Classifications

• • 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
  • C10J3/74—Construction of shells or jackets
• • 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
  • C10J3/723—Controlling or regulating the gasification process
• • 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
  • C10J3/82—Gas withdrawal means
  • C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
• • 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
  • C10J2300/0953—Gasifying agents
  • C10J2300/0959—Oxygen
• • 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
• • 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
  • C10J2300/1628—Ash post-treatment
  • C10J2300/1634—Ash vitrification
• • 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
  • C10J2300/1846—Partial oxidation, i.e. injection of air or oxygen only

Definitions

• the invention relates to the field of heat treatment of materials in a self-crucible wall reactor, or cold crucible, such as a driven flow reactor.
• the invention is particularly applicable for carrying out a gasification of biomass, pretreated or not, in an allothermal entrained flow reactor.
• the invention can be used to carry out all types of gasification of materials, for example coal, sewage sludge or any type of liquid and / or solid waste containing organic and inorganic elements in order to produce electricity or biofuels.
• the invention is also applicable to carry out thermal treatments of materials in other allothermal type reactors, for example in plasma reactors or reactors in which a fuel gas is added (hydrogen or methane, for example).
• the invention also relates to the heat treatment of material in all types of industrial fusion reactor, for example an asbestos melting reactor for vitrifying asbestos.
• Biomass gasification has essentially been developed for cogeneration-type applications, that is to say for treating biomass and transforming it into thermal energy and electricity.
• One known technique for carrying out such a gasification consists in contacting fine particles of biomass with oxygen at high temperature in a driven flow reactor for example described in documents US Pat. No. 5,620,487 and US Pat. No. 4,680,035.
• Documents US 5,968,212 and DE 4,446,803 describe techniques that make it possible to manage double-component refractory zones and cooled zones to take account of thermal stresses.
• FIG. 1 An example of a driven flow reactor 1 is shown diagrammatically in FIG. 1.
• the reactor 1 comprises an inlet orifice 2 through which the material to be treated 4, for example biomass, and reactant gases 6 such as only oxygen and / or methane.
• the reactor 1 comprises a high temperature chamber 8 (temperature for example between about 1000 ° C. and 1800 ° C.) in which the conversion reactions of the biomass 4 into synthesis gas 10 obtained at a port of output 12 of the high temperature chamber 8.
• the conversion time of biomass 4 into synthesis gas 10, corresponding to the residence time of the biomass 4 in the high temperature chamber 8, is of the order of a few seconds.
• the reactor 1 also comprises a burner 22 making it possible to obtain the desired temperature in the chamber 8.
• biomass contains compounds organic compounds which can be represented in the form of C6H 9 ⁇ i ⁇ 4 + o, 5 (elementary representation) making it possible to obtain synthesis gases such as CO, H 2 , CO 2 , H 2 O or else CH 4 .
• Biomass also contains inorganic compounds formed by all the other elements contained in the biomass (mainly oxides such as CaO, SiO 2 , I ⁇ I2O3, FeO or MgO) and which are likely not to occur. turn into synthesis gas. During the operation of gasification of biomass, these compounds are transformed into ashes.
• Inorganic compounds are non-recoverable elements for the transformation of biomass into fuel (fuel being obtained by recombining CO and H 2 gases to obtain CH 4 ), generate operating problems for treatment plants, environmental problems and require, for certain mineral elements, a re-spreading in the field. Between about 0.5% and 3% by mass of the biomass is in the form of ashes during a gasification operation of biomass in a driven flow reactor.
• the high temperature reached in the chamber 8 of the driven flow reactor 1 allows both:
• the reactor 1 can work under a pressurized atmosphere, for example up to about 80 bar.
• the pressure resistance is supported by a cold wall surrounding the high temperature chamber 8 of the reactor.
• the wall of the chamber 8 must also be able to withstand the high temperature.
• a driven flow reactor can therefore operate under severe conditions of temperature and pressure.
• the biomass particles will pyrolyze very rapidly, releasing partially oxidized vapors taking into account the oxygen present in the chamber 8.
• a reaction is thus obtained providing the heat necessary for the gasification of the biomass coal and heating the mixture.
