Method for preparing coal gas from molded coal

Abstract

The invention relates to a method for preparing coal gas by moulded coal, belonging to the coal gas industrial field. The technical problem solved by the invention is to provide a method for preparing coal gas by moulded coal under normal pressure. Moreover, the coal gas prepared by the method has higher heat value. The method is characterized in that: the thicknesses of material layers when moulded coal is gasified are: 300 to 500mm of an ash layer, 250 to 300mm of a gasification layer and 500 to 800mm of a fuel preparation layer; a gasification agent is obtained through mixing water vapor with air with oxygen volume content of 26 to 28 percent; and the saturation temperature of the gasification agent is between 65 and 67 DEG C. The heat value of the coal gas prepared by the method is between 6,300 and 6,700Kj/Nm<3> which is much higher than the heat value (approximately 5,200 to 5,500Kj/Nm<3>) of coal gas prepared by the prior method for preparing coal gas by moulded coal; therefore, the method has a wide application prospect.

Description

technical field [0001] The invention relates to a method for preparing coal gas from briquettes, and belongs to the field of gas industry. Background technique [0002] At present, most domestic chemical fertilizer, machinery, metallurgy, building materials and other industries, as well as enterprises that use fixed bed gasifiers to produce gas, use anthracite lump coal or coke as gasification raw materials. In the coal mining industry, with the improvement of the degree of mechanization, the output of anthracite pulverized coal (coal powder) is increasing, making the proportion of anthracite lump coal suitable for gasification lower and lower, and the contradiction between supply and demand of lump coal is becoming increasingly tense. Direct pulverized coal gasification requires a dedicated pulverized coal gasifier, and most companies currently use fixed-bed gasifiers for gas production. Therefore, it is necessary to prepare pulverized coal first and then gasify it in a fix...

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Problems solved by technology

[0004] The thickness ranges of the ash layer, gasification layer and fuel preparation layer during gasification of existing briquettes are: ash layer 200-300mm, gasification layer 150-200mm, fuel preparation layer 300-400mm, and the saturation temperature of the gasification agent is 52 -56°C (the air in the gasification agent used is ordinary air, that is, air with an oxygen volume content of about 21%), but because the briquette gasification (compared with lump coal gasification) is easy to pulverize in the generator, The resistance of the material layer in the furnace increases, the operating conditions in the furnace are unstable, and abnormal furnace conditions such as partial furnace, cold furnace or hot operation are prone to occur, and the calorific value of the prepared gas is low (about 5200-5500Kj / Nm 3 ), it is difficult to meet the requirements of enterprises

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