CA1331917C - Method and a composition for providing an improved combustion in process of combustion containing hydrocarbon compounds - Google Patents
Method and a composition for providing an improved combustion in process of combustion containing hydrocarbon compoundsInfo
- Publication number
- CA1331917C CA1331917C CA000522898A CA522898A CA1331917C CA 1331917 C CA1331917 C CA 1331917C CA 000522898 A CA000522898 A CA 000522898A CA 522898 A CA522898 A CA 522898A CA 1331917 C CA1331917 C CA 1331917C
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- Canada
- Prior art keywords
- peroxide
- combustion
- hydrogen peroxide
- liquid
- liquid composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L10/00—Use of additives to fuels or fires for particular purposes
- C10L10/02—Use of additives to fuels or fires for particular purposes for reducing smoke development
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Liquid Carbonaceous Fuels (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
ABSTRACT
A method and a composition for providing an improved combus-tion in processes of combustion containing hydrocarbon compounds in order to reduce the content of injurious substances in the exhaust gases/discharges, at which a liquid composition containing 10-60 %. by volume of a peroxide or peroxo compound is added to the air of combustion or the fuel-air mixture respectively.
A method and a composition for providing an improved combus-tion in processes of combustion containing hydrocarbon compounds in order to reduce the content of injurious substances in the exhaust gases/discharges, at which a liquid composition containing 10-60 %. by volume of a peroxide or peroxo compound is added to the air of combustion or the fuel-air mixture respectively.
Description
-"~ 1331917 A METHOD AND A COMPOSITION FOR PROVIDING AN IMPROVED
COMBUSTION IN PROCESSES OF COMBUSTION CONTAINING HYDROCARBON
COMPOUNDS
TECHNICAL FIELD
The present invention relates to a method and a liquid composition which initiates and optimizes processes of combustion containing hydrocarbon compounds and thereby reduces the content of injurious substances in the exhaust gases or discharges.
BACXGROUND OF THE INVENTION
In recent years attention has been paid to environmental contamination and high energy consumption especially in view of the dramatically occurring forest death. Exhaust gases i have however always been a problem in population centers.
Despite continuously improved engines and heating techniques with less discharges or exhaust gases, the increasing numbers of vehicles and incineration plants have resulted in a total increase of the amount o exhaust gases.
The primary cause of impure exhaust gases and high energy consumption is insufficient combustion. The design of the consumption process, the efficiency of the ignition system, the quality of the fuel and the fuel-air mixture determines how effective the combustion becomes and how much uncombusted and dangerous substances the gases contain. Different teahniques are used for reducing the amount of such ;
substances, for example, recirculation systems and the well known catalyst techni~ue, which provides a combustion of the exhaust gases outside the actual combustion process.
: ~:
Combustion is the reaction of a substance with oxygen (2) with the generation of heat. Substances such as carbon (C), hydrogen gas (H2), hydrocarbon and sulphur (S) generate sufficient heat to maintain their combustion temperature ; ~
.'.1~" ' ' ~'' while, for example, nitrogen gas (N2) requires a supply of -heat to be oxidized.
At a high temperature, 1200-2500C and with sufficient amount of oxygen complete combustion is achieved, at which each substance takes up a maximum amount of oxygen. The end products are CO2 (carbon dioxide), H2O (water), SO2, and SO3 (sulphur oxides) and some NO and NO2 (nitrogen oxides, NOx).
The sulphur and nitrogen oxides are responsible for a great deal of the acidification of the environment, they are injurious to inhale and especially the later takes energy from the combustion process.
It is also possible to obtain cold flames, for example the blue, flattering flame from candle which is going out, where the temperature is only about 400C. The oxidation will then not be complete but the end products can be H22 (hydrogen peroxide), CO (carbon monoxide) and possibly C (soot). The two last mentioned substances are like NO injurious and can give off more energy at a complete combustion.
Petrol is a mixture of hydrocarbons from crude oil with a boiling point in the raise 40-200C. About 2000 different hydrocarbons with 4-9 carbons are present.
The detailed combustion process is very complicated even for simple substances. The fuel molecules are decomposed to smaller units, of which most are so called free radicals, i.e. unstable molecules which quickly react with for example oxygen.
The most important radicals are the oxygen atom O: the hydrogen atom H and the hydroxyl radical OH. The latter i5 of greatest importance for decomposing and oxidizing the fuel both through directly bonding to this and by removing hydrogen at which water is formed.
S ,~
....
^~ ~331917 3 ~
In the beginning of the initiation of the combustion water is formed from these according to the reaction HzO + M ~ H~ ~ OH ~ M ~;
where M is another molecule for example nitrogen or a wall or -~
a spark plug electrode surface which the water collides with.
