DD145023A3 - PROCESS FOR GASIFICATION OF SOLID BREADS - Google Patents

Description

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Process for the gasification of solid fuels

Field of application of the invention

The invention relates to a process for the gasification of solid fuels by means of any suitable gasifying agent for the production of a fuel gas.

Characteristic of the known technical solutions It is known to gasify solid fuels with air, oxygen, steam or carbon dioxide individually or in mixtures with one another, thereby reacting the solid fuel in a fixed bed or in a fluidized bed or in an Elug cloud in the reactor with the gasification agent to let",

The specific gasification capacity, expressed in converted fuel per unit volume of the reactor, depends on the reactivity of the fuel, the reaction temperature and the mass and heat transfer in the heterogeneous phase. The influencing factors are related. The latter influencing factor is among other things of the relative speed between the. Gasification agent and the fuel as well as the surface of the solid fuel available for the reaction. «For this reason, gasification processes with decreasing grain size of the solid fuel

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higher specific gasification rates. However, the increasing grain size increases the floating speed of the solid fuel grains in the gasifying agent, thereby lowering the relative velocity between the gasifying agent and the fuel and leading to a decreasing tendency of the specific gasification performance. ·.

It is known that in order to achieve greater turbulence in the reactor and thus to increase the relative velocity between gasification agent and solid fuel, two or more jets of gasifying agent are directed against each other by solid fuel dust.

It is also known to achieve by pulsating supply of gasification agent and gasification agent in the gasification reactor, an increase in the relative velocity between the reacting media and thus to increase the specific gasification capacity.

In the known methods, additional measures are required to increase the relative speed between the gasification agent and the gasification agent, the effectiveness of which is physically limited or for which there are no technically realized solutions.

Pur the procedures that work with a very small grain diameter for the solid fuel is to achieve the necessary grain fineness before gasification a! Fine comminution with known grinding units, such as. As ball or vibratory mills required. It is generally known that in the case of fine grinding in vibrating mills, in addition to the comminution effect, chemical reactions can also occur between the ground products and the surrounding atmosphere.

The known methods require for high specific gasification services in addition to the gasification reactor plants for crushing, transport and intermediate storage of solid fuel; this tends easily in the necessary fine grain to deflagrations or explosions, so that special protective measures are necessary

Gasification processes, which operate with fine grain size of the solid fuel, are characterized by a relatively high content of dust-like constituents in the production gas at the outlet of the gasification reactor; these constituents must be removed from the gas by known means and devices and partly recycled to the reactor,

Object of the invention

The aim of the invention is to reduce the necessary for the gasification of solid fuel process stages while achieving a high specific gasification capacity and the reduction of the required process temperature ♦

DISCLOSURE OF THE INVENTION The object of the invention is to carry out the gasification of solid fuels in such a manner that a high specific gasification capacity is achieved at a reduced gasification temperature and the devices and protective measures for the transport and intermediate storage of the fine-grained gasification solid fuels are no longer needed »

It was found _? that in comminution of the solid fuel in vibrating mills, the surfaces, the comminuted material and the Bex \ movement of this good

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favorable conditions for achieving high specific gasification services. Due to the mechano-chemical processes in vibratory grinding, radical formation may increase the reactivity of the solid fuel, with certain mineral constituents of the coals in addition to catalyzing effects. For this reason, the gasification reaction is directly superimposed on the comminution process, i. the gasification agent is fed directly to the grinding unit; the grinding room of the vibrating mill is simultaneously transformed and used as a gasification reactor »

Furthermore, it has been found that it is possible to carry out the grinding media of the vibratory mill in a suitable manner, together with possible residues, continuously from the mill, to be thermally treated in a separate device and enter again in the hot state as a heat carrier in the grinding gasification reactor.

