US1765771A - Preheating system - Google Patents

Description

8 2 1930- F. PUENING 1,765,771 I PREI-IEATING SYSTEM 7 Filed July 20. 1927 -3 Sheets-Sheet l E IN V EN TOR.

190/72 Puen/n June 24; 1930. U 1,765,771 PREHEATING SYSTEM Filed July 20, 1927 SYShee ts-Sheet 2 ATTON June 24, 1930. F. PUENING 1,765,771-

' PREHEATING SYSTEM,

Filed July 20, 192.7 3 Sheets-Sheet 3 I INVENTbR. Franz/ km -BY v @TRNY.

Patented June 24, 1930 ,FRANZ PUENING, or OHARA 'rownsmr,

AssIeNon-To THE xorrnas comm ALLEGHENY comm-Y, IPENN'SYLVANIA,

1w, acoarom'rion or DELAWARE Application filed J'uly 20, 1927. Serial No. 207,043.

My invention relates to preheating systems, and particularly to preheating systems for preparing coal for carbonization in coke ovens or other carbonizing apparatus.-

My invention has, for one of its objects, to provide a preheating system of large capacity that operates continuously to preheat and prepare coal to be supplied to coke ovens and the Another object of my invention is to pro-' vide a preheater that is relatively small and inexpensive by reason of its comprising compact groups of heating fines through which the entire stream of coal moves uniformly at such speed that local overheating is avoided.

A further object of my invention is to provide a preheater in which previously preheated coal is mixed with the wet unheated I coal whereby a portion of the moisture of the latter is initially evaporated and the temperature ofthe mixture is maintained above that at which water vapor condenses so that the vapors from the preheater do not condense upon the incoming coal and clogging of the stream of coal is thereby avoided.

A further object of my invention is to provide preheating apparatus wherein the material to be treated follows such course through the preheater that substantially the entire mass comes in contact with the heated por' tions thereof.

A further object of my invention is to provide apparatus for prehatingcoal in which gases of relatively high temperature maybe employed without damage to fines of metal or other material adapted for lower temperatures.

A still further object of my invention is to'provide a simple and eflicient means whereby Waste gases may be employed to protect surfaces of non-refractory materials from gases of combustion.

It has been demonstrated that coal or other carbonaceous material that is supplied to coke ovens or other carbonizing apparatus may be more easily carbonized if the coal has been heated to desired or predeterminedtemperature's before being supplied to the coke ovens. It has been found, for example, that the time required for'c oking may be materially reduced and that in some cases the efiiciency of the system is materially increased when dry and eated coal is supplied to the carbonizmg apparatus. It has also been found that an lmprovement incoke structure may re.- sult from preheating the coal.,

Preheating systems have been proposed heretofore but they have not, in general, been of a type suitable for treatinglarge quantities of coal.

It has'heretofore been diificult to build preheaters of reasonably small or compact size. If, for example, coal were passed through a a vertical tube or shaft that is heated on the outside, the coal would become heated somewhere in the middle portion of the shaft and give oif water vapor. The vapor would force its Way both upwardly and downwardly, with the result that the portion of the vapor going upwardly would condense in the colder portions of the incoming coal. The origina raw coal containingsome moisture would then become so wet, that it would clog the shaft and cease to'flow downwardly; Inv order to overcome this condition, it has been necessary to use shafts of a very considerable diameter through which a heavy column of very wet coal is able to pass down due to its weight, and in spite of its wetness. However, shafts of such largediameter occupy much space and the preheaters are very bulky and expensive.

This same condition of course also prevails if coal is passed through a tower containing many hotrizontal heating fiues. The coal somewhere in the center of the tower would give ofi' its moisture in the'formof vapor and this would partially condense in the upper part of the tower in the cold coal. In such a tower with horizontal heating flues, the wet coal would, of course, still more easily clog the preheater than in straight vertical shafts, because of the many changes of direction which the coal has to execute while descendmg. I

It has also been difiicult, if not impossible, to operate preheating apparatus efiiciently by reason of the limitations as to fuel and temperatures that may be employed. For examso i ther' passage In theaccompanying drawings, 1

pipes, or similar apparatus that have been heated approximately to the temperature of 5 gases of combustion, may be heated beyond the desired or predetermined temperature, with the result that the coal first becomes fused and adherent to the wall so that furof such coal would temporarily be blocked and that later actual coke formation would occur with the result that flow through the 'preheater may becompletely stopped. At thesame time the'metal flues would become so overheated that they would soon burn out. Such partial carbonization may also result in loss of valuable gases, or

" other; by-products.

