EP3408357A1

EP3408357A1 - Method for the gasification of carbonaceous materials and devices for implementing said method

Info

Publication number: EP3408357A1
Application number: EP17710588.9A
Authority: EP
Inventors: Jean Marie Gabriel Charles LUCAS
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-01-28
Filing date: 2017-01-30
Publication date: 2018-12-05
Also published as: MA45438A; WO2017129871A4; WO2017129871A1; FR3047300B1; FR3047300A1

Abstract

The method of the present patent defines how the gases and materials circulate in two, three or four spaces, what conditions are maintained in said spaces and the functions thereof. As a result of said conditions, the gasification produces "clean pyroligneous" gases and leaves ash in powder form. If required, the method can also be used for producing coal that is extracted at the same time as the ash, or for removing the ash from the coal that is mixed with same. The two main spaces specified are a "gasification/carbonisation/drying" space and a space for "raising the gases to high temperature". These spaces can be supplemented by a coal gasification space and/or a finishing space. Three devices are specified that can be used for carrying out the method.

Description

Process for the gasification of carbonaceous materials

and devices to implement it

TECHNICAL FIELD The technical field of the invention which is the subject of this patent is the gasification of carbonaceous material. The carbonaceous material gasification is the transformation of solid or liquid carbonaceous material into a gas (which we will call gasification gas), possibly accompanied by the production of one or more by-products or wastes.

Until today, the gasification of carbonaceous material is mainly considered to derive a fuel gas used to power an engine, a turbine, a boiler, a burner. It is also considered to produce a liquid or gaseous fuel (methanation for example).

Examples of carbonaceous materials that can be gasified include but are not limited to: powder or pieces of biomass, coal, coke, plastic, miscellaneous waste.

PRIOR ART

Generalities on carbonaceous material gasification

In order to gasify coal or coke, it is conventionally used a process requiring the addition of water (advantageously in the form of water vapor) to coal or coke and to supply energy to the assembly. energy is needed to activate and compensate for the strong endothermicity of the gasification reaction, which is called the reaction of gas to water. The gas thus produced is a mixture whose main components, besides the inert gases possibly introduced into the process, are: CO, CO ₂ , H ₂ , H ₂ O and CH ₄ .

When lignified lignocellulose is gasified in a conventional manner, this material undergoes the following different transformations: It is first dried. It is then pyrolyzed. The products of the pyrolysis are finally transformed into gas. The products of this pyrolysis are mainly charcoal and pyroligneous. During drying and then pyrolysis, water vapor (water of moisture and water called "of constitution") is released. Part of this released steam reacts on the pyroligneux and the coal resulting from the pyrolysis and gasifies them. This reaction takes place at high temperature. It produces a gas whose main components, besides the inert gases possibly introduced into the process, are: CO, CO ₂ , H ₂ , H ₂ O and CH ₄ . Depending on the proportions of the various components in the mixture constituting the gasification gas, it has a PCS (higher calorific value) and a PCI (lower heating value) more or less high.

All the work done on the gasification of coal, but also lignites, peat, biomass or household waste (the first work on these subjects dating from before 1900) led to the design and construction different gasifiers (also called gasifiers). The analysis of these different gasifiers, their advantages and their disadvantages, made it possible to identify two particularly valuable qualities for a carbonaceous material gasifier:

- the ability to produce a gasification gas "clean of pyroligneux"

- The ability not to melt or agglomerate ashes, which together with the inert materials mixed with the material to gasify, form the non-combustible part of the carbonaceous material to gasify.

A gas "clean of pyroligneux"

With regard to the ability to produce a gas gasification "clean of pyroligneux", note that:

- If one wants to use carbonaceous gas gas for supplying an engine or a turbine, the fact that the gas is "pyroligneous clean" avoids prematurely damage or degrade this engine or turbine

if it is desired to use carbonaceous material gasification gas for liquid fuel synthesis through processes such as the Fischer-Tropsch process, or to produce methane, the treatment to which the gasification gas must be subjected before to use it in the processes is much less expensive when the gasification gas is "clean of pyroligneux"

- if it is desired to use carbonaceous gas gasification gas as a fuel in a burner, the fact that this gas is "pyroligneous clean" makes it easier to achieve the higher smoke qualities required by the standards

- if carbonaceous materials containing undesirable chemical elements or undesirable compounds of these elements (for example sulfur, arsenic, chlorine, heavy metals, toxic metalloids) are gasified, these elements as well as compounds which contain them, are found in the gasification gas or in the ashes. Although gasification can break down many unwanted organic substances, the presence, even residual, of undesirable elements in the gases or ashes can be bad for humans, the environment or some catalysts, so that a treatment gas from gasifier or ashes may be required. This treatment is much easier when the gasification gas is "clean of pyroligneux"

similarly, harmful compounds can be formed during total or even partial combustion reactions (dioxins-furans and cyanides are particularly thought of). They are much easier to remove gases and ashes when these products are "pyroligneous clean".

All this shows how much a gasification gas "clean pyroligneux" is appreciable.

Ash, melts and agglomerates

With regard to the ability not to melt ashes, this is also an important advantage. The melting or agglomeration of the ashes produced in a gasifier make it difficult to recover them later and can lead to degradations of the gasifier, such as, for example, tearing off refractory layers during cooling of the reactor (which takes place when the reactor is shut down). gasifier). Keeping the ashes resulting from the carbonaceous material gasification in pulverulent form simplifies their extraction from the gasifier, their possible chemical treatment and their reuse, for example by spreading (after treatment if necessary) as mineral fertilizer.

"Clean pyroligneous" gas and ash, no melts or agglomerates

So far, the work done on gasification has not allowed the development of processes capable of producing (except with very stable and precise characteristics of materials or with coke or well-cooked coal) a gas "clean of pyroligneux While avoiding the fusion or agglomeration of ashes.

In conventional gasifiers, the multiple reactions that transform the material into gas take place at about the same time, in different places, with little separation and poor control. They are therefore difficult to control and guide. This is one of the reasons why conventional gasifiers very often produce charged gases, more or less according to the methods, pyroligneux.

