The carbon content issue in gas generator slag
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The issue of carbon content in the slag from gas generators: What is the typical carbon content in the slag produced by fixed-bed gas generators (3Aд13) and Endler-type gas generators? I heard from a fertilizer factory that the carbon content in their gas generation slag can reach 30%. How can the carbon content in the slag be reduced through process adjustments? Furthermore, can it be used in circulating fluidized bed boilers if it has a high carbon content?
The carbon content in the slag from our gas generation furnace is around 12%, and it can exceed 15% when the furnace operation is not optimal. We first sieve this slag; the larger pieces are sold directly, while the smaller fragments are used in mixed-fuel furnaces or fluidized-bed boilers for combustion, which works well, but a certain proportion must be maintained – too much of them won’t do; it should account for about 1/3. As for what the original poster said about the slag containing 30% carbon, that’s almost equivalent to low-quality bituminous coal. It’s fine to use it in fluidized bed boilers, but it results in excessive gas production costs.
Under normal conditions, the carbon content in the ash from fixed-bed gas generation furnaces is generally between 16-21%; when the operation of the furnace is not optimal, this value can reach 30% or even higher. Forums have indicated that the carbon content in ash resulting from oxygen-enriched oxidation is between 10-15%. Methods to reduce carbon content: 1. Control of coal quality, striving to ensure the coal is dry, free of ash, and has a uniform particle size. 2. Use superheated steam for gas production to increase the steam decomposition rate. 3. Optimize the process by making timely adjustments according to changes in coal quality, in order to stabilize furnace operation. 4. Adopt the operation principle of three highs and one low, and operate the gas generator at high load as much as possible. 5. Provide more blowing gas to ensure thorough vaporization of the carbon in the lower portion. 6. Advanced supporting equipment is used, such as high-air-volume fans and heat-wall jackets. 7. Strict management, and efforts should be made to standardize operating procedures.
Factors determining the carbon content in slag: 1. Conversion rate of fixed carbon； 2. Ash composition of the raw coal. Methods to reduce the carbon content in ash: 1. Use raw coal with a lower ash content ； 2. Increase the conversion rate of fixed carbon; each gasification method has a certain range for carbon conversion rates. To achieve a significant change, it’s necessary to switch to a different type of coal, haha – which isn’t cost-effective! ! !
There’s basically nothing that can be done; the gasification strength is just that high. Unless the gas production is reduced.