Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B49/00—Destructive distillation of solid carbonaceous materials by direct heating with heat-carrying agents including the partial combustion of the solid material to be treated
  • C10B49/02—Destructive distillation of solid carbonaceous materials by direct heating with heat-carrying agents including the partial combustion of the solid material to be treated with hot gases or vapours, e.g. hot gases obtained by partial combustion of the charge
  • C10B49/04—Destructive distillation of solid carbonaceous materials by direct heating with heat-carrying agents including the partial combustion of the solid material to be treated with hot gases or vapours, e.g. hot gases obtained by partial combustion of the charge while moving the solid material to be treated
  • C10B49/06—Destructive distillation of solid carbonaceous materials by direct heating with heat-carrying agents including the partial combustion of the solid material to be treated with hot gases or vapours, e.g. hot gases obtained by partial combustion of the charge while moving the solid material to be treated according to the moving bed type
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
  • C10B53/02—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of cellulose-containing material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/02—Fixed-bed gasification of lump fuel
  • C10J3/06—Continuous processes
  • C10J3/14—Continuous processes using gaseous heat-carriers
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/02—Fixed-bed gasification of lump fuel
  • C10J3/06—Continuous processes
  • C10J3/16—Continuous processes simultaneously reacting oxygen and water with the carbonaceous material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/02—Fixed-bed gasification of lump fuel
  • C10J3/20—Apparatus; Plants
  • C10J3/34—Grates; Mechanical ash-removing devices
  • C10J3/36—Fixed grates
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/46—Gasification of granular or pulverulent flues in suspension
  • C10J3/48—Apparatus; Plants
  • C10J3/485—Entrained flow gasifiers
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/72—Other features
  • C10J3/721—Multistage gasification, e.g. plural parallel or serial gasification stages
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2200/00—Details of gasification apparatus
  • C10J2200/09—Mechanical details of gasifiers not otherwise provided for, e.g. sealing means
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2200/00—Details of gasification apparatus
  • C10J2200/15—Details of feeding means
  • C10J2200/152—Nozzles or lances for introducing gas, liquids or suspensions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0903—Feed preparation
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/0916—Biomass
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/0916—Biomass
  • C10J2300/092—Wood, cellulose
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/094—Char
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/0946—Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0956—Air or oxygen enriched air
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0973—Water
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1625—Integration of gasification processes with another plant or parts within the plant with solids treatment
  • C10J2300/1637—Char combustion
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/10—Process efficiency
  • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/141—Feedstock
  • Y02P20/145—Feedstock the feedstock being materials of biological origin

Definitions

• the present invention generally relates to a two-stage high-temperature steam gasifier for producing synthesis gas and, optionally, activated carbon, from a coarse carbonaceous feedstock, and more particularly to a gasifier capable of simultaneously gasifying a coarse solid carbonaceous feedstock and a fine solid carbonaceous feedstock or a liquid carbonaceous feedstock.
• the present invention also relates to a process of gasifying a coarse carbonaceous feedstock using a two-stage gasifier having two reactors in order to produce synthesis gas, optionally together with activated carbon, wherein no oxygen is fed to the first stage reactor, but only preheated steam having a temperature of at least 700 0 C.
• Gasification is a high-temperature thermal decomposition process of converting a solid feedstock, such as solid coal, petroleum coke, biomass, and/or solid waste, a liquid feedstock, such as black liquid oil, or a gaseous feedstock, into a fuel gas, consisting primarily of hydrogen (H 2 ) and carbon monoxide (CO), with lesser amounts of carbon dioxide (CO 2 ), water (H 2 O), methane (CH 4 ), higher hydrocarbons, and nitrogen (N 2 ) using reactants such as air, steam, and oxygen, either alone or in any combination thereof.
• a solid feedstock such as solid coal, petroleum coke, biomass, and/or solid waste
• a liquid feedstock such as black liquid oil, or a gaseous feedstock
• a fuel gas consisting primarily of hydrogen (H 2 ) and carbon monoxide (CO), with lesser amounts of carbon dioxide (CO 2 ), water (H 2 O), methane (CH 4 ), higher hydrocarbons, and nitrogen (N 2 ) using reactants such as
• the thermal gasification processes are highly endothermic chemical reactions.
