1156 posts
Health and safety Question 1
We are having a 1.5Mt six-stage Precalciner kiln operating with South African coal having a VM of 28 per cent. Now we thinking to switch over to Indonesian coal with high VM content (up to 42 per cent) and Chinese coal (VM up to 32 per cent). The coal mill is a VRM having hot gases from cooler. Up to what maximum VM we can go without having explosion problems. With high VM coal what are the other changes to be carried out to regarding coal residue so that we do not get problems in the flame shape.
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1156 posts
Re: Health and safety
There are well established guidelines for the safety operation of coal grinding equipment. These fall into two broad categories:
(i) explosion prevention, and
(ii) explosion protection.
For prevention the best solution is to ensure that there is less than 12 per cent oxygen in the atmosphere. You cannot do that when cooler exhaust air is used for coal drying. As a general guideline drying with cooler exhaust air is suitable with direct firing systems. Other prevention measures are to ensure there are no fine coal dust accumulations in the system and no possible sources of ignition. These are determined by the design of the coal milling and storage system.
1156 posts
1156 posts
Re: Health and safety
Whether silicosis is a hazard of cement manufacturing depends on whether there is free silica in the raw materials. However, whether there is free silica or not workers should avoid breathing any dust into their lungs. Dust mask should be worn wherever there are high dust levels. There is no free silica in the cement final product.