodiment of the process of the subject invention will be described in relation thereto. The aqueous solution of inorganic oxidizing salts will ~contain at least 64% by weight inorganic oxidizing salts selected ~from the group consisting of ammonium nitrate, alkali and alkaline earth metal nitrates and perchlorates. Normally ammonium nitrate ¦ will comprise at least about 53% by weight of the solution. The l aqueous solution of inorganic oxidizing salts can be prepared in ¦ a production line manner as follows. A reservoir tank 2 of an aqueous ammonium nitrate solution comprising from about 80% to labout 97~ by weight of ammonium nitrate and preferably about 93%
¦by weight of ammonium nitrate is kept heated (above the saturation I 1temPerature) at temperatures of from about 180 degrees F to about 290 degrees F by appropriate heat supplying means such as steam ~coils 4. Normally it is desirable to maintain temperatures ¦high enough throughout the system so that crystallization of the concentrated inorganic oxidizing salts in the aqueous solution ¦is prevented. The ammonium nitrate solution is pumped by an ¦outlet conduit 5 through pumping means 6 to oxidizer makeup tank l0 via conduits 8 and 9. An aqueous solution of sodium I ¦ perchlorate can also be added to oxidizer makeup tank l0 via conduits 14 and 9 and pumping means 16. Since the sodium ¦ perchlorate solution concentrations required are not usually ¦ commercially ava;lable, a sodium perchlorate makeup tank 18 can be provided with suitable agitation means 20 which can comprise a stirrer and electric drive means, and a heat supply such as steam coils 22. The sodium perchlorate solution can be pumped via I
I
2(~
B7465 ,, outlet conduit 24 and pumping means 16 into the oxidizer makeup tank 10 as described above. Sodium perchlorate recycle conduit ' 26 can be employed to recycle excess portions of sodium perchlorate solution back to sodium perchlorate makeup tank ~ 5 ,18 and thereby provide additional agitation. In addition, solid ; sodium nitrate may be added to oxidizer makeup tank 10 either ! manually or via conduits 28 and 9 from sodium nitrate holding bin 1! 31 by any number of conventional solid feed conveying means, such !l as screw conveyors and the like. If water is necessary in order jlto adjust the concentration of the inorganic oxidizing salt solution, water conduit 30 can supply same in a controlled manner via water metering means 32.
I~ Load cells 12, upon which oxidizing makeup tank 10 ,rests, automatically sense, by weight, the amount of oxidizin~
! salt solution present in oxidizer makeup tank 10 and automatically provide for shutdown of the pumping means 6 and 16 connected thereto when the predetermined amount of oxidizer solutlon has been deposited in makeup tank 10. Load cells 12 can also be i'employed to control the flow of solid ammonium nitrate. Oxidizer ~makeup tank agitation means 34 insures that a homogeneous solution ¦of the various inorganic oxidizing salts is prepared in oxidizer ,makeup tank 10. Heating means such as steam coils 36 are employed in order to keep the inorganic oxidizing solution at approximately jl90 degrees F, or above the crystallization temperature of the !particular oxidizing salt solution. The temperatures in the ¦,ammonium nitrate solution holding tank 2, the sodium perchlorate makeup tank 18, and the oxidizer solution makeup tank 10 can be , _ g _ ~ ?14 B7465 !
controlled by providing a number of automatic temperature recording and control means (TRC) depicted schematically in the drawing.
I The inorganic oxidizing salt solution is pumped from lioxidizer ma~eup tank 10 via outlet conduit 38, pumping means 40 and conduit 42, where filter means 4~, which can comprise screen or fabric type filtering devices, removes any particulate ¦contaminates and inorganic oxidizing salts which have failed to jgo into solution. The filtered inorganic oxidizing solution is ¦then delivered by conduit 46 to oxidizer holding tank 48 which is preferably of a slightly larger capacity than oxidiæer makeup tank ¦10. Oxidizer holding tank 48 is also supplied with a~itation ¦means 50 and steam coils 52. If necessary, water can be added to ¦the oxidizer holding tank 48 via water meter 54 and water conduit ¦ 56. On the other hand, it may be necessary to lower the water content of the aqueous oxidizer solution in order to increase the concentration of inorganic oxidizing salts, and in this case heat ~can be supplied by steam coils 52 in order to cause evaporation ~of water from oxidizer holding tank 48.