• the general methods for supplying heat for the gasification use either of the following: a) an external source, e.g. sensible heat from hot char recirculation, and/or sensible heat from a heated gasification agent, b) reaction heat from oxidization of a part of the feedstock (incoming carbonaceous materials), and c) exothermal reaction heat from a non-carbonaceous material such as calcined lime and CO 2 .
• US 2004/0060236 Al teaches an economic small scale gasification system for gasifying solid fuel into pyrolysis gas, wherein heated mixed gas of steam and air is introduced into a reformer along with the pyrolysis gas producing reformed high temperature crude gas.
• the mixed gas of air and steam is preferably heated to at least 300 0 C, and more preferably at least 400 0 C. Any type of heat exchanger or heater may be employed as the air/steam heating device for heating the mixed gas of air and steam.
• US 6,837,910 teaches an apparatus and method for gasifying liquid or solid fuel, wherein a heated mixed gas of steam and air is introduced into at least one of the thermal decomposition area of the solid or liquid fuel and the reforming area of the thermal decomposed gas.
• the mixed gas of air and steam is heated to a temperature of at least 700 0 C, and more preferably higher than 800 0 C.
• a char free hydrogen rich gas where the process is performed with only steam at a temperature of 1000 0 C and at a conventional pressure of about 1 atm has been proposed by Ponzio Anna, Yang Weihong, Lucas, C, Blasiak W., in Development of a Thermal Homogenous Gasiiier System using High Temperature Agent, CLEAN AIR - International Journal on Energy for a Clean Environment., Vol. 7, No. 4., 2007.
• a method for gasifying carbonaceous materials into fuel gases is disclosed. It involves the formation of an ultra- superheated steam (USS) composition substantially containing water vapor, carbon dioxide and highly reactive free radicals thereof, at a temperature of about 1316°C to about 2760 0 C.
• USS ultra- superheated steam
• the USS composition comprising a high tem- perature flame is contacted with a carbonaceous material for rapid gasification/reforming thereof.
• the USS is formed by burning s substantially ash-free fuel with "artificial air” comprising an enhanced oxygen gas and water vapour, wherein the "artificial air” is at least about 60 mole percent.
• the oxygemfuel ratio will have to be controlled so that soot is not is not formed.
• the use of enhanced oxygen gas in the method will obviously increase the operation cost of the method.
• thermal conversion of biomass/waste/coal can be understood as comprising two mainly highly endothermic stages: devolatilization of volatiles, and char conversion, respectively.
• devolatilization of volatiles 90% of the volatile content in the total weight of biomass will be released instantaneously if it would be heated above 600 0 C.
• the second stage is char conversion.
• a much higher temperature is needed for the thermal conversion of char. Generally, this temperature should be higher than 1000 0 C, depending on the ash melting point.
• the Asian Institute of Technology (AIT), Thailand, modified a biomass gasifier which resulted in a fuel gas with a tar production of about 50 mg/Nm 3 , which is about 40 times less than a single-stage reactor under similar operating conditions (T.A. Milne and RJ. Evans, Biomass Gasification "Tars”: Their Nature, Formation and Conversion. NREL, Golden, CO, USA, Report No. NREL/TP-570-25357 (1998).
• This concept involves a downdraft gasifier with two levels of air intakes.
• the produced tar in the biomass pyrolysis process will pass through a high-temperature residue char bed at the bottom and will be decomposed at the elevated temperature.
• US 6,960,234 discloses a multi-faceted gasifier and related methods. It is a gasifier combing a fixed bed gasification section and an entrained flow gasification section. Activated carbon may be formed in the upper fixed bed section and in the entrained flow section.
• US 6,647,903 discloses a method and apparatus for generating and utilizing combustible gas using a gasifier comprising first and second reaction sections, wherein oxidizing gas is intro- quizled into both sections.