It is by making sure that these reactions take place in an organized way, in different spaces between which matter and gas circulate in an organized and possibly forced way, and in which the chemical and thermal conditions are fixed so that some of the different stages gasification are favored (because of the chemical and thermal conditions prevailing in the spaces where they take place), that the gasification process object of the present patent makes the devices that implement it capable of producing a gasification gas "clean pyroligneux" while avoiding to melt or agglomerate the ash from possible incombustibles present in the carbonaceous matter that is gasified.

Flexibility concerning the materials to be gasified

The process which is the subject of this patent can be used to gasify a very large variety of materials without its operation, neither the "pyroligneous cleanliness" of the gasification gas, nor the absence of fusion or agglomeration of the ashes. affected. Now it is very interesting to be able to feed the same gasifier, successively and without particular transition, with carbonaceous materials of different nature and moisture content without degradation of the operation or performance of the gasifier.

"On demand" operation

Another important advantage of the method and devices for implementing it: they can be started and stopped quickly, and can vary their operating regime even faster than you can start and stop. All this without degradation of the quality of gasification gas produced. It is thus possible to operate "on demand" the gasification plants implementing this method and these devices. This is particularly interesting if one wants to adjust to the needs of the moment a production, from gasification gas, heat and / or electricity. This often makes it unnecessary to store gasification gas, the material to be gasified is usually much simpler and less expensive to store than gas.

SUMMARY OF THE INVENTION

As mentioned above, the carbonaceous material gasification process that is the subject of this patent distinguishes different spaces in which different stages of gasification take place and are favored because of the chemical and thermal conditions that prevail in these spaces. The materials and gases circulate in an organized and possibly forced way between these spaces. In this process, the material to be gasified is in a layer that advances in the space or spaces it has to travel from the point of entry of the material in the gasifier to the point where leaves what remains after the gasification of the material: a mixture of coal and ash mixed with the inerts which have been introduced with the material to be gasified. The gases pass through the layer of material, traversing it transversely from the "top of the layer" to the "bottom of the layer", pushed by a means of movement called "main fan".

Space of "gasification - carbonization - drying"

The first step of the process takes place in a space (1) that will be called "gasification-carbonization-drying" space. This space, which contains a part of the layer of matter and the areas that immediately surround it, receives high temperature gases from another space that is called the "high temperature gas elevation" space. we will describe later. These gases arrive on the material by the so-called "top of the layer" by which the gas enters the layer of the material introduced into the gasifier. The very hot gas starts by drying, if the incoming material is not dry, the material on the surface, then warms it and carbonizes it. A little further in the direction of the advance of the layer, the very hot gas arrives on an already dry material and even carbonized (this due to the advancement of the layer of material). He then carbonates a part of it. In doing so, it cools due to the highly ehdothermic carbon gasification reaction by the water vapor that appeared during the process or added. And since this reaction is noticeably active only when the temperature is above 750 ° C, the gas stops cooling by gasifying the carbon when it reaches this temperature. The gas cooled to about 750 ° C, then heats and pyrolyses the material it meets, which cools again until its temperature reaches 200-100 ° (temperature below which the pyrolysis no longer takes place and the heat of the gas can only serve to heat and dry the material.

«Main fan»

After having passed through the layer of material to be gasified in the "gasification - carbonization - drying" space, the gases exit "below" the layer of material. They are then sucked by a means of gas movement that sucks them to cross the layer of material located in the "gasification-carbonization-drying" space and pushes the gas that it has sucked to enter in the "high temperature gas elevation" space. This means is advantageously a fan (5) called "main fan". These gases are a mixture of coal gasification gas, gas pyrolysis of the material introduced into the gasifier and drying gas of this material, which can be observed that the temperature (averaged over the entire length of the layer which is in the space of "gasification-carbonization-drying") is between 250 ° C and 800 ° C. The high value of this temperature requires that the means for moving the gas used, which may be a fan, can operate at a temperature of 800 ° C. As the sucked gas can contain dust that has not been retained by the layer of material, the dust it contains can be deposited, as well as pyroligneous on the elements of the device, for example on the blades of the fan and the unbalance. This is the reason for the use of a radial fan with a temperature resistance of 800 ° as the "main fan". The bearings of this fan must be carefully cooled because there is no bearing running sustainably at 800 ° C. For this, and to be able to pass continuously, on the axis, a temperature of 800 ° C (temperature of the wheel) to a temperature acceptable by the bearings (and especially by the seals which maintain the lubricants used in the bearing) the axis will advantageously comprise one or more sections of "drop in temperature". These sections will advantageously welded assemblies of tubes and cones made of refractory steel sheet (thin, so that it does not transmit too much heat), filled with refractory wool. These sections join the fan wheel to the rest of the axis passing through the fan bearings. The axis is cooled in its part passing through the bearings.

Space for "elevation of gases at high temperature"

The gases, extracted from the "gasification-carbonization-drying" space by the "main fan", are then pushed by this fan into the "elevation of the gases at high temperature" space (19) where their temperature is high. In this space, the gases are brought to high temperature, cracked and modified by the high temperature.

Several ways can be used to raise gases at high temperature: Partial oxidation

A particularly high temperature gas raising means that appears to be particularly simple is the partial oxidation of gases from the "high temperature gas raising" space by means of flame stabilization and homogeneous combustion techniques. This elevation of the gas temperature of the "gas elevation at high temperature" space is obtained by the partial combustion of a certain amount of the gas (also called "fuel") rotating in the chamber which materializes the space "elevation of gases at high temperature", permitted by the introduction into the chamber of a certain quantity of oxidizing gas (called also oxidizing), possibly after reheating obtained by passing through an exchanger. It ensures that the fuel and the oxidant are vigorously mixed with the gases rotating in the chamber, so that the combustion takes place fairly quickly. For the combustion to take place fairly rapidly, it is necessary at the same time that there is an intimate contact between the introduced oxidizing gas and the gases present in the chamber, and that the heat transfer associated with this intimate contact allows the mixture of reach at least the temperature at which the oxidation is spontaneous and fairly fast.

