Gasification kinetic parameters of coal char based on the random pore (RPM) model are obtained with CO2 and H2O using a high-pressure thermogravimetry analysis (TGA) under atmospheric pressure and 4.0 MPa pressure, considering the influence of internal diffusion and particle structure varying with carbon conversion. The Chemical Percolation Devolatilization (CPD) model is used to modify the actual volatile content. Through the coupling of the gasification kinetic reaction model, a comprehensive numerical simulation method of the entrained flow gasification process is established. This method is used to simulate the typical gasifier of HTL (a gasification technology of Changzheng Engineering Co.) in an industrial plant. The research shows that the intrinsic reaction parameters obtained by TGA under high pressure can give a more reasonable reaction state of coal char particles in the gasifier than that measured under atmospheric pressure, and the simulation results are in good agreement with the industrial data. In addition, HTL adopts a single top-fired burner and multi-channel swirling feed type. The particles are entrained and mixed with swirling oxygen, and the combustion reaction is completed quickly in the upper part of the gasifier. In contrast, the gasification reactions are relatively slow and mostly dominate in the recirculation zone and pipe flow zone, leading to high carbon conversion.
Safety Management Performance of Air Traffic Control is affected by many factors. Via questionnaire statistics analysis and Exploratory Factor Analysis (EFA) to optimize items and extract factors, the authors confirm five main effective factors at last, including work initiative, communication and exchange, team cohesion, system completeness and leadership management, and all of them have passed the reliability test and validity test so as to enhance the level of safety management of Air Traffic Control.
The research object in this paper is an industrial HTL gasifier in a plant. A three-dimensional model is built. The chemical percolation devolatilization (CPD) model is used to calculate the pyrolysis reaction. Considering the gas diffusion in the inner pores of the particle and the evolution of pore structure, the random pore model (RPM) was used to simulate the chemical reaction on the particle surface, and the gasification reaction kinetic parameter of char was measured by high-pressure thermogravimetry analysis. The slag model was constructed to describe the formation process and distribution of slag. Through the coupling of the above models, a simulation method that combines several submodels for the entrained flow gasifier is built, and the results from simulation are in good agreement with the industrial data. Furthermore, the effect of the uniformity of pulverized coal injection was analyzed by this method. The simulation results reflect that the asymmetric feed of coal will affect gas-solid mixing and reduce carbon conversion, and it leads to a higher local wall temperature and a lower ratio of crude slag to fine slag.
Aiming at the dry pulverized biochar fuel refined by thermochemical conversion technology, its properties were obtained through experiment. By blending 5% additives to improve the ash fusion characteristics of biomass particles and considering the viscosity-temperature characteristics and the matching principle of CO2 reaction activity, the entrained flow gasification technology scheme of biomass particles was formulated. Based on the gasification reaction kinetics of dry pulverized biochar, a numerical simulation model was established to predict the flow characteristics, syngas composition, and particle conversion process in the gasifier. The results show that under the swirling entrainment and centrifugal force, the oxidizing reaction of particles is completed in the upper part of the gasifier quickly after mixing with oxygen. And the gasification reduction reaction occurs in the recirculating area and the pipe flow area. These effectively complete the conversion of char. The simulation results are in good agreement with the equilibrium calculation values, which proves the feasibility and rationality of the biomass particle entrained flow gasification technology scheme based on the HT-L.
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