Since water is a very stable molecule a high temperature is required for the decomposition to take place. The better alternative is to add hydrogen peroxide which is decomposed in a similar way:
H22 ~ M , 2 OH I M ~ ~ ;
This reaction takes place much easier and at a lower temparature, especially on surfaces at which the ignition o the fuel- air mixture occurs easier and in a more controlled way. A further positive effect of the reaction of a surface is that hydrogen peroxide ~asily reacts with soot and tar on walls and spark plugs to carbon dioxide (CO ~ which gives clean electrode surfaces and a better spark.;;~
If both hydrogen peroxide and water is added a drastic reduction of CO in the exhaust gases is provided according to the following~
COMBUSTION IN PROCESSES OF COMBUSTION CONTAINING HYDROCARBON
COMPOUNDS
TECHNICAL FIELD
The present invention relates to a method and a liquid composition which initiates and optimizes processes of combustion containing hydrocarbon compounds and thereby reduces the content of injurious substances in the exhaust gases or discharges.
BACXGROUND OF THE INVENTION
In recent years attention has been paid to environmental contamination and high energy consumption especially in view of the dramatically occurring forest death. Exhaust gases i have however always been a problem in population centers.
Despite continuously improved engines and heating techniques with less discharges or exhaust gases, the increasing numbers of vehicles and incineration plants have resulted in a total increase of the amount o exhaust gases.
The primary cause of impure exhaust gases and high energy consumption is insufficient combustion. The design of the consumption process, the efficiency of the ignition system, the quality of the fuel and the fuel-air mixture determines how effective the combustion becomes and how much uncombusted and dangerous substances the gases contain. Different teahniques are used for reducing the amount of such ;
substances, for example, recirculation systems and the well known catalyst techni~ue, which provides a combustion of the exhaust gases outside the actual combustion process.
: ~:
Combustion is the reaction of a substance with oxygen (2) with the generation of heat. Substances such as carbon (C), hydrogen gas (H2), hydrocarbon and sulphur (S) generate sufficient heat to maintain their combustion temperature ; ~
.'.1~" ' ' ~'' while, for example, nitrogen gas (N2) requires a supply of -heat to be oxidized.
At a high temperature, 1200-2500C and with sufficient amount of oxygen complete combustion is achieved, at which each substance takes up a maximum amount of oxygen. The end products are CO2 (carbon dioxide), H2O (water), SO2, and SO3 (sulphur oxides) and some NO and NO2 (nitrogen oxides, NOx).
The sulphur and nitrogen oxides are responsible for a great deal of the acidification of the environment, they are injurious to inhale and especially the later takes energy from the combustion process.
It is also possible to obtain cold flames, for example the blue, flattering flame from candle which is going out, where the temperature is only about 400C. The oxidation will then not be complete but the end products can be H22 (hydrogen peroxide), CO (carbon monoxide) and possibly C (soot). The two last mentioned substances are like NO injurious and can give off more energy at a complete combustion.
Petrol is a mixture of hydrocarbons from crude oil with a boiling point in the raise 40-200C. About 2000 different hydrocarbons with 4-9 carbons are present.
The detailed combustion process is very complicated even for simple substances. The fuel molecules are decomposed to smaller units, of which most are so called free radicals, i.e. unstable molecules which quickly react with for example oxygen.
The most important radicals are the oxygen atom O: the hydrogen atom H and the hydroxyl radical OH. The latter i5 of greatest importance for decomposing and oxidizing the fuel both through directly bonding to this and by removing hydrogen at which water is formed.
S ,~
....
^~ ~331917 3 ~
In the beginning of the initiation of the combustion water is formed from these according to the reaction HzO + M ~ H~ ~ OH ~ M ~;
where M is another molecule for example nitrogen or a wall or -~
a spark plug electrode surface which the water collides with.
Since water is a very stable molecule a high temperature is required for the decomposition to take place. The better alternative is to add hydrogen peroxide which is decomposed in a similar way:
H22 ~ M , 2 OH I M ~ ~ ;
This reaction takes place much easier and at a lower temparature, especially on surfaces at which the ignition o the fuel- air mixture occurs easier and in a more controlled way. A further positive effect of the reaction of a surface is that hydrogen peroxide ~asily reacts with soot and tar on walls and spark plugs to carbon dioxide (CO ~ which gives clean electrode surfaces and a better spark.;;~
If both hydrogen peroxide and water is added a drastic reduction of CO in the exhaust gases is provided according to the following~
2 CO2 ~ o initiation 2) O: ~ H20 ~ 2 OH branching ',".' ~''. ".
3) OH~ ~ CO ~ CO2 ~ H~ propagation ~ ~ ;
4~ H + 2 - ' OH~ ~ O: branching From the reaction 2) we can see that water plays a catalyzing role by later being reformed. Due to that hydrogen pero~ide gives a many thousand times higher contant of OH-radicals than watQr step 3) will be considerab].y accelerated and remove the P1393~.~C-20~.532-LE
~ ~3319~7 . ~ , most of C0 formed. By that additional energy is set free which helps to maintain the combustion.
N0 and N0 are very poisonous compounds, about four times as poisonous as carbon monoxide. At an acute poisoning the lung tissues are injured. N0 is a non-desired by-product at combustion. In the presence of water N0 is oxydized to HN03 and contributes in this form to about half of the acidification, the other half being caused by H250~. A problem is that NOx can dacompose o~one in the upper part of the atmosphere.
