Inflame desulfurization and denoxification of high sulfur containing fuels

Abstract

A process for the preparation of a liquid fuel and resulting fuel including a sulfur and nitrogen capturing additive consisting essentially of Na.sup.+, Fe.sup.++ and an element X selected from group consisting of Mg.sup.++, Ba.sup.++, Ca.sup.++, Li.sup.+, K.sup.+ and mixtures thereof wherein Na.sup.+ is present in an amount of less or equal to 40 wt. % based on the total weight of the water soluble additive Fe.sup.++ is present in an amount of greater than or equal to 0.4 wt. % based on the total weight of the water soluble additive with the balance essentially element X wherein the ratio of Na.sup.+ and Fe.sup.++ is about between 7.5:1.0 to 100:1.0.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a process for the preparation of liquid fuels and the resulting fuel and, more particularly, a process that allows a high sulfur and nitrogen containing fuel to be converted into energy by combustion with a substantial reduction in sulfur oxide emissions and nitrogen oxide emissions.

Low gravity, viscous hydrocarbons found in Canada, The Soviet Union, United States, China and Venezuela are normally liquid with viscosities ranging from 10,000 to 200,000 CP and API gravities of less than 12. These hydrocarbons are currently produced either by mechanical pumping, steam injection or by mining techniques. Wide-spread use of these materials as fuels is precluded for a number of reasons which include difficulty in production, transportation and handling of the material and, more importantly, unfavorable combustion characteristics including high sulfur oxide emissions and unburned solids. To date, there are two commercial processes practiced by power plants to reduce sulfur oxide emissions. The first process is furnace limestone injection wherein limestone injected into the furnace reacts with the sulfur oxides to form solid sulfate particles which are removed from the flue gas by conventional particulate control devices. The cost for burning a typical high sulfur fuel by the limestone injection method is between two to three dollars per barrel and the amount of sulfur oxides removed by the methods is in the neighborhood of 50%. A more effective process for removing sulfur oxides from power plants comprises flue gas desulfurization wherein CaO+H.sub.2 O are mixed with the flue gases from the furnace. In this process 90% of the sulfur oxides are removed; however the cost for burning a barrel of fuel using the process is between four and five Dollars per barrel. Because of the foregoing, the high sulfur content, viscous hydrocarbons have not been successfully used on a commercial basis as fuels due to the high costs associated with their burning.

It is well known in the prior art to form oil in water emulsions for use as a combustible fuel. See for example U.S. Pat. Nos. 4,114,015; 4,378,230 and 4,618,348. In addition to the foregoing, the prior art teaches that oil in water emulsions formed from low gravity, viscous hydrocarbons can likewise be successfully combusted as a fuel. See for example British Patent Specification No. 974,042 and U.S. Pat. No. 4,618,348. The assignee of the instant application has discovered that sulfur-oxide emissions can be controlled when burning viscous high sulfur containing hydrocarbon in water emulsions by the addition of sulfur capturing additives to the emulsion composition. See U.S. Application Ser. Nos. 875,450 and 014,871.

Naturally, it would be highly desirable to develop a process for the preparation of liquid fuels and a resultant liquid fuel which, upon combustion, has a substantial reduction in sulfur oxide and nitrogen oxide emissions.

Accordingly, it is the principal object of the present invention to provide an additive for addition to a hydrocarbon fuel which, upon combustion of the fuel, acts as a sulfur and nitrogen capturing agent so as to substantially reduce the formation and emission of sulfur and nitrogen oxides.

It is a particular object of the present invention to provide a process as set forth above which is useful for hydrocarbon in water emulsions to be burned as fuels.

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

SUMMARY OF THE INVENTION

The present invention relates to a process for the preparation of liquid fuels and the resulting fuel and, more particularly, a process that allows a high sulfur and nitrogen containing fuel to be converted into energy by combustion with a substantial reduction in sulfur oxide emissions and nitrogen oxide emissions.

It is well known in the art to form oil in water emulsions either from naturally occurring bitumens or residual oil in order to facilitate the production and/or transportation of these viscous hydrocarbons. Typical processes are disclosed in U.S. Pat. Nos. 3,380,531; 3,467,195; 3,519,006; 3,943,954; 4,099,537; 4,108,193; 4,239,052 and 4,570,656. In addition to the foregoing, the prior art teaches that oil in water emulsions formed from naturally occurring bitumens and/or residual oils can be used as combustible fuels. See for example U.S. Pat. Nos. 4,144,015; 4,378,230 and 4,618,348.

