GB2252967A

GB2252967A - Effluent removal from combusted fuel off-gases downstream of combustion with injected sorbents

Info

Publication number: GB2252967A
Application number: GB9121602A
Authority: GB
Inventors: Domingo Rodriguez; Cebers Octavio Gomez
Original assignee: Intevep SA
Current assignee: Intevep SA
Priority date: 1991-02-19
Filing date: 1991-10-11
Publication date: 1992-08-26
Anticipated expiration: 2011-10-11
Also published as: DK170891A; KR940006397B1; NL9200310A; BR9104514A; IT1250357B; GB9121602D0; KR920016129A; DE4204795C2; ITTO910955A1; CA2053965A1; FR2672817A1; ITTO910955A0; JPH0596128A; DE4204795A1; DK170891D0; GB2252967B

Abstract

Removing effluents from off-gases generated by the combustion of a hydrocarbon fuel wherein an effluent sorbent is injected in the form of a spray of a liquid solution, slurry or dry solid into the off-gas stream downstream of the combustion zone at a controlled off-gas stream temperature. The effluent sorbent may be a calcium compound, magnesium compound or both and may be used with a promoter selected from the group consisting of iron, copper, manganese, boron, aluminium, sodium, potassium, zinc, nickel compounds and mixtures thereof.

Description

-1

BACKGROUND OF THE INVENTION

The present invention relates to a process for removing effluents from off-gases generated by the combustion of a hydrocarbon fuel and, more particularly, a process for removing the effluents wherein an effluent sorbent is injected into the off-gases downstream of the combustion zone.

Co-pending Application Serial Number 498,952, filed March 26, 1990, of which the instant application is a continuation-in-part, discloses a process for the in-situ production of a sorbent-oxide aerosol used for removing effluents from a gaseous combustion stream. In accordance with the process of U.S. Patent Application Serial No. 498,952 an aqueous solution comprising an effluent sorbent compound dissolved in water is admixed with a hydrocarbon containing fuel so as to form a combustible fuel mixture. The combustible fuel mixture is atomized and fed to a combustion zone wherein the atomized fuel mixture is combusted under controlled conditions to a temperature of greater than or equal to 14000K in the presence of an oxidant. During the combustion of the atomized fuel mixture at the temperature indicated above, a sorbent-oxide aerosol is produced which comprises ultra-fine sorbent-oxide particles having a mean diameter of submicron size in CIO-181 the gaseous combustion -stream. The gaseous combustion stream is thereafter cooled to a temperature of between 7000K to about 13500K so that the sorbent-oxide particles absorb the effluents from the gaseous combustion stream. The process of U.S. Patent Application Serial Number 498,952 has proved to be particularly useful for removing sulfur from combuqtion gas streams.

U.S. Patent 4,824,441 (1989) discloses a process comprising physically mixing calcium based sorbents with coal and additives, all pressed in the form of pellets, and burning the pellets in a boiler. It is well documented in the literature that physical mixing of solid additives does not provide effective SO 2 removal. The injection of Ca or Mg carbonate, oxide or hydroxide through the boiler flame is detrimental for t1he SO 2 capture reaction. U.S. Patent 4,191,115 (1980) discloses the use of promoters to enhance sulfation of limestone at 900C. By using low temperatures for sulfation of the limestone, detrimental effects such as sintering and loss of surface area are avoided, but the kinetics are slow as 64% of sorbent sulfation requires three hours. The '115 patent shows that physical mixing of the solid sorbent and promoter is riot an effective procedure.

90-181 Japanese Patent 78-39965 also uses a process which comprises physical mixing of sorbent and promoters. The patent fails to clearly disclose sorbent injection temperatures and sorbent to acid gas ratios which are key issues to a successful process. Japanese Patent 84-90169 also uses a process which comprises physical mixing of a sorbent and sulfation promoter. The calcium to sulfur molar ratio used is about 5. The calcium utilization obtained by the process is in the order of 10% which is very low.

