GB1569079A

GB1569079A - Partial oxidation process

Info

Publication number: GB1569079A
Application number: GB2081078A
Authority: GB
Original assignee: Texaco Development Corp
Current assignee: Texaco Development Corp
Priority date: 1978-05-19
Filing date: 1978-05-19
Publication date: 1980-06-11

Description

(54) PARTIAL OXIDATION PROCESS (71) We, TEXACO DEVELOPMENT COR- PORATION, a Corporation organized and existing under the laws of the State of Delaware, United States of America, of 135 East 42nd Street, New York, New York 10017, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a partial oxidation process for making synthesis gas, fuel gas, or reducing gas with superheated steam as by-product.

In the partial oxidation process, the effluent gas stream leaving the gas generator at a temperature in the range of about 815 to 19300C. must be cooled below the equilibrium temperature for the desired gas composition. This is done at present by quenching the effluent gas stream in water, or by cooling the gas stream in a gas cooler, thereby producing saturated steam. Both of these methods of gas cooling result in large increases in entropy and reduced thermal efficiencies. This problem is partially overcome according to the present invention by the production of superheated steam from sensible heat extracted from the hot effluent gas stream leaving the partial oxidation gas generator at its maximum temperature.

Production of saturated steam, but not superheated steam is described in U.S.

Patent No. 3,528,930.

The present invention provides a process for producing gaseous mixtures comprising H2 and CO by the partial oxidation of a fuel, containing carbon and hydrogen with a free-oxygen containing gas at a temperature from 815 to 19300C. and a pressure about 1 to 250 atmospheres absolute in the reaction zone of a free-flow noncatalytic gas generator, which comprises removing sensible heat from an unquenched effluent gas stream from the generator by passing it in sequence through first and second heat exchange zones, the sensible heat removed in said second zone being employed to convert a stream of water into steam by indirect heat exchange, and the sensible heat removed in said first zone being used to convert at least a portion of said steam into superheated steam.At least a portion of the superheated steam produced in accordance with the invention may be continuously recycled to the gas generator, as a dispersant or carrier for the fuel, or as a temperature moderator. Optionally, at least a portion of the superheated steam may be continuously introduced into a steam turbine as the working fluid to produce mechanical work or electrical energy. The high steam superheat temperature results in a higher conversion efficiency. In accordance with the embodiment of the invention the hot effluent gas stream from the partial oxidation gas generator is passed successively through first and second heat exchange zones in series. A continuous stream of steam is produced in the second heat exchange zone i.e. in a gas cooler.Then in the first heat exchange zone, the stream of steam is converted into a continuous stream of superheated steam by heat exchange with the stream of hot effluent gas leaving the gas generator.

Another embodiment of the process involves three heat exchange zones. In the first heat exchanger, a continuous stream of heat transfer fluid absorbs a portion of the sensible heat in the stream of hot effluent gas leaving the gas generator. The heated heat exchange fluid is then continuously introduced into a third heat exchange zone (acting as a superheater) in heat exchange with a continuous stream of steam. The steam was previously produced in the second heat exchanger by heat exchange between water and the effluent gas stream leaving the first heat exchanger.

A continuous stream of superheated steam may be removed from the superheater, for use in the process or for export. Advantageously, the superheated steam may be at a pressure which is greater than that in the gas generator.

According to another embodiment of the invention, a portion of steam or of heat transfer fluid is continuously bled into the effluent gas stream in the first heat exchange zone.

In one form of this embodiment, the hot effluent gas from the gas generator is passed directly through a first heat exchange zone comprising a shell and tube heat exchanger in indirect heat exchange with a continuous stream of steam having a higher pressure than the effluent gas, thereby converting the steam into a continuous stream of superheated steam while simultaneously reducing the temperature of the effluent gas. A portion of the steam is continuously bled into the effluent gas through openings in the walls of the tubes, thereby providing a protective sheath of steam between the surface of the tubes, and the stream of effluent gas passing through the first heat exchange zone.

Advantageously, the steam produced by the process of this invention is at a higher pressure than that of the effluent gas.

Accordingly, the steam will flow through the openings in the walls of the tubing without further compression.

In another form of this embodiment, the hot effluent gas leaving the gas generator, optionally through a solids separation zone, at substantially the same temperature and pressure as in the generator is passed directly through a first heat exchange zone comprising a shell and tube heat exchanger in heat exchange with a continuous stream of gaseous heat transfer fluid thereby cooling said hot effluent gas stream while simultaneously heating said gaseous heat transfer fluid. A portion of the gaseous heat transfer fluid is continuously bled into the effluent gas stream through openings in the walls of the tubes and headers, if any, of the heat exchangers thereby providing a protective sheath or curtain of gaseous heat transfer fluid between the surfaces of the tubes and headers, if any, and the effluent gas stream.The heated gaseous heat transfer fluid leaving the first heat exchange zone is introduced into a third heat exchange zone in indirect heat exchange with the stream of steam from the second heat exchange zone thereby cooling the gaseous heat transfer fluid and producing a stream of superheated steam. The mixture of effluent gas and the bleed-stream portion of gaseous heat transfer fluid from the first heat exchange zone is cleaned, thereby producing a raw effluent product gas. A portion of the raw clean effluent product gas, as make-up, is mixed with the cooled heat transfer fluid leaving the third heat exchange zone, and the gaseous mixture is introduced into the first heat exchange zone as the gaseous heat transfer fluid.

The invention will be further understood by reference to the accompanying drawings in which Figs. 1 to 4 are schematic representations of preferred embodiments of the process.

The present invention provides an improved continuous partial oxidation gasification process for producing raw synthesis gas, reducing gas, or fuel gas along with valuable superheated steam as by-product.

The aforesaid gas streams comprise H2, CO, and generally one or more of the groups H2O, CO2, H2S, COS, CH4, N2, Ar and particulate carbon.

A continuous effluent gas stream of synthesis gas, reducing gas or fuel gas is produced in the refractory lined reaction zone of a separate free-flow unpacked noncatalytic partial oxidation fuel gas generator.

The gas generator is preferably a vertical steel pressure vessel, such as shown in the drawing and described in U.S. Patent No.

2,992,906.

A wide range of combustible carbon- and hydrogen-containing organic materials may be reacted in the gas generator with a freeoxygen containing gas optionally in the presence of a temperature moderating gas to produce said effluent gas stream.

Any fuel containing carbon and hydrogen and optionally other elements, that can generally be employed in a partial oxidation gas generator, including gaseous, liquid, and solid hydrocarbons, carbonaceous materials, and mixtures thereof, can be used in accordance with the present invention. In fact, substantially any combustible carbon containing organic material, fossil fuel, or slurries thereof, may be employed.For example, there are (1) pumpable slurries of solid carbonaceous fuels, such as coal, lignite, particulate carbon, petroleum coke, concentrated sewer sludge, and mixtures thereof; (2) gas-solid suspensions, such as finely ground solid carbonaceous fuels dispersed in either a temperature moderating gas or a gaseous hydrocarbon; and (3) gas Iiquid-solid dispersions, such as atomized liquid hydrocarbon fuel, or atomized water and particulate carbon, dispersed in a temperature-moderating gas. The hydrocarbonaceous fuel may have a sulfur content in the range of O to 10% by weight and an ash content in the range of 0 to 15% by weight.

