FR2882046A1 - INSTALLATION FOR PRODUCING HYDROGEN OR GAS SYNTHESIS BY GASIFICATION - Google Patents

Abstract

A hydrogen synthesis gas production plant comprises a bottom bed gasification reactor 101 fed with coke balls Bc and with heated metal balls Bmc. The flow of the balls is downward. The gasification zone 104 is supplied with coke balls through a pipe 106 descending to the middle portion 105 of the reactor from a furnace 103 which supplies coke balls at a temperature greater than or equal to a cracking temperature of the tars and hydrocarbons. The flow of gasification gas produced in the gasification zone 104 rises through the pipe 106 against the current of the coke balls, which makes it possible to bring it to a cracking temperature of the tars and hydrocarbons, in a high part. of driving. The Gg cracking gases thus produced are extracted in this zone. They are conditioned by a suitable device 200, capable of supplying hydrogen or a synthesis gas. The coke balls are advantageously composed of pyrolysis cokes produced on site or at another site.

Description

INSTALLATION FOR PRODUCTION OF HYDROGEN OR GAS

GASIFICATION SYNTHESIS

  The present invention relates to an installation for the production of hydrogen or synthesis gas, from an initial charge, by gasification.

  Typical initial charge is any combustible solid material with high carbon content (> 20%), moderate to low moisture content (50 to 5%) and a relatively low ash content (<30%). It can typically be coke produced by pyrolysis, forest biomass, plant or animal biomass, household or industrial combustible waste, industrial sludge or treatment plant, oil residues, coal, oil sands, oils heavy or mixtures of these materials. It is possible to process in parallel to a solid load majority of liquid fuels with a high hydrocarbon content.

  A new application for the recovery of initial charges is the production of gas for the synthesis of biofuel by so-called Fischer-Tropsch processes. These processes are particularly suitable for upgrading coke from pyrolysis of biomass. The so-called Fischer-Tropsch processes require gases of particular composition, including tar contents, in particular, are very low, typically less than a few mg / Nm3 of gas. These processes also require gases with a very low content of gaseous hydrocarbons (methane, ethane, ethylene, etc.) and pollutant gases for the catalysts (CS2, H2S, HCl, etc.).

  Another application is the production of gas for the generation of hydrogen for the fuel cell feed. Such an application requires gases free of tars, carbon monoxide and pollutants. Hydrogen is also used in industrial petrochemical applications, for the generation of synthetic fuels, ammonia, etc.

  Typical gasification plants use mainly fluidized bed reactors of different types (circulating, dense and / or driven). This equipment is characterized by maximum operating temperatures of 950 ° C to prevent melting of fuel ash and sand forming the bed, which, if it occurs, creates agglomerates which force the installation to be shut down for cleaning operations. . At these operating temperatures, the gasification gases have high tar and hydrocarbon contents (of the order of a few grams / Nm3 of gas).

  The reaction temperature necessary for complete cracking of tars is indeed higher, of the order of 1100 to 1200 ° C., and higher than the melting point of the ashes of biomass or coal (950 ° C.). It is thus very difficult to directly produce gases compatible with the new applications of biofuel synthesis or hydrogen production with fluidized bed reactors of the state of the art.

  On the other hand with the entrainment of dust and high temperatures, unwanted deposits occur on the cold parts of the installation. These deposits can be catalyzed by pollutants present as traces in the treated biomass. They require periodic shutdown of boiler and reactor refurbishment facilities.

  Alternatives have been proposed which consist of adapting the fluidized bed facilities to achieve, after the fluidized bed, a cracking at high temperature gasification gas, typically 11001200 C.

  The cracking gases thus obtained are then cooled and purified from their undesirable compounds by known chemical engineering methods.

  The resulting installations of this design are complex, expensive in investment and low yield. Their control is delicate and requires sophisticated control systems.

  A major problem posed by the production of hydrogen and / or synthesis gas quality from gasification facilities of the state of the art is thus the high production cost of these facilities that use technologies unsuited to the conditions regulatory (standards, safety, quality ...) and market (price, volumes, quality ...).

  An object of the invention is to solve these various problems.

  An idea underlying the invention is to use a bed of heated balls down into the reactor and comprising high temperature coke balls, which provide part of the heat input and heated metal balls, which have a function of extra heat and grinding of the coke balls. The gasification reaction occurs in a gasification zone in the middle part of the reactor.

  More particularly, very high temperature coke balls, typically 1200 to 1300 C, are fed into a central portion of the gasification reactor by a pipe, to supply the gasification zone. The gasification gases produced in the gasification zone go up in the countercurrent pipe of the coke balls, making it possible to raise the temperature of these gases to an elevated cracking temperature, typically of the order of 1200.degree. C., by exchange. of heat with the coke balls. These latter arrive in the gasification zone, in the middle part of the reactor, at a temperature of the order of 1000 ° C. (typically between 950 ° C. and 10 ° C.).

  In practice, control means using sensors, regulate the flow of balls, to obtain the desired temperatures.