Naturally, it would be highly desirable to develop new and improved processes for removing effluents from hydrocarbon fuel combustion gas streams which are economic to use and efficient in effluent reduction.

The process of the present invention represents an improvement over the processes described above because by using sorben-t- injection downstream of the flame, the best temperature for a given sorbent sulfation can be obtained and by using water solutions of the promoter salts a better contact between the sorbent and the promoter can be insured. Another feature of sorbent injection downstream of the flame is that it tends to be a process which is fuel independent as the sorbent only contacts the flue gases. The downstream injection of sorbent solutions or slurries also allows a close --)f, - go- 181 control on the required mixing between the sorbent and the SO 2 effluent which results in better sorbent utilization.

Accordingly, it is a principle object of the present invention to provide a process for removing environmental harmful effluents from a gaseous stream.

It is a particular object of the present invention to provide a process for the removal of effluents from a gaseous combustion stream wherein an effluent sorbent is injected into the combustion gas stream downstream of the combustion zone.

Further objects and advantages of the present invention will appear hereinbelow.

SUMMARY OF THE INVENTION

In accordance with the present invention, the Loregoing objects and advantages are readily obtained.

The present invention is drawn to a process for removing effluents from off-gases generated by the combustion of a hydrocarbon fuel or any other sulfur bearing fuel, gas or solid. The process of the present inverition comprises combusting a hydrocarbon fuel in a combustion zone at a preferred temperature and thereafter transporting the off-gases generated from the combustion of the fuel away from the combustion zone.

90-181 During the transportation of the off-gases, the off-gases are cooled to a controlled temperature range which is less than the combustion temperature. An effluent sorbent is injected into the off-gas stream at a controlled temperature downstream of the combustion zone. During the injection of the effluent sorbent at the controlled offgas stream temperature, the sorbent absorbs effluents from the off-gases.

In a preferred embodiment of the present invention, the effluent sorbent is spiked with a promoter which enhances the effect of the effluent sorbent on removing effluents from the off-gases. In accordance with the present invention, the effluent sorbent may be dissolved in water together with the promoter to form an aqueous solution which is injected into the off-gas stream. in this embodiment of the present invention the effluent sorbent solution is injected in a manner so as to pr,Gduce a fine spray wherein the average particle size is less than 100 microns, preferably less than 50 microns.

In an alternative embodiment of the present invention, the sorbent may be spiked with the promoter and fed in a dry manner into the off-gas stream. In this embodiment of the present invention the average particle size of the spiked sorbent should be less than or equal to 50 microns, preferably less than 10 microns.

90-181 In another alternative embodiment of the present invention, the sorbent is a finely divided water insoluble solid compound and the promoter is in the form of a water soluble compound. The effluent promoted sorbent is prepared by dissolving the promoter in water, to which solution the solid sorbent is added in such a way as to produce a slurry or suspension with a solid load of 50 wt.% or less. The effluent sorbent slurry is injected into the off-gas stream in a controlled manner so as to produce a fine spray wherein the average particle size is less than 100 microns, preferably less than 50 microns. In this embodiment of the present invention the average size of the solid sorbent should be less than or equal to 50 microns, preferably less than 10 microns.

The solubility of the promoter in water can be enhanced according to methods known to those skilled in the art, such as the use of chelating agents, legends, etc.

The most desired sorbents used in the process of the present invention include magnesium and calcium compounds and mixtures thereof. Suitable promoters include iron, copper, manganese, boron, aluminum, sodium, potassium, zinc and nickel compounds and mixtures thereof with iron, copper, manganese and boron 1-7 - 90-181 being preferred and iron and copper being ideal. The molar ratio of sorbent to effluent and the molar ratio of promoter to sorbent is dependent on whether a water soluable or insoluable sorbent is employed.

