DE102011007808B3 - Reactor for gasification of ash-less or low-ash-fuel e.g. cold gas steam, in air flow carburetor, has cold gas chambers applied with cold gases such that cold gases flow through plate and porous material toward gasification chamber - Google Patents

Abstract

The reactor has a gasification chamber (7) limited in a pressure-bearing reactor pressure shell (4) by a porous reaction chamber wall (5). The wall is formed on a side with a perforated plate, where the side faces the shell, and a gas-permeable porous material is applied on the side facing the gasification chamber. Space between the shell and the wall in different horizontal planes in cold gas chambers (3.1, 3.2) is separated. The gas chambers are applied with cold gases (8.1, 8.2) such that the cold gases flow through the plate and the material toward the gasification chamber. An independent claim is also included for a method for operating a reactor.

Description

The invention relates to a reactor for the gasification of low-ash or ash-free fuels in the flow stream and a method for operating such a reactor.

The invention relates to a new technology for thermal insulation of the reactor, wherein low-ash or ashless fuels can be used. Such fuels are understood as meaning gaseous and liquid hydrocarbons such as natural gas, fractions of petroleum processing or by-products from syntheses, but also biomasses, coals and cokes whose ash contents are less than 0.5 mass.

The gasifier is a core component of the process of entrained flow gasification. The technology is described in detail in "The upgrading and conversion of coal" issued by the German Scientific Society of Petroleum, Natural Gas and Coal. V., Dec. 2008, chapter GSP gasification.

The gasification solid or liquid state are introduced via a gasification fuel burner in the reaction space of Flugstromvergasers and reacted with the addition of a free oxygen-containing gasification agent under pressures of up to 10 MPa and temperatures up to 1,900 ° C in a flame reaction to H2 and CO rich raw gas , The reaction space is spatially limited by the contour of the cooling screen and serves its thermal insulation. Ashes contained in the gasification material are melted in the flame reaction and settle on the inner wall of the cooling screen. The thus constructed and continuously renewed slag layer forms a Dämmmantel because of their poor heat conduction properties and limits in this way the heat flow to the cooling screen. The cooling screen itself consists of water-flown pipe coils. The recooling of the cooling water takes place outside the reactor. The decisive advantage of the described technology over the bricked-up alternative is the high availability with a long service life and the minimal thermal and material inertia of the system. This results in the extremely short time required for starting and stopping the carburettor as well as the insensitivity to fast load changes.

Different embodiments of the reactor wall show DE 20317461 U1 . DE 20 2007 018 717 U1 and DE 19643258 B4 , which are suitable for higher ash content of the fuels used. In the case of using fuels with no or only a small proportion of ash, the cooling screen technology has the disadvantage that due to the lack of or very thin and possibly not completely contour covering slag layer of the system, a large subset of the heat of reaction is withdrawn, bringing a reduction the process efficiency goes hand in hand. Furthermore, the thermal load of the cooling screen is increased so that damage and the reduction of the lifetime are the result.

From the US 7,736,600 B2 For example, a thermal reactor for removing residues from semiconductor manufacturing is known in which an internal porous wall encloses a central chamber. In the central chamber, a gaseous residue stream is introduced, which is decomposed by means of a thermal device and thereby forms reaction products. The porous wall, which is composed of a plurality of stacked sections may be enclosed by a perforated plate with a predetermined pattern of holes, wherein between the porous wall and the perforated plate at least one layer of a tile is arranged. The properties may vary within a portion of the porous wall. A system for supplying a fluid is configured to deliver the fluid with sufficient pressure through the porous wall into the central chamber to reduce deposition of the reaction products on the interior surface of the porous wall.

From the US 2010/0300063 A1 For example, a device for burning fuel at high pressures and temperatures or for producing synthesis gas is known in which the combustion chamber arranged in a pressure-bearing jacket is bounded by a wall. The wall has a porous layer towards the combustion chamber and a layer of steel with openings towards the jacket. The openings can via leads a transpiration fluid such. As CO2, are supplied with sufficient pressure so that the fluid passes through the porous layer in the combustion chamber.

The invention has for its object to replace the cooling screen technology for fuels with very little or no ash content by an efficiency-enhancing, alternative, while maintaining the high flexibility in the load cycling behavior of the carburetor.

The object is achieved by a reactor having the features of claim 1 and by a method for carrying out in such a reactor having the features of claim 16.

