US3734833A - Low sulphur fuel system - Google Patents

Abstract

IN ACCORDANCE WITH THE METHOD AND APPARATUS HEREIN SET FORTH, AN OIL FLUID COKER AND A COAL DEVOLATILIZER ARE INTERCONNECTED WITH A HEAT GENERATOR, WHEREBY TO EFFECT THE FORMATION OF A DARBONACEOUS PRODUCT OR CHAR, WHICH IS A COMBINATION OF OIL FLUID COKE AND DEVOLATILIZED COAL. BY-PRODUCTS FROM THE OIL FLUID COKER, AND FROM THE COAL DEVOLATILIZER, AND FROM THE HEAT GENERATOR MAY BE SEPARATELY WITHDRAWN. THE HEAT GENERATOR IS SECTIONALIZED TO PROVIDE FOR A MAXIMUM REMOVAL OF SULPHUR FROM THE CARBONACEOUS PRODUCT, OR FUEL, AND TO EFFECT A PARTIAL GASIFICATION THEREOF, AND TO PROVIDE FOR THE BURNING OR COMBUSTION OF THE FUEL DIRECTLY WITHIN THE HEAT GENERATOR, FOR MAXIMUM COMBUSTION EFFICIENCY.

Description

May 22 1973 A. D. SINGH LOW SULPHUR FUEL SYSTEM Filed Dec. l0,

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United States Patent O U.S. Cl. 201-17 14 Claims ABSTRACT F THE DISCLOSURE In accordance with the method and apparatus herein set forth, an oil fluid coker and a coal devolatilizer are interconnected with a heat generator, whereby to effect the formation of a carbonaceous product or char, which is a combination of oil fluid coke and devolatilized coal. By-products from the oil fluid coker, and from the coal devolatilizer, and from the heat generator may be separately withdrawn. The heat generator is sectionalized to provide for a maximum removal of sulphur from the carbonaceous product, or fuel, and to effect a partial gasification thereof, and to provide for the burning or combustion of the fuel directly within the heat generator, for maximum combustion efficiency.

This invention relates to a process and apparatus providing a low sulphur fuel system; and utilizes a process and apparatus of the general type and kind set forth in my prior Pat. No. 3,437,562, dated Apr. 8, 1969, and entitled Process for Producing Combined Coal Char and Oil Coke, and Co-Products Therewith. The present invention provides certain improvements over the process and appartus set forth in my prior patent.

One important improvement provided by the present invention is the provision of means and methods for burning the carbonaceous product formed by the combined fluid coking of oil and devolatilization of coal directly Within and as a part of the formation process; whereby the expense of heat loss of separately provided combustion apparatus is avoided.

A further object of the invention is to provide, in connection with the above, improved burning or combustion means for the carbonaceous product, or combined char,.

whereby to provide increased efficiency in the combustion or burning of the combined char fuel product.

A still further object of the invention is to provide in a process for producing coal char and oil fluid coke, improved means for effecting a reduction of sulphur in the products of combustion, by the use of a reducing agent, such for example as hydrogen, embodied as a part of the fuel production system. p

A still further object of the invention is to provide in a process and apparatus of the type set forth, means for effecting a gasification of the fuel, in a desired degree, whereby to gasify a desired proportion of the end products of the system, and thereby effect a gasification of the originally supplied fuel, as for example the coal.

Various other objects, advantages and features of the invention will be apparant from the following description, taken in connection with the accompanying draw- ICC ing, wherein a preferred embodiment of the invention is set forth for purposes of illustration.

Referring more specifically to the drawing:

FIG. l sets forth a diagrammatic View of the disclosed embodiment, and

FIG. 2 is an enlargement of a portion thereof.

There is illustrated an oil fiuid coker 10, a coal devolatilizer 12, and a heat generator 14 of the general type and kind, and in the general arrangement set forth in my prior patent.