  The pipe is provided in the upper part with a porous wall allowing extraction of the cracking gases.

  The heated metal balls are brought to the middle portion of the reactor by a suitable feed device. They have a function of auxiliary heating and grinding coke balls brought by the pipe. They have a composition capable of catalysing the destruction of tars of gasification gas. Typically, they include nickel. They stand out at the bottom of the reactor. They can be heated again to feed the reactor.

  Since the cracking gases must be cooled in the conditioning phase, in particular for trapping carbon dioxide, the installation advantageously provides for recovering the energy of the cracking gases in order to heat the metal balls. A device for dedusting the cracking gases is thus advantageously provided, which is supplied at the bottom by the cracking gases and at the top by cold (or cooled) metal balls recovered at the bottom of the gasification reactor. The metal balls serve as a cooling medium for the cracking gases, and means for dedusting these gases, by driving. Exit is obtained, heated balls that will be used to feed the gasification reactor, and dust (mineral ash) that will be treated appropriately.

  According to an improvement, a method of adjusting the hydrogen content of the cracking gases is implemented in the dedusting device. This process is commonly known as the reaction of WGS, the Anglo-Saxon acronym for "Water Gas Shift". Water vapor injection nozzles are then provided, in the middle part of the dedusting device. The composition of the metal balls is then advantageously chosen to promote (catalyze) the reaction of WGS. Typically, the composition comprises cobalt.

  At the outlet of the dedusting device, a dedusted and partially cooled gas, which can be easily conditioned by proven devices, is obtained to provide a synthesis gas or hydrogen whose composition meets the needs of the new applications mentioned.

  Thus, as characterized by the invention relates to an installation for the production of hydrogen and / or synthesis gas by reducing the water vapor by carbon in a gasification zone of a gasification reactor.

  According to the invention, the gasification zone is a descending bed of balls comprising coke balls and metal balls at a gasification temperature, and producing a rising flow of gasification gas, and the installation comprises: - an oven capable of supplying coke balls at a temperature greater than or equal to a cracking temperature, a conduit for feeding the heated coke balls supplied by said oven, and opening into a median portion of the reactor for gravitarily supplying the zone a gasification process for coke balls, said pipe enabling the countercurrent gasification gases to be raised upstream of the coke balls, so that the gas temperature reaches a sufficient value when cracked in an upper zone of the pipe, a porous wall being provided in said zone, permitting the extraction of the cracking gases produced, - a supply device for the gasification reactor in bilaterally the heated metal, comprising means for injecting the heated metal balls in the middle portion of the reactor, and means for extracting metal balls at the bottom of the gasification reactor.

  Other advantages and characteristics of the invention will appear more clearly on reading the description which follows, given by way of indication and not limitation of the invention and with reference to the appended drawings, in which: FIG. block diagram, a gasification device according to the invention; cokeball and descending metal ball bed and upstream gasification gas flow; Figures 1b and 1c schematically illustrate an embodiment of such a device; - Figure 2a shows in block diagram form, a gasification device according to a variant of the invention; FIG. 2b schematically illustrates an exemplary embodiment of such a device; FIG. 3 is a block diagram of a device for conditioning a cracking gas supplied by a gasification device according to the invention, for the production of a synthesis gas that can be used for Fischer Tropsch processes; FIG. 4 is a block diagram of a device for conditioning a cracking gas supplied by a gasification device according to the invention, for the production of hydrogen; and FIG. 5 illustrates a gasification and conditioning installation according to the invention, in combination with a pyrolysis installation that can be provided on the same site or on another site.

  FIG. 1 shows a gasification device 100 used in an installation for producing synthesis gas or hydrogen according to the invention.

  It mainly comprises a gasification reactor 101, a steam generator 102 and a static oven 103.

  The reactor uses as a water vapor reducing medium, conditioned coke in the form of coke balls. The coke used is advantageously a coke produced by pyrolysis. This reactor supplies, at the outlet, cracking gas Gc at a temperature of the order of 1200.degree. C., which has a composition which makes it possible, by suitable and inexpensive packaging, to obtain at the outlet a synthesis gas or hydrogen whose quality is compatible with the uses mentioned above.

  In the following, gasification gas is understood to mean the gases produced in the reactor, by reduction of the water vapor V, and which are typically at a temperature of between 800 and 950 ° C., referred to as the gasification temperature. Cracking gas means gas free of tars and hydrocarbons. These are the gases that exit the gasification reactor at a higher temperature, called the cracking temperature. This temperature is typically of the order of 1100 to 1200 C.

  The gasification gas Gg is produced in the gasification zone 104 of the reactor, comprising in the main coke balls Bc and Bmc metal balls at a temperature allowing the reduction of water vapor by carbon.

  The supply of logs is downward.

  More particularly, the coke balls Bc are injected into a static furnace 103, which brings them to a very high temperature, greater than or equal to the so-called cracking temperature, of the order of 1200.degree. C. to 1300.degree. C. The coke balls are preferably heated under an inert atmosphere (CO2) and under slight depression so as to be completely free of their volatile compounds.