The term liquid hydrocarbon, as used herein to describe suitable liquid feedstocks, is intended to include various materials, such as liquefied petroleum gas, petroleum distillates and residues, gasoline, naphtha, kerosine, crude petroleum, asphalt, gas oil, residual oil, tar-sand oil and shale oil, coal derived oil, aromatic hydrocarbon (such as benzene, toluene, xylene fractions), coal tar, cycle gas oil from fluid-catalytic-cracking operation, furfural extract of coker gas oil, and mixtures thereof. Gaseous hydrocarbon fuels, as used herein to describe suitable gaseous feedstocks, include methane, ethane, propane, butane, pentane, natural gas, watergas, coke-oven gas, refinery gas, acetylene tail gas, ethylene off-gas, synthesis gas, and mixtures thereof.Both gaseous and liquid feeds may be mixed and used simultaneously, and may include paraffinic, olefinic, naphthenic, and aromatic compounds in any proportion.

Also usable as fuels containing carbon and hydrogen are oxygenated hydrocarbonaceous organic materials including carbohydrates, cellulosic materials, aldehydes, organic acids, alcohols, ketones, oxygenated fuel oil, waste liquids and by products from chemical processes containing oxygenated hydrocarbonaceous organic materials, and mixtures thereof.

The fuel feed may be at room temperature or it may be preheated, for example to a temperature from 315 to 650 C. e.g. up to 430"C. but preferably below its cracking temperature. Preheating of the fuel may be accomplished by non-contact heat exchange, or direct contact with superheated or saturated steam produced later in the process.

The fuel may be introduced into the burner in liquid phase or in a vaporized mixture with a temperature moderator. Suitable temperature moderators include superheated steam, saturated steam, unsaturated steam, water, CO2-rich gas, a portion of the cooled exhaust from a turbine employed downstream in the process, nitrogen in air, byproduct nitrogen from a conventional air separation unit, and mixtures of the aforesaid temperature moderators.

The use of a temperature moderator to moderate the temperature in the reaction zone depends in general on the carbon on hydrogen ratio of the feedstock and the oxygen content of the oxidant stream. A temperature moderator may not be required with some gaseous hydrocarbon fuels, but one is generally used with liquid hydrocarbon fuels and with substantially pure oxygen. The temperature moderator may be introduced in admixture with either or both reactant streams. Alternatively, the temperature moderator may be introduced into the reaction zone of the gas generator by way of a separate conduit in the fuel burner.

From 0 to 100% of the superheated steam produced subsequently in the process may be used to preheat and disperse the liquid bydrocarboneaceous fred, or to preheat and entrain the solid carbonaceous fuels that rnay be introduced into the gas generator.

The weight ratio of total amount of H,O to fuel introduced into the reaction zone of the gas generator is generally in the range of 0 to 5.

When comparatively small amounts of H2O are charged to the reaction zone, for example through the burner to cool the burner tip, the H2O may be mixed with either the fuel, the free-oxygen containing gas, the temperature moderator, or combination thereof. In such case, the weight ratio of water to fuel may conveniently be in the range of 0.0 to 1.0, and more preferably 0.0 to 0.2.

The term "free-oxygen containing gas", as used herein is intended to include air, oxygen-enriched air, i.e. greater than 21 mole % oxygen, and substantially pure oxygen, i.e. greater than 95 mole % oxygen, (the remainder comprising N2 and rare gases). Free-oxygen containing gas may be introduced into the burner at a temperature in the range of ambient to 985"C. The ratio of free oxygen in the oxidant to carbon in the feedstock (O/C, atom/atom) is preferably in the range of about 0.7 to 1.5.

The feedstreams are introduced into the reaction zone of the fuel gas generator by means of fuel burner. Suitably, an annulustype burner, such as described in U.S.

Patent No. 2,928,460 may be employed.

The feedstreams are reacted by partial oxidation without a catalyst in the reaction zone of a free-flow gas generator at an autogenous temperature in the range of about 815 to 1930C and at a pressure in the range of about 1 to 250 atmospheres absolute. The reaction time in the fuel gas generator is generally 1 to 10 seconds. The effluent stream of gas leaving the gas generator may comprise CO, H2, CO2, H2O, CH4, N2, Ar, H2S and COS. Unreacted particulate carbon (on the basis of carbon in the feed by weight) is generally about 0.2 to 20% by weight from liquid feeds, but is usually negligible from gaseous hydrocarbon feeds.

The specific composition of the effluent gas is dependent on actual operating conditions and feedstreams. Synthesis gas substantially comprises H2 + CO; all or most of the H2O and CC > 2 are removed for reducing gas; and the CH4 content may be maximized for fuel gas.

Preheating of the fuel may be accomplished by indirect heat exchange or direct contact with superheated, saturated, or unsaturated steam as produced in the process according to the invention.

A continuous stream of hot effluent gas, at substantially the same temperature and pressure as in the reaction zone leaves from the axial exit port of the gas generator and is then introduced directly to a first heat exchange zone. Optionally, a solids separation zone (not shown in the drawing) may be inserted between the exit port of the gas generator and the first heat exchange zone. The solids separation zone may comprise a free-flow catch-pot i.e. slag chamber which may be inserted in the line before the first heat exchanger.By this means at least a portion of any solid matter i.e. particulate carbon, ash, slag, refractory, and mixtures thereof that may be entrained in the hot effluent gas stream, or which may flow from the gas generator i.e. slag, ash, bits of refractory, may be separated from the effluent gas stream and recovered with very little, if any, pressure drop in the line.

A typical slag chamber that may be employed is shown in Fig. 1 of the drawing for U.S. Patent No. 3,528,930.

A portion of the sensible heat in the unquenched effluent gas stream leaving the gas generator or the solids separation zone is recovered in a first heat exchange zone.

This heat is used to convert steam, produced elsewhere in the process, into superheated steam at a pressure above the pressure in the gas generator. As shown in the accompanying drawings, in Figs. 1 and 3 the superheated steam in lines 39 and 42 is produced in heat exchanger 16 by heat exchange between the effluent gas stream from the gas generator and steam. In Figs.

2 and 4, the superheated steam in line 39 is produced in heat exchanger 55 by heat exchange between a heat transfer fluid and steam. The heat transfer fluid was previously heated in heat exchanger 16 by heat exchange with the effluent gas stream from the gas generator.

In Fig. 1 of the drawings, the hot effluent gas stream from the generator passes in noncontact heat exchange with a stream of steam produced in a second heat exchange zone located immediately downstream. By definition, the word "noncontact" means that there is no mixing between the two gas streams. Preferably, these two streams run in opposite directions i.e. countercurrent flow. However, they may run in the same direction i.e. direct flow. In Fig. 1 there is depicted a conventional shell and tube heat exchanger 16 with steam entering and superheated steam leaving the shell side and with the hot effluent gas passing through tubes or multiple coils. This arrangement of streams may be reversed, and the hot effluent gas may flow on the shell side. Any suitable heat exchanger that is capable of withstanding the temperatures and pressures of the fluids may be used.Heat resistant metals and ceramics may be employed as construction materials.

The stream of steam to be converted into superheated steam enters the first heat exchanger at a temperature in the range of 150 to 3750C., and a pressure in the range of about 4 to 260 atmospheres absolute. The superheated steam leaves the first heat exchanger at a temperature in the range of about 400 to 6000C., and a pressure in the range of about 4 to 260 atmospheres absolute.

Advantageously, the superheated steam may be produced at a pressure which is greater than the pressure in the reaction zone of the gas generator. The high steam superheat temperature results in a high conversion efficiency when said superheated steam is employed as the working fluid in an expansion turbine for producing mechanical power or electrical energy. The hot effluent gas stream from the gas generator or solids separation zone at substantially the same temperature and pressure as in the reaction zone enters the first heat exchanger at a temperature in the range of about 815 to 1930"C. and a pressure in the range of about 1 to 250 atm. abs., such as 3.5 to 250 atm. abs.