As in said prior patent, preheated oil under pressure, which may be crude oil, reduced crude oil, or other modified residual oil such for example as Bunker-C or the like, is supplied from a supply line 16 to a plurality of spray nozzles 18 and 20 within the oil fluid coker, under control of valves 22 and 24.

As shown, suitably granulated raw coal, together with steam, fuel gas, or other fluidizing media, is introduced into the coal devolatilizer, under pressure, from a supply line 26 under control of a valve 28.

The heat generator 14 is in certain aspects and functions similar to the heat generator of my said prior patent, but also differs materially therefrom. More specifically, in this instance the heat generator is provided with an upper chamber or section 30, an intermediate chamber or section 32, and a lower chamber or section 34. Product from the oil coker discharged from the lower end thereof through :a conduit 36 under control of a valve 38, is transmitted by preheated air under pressure from a supply line 40, under control of a valve 42, through a conduit 44 into the upper section 30 of the heat generator. In a similar manner product from the coal devolatilizer delivered from the lower end thereof through a conduit 46 under control of a valve 48, is delivered by preheated air under pressure from a supply line 50 under control of a va-lve 52, through a conduit 54 also into the upper chamber 30 of the heat generator.

As shown, product is delivered from the upper generator section or chamber 30 into the intermediate chamber or section 32 by means of a valve controlled conduit 56; and similarly product is delivered from the intermediate chamber or section 32 into the lower section or chamber of the heat generator, through a valve controlled conduit 58. Product is also transmitted from the upper heat generator section 30 into the oil fluid coker through a conduit 60 under control of a valve 62.

In a similar manner product from the upper chamber 30 of the heat generator is transmitted to the coal devolatilizer through a conduit 68 under control of a valve 70, and/ or through a conduit 72 under control of a valve 74; into the -supply conduit 26.

The operation of the parts thus far described is generally similar to the operation in my said prior Pat. No. 3,437,562. Within the oil fluid coker the oil -delivered thereto is subjected to a partial cracking and coking procc ss and the coal delivered to the coal devolatilizer is subjected to devolatilization, and heat treatment, and the products therefrom are delivered through the conduits 44 and 54 into the upper section 30 of the heat generator. Product from the upper section 30 of the heat generator is in turn transmitted back to the oil fluid coker through the conduit 60, and to the coal devolatilizer through the conduits 68 and/ or 72. A partial burning of the product, and thus a heat generation, is provided within the heat generator section 30, thus supplying heat to the system, within the heat generator and within the oil Huid coker and the coal devolatilizer. Through the continuous interchange of material, as above set forth, a carbonaceous product is formed which is a combination of oil fluid coke and coal char, all as set forth with particularity in my said prior patent.

To effect a proper functioning of the system, steam is supplied as a stripping medium from a supply conduit 76 to stripping heads disposed respectively within the conduits 60 and 36, the delivery of the steam to the stripping heads being suitably individually valve controlled. Steam is also supplied from conduit 76 to a iluidizing head 78 within the lower portion of the oil fluid coker, under control of a 'valve 80. In a similar manner steam is supplied as a stripping medium from a supply conduit 82 to valve controlled stripping heads individually disposed within the conduits 68, 72 and 46; and steam from the supply line 82 is also supplied to a fluidizing head 84 within the lower portion of a coal devolatilizer, under control of a valve 86.

As has been previously described, in accordance with the present invention the heat generator is sectionalized into an upper section or chamber 30, and an intermediate section or chamber 32. Preheated air under pressure is supplied through a valve controlled conduit 88 into the upper heat generator section, to a fluidizing head 90, which acts to fluidize the bed, and also supplies air to the chamber so as to effect a partial burning of the product within the chamber, as previously described. Pressure is maintained within the chamber 30, within the range from 50 p.s.i. to 1000 p.s.i., and preferably approximating the latter, for reasons as will be presently described. This of course requires that the entire system be operated under pressure, to permit an interchange of the materials between the vessels. The temperature within chamber is preferably maintained at approximately l250 F., and temperatures within the oil fluid coker and the coal devolatilizer may be maintained within the range of l900 F. to 1000 F.