The present invention is drawn to a process for the preparation of a liquid fuel and the resulting fuel which, upon combustion, exhibits a substantial reduction in sulfur oxide emissions and nitrogen oxide emissions. As noted above, the particular process is useful for fuels in the form of hydrocarbon in water emulsions as disclosed in co-pending Application Ser. Nos. 014,871 and 875,450.

The process of the present invention comprises admixing a sulfur and nitrogen containing hydrocarbon (either hydrocarbon residual, hydrocarbon in water emulsion, or other suitable hydrocarbon) with a water soluble additive which acts as a capturing agent for sulfur and nitrogen upon combustion of the hydrocarbon as a fuel. In accordance with the present invention, the water soluble additive consists essentially of Na.sup.+, Fe.sup.++ and an element X selected from group consisting of Mg.sup.++, Ba.sup.++, Ca.sup.++, Li.sup.+, K.sup.+ and mixtures thereof wherein Na.sup.+ is present in an amount of less than or equal to 40 wt.% based on the total weight of the water soluble additive, Fe.sup.++ is present in an amount of greater than or equal to 0.4 wt.% based on the total weight of the water soluble additive with the balance essentially element X wherein the ratio of Na.sup.+ and Fe.sup.++ is about between 7.5:1.0 to 100:1.0.

It has been found that the Fe.sup.++ addition acts as a nitrogen capturing agent thereby reducing the amount of nitrogen oxide emissions. The Na.sup.+ addition acts as a strong sulfur capturing agent for reducing sulfur oxide emissions; however, as the Na.sup.+ addition tends to be corrosive to boiler apparatuss the amount of Na.sup.+ in the additive should be limited. The remaining element X acts as a sulfur capturing agent and is used as a positive addition to complement the amount of Na.sup.+ in the additive formulation. The overall additive formulation results in an effective sulfur and nitrogen capturing additive which does not result in serious detrimental corrosion of boiler apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bar graph showing the effect of additives on the reduction of SO.sub.2 emissions.

FIG. 2 is a bar graph showing the effect of additives on the reduction of nitrogen oxide emissions.

DETAILED DESCRIPTION

In accordance with the present invention, the process of the present invention is drawn to the preparation and burning of a fuel formed from a naturally occurring bitumen or residual fuel oil product. One of the fuels for which the process is suitable is a bitumen crude oil having a high sulfur content such as those crudes typically found in the Orinoco Belt of Venezuela. The bitumen or residual oil has the following chemical and physical properties: C wt.% of 78.2 to 85.5, H wt.% of 9.0 to 10.8, O wt.% of 0.2 to 1.3, N wt.% of 0.50 to 0.70, S wt.% of 2 to 4.5, Ash wt.% of 0.05 to 0.33, Vanadium, ppm of 50 to 1000, Nickel, ppm of 20 to 500, Iron, ppm of 5 to 60, Sodium, ppm of 30 to 200, Gravity, .degree.API of 1.0 to 12.0, Viscosity (CST), 122.degree. F. of 1,000 to 5,100,000, Viscosity (CST), 210.degree. F. of 40 to 16,000, LHV (BTU/lb) of 15,000 to 19,000, and Asphaltenes wt.% of 9.0 to 15.0. In accordance with one feature of the present invention, a mixture comprising water and an emulsifying additive is mixed with a viscous hydrocarbon or residual fuel oil so as to from an oil in water emulsion. The characteristics of the oil in water emulsion and the formation of same are set forth in the above-referenced co-pending applications which are incorporated herein by reference. In accordance with the present invention, an additive which captures sulfur and nitrogen and prohibits the formation and the emission of sulfur oxides and nitrogen oxides during combustion of the hydrocarbon or hydrocarbon in water emulsion fuel is added to the fuel prior to the combustion of same. The water soluble additive for use in the process of the present invention consists essentially of Na.sup.+, Fe.sup.++ and an element X selected from the group consisting of Mg.sup.++, Ba.sup.++, Ca.sup.++, Li.sup.+, K.sup.+ and mixtures thereof. In accordance with the particular feature of the present invention the Na.sup.+ is present in an amount of less than or equal to 40 wt.% based on the total weight of the water soluble additive. The Fe.sup.++ is present in an amount of greater than or equal to 0.4 wt.% based on the total weight of the water soluble additive. The balance of the water soluble additive is made up by the element X. The ratio of Na.sup.+ to Fe.sup.++ in the additive ranges from about between 7.5:1.0 to 100:1.0. The preferred formulation for the additive of the present invention used in the process of the present invention consists essentially of Na.sup.+ in an amount of between 5 to 40 wt.% based on the total weight of the water soluble additive, Fe.sup.++ in an amount of 0.4 to 2.0 wt.% based on the total weight of the water soluble additive with the balance essentially element X. It has been found that in order to obtain the desired emissions levels with respect to sulfur and nitrogen upon combustion of the fuel produced by the process of the present invention, the additive must be present in a molar ratio of additive to sulfur in the fuel of greater than or equal to 0.500 and preferably greater than 0.750.