  This oven can be an oven powered by electricity (resistance furnace, induction, plasma torch for example). It may be an inert gas circulation oven heated by combustion of gas, fuel, or oxyfuel gas, for example, or any other type of high temperature oven. Its function is to deliver coke balls at a specified temperature to ensure a given cracking gas quality without tar or gaseous hydrocarbons.

  In practice, it is expected that the internal pressure of the furnace 103 is slightly lower than that of the reactor 101, and that the furnace is swept by a flow of inert gas, for example CO2. In this way, any pollution of the gases of the furnace is avoided. cracking with tars from the heating of the coke balls. The flushing gas is typically recycled to the base of the gasification reactor.

  A feed line 106, which descends into said middle portion 105 of the reactor, supplies the gasification zone 104 with heated coke balls.

  In the middle part of the reactor, the coke balls bring the heat and the carbon necessary for the reduction of the water vapor.

  In the stabilized mode of operation, the gasification gas Gg back in the supply line 106, countercurrent coke balls. There is therefore a heat exchange in the pipe between the coke balls, which lose heat, in favor of the gasification gas which gradually increases in temperature, until in a high part 107 of the pipe, a cracking temperature is reached. , which allows the removal of tars and hydrocarbons in these gases. In this upper part 107, the pipe is provided with a porous wall which allows extraction of the cracking gases.

  These cracking gases are composed mainly of hydrogen and carbon monoxide. Carbon dioxide or water vapor may also be present in smaller quantities as well as polluting gases. Tars and gaseous hydrocarbons are absent. Infusible ash dust may remain. Their quantity and their nature is related to the quality of the treated cokes.

  The heated metal balls Bmc are brought to the outlet of the pipe 106 by a suitable supply device.

  They serve as auxiliary heating in the gasification zone 104 and grinding means of the coke balls delivered via the pipe 106.

  In the lower part of the reactor, there is a bed of metal balls maintained.

  The steam V required for the reaction is injected under the bed. It is produced in the main by a steam generator 102 placed at the base of the reactor. The generator produces the vapor V necessary for the gasification reaction by cooling by water injection hot metal balls leaving the reactor. In this way the heat of the balls is recovered to produce the steam. Chilled metal beads Bmf are obtained at the outlet.

  The water is injected under moderate pressure to overcome the pressure of a few millibars created by the vaporization of the water in contact with the hot balls coming out of the reactor. Depending on whether one chooses to extract the ash C in solid form or in solution, one can create a circulation of water in the steam generator.

  A boiler 102 'of steam production is preferably provided, to provide steam V extra, especially in the startup phase. The steam V is then injected by an injection inlet disposed at the base of the reactor.

  Other inputs may be provided at the base of the reactor, above the steam injection inlet, for the injection of gasification media, i.e., gases, vapors, or oxygen.

  In particular, an inlet is provided for injecting oxygen. Oxygen thermally balances the steam reduction reactions by combustion of the residual coke. This oxygen injection is in practice limited to a minimum because of the heat gains made in the reactor by the coke balls and the metal balls.

  In the example, an input is also provided for pyrolysis gases. Such gases will be provided in practice by an initial charge pyrolysis device located on the same site. Pyrolysis gases are usually composed of inert gas (CO2), simple combustible gases (CO, H2), incondensable hydrocarbons at room temperature (CH4, C2H6, C3H8, C4H1o) of light condensable hydrocarbons (alcohols, oils). , heavy oils and tars, acidic or neutral gases (CO2, H2S, HCI, N2 ...) and dust. Their temperature is a function of the moisture content of the load admitted to the pyrolysis oven inlet and the temperature setpoint applied to the pyrolysis furnace.

  It is also possible to inject other gasification media separately or in a mixture, for example air, carbon dioxide, natural gas, vapors of liquid fuels. In particular, in the case of an application located on the site of an oil refinery, it can be provided to inject the tank vents, which contain hydrocarbon vapors, and which represent significant volumes. Carbon dioxide may be useful for accelerating carbon degradation in the reactor by increasing the carbon monoxide gasification gas content. Natural gas is also converted to carbon monoxide and hydrogen.

  An air injection is useful when the synthesis gas produced can contain small amounts of nitrogen (by its destination). Indeed, an injection of air to achieve the combustion of residual cokes is advantageous because less expensive than a nitrogen injection (zero cost of air).

  It is also possible to provide an injection of liquid fuels, for example pyrolysis oils, in the middle part, above the gasification zone 104.

  The heating of the metal balls can be achieved by a static oven 108, of the same type as the oven 103.

  Preferably, it is expected to recover the heat of the Gc cracking gas to heat the metal balls. Indeed, the cracking gases must be treated in a conditioning device 200, in particular for extracting carbon dioxide. This treatment requires a prior phase of cooling of the cracking gases.

  Thus, a device is advantageously provided which makes it possible to cool the cracking gases by heat exchange with cold metal balls Bm.

