Indirect Drying and Coking Characteristics of Coking Coal with Soda Residue Additive

Ze Zhang,Shuting Zhang

doi:10.3390/en14030575

Abstract

To improve indirect drying efficiency, the effect of soda residue on the drying characteristics of coking coal were studied using a self-made indirect drying system. A tube furnace was used in the dry distillation of coal samples with soda residue, and the coke properties were analyzed. The results indicated that the soda residue has a significant influence on the increase in the heating rate of coal samples in the temperature distribution range of 90 to 110 °C. With the addition of 2%, 5%, and 10% soda residue, the drying rates increased by 11.5%, 25.3%, and 37.3%, respectively at 110 °C. The results of dry distillation show that addition of 2%, 5% and 10% soda residue decreases the carbon loss quantity by 4.67, 4.99, and 8.82 g, respectively. The mechanical strength of coke samples satisfies the industrial conditions when the soda residue ratio ranges from 2% to 5%. Soda residue can improve the active point of coke dissolution reaction and inhibit coke internal solution. Economically, coking coal samples mixed with soda residue have an obvious energy saving advantage in the drying process. Energy saving analysis found that it can reduce cost input by 20% than that of the normal drying method.

Highlights

Characteristics of Coking Coal withIn the coking technology of drying, coal is pre-dried to reduce its moisture to less than6% before coking [1]
Indirect drying technology is the transfer of heat from a heat source to a medium, which may be heat-conducting oil, steam, or air
It is seen that the higher the temperature is, the shorter the drying time needed

Summary

Introduction

Characteristics of Coking Coal withIn the coking technology of drying, coal is pre-dried to reduce its moisture to less than6% before coking [1]. In the coking technology of drying, coal is pre-dried to reduce its moisture to less than. Many iron and steel enterprises have built and put into operation the coal moisture conditioning equipment and have independent intellectual property rights [3,4]. Indirect drying technology has some prominent problems, such as high energy consumption, dehydration, moisture reabsorption, and production of large amounts of dust. Indirect drying technology is the transfer of heat from a heat source to a medium, which may be heat-conducting oil, steam, or air. Indirect drying technology has many advantages: (1) no cross-contamination problem, because the material does not contact the heat transfer medium; (2) low heat loss and high thermal efficiency; and (3) equipment safety and low cost [7,8,9,10]. The development of indirect drying equipment has been paid much attention for a long time

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