The partially cooled effluent gas stream may leave the first heat exchange zone at a temperature in the range of about 315 to 1430"C. and a pressure in the range of about 3.5 to 250 atmospheres absolute and enters a second heat exchange zone i.e. gas cooler 23 with substantially no reduction in temperature and pressure where it passes in noncontact heat exchange with boiler feed water.

The raw effluent gas stream leaves the second heat exchange zone at a temperature in the range of about 160 to 370"C. and a pressure which is substantially the same as in the reaction zone of the gas generator, less ordinary pressure drop in the lines, any solids removal zone, and first and second heat exchange zones i.e. total pressure drop may be about 2 atmospheres absolute or less. The raw effluent gas stream may comprise (in mole%) H 70 to 10, CO 15 to 57, CO 0 to 5, H2O 0 to 20, No 0 to 75, Ar o to 1.0, CH4 0 to 25, H2S 0 to 2.0, and COS 0 to 0.1. Unreacted particulate carbon (on the basis of carbon in the feed by weight) may be about 0 to 20% by weight.

Optionally, the raw effluent gas stream leaving the second heat exchange zone may be sent to conventional gas cleaning and purification zones downstream where unwanted constituents may be removed.

The boiler feed water enters the second heat exchange zone at a temperature in the range of about ambient to 3600C. and leaves as unsaturated or saturated steam at a temperature of about 150 to 3750C and 4.5 to 260 atmospheres absolute. Advantageously, the unsaturated or saturated steam may be produced at a pressure which is greater than the pressure in the reaction zone of the gas generator. While countercurrent flow is preferred in the second heat exchanger 23, as shown in Fig. 1, direct flow may be employed. Further, in another embodiment, the stream of steam may be produced in the tubes while the effluent gas stream is passed through the shell side.

From about 0 to 100% by weight of the steam produced in the second heat exchange zone is passed into the first heat exchange zone to produce superheated steam having a pressure greater than the pressure in the gas generator. Optionally, a portion of the steam may be used elsewhere in the process or exported. Superheated, saturated, or unsaturated steam produced in the process may be used to provide heat. For example steam may be used to preheat the feedstreams to the gas generator. In this manner, hydrocarbonaceous fuel may be preheated to a temperature up to about 4300C, but below its cracking temperature, with at least a portion of the steam produced by the subject process. It may also be used in the gas generator as a temperature moderator.

At least a portion of the superheated steam produced in the process may be introduced into the partial oxidation gas generator, where it may react and thereby contribute to the amount of hydrogen in the effluent gas stream. Further, the thermal efficiency of the process is improved.

Condensation problems that may result when steam and fuel are mixed together may be avoided by using superheated steam.

Advantageously, a portion fo the super heated steam may be used as the working fluid in a turbocompressor to compress air feed to an air separation unit for producing substantially pure oxygen (95 mole % or more). At least a portion of this oxygen may be introduced into the gas generator as the oxidant reactant. The superheated steam may also be used as the working fluid in a turboelectric generator. Starting with super heated steam at a very high temperature level, and converting the heat into elec tricity, favourably affects the conversion efficiency.

The first and second heat exchange zones are shown in the drawings as two separate heat exchangers 16 and 23 that are joined together. The advantages of this scheme are simplification of the design and reduction of the size of each heat exchanger, thereby reducing equipment costs. Heat exchange units of conventional design may be assem bled. System down-time may be minimized if one of the units has to be replaced for maintenance or repair. In another embodi ment, the first and second heat exchange zones may be contained in a common shell.

Another embodiment of the invention is shown in Fig. 2 of the drawings. There the hot effluent gas stream from the gas gener ator or, optionally, from a free-flow solids, slag, or both separation zone and at sub stantially the same temperature and pres sure as that in the reaction zone, enters the first heat exchanger 16 as in the embodiment shown in Fig. I of the drawings.The effluent gas stream, however, passes in noncontact heat exchange with a comparatively cool heat transfer fluid, which is thereby raised to a temperature in the range of about 985 to 1540"C. Simultaneously, the effluent gas stream is cooled and leaves the first heat exchange zone at a temperature in the range of about 315 to 14300 C. and a pressure in the range of about 2.7 to 255 atmospheres absolute and directly enters a second heat exchange zone i.e. gas cooler 23 at substantially the same temperature and pressure as it leaves heat exchanger 16.

In gas cooler 23, the effluent gas stream passes in noncontact heat exchange with boiler feed water. The boiler feed water enters at a temperature in the range of about ambient to 360"C. and leaves as saturated or unsaturated steam at a temperature of about 150 to 375"C. and a pressure of about 4.5 to 260 atmospheres absolute. Advantageously, the saturated or unsaturated steam may be produced at a pressure which is greater than the pressure in the reaction zone of the gas generator.

The effluent gas stream leaves gas cooler 23 at a temperature in the range of about 160 to 370"C. and at a pressure which is about the same as in the reaction zone of the gas generator, less ordinary pressure drop in the lines and vessels.

Simultaneously, with the heat exchange going on in heat exchangers 16 and 23, a continuous stream of superheated steam at a temperature in the range of about 400 to 600"C. and a pressure in the range of about 4.5 to 260 atmospheres absolute is produced in a third heat exchange zone i.e.

heat exchanger 55, by noncontact heat exchange between a continuous stream of steam from the previously described second heat exchange zone 23, and a continuous stream of said heat transfer fluid from the first heat exchange zone 16. Advantageously, the superheated steam may be produced with a pressure that is greater than the pressure in the reaction zone of the gas generator.

The heat transfer fluid enters heat exchanger 55 from heat exchanger 16 at a temperature in the range of about 985 to 1540"C., leaves heat exchanger 55 at a temperature in the range of 455 to 12050C., and at substantially the same temperature, and is circulated into heat exchanger 16, where it passes in noncontact heat exchange with the effluent gas stream from the gas generator, as previously described. By this means, the sensible heat in a stream of effluent gas from the gas generator may be used to produce superheated steam in a comparatively clean environment.

A portion of the raw effluent gas stream may be used as the heat transfer fluid.

Optionally, at least a portion of the raw effluent gas stream may be cleaned and purified by conventional means to remove unwanted constituents. At least a portion of this product gas may be used as the heat transfer fluid. For example, mixtures of H,+CO having the following composition (in mole%) may be produced: H2 10 to 48, CO 15 to 48, and the remainder Ns+Ar Further, substantially pure H2, i.e.

98 mole % or more, for use as the heat transfer fluid may be prepared from the effluent gas stream by well known gas cleaning and purification techniques, including the water-gas shift reaction.

The heat transfer fluid circulated between heat exchangers 16 and 55 may be either in a gaseous or liquid state, and may be H2O, helium, nitrogen, argon, hydrogen, or a mixture comprising H2 + CO. Alternatively, the heat transfer fluid may be sodium, potassium, mercury, or sulphur, in gaseous or liquid state, so that the heat transfer fluid may be compressed or pumped depending in the operating conditions of temperature and pressure and the phase of the heat transfer fluid. Cooling these heat transfer fluids to below their solidification temperatures is therefore to be avoided.

In another embodiment, the heat transfer fluid may change state during the heat exchange. For example, in heat exchanger 16, a heat transfer fluid in liquid phase may be converted into the vapor phase. Then in heat exchanger 55, the heat transfer fluid may be condensed back into the liquid phase, which is then pumped into heat exchanger 16.

Conventional shell and tube type heat exchangers may be used. As described above, the two separate streams passing in heat exchange with each other may be passed in the same or opposite directions, and either stream may be passed through the tubes while the other may be passed on the shell side. By properly insulating the lines, gas generator 1, and heat exchangers 16, 23 and 55, the temperature drop between the pieces of equipment may be kept very small i.e. less than 5"C. Heat resistant metals and refractories are used as construction materials.