By-products from the' oil uid coker may be collected through a discharge conduit 92 under control of a valve 94; and from the coal devolatilizer through a conduit 96 under control of a valve 98; and from the upper section of the heat generator through a conduit 100 under control of a valve 102, the by-products thus delivered, and to be recovered, being es sentially similar to those discharged from the oil fluid coker, the coal devolatilizer, and the heat generator in the apparatus and process of my said prior patent.

In accordance with the present invention the product within the intermediate heat generator chamber 32 is subjected to the action of hydrogen gas, supplied thereto from a supply line 104 under control of a valve 106, leading to a iluidizing head 108 within the lower portion of the said intermediate chamber 32. Preferably the temperature of the product within the chamber 32 is maintained in the range of 1600 F. to 1800 F.

Within this high temperature range hydrogen reacts very readily with the sulphur in the combined char, the resulting gases consisting essentially of H2S, excess H2, and some hydrocarbon gases being discharged from the intermediate chamber through an exhaust line or conduit 109 under control of a valve 110.

Further, in accordance with the present invention, the exhaust products from the line or conduit 109 are subjected to the action of a lime or dolomite hydrogen recovery system, generally indicated by the reference numeral 112, from which, after treatment, at least a considerable portion of the hydrogen is recovered for recirculation to the heat generator section 32.

More particularly, the hydrogen recovery apparatus may comprise an upper chamber 114, within which the lime or dolomite is disposed, and to which the exhaust gases consisting essentially of H2S and H2 may be delivered from the chamber 32, as previously set forth. The solid reaction products from chamber 114 of the hydrogen recovery apparatus are delivered through a conduit 116 into a second chamber 118, being subjected during the transmission to the action of a heat extractor as indicated at 120. Treatment gases, such for example as CO2 and steam may be introduced into the intermediate chamber 118, and the solid reaction products again transmitted by means of a conduit 122 into a further reaction chamber, as indicated at 124, into which fuel gas and air may be introduced, to effect a combustion operation. From chamber 124 the thus treated lime or dolomite is delivered by means of a conduit 126 and pump 127 back into the upper chamber 114 of the recovery apparatus, being subjected during such transmission to the action of a heat extractor as indicated at 128.

In a hydrogen recovery system such as above set forth, a part of the gaseous hydrogen, along with other gases, are discharged from the chamber 114 through a conduit 130 into a gas separator, as indicated at 132, from which the various gases may be individually discharged through conduits as indicated at 134; the hydrogen being discharged through a conduit 136 under control of a valve 138. Some of the gaseous hydrogen is also discharged from chamber 118 into a gas separator 142 from which other gases may be discharged through a conduit 144 and from which gaseous hydrogen may be discharged through a conduit 146 controlled by valve 148 interconnecting with the conduit 136. Conduits 136 and 146 are directed by a fan 149 into the hydrogen supply line 104 for the chamber 32 of the heat generator; and makeup hydrogen may additionally be supplied from a supply line 150 under control of a valve 152. The reaction of hydrogen with sulphur, within chamber 32, to form hydrogen sulphide (H2S) is a reversible one. By providing an excess of hydrogen an optimum removal of the sulphur may thus be obtained, and by means of a hydrogen recovery system, as above set forth, an excess of hydrogen may be continuously supplied without undue expense.

From chamber 32, the combined char, with a very considerable amount of the sulphur removed, is transmitted through conduit 58 into the lower burning or combustion chamber 34 of the heat generator, wherein the combined char may be burned, as fuel; and as shown in the drawing, the heat of such combustion is utilized to generate steam within a steam generating system, as indicated at 154. Air, to effect the combustion process, is introduced into the combustion chamber 34 from a supply line 156, under control of a valve 158, to a fluidizing head 160, which supplies combustion air, and also uidizes the fuel bed within chamber 34, for maximum burning efficiency.

