Study On Technology Of Pulverized Coal Injection In Blast Furnace At Bayi Iron & Steel Co.

Xinjiang is rich in coal resources. Most of coal is developed in near geological age. The coal has low carbonization, high volatility and high explosion ability. Anshan Iron and Steel Corporation's successful experiment of injecting bitumite is a technological breakthrough in our country. But it can only solve the problems on safety and technology for low and middle volatile bitumite, the problems on high volatile and explosive bitumite in Xinjiang have not been solved yet. Therefore, the study on making use of high volatile bitumite is very important, and is also significant for solving thoroughly the techniques of injecting bitumite in blast furnace in our country.On the basis of the multi-purpose of the coal which is injected in blast furnace, the coal mines around Bayi Iron and Steel Co. were sampled and pre-chosen in this study, the samples were tested on physical and chemical properties. The explosive property was particularly checked. The results proved that the explosion ability could be restrained by means of suitable mixing of multi-coal, especially, the mixing of firing coal and bitumite. The explosion restraining effect of three kinds of bitumite mixture was better than that of two kinds. The bigger the difference between two kinds of coal, the more obvious the explosion restraining effect.After injection coal, the distribution of gas flow and ratio of heat flows inside the blast furnace will change. Some measures should be taken to ensure the stability of the furnace. The different change laws in blast furnace were achieved when the ratio was increased. After injection, the theoretical burning temperature decreases at tuyere. Heat compensation must be carried out to maintain the proper temperature zone. The studyshowed that the theoretical burning temperature which suitable for blast furnace was concerned with the kinds of coal used. The low limit of the theoretical temperature for bitumite injection was lower than that of anthracite injection because the bitumite had good combustibility and the uncombustible pulverized coal was easily digested inside the furnace.The kinds of coal and technical equipments used for blast furnace mjection should be based on the situations of each steel company and the synthetic characters of blast furnace coal injection to achieve the best economic efficiency. The optimized study proved that Bayi Iron & Steel Co. achieving the best choice by using 90% bitumite and 10% firing coal. However, Bayi Iron and steel Co. should use more than two kinds of bitumite because the firing coal resources was limited.Bayi Iron and Steel Co. has employed the techniques such as coal proportioning, appropriate adjustment measures and the optimum equipment for coal injection and achieved the high coal injection ratio of 150kg/t.Fe. The practice indicated that the technique was advanced, practical and at the top position in China.