It is proposed to limit the gasification chamber by a wall consisting of a perforated plate coated with permeable porous material. A backwash of this arrangement with a gas, water vapor or a Combination of both at a slightly higher pressure level compared to the reaction chamber ensures a radially directed media flow from outside to inside. As a result, injection of the added gas / vapor into the flow boundary layer of the produced hot gas stream occurs. The flow of the gas / water vapor is thus directed counter to the heat flow from the reaction space to the outer wall of the reactor, heats up and cools the porous boundary wall. The heat flow to the outside is hindered, which leads to the limitation of the heat losses. The continuous addition of the cooling medium causes the wall to be maintained at a temperature level in the region of the cooling medium.

As a cooling medium, various gases such as carbon dioxide, self-produced synthesis gas, residual gases of subsequent syntheses, foreign gases such as natural gas or nitrogen can be used in addition to water vapor. Particularly interesting are water vapor and / or carbon dioxide, since these media also act as a gasifying agent and temperature moderator in the gasification process.

The cold room ( 3 ) between reactor pressure jacket ( 4 ) and reactor wall ( 5 ) is according to the invention in several superimposed and gas-tightly separated partial-cold rooms ( 3.1 . 3.2 ), the individual cold gas / water vapor pipe ( 8.1 . 8.2 ), separated. Partial cold rooms can be separated by a membrane ( 14 ) be separated.

At different heights of the reactor wall, different amounts of cold gas, which may also be present through a gasification agent, can be supplied from the cold space into the gasification space. This can be realized in general by different flow resistance of the reactor wall at different heights. The flow resistance of the reactor wall can be influenced by the thickness and porosity of the porous layer, number per area and diameter of the holes of the perforated plate.

In a further embodiment of the invention, various cold gases can be supplied. This applies on the one hand to the sequential supply of different cold gases, such as first nitrogen and then water vapor. On the other hand, this relates to the simultaneous supply of different cold gases, such as a mixture of nitrogen and water vapor. This also applies to the supply of different cold gases at different heights of the reactor wall.

The partial cold rooms can be subjected to different pressure. As a result, the amounts of Durchflußundierenden cold gases can be controlled individually at different heights of the reactor wall. This applies to both the same cold gas as well as different cold gas for different partial-cold rooms.

Advantageous embodiments are specified in the subclaims.

The invention is explained in more detail below as an exemplary embodiment in a scope necessary for understanding with reference to figures. Showing:

1 the overall representation of an entrained flow gasifier with porous reaction space wall ( 5 ) and several, separate cold gas spaces and

2 for details 1 the construction of the reaction space wall ( 5 ) and their position between reactor pressure jacket ( 4 ) and hot gas stream ( 1 ).

In the figures, like names denote like elements.

At the air stream carburetor after 1 the majority flows in a flame reaction, starting at the burner's mouth ( 6 ), formed raw gas ( 1 ) in the reaction space ( 7 ) downwards. Depending on the fuel / ash and desired product gas composition, temperatures of 1200 ° C to 1500 ° C prevail according to the equilibrium conditions to be set. By adding a cold gas over the cold gas nozzle ( 8th ) into the cold gas space ( 3 ) of the carburetor and when setting a corresponding pressure gradient between the cold gas space ( 3 ) and reaction space ( 7 ) it comes to the radially inwardly directed flow through the arrangement ( 5 ). The result is a cold gas film ( 2 ) on the inner wall of the reaction space, in the course of which there is the formation of a mixed phase of hot gas ( 1 ) and cold gas stream ( 2 ).

The supply of gasification agents, such as water vapor, as cold gas from the cold gas space ( 3 ) in the reaction space ( 7 ) takes place in an analogous manner. In this case, the injected fluid has a dual role as a cooling medium and gasification agent.

The raw gas produced ( 1 ) and the cold gas ( 2 ) and the mixed phase formed ( 1 ) and ( 2 ) are separated via the raw gas outlet ( 9 ) into the quench space ( 12 ), where there is a spontaneous cooling by direct water injection via the quench lances ( 10 ) learns. The quenched raw gas leaves via the raw gas outlet ( 13 ) the entrained flow gasifier. The cold room ( 3 ) between reactor pressure jacket ( 4 ) and reactor wall ( 5 ) is in two, generally a plurality of superimposed and gas-tightly separated partial-cold rooms ( 3.1 . 3.2 ), the individual cold gas / water vapor pipe ( 8.1 . 8.2 ), separated. The partial cold rooms are separated by a membrane ( 14 ), which can also be referred to as a diaphragm, separated.

