What is the dust content at the inlet of the ceramic filter in a Shell furnace?
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What is the designed dust content at the inlet of the ceramic filter in a Shell furnace? If it is too high, what impact does it have on the filtering efficiency of the ceramic filter?
If the furnace can handle the ash content of the coal powder, then the ash handling system can handle it as well. If it is too high, it only affects the time for ash to settle. Or by changing the backflow frequency, the ceramic filter can be protected.
The design of Shell’s dry ash removal system is related to both the gas flow rate and the quality of the coal. When the gas flow rate and the amount of ash reach certain levels, it becomes difficult to meet the requirements using only ceramic HPHT units; therefore, a cyclone separator needs to be installed in advance.
Reply: 1. The HPHT ceramic filter is designed based on the type of coal, taking into account factors such as the treatment load and inlet concentration, while maintaining a certain margin (usually 20%) to cope with deteriorating raw material quality or increased gasifier load. 2. Regarding the indicator for dust content at the inlet, there are no very clear requirements specified in SHELL’s materials; the key lies in maintaining stability in the coal type. 3. An excessively high dust concentration at the inlet or an excessive load will increase the frequency of filter backwashing; in severe cases, it will lead to an increase in pressure difference, which inevitably affects the service life of the filter elements.
Based on the available information, the dust content in the syngas exiting the gasification furnace of a SHELL furnace is approximately 50% of the total amount; if it goes directly into a ceramic dust collector, it should be this same level
There might be an error in the order of magnitude? When it reaches 50%, it seems to indicate powder transport in a dilute phase. The estimated proportion of ash dust in the syngas should be between 3% and 8%; under normal operating conditions (e.g., around 70%), the normal value is approximately 5%. It is highly related to the load and coal quality.
I’m sorry, I didn’t explain it clearly. 50% refers to half of the dust content in the gas after it exits the vaporization chamber, not half of the syngas
In the design of the SHEEL gasifier, the ratio of slag to fly ash is 70%:30%. These are the design requirements it is intended to meet. The fly ash content at the inlet of unit 1500 can be calculated by multiplying the amount of coal consumed per hour by the ash content, and then by 30%
Xiangyun Tianhua and others use lignite, which has a high ash content; a cyclone separator is installed at the outlet of the gasifier cooler to remove some of the fly ash before it enters the HPHT filter. Under normal operating conditions, the fly ash content is related to the coal quality
In Texaco’s quenching process, the ratio of slag to ash is approximately 80%:20%, and this is the ratio after the water bath; Shell’s dry coal powder process probably does not reach such a high ratio of 7:3
Could someone from Shell tell us what the current ash ratio is approximately?