The world's first conventional and double regenerative slab reheating furnace

Chenggang 1780mm hot rolling furnace is the first large slab reheating furnace awesome to be supplied by double regenerative burner and conventional burner in the world. Since its operation in 2008, its economic and social benefits have been remarkable, and its annual efficiency has been more than 90 million yuan, which has made green development of the power bearing steel.

In the iron and steel industry at home and abroad, the conventional combustion technology or regenerative combustion technology has been used alone in the walking slab reheating furnace. Facing the shortage of high calorific value mixed gas fuel supply, low recovery of low calorific value blast furnace gas and large emission, Chengde Steel decided to seek an efficient energy utilization technology to solve these problems in the construction of heating furnace of 1780 mm hot rolling coil production line.

Chenggang and Chongqing saidI Industrial Furnace Co., Ltd. jointly designed and developed blast furnace gas dual regenerative burner technology, which is applied to large walking slab reheating furnace. In the process of development and application, They listed the air gas nozzle spacing and intersection angle as the key dimensions of burner layout, studied the influence of air gas injection speed, nozzle distance and intersection angle on the flow field, temperature field and gas component distribution in the furnace, determined the better process parameters, and integrated the staged combustion technology into the domestic regenerative combustion technology. The air is divided into primary air and secondary air, which reduces local high temperature and improves the quality of combustion The temperature uniformity in the furnace is improved, and the generation and emission of NOx and other pollutants are reduced. The time sequence control commutation strategy is applied to alleviate the fluctuation of furnace pressure caused by valve reversing. By using the technology of natural smoke exhaust and forced smoke exhaust system, the difficult problem of furnace pressure control is effectively solved, and the common furnace door fire problem of regenerative heating furnace is solved. The combined heating technology of conventional and double regenerative was successfully applied in large slab reheating furnace, which further enhanced the research and application of regenerative combustion technology.

The technology of blast furnace gas dual regenerative burner is used in three reheating furnaces put into operation successively in 1780 mm production line of Chengde Iron and Steel Co. In the aspect of energy saving, the abundant low calorific value blast furnace gas in the plant area can be effectively utilized, the fuel waste caused by direct emission is solved, and the dependence on high calorific value coke oven gas is reduced. The fuel utilization rate of dual heat storage heating technology is 4.7% higher than that of conventional heating mode. The energy consumption index of heating furnace is reduced to below 32kg standard coal / ton steel, ranking the first among 17 domestic units in benchmarking. In terms of economic benefits, due to the reduction of energy consumption, 5.35 million yuan of fuel cost can be saved every year, and the recovery of low calorific value blast furnace gas can generate tens of millions of yuan of economic benefits every year.

The combined heating mode of dual regenerative burner and conventional burner of blast furnace gas not only realizes the application of low calorific value blast furnace gas in large walking beam furnace with high temperature of blast furnace, but also ensures the heating quality of slab. According to the current production situation, 1 billion m3 of blast furnace gas can be recycled every year, and about 400 million m3 of CO2 can be reduced. At the same time, it plays an important role in integrating the production structure of domestic iron and steel enterprises and optimizing the process flow. Under the environment of energetically advocating energy conservation and emission reduction, especially under the international background of greenhouse gas emission problem becoming increasingly prominent, blast furnace gas dual regenerative burner technology will have a broader application prospect because of its huge advantages in recycling low calorific value fuel and reducing exhaust gas emissions.