• Residual ash will melt and become deposit mainly on the wall 8 where they will flow.
• These residual ashes will form a layer of molten ash, or molten ash, and a layer of solid ash acting as thermal insulator between the liquid ash layer and the wall of the chamber 8, also called reactor wall, according to the principle of operation of the reactor in a self-crucible, and forming a so-called self-crucible wall.
• the wall of the high temperature chamber 8 is isolated from the molten ash by a layer of solid ash of thickness, for example between about 1 mm and a few centimeters, for example. example less than or equal to about 5 cm.
• This layer of solid ash forms spontaneously in contact with the walls of the chamber which are cooled by a water circulation system.
• FIG. 3 represents the various elements forming the "multilayer" wall of the high temperature chamber 8.
• Such a multilayer wall is for example described in document US 2005/0108940 A1.
• the outer layer of the wall comprises a forced convection cooling circuit 14.
• This circuit 14 comprises tubes in which pressurized water circulates. These tubes are provided with fins allowing on the one hand to have good mechanical grip against an intermediate layer 16, and on the other hand to form a heat flow collector from the inside of the chamber 8 to the tubes of the cooling circuit 14.
• This outer layer is also designed to withstand the pressure in the chamber 8 during the operation of the reactor 1.
• the multilayer wall also comprises the intermediate layer 16 having a thickness of between about 1 cm and 2 cm of refractory ceramic type, for example based on silicon carbide (SiC).
• This intermediate layer 16 has good thermal conductivity, thus allowing the heat flow to be well distributed between a third layer 18 of solidified ash and the cooling circuit 14.
• This intermediate layer 16 also makes it possible to absorb the thermal shocks in the event of a loss. part of the solid ash layer 18 during operation of the reactor 1.
• the multilayer wall comprises the layer of solidified ash 18 supported by the intermediate layer 16.
• This layer 18 acts as a heat shield and is based on a material (solid ash) of the same nature as that of molten ash 20 which flows on the inner surface of the wall, against this layer of solid ash 18 (this flow is represented by an arrow in Figure 3).
• the reactor when the reactor operates in a self-crucible, a portion of the ash contained in the hydrocarbon feedstock of the biomass solidifies and forms a refractory material.
• the other part of the ash is in liquid form and is recovered at the bottom of the reactor (outlet port 12) and quenched with water.
• the inorganics present in the material to be treated and found in the ashes pose many problems, including the corrosion of the reactor wall by liquid ash. Indeed, the liquid ash can destroy a refractory ceramic physico-chemical interaction (for example by a phenomenon of dissolution) even when these liquid ash have a temperature well below the melting temperature of the refractory ceramic.
• FIG. 2 represents a curve giving, as a function of the value of a ratio of concentrations of elements present in the material to be treated, the operating temperature of the reactor.
• the values of the abscissa axis correspond to those of the following concentration ratio: CaO + MgO + Fe 2 O 3 + Na 2 O + K 2 O
• An object of the present invention is to propose a method of driving, or piloting, or using, deterministic and non-empirical, a reactor type self-crucible, and a method of heat treatment of materials in a reactor with a high temperature chamber and wall self-crucible, which can be implemented for all types of resources, or raw materials, even those whose corresponding reactor operating temperatures are not known, and without damaging the reactor.
• the present invention proposes a process for the thermal treatment of materials in a high temperature chamber reactor with a self-crucible wall, comprising at least one step for determining the liquidus temperature T iiq of the ash resulting from the treated materials. operating temperature of the reactor T dark steady state is then selected such that his T c> T IIQ.
• the operating temperature T fon c of the reactor designates here and throughout the rest of the document the temperature prevailing at the outlet of the high temperature chamber of the reactor, that is to say the temperature of the gas present at the outlet of the high temperature chamber .
• the liquidus temperature of a mixture corresponds to the temperature from which all the constituents of the mixture become liquid.
• Such a method makes it possible to solve the problems related to the inorganics present in the treated materials thanks to an optimal operation of the reactor obtained by a choice of the optimal operating temperature of the reactor according to the nature of the treated materials.
