Fluidized-bed gasification reaction device with independent combustion chamber and fluidized-bed gasification reaction method

Abstract

The invention relates to a fluidized-bed gasification reaction device with an independent combustion chamber and a fluidized-bed gasification reaction method, belonging to the technical field of coal gasification. The fluidized-bed gasification reaction device mainly comprises a fluidized-bed gasification furnace and a combustion chamber which are separately arranged, wherein coal is gasified in the fluidized-bed gasification furnace, generated fly ash or bottom slag is subjected to high-temperature and oxidation treatment in the combustion chamber, so that the carbon conversion process is enhanced and the carbon conversion ratio is increased; the combustion chamber is at a higher operation temperature, the influence of high temperature on the fluidization state of the fluidized-bed gasification furnace can be eliminated just by simply treating high-temperature gas, entering the fluidized-bed gasification furnace, of the combustion chamber, and thus the fluidized-bed gasification furnace is easy to operate on the premise of ensuring high-efficiency conversion of the whole system. According to the fluidized-bed gasification reaction device and the fluidized-bed gasification reaction method have the advantages that the defect of low carbon conversion rate existing in the fluidized-bed gasification furnace is overcome, the environment is protected, the energy source utilization rate is increased and a wide application prospect is achieved.

Description

Technical field: [0001] The invention relates to a fluidized bed gasification reaction method and device with an independent combustion chamber, belonging to the field of coal gasification. Background technique: [0002] Fluidized bed gasification technology has a history of nearly 200 years. It has many advantages. For example, 0-10mm pulverized coal is usually used, and the raw coal can be used without or with a little treatment; a wide range of coal types can be used , especially coal with high ash and low quality; the gasification temperature is usually between 800-1000°C, and the conditions are relatively mild, and general refractory materials and equipment can be used; there is almost no tar in the gas, which is convenient for purification. Although it has the above-mentioned advantages that other gasifier types (such as fixed-bed and entrained-bed gasifiers) do not have, and has undergone a long period of optimization and transformation, there are still some existing ...

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Problems solved by technology

Although it has the above-mentioned advantages that other gasifier types (such as fixed-bed and entrained-bed gasifiers) do not have, and has undergone a long period of optimization and transformation, there are still some existing technologies in this gasifier that are difficult to overcome. Problems: First, the bottom slag has a high carbon content. Because the gasification environment requires reducing conditions, there is a large amount of unreacted carbon in the gasifier, and because of the good mixing in the fluidized bed, the bottom slag discharged by conventional technology High carbon content is inevitable. For this reason, more advanced fluidized beds (such as U-gas furnace, KRW furnace, ash fusion gasifier of Shanxi Coal Chemical Institute of Chinese Academy of Sciences, new fluidized bed gasifier of Academy of Coal Sciences) etc.) almost without exception, the ash mass (melting) aggregation technology is adopted. The basic idea of ​​this technology is to build a local oxidation and high temperature area in the gasifier to promote the transformation of carbon in this area and the softening of high temperature ash. And stick to each other to grow up, and then realize the selective slag discharge according to different densities. Practice has proved that this state is ideal, because the actual production conditions (raw material composition, oxidant, etc.) are difficult to keep consistent or synchronized to maintain coordinated changes, The fluctuation of ash composition affects the temperature of ash softening point, and the temperature range of ash softening is small. When the operating temperature is lower than the ash softening point, the purpose of ash mass (melting) aggregation and selective slagging cannot be achieved. When the operating temperature is higher than the ash softening point It is easy to cause a large amount of ash to agglomerate and cause the dead knot of the whole fluidized bed when the point is reached. For the sake of safety production, people usually choose a lower operating temperature, so the problem of high carbon content in the bottom slag has not been well solved; the second is The problem of high carbon content in fly ash, although the current process of collecting fly ash and recycling it back to the furnace, practice has proved that due to the low activity of this fly ash and the mild reaction conditions in the gasifier, the carbon in fly ash Not converting well

The existence of these problems leads to low carbon conversion rate, which greatly affects the industrial application of fluidized bed gasifier

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