Exxon Research and Engineering Company

The United States of America As Represented by the Administrator of the

The United States of America As Represented by the Administrator

The United States of America As Represented by the Administrator of

Gerald Moss

John William Craig

James Howard Taylor

David Lyon

Graham Lloyd Johnes

The apparatus comprises a process vessel, containing a process bed of fluidized particles, having a first submerged port at a first end and a second submerged port at a second end. Both ports are inclined in the same sense so that particles leave the second end of the bed at a higher level than they enter the first end. Fluidized bed material entering the second port becomes defluidized and slides down the port, optionally with the assistance of a fluid injected into the port. The first port conducts particles into the process bed from a second fluidized bed and the second port conducts particles out of the process bed (e.g. into the second bed). The process bed rests on a fluid distributor having a horizontal first part adjoining, and no higher than the level of, the lower end of the first port and a horizontal second part adjoining, and at the level of, the second port, there being a vertical step connecting the first and second distributor parts at a location between the first and second ports. In operation, particles at the bottom layers of the process bed are transferred relatively rapidly from the first port to the second port, while particles at higher levels in the bed have relatively prolonged residence times in the bed.

Apparatus for use in processing a substance in a fluidized bed

A sulfur-containing fuel is passed into a first fluidized bed (13) containing CaSO.sub.4 and CaO and an oxygen-transfer mediator (e.g. H.sub.2) whereby the fuel is converted to combustible gas (18), some CaSO.sub.4 being reduced to CaS and sulfur being fixed as CaS by reaction with CaO. Bed particles pass from the bottom layer of the first bed (13) into the bottom layer of the second bed (14) which is fluidized by air at conditions such that some, but not all of the CaS is selectively oxidized to CaSO.sub.4 with no liberation of sulfur moieties. Bed particles pass from the bottom layer of the second bed (14) to the bottom layer of a third bed (15) optionally after passage via a fourth bed (60, FIG. 2) between the second and third beds. In the third bed (15), particles are fluidized with air to convert CaS selectively to CaSO.sub.4 with no liberation of sulfur moiety whereby to raise the particles' temperature sufficiently above that of the first bed that particles passing from the bottom layer of the third bed into the bottom layer of the first bed provide sufficient sensible heat to maintain the fuel conversion temperature of the first bed (13). In the fourth bed (60, FIG. 2), particles are fluidized with air under such conditions that sulfur moiety is liberated, preferably at a rate which approximately equals the rate of sulfur-capture in the first bed (13) whereby to maintain approximately a constant amount of reactive CaO in the beds for sulfur-capture in the first bed (13).

Converting a fuel to combustible gas

Apparatus for converting a fuel to combustible gas

Apparatus for carrying out a combined absorption and adsorption process comprising an adsorber (1) housing adsorbent (30) (e.g. 13.times. zeolite molecular sieve) and having means (2) for supplying heat to the adsorbent (30) from an external source, a vapor outlet in said adsorber connected by conduit (31) to a heat exchanger (4) capable of supplying heat to the working fluid of the generator (5) of an absorber system, means (19) for transferring heat to the generator (5) from the external source of heat, an expansion valve (6) connected by conduit (32) to said heat exchanger (4), an evaporator (7) connected by conduit (32) to said expansion valve (6) and also connected by conduit (35) to the adsorber (1), said absorber system comprising said generator (5) connected by conduit (8) to a condenser (9), an expansion valve (11) connected by conduit (40) to said condenser (9), an evaporator (7) connected by conduit to said expansion valve (11) and an absorber (13) connected by conduit (34) to said evaporator (7) and connected by two separate conduits (41, 42) to the generator (5), one conduit (42) having an expansion valve (15) therein.

Combined staged air conditioner and heat store

A low pollution method of burning a fuel comprises gasifying the fuel in a gasifier bed containing particles which are fluidized by a fluidizing gas containing substantially no inert components. The resulting combustible gas is burned with air diluted with nitrogen to reduce NO.sub.x formation. In addition, NO.sub.x production from the nitrogen content of the fuel is reduced as a result of the gasification of the fuel to combustible gas before combustion with air. Preferably the gasifier bed contains CaO to fix sulfur from the fuel as CaS. In one embodiment, the gasifier bed (51) contains CaSO.sub.4 and the fluidizing gas contains H.sub.2, inter alia, which mediates the transfer to the fuel of chemically-bound oxygen from the CaSO.sub.4 (which is thereby reduced to CaS). Particles containing CaS are passed to an oxidizer bed (72) wherein they are fluidized by air. The CaS is exothermically oxidized to CaSO.sub.4 by extracting oxygen from the air which is thereby heated and substantially exhausted of oxygen. The hot CaSO.sub.4 is transferred from the oxidizer bed (72) to the gasifier bed (51) for gasifying further amounts of fuel, and the hot oxygen-depleted air is cooled by heat exchange (in 80) with boiler feed water, and then added to combustion air (in 69) to reduce the peak flame temperature when the combustible gas is burned at the burner (56) thereby mitigating NO.sub.x production from reactions in the flame between oxygen and nitrogen from the atmosphere. Because the fuel is gasified in the absence of diluents, the gasifier bed (51), combustible gas conduit (55), the burner (56) and gas circulation fans are of reduced sizes. The low pollution combustion of the fuel necessitates no modification of the furnace or boiler (84) and results in no increase in its operating costs or reduction in efficiency.

