Stochastic Analysis And Optimization Of Key Parameters In Entrained Flow Bed Pulverized Coal Gasification Process

In the coal gasification process,the stochastic fluctuation of gasification input variables will affect the temperature which is one of the core control process parameters,and even the gasification process.The accurate portrayal of temperature distribution and its spatial correlation analysis,and the stochastic optimization of the coal gasification process are of great significance to ensure the safe,efficient and robust coal gasification production process.In this thesis,we take the gasification process of entrained flow bed as the research object,analyze the temperature distribution in the gasifier stochastically,and model and optimize the coal gasification process stochastically.Firstly,the temperature random field model was established based on the Fluent simulation experimental results,and the temperature distribution in different longitudinal profiles in the gasifier was simulated stochastically.The results show that the temperature at the outlet of syngas and ash under different oxygen-coal ratios are non-uniformly distributed,and the highest temperature in different longitudinal profiles decrease,and the temperature distribution in the gasifier shows a trend of increasing first and then decreasing from top to bottom.Then,the correlation coefficients of temperature units at different locations in the redox zone were calculated to study the spatial correlation of temperature distributions.The results show that the spatial correlation coefficients of different regions are all around0.5,and the spatial correlation of temperature distribution near the wall is slightly higher than that in the center of the gasifier.Increasing the oxygen-coal ratio improved the spatial correlation of temperature distribution,however,the difference between the spatial correlation of temperature distribution near the wall and the center of the gasifier was greater.Finally,jump-diffusion stochastic modeling of the noisy variables of the coal gasification process is performed as constraint,and the values of oxygen-coal ratio,steam-coal ratio and pressure parameters are determined by multi-objective stochastic optimization with effective syngas volume fraction and cold gas efficiency as optimization indexes.The results show that the stochastic optimization results in this thesis are more robust compared with deterministic optimization and provide references for decision makers who prefer different gas production indexes.There are 25 pictures,10 tables,and 69 references.