The process of the present invention offers an effective and economic mechanism for removing effluents from a combustion gas stream. The effectiveness of the process of the present invention will be made clear hereinbelow from a reading of the detailed description

DETAILED DESCRIPTION

The present invention is drawn to a process for removing effluents from off-gases generated by the combustion of a hydrocarbon fuel and, more particularly, a process as aforesaid wherein an effluent sorbent is injected in the form of a spray of a liquid solution, slurry or dry solid into the off-gas stream downstream of the combustion zone at a controlled off-gas stream temperature.

As noted above, tne process of the present invention comprises the steps of injecting an effluent sorbent into an offaas stream downstream of a combustion zone when the off-gas stream is at a critical temperature range. In accordance with a preferred embodiment of the present invention, the effluent 90-181 sorbent is mixed with a promoter and injected into the off-gas stream. In one embodiment of the process of the present invention the effluent sorbent is mixed with water and the promoter so as to form an aqueous effluent sorbent mixture. The effluent sorbent may be either water soluable or water insoluable. The mixture is thereafter injected into the off-gas stream under controlled conditions at a desired off-gas stream temperature. The effluent sorbent mixture is injected in a controlled manner so as to produce a fine spray having an average droplet size of less than or equal to 100 microns, preferably less than 50 um. The particle size of the sorbent remaining after a solution spray droplet has evaporated in the hot gas depends on the particle size of the droplet. It has been found that the smaller the sorbent particle the better the sulfation extent. Therefore the finer the mixture spray injected the better. In an alternative embodiment of the present invention the effluent sorbent is spiked with the promoter and injected into the off- gas stream in dry form. The particular way to spike a water insoluble sorbent with a promoter depends in part on the nature of both the sorbent and the promoter. For the preparation of promoter spiked calcium hydroxide Ca(OW 2 the procedure is as follows. Calcium 90-181 hydroxide can be easily prepared by adding hydration water to calcium oxide, Cao (best known as lime). The promoter can easily be incorporated into the calcium hydroxide structure by first dissolving a water soluble promoter compound in the hydration water and then making the hydration by mixing the sorbent solution and the calcium oxide together. The mixture then is heated to dryness or the hydration water is added in such amount that the final product is dry. In this embodiment of the present invention the average particle size of the effluent sorbent is less than or equal to 50 microns, preferably less than 10 microns.

Another alternative embodiment of the present invention involves the injection into the off-gas stream of a spray of the sorbent slurry. In this particular case the promoter is dissolved in the slurry water when the spray droplets are injected into the hot of.4-gas stream, water evaporates leaving behind the promoter as a coating on the sorbent solid particles. Further heating provides good sorbent-solid interreaction through sorbent-solid diffusion mechanisms. Wetting agents could be used to improve the sorbent/promoter contact.

As noted above, the effluent sorbent with or without promoter is injected into the off-gas stream when the off-gas stream is at a desired temperature - ID -- 90-181 T 2 The temperature T 2 depends on the metal used as a sorbent, and for a given metal T 2 also depends on the metal compound used. For a given metal the upper limit temperature for T 2 is dictated by the thermodynamic stability of the metal sulfate formed. The lower temperature limit for T 2 is related to sulfation kinetics. For the calcium based sorbents, it has been found in accordance with the present invention that the desired temperature of the off-gas stream at which temperature the sorbent will react with the effluent gases to form the corresponding solid sulfate should be elected according to the type of sorbent used, as follows: a) for water soluble sorbent compounds T 2 temperatures of about 1650F (900'C) to 2000'F (1093'C) are preferred when no promoter is present. When the promoter is present the upper temperature limit T 2 is increased to 2800OF thus the preferred range in this case is from 2000 to 2800'F. b) for water unsoluble promoted calcium sorbents (dry or slurry injection of calcium oxide, hydroxide or carbonate) the practical T 2 temperature is between 1650OF and 2200OF (12040C) and preferably between 1800OF (982C) and 2200'F.