  In the invention, use is made of a ball-type dust collector 201, in which the cracking gases are injected at the bottom and the metal balls Bm at the top. The metal balls recover the heat from the cracking gases, while carrying with them infusible ash that can be contained in the cracking gases. Heated metal beads Bmc, able to feed the reactor, and infusible ash C, entrained with the balls, are recovered at the outlet.

  These ashes C will advantageously be extracted by means of suitable separation equipment, for example a screen, positioned at the outlet of the distribution pipe.

  The Bmc metal balls which have been injected progressively descend to the base of the reactor via the distribution line 112.

  They are extracted at the bottom of the reactor. These beads extracted at the bottom of the reactor are used to produce the vapor V necessary for the gasification process, by cooling with water in the steam generator 102. The cooled balls Bmf are used to replenish the flow of balls Bm injected into the dust collector 201 and / or in the static furnace 108.

  FIGS. 1b and 1c show two exemplary embodiments of a gasification reactor 101 coupled to a ball-blowing precipitator 201 according to the invention, the second figure representing a device comprising both the static furnace 108 and the ball-blowing precipitator 201 for heat the metal balls.

  The reactor and the dust collector are equipment whose walls are typically made of metal covered with insulating material and refractory material.

  The feed pipe 106 of the coke balls is provided in the upper portion 107 with a porous wall made of finely perforated refractory metal and porous mineral refractory material covering both sides of the pipe.

  The distribution line 112 at the base of the reactor, under the median portion 105 comprising the gasification zone 104, is provided with a porous wall 113 made of finely perforated refractory metal and porous mineral refractory material covering both sides of the pipe. . It brings, in particular, water vapor V, supplementary oxygen O 2, pyrolysis gases Gp, etc.

  In the upper part of the reactor, above the gasification zone 104, it is possible to provide an injection inlet for pyrolysis oils (Hp) or even other liquid fuels.

  The reduction reactions occur in the gasification zone 104 in the middle part of the reactor.

  In the lower part of the reactor, there is a bed of metal balls maintained. At the bottom of the reactor, the metal balls, and the ashes entrained with them, are recovered via the distribution line 112. The balls are cooled by the steam generator 102, and extracted by a suitable extraction system such as a worm gear, a Redler type chain extractor or any other suitable extractor. The extraction flow of the balls Bmf is regulated by a control valve at the outlet of the pipe 112 or by the ball extraction system Bmf.

  These balls can be conveyed to the input of the static furnace 108 and / or the ball-blast separator 201, for example by a bucket elevator (not shown).

  In the example illustrated in Figures 1b and 1c, the reactor 101 and the static oven 103 are arranged in a column. This is an illustrative example of the invention. In practice, the static furnace may not be located exactly above the gasification reactor.

  The static furnace 103 is supplied with coke beads Bc through a buffer storage silo 109 at room temperature (10-40 C). They are dosed by a feed hopper by means of a variable flow device 110 in an isolation lock 111.

  In practice, it is expected that this chamber is swept by a continuous flow of inert gas (CO2) to prevent leakage of combustible gases into the atmosphere and that the pressure in the isolation chamber is kept permanently slightly above atmospheric pressure (0 to +5 millibars).

  The ball dust collector 201 is supplied with cold metal balls Bm by a silo 202 coupled to an isolation lock 203 located at the top. An outlet flange in the upper part allows the exit of the dust-free gases GD. The isolation chamber is swept by a flow of inert gas under light pressure to prevent the escape of gas dusted GD to the atmosphere.

  The metal balls Bm are typically the Bmf beads extracted at the bottom of the reactor. They are delivered to the isolation chamber by a circulation device typically constituted by a bucket elevator at a temperature below 60 C.

  The metal balls run countercurrently from the cracking gases in the ball-blast separator 201, where they are heated up to a temperature of the order of 1000 C. In the lower part of the ball-type dust collector, the heated metal balls Bmc are extracted by a device 204 controlled by a temperature measurement and injected in the middle part 105 of the gasification reactor 101, at the outlet of the cracking line 106.

  Note that in the case where the installation comprises in combination or alternatively, a static furnace 108 for heating the metal balls (Figure 1c), the supply conditions are substantially the same. They will not be described.

  In an improvement of the cracking gas conditioning process, there is provided in the middle part of the ball-blowing apparatus, steam injection nozzles V, arranged at regular intervals. These nozzles make it possible to inject steam V, typically at a temperature of the order of 400 ° C, in order to adjust the CO content of the synthesis gas to a specified value, according to a process known as the gas to water, better known as Anglo-Saxon Water Gas Shift. Continuous analysis of the exhaust gas GD delivered at the output allows to check its quality continuously and control the steam injection accordingly. The steam V is produced by the steam generator 120 and / or the boiler 102.

  In practice, the different flows of coke balls and metal are controlled by means of a control system, using in particular temperature and pressure sensors, and controlled valves, to have the optimum conditions for the production of gas from high quality cracking.

