The reporter learned yesterday from Henan Kaixiang Chemical Co., Ltd. that the device using the pulverized coal gasification-low water gas ratio and sulfur-tolerant shift process developed by Qingdao Lianxin Chemical Co., Ltd. has been successfully put into operation at Henan Kaixiang Company since July 1 So far, it has been running smoothly for more than a month, and the energy saving advantages are obvious, which proves that it is completely feasible for Shell's pulverized coal gasification process gas to use a low water-to-gas ratio conversion process for methanol production. This fills the international gap in the production of methanol from syngas with high carbon monoxide (CO) content under low water-to-gas ratio conversion process conditions, and opens up a new energy-saving and environmentally friendly way for pulverized coal gasification syngas with high carbon to hydrogen ratio.
It is understood that in the new process, the first reactor only needs to add a small amount of steam, and the second and third stages can meet the requirements for methanol production by quenching a small amount of water and increasing the water-gas ratio, and the transformation process is smooth. Methanation side reaction. Compared with the traditional high water-to-gas ratio conversion process, the new process can save at least 15 tons of steam per hour, and can also save a large amount of condensate water in subsequent sections. The device operates smoothly and has significant energy saving effects, so it is a very ideal high-efficiency energy-saving technology. A process for producing methanol from concentrated CO syngas. Following its successful application in the Guangxi Liuhua ammonia production unit last year, the low water-to-gas ratio sulfur-tolerant shift process was successfully applied to the methanol unit.
It is understood that the CO content in the feed gas produced by Shell's pulverized coal gasification process is as high as more than 60%, which not only increases the CO shift load of the sulfur-tolerant shift system, but may also cause highly exothermic methanation side reactions, causing the catalyst bed to The layer is overtemperature. In order to avoid methanation side reactions in the conversion section, most traditional designs use a high water-to-gas ratio conversion process. Although a high water-to-gas ratio can inhibit methanation side reactions, due to the high CO concentration and water-to-gas ratio, the reaction driving force is large. A slight change in the loading amount of the catalyst in one stage will significantly affect the reaction depth, making it difficult to control the bed temperature. .
According to reports, in other methanol units that were initially started using Shell's pulverized coal gasification process, over-temperature occurred in the first reactor due to low load or large catalyst filling margin. In order to reduce the reactor temperature, the water-gas ratio of the first reactor must be increased to above 2.0. This not only causes a huge waste of energy, but also because the first stage of the catalyst operates under harsh conditions of high water-to-gas ratio and high temperature, the catalyst will undergo reverse sulfurization, affecting normal production.
The 300,000-ton methanol plant of Henan Kaixiang Company, which uses Shell's pulverized coal gasification technology, was successfully started up in one go using the low water-gas shift process with the help of Qingdao Lianxin technicians, after adjusting the catalyst variety and making simple changes to the process flow. Produce qualified methanol.