In Fig. 3 of the drawings there is depicted a first shell and tube heat exchanger 16A which comprises a plurality of tubes or coils. Optionally, headers may be placed inside or outside the shell. The tubes and optionally the headers, if any, are provided with openings in the walls through which at least a portion e.g. about 1 to 50 volume %, more preferably 3 to 25 volume % of the steam passing up through the shell may be bled from outside the tubes to inside the tubes while simultaneously superheating the remainder of the steam on the shell side.

Once inside the tubes or headers, the bleed steam mixes with the effluent gas stream passing directly through the tubes from the gas generator at a slightly lower pressure i.e. about 0.35 to 3.5 atmospheres less.

Before this mixing, however, the comparatively cool bleed steam forms a continuously flowing protective sheath or curtain between the inside surface of the tubes and the effluent gas stream passing therethrough at a temperature in the range of about 815 to 19300C. In a similar manner, a continuously flowing protective sheath or curtain of steam may cover the surfaces of the headers, if any, that would ordinarily be contacted by the hot effluent gas stream. By this means the surfaces of the tubes and headers, if any, such as the upstream header, may be cooled and protected against corrosive gas attack, as well as from deposits of ash, slag, and soot.

Alternatively, shell and tube heat exchanger 16A may be arranged so that the hot effluent gas stream from the gas generator passes down through on the shell side while the steam passes through the tubes and any headers. At least a portion of the steam, e.g. 1 to 50 vol. %, more preferably 3 to 25 vol. %, may be bled from inside the tubes and headers, if any, to the outside.

Further, the bleed steam provides a protective sheath between the outside of the tubes and headers, if any, and the effluent gas stream from the gas generator. The remainder of the steam, passing through the tubes is superheated.

Optionally, the downstream ends of the tubing and the downstream header, if any, may have no holes or fewer bleed holes, since the temperature of the effluent gas stream at his point, will have been reduced by heat transfer to below the temperature at which corrosion may take place with H2S in the effluent gas stream. For similar reasons, high class materials will only be required in the upstream (hot) end of the tubes.

The openings in the walls of the tubes and headers, if any, may be small diameter holes in the range of about 0.025 to 1.6 mm. The holes are positioned around the periphery of the tubing and the number is such that sheath flow is allowed to bleed out around the entire periphery of the tube. Two dissimilar metals may be joined by a close fitting slip joint, thereby permitting thermal expansions and bleeding. For example, longi tudinal spacing ridges on the male end of the slip joint would provide a gap that is controlled for a design leakage flow when the joint is assembled. Heat resistant porous materials including metals and ceramics, mav also be used as construction materials.

The stream of steam to be converted into superheated steam enters the first heat exchanger at a temperature in the range of about 150 to 3750C, and a pressure in the range of about 4.5 to 260 atmospheres absolute. The superheated steam leaves the first beat exchanger at a temperature in the range of about 400 to 6000C. and a pres sure in the range of about 4 to 260 atmo sores absolute. Advantageously, the superbested steam may be produced at a pres sure which is greater than the pressure in the reaction zone of the gas generator.

kordingly, the steam will flow through the openings iin the wall of the heat exchanger tubes without being compressed.

While it passes through the first heat exchange zone, the water content of the gas stream stream may have increased in the range of from 1 to 50, e.g. about 3 to 25 mole % H2O. Advantageously, when the effluent gas stream leaving the first heat snge zone is subjected to water-gas shirt reaction downstream in the process, it is desirable to bleed sUcient steam into the uent gas stream in the first heat exeiwige for the mole ratio H,O/CO of the gaseous mixture to be in the range from 0.5 to 8.

In order to produce the steam for super heaflag in the first heat exchange zone, the partially cooled effluent gas stream leaving Xe first heat exchange zone, e.g. at a temperature in the range of about 315 to 1430 C. and a pressure in the range of Xout 3 to 250 atmospheres absolute and then enter a second heat exchange zone i.e.

gas cooler 23 with substantially no reduction in temperature and pressure where it paSses in rercontact heat exchange with ,boiler feed water.

TRmperature and pressure conditions in the second heat exchange zone will fall generally within the same temperature and pressure ranges as in the other embodiments of the invention.

Anther embodiment of the invention is shown in Fig. 4 of the drawings. There the Wot effluent gas stream from the gas generator or, optionally, from a free-flow solids, slag, or both separation zone enters heat exchanger 1 6A which is a shell and tube eat exchanger whose construction is similar to that described previously in connection with heat exchanger 16A in Fig. 3. Instead of * steam, however, at least a portion of gaseous heat transfer fluid is bled from inside the tubes or header, if any, to the outside, or the reverse, and mixed with the surrounding hot effluent gas stream passing through heat exchanger 16A.A comparatively cool continuously flowing protective sheath or curtain of heat transfer fluid is thereby placed between the surfaces of the tubes and headers, if any, and the surround bqg effluent gas stream from the gas gener . The unbled portion of the gaseous lasat transfer fluid is heated to a temperature in the range of about 700 to 15409C.

in heat exchanger 16A and is then introduced into a third heat exchanger 55 where it passes in indirect heat exchange with steam, thereby producing superheated steam.

Simultaneously, the effluent gas stream passing through the first heat exchange zone i.e. 16A is cooled and leaves at a temperature in the range of 315 to 14300C and a pressure in the range of about 3 to 250 atmospheres.

The cooled effluent gas stream leaving the first heat exchange zone can be cleaned by conventional methods to remove any unwanted entrained solids i.e. particulate carbon, ash, and optionally the gas stream may be purified by removing acid-gases i.e.

CO2, H2S, COS. At least a portion e.g. 1 to 50 vol. %, more preferably 3 to 25 vol.

% of the clean and optionally purified effluent gas stream at a temperature in the range of about 35 to 3700C. is recycled and mixed with the cooled heat transfer fluid leaving said third heat exchange zone to make-up for the clean effluent gas stream that bleeds through heat exchanger 16A into the surrounding effluent gas stream passing through the first heat exchange zone. The gas mixture at a temperature in the range of about 90 to 13150C. say 315 to 7600C, is then passed through heat exchanger 16 as the gaseous heat transfer fluid, as previously described.

Conditions in the second heat exchange zone and the temperature and pressure of the boiler feed water, and of the steam produced are generally within the same ranges as in the other embodiments of the invention.

Simultaneously, with the heat exchange going on in heat exchangers 16A and 23, a continuous stream of superheated steam at a temperature in the range of about 400 to 600"C. and a pressure in the range of about 4.5 to 260 atmospheres absolute is produced in a third heat exchange zone, i.e. heat exchanger 55, by noncontact heat exchange between a continuous stream of steam from the second heat exchange zone 23 and a continuous stream of heat transfer fluid from the first heat exchange zone 16A.

Advantageously, the superheated steam may be produced with a pressure that is greater than the pressure in the reaction zone of the gas generator. The heat transfer fluid enters heat exchanger 55 from heat exchanger 16A for example at a temperature in the range of about 425 to 15400 C, more preferably 425 to 985 C leaves exchanger 55 at a temperature of, for example 250 to 13700C, more preferably 310 to 815 C is mixed with a recycle make-up portion of the effluent product gas stream at a temperature in the range of about 35 to 370"C. and a pressure above that of the raw effluent gas stream and is then introduced into heat exchanger 16A, where it passes in noncontact heat exchange with the effluent gas stream from the gas generator, as previously described.

A more complete understanding of the invention may be had by reference to the accompanying drawings which show the previously described embodiments. All of the lines and equipment are preferably insulated to minimize heat loss. In the drawings, like numbers are used for like portions of the apparatus.

