Optimization method for directional preparation technique and efficient use of semi-coke for blast furnace injection

A directional preparation technology of semi-coke for blast furnace injection, comprising performing dry distillation on raw coal to remove a portion of a volatile matter to prepare the semi-coke for blast furnace injection, and comprising the following steps:

• S11. according to a target value WAstandard of an ash percentage of target semi-coke, obtaining a relational expression between an ash removal percentage WAremoval in the raw coal and a volatile matter removal percentage WBremoval during dry distillation, as shown in Formula (1):
• W
• A
• removal
• =
• W
• A
• coal
• -
• W
• A
• standard
• (
• 1
• -
• W
• B
• removal
• )
• 1
• -
• W
• A
• standard
• (
• 1
• )
• in the formula, WAcoal represents a percentage of ash in the raw coal;
• the target value of the ash percentage meets WAstandard≤12%;
• S12. according to Formula (1) obtained in step S11, presetting a volatile matter removal percentage during dry distillation, wherein if the preset volatile matter removal percentage WBremoval meets Formula (2), the raw coal is first subjected to ash removal treatment before carbonization;
• if the preset volatile matter removal percentage WBremoval does not meet Formula (2), the raw coal is directly subjected to carbonization:
• W
• B
• removal
• ≥
• W
• A
• standard
• -
• W
• A
• coal
• W
• A
• standard
• ;
• (
• 2
• )
• wherein a method for determining a carbonization temperature of dry distillation comprises:
• based on the preset volatile matter removal percentage WBremoval, preliminarily determining a plurality of groups of carbonization temperatures and carbonization times of dry distillation through the pyrolysis behavior of dry distillation charring of the raw coal in a charring furnace, then, according to the plurality of groups of the carbonization temperatures and carbonization times, performing dry distillation and carbonization on the raw coal at different carbonization temperatures and carbonization times to prepare semi-coke, and respectively obtaining relationships between parameters comprising combustion rate, grindability index, explosibility index and jet flow index of the semi-coke and the carbonization temperature;
• wherein according to the relationship between the explosibility index and the carbonization temperature, selecting a carbonization temperature with an explosibility index≤200 mm as a lower limit value of the carbonization temperature, and then, in a temperature intervals higher than the lower limit value of the carbonization temperature, according to the relationships between the combustion rate, the grindability index and the jet flow index and the carbonization temperature, selecting a temperature interval in which the combustion rate ≥80%, the grindability index ≥60 and the jet flow index ≥70 as an actual carbonization temperature of dry distillation of the raw coal, and then selecting an actual carbonization time based on the actual carbonization temperature;
• S13. if the preset volatile matter removal percentage WBremoval meets Formula (2), first subjecting the raw coal to ash removal treatment, then performing dry distillation and carbonization at the actual carbonization time and the actual carbonization temperature determined in step S12, followed by cooling to obtain the semi-coke for blast furnace injection;
• if the preset volatile matter removal percentage WBremoval does not meet Formula (2), performing dry distillation and carbonization of the raw coal at the actual carbonization temperature and actual carbonization time determined in step S12, followed by cooling to obtain the semi-coke for blast furnace injection.