• the invention operates in a manner that enhances tar destruction while forming output fuel gas products H 2 and CO.
• some methane may also be formed.
• activated carbon may be generated.
• JP 6256775 discloses two-stage complete gasification of organic matter for methane synthesis, wherein in a first stage gasification process organic matter is gasified in the presence of steam and oxygen, and, in a second stage gasification process gaseous un-reacted matter and tar gas are gasified at a higher temperature than in the first stage gasification process.
• a gasifier comprising two stages is also disclosed. In order to disturb solid carbonaceous material from passing from the first stage gasification process to the second stage gasification process, the passage between the two stages may be narrowed, or a filter may be set between the two stages.
• the gasifier includes two inlets for oxygen and steam, one in the first stage, and the other in the second stage.
• the aim of secondary air/oxygen and/fuel injection in above works is increasing the tempera- ture in freeboard in order to decompose tar, and improve the steam-reform reaction.
• the injection of secondary air will not only increases the diluents contents, notably nitrogen, but will also reduce the combustible contents generated from gasification. This results in a decrease of LCV of the fuel gas produced.
• injection of secondary air makes it hard to control the composition of the produce gas.
• a novel fixed bed gasifier is proposed herein.
• Such gasifier is specified in claim 1.
• a method of gasifying a coarse carbonaceous feedstock, using a two-staged gasifier having two reactors, in order to produce synthesis gas, optionally together with activated carbon, wherein no oxygen is fed to the first stage reactor, but only preheated steam having a temperature of at least 700 0 C is also claimed and disclosed. Such method is provided for in claim 4.
• a two-stage gasifier of the prior art comprising: a first reactor provided with an inlet for a coarse carbonaceous feedstock, and a first inlet for steam; and a second reactor provided with a second inlet for steam, optionally together with air or oxygen; and an outlet for synthesis gas; wherein the first and second reactors are separated by a narrowed portion having a reduced cross-section for restricting passage from the first reactor to the second reactor of unreacted solid carbonaceous substance, wherein the first reactor is capable of being operated at a temperature of at least 600 0 C, and wherein the second reactor is capable of being operated at a higher temperature, the above object has been achieved by means of the technical features of the characterizing portion of said claim, according to which the second reactor is the lower reactor, the first reactor is the upper reactor, a grate is provided at the bottom end of the first reactor, said first inlet for steam is located adjacent to the bottom of the first re
• the present invention relates to a two-stage gasifier as set out above.
• one or more, and preferably all of the inlets for steam, air, oxygen and carbonaceous (waste) liquid and/or carbonaceous fine solid material enter into the gasifier tangentially in corresponding portions of the gasifier, which portions have an inner, circular cross-sections.
• the inlet for carbonaceous (waste) liquid and/or carbonaceous fine solid material comprises at least two inlets separated at a maximum distance from each other along the circumference of the circular cross-section.
• the present invention relates to a process of gasifying a coarse carbonaceous feedstock, using a two-stage gasifier having two reactors, a first and a second, respectively, in order to produce synthesis gas, optionally together with activated carbon.
• Such process is provided for in claim 4, and includes the following steps: (a) feeding a coarse carbonaceous feedstock to the first stage reactor of the gasifier; (b) subjecting the coarse carbonaceous feedstock to steam in the first stage reactor at an operational temperature of at least 600 0 C of the reactor, to effect gasification of the carbonaceous feedstock, in which process no oxygen is fed to the first stage reactor, but only preheated steam having a temperature of at least 700 0 C, and which process further includes a step (c), wherein any solid and/or liquid carbonaceous materials obtained from step (b) are subjected to preheated steam, optionally together with air or oxygen, in the second stage reactor operating at a temperature of at least 700 0 C to obtain any combination of the following products: activated carbon; CO;
• the process comprises a further step (d) wherein a fine solid car- bonaceous, and/or liquid carbonaceous feedstock, is/are being fed simultaneously into the second stage reactor of the gasifier. Accordingly, in this embodiment both a coarse feedstock and a fine solid and/or liquid carbonaceous feedstock may be fed simultaneously into the gasifier.