A great part of N0 comes from the reaction betwen the oxygen and nitrogen of the air at a high temperature and is there~ore independent of the composition of the fuel. How much NOx that is formed is besides dependant of during which conditions the ~-combustion takes place. If the temperature reduction can take place very slowly this leads to an equilibrum at moderate high temperatures and a lower final concantration of N0.
The following methods can be used for keeping the formation of N0 low 1. Combustion in two steps of a fuel rich mixture ~;
2. Low combustion temperature through a) high excess of air b~ strong cooling c) re-circulation of the cornbustion gases In the chemical analysis of flames it has often been observed that a concentration of N0 in the flame is much higher than after. There is a process which decomposes N0. A probable i , ., . " ~ .
reaction is:
CH3 . I N0 ~ . . . HfN ~ H20 :, ,.:
` ; N
.... . .
P13934~C-20~502-LE
, `~ ........................................................................ ..
Thus the formation of N2 is supported by conditions which give high concentrations of CH3, viz, a hot, fuel rich flame.
Fuels containing nitrogen, for example in the form of heterocyclic hydrocarbons like pyridine from experience gives -off more NO.
The content of N in different fuels (approximately):
10 - Crude oil 0.65%
- Ashphalt 2.30%
- Heavy oils 1.40%
- Light oils 0.07%
- Carbon 1- 2%
In SE-~-429.201 there is disclosed a liquid composition containing 1-10% by volume of hydrogen peroxide, at which the residual amount consists of water, aliphatic alcohol and lubricating oil and possibly a corrosion inhibitor, said liquid composition being supplied to the combustion air or the fuel-air mixture. At such low contents of hydrogen peroxide an insufficient amount of OH-radicals are formed for reaction both with the fuel and the CO formed. Besides there is no self-ignition of the fuel obtained, at which the ~;
improvement of the combustion which is achieved as compared to the addition of only water is small. ~ ;
In DE-A-2.362.082 there is described admixture of an ~ -oxidizing agent, for example hydrogen peroxide, in connection with combustion, however the hydrogen peroxide is decomposed to water and oxygen by means of a catalyst before it is supplied to the combustion air. ;
The present invention provides an improved combustion and by that a reduction of the discharge of injurious exhaust gases in connection with combustion processes , ~ ~1.,, . ~, : ~ 331 9~ 7 containing hydrocarbon compounds, by an improved initiation of the combustion and maintenance of an optimum and complete -combustion under so favourable conditions that the content of injurious exhaust gases is strongly reduced.
Accordingly therefore the present invention provides a method cf improving combustion to reduce the content of -injurious substances in the exhaust gases in processes involving the combllstion of hydrocarbon fuels in a combustion chamber, comprising the step of introducing directly into the combustion chamber, or a pre-chamber where ignition takes place associated therewith, and without prior mixing with the -fuel, a liquid composition containing at least lO and not more than 80~ by volume of peroxide or water-containing peroxo-compounds 50 as to supply OH radicals to the combustion gases.
... ..
Under alkaline conditions hydrogen peroxide is decomposed to hydroxyl radicals and superoxide ions according to H22 + HO2 ~ HO' + 2 + H2O
The hydroxyl radicals which are formed can on one hand react with themselves and on the other hand with the~i superoxide ions or with hydrogen peroxide. These reactions involve that in turn hydrogen peroxide, oxygen gas and hydroperoxide radicals are formed according to the following reaction formulas:
:``','~' ~
HO-~ HO- H22 .
HO + o~2 ~ 302 + OH
HO + H2O2 HO2-+ H2O
~ ` .
3 ~ 7 It is known that pKa for the hydroperoxide radical is 4.88 + 0.10, which means that all hydroperoxideradicals are dissociated to superoxide ions. Superoxide ions can also react with hydrogen peroxide, with themselves or act as catchers of :~
singlett oxygen formed.
2 + H22 b 2 + HO + OH ~ ;
2 + 2 + H20 ~ 102 + HO2 ~ OH :
' ~:' :,',~
- 6a -..
~J . .' ~ 2 ' 2 ~ 2' ~ 22 kcal .
Thus there is formed oxygen gas and hydroxyl radicals and singlett oxygan and hydrogen peroxide and triplett oxygen and an energy waist of 22 kcal. It has also proved that heavy metal jons present at the catalytic decomposition of hydrogen peroxide gives hydroxyl radicals and superoxid ions.
From what has been said and is known before the following knowledge about ths ccoefficients of velocity is presented, for example as follows with a typical alkane from petrol.
~ : .
The coefficients of velocity for attacking n-octane with H, O
and OH;
k=A exp~E/RT) ~ ~
: ~' ,:','~, ReactionA~cm /mol:s) E~kJ/mol) n-CnH18 ~ H7 1:1o1~ 35.3 1~ 19 . O , OH2.0 1o13 3.9 ::
From the example we can see that the attack from the OH-radical can take place quicker and at a lower temPeratUre than from H and 0.