• the method according to the invention therefore makes it possible to achieve optimal thermochemical conversion of the materials to be treated, and more particularly an optimal thermochemical conversion of the inorganics present in these materials, whatever the nature of the materials to be treated.
• the operating temperature of the reactor is adjusted with respect to the chemical properties of the ash, that is to say with respect to the composition of the ashes of the materials to be used. Deterministically, the key parameter of the liquidus T iiq temperature of the ashes from the treated materials.
• the method according to the invention therefore makes it possible to heat-treat materials even if they have never been treated before.
• the The invention makes it possible to modify deterministically the characteristics of the ashes in order to render their treatment compatible with the operating constraints of the reactor.
• this method makes it possible to obtain a thermodynamic equilibrium operation of the reactor, allowing a perfect prediction of the composition of the synthesis gas and a cracking of the methane and the tars.
• the operating temperature of the reactor can also be controlled according to the chemical gasification reactions operating in the reactor during the heat treatment of the materials, that is to say according to the evolution of the composition of the ash from the treated materials. It is therefore possible on the one hand to operate the reactor at a minimum temperature maximizing the conversion to CO and H 2 , and on the other hand to avoid operating the reactor at too high temperatures which would increase heat losses.
• the minimum temperature may therefore depend on the material to be process, the operating pressure of the reactor and the residence time of the material in the reactor.
• the method according to the invention makes it possible in particular to avoid an uncontrolled increase in the thickness of the solid ash layer (thickness obtained of the order of a few centimeters and substantially constant during the steady-state operation of the reactor),
• the invention also relates to a method for the thermal treatment of materials in a high temperature chamber reactor with a self crucible wall, comprising at least the steps of:
• T iiq ⁇ T 2 modification of the initial composition of the materials by quantified addition of inorganic melting compounds, that is to say, making it possible to lower the liquidus temperature of the initial composition, such as the liquidus temperature T iiq2 of the ashes of the modified composition of the materials is less than T 2, then determination of the operating temperature of the reactor Tf onc steady state such that T dark> T dark and Ti IQ2 G [Ti; T 2 ],
• T iiq ⁇ Ti modification of the initial composition of the materials by quantified addition of refractory inorganic compounds such as the liquidus T iiq2 temperature of the ashes of the modified composition of the materials is greater than Ti, then determination of the operating temperature of the reactor T steady state function such that T func > T iiq2 and T func G [Ti; T 2 ].
• the method may further comprise the steps of:
• the operating temperature of the reactor T dark steady state can be chosen such that T dark> T LIQ2.
• the invention proposes a quantifiable method thus making it possible to modify this initial composition so that the ash from the modified composition have a liquidus temperature which is compatible and optimal for the operation of the reactor.
• T func can be chosen such that 30 0 C ⁇ (T func - T iiq ) ⁇ 100 0 C and / or 30 ° C ⁇ (T func - TiXq 2 ) ⁇ 100 0 C.
• the thermal losses in the reactor and the thickness of the solid ash layer formed on the reactor wall depend in particular on the difference between the operating temperature of the reactor and the liquidus temperature of the ashes from the materials to be treated, it is therefore possible to reduce the heat losses. in the reactor, which can be less than about 100 kW / m 2 , by bringing the operating temperature of the reactor steady to the liquidus temperature of the ashes from the treated materials (deviation less than or equal to about 100 0 C).
• it is possible to monitor the evolution of the operating temperature of the reactor by measuring heat losses (for example by performing a heat balance on the cooling of the walls of the reactor) with a constant ash composition.
• the initial composition of the treated materials may be modified such that the liquidus T ilq2 temperature of the ash resulting from the modified composition of the treated materials may be between about 1200 ° C. and 1800 ° C., for example between about 1400 ° C and 1600 ° C, or between about 1300 ° C and 1500 ° C, or between about 1300 0 C and 1600 ° C, or between about 1450 0 C and 1550 0 C.
• the initial composition of the treated materials such as the liquidus T iiq2 temperature of the ash resulting from the modified composition of the treated materials can be between about 1400 ° C. and 1600 ° C.
• this temperature range it is possible to lower this temperature range by a value between about 100 0 C to 200 0 C when the residence time of the treated material in the reactor is increased, which increases the energy efficiency of the process.