  In particular, the control system of the installation determines, as a function of the temperatures in the different reaction zones, the flow rate of coke balls to be supplied in the static furnace 103, using the supply members 110 of the isolation chamber. 111 of the static furnace 103 and the regulator disposed at the outlet of the distribution line 112 at the bottom of the reactor. The gasification of the coke balls in the gasification reactor and the withdrawal of the metal balls at the bottom cause the coke balls to descend into the supply line 106 and the supply of the static oven 103.

  The control system of the installation controls the temperature of the metal balls at the outlet of the dust collector, to actuate the feed rate of the metal balls, by acting on the feed members of the airlock 203 at the inlet and on an element extraction 204 of the flow of heated metal balls Bmc output.

  The control system of the plant controls the quality of the cracking gas Gc at the outlet, by continuously measuring a sample of the gas. This measurement makes it possible to continuously adjust the steam flow V delivered to the base of the gasification reactor, under the gasification zone 104, by means of a steam control valve V (not shown). The control control system also ensures the continuous analysis of the exhaust gas GD delivered to drive the steam injection V in the dust collector 201.

  In practice, in the case of a production of hydrogen gas, the control system will maintain a slight defect of steam output (Gc) of the gasification reactor and a slight excess of steam output (GD) dudoussousseur ball, for convert the maximum amount of carbon monoxide into carbon dioxide.

  In a variant shown in Figures 2a and 2b, there is provided another static furnace 114, placed between the gasification reactor and the steam generator 102 to produce superheated steam from the steam V. The steam produced by the boiler 102 is then introduced at the base of the furnace 114 by an injection nozzle, through a porous wall 116 provided in a distribution line 115. The metal balls extracted at the bottom of the reactor circulate in the static furnace and are recovered at the outlet of the pipe 115.

  This variant makes it possible to supply steam at high temperature to the gasification reactor. Typically the steam then injected into the reactor is at a temperature of the order of 800 C whereas the steam generator 102 can supply steam at a temperature of the order of 300-400 C. It makes it possible to limit the consumption oxygen.

  The static furnace may be of any type already described for the first furnace 103. The porous wall is of the same type as the wall 107 already described.

  For the rest, the arrangements described in relation to Figures la to 1c apply in the same way to this embodiment and therefore will not be recalled.

  An installation according to the invention allows a reduction of water vapor by carbon in the gasification reactor with a bed of coke balls and heated metal balls Bmc, and supplied with vapor V, with oxygen O2, with pyrolysis Gp, by the distribution pipe or lines 112 and / or 115. The injected gases mix with the vapor and travel in the bed of metal balls maintained in the lower part of the gasification reactor, and whose temperature varies from bottom to the top of 600 to 950 C.

  The metal balls typically comprise steel. They further include nickel and / or cobalt to promote reactions in the reactor and the dust collector.

  The steam is heated to reach the necessary temperature (800950 ° C.) for the gasification of the cokes residing in the median portion 105 of the gasification reactor. These cokes are derived from the coke balls fed via the pipe 106, and ground by the Bmc metal balls.

  The reduction reactions occur in the gasification zone 104. These are the following reactions: The water vapor is reduced according to the reaction: H2O + C -> H2 + CO The carbon dioxide contained in the flue gases 15 residual cokes is reduced partially according to the reaction: CO2 + C> 2CO Gasification gas Gg produced in the gasification zone 104 rise and are channeled, for example by a tubular deflector as shown in Figures lb, 1c and 2b , to be delivered at the point of discharge of the heated coke and metal balls, at the outlet of the pipe 106. In this zone, the coke balls and the metal balls have a temperature of the order of 1000 C. The particles of non-gasified coke contained in the gases, the Coke balls and the metal balls are gravity driven to the gasification zone 104.

  The gasification gas Gg flow vertically countercurrently to the stream of coke balls in the supply line 106. They are progressively brought to the determined cracking temperature. This temperature is a function of the heating temperature of the coke balls (1200 - 1300 C) in the static furnace 103, the length of the pipe and injected and extracted ball flows.

  At the cracking temperature, tars and gaseous hydrocarbons are cracked and completely converted into simple gaseous molecules (hydrogen, carbon monoxide and carbon dioxide).

  The residual of tars contained in the gasification gas is converted according to the reaction: CXHy + x H2O> xCO + (x + yi2) H2 The residual of alkanes contained in the gasification gases is converted according to the reaction: CnH2n + 2 + n H2O * n CO + (2n + 1) H2 The residual steam contained in the gasification gases is transformed until elimination, according to the reaction: C + H2O- * CO + H2 The Gc cracking gases are extracted by depression of the pipe 106 through the porous wall in the upper part 107 and directed to the gas conditioning device 200. Only submicron ash particles remain.

  In FIG. 3, the block diagram of a conditioning device 200 of the cracking gas Gc produced according to the invention is detailed to provide a synthesis gas of desired quality. This device makes it possible to dedust, cool, adjust the composition, decarbonate, and pressurize the cracking gas Gc produced by the gasification reactor.