; Ixf fggccordance with the present invention, e p reheating apparatus to which coal maybe supplied continuously at its receiving end afidfiiigperly heated, or treated, coal may i, be withdrawn at the output end at a substantially uniformrate.

The wet orunheated coal is intimatelyixed with a relatively large I 1 uantity of heated coal, by means of which t e untreated-yitoal is initially heated before it enters the preheating apparatus. 1

The proportiop, of mixture between hot coal anc' 'c old or cal issue ratufre to which t e'wvet co preheated 1s so high that a portion of itsmoisture is evaporated and that the temperature of the mixture ofahot coal and original cold coal is above the condensing point of water vapor when it comes intocontact with the heating flues or enters into the spaces between these 'fluesor into other narrowspaces. This mix- ;ture upon its descent through the preheater is met by water vapor coming from portions of, hecoal below, but since this mixture has a temperature above the condensing point for water vapor, the rising vapor cannot possibly condense upon the incoming mixture and thus the latter retains its mobility or fluidity, and descends-through the narrow passages of the preheater without stoppage. The preheating apparatus of my invention is also provided with means whereby the waste gases maybe utilized to form a protecting layer. or envelope for the entrance portions of the flues through which gases of com-. bustion are circulated. Efficient means arealso provided for insuring that-substantially 5 all the coal being treated comes in contact with one or more of the flues. I

:Fi re 1 is a view, in vertical section ,the hne I-I of Fig. 2, of preheating appara- 1 his constructed in accordance with my inven- 1 tion" 2 is a similar view of the reheatin apparatus, taken along the line I -II o 'Fi.1' 1 igf3 is an enlarged fragmentary vertical e tion of s material 19, is spaced sectional view on line III-III of Fig. 1 showing the arrangement of the flues;

ig. 4 is an enlarged fragmentary view on line IV-IV of Fig. 5 of the entrance end of one of the flues; and

Fig. 5 is an enlarged fragmentary View, in

longitudinal section on line VV of Fig. 4, p

of one of the flues.

Referring particularly to Figs. 1 and 2, a preheating apparatus constructed in accordance with my invention com call -extending heating cham er 1, that is rises a vertipre erably of rectangular cross-section and that is traversed by a comparatively large number of horizontally-extending flues 2. A combustion chamber 3, which may be supplied with fuel, such, for example, as coke,

' coal or other material, supplies gases of combustion for heating the flues 2.

skip hoist mechanism 4 comprising skips or buckets 5 supplies coal to be heated in the heating chamber. A series of connected conveyors-6, 7 and 8 receive the treated material from the heating chamber and,

supply new material for mixture therewith in a manner to be hereinafter described.

A blower, or centrifugal pump 9 withdraws the spent or waste gases after they have traversed the flues 2 and supplies a' porses to the entrance portions of the flues ad] acent to the combustion chamber 3. An agitating mechanism for insurinlg1 the continuous passage of the coal throug the heating chamber 1 com rises a plurality of vertica y-extending re s 11 that are reciprocated by means of horizontally-extend- 'ing members 12 that are provided with crank arms13 which are connected to cranks 14,

operated by gear mechanisms l5.

- Referring particularl transversely-extending use 2 are arranged in horizontal rows, the members of rows being staggered with respect to adjacent rows. The upper side portions of all of the flues,-except those of the upper row, are arranged with inclined portions of unequal lengths, coal are shifted into diflcrent relative positions with respect to the flues as the coal passes successive rows of flues. v

Reference ma now be had to Figs. 4 and one of the flues of the lower rows for receiving the hot gases initially are clearlgshown. The

' entrance end,16 of the flue, whic is hexagonal in'cross-section and projects through the'wall to Figs. 2 and 3, the

the several whereby portions of the streams of 5, in which the etails of the entrance end of "of the chamber, is partially covered by a metal along plate 17 having arectangular open1ng'18 of smafller cross-section'than that. of the flue. The plate 17, which is covered by refractory y from the .flue and is connected thereto by four metal lugs or projections 20that are preferably wel one of the flues is typical of the entrance end 0 7 ed in sition. The arrangement just described or of each of the flues adjacent to the combus tion chamber 3, only a portion of the plate 17 and its refractory covering bein shown in Figs. 4 and 5. A separate plate 1 is prefer ably provided for each of the flues. Be erring again to Fig. 1, it willbe noted that. the entrance ends of the several flues which communicate directly with the combustion chamber 3 are artiall covered by the plate member 17 and the re ractory material 19, referred to in connection with Figs. 4 and 5. A rectangular space between the late 17 and the outside wall of'the heating cii ber 1 communicates with all of the flues that are covered by the plate 17 by means of a relatively narrow aperture 21.

