[Weekly Topic] May 21-27, 2011

Nitrogen is introduced to desorb carbon dioxide from methanol at as low a temperature as possible. The amount of nitrogen used in gas stripping should be as high as possible within a certain limit; however, too high an amount increases nitrogen consumption, while too low an amount increases the load on the regeneration tower. The inlet pipe is designed in an inverted “U” shape to prevent methanol liquid from flowing back into the nitrogen stripping line.

①Control of the water content in the solution is important; methanol solutions contain large amounts of acidic gases such as hydrogen sulfide and carbon dioxide. When these substances dissolve in water, they cause electrolytic corrosion. Especially in regeneration towers where the temperature is high, when the water content is 1–2%, the level of impurities in the solution increases significantly. When the water content exceeds 5%, the methanol’s absorption capacity declines, the system operates at half capacity, and this can lead to blockages in the coil-type heat exchangers in a short period of time. ②Enhance solution filtration; catalyst powder brought in from previous stages, as well as impurities such as FeS generated during system operation, can cause blockages in the heat exchangers, so it is necessary to improve the cleaning of the filters.

Reply to 1# sxtblo: I really don’t know how to answer this question; this reply is meant solely for learning purposes, please understand!

The purpose of nitrogen filling is to remove oxygen from the heat exchanger, preventing the formation of loose iron oxide during operation, which could otherwise clog the equipment. The above are merely my guesses; please feel free to correct me