• externally generated preheated steam hav- ing a temperature of at least 700 0 C is also fed into the second stage reactor.
• internal combustion also referred to as partial combustion or oxidation
• in the gasifier can be kept to a minimum, since the required energy is provided externally. Consequently, supply of air or oxygen is not required for heat generation by internal combustion in this embodiment. Also, when air or oxygen is not being fed to the second reactor the yield of activated carbon can be maximised.
• air is fed to the second reactor (i.e. in addition to the high temperature steam).
• air is fed to the second reactor (i.e. in addition to the high temperature steam).
• Figure 1 shows a system flow diagram generally illustrating the inventive gasification process for biomass and solid waste.
• Figure 2 illustrates a cross-sectional view of an embodiment of the gasifier 21.
• Figure 3 is a plan view of the inventive gasifier showing the tangential liquid feedstock injection via inlets 19a and 19b.
• the inventive gasifier combines two reactors using externally generated preheated high temperature steam injection into the first reactor, where the heating demand for gasification is supplied by the sensible energy from the steam.
• the gasifier can produce a medium and higher LCV syngas.
• the first reactor is a fixed bed gasification section where the coarse feedstock is gasified
• the second reactor is an entrained-bed gasification section where the liquid and fine feedstock is gasified.
• Solid coarse feedstock is devolatilized in the first fixed bed reactor of the gasifier by means of high-temperature steam, and subsequently, in the second reactor subjected to a higher temperature sufficient to crack and destroy tars and oils.
• Activated carbon may be formed as co-product.
• the gasifier may be used with various solid and liquid feedstocks.
• the gasifier is capable of gasifying such different feedstocks simultaneously.
• the idea behind the present invention is that the gasifier 21 is separated into two stages: a first upper stage 3 for devolatilization of volatiles, which first stage only uses externally generated high-temperature preheated pure steam (preferably 700 0 C-IOOO 0 C), and a second lower stage 4 for char thermal conversion, using a high-temperature (preferably 700-1600 0 C, more preferably 800-1200 0 C) preheated mixture of air and steam, oxygen and steam, or steam only as shown in Figure 1.
• the reactor 3 includes a fixed bed comprising grate 8.
• the energy used for the devolatilization process is supplied both by the sensible energy of steam fed into the first reactor via inlet 7, and by the hot stream coming from the second reactor through the narrowed portion 20.
• the temperature in the first reactor is controlled at the level of at least 600 0 C by the quantity and the temperature of the steam fed into said reactor.
• any solid and/or liquid char produced in the first reactor will not be reacted with any oxidizers in said reactor. Consequently, any solid and/or liquid char will instead fall into the second reactor 4 by the action of the gravity.
• the energy used for char the conversion process is preferably supplied by the sensible energy of mixture of steam and air, and from partial oxidization of char.
• the temperature in the second reactor should be higher than that of the ash melting point, in order for the ash to form slag. Normally, for wood bio- mass the ash melting point can be 1300 0 C.
• the reactor 4 includes an entrained bed compris- ing grate 5.
• the activated carbon can be treated as a co-production from thermal conversion of carbon-based materials through this invention.
• the preparation of activated carbon involves two steps: carbonization of the raw material in absence of oxygen at high temperature (500-1000 0 C) in order to eliminate maximum amounts of oxygen and hy- drogen elements, and activation of the carbonized product at a higher temperature in the presence of oxidizing gas such as water, carbon dioxide or both.
• the activation shall be carried out under well controlled conditions in order to achieve a desired conversion.
• the feedstock is first gasified by high-temperature pure steam (at the level of at least 600 0 C) in the first reactor 3, then the carbon is preferably activated in the second reactor 4 by high-temperature steam.
