Weekly Question: What are the reasons for high levels of trace gases in the fresh gas? How to deal with it?

In cases where copper washing is used, the problem usually lies in unstable operation of the copper washing unit, or insufficient gas displacement during the process of introducing air into the high-pressure system; as a result, some of the gas in the pipelines is sent directly to the synthesis system without going through the copper washing process. In systems that use co-alkolization, the instability in methanol processing leads to an excessive amount of CO, exceeding the capacity of the copper washing unit. In systems that use low-temperature washing, either the circulation rate of methanol is too low, or the methanol temperature is not within the optimal range, or the high water content in the methanol reduces its absorption efficiency

For Kellogg’s process, regarding trace amounts of CO + CO2: 1. The decarburization capacity is insufficient, resulting in a high CO2 content in the outlet gas; address this by dealing with the underlying causes. 2. The conversion capacity has declined, leading to a high CO content in the outlet gas; check the catalyst activity and adjust the water vapor ratio. 3. The methanation capacity has decreased, causing a high CO/CO2 ratio in the outlet gas; increase the methanation temperature appropriately and check the catalyst activity

Reply to 1# 654262293 1: Slight increase in copper washing amount； 2. Internal leakage in the compressor direct-through valve ； 3. Internal leakage in the heating line valve for diol ；

Additional note: Internal leakage of the equipment, in case there is heat exchange between the process gas before decarburization (or shift) and the process gas before methanation.

Dual-methane process: Methanol migrating to methane; high levels of CO and CO2 lead to an excessive methanation load. Identify the cause and reduce the levels of CO and CO2. The instrument readings are incorrect; perform calibration of the instruments. The methanation temperature is too low; increase it appropriately

The last edit to this post was made by 654262293 on 2011-1-18 08:13. Regarding the trace amounts of CO and CO2 in Kellogg’s process: 1. The purified gas at the decarburization outlet has a high CO2 content, while the gas at the shift reactor outlet has a high CO content. 2. The CO/CO2 ratio at the methanation outlet is high. 3. There is leakage in the heat exchanger between the methanation outlet and the inlet gas

Everyone has analyzed it more or less the same way. top down

They’re more or less the same; when washed with liquid nitrogen, the ammonia purity remains very high

I’ve encountered situations where internal leakage in the methylene section (of the purified gas and methanated gas) caused blockages due to cold crystallization of diammonia

1. The decarburization capacity is insufficient, resulting in a high CO2 content in the exported purified gas. 2. The transformation capacity declines and the CO content at the outlet is high; adjust the water vapor ratio. 3. The methanation capacity is reduced, resulting in high CO/CO2 levels at the outlet; the methanation temperature is too low, so it should be increased appropriately. The levels of dimethyl are high, while the amount of methanation is low, resulting in an excessive load; identify the cause and reduce these levels! 4. In cases where copper washing is used, the problem mainly lies in an unstable operation of the copper washing process, or insufficient replacement of gases during the air introduction process by the high-pressure machine; as a result, some of the gases in the pipelines are sent directly to the synthesis stage without going through copper washing. G, g0 W8 A# U; s: h7 r7 ~% T: K 5. The operation of methanol synthesis is unstable due to an excessive amount of CO remaining, which exceeds the handling capacity of the copper washing process. 6. If a low washing level is observed, it is either because the methanol circulation rate is low, or the methanol temperature is not within the optimal range, or the high water content in the methanol results in poor absorption efficiency. 7. Internal leakage in the compressor direct-through valve, and internal leakage in the alcohol blending temperature rise line valve. 8. The instrument display is incorrect; check the instrument. 9. It is necessary to check whether the synthetic catalyst has lost its activity or is temporarily poisoned; increase the methane level and take appropriate measures to restore its activity!