Referring to Fig. 1 of the drawings free-flow noncatalytic partial oxidation gas generator 1 line with refractory material 2 has an upstream axially-aligned flanged inlet port 3, a downstream axially-aligned flanged outlet port 4, and a unpacked reaction zone 5. Annulus type burner 6, with centre passage 7 in alignment with the axis of gas generator 1, is mounted in inlet port 3. Centre passage 7 has an inlet 8, and a converging conically shaped nozzle 9 at the tip of the burner. Burner 6 is also provided with concentric coaxial annulus passage 10 that has an inlet 11 and a conically shaped discharge passage 12. Burners of other design may also be used.

Connected to outlet port 4 is the flanged inlet 15 of a shell and tube high temperature heat exchanger 16 of conventional design, having internal tubes or multiplecoils 17, a shell side 20, and a downstream flanged outlet 21. Optionally, a free-flow solids or slag separator (not shown in the drawing), which produces little or no pressure drop. may be inserted in the line between outlet 4 of gas generator 1 and inlet 15 of heat exchanger 16. Connected to outlet 21 of heat exchanger 16 is the upstream flanged inlet 22 of shell and tube gas cooler 23, of conventional design, having internal tubes 24, shell side 25, and a downstream flanged outlet 26.

A continuous stream of fuel in liquid or vapor form, or a pumpable slurry of a solid fuel, as previously described, may be introduced into the system by way of line 30, and optionally mixed with a continuous stream of superheated steam from line 31, or a stream of saturated steam from line 53, in a mixer (not shown). The feed mixture is then passed through line 33, inlet 11, annulus passage 10, and discharge passage 12 of burner 6 into reaction zone 5 of partial oxidation gas generator 1.

Simultaneously, a continuous stream of free-oxygen containing gas as previously described, from line 34 is passed through centre passage 7 and nozzle 9 of burner 6, into reaction zone 5 of gas generator 1 in admixture with fuel and steam.

The continuous stream of effluent gas leaving partial oxidation gas generator by way of outlet 4 is passed through heat exchanger 16 in non-contact indirect heat exchange with a counteiflowing stream of steam produced in gas cooler 23. For example, the steam passing upwardly on the shell side 20 of heat exchanger 16 (also called superheater 16) is converted into superheated steam which leaves by way of outlet 38, line 39, valve 41 and line 31, and is mixed with the hydrocarbonaceous fuel from line 30 in line 33. Optionally, a stream of superheated steam may be withdrawn from superheater 16 by way of line 42, valve 43, and line 44, and introduced into a steam turbine as the working fluid.

The partially cooled effluent gas stream leaves superheater 16 through outlet 21, and enters waste heat boiler 23 by way of inlet 22. In passing through gas cooler 23, the effluent gas stream passes in noncontact indirect heat exchange with a counterflow- ing stream of boiler feed water. The boiler feed water is thereby heated to produce steam by absorbing at least a portion of the remaining sensible heat in the effluent gas stream. Thus, the boiler-feed water in line 45 enters heat exchanger 23 through inlet 46. It passes up on shell side 25, and leaves through outlet 47 and line 48 as steam. The steam enters superheater 16 through inlet 49 and is converted into superheated steam as previously described. Optionally, a portion of the steam is removed from gas cooler 23 by way of outlet 50, line 51, valve 52, and line 53.This steam may be used elsewhere in the system.

The cooled effluent gas stream leaves gas cooler 23 by way of bottom outlet 26 and line 54, and may be sent to conventional gas cleaning and purification zones downstream.

Referring to Fig. 2 of the drawings, the apparatus is similar to that previously described, with the exception of an additional shell and tube heat exchanger 55 containing bottom flanged inlet 56, top flanged outlet 57, internal tubes or coils 58, shell side 59, and side outlet 60. From line 61, a circulator 62, e.g. a pump, compressor, or blower, circulates gaseous or liquid heat transfer fluid through line 63, inlet 64, up through shell side 20 in heat exchanger 16, outlet 65, line 66, and inlet 67 of heat exchanger 55 (also called superheater 55). The hot heat transfer fluid then passes down through shell side 59 and out through bottom outlet 60 for recirculation to heat exchanger 16 and reheating.

Operation of the embodiment shown in Fig. 2 is somewhat similar to that previously described in Fig. 1. The main differences relate to the employing a heat transfer fluid which is circulated between heat exchangers 16 and 55. In heat exchanger 16, the stream of heat transfer fluid is heated by absorb ing a portion of the sensible heat in the effluent gas stream directly from gas generator 1 or directly from a solids and slag separator (not shown in the drawing). As previously described, the stream of heat transfer fluid in heat exchanger 16 passes up through shell side 20 in noncontact indirect heat exchange with the down-flowing continuous stream of hot effluent gas from gas generator 1 in tubes 17.Then in heat exchanger 55, the amount of sensible heat given up by the stream of heat transfer fluid continuously passing down through shell side 59 is sufficient to convert the continuous stream of steam, with which it passes in noncontact indirect heat exchange, into superheated steam. The steam was previously produced in waste heat boiler 23 as described previously for Fig. 1. At least a portion of the steam produced in gas cooler 23 is introduced into superheater 55 by way of outlet 47, line 48 and flanged inlet 56.

Optionally, superheated steam from line 39 or steam from line 53 may be introduced into gas generator 1 as a temperature moderator and as a transport medium for the fuel. Preferably, the effluent gas stream is passed through the tubes in heat exchangers 16 and 23 connected in series.

In the apparatus shown in Fig. 3 of the drawings, the layout of gas generator 1, superheater and gas cooler 23 is generally the same as in Fig. 1, but the heat exchanger (superheater) 1 6A is of somewhat different construction, being shell and tube high temperature heat exchanger 16A, having internal tubes or multiple-coils 17, connected to upstream header 18 and downstream header 19, a shell side 20, and a downstream header 19, a shell side 20, and a downstream flanged outlet 21.

The continuous stream of effluent gas leaving partial oxidation gas generator by way of outlet 4 is passed through heat exchanger 1 6A in heat exchange with a counterflowing stream of steam produced in gas cooler 23. Additional steam from another source may be introduced through lines 27, 28, 29, 32 and 49. At least a portion of the steam passing upwardly on the shell side 20 of heat exchanger 1 6A (also called superheater 16A) is passed through holes 33 in walls of tubing 17 and upstream header 18 and is then mixed with the hot effluent gas stream from gas generator. The remainder of the steam is converted into superheated steam which leaves by way of outlet 38, lines 79, 39, valve 41, line 31. and mixed with the hydrocarbonaceous fuel from line 30 in line 35.Optionally, a stream of superheated steam may be withdrawn from superheater 1 6A by way of line 42, valve 43, line 44, and introduced into a steam turbine 70 as the working fluid, and leaves through line 71. Turbine 70 powers air compressor 72 and optionally electric generator 73. Air enters compressor 70 through line 74 and leaves through line 75. In airseparation zone 76, the compressed air is separated into nitrogen in line 77 and oxygen in line 78. Optionally, superheated steam may be withdrawn from superheater 16A through outlet 38, lines 79 to 80, valve 81, and line 82.

The partially cooled effluent gas stream containing said bleed stream leaves superheater 16A through outlet 21 and enters waste heat boiler 23 by way of inlet 22.

In passing down through gas cooler 23, the mixture of effluent gas stream and bleed steam passes in noncontact indirect heat exchange with a counterflowing stream of boiler feed water. The boiler feed water is thereby heated to produce steam by absorbing at least a portion of the remaining sensible heat in the mixture of effluent gas stream and bleed stream. Thus, the boilerfeed water in line 45 enters heat exchanger 23 through inlet 46. It passes up on shell side 25, and leaves through outlet 47 and line 48 as steam. The steam enters superheater 16A through line 32, inlet 49 and is converted into superheated steam as previously described. Optionally, a portion of the steam is removed from gas cooler 23 by way of outlet 50, line 51, valve 52, and line 53. This steam may be used elsewhere in the system.