Advantageously, the intimate and rapid contact of the gases is made in the "elevation of the gases at high temperature" space by bringing the gases pushed by the "main fan" into the chamber (which has sucked them into the chamber). bottom of the "gasification-carbonization-drying" space), as well as the oxidant, by one or more fins-shaped ducts penetrating deeply into the "high temperature gas raising" chamber, at the end of which are arranged orifices, so that the turbulence surrounding the jets ensure the mixing of the introduced gases and very hot gases that rotate in the "elevation of the gases at high temperature" chamber. The mixing must take place quickly enough so that if possible in less than half a turn of the gases in the chamber, the temperature of the mixture is such that the combustion reaction takes place. The introduction into the chamber of gases from the "gasification-carbonization-drying" space and the introduction into this chamber of the oxidant are made by orifices that are small enough for the injection speeds to be very different from the speeds from the overall flow in the chamber to the places where the injection takes place. The orifices must also be oriented so as to inject the gases in the direction and direction of the flow. The gas introduction ports may be elongated, circular or other. The velocities of the gases in the orifices, the number, the dimensions and the orientations of the orifices must be such that the quantity of movement transferred from the incoming gases to the gases that rotate in the chamber is sufficient to ensure that, despite the pressure drops due to the presence of the ducts, possibly in the form of fins) in the rotating flow increased by those due to the presence of the walls, the rotational movement in the chamber remains of sufficient intensity.

The regulation of the gas temperature of the "elevation of the gas at high temperature" space is done by regulating the amount of oxidizing gas injected.

In this particular case of a gasifier with high temperature rise of the partial combustion gases in the "high temperature gas raising" chamber, the oxidizing gas (mixed with the inert gas associated therewith) may advantageously have been, before it is introduced into the chamber, reheated, for example by passing through a heat exchanger transferring heat from the gas leaving the gasifier to the gas containing the oxidant.

Plasma arc or electrical resistance It is also possible to obtain the rise in temperature of the gases in the "elevation of the gases at high temperature" space by an electric heat supply: plasma arc or high temperature electrical resistance. In the case of electric heating, it is possible to regulate the temperature of the gases in the chamber of the "high temperature gas raising" space by adjusting the power of the electric heating device.

By partial oxidation or by other means, it is thus possible to raise the gases of the "elevation of the gases at high temperature" space at high temperature.

"Gasification of coal" space

Another step intervenes optionally in the process: the "gasification of coal" stage which takes place in the space of the same name.

The gases leaving the "elevation of gases at high temperature" space are directed:

for a part towards the "gasification-carbonization-drying" space "above" the layer of material to gasify that they will cross

for the other part towards the "coal gasification" space, if there is one, here also "above" the layer of material present in this space.

In the "gasification of coal" space, the layer of material is completely charred throughout its thickness. As it progresses in the "gasification - carbonization - drying" space, it is no longer remained of the initial layer as a completely carbonized layer. The gases coming from the space of "elevation of the gases with high temperature", which arrive on this carbonized layer no longer contain pyroligneux, the pyroligneux having been cracked almost completely because of their stay at high temperature in the presence of vapor of water for a sufficient time in the chamber. They are therefore gases already cracked by their stay in the space of "elevation of gases at high temperature" which leave the space of "gasification of coal", after crossing the layer of coal and ash which remains in this space. It should also be noted that, in the event that the cracking would not have been complete in the elevation chamber of the gases at high temperature, the gases would complete their cracking by crossing, in the "gasification of coal" space, the layer of well-cooked charcoal and ashes therein.

The "gasification of coal" space is advantageously geometrically in the extension of the "gasification-carbonization-drying" space (FIGS. 3, 4, 8). In the particular case, for example a layered gasification on a grid, the grid that supports the layer of material in the "gasification of coal" space can advantageously be an extension of that which supports the layer of material in the "gasification-carbonization-drying" space.

When they leave the process, the gases leaving the "gasification of coal" space and which are the "gases produced by the process", have just crossed the coal layer in the "gasification of coal" space. They are therefore about 750 °. They can therefore, by crossing a counter-current heat exchanger (or cross-current exchangers assembled against the current), raise the temperature of the gases which contain the oxidant possibly introduced into the space of "high gas elevation". temperature "up to about 600-700 ° C (the flow rates of the two fluids are indeed about the same if we take air as oxidant). This rise in the temperature of the gases that contain the oxidant significantly improves the gasification efficiency.

In a revolving-gate version, the "gasification-carbonization-drying" and "gasification of coal" spaces are above a rotating circular grid that carries with it the layer of matter from the entrance of the material ( where the material falls on the grid) to the outlet of the charcoal-ash mixture (where the charcoal-ash mixture is ejected).

It should be noted that the "gasification of coal" space is not essential for the process: In the case where one only seeks to produce heat with the biomass that one gasifies, one is not obliged to pass the gases (which go towards the boiler or to another thermal use) by a "gasification of coal" space. Some of the gases leaving the "high temperature gas elevation" space go into the "gasification-carbonization-drying" space and the other part is sent directly to the boiler in which these gases will be produced. subject of a post-combustion.

It should also be noted that, whether or not there is a "gasification of coal" space, it is possible for the gasifier to be released, mixed with ashes (and as far as possible), more or less less coal mixed with ashes. The process settings may be such that the gasifier is removed as little coal as possible or, on the contrary, as much coal as possible.

Space of "finishing"

The process finally also, possibly also, another step called "finishing". This step takes place in a space called "finishing space" in which we introduce the mixture of ash and coal that comes out at the end of the "gasification" space. coal "if there is one or at the end of the" gasification - carbonization - drying "space if there is no" gasification of coal "space.

The "finishing" space allows for the depletion of coal ash and / or the cooling of the mixture of ash and coal that comes out at the end of the layer of material undergoing or having undergone gasification. This space may advantageously be provided with a column on top of which is introduced the mixture of ash and coal and at the bottom of which the ash is extracted (or almost) coal and / or a mixture of coal and ash , pretty cool. But it can also be equipped with a more complicated system, such as, for example, a column with permeable walls supplemented by a recirculation fan and a heat exchanger. In this case, the mixture of ash and coal goes down in the column. This column with permeable walls is traversed by gases recycled by a fan and which are, themselves, cooled by a sealed exchanger placed in their path. In the permeable column, the mixture of charcoal and ash may gradually burn to coal and / or cool.