• high temperature steam, and optionally air or oxygen (over 700 0 C), will be obtained mainly by use of a honeycomb regenerative heat exchanger as explained in, for example, EP 0 607 921, or in co-pending PCT/SE2009/050019, the relevant contents of which disclosures are incorporated herein by reference.
• FIG. 2 illustrates a cross-sectional view of the gasifier 21.
• Carbonaceous feedstock 1 enters at the top of the gasifier, through a feed inlet 2, and proceeds downward moving through the first reactor 3, then pass the grate 8, then enters second reactor 4, then pass the grate 5 until it becomes a molten ash at the bottom 6.
• the feedstock can include biomass, coal, municipal solid waste, or any combination thereof.
• the particle size of the coarse carbonaceous feedstock 1 is typically from 0.5 cm to 1,8 cm, and preferably from 0.5 to 1.2 cm.
• the feedstock is heated by a combination of the sensible heat carried by the high-temperature steam (over 700 0 C), and the sensible heat carried by the flue gas produced by char oxidization and gasification in the second reactor 4.
• High-temperature steam carried by pipe 7 for the feedstock gasification in the first reactor enters a narrowed portion or throat 20 through a port (ports) 11.
• the amount of high-temperature steam added at port 7, is set to keep the temperature at point 3 (first reactor) between 600-900 0 C, and preferably above 700 0 C.
• the temperature in the reactor 3 is controlled by the temperature and flowrate of injection of steam from point 7, and the temperature and quantity of surplus oxygen from reactor 4.
• the residence time of the feedstock 1 inside reactor 3 is mainly controlled by the gap of the grate 8.
• a throat 20 is provided.
• the diameter of the throat is generally smaller than that of the hearth of reactor 3.
• the inclination of the conical portion 14 should preferably be around 45- 60°.
• the diameter of the steam injection port 11 should preferably be 2-3 times smaller than that of the throat 20.
• the remaining fixed carbon has become activated carbon char and ash solids, which continue to move downward through the grate 8, then enter a throat 20, then enter into the second reactor 4, where they are oxidized and gasified by a mixture of high-temperature air (or oxygen) and steam.
• a mixture of high-temperature air (or oxygen) and steam When no air or oxygen is being fed with the steam into reactor 4, no oxidation will occur in reactor 4, but only gasification.
• the temperature of the second reactor 4 is further increased to a temperature slightly above the ash softening point of the fuel at the grate 5.
• the pipe 9 carries the preheated high-temperature steam or mixture of high- temperature air (or oxygen) and steam to the port 10, which then enters into the second throat 18.
• the ash softening point typically ranges from 1350-1400 0 C. If slag formation of the ash is to be avoided, the maximum peak temperature in the reactor 4 during operation is maintained at a temperature at least 50 0 C below the ash softening point, with 100 0 C below as the normal and thus preferred maximum condition.
• the temperature in reactor 4 is controlled by the preheating temperature, flowrate and the ratio of steam to carbon, and, when air or oxygen also is being used with the steam, the ratio of steam to oxygen of the mixture.
• the diameter of the second narrowed portion or throat 18 is generally smaller than that of the diameter of reactor 4, and preferably also smaller than that of the first narrowed portion or throat 20.
• the inclination of the conical portion 17 should preferably be around 45-60°.
• the diameter of the steam injection port 10 should preferably be 3-5 times smaller than that of the throat 18.
• the ash is dropped into bottom 6 through throat 18, and may be taken out batch- wise from the reactor.
• syngas flows out through the exit pipe 12. Since the temperature in the first reactor 3 is high enough, and also steam is present, most of the tar is destroyed and converted to syngas.
• the main chemical constituents of syngas are hydrogen, carbon monoxide, and methane, and carbon dioxide.
• the inventive design of the gasifier has the ability to advantageously control the ratio of hydrogen to carbon monoxide in the syngas, since the gasifier enables control within wide ranges of steam to oxygen ratio within the gasifier.
• the second reactor 4 by controlling the temperature in the second reactor 4 at 700 0 C, i.e. the same temperature as first reactor 3, and by only feeding steam to the second reactor, all tars and oils are consumed by the high-temperature steam.
