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
  • C10B27/00—Arrangements for withdrawal of the distillation gases
  • C10B27/06—Conduit details, e.g. valves
• • 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
  • C10B49/16—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 moving solid heat-carriers in divided form
  • C10B49/20—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 moving solid heat-carriers in divided form in dispersed form
  • C10B49/22—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 moving solid heat-carriers in divided form in dispersed form according to the "fluidised bed" technique
• • 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
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
  • C10B57/02—Multi-step carbonising or coking processes
• • 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
  • C10J3/482—Gasifiers with stationary fluidised bed
• • 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
  • C10J3/54—Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
• • 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
  • C10J3/58—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels combined with pre-distillation of the fuel
  • C10J3/60—Processes
  • C10J3/62—Processes with separate withdrawal of the distillation products
• • 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
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K1/00—Purifying combustible gases containing carbon monoxide
  • C10K1/02—Dust removal
  • C10K1/026—Dust removal by centrifugal forces
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C10/00—Fluidised bed combustion apparatus
  • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
  • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
  • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
  • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/02—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment
  • F23G5/027—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment pyrolising or gasifying stage
• • 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
  • C10J2300/0953—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
  • C10J2300/0976—Water as steam
• • 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
  • C10J2300/0983—Additives
  • C10J2300/0993—Inert particles, e.g. as heat exchange medium in a fluidized or moving bed, heat carriers, sand
• • 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
  • C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
  • C10J2300/1807—Recycle loops, e.g. gas, solids, heating medium, water
• • 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

Definitions

• the invention relates to circulating fluidized bed (CFB) reactors for thermal processing of added carbonaceous material, and to processes for manufacturing combustible product gas having a higher heating value between 4-8 MJ/Nm 3 from such a carbonaceous material by subjecting the carbonaceous material to pyrolysis in one process step and oxidation in another process step.
• CFB circulating fluidized bed
• the document WO 99/32583 discloses a method and apparatus for gasification of solid carbonaceous material comprising a circulating fluidized bed (CFB) gasifier constituted as described in Figure 1 of the document by a pyrolysis reaction chamber (1), a particle separator (2) for separation of char-containing particles from the outlet gas (32) of the pyrolysis reaction chamber, a char reaction chamber (3), having at least one inlet for particles from the particle separator, and means for further recirculating particles from the char reaction chamber to the pyrolysis-reaction chamber.
• the dual chamber CFB gasifier's operation may be controlled in different ways.
• the disclosed apparatus and process functions well at comparatively low temperatures, beneath 750o C.
• this system is particularly well suited for organic biomass, waste streams and energy crops which contain a relatively high concentration ( > 0.2%) of elements such as Potassium and Phosphorus, which tend to exist in or form low melting ash components.
• Decomposition of added carbonaceous material by the previously disclosed apparatus can be increased by adding extra fluidized bed reaction chambers between the primary char reaction chamber, where char particles are gasified, and the pyrolysis reaction chamber, where new carbonaceous fuel material is added.
• serial positioning of one or more fluidized bed char reaction chambers between the recirculating separator and the pyrolysis reaction chamber (1) can cause temperature control problems. The temperature tends to increase in each subsequent fluidized bed char reaction chamber because the char decomposition reactions are primarily exothermic, in contrast with the primarily endothermic pyrolysis reactions which prevail in the pyrolysis chamber.
• the primary char reaction chamber In normal operations, it is generally advantageous to maintain the primary char reaction chamber at a temperature that is as high as possible, but still beneath the threshold for ash agglomeration. Endothermic pyrolysis reactions typically drive the temperature in the pyrolysis reaction chamber down to levels on the order of 80 to 200 o C lower than the temperature in the primary char reaction chamber. A subsequent additional fluidized chamber placed between the primary char reaction chamber (3) and the pyrolysis reaction chamber (1) will, even if constituting as little as 10 % of the total char converting bed area, typically increase the overall maximum process temperature by an additional 5-20°C higher than the temperature in the primary char reaction chamber.
• Figure 1 shows one embodiment of a CFB reactor according to the invention indicating the relative position of units and conduits through which gas and particles flow.
• Mean temperature in a chamber refers to the temperature at a level corresponding to half the height of the chamber.