a The operation of the heating system will 1 now be described. Gases from the combustion chamber 3 pass through the several rectangugo 'lar openings 18 in the late 17 and the refrac 'tory material 19 into t e group of flues 2 that are connected to the combustion chamber. The combustion gases may have a temperature, for example, of 3,000 F. At the u 5 end of the heating chamber, the relatively cool flue gases are withdrawn through a pipe 23 that is connected to the blower 9 and are conveyed through pipes 24, 25 and 26'to the 1 speed lower corners of the rectangular space be- 30 tween the plate 17 and the wall of the chamber J 1. These gases are supplied also to theupper lviewed in Fig. 1.' A portion of the eated corners of the rectangular space by pipes 27 which connect to the the waste gases is allowed to escape through s5 a .vertically extending pipe 28.

gases from the blower'9 which are supplied to the aperture 21 may have a temperature of .approximately500" I 4 thereof andform an envelope for the hotter I ases whereby damage -'to the-walls of. the fines "18' prevented.- The-resultant mixture of the gases has aninitial temperature of a proximate] 1500 R, which maybe safe y withstood y the flue walls.

l -,31 are provided, whereby caused to take a tortuous .i'several groups of flues in ases emerge from the u per grou of flues cm which they are with rawn byt e blower 9', they have a temperature of approximately ".5000 "I 1:.

4, which empty into a suit ate continuously'to agitate the streams of 'motion.-.. l v. p

The speedat which the coal passes through per pipe 24. A portlon of the conveyor 8, by means of which it is trans- The waste The high-temperature gases from the com bastion chamber 3 flow through the relatively small openings18 into the central I or-.

waste gases supplied throughithe a itul'es intimately mixed with J ing its passage through the remainder ofthe .110

. to the position indicated'by dotted lines when It. will be noted that suitable bafiles 30 and the hot gases are. path through the series. When the It may be assumed that a textured heated and untreated vor unheated coal, orother materiah is being supplied to' the top of the heating chamber by the bucket-s 5 of the skip hoist mechanism able-hopper-,2. I flows downwardly by force of gravity be- J tween the supp ying of the unheated coal to The materialto be heated;

through the heating chamber 1. It will be tween the several flues 2. A portion of the coal is adjacent to the initial rows of flues and itis heated thereby. As the columns. move downwardly, they are'divided into unequal portions by the inclined sides of the succeeding row of flues, whereby coal that has; not been heated directly by the flues is broughtinto engagementvwith the sides of the flues in the next row." In asimilar -manflues are divided in suc manner that sub stantially all of the coal is in contact with *1 one or more of the flues during its downward passage. In order to prevent the coal remaining-stationary and becoming carbonized or excessively heated, the agitating mechanism comprising the reciprocatingrods 11 may operner, the columns of coal lpassing each row of a y coal in order-thatthelatter maybe kept in the heating chamber is regulated by the sev-;

.eral discharging rotors 33,- which f serve to support the coal in the heating chamber and :1.

. discharge it into the hopper 34." The amount g cham of coal passing throu the heatin beer in a given vtime-being regulator? by the at which the'discharge rotorscare rotated; Thehopper 34 guides the coal into the conveyor 7 WhlCh conveys it to the ri ht, as

coal, for example, one-fifth, is diverted into ported to a suitable storage chamber (not shown).

The conveyor 6, which is connected to a source of coal that is unheated and which contains moisture, supplies unheated coal to the conveyor 7 in an amount equal-to that withdrawn by the conveyor 8. The unheated coal, which may constitute approximatly one-fifth of the coal in the conveyor 7, is'

the heated coal dur ,thatreturns to its operative position when the bucket is again lowered. The buckets 5 carry the mixture of heated and unheated coal received from the hoppers 36 to the top of the preheater, where they empty into the hopper 32, connected to the top of the heating -During the eriod of time elapsing bethe conveyor 7 and the elevation of the mixtur'etothe top of the heating chamber 1, the added coal is. dried and is partially heated, whereby it is in condition to flow .freely hoist mechanism,-where "it is is inoperation.

understood that the pro ortion of unheated coal that isadded may e varied in accordance with the condition of the unheated coal or with other operating conditions, in order to insure satisfactory and contmuous opera-- tion of the prheater. Economical operation of the prehc'ater wouldrequire that only such amount of 'coalbe re-circulated as is necessarylto insure that has a temperature sufiicient to preclude condensat-ion of moisture by the mixture.

