Slag port pressure difference and syngas CO content
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I would like to ask everyone: recently, there has been a change in the type of coal used, resulting in a lower ash fusion point and less limestone being added. Additionally, we have observed fluctuations in the pressure difference at the slag outlet, along with changes in the liquid level of the gasifier. The CO content in the syngas has increased while the CO2 content has decreased. Could this be due to blockages at the slag outlet? Reducing the liquid level should help decrease the pressure difference.
As the liquid level drops, the resistance to gas flow through the liquid decreases, and the pressure difference changes. Generally, changes in the CO content are related to the furnace temperature; however, when the slag outlet is blocked, the CO content increases abnormally
The furnace temperature is probably too low. Large fluctuations in the slag port pressure difference are what lead to slag blockage.
On the forum, I read that if the slag outlet gets blocked, it affects the residence time of the gas. To be more specific, when the slag outlet is blocked, the jet region becomes shorter, which results in less carbon dioxide being produced. Meanwhile, the residence time in the pipe flow region increases, leading to a longer time for the reduction reaction to take place, and as a result, more carbon monoxide is generated. ”Is this certain?
The issue raised by the original poster is a typical case of fluctuations at the slag outlet caused by low operating temperatures; such fluctuations in the slag outlet lead to variations in composition and liquid level.
Increase in slag port pressure difference---------Smaller slag port------Increased reflux ratio-------The CO2 that returns upward reacts with coal powder to produce more CO
CO2 (already formed as a result of the reaction) + C (the unreacted portion in coal dust that will be converted into residual carbon in slag or ash) = 2CO. Is that correct?