The advantages of the present invention will be clear from consideration of the following example.

EXAMPLE

In order to demonstate the effect of the additive of the present invention on the combustion characteristics of hydrocarbon fuels containing sulfur and nitrogen, ten additive formulations were prepared. The composition of the additive formulations are set forth hereinbelow in Table I.

TABLE I______________________________________Additive Composition (wt. %)No. Mg Na Fe______________________________________1 80.5 18.9 0.652 62.2 37.3 0.503 67.4 32.1 0.404 67.4 32.1 0.435 79.5 19.2 1.286 61.9 37.1 0.997 83.0 15.9 1.068 67.2 32.0 0.869 2.7 97.3 0.0010 98.8 0.00 1.2______________________________________

Each of the additives were added to various oil in water emulsions for burning as natural fuels. The fuel characteristics operating conditions and combustion characteristics for the fuels admixed with each additive are set forth below in Tables II-XI.

TABLE II__________________________________________________________________________ADDITIVE NO. 1 BASELINE EMULSION EMULSION EMULSION EMULSION EMULSION EMULSION #1 #2 #3 #4 #5__________________________________________________________________________FUEL CHARACTERISTICSAdditive 1/S 0 0.25 0.38 0.50 0.75 0.91(Molar Ratio)LHV (BTU/lb) 12995 12029 11608 11203 10484 9852Bitumen, wt. % 74 68.5 66.1 63.8 59.7 56.1Water, wt. % 26 31.5 33.9 36.2 40.3 43.9Sulfur, wt. % 2.8 2.6 2.5 2.4 2.3 2.1OPERATING CONDITIONSFeed Rate (lb/h) 55.1 59.5 61.7 63.9 68.3 72.7Thermal Input 0.75 0.75 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151 149 150(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 16 10 4 15 11CO.sub.2 (Vol %) 14.3 14.5 14.5 15.0 15.0 14.0O.sub.2 (Vol %) 3.0 3.0 2.9 2.8 2.9 2.9SO.sub.2 (ppm) 2100 1175 1000 700 350 200SO.sub.2 Reduction (%) 0 44.1 52.4 66.7 83.3 90.5NO.sub.x (ppm) 550 435 300 240 140 150NO.sub.x reduction (%) 0 20.9 45.5 56.4 74.6 72.7Combustion 99.8 99.9 99.9 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ TABLE III__________________________________________________________________________ADDITIVE NO. 2 BASELINE EMULSION EMULSION EMULSION EMULSION EMULSION #1 #2 #3 #4__________________________________________________________________________FUEL CHARACTERISTICSAdditive 2/S 0 0.33 0.49 0.65 0.70(Molar Ratio)LHV (BTU/lb) 12995 12029 11608 11203 10484Bitumen, wt. % 74 68.5 66.1 63.8 59.7Water, wt. % 26 31.5 33.9 36.2 40.3Sulfur, wt. % 2.8 2.6 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 59.5 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151 149(.degree.F.)Steam Fuel Ratio 0.30 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 5 5 14 7CO.sub.2 (Vol %) 14.3 14.0 14.0 14.0 14.0O.sub.2 (Vol %) 3.0 3.0 2.9 3.0 3.2SO.sub.2 (ppm) 2100 1150 750 380 280SO.sub.2 Reduction (%) 0 45.2 64.3 81.2 86.7NO.sub.x (ppm) 550 260 210 180 120NO.sub.x reduction (%) 0 52.7 62.0 67.3 78.2Combustion 99.8 99.9 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ (*) Analyzer out of service TABLE IV__________________________________________________________________________ADDITIVE NO. 3 BASELINE EMULSION EMULSION EMULSION EMULSION EMULSION #1 #2 #3 #4__________________________________________________________________________FUEL