In the "finishing" space, almost all or a portion of the residual carbon is gasified with water vapor. It is advantageous to provide some or all of the heat at high temperature which allows this gasification by a partial combustion of air. However, in order to prevent the temperatures in the finishing space from becoming too high in places, it is advantageous to introduce into this space a mixture of air and water vapor, so that in contact with the coal remaining in the Ashes, an endothermic vapogasification of coal, concomitant with oxidation by oxygen in the air, maintains the whole at a temperature around 750 °, which is below the melting temperature of the ashes. This introduction is easily done by humidifying the air that is introduced into the "finishing" space. The humidification is advantageously by bubbling (prior to the introduction of the mixture into the finishing space) air in a water advantageously around 80 ° C. The quantity of air and the quantity of associated water introduced into the "finishing" space will be proportioned so that the oxygen content of the gas leaving the finishing space is as small as possible. The gas leaving the "finishing" space is in fact mixed with the gas leaving the "elevation of the gas at high temperature" space and is, therefore, reintroduced into the whole of the gas circulation which takes place in the gasifier. If the amount of oxygen it contains is quite low, this introduction does not have a negative impact on the process

MANNER OF REALIZING THE INVENTION Various types of gasifiers

Various devices can implement the method described above: there will be mentioned, by way of non-limiting examples, three:

an inclined bed gasifier in which the "high temperature gas elevation" space is separated from the "gasification-carbonization-drying" space and in which there is no space for coal gasification "because the very hot gases leaving the" high temperature gas raising "space that do not go to the" gasification-carbonization-drying "space go directly into well-insulated pipes to a a device known as a "lean gas burner" installed in the combustion chamber of a boiler, in which room the combustion of gas produced by the gasifier takes place, at the place where it would take place, in the case of the use of a conventional burner, the flame of this burner.

• an inclined laying bed gasifier in which there is a common "gasification-carbonization-drying" and "coal gasification" space which is not physically separated from the "high temperature gas elevation" space, except below the layer of material.

a cyclone fluidized bed gasifier in which the layer of material to be gasified is suspended in a cyclonic gas flow.

Devices used in the various sets of devices for carrying out the process - a device which allows the material treated therein to enter the gasifier while separating the surrounding atmosphere from all internal spaces at the gasifier. This device is essential if one wants to be able to maintain, near the place where the material enters, a slight depression in the gasifier, without this slight depression causes an unacceptable air intake into the gasifier. However, maintaining a slight depression in the gasifier (and also in the ducts and devices located downstream of the gasifier) is essential if one wants to eliminate any risk of leakage that would allow carbon monoxide to spread in the gasifier. 'atmosphere. This device may advantageously be a set of valves and double valves.

In the example installation, the "gasification-carbonization-drying" space and all the spaces that are connected to it are separated from the atmosphere by a double valve (31). This double valve allows the material to enter all the spaces connected to the "gasification-carbonization-drying" space while preventing the air from enter into this set of spaces where one can, thanks to this seal, maintain, at the point where the material to gasify, a pressure very slightly lower than the atmospheric pressure. - A grid and a device that ensures the movement of the layer of material over the entire length of the grid. Two different versions of grids, each adapted to the training system associated with it will be described:

- The first drive system uses a piston (7) thin, flowing in the direction of the slope of the grid, on the surface of the grid, below the layer of material that is to move. This piston is moved by tubes arranged in the direction of the slope, resulting in a transverse bar fixed to the tube. The piston is immersed in the layer of material (3) to gasify. It moves on the top of the grid and below the layer of material to gasify which is placed on the grid. By advancing and retreating at times, it causes, due to the shape of its cross section and due to the slope of the bed, a movement of the layer of material down the bed, making it advance on the bed. is pushed by one or more (advantageously 2) advantageously round tubes and steel which are sealed and filled with water and steam, so that they react thermally as a heat pipe which ensures a good cooling of the part of the tube which is in contact with the products of the layer of material being gasified. The "piston drive" tubes are advantageously set in motion by a cable or chain (with return strand) moved by a gear motor (26). A properly positioned pulley ensures that the gearmotor drives the piston tubes in both directions (lowering and raising the piston). The tubes pass through the wall which limits the closed space filled by the gasification gas, using a metallic device (because of being able to withstand medium temperatures) through which a wall penetration (13) which seals as much as possible (using in case of need of the woven ceramic braid).

the grid itself consists of angles in strips of folded refractory steel sheets, connected together by welding points so that they constitute T (9). The T are arranged in the flow direction of the layer of material to gasify which is placed on the grid consisting of T assembled so that there is between them a longitudinal slot through which the gases flow. Below the layer of T that supports the material is another layer of so-called "interstitial"T's (10), which ensures that the falling material of the slits of the first layer of T does not fall completely. The layers of T are welded to transverse plates (11) which, advantageously, are attached to the longitudinal edges of the grid, which edges rest on slides (12) attached to the walls of the gasifier. A sheet metal (14 and 15) can recover ashes or particles that fall under the bed. Another allows to recover the mixture of coal and ash, at the end of the bed. the second system uses "special inverted angles" made from strips of folded refractory steel sheets, or flat strips of refractory steel sheets welded together. The layer of material is placed on a set of "special inverted angles" oriented in the direction of the slope of the grid and which advance and retreat successively in the direction of the grid, retreating one after the other, then advancing all together. The "special reverse angles" are based on turned angles that serve as fixed guides. The inverted angles are arranged so that there remains, throughout the length, between the "special inverted angles", a slot sufficient for the passage of gases. The "special inverted angles" are based on the turned angles fixed on transversal plates, themselves fixed on longitudinal profiles. The set of angles angles-transverse plates-longitudinal profiles constitutes a support on which slide the "special inverted angles" on which the layer of material is laid. "Special inverted angles" are moved so that they are driven, one by one or in defined groups, according to a defined program.

Below the grid, the "gasification-carbonization-drying" space is separated from the "gasification of coal" space (if it exists in the apparatus under consideration), by a material partition (16). The clean gases that have passed through the coal layer of the "coal gasification" space are "pyroligneous" are grouped below the bed and exit through a pipe (18). As they have remained separated from the gases leaving the zone of "coal gasification" by a material wall they are "clean of pyroligneux"

- connection ducts between devices and in particular between the "gasification-carbonization-drying" space and the entrance of the "main fan" as well as between the output of the "main fan" and the "elevation chamber" high temperature gas "The main fan is connected to the" gasification-carbonization-drying "space, below the grid, by a short pipe (22) provided with expansion joints (23). The output of the main fan is also connected to the entrance of the "elevated gas elevation" space by a pipe (24) also provided with expansion joints (25). These connecting ducts must be sufficiently well insulated. For this purpose they will advantageously consist, from the inside to the outside: of a hardener layer covering the ceramic wool. -A layer of ceramic wool providing thermal insulation. -A sheet constituting the sealing wall. If necessary, a standard 200 ° resistant insulating layer that can be coated on the outside with a protective coating or an aluminum outer shell. The outer banal insulation layer is intended to avoid that the sheet is in operation at a temperature below the dew point of the gasification gas.