The coefficients of velocity for CO t OH ~ C02 ~ H has an unusual temperature dependence through its negative activation energy and ~igh coefficient of temperature. It can be written 4.~ 10 T expl3,1/RT). The reaction velocity will then be almost constant about 101 cm /mol.s at temperatures lower than 1000 K, i.e. all the way down to room temperature. At higher temperature~ than 10000K the reaction velocity is ;
increased some times. Thanks to this this reaction is the completely dominating ~for converting CO to C02 at combustion :.-:: . .: .
P1393/.dC-2045E12-LE '.';~
" "' ' ~ '~ ~ ' : ::..:
1331917 a of hydrocarbons. The early and completa combustion of CO
improves by that the thermal efficiency.
An example illustrates the antagonism between O and OH are th~ reactions NH3-H2O2 -NO where and addition of H2Oz gives a 9OZ reduction of NOx in oxygen-free environment. If on the other hand O is present, even at only 2 Z, the NOx reduction is drastically detoriated.
For providing OH-radicals according to the invention H O is used which is dissociated at about 500C, They have a li,fe time of maximum 20ms.
At a normal combustion of ethanol 70 'Z. of the fuel is consumed by a reaction with OH-radicals and 30 Z with H-atoms. The invention which already at the initiation of the combustion supplies OH-radicals improves the combustion dramatically by immediately attacking the fuel. Oy adding a liquid composition with a high content of hydrogen peroxide ~over 10X) there is yet sufficient with OH-radicals for immediately oxidizing the CO formed. At lower contents of hydrogen peroxide there are not sufficient with OH-radicals formed for reacting both with the fuel and with the CO.
The liquid composition i5 supplied so that there will be no chemical reaction from the li~uid container to the combustion room, i.e. decomposition of hydrogen peroxide to water and oxygen gas will not take place but the liquid will in intact condition reach the combustion directly or alternatively to a prechamber were a mixture of the liquid and the fuel is ~ er ignited outside the actual combustion room.
If the concentration of hydrogen peroxide is suf~iciently high ~about 35 Z) a self-ignition of the fuel can take place as well as a maintainance o~ the combustion. The ignition of the liquid-fuel mixture can take place through self ignition or by contact with a catalyzing surface, at which spark plugs or the like are not r~quired. The ignition can also take place through ignition wit~ heat energy, for example a spark plug, :, , .: ,' ':
P1393~pC-20~5U2-LE
'''' ' ~33~91 7 glow body, open flame or the like.
Admixture of an aliphatic alcohol to hydrogen peroxide can initiate self-ignition. Fspecially in pre-chambersystems this can be desireble, at which the hydrogan peroxide and the alcohol may not be allowed to mix before they reach the pre-chamber.
~y arranging an injection valve for the liquid composition for each cylinder a very exact and for all service conditions adapted dosing of the liquid is provided. By means of a - -control unit which controls the inJection valves and a number of signal transmittors connected to the motor, which gives !`'~
signals to the control unit representing the position of the crank axel, motor speed and load and possibly also the temperature of the ingas, there is made possible a siequential injection and synchronization with the opening and closing of the injection valves and dosing of the liquid not only depend-ent on the load and desired power output, but also of the motorspeed and the temperature of the injection air, which gives a good runnability under all conditions. The liquid mixtura to a certain degree replaces air supply.
A number of comparative tests have been performed for finding out the differences in effect between water and hydrogen peroxide mixtures ~23- respectively 35 /.). The loads which were chosen correspond to driving on motor highways and in cities. The test motor was a P20E connected to a waterbrake.
The motor was warmed up before the tests started.
' ~, ...
At motor highway load the emisslons of NOx as well as CO and HC increased wh~n hydrogen peroxide was exchanged for water.
The contents of NOx were reduced with an increased amount of hydrogen peroxide. Also water reduced the NOx-contents, however at this load four times as much water as 23 Z hydrogen peroxida was required for achieving the same reduction of the NOx-contents. ~
:': ' ' :"::
In city-traffic load ~35 X. hydrogen peroxide was firstly .,: . . ::..
P13934~C-204502-LE
^` 13~1917 10 '.
supplied, at which the motorspeed and moment were somewhat ~-increased 120-30 RPM/0.5-1 Nm~
At a change to 23 X hydrogen peroxide the motorspeed and ~ -moment were decreased at the same time as the NOx-content was increased. When supplying pure water it was difficult to keep the motor running. The HC-content was strikingly incraased.
,,:, Thus the hydrogen peroxide improved the combustion at the same time as the NOx-contents were redjuced. Tests performed at the Swedish Motor-vehicle Inspectorate on a SAAB 900i and a Volvo 760 Turbo with and without a mixture to the fuel of a 35 X
hydrogen peroxide gava the following results with respect to ~.
the emission of CO, HC, NOx and C02. The percentage state the result obtained with a mixture of hydrogen peroxide in relation the result without a mixture.
: .
SAAB 900i ~
' . ..