• the invention provides a circulating fluidized bed (CFB) reactor for thermal processing of added carbonaceous material, comprising: - a first pyrolysis reaction chamber (1) wherein added carbonaceous material is pyrolysed due to contact with hot recirculating particles, which first reaction chamber (1) has an inlet (1a) for carbonaceous material, an inlet (1 c) for fluidizing gas, and an outlet (1 b) for product gas in the upper part of the first reaction chamber (1) which product gas carries carbon containing char particles and recirculating inert particles,
• CFB circulating fluidized bed
• one or more separators (4) having an inlet (4a) through which the product gas carrying particles from the first reaction chamber (1) is received, and an outlet (4b) through which the particles leave each separator and enter into a primary char gasification chamber (5) via one or more conduits (14),
• said primary char gasification chamber (5) comprising an inlet (5a) for pyrolysed and recirculating particles, an inlet (5b) for fluidizing gas (6) in the lower part of the primary char gasification chamber (5), an outlet (5d) in the upper part of the primary char gasification chamber (5) for produced gas and an outlet (5c) for particles in the lower part of the primary char gasification chamber (5) opening into a particle return conduit (7) which particle return conduit (7) opens into an intermediate char gasification chamber (9), and
• said intermediate char gasification chamber (9) comprising an inlet (9a) for particles from the primary char gasification chamber (5) and an inlet (9b) for a fluidizing gas e.g. containing 0 2 /H 2 0 in the lower part of the reactor (9), and further comprising an outlet (9c) for produced gas carrying particles from the upper part of the chamber (9) which outlet (9c) opens into a conduit (8) having at least one outlet to the lower part of the first reaction chamber (1) and which provides fluidizing gas to the first reaction chamber (1).
• a first fluidized bed (1 1) of particles is provided in the primary char gasification chamber (5), the volume of said first fluidized bed (11) is defined as the volume present above the level of adding the fluidizing gas at the bottom of the fluidized bed and up to the surface of the same fluidized bed, above the volume of the first fluidized bed (11) is a lower density freeboard volume (13) containing gas and entrained fine particles.
• particles are transported through the intermediate char gasification chamber (9) forming a second fluidized bed (10) of particles where the volume of said second fluidized bed (10) is defined as the volume above the level of adding the fluidizing gas at the bottom of the fluidized bed and up to the center of the outlet (9c) for produced gas and particles in the upper part of the intermediate char gasification chamber wherein the height (h 10 ) of the second fluidized bed (10) in the intermediate char gasification chamber (9) is larger than the height (hn) of the first fluidized bed (1 1) in the primary char gasification chamber (5).
• particles are transported through the intermediate char gasification chamber (9) forming a second fluidized bed (10) of particles where the volume of said second fluidized bed (10) is defined as the volume above the level of adding the fluidizing gas at the bottom of the fluidized bed and up to the center of the outlet (9c) for produced gas and particles in the upper part of the
• a small amount of fluidizing gas (usually air), typically less than 15% of the flow of product gas, is added through nozzles distributed in the bottom of the pyrolysis chamber, in order to keep particles freely flowing and well mixed.
• the reactor is configured such that nozzles through which fluidizing gas may be introduced are located within the bottom 15% of the pyrolysis chamber. As used herein a nozzle is located within the bottom 15% where the distance from the bottom surface of the pyrolysis chamber is 15% or less of the total distance between the bottom and top surface of the pyrolysis chamber.
• the reactor is configured such that the top of the intermediate char gasification chamber is placed at a level that is intermediate between the levels of the top and bottom of the primary char gasification chamber.
• the level is
• the reactor is configured such that the top of the intermediate char gasification chamber (9) is placed at a level that is higher than that level of the primary char gasification chamber (5) at which the majority of fluidizing gas is introduced.
• the reactor is configured such that greater than 50% of the internal volume of the intermediate char gasification chamber is placed at a level beneath the level of the primary char gasification chamber at which the main part of fluidization gas is introduced.
• the inlet (1 c) for fluidizing gas and particles from the intermediate char gasification chamber (9) is positioned below i.e.
• outlets for ashes can be provided from one or several of said reactors (1 ,5,9) as well as from one or several of the separators (4).
• the cross-sectional area of the intermediate char gasification reactor is at least 50% and preferably at least 75%smaller than the cross-sectional area of the primary char gasification chamber (5).
• the CFB reactor is configured such that the inlet (1 c) for fluidizing gas from the intermediate char gasification chamber (9) is positioned below i.e. upstream all inlets (1a) for carbonaceous material into the pyrolysis reaction chamber (1).