90-181 It has been found in accordance with the preferred features of the present invention that the molar ratio of the promoted sorbent to the effluent (for example Ca/S) are as follows: 1) For water soluble sorbent compounds, a ratio of 0.4 to 1.2, preferably 0.6 to 1.0. 2) For dry solid injection or slurried sorbents, a ratio of 0.5 to 2.5, preferably 0.8 to 2-0. The molar ratio of promoter to sorbent used is from 0.01 to 0.15 and preferably between 0.01 to 0.05 for water soluble sorbents and 0.01 to 0. 10 for dry or slurry sorbent injection. The effluent sorbent compound may be selected from the group of elements consisting of alkaline, alkaline earth or other metal salts wherein the metals have the same or higher valence than the alkaline earth metals. The preferred effluent sorbents are calcium and magnesium with calcium being ideal. The promoter employed in the process of the present invention includes metals selected from the group consisting of iron, copper, manganese, boron, aluminum, sodium, potassium, zinc, nickel and mixtures thereof. Preferred promoters are iron, copper, manganese and boron with iron and copper being the most preferred.

In accordance with the present invention the effluent sorbent with or without promoter may be -[R - 90-181 injected into the off-gas stream in the presence of an oxidant. When the effluent sorbent is injected into the off-gas stream with an oxidant, it is preferred that oxidant be present in such amount as to provide a fine sorbent spray.

The following examples illustrate specific features of the process of the present invention but are in no way intended to be limiting.

EXAMPLE I

In order to demonstrate and quantify the existence of unwanted effluents, particularly, sulfur, in a hydrocarbon combustion stream a liquid hydrocarbon having a sulfur content of 3.8% by weight was mixed with water so as to obtain a mixture of 55% by volume hydrocarbon fuel and 45% by volume water. The mixture was thereafter combusted to completion. The fuel mixture was fed to the furnace -,,,rough a commercial nozzle. The fuel was atomized with air in a mass ratio of air to hydrocarbon fuel of up to 1.1 of t-e stoichiometric requirement. The hydrocarbon fuel was combusted at a firing rate of 56000 BTU/h unti1 completely combusted. The concentration of So 2 in the dry emission gases were measured and the concent-tation of SO 2 was found to be 2700 ppm. By dry emission A) - gases is meant all the gases produced during the combustion process, with the exception of H 2 01 corrected to 0% oxygen.

90-181 EXAMPLE 11

In order to demonstrate the effectiveness of the process of the present invention the liquid hydrocarbon employed in Example I was combusted under the same conditions set forth in Example I. The off-gases from the combustion zone were carried off and cooled to a temperature of 22000 F. An aqueous solution of calcium formate was injected into the off-gases at the temperature of 22000 F. The molar ratio of calcium formate injected into the off-gas stream to sulfur in the fuel combusted was 1.0. After injection of the aqueous solution of calcium formate into the off-gas stream the SO 2 concentration and the dry emission gases were measured and were found to be 1620 ppm. This level of so 2 represents a 40% reduction in SO 2 as compared to Example I. The amount of sorbent utilized is 40%. Sorbent utilization is defined as follows:

sorbent Ceffluentlbaseline - Ceffluent]sorbent utilized 100 x EeffluentIbaseline 1 moles sorbent 3 moles effluent -11+ - 90-181 Where is the stoichiometric coefficient in the sorbent and effluent chemical reaction and [effluent] baseline is the concentration of effluent in the dry emission gases in the absence of a sorbent.

For this and all subsequent examples the contact time between the effluent gas SO 2 in the off-gases and the solid sorbent particles, within the temperature T 2 was approximately one second.

Thus, the process of the present invention is effective in reducing SO 2 levels in the offgases of a combustion stream when an aqueous solution of an effluent sorbent is injected into the off-gas stream downstream of the combustion zone.