Cold startinq Warm startinq Warm drivinq Idle runninq CO : -23 X CO : -54 X CO : -76 X CO : -90 X ;
HC : ~ 6 l HC : ~ O X HC : - 7 X. HC : -50 Z
NOx: -25 X NOx: -12 X NOx: -~3 /.
CO : ~33 X CO : ~ 4 X CO : ~ 5 X
HCD ~road drivinql , CO : -41 X
~C : ~ 8 X
NOx: -15 X
C02: ~ 3 X
','~ '. ' ' "~ ' "' P13934~C-2045B2-LE
~ ~ 331917 "
. . .
VOLVO 760 Turbo Idle runninq Warm drivin CO : -73 X CO : -54.3 /.
HC : -18 Z HC : - 2.3 X
NOx: -21 Z NOx: - 8.3 /. ,-At tests performed with a Volvo 245 GE 4FK/~4 the car had at idle running a CO-content of 4 Z and a HC-content of 65 ppm without pulse air ~exhaust gas cleaning). With the admixture of a 35 /. solution of hydrogen peroxide the CO-content was reduced to 0.05 X and the HC-content to 10 ppm. The ignition timing was 10 and the idling R.P.M. was 950 in both cases.
- , At tests performed by the Norwegian Marine Technichal Research Institute A/S in Trondheim the emission of HC, CO and NOx was examined for a Volvo 760 Turbo after ECE-Regulation No. 15,03 with warm engine at starting with and without a mixture of a 35 X solution of hydrogen peroxide to the combustion.
Test results:
ECE 15~03 Idle runninq `~
HC 4.3 g/test 340 ppm Without hYdrogen peroxide CO 70 gltest 0.64 Z
Nox 4.~ g/test 92 ppm ;'': .'''"". ~
With admixture o~ a 35 X HC 4.2 g/test 2~0 ppm ~-solution of hydrogen per- CO 32 g/test 0.17 Z
oxide NOx 4.4 g/test 73 ppm ~-': :' ' ,..
Only the use of hydrogen peroxide has been mentioned above. It ~ -can however be assumed that a corresponding effect is ;
achieved also with other peroxides and peroxo compounds inorganic a~ well as organic.
P13934~C-2045~2-EE
~3~1917 12 The liquid composition can besides peroxide and water also contain up to 70 X of an aliphatic alcohol with 1-~ carbons and up to 5 X of an oil containing a corrosion inhibitor.
. ~ .
The amount of a miKture of the liquid composition to the fuel can very from same tenth part of a percent liquid composition per amount of fuel up to some hundred ~/.. The higher amounts are used i.a. for fuels which are difficult to ignite.
:
The liquid composition is intended to be used in combustion engines and other combustion processes containing hydrocarbon compounds like oil, coal, biomass etc. in combustion furnaces for providing a more complete combustion and a reduction of the contents of injurious substances in the discharges.
. ;'' ; ''-.::
P13934~C-204582-LE
~ ~3319~7 . ~ , most of C0 formed. By that additional energy is set free which helps to maintain the combustion.
N0 and N0 are very poisonous compounds, about four times as poisonous as carbon monoxide. At an acute poisoning the lung tissues are injured. N0 is a non-desired by-product at combustion. In the presence of water N0 is oxydized to HN03 and contributes in this form to about half of the acidification, the other half being caused by H250~. A problem is that NOx can dacompose o~one in the upper part of the atmosphere.
A great part of N0 comes from the reaction betwen the oxygen and nitrogen of the air at a high temperature and is there~ore independent of the composition of the fuel. How much NOx that is formed is besides dependant of during which conditions the ~-combustion takes place. If the temperature reduction can take place very slowly this leads to an equilibrum at moderate high temperatures and a lower final concantration of N0.
The following methods can be used for keeping the formation of N0 low 1. Combustion in two steps of a fuel rich mixture ~;
2. Low combustion temperature through a) high excess of air b~ strong cooling c) re-circulation of the cornbustion gases In the chemical analysis of flames it has often been observed that a concentration of N0 in the flame is much higher than after. There is a process which decomposes N0. A probable i , ., . " ~ .
reaction is:
CH3 . I N0 ~ . . . HfN ~ H20 :, ,.:
` ; N
.... . .
P13934~C-20~502-LE
, `~ ........................................................................ ..
Thus the formation of N2 is supported by conditions which give high concentrations of CH3, viz, a hot, fuel rich flame.
Fuels containing nitrogen, for example in the form of heterocyclic hydrocarbons like pyridine from experience gives -off more NO.
