Excessively high CO content in the effective gas from Texaco gasification?
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I’ve recently noticed that the CO content in the effective gas is consistently high. It used to be normal at 45%, but now it can reach as high as 49%. I would appreciate some advice from those who know more about this
Is the ash content in coal relatively low?
Those on the first floor are doing the analysis, right? To answer your question, the occurrence of your issue when the furnace temperature is low indicates that you’re using a good quality coal. Generally, when the furnace temperature is low, the conversion rate is also low, and the composition of the effective syngas is high; in other words, the ash fusion point is high. When the furnace temperature is high, the ash fusion point is low. The choice of coal is very important – for example, refined coal results in a high gas production volume
The type of coal can be analyzed to adjust the furnace temperature accordingly.
It is recommended to conduct an analysis of the coal type, as well as calibrate the analyzer. It is unlikely that 49% will be achieved if there are no significant changes in the general operating conditions.
If there are no significant changes in the type of coal, check whether the slag outlet is showing signs of blockage; changes in the slag outlet can lead to a significant increase in CO levels.
Has the oxygen-coal ratio changed? If the oxygen-coal ratio is within the normal range, incomplete combustion may be caused by improper burner operation or blockages in the slag outlet ； Another possibility is that the online analyzer was not calibrated in a timely manner, resulting in higher analysis results. It is recommended that the instrument supplier use valid standard gases for regular calibration of online analyzers, so that the analysis results can accurately reflect the current production conditions!
Consider furnace temperature control, coal type, methane content
Why don’t you post your gas composition? With everyone offering so many suggestions, how are you going to consider them? I think it’s best to provide the information more comprehensively and in greater detail, so that other experts can take targeted action
When the slag outlet becomes clogged with slag, the exit resistance increases, mixing within the furnace increases, and some of the CO2 can continue to react with hydrogen and oxygen, resulting in an increase in the CO content
Does an increase in CO mean there is less oxygen, resulting in incomplete combustion? Of course, the furnace temperature also plays a role; haha, I don’t really understand it that well
Based on what the poster wrote, it is likely that the quality of the coal has improved; a lower ash melting point and higher carbon content have led to an increase in CO levels.
Whether the oxygen level is too low can be confirmed through the analysis of combustible materials in the ash; the content of combustible materials should be higher than before
One gas component is not enough to explain the issue. 1. If the process and other parameters are normal, then congratulations to you – the gas production rate has increased, which usually indicates that the medium is of better quality. Otherwise, it wouldn’t reach 49. There’s also an issue with the instruments, because it was only by using coal from Jincheng that we were able to reach 47 over the years. 2. Abnormal process parameters: changes in CO2 content and changes in methane content. Furnace temperature changes, furnace wall temperature. Changes in the oxygen-to-coal ratio, burner pressure difference, and gasifier pressure difference can all be considered for analysis.
Just saying CO really doesn’t help in understanding other influencing factors. I have a similar post that explains things clearly, yet people’s responses still fail to address the core issue. I suggest the original poster discuss other changes in the processes, such as the pressure difference at the slag outlet, changes in carbon dioxide and hydrogen levels, as well as factors like concentration and oxygen purity. Additionally, an analysis of the ash melting point should be conducted, performing tests from T1 to T4 to determine the temperature differences.
Please have the student on floor 16 share the materials: handshake
If, after stopping the machine, it is checked that neither the slag outlet nor the downcomer is blocked and the slurry concentration is normal. It is necessary to determine whether the ash fusion point of the coal slurry is high. Fluctuations in composition are generally detected by operators through online analysis. A high ash fusion point leads to high viscosity of coal ash, which causes it to get stuck at the slag outlet and not flow easily, resulting in uneven residence time of gas components and an increase in reverse transformation reactions. As a result, CO increases, CO2 decreases, and H2 decreases.
No special data is required; each furnace has its own characteristics. Sometimes it’s not the high ash fusion point that matters, but rather poor viscosity-temperature properties, meaning that the viscosity-temperature curve is not smooth. As a result, even if the ash fusion point is low, fluctuations in the ash content at the slag outlet can occur within a very narrow range of furnace temperatures, leading to compositional variations.
If the quality of the coal does not change and ash discharge occurs in the form of slag lumps, it indicates that the slag outlet or downcomer is blocked.