The cooled mixture of effluent gas stream and bleed steam leaves gas cooler 23 by way of bottom outlet 26, line 54, and may be sent to conventional gas cleaning, and optionally to a purification zone downstream. The cleaned and optionally purified product gas may be used as synthesis gas, reducing gas, or fuel gas, depending on its composition. For example, clean product gas may be introduced into the combustor of a gas turbine (not shown). The gaseous products of combustion pass from the combustor to an expansion turbine as the working fluid. The turbine may drive a turbocompressor, or a turboelectric generator.

The turbocompressor may be used to compress air for use in the system. The electric generator may provide electrical energy for use in the process.

Referring to Fig. 4 of the drawings, the process is similar to that previously described in connection with Fig. 2, with the exception of cleaning and optional purification zones 91.

A recycle make-up portion of the effluent product gas stream in line 115 is compressed by gas compressor 69 to a greater pressure than that of the raw effluent gas stream leaving gas generator 1. The cooler compressed make-up gas is then mixed in line 68 with the gaseous heat transfer fluid leaving superheater 55 through lower side outlet 60 and line 61. By means of gas circulator 62, the gaseous heat exchange fluid is passed through line 63, inlet 64, and downstream header 13 of shell and tube heat exchanger 16A. There the gaseous heat transfer fluid passes up through a plurality of tubes or coils 17, and then leaves through upstream header 14 and outlet 65. While moving upward through heat exchanger 16A, a portion of the gaseous heat transfer fluid bleeds through small diameter holes or slots 33 in the walls of the tubes and optionally in the headers.The bleed gas forms a protective sheath or curtain between the outside surface of the headers and tubes and the effluent gas stream passing down through heat exchanger 16A on shell side 20. The bleed gas then mixes with the effluent gas stream, and the partially cooled gas stream leaves through outlet 21.

The heated gaseous heat transfer fluid from outlet 65 passes through line 66, inlet 67 of heat exchanger 55 and then down through shell side 59 and out through bottom outlet 60 for recirculation to heat exchanger 16A and reheating, as previously described.

In the operation of the embodiment of the process shown in Fig. 4, the stream of gaseous heat transfer fluid is heated in tubes 17 of heat exchanger 16A. Then in heat exchanger 55, the amount of sensible heat given up by the stream of heat transfer fluid continuously passing down through shell side 59 is sufficient to heat the continuous stream of up-flowing steam in tubes 58 with which it passes in noncontact indirect heat exchange to produce said superheated steam.

The superheated steam leaves through line 39 and a portion may be passed through line 40, valve 41, lines 105, 31, and mixed in line 35 with fuel from line 30. The feed mixture is then introduced into gas generator 1 by way of burner 6. The remainder of the superheated steam may be exported through line 106, valve 107, and line 108.

Optionally, a portion of the superheated steam may be used as the working fluid in steam turbine 70, in the manner described for the superheated steam in line 44 of Fig. 3.

The saturated or unsaturated steam in line 48 is produced in gas cooler 23. Additional steam from elsewhere in the system may be introduced through line 95, valve 96 and line 97. At least a portion of the effluent gas stream leaving gas cooler 23 i.e. 1-100 vol. % may be introduced into gas cleaning and optional purification zone 91. Optionally, a portion of the gas stream may by-pass cleaning or cleaning and purification zones 91 by way of line 124, valve 125, and line 126. Clean and optionally purified product gas is produced in 91 and at least a portion is recycled as make-up gas to compressor 69. The remainder of the product gas in line 121 may be used, for example, as fuel gas in the combustor of a gas turbine. The flue gas from the combustion chamber is introduced into an expansion turbine as the working fluid.The expansion turbine may be used to drive a compressor or an electric generator, as previously described. Other uses for the product gas have been described previously. At least a portion of the steam for superheater 55 is produced in waste heat boiler 23 by passing boiler feed water in line 45 through inlet 46 and shell side 25 thereby absorbing at least a portion of the sensible heat remaining in the down-flowing mixture of effluent gas stream and bleed stream in tubes 24 which leaves by outlet 26 and line 54. At least a portion of the steam produced in gas cooler 23 is introduced into superheater 55 by way of outlet 47, lines 98, 48 and flanged inlet 56. Optionally, superheated steam from line 39 or steam from line 53 may be introduced into gas generator 1 as a temperature moderator and as a transport medium for the hydrocarbonaceous fuel.

Alternatively, the effluent gas stream from gas generator 1 may be passed through the tubes in heat exchangers 16 and 23 connected in series. In such case, the gaseous heat transfer fluid in line 63 will pass through the shell side of heat exchanger 16A. A portion of the heat transfer fluid will then bleed through the walls of the tubes and header and then into the effluent gas stream flowing down through the tubes. However, first a protective sheath of gaseous heat transfer fluid is formed on the inside sur faces of the tubes and both of the headers.

Optionally, only the upstream header may be equipped with bleed holes.

The cooled effluent gas stream leaving through line 54 is passed through line 117, valve 118, line 119, and into a cleaning and optional purification operation as shown as 91 in the drawing.

The cleaned and optionally purified gas leaves through lines 120 and 121, valve 122, and line 123. When the product gas in line 123 is fuel gas, a portion may be burned in a gas furnace to produce heat. Alter natively, a portion may be introduced into the combustor of a gas turbine (not shown).

The combustion gases pass through an ex pansion turbine for the product of mech anical energy. The product gas may also comprise synthesis gas, reducing gas, or pure hydrogen. At least a portion of the effluent gas stream plus bleed gas in line 54 may by-pass cleaning and purification zones 91 by way of line 124, valve 125, and line 126.

A portion of the product gas in line 120 is used as make up-to replace the gaseous heat transfer fluid bled through the open ings in tubes 17 and headers 13 and 14 of heat exchanger 16. This make-up gas stream is cooler than the gaseous heat transfer fluid in line 61 and is passed through line 130, valve 131, line 115, and compressed in compressor 69 to above the pressure of the effluent gas stream on shell side 20 of heat exchanger 16A. As previously described, the compressed make-up gas is mixed with the gaseous heat transfer fluid from line 61 and the mixture is circulated in the loop between heat exchangers 1 6A and 55.

The following Examples illustrate embodimetns of the process of this invention. The processes are carried out continuously and the quantities specified are on an hourly basis for all streams of materials. The volumes are expressed at OOC and 1 atmosphere pressure. Pressures are absolute pressures. EXAMPLE 1 EXAMPLE 1 The embodiment of the invention represented by Example 1 is depicted in Fig. 1 of the drawings as previously described. 89896 cubic metres of raw synthesis gas are continuously produced in a free-flow noncatalytic gas geneartor by partial oxidation of a hydrocarbonaceous fuel (to be further described) with oxygen (about 99.7 volume % purity).The hydrocarbonaceous fuel is a pumpable slurry comprising 470.3 Kg. of particulate carbon recovered later by cleaning the raw synthesis gas product and 26014 Kg. of reduced crude oil having the following ultimate analysis in Wt. %: C 85.87, H2 it.10, S 2.06, N2 0.78, O2 0.16, and ash 0.04. Further the reduced crude oil has an API gravity of 12.5 (specific gravity 0.983), a heat of combustion of 101 85 cal./ g. and a viscosity of 479 Saybolt Seconds Furol at 500 C. (1170 centistokes).