The content of N in different fuels (approximately):
10 - Crude oil 0.65%
- Ashphalt 2.30%
- Heavy oils 1.40%
- Light oils 0.07%
- Carbon 1- 2%
In SE-~-429.201 there is disclosed a liquid composition containing 1-10% by volume of hydrogen peroxide, at which the residual amount consists of water, aliphatic alcohol and lubricating oil and possibly a corrosion inhibitor, said liquid composition being supplied to the combustion air or the fuel-air mixture. At such low contents of hydrogen peroxide an insufficient amount of OH-radicals are formed for reaction both with the fuel and the CO formed. Besides there is no self-ignition of the fuel obtained, at which the ~;
improvement of the combustion which is achieved as compared to the addition of only water is small. ~ ;
In DE-A-2.362.082 there is described admixture of an ~ -oxidizing agent, for example hydrogen peroxide, in connection with combustion, however the hydrogen peroxide is decomposed to water and oxygen by means of a catalyst before it is supplied to the combustion air. ;
The present invention provides an improved combustion and by that a reduction of the discharge of injurious exhaust gases in connection with combustion processes , ~ ~1.,, . ~, : ~ 331 9~ 7 containing hydrocarbon compounds, by an improved initiation of the combustion and maintenance of an optimum and complete -combustion under so favourable conditions that the content of injurious exhaust gases is strongly reduced.
Accordingly therefore the present invention provides a method cf improving combustion to reduce the content of -injurious substances in the exhaust gases in processes involving the combllstion of hydrocarbon fuels in a combustion chamber, comprising the step of introducing directly into the combustion chamber, or a pre-chamber where ignition takes place associated therewith, and without prior mixing with the -fuel, a liquid composition containing at least lO and not more than 80~ by volume of peroxide or water-containing peroxo-compounds 50 as to supply OH radicals to the combustion gases.
... ..
Under alkaline conditions hydrogen peroxide is decomposed to hydroxyl radicals and superoxide ions according to H22 + HO2 ~ HO' + 2 + H2O
The hydroxyl radicals which are formed can on one hand react with themselves and on the other hand with the~i superoxide ions or with hydrogen peroxide. These reactions involve that in turn hydrogen peroxide, oxygen gas and hydroperoxide radicals are formed according to the following reaction formulas:
:``','~' ~
HO-~ HO- H22 .
HO + o~2 ~ 302 + OH
HO + H2O2 HO2-+ H2O
~ ` .
3 ~ 7 It is known that pKa for the hydroperoxide radical is 4.88 + 0.10, which means that all hydroperoxideradicals are dissociated to superoxide ions. Superoxide ions can also react with hydrogen peroxide, with themselves or act as catchers of :~
singlett oxygen formed.
2 + H22 b 2 + HO + OH ~ ;
2 + 2 + H20 ~ 102 + HO2 ~ OH :
' ~:' :,',~
- 6a -..
~J . .' ~ 2 ' 2 ~ 2' ~ 22 kcal .
Thus there is formed oxygen gas and hydroxyl radicals and singlett oxygan and hydrogen peroxide and triplett oxygen and an energy waist of 22 kcal. It has also proved that heavy metal jons present at the catalytic decomposition of hydrogen peroxide gives hydroxyl radicals and superoxid ions.
From what has been said and is known before the following knowledge about ths ccoefficients of velocity is presented, for example as follows with a typical alkane from petrol.
~ : .
The coefficients of velocity for attacking n-octane with H, O
and OH;
k=A exp~E/RT) ~ ~
: ~' ,:','~, ReactionA~cm /mol:s) E~kJ/mol) n-CnH18 ~ H7 1:1o1~ 35.3 1~ 19 . O , OH2.0 1o13 3.9 ::
From the example we can see that the attack from the OH-radical can take place quicker and at a lower temPeratUre than from H and 0.
The coefficients of velocity for CO t OH ~ C02 ~ H has an unusual temperature dependence through its negative activation energy and ~igh coefficient of temperature. It can be written 4.~ 10 T expl3,1/RT). The reaction velocity will then be almost constant about 101 cm /mol.s at temperatures lower than 1000 K, i.e. all the way down to room temperature. At higher temperature~ than 10000K the reaction velocity is ;
increased some times. Thanks to this this reaction is the completely dominating ~for converting CO to C02 at combustion :.-:: . .: .
P1393/.dC-2045E12-LE '.';~
" "' ' ~ '~ ~ ' : ::..:
1331917 a of hydrocarbons. The early and completa combustion of CO
improves by that the thermal efficiency.
An example illustrates the antagonism between O and OH are th~ reactions NH3-H2O2 -NO where and addition of H2Oz gives a 9OZ reduction of NOx in oxygen-free environment. If on the other hand O is present, even at only 2 Z, the NOx reduction is drastically detoriated.
For providing OH-radicals according to the invention H O is used which is dissociated at about 500C, They have a li,fe time of maximum 20ms.
At a normal combustion of ethanol 70 'Z. of the fuel is consumed by a reaction with OH-radicals and 30 Z with H-atoms. The invention which already at the initiation of the combustion supplies OH-radicals improves the combustion dramatically by immediately attacking the fuel. Oy adding a liquid composition with a high content of hydrogen peroxide ~over 10X) there is yet sufficient with OH-radicals for immediately oxidizing the CO formed. At lower contents of hydrogen peroxide there are not sufficient with OH-radicals formed for reacting both with the fuel and with the CO.
The liquid composition i5 supplied so that there will be no chemical reaction from the li~uid container to the combustion room, i.e. decomposition of hydrogen peroxide to water and oxygen gas will not take place but the liquid will in intact condition reach the combustion directly or alternatively to a prechamber were a mixture of the liquid and the fuel is ~ er ignited outside the actual combustion room.