CHARACTERISTICSAdditive 3/S 0 0.30 0.45 0.60 0.90(Molar Ratio)LHV (BTU/lb) 12995 12029 11608 11203 10484Bitumen, wt. % 74 68.5 66.1 63.8 59.7Water, wt. % 26 31.5 33.9 36.2 40.3Sulfur, wt. % 2.8 2.6 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 59.5 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151 149(.degree.F.)Steam Fuel Ratio 0.30 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 16 26 6 5CO.sub.2 (Vol %) 14.3 14.0 14.5 14.0 14.0O.sub.2 (Vol %) 3.0 3.1 2.7 3.0 2.9SO.sub.2 (ppm) 2100 1250 900 600 250SO.sub.2 Reduction (%) 0 40.5 57.0 71.4 88.1NO.sub.x (ppm) 550 310 210 115 (*)NO.sub.x reduction (%) 0 44.0 62.0 79.1 (*)Combustion 99.8 99.9 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ (*) Analyzer out of service. TABLE V__________________________________________________________________________ADDITIVE NO. 4 BASELINE EMULSION EMULSION EMULSION EMULSION #1 #2 #3__________________________________________________________________________FUEL CHARACTERISTICSAdditive 4/S 0 0.38 0.56 0.75(Molar Ratio)LHV (BTU/lb) 12995 12029 11608 11203Bitumen, wt. % 74 68.5 66.1 63.8Water, wt. % 26 31.5 33.9 36.2Sulfur, wt. % 2.8 2.6 2.5 2.4OPERATING CONDITIONSFeed Rate (lb/h) 55.1 59.5 61.7 63.9Thermal Input 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 14 14 13CO.sub.2 (Vol %) 14.3 14.0 14.0 10.0O.sub.2 (Vol %) 3.0 2.9 2.8 3.1SO.sub.2 (ppm) 2100 1100 650 200SO.sub.2 Reduction (%) 0 48.0 69.1 90.5NO.sub.x (ppm) 550 280 240 140NO.sub.x reduction (%) 0 49.0 56.4 74.6Combustion 99.8 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ (*) Analyzer out of service. TABLE VI__________________________________________________________________________ADDITIVE NO. 5 BASELINE EMULSION EMULSION EMULSION EMULSION EMULSION #1 #2 #3 #4__________________________________________________________________________FUEL CHARACTERISTICSAdditive 5/S 0 0.15 0.38 0.50 0.75(Molar Ratio)LHV (BTU/lb) 12995 12029 11608 11203 10484Bitumen, wt. % 74 68.5 66.1 63.8 59.7Water, wt. % 26 31.5 33.9 36.2 40.3Sulfur, wt. % 2.8 2.6 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 59.5 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151 149(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCo (ppm) 10 3 3 4 6CO.sub.2 (Vol %) 14.3 14.0 14.0 14.5 14.5O.sub.2 (Vol %) 3.0 3.0 3.0 3.0 3.0SO.sub.2 (ppm) 2100 1100 725 680 350SO.sub.2 Reduction (%) 0 47.6 65.5 67.6 83.3NO.sub.x (ppm) 550 350 350 200 (*)NO.sub.x reduction (%) 0 36.4 36.4 63.6 (*)Combustion 99.8 99.9 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ (*) Analyzer out of service. TABLE VII__________________________________________________________________________ADDITIVE NO. 6 BASELINE EMULSION EMULSION EMULSION EMULSION #1 #2 #3__________________________________________________________________________FUEL CHARACTERISTICSAdditive 6/S 0 0.49 0.65 0.70(Molar Ratio)LHV (BTU/lb) 12995 11608 11203 10484Bitumen, wt. % 74 66.1 63.8 59.7Water, wt. % 26 33.9 36.2 40.3Sulfur, wt. % 2.8 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 4 10 15CO.sub.2 (Vol %) 14.3 15.0 15.0 15.0O.sub.2 (Vol %) 3.0 2.7 3.0 3.0SO.sub.2 (ppm) 2100 650 350 250SO.sub.2 Reduction (%) 0 69.0 83.3 88.1NO.sub.x (ppm) 550 320 140 140NO.sub.x reduction (%) 0 41.8 74.5 74.5Combustion 