About 13007 Kg. of superheated steam produced subsequently in the process at a temperature of 399"C. and a pressure of about 40.8 atmospheres are mixed with said reduced crude oil to produce a feed mixture having a temperature of about 295"C. with is continuously introduced into the annulus passage of an annular-type burner and which discharges into the reaction zone of said gas generator. About 19937 cubic metres of oxygen at a temperature of about 260"C. are continuously passed through the centre passage of said burner and mixed with the dispersion of superheated steam and crude oil.

Partial oxidation and related reactions take place in the free-flow reaction zone of the gas generator to produce a continuous effluent stream of raw synthesis gas at a temperature of 1305"C. and a pressure of 28.2 atmospheres. The effluent steam of hot raw synthesis gas from the gas generator passes through a separate heat exchanger or superheater where it is cooled to a temperature of 1125"C. by heat exchange with a continuous stream of saturated steam produced subsequently in the process.

65738 Kg. of saturated steam enter the superheater at a temperature of 253"C. and a pressure of 41.5 atmospheres. About 65738 Kg. of superheated steam leave the superheater at a temperature of 400"C. and a pressure of 40.8 atmospheres. As previously described, a portion of this continuous stream of superheated steam is introduced into the gas generator, preferably in admixture with the crude oil. Optionally, a portion of the superheated steam is used as the working fluid in a turbocompressor for example in an air separation plant for producing the free-oxygen feed to the gas generator.

The partially cooled stream of raw synthesis gas leaving the superheater is then passed through the tubes of a separate conventional gas cooler and cooled to a temperature of about 270"C. by heat exchange with 65738 Kg. of boiler feed water supplied in a continuous stream on the shell side. A stream of about 65738 Kg. of said by-product saturated steam is thereby produced at a temperature of about 253"C.

and a pressure of about 41.5 atmospheres.

As previously described, at least a portion of this saturated steam is passed into the superheater for conversion into superheated steam. The remainder of the saturated steam may be used elsewhere in the process, for example to preheat the free-oxygen containing gas.

The continuous effluent stream of raw synthesis gas leaving the gas cooler after heat exchange with the boiler feed water has a pressure which is substantially the same as that in the reaction zone of the gas generator, less ordinary pressure drop in the lines and heat exchangers. This pressure drop may be less than about 1.35 atmospheres. The composition of the stream of raw synthesis gas leaving the gas cooler is as follows: H2 41.55%, CO 41.59%, CO2 4.61%, H20 11.46%, H2S 0.40%, COS 0.02%, CH4 0.13%, N2 0.21%, and Ar 0.03%. About 474.5 Kg. of uncovered particulate carbon are entrained in the effluent stream of raw synthesis gas. Particulate carbon and other gaseous impurities may be removed from the raw synthesis gas in downstream gas cleaning and purifying zones. Optionally, a portion of said superheated steam may be mixed with the synthesis gas stream and then subjected to water-gas shift to convert carbon monoxide in the gas stream into hydrogen and carbondioxide. The CO2 may be then removed to produce a gas stream comprising hydrogen.

EXAMPLE 2 The embodiment of the invention represented by Example 2 is depicted in Fig. 2 of the drawing, as previously described.

The type and amounts of materials fed to the free-flow noncatalytic gas generator in Example 2 are substantially the same as those previously described for Example I.

Similarly, the composition and amount of raw synthesis gas, and the amounts of saturated steam and superheated steam produced are substantially the same in Examples 1 and 2. Further, the operating temperature and pressures in the gas generator and related heat exchangers, and for the related streams of materials and products are substantially the same in both examples.

In Example 2, 9361 Kg. of hydrogen are cycled continuously between heat exchanger 16, and separate superheater 55 as the heat transfer fluid.

The continuous effluent stream of raw synthesis gas from the gas generator at a temperature of 1305"C. and a pressure of 28.2 atmospheres is reduced to a temperature of 1124"C. by heat exchange with said heat transfer fluid which enters separate heat exchanger 16 at a temperature of 455"C. and leaves at a temperature of 805"C. The temperature of the continuous stream of raw synthesis gas is then reduced further to 271 or. by heat exchange with boiler feed water in gas cooler 23. A continuous stream of saturated steam produced in gas cooler 23 at a temperature of 252"C.

is then converted into a continuous stream of superheated steam at a temperature of 400"C. and a pressure of 40.8 atmospheres in separate superheater 55 by noncontact heat exchange with said heat transfer fluid which enters superheater 55 at a temperature of 805"C. and leaves at a temperature of 455"C.

EXAMPLE 3 The embodiment of the invention represented by Example 3 is depicted in Fig. 3 of the drawing as previously described.

The type and amounts of materials fed to the gas generator are substantially the same as those described in Example 1.

Similarly, the composition and amount of raw synthesis gas are also substantially the same as in Example 1. The effluent stream of hot raw synthesis gas from the gas generator passes through the tubes of separate shell and tube heat exchanger or superheater 1 6A where it is cooled to a temperature of 1125"C. by heat exchange with a continuous stream of saturated steam produced subsequently in the process. 65738 Kg. of saturated steam enter the shell side of the superheater at a temperature of 253"C. and a pressure of 41.5 atmospheres.

About 90 vol. % of the saturated steam leave the heat exchanger as superheated steam at a temperature of 400"C. and a pressure of 40.8 atmospheres. As described in Example 1, a portion of this continuous stream of superheated steam is introduced into the gas generator, preferably in admixture with the crude oil. Optionally, a por- tion of the superheated steam is used as the working fluid in a turbocompressor for example in an air separation plant for producing the free-oxygen feed to the gas generator. The remainder of the saturated steam i.e. about 6573 Kg. that is introduced into the superheater bleeds through small diameter holes in the tubes and upstream header and mixes with the hot raw synthesis gas passing therethrough.A sheath of steam lines the inside surface of the tubes, thereby protecting the tubes from corrosive attack by the raw synthesis gas.

Further, no carbon or ash deposits out on the inside surface of the tubes.

The partially cooled stream of raw synthesis gas in admixture with bleed steam leaving the superheater is then passed through the tubes of a separate conventional gas cooler and cooled to a temperature of about 271"C. by heat exchange with 65738 Kg. of boiler feed water supplied in a continuous stream on the shell side. A stream of about 65738 Kg. of said byproduct saturated steam is thereby produced at a temperature of about 253"C and a pressure of about 41.5 atmospheres. As previously described, this saturated steam is passed into the superheater 16A for conversion into superheated steam.

The continuous effluent stream of raw synthesis gas leaving the gas cooler after heat exchange with the boiler feed water has a pressure which is substantially the same as that in the reaction zone of the gas generator, less ordinary pressure drop in the lines and heat exchangers. This pressure drop may be less than about 1.35 atmospheres. The composition of the stream of raw synthesis gas leaving the gas cooler is as follows (mole % dry basis) H2 46.95, CO 46.99, CO2 5.19, H2S 0.45, COS 0.02, CH4 0.14, N2 0.23, and Ar 0.03. About 474.5 Kg. of unconverted particulate carbon are entrained in the effluent stream of raw synthesis gas. Particulate carbon and other gaseous impurities may be removed from the raw synthesis gas in downstream gas cleaning and purifying zones.Optionally, a portion of said superheated steam may be mixed with the synthesis gas stream and then subjected to water-gas shift to convert carbon monoxide in the gas stream to hydrogen and carbon dioxide. The CO2 may be then removed to produce a gas stream comprising hydrogen.

EXAMPLE 4 The embodiment of the invention represented by Example 4 is depicted in Fig. 4 the i'thie draw as previorusly described.

The type and amounts of materials fed to tte free4oiw toncatalytic gas generator i Example 4 ar ubstantially the same as sst!hoSé pAvioudy described for Example 1.