¦ Oxidizer solution pumping means 58 is preferably a highly accurate metering type pump preferably of the positive ¦displacement diaphragm type. Such pumps are capable of metering ¦rates of flow therethrough at tolerances of about + 1%. Suitable ¦such pumps are sold by Milton Roy Inc., Philadelphia, Pa.
¦under the trade designation MILROYAL. -~Z~14 .
B7~65 Dual filtering means 60a and 60b provide for a second filtration of the inorganic oxidizing salt solution as it leaves the metering pump means 58. Use of dual filters provides for reduced load on each filter and increased operation time between filter cleansing operations. Further~ore pumping can continue through one filter while the other is being-cleaned, thus avoiding ,shutdown of the process. An accumulator 62 is provided, including ; ,'pressurized air source 64 and pressure measurement means ~6 for the purpose of damping the oscillating pressure pulses which issue -Ifrom positive displacement diaphragm type metering pump 58. The loxidizing solution travels through feed line 68, which can be 'jsurrounded by a hot water jacket 70 supplied with stea~ or water l~at a temperature sufficient to keep the inorganic oxidizing solution above its crystallization temperature (about 190 degrees ~15 ~F). Metering means 72 provides for accurate measurement of the ~flow of the inorganic oxidizing solution through conduit 68 and ~rPlief valve 74 provides for the release of over pressure or any 'excess amounts of inorganic oxidizins solution from the system via j'drain conduit 76. Rupture disc 78 provides for emergency release ,of excess flow rates of the inorganic oxidizing salt solution.
One-way valve 80 insures that none of the hydrocarbon fuel phase (to be described below) backs up into the oxidizer solution portion of the system and thereby contaminating it. The junction lof inorganic oxidizing solution feed line 68 with hydrocarbon fuel 'lcomponent conduit 82 provides for the delivery of the two ,components to continuous recycle mixer 168 (described below) or ; lits equivalent.
.1i ' lj .1' .
! - ll - ¦
~ r ZOl~
.1 i B7465 ~) The preparation of the hydrocarbon fuel phase of the water-in-oil explosive compositions produced by the process of the subject invention will now be described with relation to the - ¦
drasYing. The f~el component can also be produced in a production line manner so as to facilitate continuous production of the emulsion explosive compositions on a commercial scale. The carbonaceous fuel component which is useful in preparing such ~compositions includes most hydrocarbons, for example, paraffinic, olefinic, naphthenic, aromatic, saturated or unsaturated ,hydrocarbons. In general, the carbonaceous fuel is a water limmiscible, emulsifiable fuel which is either liquid or ¦!liquefiable at a temperature up to about 200 degrees F, and jpreferably between about 110 degrees F and 160 degrees F. It is - ,, .
'preferable that the carbonaceous fuel include a combination of a lwax and an oil. However, waxes are not always necessary.
Suitable oils which can be used in the process of the subject iinvention include petroleum oils, various vegetable oils and 'various grades of dinitrotoluene; a highly refined mineral oil sold by Atlantic Refining Company under the trade designation , ATREOL; a white mineral oil sold under the trade designation ~RAYDOL by Witco Chemical Company, Inc., and the like. Thus, oil 'holding tank 84 provides a supply of oil to the system via conduit i86 and oil pumping means 88. Oil is p~mped via conduit 90 to fuel ~ llmakeup tank 92. Normally, the oil component of the carbonaceous -`25 ,Ifuel can be pumped at ambient temperatures without the necessity ~for heating the equipment.
..
ZOi~
l~
B7465 1l As noted above, in a pr~ferred embodiment of the subject invention a mixture of oils and waxes is~employed. ,S~uitable waxes ~which can he employed hav~e melting points of at least 80 degrees F
llpreferably in the range of about ll0 to about 200 degrees F.