EXAMPLE III

In order to demonstrate the effect of temperature on the performance of the effluent sorbent when used in the process of the present invention, two additional tests were made under the same conditions set forth above with regard to Example II with the exception that in Test 1 the aqueous solution of calcium formate was injected into the off-gas stream when the off-gases were at a temperature of 2800 F and in Test 2 the aqueous solution of calcium formate was injected into the off-gas stream when the off-gases were at a temperature _ 1 90-181 of 19000 F. The concentration of SO 2 in the flue gas after injection of the effluent sorbent was measured and in the case of Test 1 the concentration was found to be 1890 ppm and in the case of Test 2 the concentration was found to be 2106 ppm. Thus, the level of SO 2 concentration in Test 1 corresponds to a 30% reduction in SO 2 emissions when compared to Example I and a' sorbent utilization of 30%. In Test 2 the concentration of SO 2 represents a 22% reduction in SO 2 emissions when compared to Example I and a 22% sorbent utilization. By comparing these results with that obtained in Example II it is seen that for optimum performance of the process of the present invention when injecting a sorbent solution into the off-gas stream, the temperature of the off-gases should be preferably between 2000' and 2300' F.

EXAMPLE IV

In order to demonstrate the effectiveness of a preferred embodiment of the present invention two additional tests were run under the same conditions set forth above with regard to Example III with the exception that iron gluconate was dissolved in the aqueous solution prior to injection into the off-gas stream. The iron to calcium molar ratio in the solution -1b 01- 90-181 was approximately 0.05. The calcium to sulfur molar ratio was maintained at 1.0. In Test 1 the aforesaid solution was injected into the flue gas stream when the flue gas stream was at a temperature of 22000 F. In Test 2 the injection took place when the flue gas stream was at a temperature of 28000 F. After injection the level of SO 2 in the flue gas was measured and in Test 1 was found to be 1450 ppm which corresponds to a 46% reduction in S02 emissions and a 46% sorbent utilization. In Test 2 the S02 level was found to be 1350 ppm which represents a 50% reduction in SO 2 when compared to Example I and a 50% sorbent utilization. The results of this example show that when a promoter is added to the aqueous solution of effluent sorbent the levels of So 2 reduction are increased and the temperature range T 2 at which the injection may take place is widened on the high temperature side.

EXAMPLE V

In order to demonstrate the effectiveness of a further embodiment of the process of the present invention, i.e. promoted calcium carbonate slurries, a further test was run employing an oil in water emulsion prepared from a heavy hydrocarbon crude having an 80 API gravity and a sulfur content of 3.87 wt.%. The heating _)l,- 90-181 value of the heavy crude was 17,500 BTU/lb. The oil in water emulsion was made by mixing 70 wt.% crude oil and 30 wt.% water with a surfactant. The resulting oil in water emulsion was combusted by injecting it into a furnace through a commercially available nozzle which employs air as an atomizing fluid. The oil in water emulsion was combusted to completion with air at a, firing rate of 56,000 BTU/hr and 3% oxygen in the flue gas. The resulting flue gases containing 2700 ppm S02 were carried off and cooled to a temperature of 2050 F. At this point a 5 wt.% slurry of calcium carbonate in water was injected into the off-gases. The particle size of the calcium carbonate was 0.07 microns as mean particle diameter. The amount of calcium injected was in a molar ratio to sulfur in the combustible fuel of 1. The S02 concentration of the dry flue gas was measured and found to be 2106 ppm which represents a 22% reduction in So 2 content and a 22% calcium utilization.

EXAMPLE V1

A further experiment was conducted under the same conditions of Example V above with the exception that iron gluConate was added to the calcium carbonate slurry in a proportion so as to provide an iron to calcium molar ratio of 0.05. The molar ratio of calcium to - V>0 - 90181 sulfur was 0.8. The slurry was injected into the off-gases at a temperature of 20500 F. The So 2 concentration of the flue gases was measured and found to be 1706 ppm which corresponds to a calcium utilization of 46%. This represents an increase of 109% over those results demonstrated in Example V above where the iron promoter was not employed.