- Connections between two sections of pipes and between a pipe and a device such as, for example fan, can flexibly connect the stainless steel parts that seal the gasification gas circuit and absorb the deformations due to temperature changes. These flexible couplings, because they must withstand high temperatures can advantageously use the flexibility of thin sheet metal parts of stainless steel.

Bed gasifier with separate spaces

This type of gasifier, according to the process object of this patent, was designed to heat a set of agricultural greenhouses.

It includes a "gasification-carbonization-drying" space in which the material to be gasified arrives. This material is layered as soon as it has crossed the double valve which separates the atmosphere from all spaces of gasifier, double valve that avoids, when feeding the gasifier material, too much air enters it, although a slight depression is maintained in the zone near the material inlet of the "gasification-carbonization-drying" space.

The gases that arrive on the "top" of the layer of material in the "gasification-carbonization-drying" space passes through this layer by gasifying a portion (more or less important depending on the gasifier setting), coal that is present in the charred part of the layer. The gas that comes out below the already carbonized layer, the one coming out of the part a little closer to the entrance of the material of the layer being carbonized, the one finally coming out, loaded with the moisture of the drying of the material, from the zone to the entry of the material, is the result of the gasification, carbonization and drying carried out by the gases coming from the space of "elevation of gases at high temperature" which have been sucked by the so-called "main" fan, below the layer of material, in the space of "gasification-combustion-drying" and are pushed back into the set of fins that bring these gases deeply into the "high temperature gas elevation" space of the gasifier.

In this gasifier, the high temperature gas elevation chamber is physically separated from the portion of the gasifier that houses the "gasification-carbonization-drying" space. The "main fan" discharges the gases that it has sucked below the "gasification-carbonization-drying" space (gas that will be called "the fuel"), while another fan pushes it back. air (which will be called "the oxidizer") The fuel and the oxidant are mixed by jet effect with the partially burned gases that turn in a circle in the "high temperature gas elevation" chamber and with this mixture reach a temperature sufficient for their self-ignition to take place.

Part of the partially burned gases and at high temperature (which are the result of a combustion which is only partial and have a PCI of "poor gas" then leaves directly, by a heat-insulated pipe, towards the boiler of the installation greenhouse heating.

In the boiler of the greenhouse heating plant, the gases are burned in the combustion chamber which usually houses the flame of a fossil fuel burner. The "poor gas" burns, thanks to a device that is called "poor gas burner". The fumes coming out of the boiler are sucked by a fan and, after passing through a cooling tower, leave, saturated with water and cooled, into the atmosphere by a chimney.

Another part of the gases goes above the layer of material in the "gasification-combustion-drying" space. It is she who then crosses, in this zone, the layer of material to gasify.

At the downstream end (in the direction of flow of the material layer), which is also the lower end of the grid, there emerges a layer of ash which can, depending on the operating settings of the system, contain very little or a significant amount of coal. The ashes, mixed with coal, fall through a double damper into a reserve of ashes.

The near-proud has no space for "coal gasification" or "finishing" space. Its "gasification-carbonization-drying" space is materially different and is separated from the "elevation of gases at high temperature" space. The elevation of the gases at high temperature takes place in a cylindrical chamber equipped with ignition burners which serve to warm the chamber at the start of the installation The elevation of the gases at high temperature is obtained by partial oxidation of the gases which turn in the chamber, and the rotation of the boxes therein are driven driven by the jets coming out of orifices located in the trailing edge of aerodynamic fins introducing by two joint channels, forming a single fin, the fuel is the competitor in the room that. '

Space-packed bed gasifier in which the high temperature elevation space is just above the "gasification-carbonization-drying" spaces and (if any) of the "coal gasification" space

In another stand-up gasifier, the "high temperature gas elevation" space is located just above the "gasification-carbonization-drying" and "gasification of coal" spaces and is part of a a single construction incorporating the "high temperature gas lift" chamber, the underside of the bed, the grid and all the parts associated with the grid, the "main fan" and all the necessary plates. In this second type of gasifier bed posed, the main fan is block with all .. It sucks also, according to the method, below the zone of the bed located in the "gasification-carbonization-drying" space, at the bottom of this space. Its outlet always blows according to the process, in the space of "elevation of the gases with high temperature" which is here located above the bed and that a large longitudinal slot puts in direct communication with the high part of a spaces "gasification-carbonization-drying" and "gasification of coal".

In this way, the high-temperature gas mass, which rotates in the "high temperature gas elevation" space, allows the full length of the "high temperature gas lift" chamber "Gasification of coal", its outermost layer of gas, which immediately arrives on the upper surface of the layer of material that the gas must pass through.

In this second type of bedded gasifier, the gasification air is introduced into the gas that rotates in the "high temperature gas elevation" chamber, by a slot at the trailing edge of an aerodynamically shaped pipe. arranged parallel to the length of the chamber, which duct is fed by a fan, possibly through an exchanger if it is desired to heat the gasification air. The gasification air exits at high speed from the slot at the trailing edge of the aerodynamically shaped pipe which brings and distributes the air into the chamber. It is essentially this air which, despite the pressure losses imposed on it by the walls and the fins as well as the air supply line, transmits to the gases that rotate in the chamber, the amount of movement necessary for them to continue to turn.

The gases sucked by the "main fan" below the "gasification-carbonization-drying" space are discharged by this main fan into a small box which feeds the fins which penetrate the rotating flow which takes place around the water. axis of the "elevation of gases at high temperature" chamber. The aerodynamic shapes of the fins and the air supply duct avoid too much disturbance of the flow in the chamber where the gases rise at high temperature.

