Engineering Application Study On Tubular Furnace COG Blended BFG

There are many different kinds of low calorific value gas in our country. However, it has long been considered that most of "off-gas" is discharged in vain, not only pollute the environment, but also a waste of energy, also brought a series of social problems. Some of the low calorific gas value generated in the steel, chemical and other industries. As China’s energy shortage and environmental requirements are increasingly stringent, the use of low calorie gas as the main part of the fuel or tubular heater has been generalized in the country. But low calorie gas has a lot of problems in the country to promote the application, such as low heat, combustion instability, so the research of doing the tubular heater using low calorific value gas replacement or blending is particularly important.Based on such background, this article is a study on feasibility of the HTF tubular heating furnace using COG blending BFG. Original tube furnace uses a heating value of 4186 kcal / Nm3 of COG, in order to achieve the goal of energy saving and environmental protection, and now we need to transform the use of COG mixed with heating value 793 kcal / Nm3 blast furnace gas. For this project live, this article analyzes the characteristics and combustion conditions of low calorific value gas, especially BFG. It also analyzes NOx formation mechanism of low calorific value gas. This transformation program using COG mixed with BFG, mainly analyzes the thermodynamic calculation of blending, the combustion system design, control logic, process systems, energy efficiency and other aspects. Using numerical simulation method to simulate the different blending proportions of the furnace operating conditions, calculated the velocity field, temperature field, NOx content of using 20% COG, 50%COG, 80% COG, analyzed and compared to optimize the combustion system.Because of the low calorific value of BFG, in order to reach the required heat load, the volume of BFG needs to increase a lot. And the flame height is easier to exit leading gas temperature increasing and reducing furnace efficiency. So the use of the installation of sunken adiabatic combustion chamber and combustion of the intermediate chamber are provided for the steady flame low calorific value of blast furnace gas column to promote stable complete combustion. A pillar is provided in the intermediate of combustor to make the flame of the low calorific value gas--BFG steady and ensure stable and complete combustion.