EXAMPLE VII

In order to again demonstrate the effect of flue gas temperature on the effectiveness of the process of the present invention two tests were carried out, one with and one without iron additions. The first test was identical to Example V with the exception that injection took place at a flue gas temperature of 2300' F. The so 1) concentration was then measured and a reduction of so 2 of 30% was observed with the SO 2 level being 1890 ppm. This corresponds to a 30% calcium utilization. This represents a 36% increase as compared to Example V which employed an injection temperature of 20500 F. Test 2 was identical to Test 1 with the exception that iron glutonate was added to the slurry in a proportion so as to produce an iron to calcium molar ratio of 0.025. Again, slurry injection took place at a flue gas temperature of 23000 F. The SO 2 content of - 1 ( -- 90-181 the flue gas was measured at 1350 ppm and the calcium utilization was found to be 50%. Again, these results demonstrate that a small addition of a water soluble metal promoter into the slurry has a great benefit on emissions reductions in the process of the present invention.

EXAMPLE VIII

In order to demonstrate the effectiveness of a further embodiment of the process of the present invention, a slurry of hydrated lime [Ca(OH) 2 3 in water was used thistime. The furnace firing conditions and fuel were the same as in Example V. The hydrated lime slurry was prepared by hydrating calcium oxide (Cao). The Cao used to prepare the slurry had a particle size ranging between around 1 and 20 microns. The calcium to sulfur molar ratio was about 1.0. The temperature of the off-gases at the point of injection was 2050OF (1121'C). Two runs were carried out, the first run without promoter, the second with iron gluconate (Fe/Ca = 0,025 molar) dissolved into the hydration water. The SO 2 concentration of the off-gases after injection of the non-promoted calcium hydroxide slurry was 2241 ppm. For the second run promoted calcium nydroxide was injected into the a <20 90-181 off-gases held at the same temperature as before (2050OF). The SO 2 concentration after injection was 1809 ppm which results in a reduction of 34% of the total SO 2 emission, and a 94%.increase with respect to the case where no promoter is present. These results indicate again that the addition of the promoter according to the methods used in this invention substantially increases SO 2 capture from the flue gases.

EXAMPLE IX

The effectiveness of a further embodiment of the process of the present invention consisting in the use of dry promoted calcium hydroxide injection as an effective SO 2 sorbent, is demonstrated in this example.

The furnace firing conditions and fuel are similar as in Example V, therefore similar SO 2 emissions (2700 ppm) were observed when no sorbent was injected into the off-gases.

The starting material for the calcium hydroxide preparation was calcium oxide. Addition of water in amounts of 50-60 percent of the CaO mass produces a dry calcium hydroxide ready to be injected into the flue gas. Dissolution of an iron salt like iron gluconate into the hydration water allows to produce a dry 90-181 promoted calcium hydroxide ready to be injected into the flue gases. Both materials promoted and non-promoted calcium oxide were used in separated runs. In the first run dry non-promoted calcium hydroxide was injected into the flue gas stream at 2000OF (10930C). A calcium to sulfur molar ratio of one was used. After injection of the dry sorbent the So 2 concentration was 1566 ppm, Another run was carried injecting promoted calcium hydroxide in which the iron to calcium molar ratio was of 0.05. After injection of the dry sorbent into the off-gases at the point where the gas temperature was 2000F, the SO 2 concentration was 1566 ppm, this is a 121% increase in So 2 capture with respect to the case where the dry sorbent is not promoted.

This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein.

- _1 90-181

Claims

WHAT IS CLAIMED IS

1. A process for removing effluents from off-gases generated by the combustion of a fuel comprising: combusting said fuel in a combustion zone at a temperature T 1 so as to generate off-gases containing effluents; transporting said off-gases from said combustion zone and cooling said off-gases to a temperature of T 2 where T 2 is less than T1; providing an effluent sorbent; and injecting said effluent sorbent into said off-gases downstream of said combustion zone at a point where the temperature of said off-gases is T 2 such that said sorbent absorbs said effluents from said off-gases.