liExamp1es o,f s~uitable waxes incl~de waxes derived from petroleum, ¦is~uch as petrolatum wax, microcrystalline wax, and paraEfin wax, ~mineral waxes such as ozo~erite and montan wax, animal waxes such !¦as spermacetic wax, and insect waxes such as beeswax and Chinese ¦¦wax~. !Preferred waxes include those identified by the trade 1ldesignations INDRA 11~3, INDRA 5055-G, .INDRA 4350-E, ,INDRA 2126-E
¦and .INDRA 2119 sold by Industrial Raw Materials Corporation, and a similar wax sold by Mobil Oil Corporation under the trade ¦designation MOBIL 150 as well as WITCO X145-A sold by Witco !Chemical Company Inc., and ARISTO 143 sold by Union 76 Co. These waxes can be charged manually, or by automatic conveyor means, to ¦wax melt tank 94, which is supplied with heating means such as steam coils 96, and agitation means 98, to thereby melt the wax and allow it to be pumped via outlet conduit 100, and wax pumping 'means 102, through conduit 104 to fuel makeup tank 92. Fuel Imakeup tank 92 is also supplied with heating means such as steam ¦~coils 106 so as to maintain the temperature of the oil-wax mixture ¦above its cQngealing point. Agitatlng means 108 is provided so as Ito insure a good mix between oil and wax components. Load cells ~10 are used to automatically control the oil pumping means 88 and ¦wax pumping means 102, these pumping means being automatically Ishut down when a predetermined weight of fuel components have been ¦Idelivere~l to iuel makeup tank 92. Fuel outlet conduit 112 and z~
I' .
B7465 ¦~
'pumping rneans 114 deliver the fuel component via conduit 116 to fuel holding tank 118 which is also supplied with agitation means ¦
120 and heating means such as steam coils 122. The heating means ¦
,described above are employed to raise the temperature of the hydrocarbon fuel component to approximately the same temperature ~as the oxidizing solution described above. Thus when the fuel and .,oxidizer components are mixed together there will be no cooling off of the oxidizer solution which misht result in undesirable licrystallization of the inorganic oxidizing salts. Fuel holding ¦¦tank 118 insures that a ready supply of hydrocarbon fuel component ~,(the oil and wax mixture) of the explosive compositions prepared iby the process of the subject invention are ready on a continuoùs ~basis for use in the process. E~ydrocarbon fuel line 124 delivers I,the hydrocarbon fuel component to the inlet of a metering fuel I'pump means 126 which is preferably of the positive displacement ,diaphragm type described above. Accumulator 128, or an equivalent jpulse dampening device, pressure sensing means 13Q and an air pressure source provide means for damping the pulsating flow of l,hydrocarbon fuel component through fuel conduit 134 to melt filter ll136. Filtered hydrocarbon fuel component ~separated from any - jlcongealed solid fuel by the filter) is delivered via conduit 138 - which is provided with heating jacket 140. ~letering means 142 '~provides for the controlled flow of the hydrocarbon fuel component ¦Ithrough line 82 where it contacts the aqueous inorganic oxidizing l,salt solution at the intersection of conduits 68 and 82. Between tmetering means 1~2 and the intersection of conduits 68 and 82, ¦,relief valve means 144 is provided for bleeding off any excess i - 14 -., .
f ~Z0~4 B7~65 1!
fuel component pressure delivered through meter 1~2, and rupture ¦.disc means 146 is provided for emergency relief of unexpected excesses flowing through line 82. One-way valve means 148 l'protects the fuel component line from contamination should a ',backup occur causing the inorganic oxidizing salt solution to flow back up conduit 82.
A suitable emulsifier used to form the emulsion matrix ,,from the aqueous inorganic oxidizing solution and the hydrocarbon ; I,fuel components described hereinabove is supplied via emulsifier l¦reserve tank 150 through conduit 152, pumping means 154, and conduit 156 to emulsifier holding tank 158. Emulsifiers useful in lithe preparation of water and oil explosive emulsions include those ¦iderivable from sorbitol by esterification with removal of one i,molecule of water such as sorbitan, fatty acid esters r for :lS ¦iexample, sorbitan monolaurate, sorbitan monooleate, sorbitan ~lmonopalmitate, sorbitan monostearate, and sorbitan tristearate.
; ¦,Other useful materials comprise mono- and diglycerides of ¦Ifat-forming fatty acids, as well as polyoxyethylene sorbitol ¦lesters, such as polyethylene sorbitol beeswax deriva~ive materials ~20 !and polyoxyethylene(4) lauryl ether, polyoxyethylene~2) ether, ¦.polyxyethylene (2) stearyl ether, polyoxyalkylene oleate, ,polyoxyalkylene oleyl acid phosphate, substituted oxazolines and phosphate esters and mixtures thereof and the like. Emulsifiers ,of this general type are delivered via outlet conduit 160 and 'metering pump means 162, which is preferably of the positive displacement diaphragm type described above, to emulsifier conduit ~64 which enters :euel component conduit 82 near the intersection - 15 - ~
., B7465 1l of conduits 82 and 68. It has been discovered that many of the ~emulsifiers use~ul in the emulsion explosive compositions of the ~present invention will tend to degrade with time if exposed to the relatively high processing temperatures of the present invention.