  The conditioning device comprises a ball-blowing precipitator 201 already described in relation to FIGS. 1a to 1c and 2a and 2b. This ball-shaped dust collector makes it possible to recover any infusible submicron ash and to cool the cracking gases, to bring them to a temperature that is typically less than 150 ° C. In a variant, provision is furthermore made for an adjustment of the CO / H 2 ratio, so that to adjust the quality of the gas, by injecting water vapor V. This device being a flow of controlled metal balls to obtain metal balls heated at a temperature of about 1000 C, the temperature of the gases dust removal at the outlet is not regulated.

  A temperature controller 210 is therefore subsequently planned to adjust the temperature of the dedusted gases. This regulator can typically be a water-gas plate heat exchanger, an air cooler or a low temperature hot water use circuit. The temperature of the gases Gr delivered at the outlet is typically less than 40.degree.

  The cooled gases Gr are sent to a decarbonation device 220.

  Such a device has the function of extracting CO2 carbon dioxide and soluble acid gases contained in the gas to be treated Gr.

  This decarbonation is carried out in a known manner by a solvent injection under high pressure in several liquid jet ejectors 221. These ejectors 221 make it possible to suck up all the product gas Gr. They pour the flow of solvent and gas into a reservoir 222 whose internal pressure ensures the partial solubilization of carbon dioxide and soluble gases. The synthesis gas Gs is extracted from the tank, typically by means of a separator 225 which retains the drops of solvent. This device makes it possible to deliver the synthesis gas at a slightly positive pressure without additional compression operation.

  To extract the soluble gases, there is typically provided an output analysis array which determines the composition of the synthesis gas, so as to determine the soluble gases present, and add the reagents necessary to trap these gases, the solvent used to solubilize the carbon dioxide.

  The internal pressure is maintained at a set point by a discharge valve of the solution contained in the reservoir to an evacuation device, slaved to an internal pressure measurement and a conductivity measurement to measure its level of CO2 saturation. .

  The evacuation device may be typically a solvent / CO2 separation device 223, called a stripping device according to the English terminology. It makes it possible to extract (desorb) the carbon dioxide contained in the solution and to recycle the solvent used towards the jet ejectors 221. A device 224 for relaxing the flow of solvent makes it possible to depressurize the solvent and to send it back to the ejectors jet of the decarbonation device. The carbon dioxide CO2 desorbed from the solution by the device 223 may be partially stored under pressure to ensure that the internal requirements of the installation via a tank, in particular the supply of the flushing gas flows used in the airlock of the gasification reactor and the ball-collector.

  The desorbed carbon dioxide can be sequestered in outlets such as marine (ocean trenches) or geological aquifers, or vented to the atmosphere.

  In a variant shown in dashed lines in FIG. 3, an aquifer 231 is used as an outlet. The solvent used can then be water pumped into the outlet used. In the case where the outlet is a marine pit, the water will be pumped at a temperature below 15 C, and discharged to a depth of at least 1500 meters, which guarantees the long-term trapping of dissolved CO2. The separation device 223 is then essentially used to recover the CO2 for the needs of the installation as inerting gas and / or sweeping.

  An installation according to the invention thus produces little greenhouse gas. In addition, since the gasification device uses energy of external origin for heating the static furnace (s), the amounts of synthesis gas produced per unit of fuel consumed are maximum.

  It may be useful to provide in addition to the decarbonation device, an adsorption equipment for volatile heavy metals (arsenic, cadmium, mercury, thallium ...) that may be present in the gas flow Gr, on a specific media. The specific medium will typically be a fixed bed of adsorbent such as: activated carbon, zeolite, bentonite, etc. This device will preferably be disposed before the decarbonation device, in order to have a cooled and dry gas (no steam). water in the gas Gr).

  Figure 4 illustrates the case of an installation intended for the production of hydrogen. The packaging device then further comprises a device 240 for membrane separation of hydrogen, to treat the synthesis gas stream Gs extracted. Permeate 241 provides hydrogen H 2 and retentate 242 comprises carbon monoxide CO, which is reinjected at the bottom of the bead dust collector (see also Figure 2b).

  FIG. 5 shows a complete initial charge treatment facility C1, which uses a gasification plant for the production of synthesis gas or hydrogen according to the invention.

  The initial charges C1 will typically be plant or animal biomass, coal, solid or liquid fuels or petroleum coke, oil sands This installation mainly comprises a pyrolysis device 400 initial charges Cl, which produces cokes output pyrolysis Ck; a device 300 for conditioning the pyrolysis coke, in Bc coke balls; a gasification device 100 according to the invention, in a bed of coke balls and metal balls, which provides at the output of cracking gas Gc, which are treated in a conditioning device 200. Mineral ash C is obtained at the outlet (typically composed of CaO, MgO, SiO2 ...), synthesis gas or hydrogen, depending on the installation, and CO2 carbon dioxide, which can be sequestered.