99.8 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ TABLE VIII__________________________________________________________________________ADDITIVE NO. 7 BASELINE EMULSION EMULSION EMULSION EMULSION #1 #2 #3__________________________________________________________________________FUEL CHARACTERISTICSAdditive 7/S 0 0.45 0.60 0.90(Molar Ratio)LHV (BTU/lb) 12995 11608 11203 10484Bitumen, wt. % 74 66.1 63.8 59.7Water, wt. % 26 33.9 36.2 40.3Sulfur, wt. % 2.8 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 10 6 8CO.sub.2 (Vol %) 14.3 15.0 15.0 14.5O.sub.2 (Vol %) 3.0 3.0 2.9 2.8SO.sub.2 (ppm) 2100 800 550 200SO.sub.2 Reduction (%) 0 61.9 73.8 90.5NO.sub.x (ppm) 550 260 150 62NO.sub.x reduction (%) 0 52.7 72.7 88.7Combustion 99.8 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ TABLE IX__________________________________________________________________________ADDITIVE NO. 8 BASELINE EMULSION EMULSION EMULSION EMULSION #1 #2 #3__________________________________________________________________________FUEL CHARACTERISTICSAdditive 8/S 0 0.56 0.75 0.93(Molar Ratio)LHV (BTU/lb) 12995 11608 11203 10484Bitumen, wt. % 74 66.1 63.8 59.7Water, wt. % 26 33.9 36.2 40.3Sulfur, wt. % 2.8 2.5 2.4 2.3OPERATING CONDITIONSFeed Rate (lb/h) 55.1 61.7 63.9 68.3Thermal Input 0.75 0.75 0.75 0.75(MMBTU/h)Fuel Temperature 149 150 149 151(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 10 30 7 10CO.sub.2 (Vol %) 14.3 14.0 14.0 14.0O.sub.2 (Vol %) 3.0 3.0 2.9 3.0SO.sub.2 (ppm) 2100 550 180 75SO.sub.2 Reduction (%) 0 73.8 91.4 96.4NO.sub.x (ppm) 550 230 150 100NO.sub.x reduction (%) 0 58.2 67.3 81.8Combustion 99.8 99.9 99.9 99.9Efficiency (%)__________________________________________________________________________ TABLE X______________________________________ADDITIVE NO. 9 BASELINE EMULSION EMULSION EMULSION #1 #2______________________________________FUEL CHARACTERISTICSAdditive 9/S 0 0.011 0.097(Molar Ratio)LHV (BTU/lb) 13337 13277 12900Bitumn, wt. % 78 78 70Water, wt. % 22 22 30Sulfur, wt. % 3.0 3.0 2.7OPERATING CONDITIONSFeed Rate (lb/h) 60.0 60.0 66.7Thermal Input 0.82 0.82 0.82(MMBTU/h)Fuel Temperature 154 154 154(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO (ppm) 36 27 20CO.sub.2 (Vol %) 13.0 12.9 12.9O.sub.2 (Vol %) 3.0 2.9 3.0SO.sub.2 (ppm) 2347 1775 165SO.sub.2 Reduction (%) 0 24.4 93.1NO.sub.x (ppm) 450 498 434NO.sub.x reduction (%) 0 (9.7) 3.5Combustion 99.8 99.8 99.9Efficiency (%)______________________________________ TABLE XI______________________________________ADDITIVE NO. 10 BASELINE EMULSION EMULSION EMULSION #1 #2______________________________________FUEL CHARACTERISTICSAdditive 10/S 0 0.30 0.78(Molar Ratio)LHV (BTU/lb) 13086 12742 10845Bitumen, wt. % 76 74 63Water, wt. % 24 26 37Sulfur, wt. % 2.9 2.8 2.4OPERATING CONDITIONSFeed Rate (lb/h) 55.1 56.2 66.0Thermal Input 0.72 0.72 0.72(MMBTU/h)Fuel Temperature 149 149 149(.degree.F.)Steam/Fuel Ratio 0.30 0.30 0.30(w/w)Steam Pressure 2.4 2.4 2.4(bar)COMBUSTION CHARACTERISTICSCO.sub.2 (Vol %) 13.5 14.0 13.2O.sub.2 (Vol %) 3.0 2.9 3.0SO.sub.2 (ppm) 2357 1250 167SO.sub.2 Reduction (%) 0 47.0 92.9NO.sub.x (ppm) 500 430 218NO.sub.x reduction (%) 0 14.0 56.4Combustion 99.8 99.9 99.8Efficiency (%)______________________________________

