The Simulation Of The Combustion Process For The Large-scale Ethylene Cracking Furnace

Oil refining industry is an important processing industry. Industrial boilers are the key facility for energy generation, industrial raw materials production and consumption. Because of its large wide using, industrial boiler plays an important role in many fields such as economic developing and good living environment creating. Low energy efficiency of traditional industrial boilers and emissions of nitrogen oxides and other harmful pollution seriously constraint the healthy and efficient industry development. Therefore, the careful study within the combustion boiler, material and energy transfer then take effective measures to reduce nitrogen oxides to improve energy efficiency are very important.Experimental study takes lots of money and time to build a large experimental device. Long period working and the lack of theoretical support made it very difficult. With the development of computer technology, computational fluid software are improved. Software can be studied using computational fluid flow combustion furnace energy transfer and emissions generated.In this paper, gas ethylene cracking furnace model using CFD-FLUENT GAMBIT pre-processor for processing into FLUENT to calculate. The furnace temperature field, velocity field, the main concentration of reactants and formation conditions and distribution of nitrogen oxides of the cracking furnace according to the actual operating conditions were calculated. From the calculated results and the literature results, the actual cracking furnace operating parameters be compared to the basic agreement. The result proved that the calculation using the mathematical model and use the various parameters are reasonable. The internal combustion chamber and fuel gas flow distribution and concentration of the components of nitrogen oxides were analyzed.This article refers to the clean-burning concept of internal combustion engine technology, the introduction of oxygen and exhaust gas recirculation, respectively. The fuel gas with different oxygen rates of heat release, fuel gas recirculation rate of different temperatures, different concentration of nitrogen oxides and the distribution of the main composition are calculated.The results show that the fuel gas recirculation can reduce NOx emissions, the fuel combustion temperature and fuel burn rate will be reduced. Oxygen-enriched combustion can increase the heat release of the furnace fuel combustion, but will increase emissions of nitrogen oxides in the boiler deterioration. The software CHEMKIN is used for chemical kinetic analysis of oxygen-enriched combustion heat of the combustion products and the CFD software is used to analyze the different rates of oxygen effect on NOx.According to the above results, combined effects of various aspects were considered to determine the appropriate rate and fuel gas recirculation rate of oxygen to make 6% improvement of the combustion efficiency of the ethylene cracking furnace and 14% reduction of the exhaust gas.?The?modeling?provided?a?basis?for?the?improvement?and?optimization?of?the?ethylene cracking furnace and other industrial gas boilers.