• this temperature range [0 1400 C 1600 0 C]) can be increased by a value between about 100 ° C to 200 ° C.
• the modification of the initial composition of the treated materials such as liquidus temperature Ti iq 2 for ashes of the modified composition of the processed material is between about 1400 ° C and 1600 0 C, or between about 1300 ° C to 1500 0 C, or between about 1300 ° C and 1600 ° C, or between about 1450 ° C and 1550 ° C, may comprise at least one step of adding inorganic compounds to the initial composition of the treated materials that can substantially equalize the concentrations of SiO 2 and CaO in the modified composition of the treated materials.
• the initial composition of the treated materials may be modified by at least one step of adding MgO and / or Fe 2 O 3 and / or K 2 O and / or Na 2 O and / or P 2 O 5 and and / or CaO and / or SiO 2 , as a function of the liquidus temperature T iiq2 of the ash resulting from the modified composition of the desired treated materials.
• the liquidus temperature of the ashes resulting from the modified composition of the treated materials can be increased.
• the thickness of the solid ash layer of the self-crucible wall of the reactor may be less than or equal to about 5 cm, or between about 1 cm and 2 cm, and / or be substantially constant during the operation of the reactor.
• its operating temperature T func The operating temperature of the T dark reactor may be between about 1000 0 C and 1800 0 C, and for example between about 1400 0 C and 1600 ° C for a biomass treatment.
• composition of the ash formed on the reactor wall can be analyzed at least once, and preferably several times, during the heat treatment process for a given resource.
• the self-crucible wall reactor may be of the driven flow type and / or the treated materials may be biomass.
• the process can be implemented preferably for large capacity reactors, that is to say whose flow of treated materials can be greater than or equal to about 50 tons / hour.
• the method may use a device for rapidly measuring the content of inorganic compounds and ashes of the treated materials, and a device for automatically adjusting the composition of the treated materials according to the operating temperature of the desired reactor.
• the liquidus temperature of the ashes from the treated materials can be determined by a software of thermodynamic calculations.
• FIG. 1 schematically represents a driven flow reactor used during a heat treatment process for materials, object of the present invention
• FIG. 2 represents a curve making it possible to determine empirically the operating temperature of a driven flow reactor as a function of the composition of the treated materials
• FIG. 3 schematically shows a self-crucible wall of a high temperature chamber of a driven flow reactor used in a heat treatment process materials, object of the present invention.
• the driven flow reactor 1 comprises a high temperature chamber 8 comprising a "multilayer" wall (layers 14, 16, 18 and 20) formed during the self-crucible operation of the reactor 1.
• thermodynamic modeling of the multilayer wall of the driven flow reactor 1 is described below.
• the different contact temperatures between the layers 14, 16, 18 and 20 of the wall involved during the operation of the reactor 1 are:
• T f0nc the operating temperature of the reactor 1, that is to say the temperature of the gas present at the outlet of the high temperature chamber 8 of the reactor 1,
• Ti / S oiid the interface temperature between the liquid ash layer 20 and the solid ash layer 18,
• Tiimer / soiid the interface temperature between the solid ash layer 18 and the intermediate layer 16 based on a refractory material, in this case SiC,
• Tiimer / water the interface temperature between the intermediate layer 16 and the cooling circuit 14.
• Ssoiidcish thickness of the solid ash layer 18.
• the thickness of the intermediate layer 16 is known. As a result, the temperature difference over the thickness of the intermediate layer 16 can be determined by:
• a temperature difference of between about 100 ° C. and 200 ° C. is thus obtained. This temperature difference therefore remains small compared to the difference between the temperature of the gas (for example between about 1400 0 C and 1600 0 C) and that of the cooling water (equal to about 100 ° C).
• a thickness of the solid ash layer 18 of between about 1 and 2 cm, and for example equal to about 1.5 cm.
• the interface temperature between the solid ash layer and the liquid ash layer (Ti s / so ix d ) is derived from "steady state" metallurgical considerations.
• Reactor steady state operation means that flow rates, compositions, and temperature distributions are established and do not change over time. This means in particular that the flow of liquid ash 20 is established and that the solid ash layer 18 is established and that its thickness no longer varies.