Fluidized bed gasifier

In a third gasifier, suitable for easy-to-suspend products, the material layer is not supported by material elements, but by the cells that tangentially enter through a longitudinal slot of the quasi-cylindrical inner wall of the reactor and rotate. , along and inside this wall, surrounding, from above, the layer of matter that they cross "from above" to "below". This almost proud is called: almost proud in cyclone fluidized bed. The "main fan" draws gas around the axis of the quasi-cylindrical wall that is slotted, ie "below" the layer of material that is in cyclone fluidized suspension in the "gasification" space. carbonization-drying "and represses most of the gases that it has sucked, by a sheet metal shaped rotating machine scroll, in the chamber" gasification-carbonization-drying "in which it enters through the longitudinal slot of the quasi-cylindrical wall of this chamber, wall which is called internal wall of the reactor. Returned by the slot of this wall the gases spread on the inner face of this wall, which is closest to the axis. It is more inside the internal wall of the chamber that the layer of material moves, carried by the layer of gas spread on the wall It is the centripetal movement of the gas spread on the wall which makes the gas "Support" and fluidizes the layer of suspended matter, the centrifugal force due to the movement of the material, pushing the material through the gas that supports it. The gas, sucked by the main fan from the inner wall of the reactor to the axis of the reactor, therefore passes through the layer of material from "above" to "below". In this version it is only the remaining part of the gases blown by the main fan that passes into the "gas elevation at high temperature" space, advantageously located in the extension of the cyclonic "gasification-carbonization" space. -drying ", opposite the main fan.

Peripheral devices

Various devices that may be called peripherals are useful for the proper operation of the gasification devices implementing the carbonaceous material gasification process object of this patent. These are, for example: devices for taking up the material in an intermediate storage silo or in a long-term storage silo, dryers adapted to the characteristics of the material to be gasified, and to that of the calories that can be recovered on the entire installation implementing the carbonaceous material gasification process. It may also be material transport equipment: carpet, screw, elevator .... which intervene in the supply of the device material. After the exit of gases, several devices are useful or indispensable such as dust separator, gasification gas cooling exchanger which can, thanks to the calories it recovers warm up the gasification air when the gasification is made in the air but also a gasification gas scrubber cooled in the exchanger, and finally a series of devices that could be described as control, display and automation, as well as electrotechnical and electronic control and automation assemblies which drive the gasifier and the entire system in the center of which it is, manually or automated. Gas treatment

In all cases, the gasification gases leaving the "coal gasification" space usually contain dust. It is advantageous to separate these dusts from the gases before the passage of gases in the exchanger which heats the gasification air at the same time as it cools the gasification gases and the use of which greatly improves the efficiency of a gasifier. the air. This separation of dust, which takes place at high temperature is advantageously in a cyclone followed by multi cyclones. But it can also be done in a cone driven in rapid rotation. In all cases it is possible, after possibly passing through a dust separator and a heat exchanger, to pass the gases in a scrubber which has the advantage of treating or purifying them more completely and of being able to lower the temperature to temperatures slightly above atmospheric temperature.

Reheating gasification air

the improvement of the efficiency that can be obtained for an air gasifier by heating the gasification air (oxidant sent into the chamber of the "high temperature gas elevation" space makes it economically , in an air gasification process, the use of a countercurrent heat exchanger or an assembly of cross-flow heat exchangers, the heat exchanger used must withstand the high temperatures in order to heat up the heat. air to 600 ° from the heat recovered from the gasification gas, so it must be practically made of stainless metal alloy at high temperatures and must be very efficient and reasonably priced.

Gas scrubber

We have seen all the interest of having "clean pyroligneous" gases, which naturally gives the gasifiers according to the process. When it is desired to eliminate all traces of fine particles but also undesirable compounds other than pyroligneous, it is advantageous to carry out a washing of the gases.

This washing may also make it possible to recover a part of the latent heat of condensation of the water vapor contained in the gases.

Appliances such as air-cooled refrigerants can advantageously fulfill its functions of washer and heat recovery of low thermal level. But one can also use for gasification gas washing, other types of devices as effective more effective and less expensive, under development. Poor gas burner

In the case where it is desired to use gasification as the first step of a combustion, it will be possible to exit directly from the "elevation of the gases at high temperature" space the part of the gases which would be, in a standard gasifier, 'coal gasification' space. The gases that have come directly out of the "high temperature gas elevation" space will be sent directly through a highly insulated pipe to a device that could be called a "poor gas burner for a boiler", which will ensure combustion. gases coming directly from the "elevation of gases at high temperature" chamber by using the volume (and the wall which delimits it) reserved in the boiler, the burner and the burner flame. In this particular gasifier version implementing the method and devices of this patent, the gasification space of the coal has been eliminated. Such a special burner is part of the devices provided for implementing the method.

The gas intended for combustion in the boiler will advantageously be introduced by turning in the combustion chamber of the boiler where it will be burned by combustion air which will be introduced by a tube advantageously of decreasing square section, provided with fins of such that it is possible to introduce the tube provided with its fins by the hole usually for the burner of the boiler, and this, as it would introduce a conventional burner in the hole which is intended for it. The injection of air through this tube and fins will provide the flame with the necessary air for combustion and will turn the gases in the boiler combustion chamber vigorously enough for the combustion to be stable.

Depending on the quantity and the richness of the gases produced by the gasification, the quantity of air to be injected in the boiler burner will be defined so that the excess of air in the fumes leaving the boiler ensures sufficiently high CO contents. low in fumes.

SUMMARY DESCRIPTION OF THE DRAWINGS

The figures show various embodiments of the invention to which the invention is not limited.

FIG. 1 represents an overall perspective view of a gasifier according to the method, produced in a bed-laying version with a high-temperature elevation space separated from the "gasification-carbonization-drying" and "gasification" spaces; coal ".

Figure 2 shows a top view of the same set. Figure 3 shows a side view of this assembly.

FIG. 4 represents a section of the "gasification-carbonization-drying" spaces and the "gasification of coal" space.

Figure 5 shows a section of the grid in a particular embodiment.

Figure 6 shows a side view of the "elevation of high temperature gas" space in a particular embodiment.

Figure 7 shows a top view of the "high temperature elevation" space

FIG. 8 shows a section of a particular version of gasifier in which the "elevation of gases at high temperature" space is not separated from the "gasification-carbonization-drying" spaces and the space of " gasification of coal ".

Figures 9 and 10 show two perspective views of the same gasification system as Figure 8.

Fig. 11 is a perspective view of the interior of the "elevated gas elevation" space in the gasifier version shown in Figs. 8, 9 and 10.