Therefore, it has been found to be especially preferable to introduce the emulsifier, at substantially ambient temperatures, ~at a point just prior to mixing oE the fuel component and ,~inorganic oxidizing salt solution to form an emulsion matrix. Of i~course, the emulsifier could be added directly to the mixer or ~could be added in conjunction with the inorganic oxidizing salt solution, however, it has been found to be preferred to allow the 'emulsifier to admix with the fuel component just prior to the ,admixing of these materials with the inorganic oxidizing salt 'solution.
~ The process step of admixing the fuel component with the 'inorganic oxidizing salt solution will now be described in detail ¦!with reference to the drawin~. As noted above, the emulsifier i.
preferably enters the fuel component conduit 82 at a point just prior to where conduit 82 joins oxidizing solution conduit 68.
~20 ~The mixture of the inorganic oxidizlng solution and fuel component ,can then be further processed in a single emulsion matrix processing line which basically comprises a continuous recycle ~ixer, for forming the emulsion matrix, and a blending apparatus I!for the addition of sensitizing agents, such as microbubbles, the ,mixer and blender being separated by a detonation trap for safety ¦,reasons described below. Thus, the oxidizer solution and fuel mixture is delivered via conduit 166 to a mixing means such as 1~ 4 , .
ill B7~65 ~continuous recycle mixer 168. Temperature sensing means 167 and 169, com~unicating with the inlet and outlet, respectively of continuous recycle mixer 168 provide for monitoring of process conditions within the mixer and can be used as warning devices should the mixer develop mechanica:L problems. Suitable continuous recycle mixers are available from Chemetron, Inc., sold under the trade na~e VOTATOR CR MIXER. Basically, a continuous recycle mixer provides for a constant residence time of materials therein I'but provides for continuous recycling of the materials over a ilseries of intermeshing pins so that the hydrocarbon fuel and ~'oxidizer solution are thoroughly mixed in the presence of the ,lemulsifier. Continuous recycle mixers accomplish this action by j¦means of a multi-vaned impeller sandwiched between two discs.
'Each of the discs have a series of pins thereon which mesh with jpins on the mixer housing. ~y providing apertures on the discs which cause material in the mixer to be recycled back through the intermeshing pins prior to passage out of the mixer, the recycle mixing action is accomplished. Such action within the mixer ,'provides for extremely good admixture of the fuel component with ,the inorganic oxidizing component and insures production of a stable emulsion. It has been discovered that operating such a ,Imixer, having an impeller of about 6" in diameter, at rotor speeds iof from about 1400 rpm and at pressures within the mixer of from ,about 35 to about 40 psig, with average residence times of about l~4.5 seconds, results in an extremely stable emulsion matrix useful in the production of cap sensitive water-in-oil explosive emulsion compositions. Of course various other operating parameters can , 1 l . ~
s7465 il I be employed, depending upon the particular size of the mixer and the amount of product being processed, but the emulsifying shear rate conditions must be maintained in order to obtain stable emulsions. ~hile continuous recycle mixers have been found to be excellent means for obtaining the recessory emulsifying shear rates other mixers which can be employed include in-line mixers such as those sold under the trade designation TUREON/ by Tobert ¦ Industries, Inc., Southbridge Mass. or colloid type mixers such l! as an OAKES mixer sold by E.T. Oakes Corp., Islip, N.Y.
ll The emulsion explosive matrïx formed in mixer 168 is ¦¦delivered via outlet conduit 170, through detonation trap 172 ¦~(described below), to pinch valve means 174. Pressure sensing ¦`means 176 is preferably automatically interconnected with pinch ~Ivalve means 174 to regulate the pressure in ~ixer 168 so that it lfalls within the ranges described above in order to produce the stable emulsion matrix within mixer 168. Furthermore, pressure ¦Isensing means 176 also provides for the monitoring of the emulsion matrix leaving mixer 168 via conduit 170 to insure that the i,mixture is emulsified to the desired extent. If the emulsion jshould "break", that is, if the aqueous oxidizer solution failed ¦¦to become emulsified into discrete globules contained within a ,continuous oil phase, the pumping characteristics of the matrix ¦flowing through outlet conduit 170 will change drastically causing Ija reduction in pressure sensed by pressure sensing means 176.
