Author has introduced the technical features and the present technical progress of purification process of low temperature methanol washing;the comparison has been made for this process with the process technologies of tannin extract de-sulfur adding Benfield de-sulfur and NHD process technology from aspects of energy consume,equipment,process etc.

The low temperature methanol cleaning process has characteristics of good selectivity and high degree of purification, and strong absorption,low energy consumption and operating costs,comparing with other acidic gas purification process.

The paper presents the transformation of the original 1 000 mm and 800 mm synthesis ammonia plant, replacing the cuprammonia liquid purification process with the advanced full autothermic non-constant pressure methanolizing-methanation process.

Presently the environmental impacts of incineration flue gas scrubbing technologies are evaluated mainly by the emission standards,and when all of them can meet up with the emission limits they are difficult to be compared and to establish the order of priority.