• the interface temperature between the liquid ash layer and the solid ash layer therefore corresponds to an intrinsic property of the ash, thereby decoupling the temperature in the high temperature chamber from the temperature within the wall.
• the temperature in the liquid ash layer 20 is greater than Ti s / n iicu ash flowing along the wall of the high temperature chamber, that is to say, the ash present in the diaper 20 , are completely liquid (no solid).
• the thickness of the liquid ash layer 20 varies between about 0.5 mm and 2.5 mm for a reference viscosity of about 1 Pa ⁇ s.
• the average flow rate of liquid ash varies between about 2 mm / s and 20 mm / s.
• the Reynolds number remains very low, for example equal to about 10 ⁇ 5 , which confirms the laminar flow regime of the liquid ash 20.
• the thickness of the liquid ash layer increases by a factor of between about 4 and 10, just as the average flow rate decreases by the same factor.
• the conduction thermal resistance associated with the liquid ash layer varies here between approximately 5.10 ⁇ 4 and 2.10 ⁇ 3 K. W "1 ⁇ m 2. This means that for an average heat flow equal to approximately 100 kW / m 2 , the temperature difference over the thickness of the liquid ash layer is of the order of 50 ° C. to 200 ° C. The taking into account of the radiation makes it possible to reduce this difference in temperature by a factor of between approximately 1.5 and 3. The temperature difference over the thickness of the liquid ash layer then falls between about 30 0 C and 70 0 C.
• the liquidus temperature of the ash is an intrinsic property of the ash.
• the basic components of an ash are oxides, of which silica (SiO 2 ) and calcium oxide (CaO) are the most important in quantity. These species thus form the reference system for the analysis of the evolution of the liquidus temperature Ti iqu of ashes according to the composition of these ashes. For example, for an ash composition comprising approximately 2 kg of CaO and 1 kg of FeO, the variation of Ti iqu as a function of the amount of SiO 2 is such that:
• low melting oxides such as for example K 2 O or Na 2 O, which are significantly present in the biomass ash (up to 20% by weight), may reduce the Ti iqu close to 200 0 C.
• SiO 2 can play either the role of flux (reducing Ti iqu ) or refractory (increasing TiCl) depending on the initial concentration of CaC (respectively SiO 2 ).
• the liquidus temperature of an ash can therefore vary between about 1150 0 C up to more than 1600 ° C depending on the composition of the ash, or even, for an ash very rich in calcium oxide, up to a temperature greater than about 2000 ° C.
• the operating temperature of the reactor is therefore chosen to be higher than the liquidus temperature of the ash from the treated materials.
• Ti g / S is equal to T iiqu + ⁇ T s i ag , with ⁇ T s i ag temperature difference over the thickness of the liquid ash layer.
• ⁇ T s i ag is small in comparison with Ti iqu .
• Ti iqu is a good approximation of Tig / S.
• h gas is directly related to gas flow and thermal radiation. It appears that the heat losses are directly proportional to the gap dark T - T iiqu.
• the heat losses can be reduced by comparing the operating temperature of the reactor with the liquidus temperature of the ash.
• the operating temperature of the reactor can be chosen greater than about 50 0 C to 100 0 C compared to Ti ic.
• Can preferably be selected as dark T is about 50 ° C ⁇ (func T - T liq) ⁇ 100 0 C.
• the temperature difference T.sub. -Ti iqu controls both the heat losses and the thickness of the solid ash layer of the reactor wall.
• T func - Ti ic 100 0 C By taking 10 kW / m 2 .K as typical side gas exchange coefficient (in the high-temperature chamber) and a temperature deviation T func - Ti ic 100 0 C, there are thermal losses in the order of about 100 kW / m 2 and a solid ash thickness of about 1 cm. These heat losses correspond to less than 1% of power loss for a driven flow reactor operating at 50 bars and processing a flow of about 50 tons / hour of biomass.
• the composition of the ashes during the process will be monitored to ensure that the liquidus temperature does not vary more than about 50 ° C. Maintaining this temperature range therefore amounts to maintaining the proper composition range ashes.