Low pollution method of burning fuels

Fuel is passed (via line 13) to a fluidized fuel conversion bed (21) containing reactive CaO and CaSO.sub.4 at a fuel-oxidation temperature (e.g. 730.degree. C.) below the temperature at which CaO reacts with CO.sub.2 to form CaCO.sub.3. The bed is fluidized by an inerts-free gas containing hydrogen (and/or a source thereof, e.g. steam) and fuel is therein partially oxidized, CaSO.sub.4 being reduced to CaS. CO.sub.2 thus formed is fixed as CaCO.sub.3, and bed solids containing CaS and CaCO.sub.3 pass (via 33) to a fluidized decarbonation bed (34) operated at a temperature (e.g. 850.degree. C.) above the decarbonation temperature of CaCO.sub.3 whereby CO.sub.2 is liberated and is recovered after passage through a heat recovery device (6). The decarbonation bed (34) is preferably fluidized by the gas products from the fuel conversion which reduce CaSO.sub.4 therein to CaS and form additional CO.sub.2. Bed solids containing CaS and CaO pass (line 37) to an oxidation bed (36) fluidized with air to convert CaS to CaSO.sub.4 with much heat liberation. Hot bed solids are returned to the decarbonation and fuel conversion beds to furnish heat and CaSO.sub.4 to maintain the reactions therein.

Process for producing CO.sub.2, and CO.sub.2 so produced

Ash-contaminated solid or semi-solid fuel is passed into the bottom zone of a fluidized bed gasifier, preferably containing CaO to fix labile sulfur moieties, and gasified at a temperature below the ash-softening point. The resulting char and ash of relatively low size and/or weight pass to a top zone of the bed wherein the char is gasified at a temperature above the ash-softening point whereby a substantial proportion of the ash sticks to and agglomerates with solids in the top zone until the particle size and/or weight of the resulting agglomerates causes them to sink to the bottom of the gasifier from where they can be recovered. The hot gases leaving the top of the gasifying bed have a reduced burden of entrained ash, and may be cooled to prevent any entrained ash adhering to downstream equipment through which the gases pass.

Gasification of ash-containing solid fuels

The invention relates to the conversion of fuel (solid and/or liquid) to reducing and/or synthesis gas by contacting the fuel in a fluidized conversion bed (13) with a solid oxygen donor (e.g. CaSO.sub.4) at a fuel conversion temperature (e.g. 850.degree. to 1150.degree. C.) in the presence of at least one gas/vapor phase substance such as H.sub.2 and/or H.sub.2 O and/or CO and/or CO.sub.2 which serves to promote and or mediate the transfer of oxygen from the donor to the fuel and preferably in the absence of non-reactive gases (e.g. N.sub.2) whereby the fuel is converted to a reducing and/or synthesis gas product by (inter alia) partial oxidation employing the oxygen of the solid oxygen donor, the latter being reduced (e.g. CaS). The reduced donor is exothermically oxidized in a fluidized oxidation bed (35) by contact with an oxygen-containing gas (e.g. air) and re-used for converting further quantities of fuel. Moieties (e.g. sulfur/sulfur compounds) whose presence is undesirable in the gas product may be removed by a solid moiety-fixing agent (e.g. CaO) in the conversion bed (13). The moiety-fixing properties of the latter are at least partly regenerated in a fluidized regenerator bed (48) by treatment in a suitable regenerating atmosphere, and the regenerated moiety-fixing agent is returned to the conversion bed (13) directly and/or indirectly via the oxidation bed (35).

Method of converting liquid and/or solid fuel to a substantially

A selected fraction of solid particles having sizes, densities and/or weights in a selected range is separated from a mixture of articles by fluidizing the mixture in a bed using a fluidizing fluid to cause particles including the selected fraction to pass out of the top of the bed; conveying the particles in a conveying fluid to a suitable separator (e.g. a cyclone) wherein the selected particles fraction is separated from smaller, lighter particles; injecting the separated fraction from the separator into a utilization zone (e.g. a fluid bed reactor); entraining other particles in the conveying fluid to another separator (e.g. a cyclone) to produce solids-free conveying fluid which is recirculated for re-use. The original particles mixture may be obtained by separation (e.g. in a cylone) from fluid leaving the utilization zone.