-25 i~,Thus, either throu~h manual inspection or by automatic means, pressure sensing means 176 will indicate that undesirable "broken"
m~ixtures of the aqueous oxidizer solution and the fuel components 1 . I
i - 18 -f~
I' ll B7465 !~
¦'are exiting from mixer 168. Appropriate remedial action can then i be taken manually, or automatically, to avoid conta~ination of ! down-line product, for example by controllin~ pinch valve 174.
,~ Detonation trap 17~ basically comprises a flexible S , conduit which has been discovered to prevent a conflagration initiating in the mixer 168 or conduit 170 from propagating there-through and reaching the continuous blender described below.
~Basically, the detonation trap 172 can be manufactured from any of a number of chemically inert elastomeric substances which are ¦~capable of withstanding the pressures and temperatures employed in the process, as well as the chemical action of the emulsion matrix !j passing therethrough. For example, in a process wherein the flow l~rate through conduit 170 is about 50 lbs./minute a flexible piece ; ¦!of tubing approximately 18" in length having an internal diameter ~15 l¦of 1-1/2" and manufactured from rubber, polyethylene or a ¦Icomposite of these and similar materials can be used as the j~detonation trap of the present invention. A typical hose used ~or ¦this purpose is sold under the trade designation FLEXWING by I,Goodyear Tire and Rubber Co. of Akron, Ohio which comprises a ! polyethylene tube and reinforced rubber cover with spiral wire ,helix between braided synthetic yarn.
¦I The emulsion matrix passes via pinch valve 174 into iconduit 178 and into continuous blender 180. Continuous blender ¦ilg0 provides for the admixture of the emulsion matrix with closed icell void containing materials such as glass or resin ¦microbubbles. Glass microbubbles are pre~erred. Particulate metal fuels, and the like, such as particalate aluminum, for ' .
Ii .
B~465 example, can also be added and thoroughly admixed with the ¦! emulsion matrix in continuous blender 180. Continuous blender 180 ¦'preferably comprises any of a number of continuous blenders of the ¦,paddle type such as those sold by Sprout Waldon Co., Day Mixing ilCQ. and Cleveland Mixer, Co., although other types of blenders, ~including ribbon type:blenders,,for example, can be employed.
The microbubbles are added to the system via vacuum line .182 which sucks microbubbles,from a storage barrel or other ~,container 184. This method of feed provides for minimizing the !dispersion o,f microbubbles in the air so as to avoid health hazards. Vacuum line 182 delivers the microbubbles to microballoon hopper 184. It has been discovered that because of the fine particulate nature of the microbubbles the flow Icharacteristics ~f a guantity thereof is highly dependent upon how `15 ¦I,long they have been allowed to settle after transportation via a Ivacuum source whereby air is intermixed therewith. Thus, ¦microbubbles which have been transported and admixed with air have ¦flow characteristics very similar to those of water and will pour, ~,at rates which are hard to control, into the feeder mechanisms for ¦,the:blender,180. This condition is very undesirable as close j~control of the amount of microbubbles being admixed with the emulsion matrix is critical if ~uality products are to be ~attained. Therefore, it has been discovered that microbubble hopper 184 should provide for a residence time of at least 4 ~25 'minutes to thereby allow the microbubbles to deaerate and become packed within the hopper~l84~ ,However, once the microbubbles ~deaerat a~d sett:Le withi~ the hopper, their flrw characteristic~
1~
~ ~ - 20 - ~
f Z~14 I!
B7465 l become similar to those of normal solid materials and flow out of ¦the hopper will not proceed at an even rate under gravitational ~force alone. Therefore, a screw feed mechanism 186, such as a l~.Soder prefeed screw mechanism sold ~y The KTron Corporation, can ¦:he employed to feed the microbubbles from hopper 184 to a ,weigh-helt type of,feed mechanism :l88. The screw feeder must be of the dual screw type having mesh:ing flights such -that the flow of the microbubbles therealong can be controlled. The weigh-belt l can be those sold under the trade name KTRON by RTron Corporation, ¦ Glasboro, N.J. ;The weigh-belt mechanism,188, in conjunction with the screw feed mechanism 186, can be employed to deliver a closely controlLed quantity of microbubbles to the continuous blender 180.