As can be seen from the foregoing tables, Fe.sup.++ additions to the additive has a marked effect on reducing nitrogen oxide emissions upon combustion of the fuel. The comparative effect of Fe.sup.++ on nitrogen oxide additions compared to the effect obtained from Na.sup.+ and element X (in this case magnesium) is set forth in FIG. 2. Likewise, as can be seen from the foregoing tables II-XI, Na.sup.+ has a marked effect on reducing sulfur oxide emissions when compared to iorn and the element X addition. See FIG. 1.

In addition to the foregoing, it is seen from the foregoing combustion data that the molar ratio of additive to sulfur in the hydrocarbon fuel has an effect on the reduction of SO.sub.2 and nitrogen oxide with reductions of greater than 80% in SO.sub.2 being obtained at molar ratios of additive to sulfur of greater than 0.500 and preferably greater than 0.750.

In addition to the foregoing, the combustion ash characterisitics for Emulsion 5 of Table II and Emulsion 2 of Table IX were analyzed. The compositions are set forth below in Table XII.

TABLE XII______________________________________ASH CHARACTERISTICS Melting PointAdditive Compound (.degree.F.) Observations______________________________________TABLE X 3Na.sub.2 O.V.sub.2 O.sub.5 1562 POTENTIALLYADDITIVE 2Na.sub.2 O.V.sub.2 O.sub.5 1184 CORROSIVE9 Na.sub.2 O.V.sub.2 O.sub.5 1166 Na.sub.2 SO.sub.4 1616 Na.sub.2 O.V.sub.2 O.sub.4.5V.sub.2 O.sub.5 1157TABLE II MgSO.sub.4 2055 NON-ADDITIVE 3MgO.V.sub.2 O.sub.5 2174 CORROSIVE1 NiSO.sub.4 1544 MgO 2642 Na.sub.2 SO.sub.4 1616______________________________________

The ash composition employing additive 9 (a high sodium additive composition) indicates that the ash is potentially corrosive and therefore undesirable. Accordingly, the ideal additive composition in order to minimize sulfur oxide and nitrogen oxide emissions and reduce the potential for corrosion comprises Na.sup.+ in an amount of about 5 to 40 wt.%, Fe.sup.++ in an amount of between 0.4 to 2.0 wt.% with the balance essentially element X.

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.

Claims

1. A process for controlling sulfur oxide and nitrogen oxide formation and emissions when burning by forming a combustible fuel prepared from a bitumen or residual fuel oil hydrocarbon containing sulfur and nitrogen comprising:

(a) mixing a sulfur and nitrogen containing hydrocarbon with a water soluble additive wherein said water soluble additive consist essentially of Na.sup.+, Fe.sup.++ and an element X selected from the group consisting of Mg.sup.++, Ba.sup.++, Ca.sup.++, Li.sup.+, K.sup.+ and mixtures thereof wherein Na.sup.+ is present in an amount of less than or equal to 40 wt.%, Fe.sup.++ is present in an amount of greater than or equal to 0.4 wt.%, balance essentially X wherein the ratio of Na.sup.+ to Fe.sup.++ is about between 7.5:1.0 to 100:1.0 and the molar ratio of additive to sulfur in said hydrocarbon is greater than about 0.500.

2. A process according to claim 1 wherein Na.sup.+ is present in an amount of between 15 to 40 wt.%, Fe.sup.++ is present in an amount of 0.4 to 2.0 wt.%, balance essentially X.

3. A process according to claim 1 wherein the molar ratio of additive to sulfur is greater than 0.750.

4. A process according to claim 1 wherein said hydrocarbon is a hydrocarbon in water emulsion formed by admixing a mixture of a sulfur containing hydrocarbon in water with an emulsifier wherein said emulsion has a water content of about between 5 to 40 volume percent.

5. A bitumen or residual fuel oil hydrocarbon combustible fuel comprising a sulfur and nitrogen containing hydrocarbon and a water soluble sulfur and nitrogen capturing additive wherein said water soluble additive consists essentially of Na.sup.+, Fe.sup.++ and an element X selected from the group consisting of Mg.sup.++, Ba.sup.++, Ca.sup.++, Li.sup.+, K.sup.+ and mixtures thereof wherein Na.sup.+ is present in an amount of less than or equal to 40 wt.%, Fe.sup.++ is present in an amount of greater than or equal to 0.4 wt.%, balance essentially X wherein the ratio of Na.sup.+ to Fe.sup.++ is about between 7.5:1.0 to 100:1.0 and the molar ratio of additive to sulfur is greater than 0.500.

6. A hydrocarbon combustible fuel according to claim 5 wherein Na.sup.+ is present in an amount of between 15 to 40 wt.%, Fe.sup.++ is present in an amount of 0.4 to 2.0 wt.%, balance essentially X.

7. A hydrocarbon combustible fuel according to claim 5 wherein the molar ratio of additive to sulfur is greater than 0.750.