Ammonia production volume
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At present, our company uses coal briquettes for gas production; as a result, the composition of the gas has changed and the output volume is significantly low. We would appreciate your advice on this matter. The situation is as follows: 1. After using lump coal, the methane content in the gas reaches 4.4–5.6%, leading to high amounts of waste gas being produced and a decrease in output； Compared with factories that also use coal rods, analyses there show that methane content in semi-water gas is only around 2.1%. What’s the reason? Our semi-water gas contains about 10.5% carbon dioxide, about 27% carbon monoxide, and about 44% hydrogen. 2. In terms of coal briquette gas production at our company, compared with factories that also use coal rods, the difference lies in the height of the carbon layer; ours is higher. Could it be that this difference in carbon layer height is what causes the variation in methane content? 3. The slag from our gas generation furnaces can also be used, but the gas production volume is insufficient. Three 2800-model furnaces and three 2650-model furnaces are a bit inadequate to supply 14 machines with a demand of 36 m3/min. What is the reason for this? Thank you all in advance!
Based on the phenomenon described by the poster, it is mainly caused by a low temperature in the vaporization layer; when the temperature in this layer is low, the amount of gas produced decreases, while CO2 and methane levels increase. The thickness of the carbon layer does not affect gas production, nor does it have such a significant impact on methane. Also, is there a problem with the raw material used to make the coal sticks? Is its volatile content high?
Catalysts such as transformers and syngasifiers can produce methane, not necessarily semi-water gas! Once among us, it was caused by excessive side reactions of the methanol catalyst; also, what is the methane content in your hydrogen recovery gas? My suggestions are for reference only!
Coal rods are inferior to lump coal in terms of strength and fixed carbon content, and the resistance of the material layer formed by them is also significantly higher than that of lump coal. The addition of lignite also has a certain impact on the ash melting point of the coal. Therefore, when using coal rods for gas production, it is necessary to make corresponding adjustments to the gasification process taking these characteristics into account. Generally, in order to avoid problems such as the overturning of the material layer, it is necessary to reduce the load at the beginning of the adjustment process in order to explore the optimal conditions. The temperature in the gasification layer will be lower when using coal rods, so it is inevitable that the output per furnace will be lower compared to when using lump coal or small pieces of coal. Moreover, the composition of the gas produced is not as good as that obtained from lump coal or small pieces of coal. Good quality ash indicates that the gasification layer has been established properly, and the activity of the coal should be decent; the ash melting point of the coal is not very low either (our coal has a T2 value of only 1150, and a T4 value of no more than 1300). Additionally, the process engineers must be highly skilled. Of course, once exploration is done to a certain extent and the furnace is ready to handle higher loads, the load can be increased gradually; the volume and composition of the gas should improve. I wonder if you have any analysis data on the top-blown gas and the blowing gas, as well as data on the coal? Could you provide a bit more information?
Additional note: The ash content of the coal sticks is 23%, the volatile matter content is 9%, and the humic acid content is 3.5%