~The amount of microbubbles can be controlled either on the basis lo~f volume or on the basis of weight, as desired. This,feature is I.especially desirable since the density of a selected grade of ¦microb,ubbles may vary:widely. .For example microbubbles listed as having a density of "0.15/cc" may vary between about 0.12 and ¦Q~18 g/cc. Therefore, i,f the,final end product is desired to have a specified total weight percent of microoubbles, the weigh-belt ~20 ¦ Jfeed mechanism 188 can be employed to deliver a known quantity of miarobubbles to tne continuous blender 180 based on the flow rate ¦ of the emulsion matrix into mixer,l80 via conduit 178. On the other hand, if a controlled density product is desired, the screw ,~feed mechanism,l86 can be employed to provide for specific volumetric additions of microballoons to weigh feed belt feeder mechanism-188 (which in that case merely acts as a conveyor belt), and then to blender 180, to provide for the production of a product having kno.wn density characteristics.
1, B7465 1;
The finished water-in-oil explosive compositions exit blender 180 via er.it conduit 190, and screen 192 and are delivered to packaging apparatus where the emulsions can be packaged as desired, for example, in cardboard or paper cartridges, plastic bags and the like.
While this invention has been described in relation to .its preferred embodiments it is to be understood that various modifications thereof will now be apparent to one skilled in the 'art upon reading this specification and it is intended to cover i,all such modifications as fall within the scope of the appended ,Iclaims.
11i ~
~' .
Claims (23)
1. A process for producing explosive emulsion compositions sensitized with microbubbles comprising:
a) forming an aqueous inorganic oxidizing salt solution of at least about 64% by weight inorganic oxidizing salts and maintaining said solution above the crystallization temperature thereof;
b) forming a hydrocarbon fuel component and heating it to approximately the same temperature as said oxidizing solution;
c) introducing said oxidizer solution, said hydrocarbon fuel component, and an emulsifier to a mixing zone and mixing at conditions sufficient to obtain emulsifying shear rates to thereby form an emulsion matrix, said emulsifier being added in a manner such that the time of contact with the heated oxidizer solution and hydrocarbon fuel component is not sufficient to cause said emulsifier to degrade prior to the formation of said emulsion matrix; and d) blending with said emulsion matrix a predetermined quantity of microbubbles delivered from a deaerated supply thereof to form explosive emulsion.
a) forming an aqueous inorganic oxidizing salt solution of at least about 64% by weight inorganic oxidizing salts and maintaining said solution above the crystallization temperature thereof;
b) forming a hydrocarbon fuel component and heating it to approximately the same temperature as said oxidizing solution;
c) introducing said oxidizer solution, said hydrocarbon fuel component, and an emulsifier to a mixing zone and mixing at conditions sufficient to obtain emulsifying shear rates to thereby form an emulsion matrix, said emulsifier being added in a manner such that the time of contact with the heated oxidizer solution and hydrocarbon fuel component is not sufficient to cause said emulsifier to degrade prior to the formation of said emulsion matrix; and d) blending with said emulsion matrix a predetermined quantity of microbubbles delivered from a deaerated supply thereof to form explosive emulsion.
2. The process of Claim 1 wherein said oxidizing salt solution is maintained at a temperature of about 187 degrees F.
3. The process of Claim 1 and further comprising blending with said emulsion matrix a particulate metal.
4. The process of Claim 3 wherein said particulate metal is particulate aluminum.
5. The process of Claim 1 and further comprising filtering said aqueous inorganic salt solution and said hydrocarbon fuel component prior to introduction into said mixing means.
6. The process of Claim 1 wherein said emulsifier is added to said hydrocarbon fuel component and dispersed therein at a point prior to introduction of said hydrocarbon fuel component to said mixing means.
7. The process of Claim 1 wherein said microbubbles are delivered from said deaerated supply thereof for blending with said emulsion matrix on the basis of a predetermined weight percent of microbubbles, based on the weight of the explosive emulsion.
8. The process of Claim 1 wherein said microbubbles are delivered from said deaerated supply thereof for blending with said emulsion matrix on the basis of a predetermined volume thereof to obtain explosive emulsions of a predetermined density.