It has also been found that in the grinding chamber of the vibrating mill can be achieved by suitable rinsing or gasification agent, a pre-reaction of the coal during the milling process and the coal pretreated directly to a downstream gasification reactor, for. B. a vibration tube, is supplied. By pretreating the coal, the material fed to the gasification reactor has a higher reactivity than normal coal and thus gives a higher specific gasification performance. "

It has also been found that in the gasification in a vibrating mill, compared with all other dust gasification, a countercurrent flow of the gasification agent to the coal stream, can be performed? Thus, an effective utilization of the sensible heat of the production gas to the thermal

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With the aid of the method according to the invention, gasification plants can be constructed and operated with fewer process steps and less effort. The increase in reactivity arising under mechano-chemical action permits according to the invention the progress of the gasification reaction at reduced temperatures. This results in advantages in terms of the specific need for oxygen and steam. The reduced danger of slagging leads to a stabilized process and relieves the problem of generator lining «

The use of solid fuels with easily melting or volatile ash constituents is possible. The high specific gasification capacities achievable according to the invention, combined with the reduction of the process stages, enable small aggregate and plant dimensions. When using the circulation of the grinding media as a heat transfer medium, the oxygen and / or air which is otherwise necessary for maintaining the process temperature can be reduced, which, when air is used, leads to a considerable reduction in the inert gas content of the gasification gas.

embodiments

The invention will be explained in more detail below on three exemplary embodiments »

1 _β Binned lignite grit ο -Ίο mm having a water content of 25 i <> and an ash content of 1o $ by means of known devices continuously one of: the additional gasification furnished vibration mill supplied during the Mahlprosesses, at a temperature of 65o 75o ⁰ C runs, takes place, preferably the finest

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Korn, the gasification reaction between the coal and the gasification agent, which is fed by a suitable device in the grinding chamber. The resulting gas leaves the grinding chamber via a. corresponding device. Non-gasified coarse grain remains in the mill and is still subject to the grinding and gasification process. Immediately after exiting the mill, the gas is subjected to normal further processing.

2. Coal, according to the embodiment 1, is continuously fed by means of known devices provided for the additional gasification and for a heat transfer medium vibrating mill The milling and gasification processes run as in the embodiment 1, also the outlet and further processing of the gas generated. The mill is equipped with an additional suitable discharge device for the continuous removal of a grinding media stream. The media stream contains an adjustable proportion of coal and enters a continuous combustion reactor in which the coal fraction is burned by air supply and thereby heats the media. The heated grinding media are separated from the coal ash by suitable means and returned to the mill as a heat carrier in the hot state,

3 »coal, according to the embodiment 1, is also the embodiment 1 corresponding end, supplied to a furnished for additional thermo-chemical treatment vibrating mill, by

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Supplying a purge gas, consisting of hot production gas, the coal is dried during the grinding and. As far as degassed that arise from the resulting semi-coke no liquid hydrocarbons in the course of subsequent gasification in a fluidized bed reactor. The fluidized-bed reactor is connected directly to the semi-coke discharge of the vibrating mill and is fed with the hot semi-coke. The gasification takes place with water vapor and a small amount of air to maintain the gasification temperature. The purge gas separated from the vibratory mill contains the moisture and the carbonization products of the coal. "The purge gas and the gasification gas can be processed separately or together

Claims (4)

Claim for invention # ' 1. A process for the gasification of solid fuels by means of suitable, any gasification agent, characterized in that the gasification in the grinding chamber of a vibratory mill runs directly during the grinding process. 2 _# Method according to item 1, characterized in that by a separate device, the grinding media continuously discharged from the mill, thermally treated and fed back to the mill as a heat carrier " 3. The method according to item 1 and item 2, characterized in that run in the grinding chamber of a vibrating mill instead of a residue-free gasification pre-reactions of the solid fuel with suitable rinsing or gasifying agents and the solid fuel thus treated is completely vergvergung in a downstream gasification reactor. 4. The method according to item 1, 2 and 3, characterized in that the gasification agent is passed either in cocurrent or in countercurrent with the coal through the Mahlvergasungsaggregat.