Coal Classified Conversion Of Pressurized Double Fluidized Bed:Coal Pyrolysis Characteristics And Pilot Reactor Design

The classified conversion technology of pressurized coal is an effective method for high efficiency and clean utilization of coal.In order to promote the development of coal classification conversion technology at the core of coal pyrolysis and semi-coke combustion,combined with the engineering demand of the classification conversion of pressurized dual fluidized bed coal,the dynamic characteristics of coal pressurized pyrolysis and the law of low temperature pyrolysis under pressure are studied in this paper.On this basis,the structural design and optimization of a pilot-scale pyrolysis reactor for pressure-sparing fluidized-bed coal fractionation conversion are carried out,then proposing a program for the operation of a pressurized spout fluid-bed coal pyrolysis pilot reactor,and completing the pilot plant construction,debugging and verification.The kinetic characteristics of coal pressurized pyrolysis and the law of pressurized pyrolysis at low temperature are studied.Taking the coal of Shanxi Hei Long Gou as the research object,the emission characteristics of the volatile matter are analyzed by the thermogravimetric mass spectrometry(GC-MS)curve,and the kinetic characteristics of the coal pressurized pyrolysis reaction are investigated by the pressure thermogravimetric experiment.A coal pressure pyrolysis experimental system is established to study the effects of different temperatures(500?~700?),pressure(0.1MPa~0.5MPa),atmosphere(nitrogen and gas),particle diameter(0~3mm and 0~6mm)on the yield of coal pyrolysis products(semi-coke,tar and gas),and to detect and analyze the pore structure of semi-coke,gas characteristics and tar quality under different pyrolysis conditions.The results show that the pyrolysis volatiles are mainly released at the temperature of 400?~700?,while the pressure suppressing volatilization of the analyzed,it will increase gas calorific value,promote the lightening of pyrolysis tar and the development of semi-coke pore structure.On the basis of the experiment,the structural design and thermal calculation of the 50 kg/h pyrolysis reactor at the pilot scale are carried out,and a three-dimensional mathematical model is established for the coupling of gas-solid flow and chemical reactions in the coal pyrolysis process in a pressurized spouted fluidized bed.Then the structural parameters and operating data of the pilot pyrolysis reactor are verified and optimized by numerical simulation calculations.And the optimized structure of the pilot pyrolysis reactor with a spouted fluidized bed treatment capacity of 50 kg/h was proposed.Afterward studying the effects of different pressures(0.1MPa,0.3MPa,0.5MPa)on the coal pyrolysis process in a spouted fluidized bed pilot pyrolysis reactor.On the basis of the numerical simulation calculation of a pilot scale 50kg/h pyrolysis reactor,a pyrolysis reactor with a height of 1.5m and an internal diameter of 0.2m is determined,and the operation of the pressurized pyrolysis fluidized bed pilot pyrolysis reactor is proposed.Meanwhile planning to conduct pilot plant construction,commissioning and verification.The results show that the pressure will decrease the yield of pyrolysis tar and increase the gas yield and calorific value under nitrogen atmosphere,which are consistent with the numerical simulation results.The operation verification and preliminary test of the pyrolysis part of the pilot plant coal are completed,which can provide theoretical basis and data support for the scale-up design of industrial devices.