The c ole of operations that have been describe continue so long as the preheater The treated coal that is withdrawn through the conveyor 8 is supplied to coke ovens or the like as desired and the sup- .ply 'to the conveyor 6 is added at substantialythe same rate. Y

I It will be noted th'at I have provided a preheater that may utilize gases of combustion without theemployment of large quantities of refr ctory material, suchtas' is usually P 553? lnvolve moderate temperature insures that the walls when gases of high temperature are relatively simple expedient of providing'initially an envelope of gases of ofthefiues will not be damaged.

the fines 1n such therebetween arev I tween the various rows whereby its passage through the heating chamber,

-The entire mechanism is substantially autobeing particularly adapted for the 1 ing of coal prior to its being su plie I have rovided, also, an arrangement of p manner and of such construction that the streams of coal flowing divided in such portions that an equalldistribution of the coal beof flues is insured substantially all of the coal is in contact with one or-more of the flues during matic, it bein necessary only to regulate the .amount of un eated coal to beaddedin acconnection with anyprocess wherein it is desired to heat. coal or other material. For

i of the heating cham .for supplying gases at example, it. may be pgssible to heat the flues r to such temperatures that carbonization or distillation of non-coking coal, shale or lignite may be accomplished during'itspassage therethrough. The foregoing and other'applications of my invention will occur to those familiar with apparatus of this general type.

, I claim as my invention:

1; In a heating. system, the combination with a passageway for heated gases, of meansdifferent tem eraturesv initially thereto, said gases being so dispose the mixture ofboth coals.

' than, said passageway perature gas that the hotter gas is surrounded by a layer of gas of lower temperature.

2. In a heating system, the, combination with a. passageway for heated ga'ses, of means for supplying gases at diflerent temperatures thereto, said gases I I that the hotter gas' is surrounded by a layer of gasof lower'temperature, said'means comprising a member having an opening in aline- -'but of smaller cross-section and said member being spaced from ne end of said passageway to provide ,an-o ening therebetween. I

'3. In a heatmgsystem, the combination with a pluality of passageways for heated gases, of means for supplying gases at different temperatures to each of said passageways, said gases being so disposed that at ment with,

the entrance of each of said passageways thev hotter gas 15 surrounded bya layer of gas of:

lower temperature.

4. In a heating system, with a plurality of passageways gases, of means for supplying gases at the combination for heated diiferent temperatures to each of said passage ways, said gases being so disposed that at the entrance of each ofsaid passageways the hotter gas is surroundedby a layer ofgas of lower temperature, said means comprising a structure having openings inalinement with, but of smaller cross-section'than, said passageways, and said structure being spaced from the ends of said passageways to provide openings communicating therewith.

5. In a heating system,

for supplying gas at relatively high temperature to said passageway, and means for supplying a layer of gas at relatively low tembetween the high temperature gas and the walls of said passageway at the entrance thereof.

6. The combination with a plurality of flues for gases and a plurality of sources of gas of difierent temperatures, of means for directing the flow of said gasesto said flues comprising a structure spaced from the ends of said flues to provide access of relatively low temperature gas to said flues at the peripheries thereof, said structure having alined openings of constricted cross-sectional area to admit relatively high temperature gas to the central portions of said flues.

- 7 In a, heating system, a plurality of "spaced'horizontal flues 1n staggered relation,

said flues having sloping top portions of different lengths whereby streams of material intermingled.

being so disposed initially the combination" with apassageway for heated gases. of means a 9. In a heatin system, a plurality of rows of spaced flues, t e'members of adjacent rows ing in staggered relation and said flues having sloping top portions of unequal lengths, the flues of ad acent rows being opposltely arranged with respect to sai top portions where y streams of material flowing downwardly between said flues are intermingled to insure that unheated material is 10 adjacent to said flues.

- 10. In a heating system, the combination with a plurality of flues and a source of gas at a relatively high tem erature, of means for returning a portion 0 the waste as from said flues at reduced temperature or mixture with the high temperature gas, and means for insuring a supply of the as of reduced tem erature for each of said ues com-- prising a oraminous structure spaced from the entrances of said flues, and means for con 7 ducting the waste gas between said structure and the entrances to said flues.

In testimony whereof, I have hereunto subscribed my name this 19th day of July 1927.

' FRANZ PUENIlIG.

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