How to recover methanol from methanol tail gas
Thread Content
I would like to ask everyone, how to recover the methanol in the methanol exhaust gas? Nowadays, pressure swing adsorption can be used to separate and purify the hydrogen in the methanol relaxation gas. So how is the methanol recovered?
Our company also uses the same process, but does not recover the methanol in the vent gas. I don’t know how other units do it!
Nowadays, the method of washing with water is generally used, and the resulting dilute methanol solution is used as the extraction water of the methanol distillation pre-column.
In methanol cracking pressure swing adsorption hydrogen production and methanol production relief gas pressure swing adsorption hydrogen purification device, how is the reverse gas release/vacuum extraction of the pressure swing adsorption device handled? Should it be released directly, burned in a torch, or compressed and used for other purposes? How do each user unit do it? Welcome to release
The location of the methanol purge gas is generally selected after the methanol separator, and manufacturers generally use two-stage separation, namely mechanical separation and membrane separation. The methanol content in the gas phase after membrane separation is less than 0.6%. After being pressurized and mixed with fresh gas, it is still sent to the synthesis tower for synthesis; a small part is used as purge gas, and most of it is burned after hydrogen extraction. However, if the manufacturer also builds an ammonia synthesis device, it can be sent there directly. The best of both worlds.
At present, the most popular method in China and the most effective method is to install a special water washing tower after the methanol separator. The methanol gas content after the methanol separator is about 0.6 (medium pressure method), and the methanol gas content after the water washing tower is less than 0.1. In this way, there is basically no methanol gas in the purge gas. This technology has been applied in many methanol plants, and the effect is very obvious.
It can be used for membrane separation in methanol cracking pressure swing adsorption hydrogen production and methanol production relief gas pressure swing adsorption hydrogen purification devices.