OCR Text |
Show fV- 0 ...- Development of oxygen/COG combustion system for steel reheating Hideki Murakami, Masato Fujioka, Masataka Hase, Toshiaki Saito, Junichi Hayashi Heat-Auid Processing & Environment Research Center & Plant Engineering Division Nippon Steel Corporation ABSTRACT A new oxygen/COG combustion system for steel reheating is described. The purpose of this research is to develop a design technology of a compact reheating furnace using high enthalpy combustion of oxygen/COG burners. Experiments using 250McallHr. pure-oxygen/COG burner with steam blowing have been carried out, and a new oxygen/COO combustion system applying the divided supply of COG or oxygen, which can give better temperature unifonnity and lower NOx emission than the conventional one, has designed. Numerical simulations of a wide reheating furnace with oxygen/COO burners have been performed using three-dimensional unsteady mathematical model. The results suggest possibility of a compact reheating furnace using the oxygen/COG combustion. INTRODUCTION Recently, the global environmental problems associated with increasing energy consumption have been very serious, and an advanced industrial furnace, less energy consuming and less carbon-dioxide releasing, has been required. The authors have been concerned with development in design technology of a high-performance steel-slab reheating furnace. They believe that the application of oxygen/fuel combustion has capability for one of high-performance reheating furnaces, and have studied a new design of oxygen/fuel combustion furnace. The use of pure-oxygen/fuel combustion can result in several benefits, including very low CO2 emissions. However, due to the high flame temperature of conventional oxygen-fuel burners, these burners have not been employed in slab reheating furnaces but in only gas cutting or gas welding equipment It is because in slab reheating furnaces temperature uniformity is crucial for quality of steel products. In this paper, the researcQ works in design technology related to low height reheating furnace for combusting pure oxygen is described. Conducting three dimensional numerical analysis as well as laboratory scale experiment on the divided supply of oxygen or COG (Coke Oven Gas) with steam feeding from a main burner, the authors succeeded in obtaining expected realization for low height reheating furnace, enabling to achieve uniform reheating slabs and low NOx emission. OXYGEN COMBUSTION IN REHEATING FURNACE Generally, the use of oxygen/fuel combustion in a slab reheating furnace has the following advantages: First, large heat flux to a slab (efficient heat transfer) is obtained, due to higher temperature and larger emissivity of the flue gas in the furnace than in conventional ones. That suggests possibilities of a high productive and compact furnace. |