Similarly tW'e composition and amount of 'w synthesis gas, and 'the amounts of satured steaSì and superheated steam pro 'aie stbstantiafly the same -as in Ex lt l. Further, the operating tempera ture and pressures in the gas generator' and related hëa't ièxchingErs, and 'for the related 'ea'fiis 'of materials and products 'are substantiblly the same in both examples.

!h Example 4, 9361 Kg. of hydrogen as produced downstream in the process are cycled continuously between heat exchanger 16A ana separate superheater 55 as the heat tranfer fluid.

The continuous effluent stream of raw synthesis gas from the gas generator at a temperature of 1305 C and a pressure of 28.2 atmdspheres is reduced to a tempera ture of 1125"C. by heat exchange with said heat transfer fluid which enters separate heat exchanger 16A at a temperature of 455 C.

and leaves at a temperature of 805 C. The temperature of the continuous stream of raw synthesis gas in admixture with bleed hydrogen is then reduced further by heat exchange with boiler feed water in gas cooler 23. A continuous stream of saturated steam produced in gas cooler 23 at a tem perature of 253"C. is then converted into a continuous stream of superheated steam at a temperature of 400"C. and a pressure of 40.8 atmosphere in separate superheater 55 by non contact heat exchange with said heat transfer fluid in admixture with make up hydrogen which enters superheater 55 at a temperature of 805 C.

WHAT WE CLAIM IS:- 1. A process for producing gaseous mix tures comprising H2 and CO by the partial oxidation of a fuel, containing carbon and hydrogen with a free-oxygen containing gas, at a temperature from 815 to 19300C and a pressure about 1 to 250 atmospheres ab solute in the reaction zone of a free-flow noncatalytic gas generator, which comprises removing sensible heat from an unquenched effluent gas stream from the generator by passing it in sequence through first and second heat exchange zones, the sensible heat removed in said second zone being employed to convert a stream of water into steam by indirect heat exchange, and the sensible heat removed in said first zone being used to convert at least a portion of said steam into superheated steam.

2. A process as claimed in claim 1 wherein said steam is passed from said second zone into said first zone and is superheated in said first zone.

3. A process as claimed in claim 2 wherein said first zone comprises a shell and tube heat exchanger and a portion of said steam is continuously bled into the effluent gas stream through openings in the walls of said heat exchanger.

4. A process as claimed in claim 1 wherein said steam is passed from said second zone into a third heat exchange zone in which it is superheated by indirect heat exchange with a stream of gaseous heat transfer fluid which is cycled between said first and third zones to transfer sensible heat from said first zone to said third zone.

5. A process as claimed in claim 4 wherein said first zone comprises a shell and tube heat exchanger and a bleed stream portion of said heat transfer fluid is continuously bled into the effluent gas stream through openings in the walls of said heat exchanger.

6. A process as claimed in claim 5 wherein the mixture of effluent gas and said bleedstream portion of gaseous heat transfer fluid is clean effluent product gas stream is mixed with cooled gaseous heat transfer fluid leaving said third heat exchange zone and the resulting gas mixture is introduced into the first heat exchange zone as said gaseous heat transfer fluid at a higher pressure than said hot effluent gas stream.

7. A process as claimed in claim 4 wherein said heat transfer fluid is H2O, helium, nitrogen, argon hydrogen, or a mixture of H2+CO.

8. A process as claimed in claim 4 or 5 wherein the heat transfer fluid is hydrogen obtained from effluent product gas, after said heat exchange, by cleaning, water-gas shift, and purifying.

9. A process as claimed in claim 4 wherein said heat transfer fluid is sodium, potassium, mercury, or sulphur.

10. A process as claimed in claim 4 wherein said heat transfer fluid leaves said first heat exchange zone as a vapor, and said vapor is condensed into a liquid in said third heat exchange zone, and said liquid heat exchange fluid is recycled to said first heat exchange zone.

11. A process as claimed in any preceding claim wherein the stream of steam has a temperature from 150 to 375 C. and a pressure from 4 to 260 atmospheres absolute and is converted into superheated steam at a temperature from 400 to 6000 C.

and a pressure from 4 to 260 atmospheres absolute.

12. A process as claimed in any preceding claim wherein at least a portion of the superheated steam is introduced as the working fluid into a steam turbine for producing mechanical work or electrical energy.

13. A process as claimed in any preceding claim wherein at least a portion of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the i'thie draw as previorusly described. The type and amounts of materials fed to tte free4oiw toncatalytic gas generator i Example 4 ar ubstantially the same as sst!hoSé pAvioudy described for Example 1. Similarly tW'e composition and amount of 'w synthesis gas, and 'the amounts of satured steaSì and superheated steam pro 'aie stbstantiafly the same -as in Ex lt l. Further, the operating tempera ture and pressures in the gas generator' and related hëa't ièxchingErs, and 'for the related 'ea'fiis 'of materials and products 'are substantiblly the same in both examples. !h Example 4, 9361 Kg. of hydrogen as produced downstream in the process are cycled continuously between heat exchanger 16A ana separate superheater 55 as the heat tranfer fluid. The continuous effluent stream of raw synthesis gas from the gas generator at a temperature of 1305 C and a pressure of 28.2 atmdspheres is reduced to a tempera ture of 1125"C. by heat exchange with said heat transfer fluid which enters separate heat exchanger 16A at a temperature of 455 C. and leaves at a temperature of 805 C. The temperature of the continuous stream of raw synthesis gas in admixture with bleed hydrogen is then reduced further by heat exchange with boiler feed water in gas cooler 23. A continuous stream of saturated steam produced in gas cooler 23 at a tem perature of 253"C. is then converted into a continuous stream of superheated steam at a temperature of 400"C. and a pressure of 40.8 atmosphere in separate superheater 55 by non contact heat exchange with said heat transfer fluid in admixture with make up hydrogen which enters superheater 55 at a temperature of 805 C. WHAT WE CLAIM IS:-

1. A process for producing gaseous mix tures comprising H2 and CO by the partial oxidation of a fuel, containing carbon and hydrogen with a free-oxygen containing gas, at a temperature from 815 to 19300C and a pressure about 1 to 250 atmospheres ab solute in the reaction zone of a free-flow noncatalytic gas generator, which comprises removing sensible heat from an unquenched effluent gas stream from the generator by passing it in sequence through first and second heat exchange zones, the sensible heat removed in said second zone being employed to convert a stream of water into steam by indirect heat exchange, and the sensible heat removed in said first zone being used to convert at least a portion of said steam into superheated steam.

and a pressure from 4 to 260 atmospheres absolute.

13. A process as claimed in any preceding claim wherein at least a portion of

the superheated steam is introduced into the reaction zone of said gas generator.

14. A process as claimed in claim 13 wherein said superheated steam is a carrier for said fuel feed to the gas generator.

15. A process as claimed in any preceding claim wherein at least a portion of the superheated steam is used as the working fluid in a steam turbine used to compress air feed to an air separation unit thereby producing oxygen having a purity of 95 mole % or more for reacting in said gas generator.

16. A process as claimed in any preceding claim wherein at least a portion of particulate carbon, ash, slag, scale, refractory, and mixtures thereof entrained in the effluent gas stream is removed from said gas stream before it flows into said first heat exchange zone.

17. A process as claimed in any preceding claim wherein the fuel is preheated to a temperature up to about 430"C. but below its cracking temperature with at least a portion of the superheated steam before said fuel is introduced into the gas generator.

18. A process as claimed in any preceding claim wherein at least a portion of the clean and optionally purified gas stream is introduced into the combustor of a gas turbine, and the gaseous products of combustion from said combustor are introduced into an expansion turbine for producing power. A

19. A process for producing gaseous mixtures comprising H2 and CO by the partial oxidation of a fuel as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.