  A pyrolysis device comprises a pyrolysis furnace which mainly comprises a rotary drum, in which the initial charge C1 to be treated is introduced. A heating device by hot flue gas circulation placed outside the rotary drum allows the heating of the pyrolysis furnace in stabilized operation. The rotation of the drum ensures the flow of the biomass in the furnace. At the outlet of the oven, pyrolysis cokes Ck and pyrolysis gases Gp are obtained. Pyrolysis oils are also obtained from an oil condenser usually used to purify the pyrolysis gases from which pyrolysis oils are recovered. The incondensable pyrolysis gases that come out of it are usually recycled internally in an afterburner chamber, which produces the hot fumes needed to heat the pyrolysis furnace.

  The characteristics of the pyrolysis cokes are a function of the pyrolysis control parameters. In the invention, the production of pyrolysis coke with low volatile content (high pyrolysis temperature, slow heating rate, low pressure), high specific surface area (steam activation) and small particle size will be sought. (fine grinding).

  In the case where the pyrolysis plant is on the same site as the gasification plant, it is possible to reprocess the pyrolysis gases Gp and the pyrolysis oils Hp in the gasification reactor, as an additional carbon source. In this case, the pyrolysis furnace will be heated with electricity.

  In the case where the pyrolysis plant is not on the same site as the gasification plant, it will be possible to reprocess the pyrolysis oils 5 Hp in the gasification reactor.

  The conditioning device 300 supplies the coke balls Bc for the needs of the gasification reactor according to the invention. This device will generally be provided on the same site as the pyrolysis plant.

  In the usual way, the drum comprises grinding means, typically a batch of balls, and at its end, a screen, typically a frustoconical screen, with a mesh of a few millimeters to separate the resulting coke based on its particle size.

  In the invention, the mesh of the screen is determined so as to recover a coke having a particle size allowing agglomeration with a binder. Typically, it is expected that the particle size of the pyrolysis cokes to be agglomerated is less than or equal to 500 microns. Thus, a dry and finely divided Ck pyrolysis coke is obtained at the outlet, which exhibits optimum characteristics for granulation.

  The conditioning device 300 provides a buffer storage of the pyrolysis cokes thus recovered, acting as dosing hopper. At the outlet of the dosing hopper, the cokes are mixed with a binder, for example starch dosed at about 4%. The mixture is output as a dry powder.

  The balls are then formed by suitable equipment. For example, a granulation plate can be used in which the mixture is delivered continuously. A granulation plate is an equipment for producing beads from a material in the form of a dry powder. The granulation is caused by the rotation of the inclined plate fed continuously by the powder of the mixture to be agglomerated and by the spraying of a binder by means of nozzles, the binder promoting the holding of the granules. The balls produced are evacuated continuously by gravity at the base of the slope that is created in the plate. Depending on the applications and the desired mechanical strength of the beads, the binding agent used may be pure water or water containing starch. Starch is a known binder used for the coking of coke. In a practical example, the starch content of the Coke Bc beads used in the process is of the order of 4% on a gross mass.

  The coke balls Bc evacuated by overflow of the granulation plate, are then screened by a suitable device. The balls of diameter greater than the mesh constitute the flow of coke balls Bc which will feed the gasification reactor 100.

  Beads smaller than the mesh diameter are returned to the granulation plate to be recalibrated.

  In a variant, used as binding agent, sludge sludge treatment plant. It is preferable to use limed sludge whose dryness is of the order of 30%. In a practical example, it is planned to mix the limed sludge with pyrolysis coke, up to 10% by weight.

  In this conditioning mode, the granulation will preferably be carried out by means of a die extruder or a ball press.

  This packaging variant advantageously makes it possible to reduce the production cost of the coke balls Bc. Indeed, sludge is usually intended for landfilling, they are usually available at a negative cost. The most suitable sludge is sludge with a low ash content, preferably from agro-food industries.

  An installation according to the invention with pyrolysis, followed, on the same site or on another site, with a gasification according to the invention to produce a synthesis gas or hydrogen is particularly suitable for treating initial charges CI comprising very wet biomass (40 to 60% moisture on gross mass) with a relatively coarse grain size (50mm x 50mm x 20mm forest chips). More generally, any combustible solid material having a high carbon content (> 20%), a medium to low moisture content (50 to 5%) and a relatively low ash content (<30%) can be advantageously treated by an installation according to the invention. It can typically be forest, plant or animal biomass, household or industrial combustible waste, industrial sludge or sewage treatment plant, oil residues, coal, oil sands, heavy oils or mixtures of these. materials. It is possible to process in parallel to a solid load majority of liquid fuels with a high hydrocarbon content.

  The advantage of treating wet biomass is its low price and the availability of the resource. This raw biomass can be produced at a lower cost by existing forestry operations with the technologies currently used, particularly from the recovery of residues and slash on a forest plot. But the facility also finds interesting applications in the recovery of other waste, especially in petrochemical complexes.