• a process for manufacturing a product gas having a desirable heating value from a carbonaceous material comprising
• a first process step where the carbonaceous material is introduced into a first pyrolysis reaction chamber in which are flowing a fluidization gas having a low 0 2 content and hot inert recirculating particles, and in which the temperature ⁇ is between 400 and 850°C, producing a product gas which carries partly converted particles i.e. char and recirculating bed particles out of the first process step,
• a third process step conducted in a primary char reactor, where carbonaceous material remaining in the separated char is subjected to a decomposing oxidation treatment in a fluidized bed at a temperature T 2 between 600 and 850°C, producing a product gas which is withdrawn from the upper part of the primary char reactor and which product gas, fully or primarily, enters the first process step, together with a fraction of fine entrained particles, while bed particles from the lower part of the primary char reactor are transferred to a fourth process step, and - a fourth process step, where remaining char is subjected to a second decomposing oxidation treatment in a fluidized bed at a temperature T 3 between 600 and 850°C, producing a product gas which, together with recirculating particles, exits the fourth step and enters the first process step as a fluidization gas,
• the first process step is conducted in an atmosphere having a low content of 02, typically ⁇ 1 % or less than 5%.
• the retention time t 10 > 1.2 t i and preferably > 1.5 in .
• the temperature T 2 of the third process step 15 and the temperature T 3 of the fourth process step differs with less than 10°C, i.e. T 3 - T 2 ⁇ 10°C, normally T 3 - T 2 ⁇ 5 0 C.
• the temperature ⁇ is between 400 and 750°C, normally between 625 and 775°C, and even more preferably between 720 and 20 770°C.
• the temperature T 2 is between 650 and 850°C, normally between 700 and 800°C.
• the temperature in the first process step is controlled by regulating the flow of fluidization gas into the fourth process step which to the major part determines the flow of fluidization gas and recirculated particles into the first process step.
• at least 95 wt% of the bed material in the third process step is inert particle material while at most 5 wt% of the material is carbonaceous material in the form of char.
• the carbonaceous material fed to the pyrolysis reactor as fuel has a content of ashes above 1 % by weight and might have an ash content between 5-50% by weight.
• the carbonaceous material used as fuel has a high content of greater than 0.2% by weight or greater than 0.3% by weight potassium (K), chlorine (CI) and/or phosphor (P) including in some cases, for example cereal straw, rice straw, and related grain cleaning waste streams; residues from further crops including sugar cane, sorghum and beets, maize, potato, nuts, tea, cotton, olive, wine and oil palms, Algaes - eg. including sea weed, and potential further marine/aquatic derived organic material; energy crops such as grasses - incl. eg.
• Miscantus - and short rotation forest based on fast growing wood like Willow and Poplar Crops having an elevated content of salt due to e.g. growth in proximity with salty water or having other contact with salty water; residues from meat production industry such as meat and bone meal; animal manure including dewatered manure slurry; Municipal and industrial organic waste, including organic fractions derived from such streams, sewage sludge, etc.; energy containing residues such as fiber and lignin products from processing wood and raw organic products such as those mentioned above by means of e.g. hydrolysis, extraction and fermentation etc.
• any of the above listed carbonaceous material may be used as fuel, regardless of potassium (K), chlorine (CI) and/or phosphor (P) content.
• Figure 1 shows an embodiment of a CFB reactor according to the present invention and illustrates how the units of the CFB reactor can be connected.
• the figure shows a first reaction chamber 1 provided with an inlet 1a through which inlet 1 a carbonaceous material is fed through a conduit 2.
• the first reaction chamber 1 further comprises an outlet 1 b for particle loaded product gas, an inlet 1c for fluidization gas and an inlet 1d for product gas from a primary char gasification chamber 5.
• Said fluidization gas added thorough inlet 1 c may be supplemented by the addition of more fluidization gas added through one or more nozzles providing for a satisfying distribution of gas and particles in the bottom part of first reaction chamber 1.
• embodiments of CFB reactors according to the present invention comprise a first reaction chamber 1 wherein carbonaceous material is pyrolysed due to contact with hot recirculating particles. That the carbonaceous material is pyrolysed means that the material is decomposed due to heating and not due to oxidation; pyrolysis is an endothermic process requiring addition of heat.
• the hot circulating particles transporting heat to the first reaction chamber 1 is normally sand but might be any inert particulate material being adequately resistant to wear.
