Let’s all discuss the operational status of converting coke oven gas into LNG or CNG
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Let’s all discuss the operational status of converting coke oven gas into LNG or CNG, and see which companies have reached their designed production capacity. Which companies have made any changes to their processes compared to the original design? Let me introduce myself first; I work at Hegang Zhengnan Coal Chemical, where LNG is produced from coke oven gas. The production capacity has not reached the designed level. As for the process, the furnace used for advanced desulfurization has not been taken out of service yet, as there isn’t enough heat from the catalyst to supply the heat required at the inlet of the pre-hydrogenation reactor. The startup furnace in the synthesis section has not been taken out either, due to insufficient heat exchange between the reactors. Why? Because I believe that the main constraint on the vast majority of processes is the shortage of feed gas! As for the shortage of feed gas, it is due to the supply and demand in the coke market.
Have the total sulfur tests for the bed outlet protection been passed?
Our factory is under construction; the factories that have been visited are operating at around 80% capacity. For both desulfurization and methanation, heating furnaces are used to compensate for the insufficient heat generated by the catalytic reactions. In the case of methanation, the H/C ratio of the gas feed is far from the desired value, which prevents the ideal amount of heat release during the reaction. Nevertheless, the operating company has not stopped the circulation gas compressor, possibly due to constraints related to the concentration of the final product. Experts continue to exchange ideas on this topic.
The heater in our methane chemical processing unit has not been turned on since it was put into operation. Heat exchange takes place
It is related to the hydrocarbon ratio; if the concentrations of CO and CO2 are high, it will cause intense reaction heat. In such cases, it is necessary to start the circulation pump and increase the circulation rate in order to lower the temperature. Otherwise, overheating can easily occur, leading to side reactions in the catalyst or even ignition. This circulation pump is an essential condition for operating the system.
You ask why the sulfur content at the exit of the bed is higher than that at the inlet? It has been confirmed – the test results are normal! The value is high, and this problem occurs especially when the sulfur level in the desulfurization section is not up to standard!
To summarize, for the conversion of coke oven gas into LNG, the first important factor is the catalysts. This includes the crude desulfurizing and degumming agents used before the reciprocating compressor, the iron-molybdenum and nickel-molybdenum catalysts used in the desulfurization process, as well as zinc oxide desulfurizing agents. The most crucial one is the catalyst used in the methanation reaction; it is essential to choose high-quality, reputable catalysts for this purpose. A company should not buy cheap items just to save a little money, as it will ultimately harm itself in the end. Think about it – we cry every time we remove the iron-molybdenum catalyst! ! !
Xindi replied that it was due to the ammonia content; following my suggestion, we moved it to below the protection bed. Basically, they are all qualified.
What has been changed to protect the lower part of the bed? Sampling tube? Or the position of the catalyst? If it’s the catalyst for this protection bed, there will be only one type of catalyst this time, rather than the two types used before.
Our protection bed consists of two catalysts, with three sampling ports: one in the middle, one at the bottom, and one at the outlet. PS: Are your protective beds made of zinc oxide or copper now?
The catalyst in the protection bed was replaced in September; this time there is only one type of catalyst, rather than the two types that were originally planned. The exact composition of the newly replaced catalyst is unknown, and the design institute will not disclose it.