In 2 is the structure of the reaction space wall ( 5 ) out 1 and its position between the reactor pressure jacket ( 4 ) and hot gas stream ( 1 ) shown in more detail. In the reaction space wall, the addition of the coolant is realized by a perforated corrugated tube perforated plate to which a porous material is applied. The space between the reaction space wall and the reactor pressure jacket is backwashed continuously with a cooling gas. The cooling gas penetrates through the holes of the perforated plate and the porous material into the reaction space ( 7 ). The perforated plate may have a vertically extending wave profile. Different levels of cooling gas can be injected at different heights of the reaction space wall. This can be realized by different flow resistance for the cooling gas. A membrane ( 14 ) separates the cold gas space into an upper cold gas space 3.1 and in a lower cold gas space 3.2 , The membrane can be given by a refractory material with interference fit.

LIST OF REFERENCE NUMBERS

1

raw gas stream

2

Coolants film

3

Cold gas space

4

Reactor pressure shell

5

porous wall

6

Gasification fuel burners

7

gasification chamber

8th

Cold gas / steam nozzle

9

Crude gas in the quenching room

10

Quenchlanzen

11

sealing system

12

quench

13

Rohgasaustritt

14

Diaphragm, diaphragm

Claims (18)

Reactor for the gasification of ash-free or low-ash fuels with a free-oxygen-containing gasification agent in the flow stream at temperatures up to 1500 ° C and pressures up to 10 MPa, in which - in the pressure-bearing reactor pressure jacket ( 4 ) the gasification room ( 7 ) through a wall ( 5 ) is limited, - the wall on the side facing the reactor pressure jacket is formed with a perforated plate, on the gasification chamber side facing a gas-permeable, porous material is applied, - the volume between the reactor pressure jacket and wall in different horizontal planes in a plurality of cold gas spaces ( 3.1 . 3.2 ), - the cold gas spaces with cold gas ( 8.1 . 8.2 ) are acted upon, such that the cold gas, the perforated plate and the porous material in the direction of the gasification space ( 7 ) flows through. Reactor according to claim 1, characterized in that the porous material of the wall ( 5 ) is divided into segments of different porosity in different horizontal planes. Reactor according to claim 1 or 2, characterized in that the porous material of the wall ( 5 ) has different material thickness in different horizontal planes. Reactor according to one of the preceding claims, characterized in that the perforated plate has different cross sections of the holes for supplying different amounts of cold gas at different heights. Reactor according to one of the preceding claims, characterized in that the perforated plate has a wave profile in the vertical direction. Reactor according to one of the preceding claims, characterized in that the cold gas spaces are separated by a membrane. Reactor according to claim 6, characterized in that the membrane is formed with a refractory material. Reactor according to claim 6 or 7, characterized in that the membrane has the property of interference fit. Reactor according to one of the preceding claims, characterized in that in the cold room ( 3 ) a drainage for accumulating condensate is arranged. Reactor according to one of the preceding claims, characterized in that the porous material of the wall ( 5 ) is divided into different horizontal planes for supplying different amounts of cold gas. Reactor according to one of the preceding claims, characterized in that the porous material of the wall ( 5 ) is subdivided into different horizontal levels for an individually regulated supply of cold gas. Reactor according to one of the preceding claims, characterized in that water vapor, carbon dioxide, self-produced synthesis gas, residual gases are used as the cold gas Syntheses or foreign gases, such as natural gas, individually or in any mixtures is given. Reactor according to one of the preceding claims, characterized in that steam and / or carbon dioxide are present simultaneously as cooling and gasification agents as cold gas. Reactor according to one of the preceding claims, characterized in that different gasification agents are present as the cold gas. Reactor according to one of the preceding claims, characterized in that different cold gas spaces ( 3.1 . 3.2 ) are acted upon with different gasification agents. Method for operating a reactor according to one of the preceding claims 1 to 15, characterized in that different cold gases are sequentially fed to a cold gas space ( 3.1 . 3.2 ). A method of operating a reactor according to claim 16 characterized by controlling the pressure of the supplied cold gas. Method for operating a reactor according to claim 16 or 17, characterized in that the pressure of the supplied cold gas is controlled individually for each cold gas space.

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