• a feed of carbonaceous material is fed to the first reaction chamber 1 through a conduit 2 and an inlet 1a;
• the carbonaceous material can be any carbonaceous material such as organic material, coal or products based on petroleum but normally the carbonaceous material is an organic material such as straw or other vegetable waste, soft lignocellulosic biomass such as agricultural residues, manure, household rubbish, dried wastewater, dried animal remains or other dried carbonaceous waste products, optionally mixed with inorganic material
• the first reaction chamber 1 has a supply of fluidizing gas in the bottom of the chamber which fluidizing gas provides a fluid bed for reaction and transport of particles in the first reaction chamber, the particles are transported from the bottom of the chamber to a top outlet 1 b of the first reaction chamber 1.
• the atmosphere in the first reaction chamber 1 is kept low in oxygen in order to reduce the occurrence of oxidizing reactions according to which the carbonaceous material partly ends up as C0 2, and H 2 0, i.e.
• fluidizing gas is provided primarily from the intermediate char gasification chamber 9 in which chamber char oxidizing reactions occur which produce heat and which reduce oxygen content of the product gas leaving the chamber 9.
• some supplemental fluidizing gas may also be added directly to chamber 1.
• the optimum temperature in the first reaction chamber 1 depends on what kind of carbonaceous material is being gasified and also the purpose of the product gas and residual ash/solid products. It is typically advantageous to choose a temperature in the first reaction chamber 1 which is sufficient to make the carbonaceous material decompose to a high degree while the temperature should not be high enough to cause agglomeration of the decomposing material and recirculating bed material. Moreover, environmentally problematic and therefor unwanted polyaromatic hydrocarbons (PAH) tend to be produced at high pyrolysis temperature. Normally if the carbonaceous material is a usual organic material, the mean pyrolysis temperature will be advantageous between 400 and 800 °C.
• the temperature will more typically be between 620-700°C and for very low heating value fuels such as anaerobically digested and dewatered manure from farming animals and such as pre treated sewage sludge, the temperature will more typically be between 500-600°C. Even lower pyrolysis temperatures can be chosen e.g. for the purpose of producing bio oil and/or bio char.
• the temperature in the first reaction chamber 1 is during operation normally controlled mainly by adjusting air flow into the intermediate char gasification chamber 9 and/or by adjusting the total amount of particles in the gasifier.
• the reaction chambers might be heated to temperature of operation by the use of extra burners - and/or after such initial heating also by adding fuel and air/oxygen to e.g. the first reaction chamber 1.
• the product gas via one or more conduits 3 enters into one or several parallel separators 4 via inlets 4a, the product gas, together with a fine fraction of the particles, leaves the separator 4 through an outlet 4c entering a conduit 18 and the separated particles exits the separator 4 through an outlet 4b entering a conduit 14.
• the conduit 14 transports the particles to the bottom of a char gasification chamber 5 where the particles are received in a fluid bed 1 1.
• the purpose of the separators 4 is to separate the product gas from the main part of the entrained particles as this main part of the particles have to be conveyed to the primary char gasification chamber 5.
• the particle separation can be performed using any type of particle separator such as dynamic separators, e.g. turn chamber- , labyrinth, and cyclone separators, or barrier filters, e.g. high temperature bag filters, porous ceramic filters or granular bed type filters, including combinations of the mentioned separators.
• the product gas from the first reaction chamber is first cleaned in a primary dynamic separator and thereafter in a secondary, more effective type separator.
• the re-circulation of particles to the char gasification chamber 5 is in this case primarily performed from the first mentioned primary dynamic separator.
• the secondary separator may e.g. be just a more efficient cyclone separator or a highly efficient barrier filter.
• the conduit 14 transporting particles from a separator to the primary char gasification chamber 5 will be provided with means or so constructed that gas is prevented from rising from the primary char gasification chamber 5 through the conduit 14 and enter into the separator.
• Char particles are oxidized at the temperatures prevailing in the char gasification chamber by introduction of a gasification agent. Where oxygen is directly added, the oxidation reaction produces a partially combustible gas, is exothermic and increases temperature in the char gasification chamber. However endothermic, steam-based char conversion reactions can also be conducted which produce a partially combustible gas but which serve to lower temperature.
• the double purpose of the primary char gasification chamber 5 is to heat up the inert re-circulating particles and to optimize char conversion i.e. to optimize recovery of combustible gas from the
• the primary char gasification chamber 5 comprises an inlet 5a for pyrolysed and inert recirculating particles, it also comprises an inlet 5b for fluidizing gas which in the figure is supplied via a conduit 6 in the lower part of the primary char gasification chamber 5.