• the initial composition of the treated materials has a liquidus temperature ash from these materials that does not allow to choose an optimum operating temperature, for example when liquidus this temperature is too high
• it is possible to adjust the composition by modifying it in order to modify the liquidus temperature of the ashes resulting from the modified composition of materials.
• This modification is, in this case, for example carried out by continuous additions of inorganic compounds melting to the initial composition of treated materials, throughout the heat treatment of these materials.
• the operating temperature of the reactor may be chosen in particular to allow the reforming of tars and methane. In particular, it is possible to choose an operating temperature of less than about 1500 ° C., for example equal to about 1250 ° C. If it is desired to operate the reactor at this temperature level, it will then be possible to reduce the liquidus temperature of the ashes to about 1150 ° C. if the liquidus temperature of the ashes resulting from the initial composition of the materials processed is greater than this value.
• the liquidus temperature of the ash can be reduced by incorporating Na2 ⁇ 0, K2O or other low melting point oxides into the initial composition of the treated materials.
• a modification of the initial composition of the treated materials, thus modifying the composition of ash in the reactor and thus modifying the liquidus temperature of these ashes, by additions of compounds can be preferably carried out when the ash content (i.e. the initial content of inorganic compounds) of the treated materials is low (eg the case of wood).
• composition Cl is rich in SiO 2
• composition C2 is balanced in CaO and SiO 2 ,
• composition C3 is rich in CaO.
• compositions of the ash Cl, C2 and C3 are detailed in the table below.
• the liquidus temperature of the ash from the treated materials is preferably calculated from a thermodynamic calculation software for reasons of cost and speed.
• a thermodynamic calculation software for reasons of cost and speed.
• the liquidus temperature of the ashes is determined by means of a modeling software whose models base on experimental data established with ashes of different compositions.
• a modeling software whose models base on experimental data established with ashes of different compositions.
• the liquidus temperature can for example be measured by a method of microscopic observations after a quenching of a small quantity
• the liquidus temperature of the ashes can also be measured in situ by X-ray diffraction at high temperature.
• the liquidus temperature of the ashes can also be approached by a differential thermal analysis - thermogravimetric analysis (ATD-ATG), a calorimetric method consisting in following the evolution of the temperature difference between the sample studied and a control body. inert.
• ATD-ATG differential thermal analysis - thermogravimetric analysis
• the desired operating temperature is between about 1400 0 C. and 1600 ° C.
• the materials from which these ashes are obtained can be modified as follows:
• the liquidus temperature of the ashes is further reduced by adding fluxes, that is to say additions of K 2 O and / or Na 2 O and / or P 2 O 5 and / or MgO and / or or Fe 2 O 3 .
• the composition of the ash C2 can also be optimized by reducing the liquidus temperature of these ashes by adding a flux, for example Fe 2 O 3 or MgO (according to the ash compositions, the MgO can have a melting character if it it is added in small quantities).
• a flux for example Fe 2 O 3 or MgO (according to the ash compositions, the MgO can have a melting character if it it is added in small quantities).
• the operating temperature of the reactor can be modified in particular by adjusting the flow rate of oxygen (reactant gas) at the inlet of the high temperature chamber.
• oxygen reactant gas
• the gasified material in the heat treatment process described here is pretreated biomass, for example in the form of small particles, of a solid suspension in an organic liquid (or "slurry” in English), of char ( biomass coal) using techniques such as fluidized beds, slow pyrolysis, roasting or grinding.
• the particle size of the treated materials and the addition of fluxing agents are therefore two parameters which make it possible to optimize the yield the reactor by minimizing the need for oxygen for combustion.
• the cooling carried out by the cooling circuit 14 makes it possible to form the layer of solid ash of sufficient thickness to thermally protect the wall, and particularly the intermediate layer 16.
• the characteristic time of setting up the solid ash layer 18 is inversely proportional to the flow rate of the reactor 1. For example, in the case of a reactor of industrial size (that is to say, whose flow is greater than or equal to about 50 tons / hour, the solid ash layer 18 may in about six hours, while for a small reactor (flow rate equal to about 50 kg / h), the solid ash layer will be formed after about 5 days.

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