Fluidized bed systems

A distributor for distributing a fluid into the volume of a fluidized bed contained in a vessel comprises a base member in which are mounted upstanding nozzles having outlets for directing the fluid horizontally away from the nozzles into the volume of the bed, the outlets of some nozzles being arranged at a lower level than the outlets from other nozzles so that fluidizable bed material will be fluidized above a contour substantially defined between the outlets of the nozzles. Thus, there will be a 'well' or depression in the countour around each nozzle, and the countour will extend to just below the outlet of each nozzle. The contour may be formed by the upper surface of unfluidized fluidizable material (e.g., from the bed) or by the upper surface of non-fluidizable material (e.g. blocks of refractory cement or metal sheeting) which may constitute at least part of the base member. Another fluid may be passed into the volume of the fluidized bed by providing conduits which extend horizontally beneath the countour (e.g. for protection from the fluidized bed) except for one end which extends into the volume of the wells or depressions. The other end is preferably outside the distributor and the conduits are preferably straight and withdrawable from the distributor.

Distributing fluids into fluidized beds

Sulfur-containing fuels are converted to substantially sulfur-free combustible gas in an integrated process involving part combustion in a dense phase fluidized conversion bed of particles comprising alkaline earth metal oxides. An oxygen-containing gas is passed into the base of the bed to maintain a relatively high fuel/air ratio. Sulfur is chemically fixed in the particles by reaction to form alkaline earth metal sulfide. Particles containing alkaline earth metal sulfide are circulated from one region of the conversion bed to one region of a dense phase fluidized regeneration bed operated at a higher temperature and fluidized by passing into the base thereof an oxygen-containing gas which exothermically regenerates chemically active alkaline earth metal oxide from the sulfide liberating gases which have a low oxygen content and a relatively high content of sulfur moieties (e.g. SO.sub.2). Hot particles are circulated from a second region of the regeneration bed to a second region of the conversion bed for use in fixing further quantities of sulfur from sulfur-containing fuel. Both beds contain a high molar proportion of unreacted alkaline earth metal oxide thereby imparting high sulfur-retaining capability to the conversion bed, and the beds interact cooperatively with each other at least in that particles entering the regeneration bed moderate temperatures therein and particles entering the conversion bed add heat thereto thereby reducing the fuel requirement for maintaining the conversion bed temperature.

Integrated process for converting sulfur-containing fuels to low sulfur

Fines are removed from a fines-containing fluid by fluidizing a bed of fluidizable solids with the fines-containing fluid at conditions avoiding fluid spouting at the bed surface, the bed solids being preferably at least two orders of magnitude greater in size than the particles, and being coated with a substance whose stickiness changes during its residence time in the bed. Particles adhere to the transiently sticky solids and can be recovered for re-use. Useful for cleaning dusty gases and recovering catalyst from cracker flue gas.

Removing particles from a particle-containing fluid

CaS is converted to CaO with increased production of SO.sub.2 and decreased production of CaSO.sub.4 by passing CaS-containing particles into one region of a conversion bed wherein they are fluidized at an elevated temperature by an upwardly-passing oxygen-containing fluidizing gas, removing particles of increased CaO content from a second region of the bed, and providing a reducing agent (e.g. a hydrocarbon gas, liquid or carbonaceous solid) in the bed between the first and second regions, preferably nearer the latter, to produce a mildly reducing atmosphere which reduces any CaSO.sub.4 and increases the yield of SO.sub.2. The removed particles may be circulated to a fluidized gasification bed wherein a sulphur-containing fuel is converted to substantially sulphur-free fuel gas and wherein the sulphur is fixed as CaS in the particles, which particles are thereafter recirculated to the conversion bed.

Converting calcium sulphide to calcium oxide

Solid particles comprising combustible matter (e.g. coal) associated with or contaminated by inert matter (e.g. ash, rock) is segregated in a segregation zone into low density/small size and high density/large size fractions. The low density/small size fractions are passed to a utilization zone for conversion of the combustible matter. The high density/large size fractions are size reduced (e.g. by grinding) and either returned to the segregation zone, or passed at least in part, directly to the utilization zone. The conversion of the combustion matter proceeds more efficiently as a result. The segregation zone may operate by fluidized size/density segregation and in the utilization zone, the combustible matter may be at least partially combusted, preferably in a fluidized bed.

Utilization of solid material containing combustible matter

The invention comprises a fluid distributor which, in a preferred embodiment, comprises an array of parallel rollers rotatably mounted at their ends. All, or alternate, rollers have a number of peripheral grooves or slots which define, with adjacent rollers, apertures for the passage of fluid through the distributor. Suitable deposit-removing means (e.g. in the form of chisel-blades) are mounted either on rollers or separate support members so as to be opposite respective grooves or slots in the rollers and to be receivable in the grooves or slots, so that on relative movement of the grooved or slotted rollers and the deposit-removing means, the latter remove deposited material from the grooves or slots. The invention is useful in passing deposit-forming fluids (e.g. tarry or dusty gases) into fluidized beds supported on the distributor.

Growing community of inventors

Wantage, United Kingdom

Gerald Moss