• the fluidizing gas is normally supplied to the primary char gasification chamber 5 through many nozzles(not shown) and/or other air distributing means assuring a flow pattern suitable for maintaining a fluid bed in the chamber.
• the primary char gasification chamber 5 has a bubbling fluidized bed in the lower part.
• the gasification agents also serves as the fluidizing gas and is a mixture of mainly air and some steam (H 2 0) which will increase the temperature overall- but the char gasification chamber may also have one or more more-or-less separate inlets for liquid gasifying agents such as water- which will more effectively than steam lower the temperature in the chamber.
• the primary char gasification chamber 5 comprises an outlet 5d in the upper part of the char gasification chamber 5 for gas and an outlet 5c for particles in the bottom part of the char gasification chamber 5.
• the outlet 5c opens into a particle return conduit 7 which particle return conduit 7 opens into an intermediate char gasification chamber 9 through inlet 9a.
• the mean temperature in the primary char gasification chamber 5 will normally be at least 50°C higher than the temperature in the first reaction chamber 1 , which will normally mean that the particles entering the first reaction chamber 1 via the inlet 1 c is at least 50°C higher than the desired operating temperature in the first reaction chamber 1.
• the temperature in the primary char gasification chamber 5 is normally kept below 770°C.
• the atmosphere in the primary char gasification chamber 5 contains oxygen which results in that exothermic oxidizing reactions take place in the primary char gasification chamber 5.
• the oxygen content in the atmosphere of the primary char gasification chamber 5 during operation is high enough to decompose most of the char material by oxidation.
• the oxygen content in the added gasification agent is maintained well below sub-stoichiometric levels, meaning that there is insufficient oxygen to fully oxidize all of the char material added to the primary char gasification chamber 5 via inlet 5a.
• a fluidized bed 1 1 of particles is provided in the lower part of primary char gasification chamber 5.
• the volume of this fluidized bed 1 1 which is normally a bubbling fluid bed is defined as the volume present above the level of adding the fluidizing gas at the bottom of the fluidized bed and up to the surface of the same fluidized bed.
• the height hn of the fluid bed 11 is indicated on the figure.
• the height hn of the fluidized bed 1 1 can be evaluated and maintained on a desired level by measuring differential pressures in the fluidized bed and by comparing these pressures to pressures measured in the freeboard volume 13.
• Said freeboard volume 13 is above the volume of the fluidized bed 1 1 and this freeboard volume 13 contains gas and particles being too fine to remain in the bubbling bed and instead are carried with the gas to the outlet 5d and into the conduit 15.
• the gas can either enter the first reaction chamber 1 through the conduit 17 and the inlet 1d or part of the gas or all the gas can leave the CFB reactor through conduit 16.
• the intermediate char gasification chamber 9 further comprises an inlet 9b for adding fluidizing gas in the lower part of the reactor 9 and this way a fluidized bed 10 is formed in the intermediated char gasification chamber 9.
• the added fluidizing gas is typically mainly air but might also be other gasification agents such as 0 2 and/or steam (H 2 0) while a further gasification agent might be liquid water which might be introduced through separates inlets.
• the intermediate char gasification chamber 9 comprises an outlet 9c for produced gas carrying particles from the upper part of the chamber 9 which outlet 9c opens into a conduit 8 having at least one outlet to the lower part of the first reaction chamber 1.
• the intermediate char gasification chamber 9 provides fluidizing gas to the first reaction chamber 1 and as the gas produced in the intermediate char gasification chamber 9 is deprived of oxygen it is not necessary to add a major amount of further oxygen depleted fluidizing gas to the bottom of the first reaction chamber 1 and in particular the use of inert gas such as N 2 as fluidizing gas can be avoided.
• the volume of the fluidized bed 10 is defined as the volume above the level of adding the fluidizing gas at the bottom of the fluidized bed and up to the center of the outlet 9c for produced gas and particles in the upper part of the intermediate char gasification chamber 9, the height h 10 of this fluidized bed 10 being indicated in the figure.
• the CFB reactor is constructed in such a way that it is possible to make the height h 10 of the second fluidized bed 10, which is defined by the inlet of fluidized air and the outlet for gas and particles, larger than the height hn of the first fluidized bed 1 1 in the char gasification chamber (5).