• This mode of operation is very effective for generating activated carbon, and will also improve the quality of the activated carbon obtained. If gasification is to be maximized, on the other hand, the second reactor should be operated at a higher temperature than the first reactor.
• the invention can consequently also be used to produce activated carbon.
• activated carbon is created within the gasifier.
• first one only the first reactor is used, i.e. only high-temperature steam is injected through pipe 7.
• the high- temperature mixture of steam and air from pipe 9 is closed.
• Another and more preferred method is to have both reactors running, but from pipe 9, only high-temperature steam is injected.
• the activated carbon is collected into dry directly.
• the second method has surprisingly been found to be apt to give higher quality of the activated carbon char. This is believed to be due to that the high-temperature steam injected from pipe 9 makes the pores of the activated carbon opening in the second reactor 4.
• Activated carbon having wider pores than in the prior art may thus be obtained by means of the method of the invention.
• the size (diameter of pores) can be controlled by the temperature of steam in the reactor 4. Generally, a higher temperature of steam increases the pore number of the activated carbon.
• the present invention is capable of achieving a bi-generation (gas and activated carbon) from one and the same feedstock 1.
• the desired ratio of the products can be decided upon according to the type of feedstock available, price of the products, and so on.
• this invention can be used to treat both coarse particles (diameter larger than 0.5 cm) of carbonaceous materials and fine particles and or liquid feedstock.
• Figure 3 shows a cross-sectional view of the gasifier 21, which shows the tangential liq- uid/fine particles feedstock injection.
• Two injection lances 19 (19a and 19b) are shown connecting to the reactor 4.
• Liquid feedstock such as the liquid residues collected after a micro- oven pyrolysis process of the Automotive Shredder Residue (ASR), and fine or pulverized feedstock can be injected into the reactor 4.
• the injected feedstock enters into the reactor 4 tangentially and mixes with the high-temperature air/steam coming from the grate 5.
• the tan- gential injection can increase the residence time of the liquid and/or fine feedstock.
• the entrained flow gases pass through the upper fixed bed grate 8, then enter reactor 3 before leaving the gasifier at the exit pipe 12.
• the injection port 19 should be located to the lower part of the hearth of the reactor 4 in order to increase the residence time. Generally, for a small-scale gasifier, the location of this injection port(s) is 10 cm above the inclination wall 17.
• the residue time can be controlled by the injection velocity, and the angle of the injection lance to the gasifier.
• the walls of the gasifier consist of two layers: an outer steel cover, preferably 5.0 mm thick, and an inner layer of fibrous ceramic insulation, preferably a high temperature resistant, high quality ceramic.
• the ceramic used at walls 13 and 14 can prefera- bly operate with, i.e. withstand, a maximum temperature of 1400 0 C.
• a suitable material may be composed of: Al 2 O 3 45%, SiO 2 36%, Fe 2 O 3 , 0.9% and CaO 16%.
• the ceramic used for the walls at 15, 16 and 17 is preferably apt to operate at a higher temperature of 1400-1500 0 C.
• the maximum allowed working temperature of this wall material is 1600 0 C.
• a suitable material may have the following composition: Al 2 O 3 61%, SiO 2 26%, Fe 2 O 3 , 0.5%, CaO 2.6%, ZrO2 2.95%, and BaO 3.3%.
• the ceramic materials are supported by a steel shell.
• refractive ceramic tubes are used as the grates 8 and 5.
• the composition of these ceramic tubes can for example be 97% ZrO 2 , and 3 % of MgO.
• a high temperature mixture of steam, optionally together with air or oxygen, being fed through pipe 9 enters the throat 18 which below the grate 5.
• This high temperature mixture of air and steam can keep the ash in a molten state in the throat 18, which ash finally drops to the bottom 6, and can be taken out in batches.
• Ash content (SS-187171) 0.5-0.6 % (dry)
• RDF Refuse Derived Fuel
• Ash content (SS-187171) 6.0 % (dry)

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