Coke production

Claim 1

A method of producing coke of low sulfur content, comprising grinding coking coal, drying and heating the ground coal at a temperature of 200° to 300° C. for 15 to 120 minutes by fluidizing the ground coal with gas thereby to produce a dried and heated material; passing said material to a first semicoking stage, heating said material by fluidization in said first semicoking stage at 300° l to 470° C. for 10 to 20 minutes while supplying to said first semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 10 to 30 normal liters per kilogram of dry coal, thereby to produce semicoke and first offgases; cooling said first offgases to produce condensed tar and first residual gases; recycling to said first semicoking stage as fluidizing gas 60 to 80% by volume of said first residual gases; passing the semicoke from said first semicoking stage to a second semicoking stage, heating the semicoke in said second semicoking stage at 400° to 600° C. for 10 to 20 minutes while supplying to said second semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 5 to 20 normal liters per kilogram of dry coal, thereby to produce semicoke and second offgases; cooling said second offgases to produce condensed tar and second residual gases; recycling to said second semicoking stage as fluidizing gas 60 to 80% by volume of said second residual gases; passing the semicoke from said second semicoking stage to a third semicoking stage, heating the semicoke by fluidization in said third semicoking stage at 800° to 1100° C. for 10 to 20 minutes with the production of third offgases while supplying to said third semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 40 to 100 normal liters per kilogram of dry coal; recycling to said third semicoking stage as fluidizing gas 10 to 20% by volume of said third offgases; and briquetting the semicoke from said third semicoking stage into formed coke.

Claim 2

A method of producing coke of low sulfur content, comprising grinding coking coal, drying and heating the ground coal at a temperature of 200° to 300° C. for 15 to 120 minutes by fluidizing the ground coal with gas thereby to produce a dried and heated material; passing said material to a first semicoking stage, heating said material by fluidization in said first semicoking stage at 300° l to 470° C. for 10 to 20 minutes while supplying to said first semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 10 to 30 normal liters per kilogram of dry coal, thereby to produce semicoke and first offgases; cooling said first offgases to produce condensed tar and first residual gases; recycling to said first semicoking stage as fluidizing gas 60 to 80% by volume of said first residual gases; passing the semicoke from said first semicoking stage to a second semicoking stage, heating the semicoke in said second semicoking stage at 400° to 600° C. for 10 to 20 minutes while supplying to said second semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 5 to 20 normal liters per kilogram of dry coal, thereby to produce semicoke and second offgases; cooling said second offgases to produce condensed tar and second residual gases; recycling to said second semicoking stage as fluidizing gas 60 to 80% by volume of said second residual gases; passing the semicoke from said second semicoking stage to a third semicoking stage, heating the semicoke by fluidization in said third semicoking stage at 800° to 1100° C. for 10 to 20 minutes with the production of third offgases while supplying to said third semicoking stage a make-up fluidizing gas containing oxygen in a quantity of 40 to 100 normal liters per kilogram of dry coal; recycling to said third semicoking stage as fluidizing gas 10 to 20% by volume of said third offgases; and briquetting the semicoke from said third semicoking stage into formed coke.