9. The process of Claim 1 wherein said mixing means is continuous recycle mixer.
10. A process for producing cap sensitive water-in-oil explosive emulsion compositions sensitized with microbubbles comprising:
a) filling an oxidizer solution holding tank with an aqueous solution of inorganic oxidizing salts comprising at least about 67% by weight of said inorganic oxidizing salts and maintaining said solution at a temperature above about 187 degrees F;
b) filling a fuel component holding tank with a quantity of hydrocarbon fuel component and heating said hydrocarbon fuel component to substantially the same temperature as said oxidizer solution;
c) simultaneously passing controlled proportions of said oxidizing component and said fuel component to a mixing zone, adding an emulsifier to said fuel component at a point just prior to said mixing zone such that said emulsifier is not degraded from contact with said heated hydrocarbon fuel;
d) mixing said oxidizer solution, hydrocarbon fuel, and emulsifier components in said mixing zone at conditions sufficient to obtain emulsifying shear rates to form an emulsion matrix; and e) blending with said emulsion matrix a predetermined quantity of microbubbles to thereby form said cap sensitive water-in-oil composition.
a) filling an oxidizer solution holding tank with an aqueous solution of inorganic oxidizing salts comprising at least about 67% by weight of said inorganic oxidizing salts and maintaining said solution at a temperature above about 187 degrees F;
b) filling a fuel component holding tank with a quantity of hydrocarbon fuel component and heating said hydrocarbon fuel component to substantially the same temperature as said oxidizer solution;
c) simultaneously passing controlled proportions of said oxidizing component and said fuel component to a mixing zone, adding an emulsifier to said fuel component at a point just prior to said mixing zone such that said emulsifier is not degraded from contact with said heated hydrocarbon fuel;
d) mixing said oxidizer solution, hydrocarbon fuel, and emulsifier components in said mixing zone at conditions sufficient to obtain emulsifying shear rates to form an emulsion matrix; and e) blending with said emulsion matrix a predetermined quantity of microbubbles to thereby form said cap sensitive water-in-oil composition.
11. The process of Claim 10 and further comprising blending with said emulsion matrix a predetermined amount of a particulate metallic fuel component.
12. The process of Claim 11 wherein said particulate metallic fuel component is particulate aluminum.
13. A system for producing water-in-oil explosive compositions on a continuous basis comprising:
(a) an aqueous oxidizer solution production line comprising:
i) inlet conduit and pumping means for delivery of inorganic oxidizing salts and water to an oxidizer solution makeup tank,said tank having load cell means interconnected with said input pumping means for automatically stopping the delivery of aqueous oxidizer salt solutions thereto once a predetermined quantity has been deposited therein, ii) heating means for maintaining the oxidizing solution delivered to said oxidizer solution makeup tank at a temperature above the crystallization point of said solution, iii) filter means for filtering the aqueous oxidizer solution delivered from said tank, and iv) outlet conduit and metering pump means for delivering said oxidizing solution from said tank at preselected flow rates;
(b) a hydrocarbon fuel component production line comprising:
i) inlet conduit and pumping means for delivery of hydrocarbon fuel components to a hydrocarbon fuel makeup tank said tank having load cell means interconnected with said input pumping means for automatically stopping delivery of hydrocarbon fuel thereto once a predetermined quantity has been deposited therein, [Claim 13 continued]
ii) heating means for heating said hydrocarbon fuel to approximately the same temperature at which said oxidizer solution is maintained, iii) filter means for filtering said hydrocarbon fuel delivered from said hydrocarbon fuel tank, and iv) outlet conduit and metering pump means for delivering hydrocarbon fuel from said hydrocarbon fuel tank at preselected flow rates;
(c) an emulsion matrix processing line for forming an emulsion matrix from the hydrocarbon fuel delivered by said hydrocarbon fuel production line and said oxidizer solution delivered by said oxidizer solution production line and processing said emulsion matrix into emulsion explosive compositions comprising:
i) mixing means having an inlet connected to the outlet conduits of said aqueous oxidizer solution production line and said hydrocarbon fuel production line and an outlet;
ii) blender means connected to the outlet of said mixing means for blending sensitizing agents with said emulsion matrix to form said water-in-oil emulsion explosive compositions;
iii) flexible conduit detonation trap means interconnected between said mixer and said blender for containing any conflagration initiated in said mixer and thereby preventing said conflagration from detonating
13. A system for producing water-in-oil explosive compositions on a continuous basis comprising:
(a) an aqueous oxidizer solution production line comprising:
