Under the condition that a power station could be set up in Miike -Where was the largest coal field in Japan-for the purpose of consuming the coal of Mitsui Mining Co. Ltd., Miike, Mitsui Aluminium Co. Ltd. have begun to smelt aluminium which required much electric energy.
Originally, because of contenting high sulfur and low melting point ash, the coal in Miike was criticized to be difficult to consume for boiler.
Accordingly, we had to solve the difficulty how to boil the low quality and high sulfur coal without raising clinker trouble and how to restrain to exhaust sulfur to the atmosphere.
Consequently the various investigations and scientific researches, and on top of that, running the pilot plant scaled 1/200 for a long time-many experiences and investigations of operating condition could be obtained during this test-we finally established this wet type sulfur removal process used carbide sludges in large capacity for coal fired power boiler-156MW scalr-for the first time in the world.
The distinctive feateres of this process are as follows:
1. Be possible to applicate reasonably in the limited space.
2. Low cost of construction and running.
3. Simple process and construction.
4. No secondary harm by-product and be able to retire it for plaster.
5. The absorbefacient Ca (OH) 2 can be gotten cheaply and stably.
6. High efficiency in removing sulfur and dust, and in operating continuously.
7. Stability against the variation of boiler load and sulfur content in the coal.
8. Suffieiently shut out bloaking by plaster scale which is criticized very difficult to keep away in wet process.
Fortunately our commercial plant is favorably running without trouble ever since starting up -March 1972- and the efficiency is high beyond of the original plan.
With this success in our undertaking, the coal in Miike could be consumed continuously in large quantities.