If the concentration of hydrogen peroxide is suf~iciently high ~about 35 Z) a self-ignition of the fuel can take place as well as a maintainance o~ the combustion. The ignition of the liquid-fuel mixture can take place through self ignition or by contact with a catalyzing surface, at which spark plugs or the like are not r~quired. The ignition can also take place through ignition wit~ heat energy, for example a spark plug, :, , .: ,' ':
P1393~pC-20~5U2-LE
'''' ' ~33~91 7 glow body, open flame or the like.
Admixture of an aliphatic alcohol to hydrogen peroxide can initiate self-ignition. Fspecially in pre-chambersystems this can be desireble, at which the hydrogan peroxide and the alcohol may not be allowed to mix before they reach the pre-chamber.
~y arranging an injection valve for the liquid composition for each cylinder a very exact and for all service conditions adapted dosing of the liquid is provided. By means of a - -control unit which controls the inJection valves and a number of signal transmittors connected to the motor, which gives !`'~
signals to the control unit representing the position of the crank axel, motor speed and load and possibly also the temperature of the ingas, there is made possible a siequential injection and synchronization with the opening and closing of the injection valves and dosing of the liquid not only depend-ent on the load and desired power output, but also of the motorspeed and the temperature of the injection air, which gives a good runnability under all conditions. The liquid mixtura to a certain degree replaces air supply.
A number of comparative tests have been performed for finding out the differences in effect between water and hydrogen peroxide mixtures ~23- respectively 35 /.). The loads which were chosen correspond to driving on motor highways and in cities. The test motor was a P20E connected to a waterbrake.
The motor was warmed up before the tests started.
' ~, ...
At motor highway load the emisslons of NOx as well as CO and HC increased wh~n hydrogen peroxide was exchanged for water.
The contents of NOx were reduced with an increased amount of hydrogen peroxide. Also water reduced the NOx-contents, however at this load four times as much water as 23 Z hydrogen peroxida was required for achieving the same reduction of the NOx-contents. ~
:': ' ' :"::
In city-traffic load ~35 X. hydrogen peroxide was firstly .,: . . ::..
P13934~C-204502-LE
^` 13~1917 10 '.
supplied, at which the motorspeed and moment were somewhat ~-increased 120-30 RPM/0.5-1 Nm~
At a change to 23 X hydrogen peroxide the motorspeed and ~ -moment were decreased at the same time as the NOx-content was increased. When supplying pure water it was difficult to keep the motor running. The HC-content was strikingly incraased.
,,:, Thus the hydrogen peroxide improved the combustion at the same time as the NOx-contents were redjuced. Tests performed at the Swedish Motor-vehicle Inspectorate on a SAAB 900i and a Volvo 760 Turbo with and without a mixture to the fuel of a 35 X
hydrogen peroxide gava the following results with respect to ~.
the emission of CO, HC, NOx and C02. The percentage state the result obtained with a mixture of hydrogen peroxide in relation the result without a mixture.
: .
SAAB 900i ~
' . ..
Cold startinq Warm startinq Warm drivinq Idle runninq CO : -23 X CO : -54 X CO : -76 X CO : -90 X ;
HC : ~ 6 l HC : ~ O X HC : - 7 X. HC : -50 Z
NOx: -25 X NOx: -12 X NOx: -~3 /.
CO : ~33 X CO : ~ 4 X CO : ~ 5 X
HCD ~road drivinql , CO : -41 X
~C : ~ 8 X
NOx: -15 X
C02: ~ 3 X
','~ '. ' ' "~ ' "' P13934~C-2045B2-LE
~ ~ 331917 "
. . .
VOLVO 760 Turbo Idle runninq Warm drivin CO : -73 X CO : -54.3 /.
HC : -18 Z HC : - 2.3 X
NOx: -21 Z NOx: - 8.3 /. ,-At tests performed with a Volvo 245 GE 4FK/~4 the car had at idle running a CO-content of 4 Z and a HC-content of 65 ppm without pulse air ~exhaust gas cleaning). With the admixture of a 35 /. solution of hydrogen peroxide the CO-content was reduced to 0.05 X and the HC-content to 10 ppm. The ignition timing was 10 and the idling R.P.M. was 950 in both cases.
- , At tests performed by the Norwegian Marine Technichal Research Institute A/S in Trondheim the emission of HC, CO and NOx was examined for a Volvo 760 Turbo after ECE-Regulation No. 15,03 with warm engine at starting with and without a mixture of a 35 X solution of hydrogen peroxide to the combustion.
Test results:
ECE 15~03 Idle runninq `~
HC 4.3 g/test 340 ppm Without hYdrogen peroxide CO 70 gltest 0.64 Z
Nox 4.~ g/test 92 ppm ;'': .'''"". ~
With admixture o~ a 35 X HC 4.2 g/test 2~0 ppm ~-solution of hydrogen per- CO 32 g/test 0.17 Z
oxide NOx 4.4 g/test 73 ppm ~-': :' ' ,..