2. A process according to claim 1 including mixing said effluent sorbent with water so as to form an aqueous effluent sorbent mixture prior to injecting.

3. A process according to claim 2 including injecting said effluent sorbent mixture into said off-gases so as to produce a fine spray having an average droplet size of less than 100 microns.

90-181

4. A process according to claim 2 including injecting said effluent sorbent mixture into said off-gases so as to produce a fine spray having an average droplet size of less than 50 microns.

5. A process according to claim 3 including forming said effluent sorbent mixture by admixing a water soluble sorbent compound selected from the group consisting of calcium compounds, magnesium compounds and mixtures thereof.

6. A process according to claim 3 including forming said effluent sorbent mixture by admixing a water insoluble compound selected from the group consisting of calcium compounds, magnesium compounds and mixtures thereof.

7. A process according to claim 5 further including admixing a water soluble metal salt promoter with said effluent sorbent mixture wherein said promoter is selected from the group consisting of salts of iron, copper, manganese, boron, aluminum, sodium, potassium, zinc, nickel and mixtures thereof.

- t-,- 90-181

8. A process according to claim 6 further including admixing a water soluble metal salt promoter with said effluent sorbent mixture wherein said promoter is selected from the group consisting of salts of iron, copper, manganese, boron, aluminum, sodium, potassium, zinc, nickel and mixtures thereof.

9. A process according to claim 5 wherein said promoter is selected from the group consisting of salts of iron, copper, manganese, boron and mixtures thereof.

10. A process according to claim 6 wherein said promoter is selected from the group consisting of salts of iron, copper, manganese, boron and mixtures thereof.

11. A process according to claim 5 wherein said promoter is selected from the group consisting of salts of iron, copper and mixtures thereof.

12. A process according to claim 6 wherein said promoter is selected from the group consisting of salts of iron, copper and mixtures thereof.

13. A process according to claim 7 wherein the molar ratio of water soluble sorbent to effluent is between 0.4 to 1.2.

2,-- 90-181

14. A process according to claim 7 wherein the molar ratio of water soluble sorbent to effluent is between 0.6 to 1.0.

15. A process according to claim 8 wherein the molar ratio of water insoluble sorbent to effluent is between 0.5 to 2.5.

16. A process according to claim 8 wherein the molar ratio of water insoluble sorbent to effluent is between 0.8 to 2.0.

17. A process according to claim 13 wherein the molar ratio of promoter to sorbent is between 0.01 to 0.15.

18. A process according to claim 14 wherein the molar ratio of promoter to sorbent is between 0.01 to 0.05.

19. A process according to claim 15 wherein the molar ratio of prornoter to sorbent is between 0.01 to 0.10.

_; b --I 90-181

20. A process according to claim 16 wherein the molar ratio of promoter to sorbent is between 0.01 to 0.10.

21. A process according to claim 13 wherein T 2 is between 200CP and 2300'F.

22. A process according to claim 15 wherein T is between 1800OF and 2200F.

2

23. A process according to claim 7 wherein T2 is between 1650OF and 2800F.

24. A process according to claim 1 including the steps of forming an oil in water emulsion as the fuel.

25. A process according to claim 1 including atomizing said fuel prior to combustion.

26. A process according to claim 1 wherein the fuel is a liquid fuel.

27. A process according to claim 1 wherein the fuel is a solid fuel.

---P1,_7 - 90-181

28. A process according to claim 6 including spiking said effluent sorbent with a water soluble promoter selected from the group consisting of salts of iron, copper, manganese, boron, aluminum, sodium, potassium, zinc, nickel and mixtures thereof.

29. A process according to claim 28 including forming said spiked effluents sorbent particles into particles having an average particle size of less than 50 microns.

30. A process according to claim 28 including forming said spiked effluents sorbent particles into particles having an average particle size of less than 10 microns.

31. The in-situ removal of effluents from a gaseous stream by injection of an effluent sorbent into downstream of the combustion zone substantially as herein described.