Study on Desulfurization of Coke Oven Gasby Diluted Ammonia Water (III)

Abstract

1, 000 Nm³/h pilot plant was designed and built at the coke plant site on the basis of industrial and technical knowledge obtained through the previous basic experiment for COG purification process by washing with diluted ammonia solution. Principal studies were conducted and discussed in the program, mainly on the absorption profile curve in a column, optimum flow combination for absorption liquid between two columns, ammonia addition rate to absorption liquid, and relation of residual density of H2S and HCN in absorption liquid with rate of gas absorption.
Past many attempts as Collin process and Coppers process were made to develop the removal of H₂S by means of thick ammonia solution with little success. H₂S removal in this work was conducted by means of diluted ammonia solution, because chemical absorption of H₂S in such solution was found to make good progress in parallel current flow which contributes to elevated Kca.
Factory waste free process is a final goal of development of COG purification by means of diluted ammonia solution washing. Removal rates of H2S and HCN are got over 98 % by means of regenerated lean solution, and over 90% for NH₃.