Fig. 12 is a sectional view of the "high temperature gas elevation" space shown in perspective in Fig. 11.

Figure 13 is a sectional view of the "gasification-carbonization-drying" space of a cyclone fluidized cyclone version of a gasifier. FIG. 14 represents a perspective view of the same gasification device as FIG.

FIG. 15 represents a perspective view of a total combustion installation in which a fixed bed gasification system on a fixed gate supplies a boiler.

FIG. 16 represents a sectional view of a grid corresponding to the second device for driving the layer of material to gasify on the bed which supports it in the "carbonization-drying gasification" space and possibly in the space of 'Gasification coal which can prolong it. Note the "special inverted angles" (161), the returned angles "(162), the transverse plates (163), the longitudinal profiles (164), the material layer (165).

INDUSTRIAL APPLICATIONS

The first industrial applications of the invention are gasification, both products of very different grain sizes and humidities, systems integrating gasification and carbonization, simple combustion systems and / or incineration of many materials, systems electricity and heat cogeneration, electricity generation systems from biomass, heating systems with high environmental and energy performance from biomass (in particular wood chips or shredded wood, wet).

Claims

claims

1) a process for the gasification of carbonaceous materials taking place in a gasifier, which can be described by distinguishing various spaces: a "gasification-carbonization-drying" space, a "high temperature gas raising" space, and in some cases a "gasification of coal" space and / or a "finishing" space, characterized in that the material which advances in layer, since its entry into the gasifier, gradually changing at the same time as it advances, its carbon component being progressively transformed into gas and a mixture of ash and coal, is traversed transversely by the gas flowing in the gasifier and whose circulation through the layer of material, induces gasification.

2) Gasification process according to claim 1, characterized in that it uses a "means for moving the gas" in the gasifier to pass through the layer of material located in the space of "gasification-carbonization -drying ", then take it out of this layer and enter the space of" elevation of gases at high temperature ".

3) Process according to any one of claims 1 and 2 characterized in that the heat required for the elevation at high temperature of the gases that enter the space "elevation of the gases at high temperature" is provided, either by a partial combustion of the gases which are in this space, and which are a mixture of the partially burned gases which rotate in this space with the gases introduced into this space by the "gas-moving means" mentioned in claim 2 and with an oxidant which also enters this space, advantageously pushed by a fan and, as the case may be, heated or not by passing through an exchanger, either by at least one electric arc or by electrical resistors, or by a combination of these different means.

4) Carbonaceous material gasification process according to any one of claims 1 to 3 characterized in that a portion of the gases which are raised in temperature in the space of "elevation of the gases at high temperature", leaves the gasifier to be the object, after a short transport insulated pipe, a use that values the fact that they are at high temperature, for example a combustion in a "poor gas burner" boiler. 5) Process according to any one of claims 1 to 3 characterized in that a space, called "gasification of coal", extends the space of "gasification-carbonization-drying" and that the layer of material of the 'gasification-carbonization-drying' space is extended in the 'gasification of coal' space, and that it is the whole of the layer situated in these two spaces which receives the gases leaving the space of "elevation of gases at high temperature", by its face which will be called "above the layer". 6) A method according to claim 5 characterized in that in the space of "gasification of coal" the material layer is formed over its entire thickness of carbonized material mixed with ash and possibly inert.

7) A method according to claim 6 characterized in that, on the face of the material layer through which the gases exit, there is a material separation between the space of

'Gasification - carbonization - drying' and the 'gasification of coal' space, so that gases from the 'high temperature gas raising' space that passed through the portion of the layer layer that is located in the gasification space of the coal, which is constituted throughout its thickness of coal mixed with ashes and inert, out of the latter space and then gasifier without being mixed with other gases.

8) Process according to any one of the preceding claims characterized in that the coal and ash mixed with inert, which come out, in a layer, the space of "gasification-carbonization-drying" extended when there is one through the "coal gasification" space, enter the "finishing" space where, depending on the case, it cools and / or almost completely burns out of coal, then leaves the gasifier with a device that isolates internal spaces to the gasifier from the outside.

9) Process according to any one of the preceding claims, characterized in that it can treat very varied forms of carbonaceous materials: coke, coal, other fossil carbonaceous fuels, various forms of biomass at various relative humidities, various residues, products or, agricultural and agro-food and forestry by-products and maintenance of green spaces, various types of waste including wood of various classes, household refuse and industrial and tertiary waste and even, with the necessary precautions, hazardous carbon waste.

10) Process according to any one of the preceding claims, characterized in that the layer of material to be gasified is driven from its entry into the "gasification-carbonization-drying" space until its exit from the space of "Gasification-carbonization-drying", or until it leaves the "coal gasification" space where one exists, by means of driving the material which may advantageously be a set of "inverted angles" special "which slide successively and in an organized manner forward and backward on fixed grid, but can also be a thin piston that slides on a fixed grid, flowing between the fixed grid and the layer of material, these two advantageous techniques not excluding other techniques. 11) Process according to any one of the preceding claims, characterized in that the set of spaces defined in the gasifier is separated from the atmosphere by devices, which may advantageously be valves or double-valves, which limit the air in all the spaces of the gasifier during the introduction into the gasifier of the material to be gasified or during the extraction of the mixture of coal and ash supplemented by the inerts which were mixed with the carbonaceous material when introduced into the gasifier.

12) Apparatus implementing the process for the carbonaceous material gasification according to any one of the preceding claims, characterized in that in addition to the gasifier, it comprises at least one other device useful for its proper operation, for example: recovering the material in an intermediate storage silo or a long-term storage silo, dryer of the material to be gasified, transport device such as belt, screw, feed elevator, dust separator, gasifier gas cooling exchanger and reheating of the gasification air when the gasification is made in the air, the gasifier gas scrubber, the various sensors, the automation, control and display device, the electrotechnical control and automation assembly of the gasifier and the overall device.