i) inlet conduit and pumping means for delivery of inorganic oxidizing salts and water to an oxidizer solution makeup tank,said tank having load cell means interconnected with said input pumping means for automatically stopping the delivery of aqueous oxidizer salt solutions thereto once a predetermined quantity has been deposited therein, ii) heating means for maintaining the oxidizing solution delivered to said oxidizer solution makeup tank at a temperature above the crystallization point of said solution, iii) filter means for filtering the aqueous oxidizer solution delivered from said tank, and iv) outlet conduit and metering pump means for delivering said oxidizing solution from said tank at preselected flow rates;
(b) a hydrocarbon fuel component production line comprising:
i) inlet conduit and pumping means for delivery of hydrocarbon fuel components to a hydrocarbon fuel makeup tank said tank having load cell means interconnected with said input pumping means for automatically stopping delivery of hydrocarbon fuel thereto once a predetermined quantity has been deposited therein, [Claim 13 continued]
ii) heating means for heating said hydrocarbon fuel to approximately the same temperature at which said oxidizer solution is maintained, iii) filter means for filtering said hydrocarbon fuel delivered from said hydrocarbon fuel tank, and iv) outlet conduit and metering pump means for delivering hydrocarbon fuel from said hydrocarbon fuel tank at preselected flow rates;
(c) an emulsion matrix processing line for forming an emulsion matrix from the hydrocarbon fuel delivered by said hydrocarbon fuel production line and said oxidizer solution delivered by said oxidizer solution production line and processing said emulsion matrix into emulsion explosive compositions comprising:
i) mixing means having an inlet connected to the outlet conduits of said aqueous oxidizer solution production line and said hydrocarbon fuel production line and an outlet;
ii) blender means connected to the outlet of said mixing means for blending sensitizing agents with said emulsion matrix to form said water-in-oil emulsion explosive compositions;
iii) flexible conduit detonation trap means interconnected between said mixer and said blender for containing any conflagration initiated in said mixer and thereby preventing said conflagration from detonating
[Claim 13 continued]
the water-in-oil explosive emulsion composition formed in said blender; and (d) an emulsifier holding tank connected to a delivery conduit and metering pump means for delivering said emulsifier to said mixing means said delivery conduit entering the system at a point such that said emulsifier will not degrade from contact with the heated oxidizer solution or hydrocarbon fuel prior to formation of the emulsion matrix.
the water-in-oil explosive emulsion composition formed in said blender; and (d) an emulsifier holding tank connected to a delivery conduit and metering pump means for delivering said emulsifier to said mixing means said delivery conduit entering the system at a point such that said emulsifier will not degrade from contact with the heated oxidizer solution or hydrocarbon fuel prior to formation of the emulsion matrix.
14. The system of Claim 13 wherein said mixing means is a continuous recycle mixer.
15. The system of Claim 13 and further comprising a pressure sensing means communicating with the outlet of said mixing means mixer for indicating the pumping properties of the emulsion matrix leaving said mixer.
16. The system of Claim 15 and further comprising cutoff valve means interconnected to said pressure sensing means for automatically stopping flow between said mixing means and said blender when said pressure sensing means indicates that the emulsion matrix has broken.
17. The system of Claim 13 and further comprising an oxidizer solution holding tank interconnected between said oxidizer solution makeup tank and said oxidizer solution metering pump means.
18. The system of Claim 17 wherein said oxidizer solution holding tank and makeup tank are equipped with agitation means.
19. The system of Claim 13 and further comprising a hydrocarbon fuel holding tank interconnected between said hydrocarbon fuel makeup tank and said hydrocarbon fuel metering pump means.
20. The system of Claim 19, wherein said hydrocarbon fuel makeup and holding tanks are equipped with agitation means.
21. The system of Claim 13 and further comprising sensitizer feed means for delivering sensitizing agents to said blender, said feed means comprising a hopper means wherein sensitizing agents can be deposited and allowed to deaerate prior to blending.
22. The system of Claim 21 wherein said sensitizer feed means comprises a dual screw particulate material feeder apparatus.
23. The system of Claim 22 and further comprising a weigh-belt feeder apparatus which receives the sensitizing agents fed by said dual screw feeder and deposits said sensitizing agents into said blender.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000315956A CA1122014A (en) | 1978-11-08 | 1978-11-08 | Production of explosive emulsions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000315956A CA1122014A (en) | 1978-11-08 | 1978-11-08 | Production of explosive emulsions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1122014A true CA1122014A (en) | 1982-04-20 |
Family
ID=4112918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000315956A Expired CA1122014A (en) | 1978-11-08 | 1978-11-08 | Production of explosive emulsions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1122014A (en) |
-
1978
- 1978-11-08 CA CA000315956A patent/CA1122014A/en not_active Expired
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