By reason of the arrangement thus provided, it will be seen that the combined char may be burned, as fuel, directly within the heat generator, thus making unnecessary the mechanical transmission of the combined char to a remote burning location, with its incident expense and heat loss. The transmission of the products of combustion from the chamber 34 may be effected through an exhaust line or flue 162, under control of a valve 164; and such exhaust gases will have a minimum of SO2, by reason of the sulphur elimination chamber 32, as previously described. Exhaust line or flue 162 may lead, if desired, into any suitable secondary combustion system. Ash is discharged from the combustion chamber 34 through an exhaust line 166, under control of a valve 168.

A further reaction may also be effected within the reaction chamber 32, between the hydrogen and the carbon of the combined char, to form methane (CH4). AS this reaction proceeds, the combined char is in effect gasified by the hydrogen thus providing, in effect, a coal gasification system. By holding the combined char within chamber 32 for longer periods, and at higher temperatures and pressures, a greater gasification may be effected, and in this manner the amount of carbon gasification in relation to the amount of combined char transmitted to the combustion chamber 34 may be controlled, in accordance with optimum desired conditions. Since the reaction between H2 and carbon in the l6002000 F. temperature range is highly exothermic, controlled quantities of steam may be added with the incoming hydrogen to achieve additional sulphur removal and gasification of the carbon, while also controlling the temperature of the fluidized bed in the desired range. To this end a valve 170, suitably remotely controlled, may be provided in the transmission line S8 between the chambers 32 and 34.

Cyclone dedusters (not shown) are preferably installed in the gas outlet lines leading from the oil fluid coker, the coal devolatilizer, and the heat generator; and from the vessels 114, 1118 and 124 of the H2 recovery system, to effect solid material separation and thus inadvertent withdrawal of solid matter with the gas from the system.

It will be seen that in accordance with the lime or dolomite hydrogen recovery system herein provided, there is a mixing of the dolomite or lime only with the HZS gas from which the hydrogen is to be recovered. The linvention thus eliminates the mixing of dolomite or lime with coal char or combined char, with its incident difiiculties and the incident separat-ion steps which would thus be required.

It will be seen that the invention thus provides, in a system for producing combined char from coal and oil, for the direct burning of the combined char, or carbonaceous product, within the heat generator within which the product is formed, for maximum combustion efficiency. Means is further provided for maximum removal of sulphur from the fuel, before burning; and means is still further providing for effecting a gasification of the fuel, in a desired percentage, as a part of the fuel production system.

The invention is claimed as follows:

1. The method of treating coal and oil which comprises, separately subjecting coal in a first treatment zone to the action of heat to devolatilize the coal and produce a coal char, separately subjecting oil in a second treatment zone to the action of heat to crack the oil and produce a fluid coke, mixing the char and fluid coke while subjected to the action of heat to provide a carbonaceous product the individual particles of which comprise combined coal char and oil fluid coke, recirculating the mix directly into said first and second treatment zones, and subjecting the carbonaceous product while heated to the action of hydrogen to react with the sulphur therein to reduce the sulphur content of the carbonaceous product.

2. The method of treating coal and oil as defined in claim 1, wherein the hydrogen is applied to the carbonaceous product under heat and high pressure.

3. The method of treating coal and oil as defined in claim 1, wherein the hydrogen is recirculated in a continuous cycle into contaci with the carbonaceous product.

4. The method of treating coal and oil which comprises, separately subjecting coal in a first treatment zone to the action of heat to devolatilize the coal and produce a coal char, separately subjecting oil in a second treatment zone to the action of heat to crack the oil and produce a fluid coke, mixing the char and fluid coke while subjected to the action of heat to provide a carbonaceous product the individual particles of which comprise combined coal char and oil fiuid coke, recirculating the mix directly into said first and second treatment zones, and subjecting the carbonaceous product while heated to the action of hydrogen to react with the sulphur therein to reduce the sulphur content of the carbonaceous product.