• the primary char gasification chamber 5 In order to free the energy remaining in the char which constitutes a considerable part of the total energy of the carbonaceous fuel material fed to the CFB reactor, it is desirable to operate the primary char gasification chamber 5 at as high a temperature as possible without risking agglomeration of the particles in the fluid bed. If the highest allowable temperature is obtained in the primary char gasification chamber 5 it will be a problem that the temperature in the downstream fluid bed i.e. the fluid bed in the intermediate char gasification chamber is 10-20°C higher than the temperature in the char primary gasification chamber 5 as this can cause agglomeration of the material and result in shutting down of the CFB reactor or require a lower temperature in the primary char gasification chamber
• > 5% steam may be as high as 0.1 or 0.2 or 0.5.
• the mean temperature in the intermediate char gasification reactor will become lower and it will be possible to maintain a temperature in the intermediate char gasification reaction which is less than 10°C and preferably less than 5°C higher than the temperature in the primary char gasification chamber 5. This also means it will be possible to increase the decomposition of the char in the
• intermediate reactor 9 by increasing the volume of this chamber without having a problematic increase in temperature of approximately 10-20°C compared to the temperature in the primary char reactor 5. Providing the said extra gas retention time in the intermediate reactor and this way converting more char by means of slow endothermal reactions is also a better solution for avoiding said problematic temperature increase than providing e.g. the same cooling effect by just adding extra badly converted steam or water.
• the cross-section of the intermediate char gasification chamber is normally dimensioned to typically - and at approximately the same resulting superficial fluidization velocity - consume a certain amount of gasification agent compared to the mass flow of gasification agent added to the primary reaction chamber 1.
• the fluidization gas travelling through the intermediate char gasification chamber 9 carries heated inert particles and has to be conditioned to adequately low oxygen content and although it would be possible to increase the retention time by reducing the flow of fluidization gas in the intermediate char gasification chamber, the minimum flow of fluidization gas is primarily defined by the need for transport of particles through the chamber.
• the product gas typically has a higher heating value between 4-8 MJ/Nm 3 .
• This range of heating values is typical for mainly air blown gasifiers, while higher heating values can be obtained by using a gasification agent that has a higher content of oxygen compared to Nitrogen..
• the invention also relates to a process comprising the following steps:
• Carbonaceous material is introduced in a first reaction chamber in a fluidization gas having a low content of 0 2 and hot inert recirculating particles, the temperature Ti is between 400 and 850°C. The carbonaceous material is subjected to thermal
• decomposition i.e. pyrolysis. All material i.e. char particles and inert heat transporting particles is by the product gas carried to a top outlet in the first reaction chamber through which the product gas and the particles exits the first process step. There might be an outlet for extraction of ashes e.g. including oversize particles from the bottom of this pyrolysis reaction chamber 1 .
• the product gas carrying particles enters a separation zone where the product gas is separated from the particles, the product gas which has an increased heating value relative to the supplied fluidization gas is either collected or taken directly to consumption, while the separated particles are transferred to a char gasification chamber.
• the remaining carbonaceous material i.e. the char particles is subjected to a decomposing treatment in a fluidized bed at a temperature T 2 between 600 and 850°C.
• the product gas from this process step is withdrawn from the char gasification chamber and enters the first process step e.g. together with a fraction of entrained fine particles. A part of the product gas might be withdrawn from the process instead of entering the first reaction chamber.
• the particles other than particles transferred with product gas or removed for purposes of circulation control are transferred to a fourth process step.
• the still remaining carbonaceous material is subjected to a second decomposing treatment in a fluidized bed at a temperature T 3 between 600 and 850°C.
• a product gas as well as recirculating particles exits the fourth step and enters the first process step as fluidization gas and heat carrying particles.
• the gas retention time (t 10 ) in the fluidized bed in the fourth process step is larger than the gas retention time (tn) of in the fluidized bed of the third process step (t 10 >tn).
• product gas from the fourth process step enters the first process step as fluidization gas below the entrance for carbonaceous material in the first reaction chamber.

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• 2013
  • 2013-07-17 CN CN201380038048.5A patent/CN104704088B/zh not_active Expired - Fee Related
  • 2013-07-17 US US14/415,062 patent/US20150218456A1/en not_active Abandoned
  • 2013-07-17 EP EP13741667.3A patent/EP2875104A1/en not_active Withdrawn
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