Only the use of hydrogen peroxide has been mentioned above. It ~ -can however be assumed that a corresponding effect is ;
achieved also with other peroxides and peroxo compounds inorganic a~ well as organic.
P13934~C-2045~2-EE
~3~1917 12 The liquid composition can besides peroxide and water also contain up to 70 X of an aliphatic alcohol with 1-~ carbons and up to 5 X of an oil containing a corrosion inhibitor.
. ~ .
The amount of a miKture of the liquid composition to the fuel can very from same tenth part of a percent liquid composition per amount of fuel up to some hundred ~/.. The higher amounts are used i.a. for fuels which are difficult to ignite.
:
The liquid composition is intended to be used in combustion engines and other combustion processes containing hydrocarbon compounds like oil, coal, biomass etc. in combustion furnaces for providing a more complete combustion and a reduction of the contents of injurious substances in the discharges.
. ;'' ; ''-.::
P13934~C-204582-LE
Claims (18)
1. A method of improving combustion to reduce the content of injurious substances in the exhaust gases in processes involving the combustion of hydrocarbon fuels in a combustion chamber, comprising the step of introducing directly into the combustion chamber, or a pre-chamber where ignition takes place associated therewith, and without prior mixing with the fuel, a liquid composition containing at least 10 and not more than 80% by volume of peroxide or water-containing peroxo-compounds so as to supply OH radicals to the combustion gases.
2. A method as claimed in claim 1, wherein an aliphatic alcohol with 1-8 carbons is separately introduced into the combustion chamber or pre-chamber such that on mixing with the liquid composition self ignition takes place.
3. A method according to claim 1, wherein said liquid is an aqueous liquid.
4. A method as claimed in claim 3, wherein said liquid composition contains up to 70% of an aliphatic alcohol with 1-8 carbons.
5. A method according to claim 3, wherein said liquid contains up to 5% of an oil containing a corrosion inhibitor.
6. A method as claimed in claim 3, wherein said liquid contains at least 30% peroxide or peroxo compound.
7. A method as claimed in claim 3, wherein said peroxide is hydrogen peroxide.
8. A method according to claim 4, wherein said liquid contains up to 5% of an oil containing a corrosion inhibitor.
9. A method as claimed in claim 4, wherein said liquid contains at least 30% peroxide or peroxo compound.
10. A method as claimed in claim 5, wherein said liquid contains at least 30% peroxide or peroxo compound.
11. A method as claimed in claim 4, wherein said peroxide is hydrogen peroxide.
12. A method as claimed in claim 5, wherein said peroxide is hydrogen peroxide.
13. A method as claimed in claim 6, wherein said peroxide is hydrogen peroxide.
14. A method as claimed in claim 1, wherein said liquid composition comprises water, said peroxide or peroxo compound, up to 70% of an aliphatic alcohol with 1-8 carbons and up to 5% of an oil containing a corrosion inhibitor.
15. A method as claimed in claim 14, wherein said peroxide is hydrogen peroxide.
16. A method as claimed in claim 15, wherein said liquid composition contains at least 30% peroxide.
17. A method as claimed in claim 3, wherein said liquid composition contains at least 23% peroxide.
18. A method as claimed in claim 1, wherein said liquid contains at least 23% peroxide.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DD86296213A DD250714A5 (en) | 1986-11-12 | 1986-11-12 | METHOD AND COMPOSITION FOR IMPROVING COMBUSTION OF BURNING HYDROCARBON CONNECTIONS |
| CA000522898A CA1331917C (en) | 1986-11-12 | 1986-11-13 | Method and a composition for providing an improved combustion in process of combustion containing hydrocarbon compounds |
| HU864704A HU206740B (en) | 1986-11-12 | 1986-11-14 | Hydrocarbone containing materials for improving burning processes |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DD86296213A DD250714A5 (en) | 1986-11-12 | 1986-11-12 | METHOD AND COMPOSITION FOR IMPROVING COMBUSTION OF BURNING HYDROCARBON CONNECTIONS |
| CA000522898A CA1331917C (en) | 1986-11-12 | 1986-11-13 | Method and a composition for providing an improved combustion in process of combustion containing hydrocarbon compounds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1331917C true CA1331917C (en) | 1994-09-13 |
Family
ID=25671156
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000522898A Expired - Fee Related CA1331917C (en) | 1986-11-12 | 1986-11-13 | Method and a composition for providing an improved combustion in process of combustion containing hydrocarbon compounds |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1331917C (en) |
| DD (1) | DD250714A5 (en) |
| HU (1) | HU206740B (en) |
-
1986
- 1986-11-12 DD DD86296213A patent/DD250714A5/en not_active IP Right Cessation
- 1986-11-13 CA CA000522898A patent/CA1331917C/en not_active Expired - Fee Related
- 1986-11-14 HU HU864704A patent/HU206740B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| HU206740B (en) | 1992-12-28 |
| HUT45089A (en) | 1988-05-30 |
| DD250714A5 (en) | 1987-10-21 |
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