13) Gasifier. Implementing the method of carbonaceous material gasification according to any one of the preceding claims, characterized by the fact that it has no space for "coal gasification" or "finishing space" That the "gasification-carbonization-drying" space is materially different and at least partially separated from the "high temperature gas elevation" space, the elevation of the high temperature gases occurring in a chamber cylindrical and being obtained by partial oxidation of the gases which rotate therein, entrained by the jets issuing from orifices situated in the trailing edge of aerodynamically-shaped fins introducing, by two joint channels forming a single fin, the fuel and the oxidant into the chamber, that the layer of material is driven by the movement of a flat piston or the organized displacements of a set of "special inverted angles" entails They slide over a grid formed essentially of turned angles, which a highly insulated pipe transports the hot gases leaving the "gasification-carbonization-drying" space to a device called "lean gas burners" installed in place. and instead of a conventional burner in the combustion chamber of a boiler, that the fumes coming out of the boiler are sent to an improved atmospheric refrigerant washer supplemented by a recycling device, before being discharged at low temperature into the atmosphere.

14) A gasifier, implementing the carbonaceous material gasification process according to any one of the preceding claims, characterized by the facts that:

- the "gasification of coal" space extends the space of "gasification-carbonization-drying",.

- the high temperature gas elevation chamber of the "high temperature gas elevation" space, the main fan, the grid and the device that advances the material onto the grid, the exhaust column into Coal of the mixture of ash and coal, the double-valves of entry and exit of material which isolate the space of the gasifier of the surrounding atmosphere, are all gathered in a same rigid mechanical assembly,

the gases leaving the gasifier pass through an exchanger and then into a scrubber before supplying a combustion engine.

15) A gasifier using the carbonaceous material gasification process according to any one of the preceding claims, characterized by the facts that:

the layer of material is not supported by material elements, but by the gases that enter tangentially through the longitudinal slot of the quasi-cylindrical inner wall of the reactor and rotate, along and inside this wall, surrounding, by the "top" the layer of matter that they cross "from above" to "below". This justifies calling this gasifier cyclic fluidized bed gasifier

the "main fan" draws the gases around the axis of the quasi-cylindrical wall split, that is to say "below" the layer of material which is in fluidized suspension cyclone in the space of "gasification -carbonisation-drying ", and represses most of the gases that it has sucked, by a sheet metal in the form of a rotating machine scroll, in the longitudinal slot of the quasi-cylindrical inner wall of the reactor in the inner wall of the chamber cylindrical, "above" the layer of material it keeps in suspension, the centrifugal gravity pushing the material in the box going from "below" to "above" the bed of material.

- in the extension of the "gasification-carbonization-drying" space, opposite the "main fan" is the space of "elevation of gases at high temperature" fed by the part of the gases pushed by the fan which is not returned in the quasi-cylinder split longitudinally of the quasi-cylindrical inner wall of the reactor.

- The high temperature gas elevation chamber also receives the oxidizer which partially burns the rotating gases in the high temperature gas elevation chamber. 16) A bedded gasifier using the carbonaceous material gasification process according to any preceding claim characterized by the facts that:

- the material is driven on the bed by the movement of a thin piston, moved on a grid by one or two tubes passing through the sealed wall of the gasifier by "tube passage" as tight as possible,

the tubes are actuated by devices placed outside the gasifier

- The piston is thin and circulates under the layer of material and the grid that carries this layer and the door too, him. 17) A bedded gasifier using the carbonaceous material gasification process according to any one of the preceding claims, characterized by the facts that:

- the material is dragged on the bed by the movement of "special reverse angles" receding one after the other, then advancing together

- the "special inverted angles" are based on a set of turned angles fixed on a frame and constitute with this frame the immobile part of the grid

- the "special inverse angles" are driven one by one or by group defined according to a defined program.

18) Gasifier using the carbonaceous material gasification process according to any one of the preceding claims, characterized in that:

- the "main fan" to operate at temperatures up to 800 ° C in a gas that contains dust and sometimes pyroligneous the fan is advantageously radial blade fan constructed of a metal such as refractory steel

- The axis of the "main fan" advantageously comprises one or more sections of "drop in temperature" which are advantageously welded assemblies of tubes and cones of thin sheet of refractory steel, filled with refractory wool, which join the wheel of fan to the rest of the shaft passing through the fan bearings

- The axis of the "main fan" is cooled in its part passing through the bearings. 19) A gasifier using the carbonaceous material gasification process according to any one of the preceding claims, characterized by the facts that

the gases of the partial combustion chamber of the "high temperature gas elevation" space rotate around the axis of the chamber at a high temperature and a high speed

- the partial combustion chamber of the "high temperature gas elevation" space is the place of a vigorous mixing between the rotating gases in the chamber, the fuel pushed into the chamber by the "main fan" and the oxidizer which is often air and is often pushed into the room by a fan the differential speeds of the gases of the chamber, of the fuel and of the oxidant at the places where the fuel is the oxidizer are injected into the chamber, are large enough that the mixture between these gases takes place in less than one revolution.

- The fuel and the oxidant are introduced into the chamber by ducts whose shape and arrangement are aerodynamic vis-à-vis the flow in the room. They come out of these conduits through holes in the leakage port of the ducts.

fuel and oxidant advantageously come out of these ducts in the form of a fin or an airplane wing, by orifices located in the trailing edge of these ducts or fins. The size of these orifices is defined so that the fuels and oxidant coming out of it transfer to the moving mixture a quantity of movement such that it compensates for pressure losses in the flow rotating in the chamber. and walls

the quantity of injected oxidant is regulated as a function of the temperature of the gases in the elevation chamber of the gases at high temperature.

20) Gasifier using the carbonaceous material gasification process according to any one of the preceding claims, characterized in that:

the gases of the "high temperature gas raising" chamber are reheated using an electric arc plasma or a set of electrical resistors arranged in the "high temperature gas raising" chamber or a combination of these two means.

- The desired high temperature of the gases is obtained by regulating the electric power of the heating device 21) Gasifier using the gasification process of carbonaceous materials according to any one of the preceding claims, characterized in that:

- in a first case, the mixture of coal, and ash supplemented by inerts, which leaves the space of "gasification carbonization drying" or "gasification of the coal" falls at the top of a column traversed against the current by a mixture of air and water vapor.

In another case, the mixture falls into a column whose two facing faces are semi-permeable and through which gases recycled by a fan. The recycled gases can be, if necessary, cooled by a sealed exchanger placed on the gas path

to reduce the coal content of the coal mixture without risking melting the ashes to which are added the inerts that were initially present in the material, the gas that is introduced into the "finishing" space is a mixture of air and water vapor advantageously obtained by bubbling the air into water at about 80 ° C.