5. The method of treating coal and oil as defined in claim 4, wherein the hydrogen is applied to the carbonaceous product under heat and pressure.

6. The method of treating coal and oil as defined in claim 4, wherein the hydrogen is recirculated in a continuous cycle into contact with the carbonaceous product.

7. The method of treating coal and oil which comprises, separately subjecting coal in a first treatment zone to the action of heat to devolatilize the coal and produce a coal char, separately subjecting oil in a second treatment zone to the action of heat to crack the oil and produce a fluid coke, mixing the char and fluid coke while subjected to the action of heat to provide a carbonaceous product the individual particles of which comprise combined coal char and oil fluid coke, recirculating the mix directly into said first and second treatment zones, and iburning the carbonaceous product while it retains its sensible heat.

8. The method of treating coal and oil as defined in claim 7, wherein the burning of the carbonaceous product is effected under pressure.

9. Apparatus for treating coal and oil comprising, a coal devolatilizer defining a first chamber within which coal is subjected to the action of heat to devolatilize the coal, and oil fluid coker defining a second chamber within which oil is subjected to the action of heat to crack the oil and produce a fiuid coke, a heat generator defining a third chamber within which the devolatilized coal and oil fluid coke are mixed and reacted in the presence of air to generate heat and form a carbonaceous product the individual particles of which comprise combined coal char and oil fiuid coke, means for recirculating the devolatilized coal and oil fluid coke between said first, second, and third chambers, and means for supplying hydrogen to the heat generator.

10. Apparatus as defined in claim 9, wherein said coal devolatilizer, said oil fluid coker and said heat generator are maintained under pressure.

11. Apparatus for treating coal and oil comprising, a coal devolatilizer defining a first chamber within which coal is subjected to the action of heat to devolatilize the coal, an oil fluid coker defining a second chamber within which oil is subjected to the action of heat to crack the oil and produce a fluid coke, and a heat generator defining a third chamber within which the devolatilized coal and oil fluid coke are mixed and reacted in the presence of air to generate heat and form a carbonaceous product the individual particles of which comprise combined coal char and oil fiuid coke, said heat generator chamber being sectionalized with the sections in cornmunication to subject the carbonaceous product therein to sequential processing steps, one section of said heat generator chamber being provided with means to supply hydrogen to the carbonaceous product therein.

12. Apparatus for treating coal and oil as defineddn claim 11, wherein one section of said heat generator is provided with means to effect the burning of the carbonaceous product therein.

13. The method of treating coal and oil as defined in claim 1, wherein steam is applied to the carbonaceous product with the hydrogen', and the hydrogen is recovered by subjecting the hydrogen sulphide formed to the action of a hydrogen separating agent such as dolomite or lime.

l14. Apparatus for treating coal and oil comprising, a coal devolatilizer defining'a first chamber within which coal is subjected to the action of heat to devolatilize the coal, an oil fluid coker defining a second chamber within which oil is subjected to the action of heat to crack the oil and produce a fluid coke, and a heat generator defining a third chamber within which the devolatilized coal and oil fluid coke are mixed and reacted in the presence of air to generate heat and form a carbonaceous product the individual particles of which comprise combined coal char and oil fiuid coke, means for recirculating the dcvolatilized coal and oil fluid coke between said first, second, and third chambers, and means within the heat generator for burning the carbonaceous product therein.

References Cited (Other references on following page) 7 UNITED STATES PATENTS 8 OTHER REFERENCES Minet 201-31 Ser. No. 801,460, February 1969, Singh, copending Feldkirchner et al. 48-197 application. Gorin et al. 201-17 Aspegren 201-28 X 5 NORMAN YUDKOFF, Primary Examiner Smith 201--28 X D. ED ARD Wennsky 201 28 W S Asslstant Examiner Welinsky 2101-28 U S CL XR. S' h 201--23 im et aL 1 17 10 zel- 23, 26, 31, 33; 2oz- 114; 48-197 R, 101 Nelson et a1. 201-17

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