Ammonia Oxygen-enriched Combustion Experiment And Mechanism Analysis

With the proposal of carbon neutralization target,ammonia as a secondary energy source is expected to solve the problem of hydrogen energy storage and transportation.As a non carbon gas,ammonia can be used as fuel for combustion.In theory,the products of ammonia combustion are only water and nitrogen,which is a new kind of carbon free fuel.Compared with hydrogen without carbon element,ammonia combustion is more gentle and convenient for storage;However,there are many problems in the actual combustion of ammonia.Ammonia combustion is not as stable as alkane fuel,and there are a lot of fuel NOx in combustion flue gas.These factors limit the practical application of ammonia as fuel.In this paper,the idea of increasing the concentration of combustion supporting oxygen to improve the combustion stability of ammonia is put forward.Through the combination of experiment and numerical simulation,the combustion characteristics of ammonia and NOx generation law under oxygen enriched conditions were studied.The sensitivity and path analysis were carried out,and the recommended application parameters for collaborative optimization of reaction rate and NOx emission were obtained.Firstly,the NOx content in the flue gas of ammonia oxygen enriched combustion was measured by Bunsen burner test-bed and MRU instrument.By changing the oxygen concentration and combustion equivalence ratio,the NOx law under different conditions is obtained.The sensitivity analysis module in CHEMKIN is used to calculate the primary reaction with the greatest sensitivity to no,and analyze the sensitivity change and action mechanism under different conditions.Combined with the ROP yield analysis method,the reaction with the largest no consumption was calculated,and its variation with the operating conditions was studied.Based on the analysis of no sensitivity and ROP yield,the path diagram of no generation and consumption is drawn.Combined with the path diagram,the control method of no emission from ammonia combustion flue gas is proposed.Secondly,the flame propagation velocity was measured by image processing combined with area method,and compared with CHEMKIN’s simulation to evaluate the correctness of mechanism analysis.After obtaining the experimental data of velocity,the ammonia combustion temperature was calculated by CHEMKIN and compared with the experimental data to explore the influence of temperature on velocity.The OH radicals influencing the NH₃ combustion chain reaction were calculated by sensitivity and ROP yield analysis,and the NH₃ combustion chain reaction path diagram was drawn.According to the path diagram,this paper puts forward the method to improve the ammonia combustion.Finally,through the experimental results and the discussion of the mechanism,some suggestions for the practical application of ammonia in the future are put forward.