  Such an in-situ pyrolysis and gasification plant is advantageously intended for large to very large-scale industrial installations, of the order of 2 to 10 tons of initial charges processed per hour and per process line. The advantage of having very large capacities lies in economies of scale realized in terms of operating cost (personnel, product transport) and investment. With such an installation, the treated biomass is transformed into carbon dioxide, mineral ash, hydrogen, or syngas. Synthesis gas containing in addition to carbon monoxide, the performance in terms of capture of greenhouse gases are in the case of the production of lower synthesis gas than in the case of hydrogen production.

Claims (16)

  A plant for producing hydrogen and / or synthesis gas by reducing water vapor (V) by carbon in a gasification zone (104) of a gasification reactor (101), characterized in that the gasification zone (104) is a descending bead bed comprising coke balls (Bc) and metal balls (Bmc) at a gasification temperature, and producing a rising flow of gasification gas (Gg), and in that the plant comprises an oven (103) capable of delivering coke balls (Bc) at a temperature greater than or equal to a cracking temperature, a feed pipe (106) heated coke balls provided by said furnace, and opening into a median portion (105) of the reactor for gravitarily supplying the gasification zone (104) with coke balls, said pipe allowing the gasification gas (Gg) to rise upstream against coke balls, so that the temperature gas reaches a sufficient value when cracked in a high zone (107) of the pipe, a porous wall being provided in said zone, allowing the extraction of the cracking gas (Gc) produced, a supply device for the reactor of gasification of heated metal balls (Bmc), comprising means for injecting the heated metal balls into the median portion (105) of the reactor, and extraction means (112) of metal balls (Bmf) at the bottom of the reactor gasification.   2. Installation according to claim 1, characterized in that the reactor comprises at least one steam inlet (V), at the base of the reactor, and / or an inlet for injecting oxygen.   3. Installation according to claim 2, comprising one or more entrances at the bottom of the reactor, for the injection of other gasification media comprising separately or in a mixture of gases, including pyrolysis gas (Gp), air , carbon dioxide, natural gas, vapors of liquid fuels and or one or more inputs above the gasification zone 104, for injecting liquid fuels including pyrolysis oils (Hp).   4. Installation according to any one of the preceding claims, characterized in that it further comprises a static furnace (114) disposed at the base of the gasification reactor (101), supplied with water vapor (V) by a steam generator (102), allowing an overheating of the steam (V) before injection into the reactor, the metal balls (Bmf) being extracted at the bottom of said static furnace.   5. Installation according to any one of the preceding claims, characterized in that the flow of coke balls (Bc) injected into the reactor and the flow of metal beads (Bmf) extracted are regulated so as to reach gasification temperatures. and cracking determined.   6. Installation according to any one of the preceding claims, characterized in that said means for extracting the metal balls comprise means for separating the ash entrained with the balls.   7. Installation according to any one of the preceding claims, characterized in that the metal balls contain steel, and comprise nickel and / or cobalt.   8. Installation according to any one of the preceding claims, characterized in that it comprises a device (200) for packaging the cracking gas (Cc) produced, comprising means (201) for heating metal balls (Bm). by recovering energy from said cracking gas to supply the heated metal bead supply device (Bmc).   9. Installation according to claim 8, characterized in that the metal balls injected into the heating means (201) comprise the extracted metal balls (Bmf) of the reactor.   10. Installation according to claim 8 or 9, characterized in that said heating means comprise a ball sump (201) cracked gas extracted from the reactor, metal balls (Bm) being injected at the top, said gas cracking (Gg) being injected at the bottom and springing in the upper part against the current of the metal balls, the heated metal balls (Bmc) by heat exchange with the cracking gas emerging at the bottom of said dust collector.   11. Installation according to claim 10, characterized in that it comprises means (203) for controlling the flow rate of the injected metal balls (Bm) at the top inlet of said ball-blast collector (201), as a function of the temperature of the balls. (Bmc) at the output of said device.   12. Installation according to claim 10 or 11, characterized in that said ball dust collector (201) comprises steam injection nozzles (V) arranged in the middle part of the dust collector, so as to adjust the CO content. and / or the H2 / CO ratio of said cracking gas, by a water adjustment reaction (PWGS), the metal balls (Bm) flowing in the dust collector providing a catalyst function of said adjustment reaction.   13. Installation according to one of claims 8 to 12, characterized in that the conditioning device (200) of the cracking gas (Gg) comprises means (210) for regulating the temperature of the dedusted and cooled gases (Gr ), followed by decarbonation means (220) of said gases, said decarbonation means for dissolving in a solvent the carbon dioxide present in said gas, and sequestering means (230, 231).   14. Installation according to claim 13, characterized in that the packaging device 35 further comprises a device (240) for membrane separation of hydrogen, for treating the stream of synthesis gas extracted, the permeate (241) providing the hydrogen and the retentate (242) comprising carbon monoxide being injected in the lower part of the bead dust collector (201).   15. Installation according to any one of the preceding claims, characterized in that the coke balls (Bc) comprise coke of fine particle size agglomerated with a starch-type binder or limed sludge.   16. Installation according to claim 15, characterized in that said coke of fine particle size is a pyrolysis coke (Ck), produced by a pyrolysis device (400) internal or external to the installation.