Method of adjusting ph value in production of coal-water slurry

Abstract

Abstract PURPOSE: To provide a method which can remarkably improve the accuracy of pH adjustment without bringing about rapid lowering in the pH value, enables prevention of corrosion of equipment constituting a low-concn. system, and can improve the quality of the title slurry, by adjusting the pH at two places, i.e., low and high concn. systems. CONSTITUTION: A method of adjusting the pH in the production of a coal-water slurry, wherein the pH value in adjusted in a low-concn. system, from an acid region, i.e., pH 4W6, to pH 7, i.e., a pH outside the range which brings about corrosion. The pH adjustment is conducted by detecting the pH value of the slurry with an on-line pH meter 20 provided in a slurry tank within a vacuum dehydrator 8 and feeding a pH adjustor to a wet tube mill 3 while adjusting the feed of the pH adjustor with a pH adjustor pump 17'. On the other hand, in a high-concn. system, the pH value is adjusted from pH 7 to pH 8W9. The pH adjustment is conducted by detecting the pH value of a high-concn. slurry discharged from a first slurry adjusting tank 10 with an on-line pH meter 19, adjusting the feed of the pH adjustor with a pH adjusting pump 17, and feeding the pH adjustor to a first slurry adjusting tank 10. In this method, corrosion can be prevented in the equipment constituting the high-concn. system as well as in the equipment constituting the low-concn. system. Further, the accuracy of the pH adjustment can be remarkably improved. COPYRIGHT: (C)1989,JPO&Japio

Inventors

• 👤 Toshihiko Imamoto

Bibliographic Details