The Influence Of Operation Parameter And Scale-up On Coal Gasification Process Of Integrated Gasifier

THE INFLUENCE OF OPERATION PARAMETER ANDIntegrated gasifier based on ash agglomerating fluidized bed designed by Institute of Coal Chemistry, Chinese Academy of Sciences, is a new gasification technology, which integrate advantage of small investment, low-energy-waste, lithotype wide adaptability of fluidized bed and advantage of high reaction temperature, high carbon conversion of entrained bed. The integrated gasifier, however, is facing the challenge of efficiency, stability and engineering scaling up, owing to intricate structure, hydrodynamics in fluidized system, heat transfer, mass transfer and coal gasification reaction. In order to study substantial of influence of operation parameter on coal gasification process and perfect coal gasification theory considering heat and mass transfer and volume effect, the following research contents are listed:A equivalent reactor network of integrated gasifier is established with CHEMKIN based on mass balance, energy balance and chemical kinetics, which divide the reactor into five zone through hydrodynamics characteristics of integrated gasifier. Influence of coal feed, oxygen feed, steam feed of fluidized bed and entrained bed on thermo chemistry properties is simulated by established model. In addition, in order to simplify the scale effect of integrated gasifier, entrained bed is neglect, and only study the scale effect of ash agglomerating fluidized bed. The following conclusion has been discovered:1. The equivalent reactor network model of integrated gasifier can reflect essential problems of coal gasification process influenced by operation parameter, especially reaction mechanism of the carbon contained fly ash, because the model considered hydrodynamics, mass and heat transfer between various areas, different activity of carbon contained between raw coal and fly ash.2. The amount of coal feed, oxygen feed and steam feed of fluidized bed influence carbon conversion, reaction temperature and gas composition of fluidized bed directly, and the change of carbon conversion of fluidized bed make carbon contained fly ash changeable, which lead to low reactivity entering into entrained bed carbon change and then influence thermo chemistry characteristics of entrained bed. In order to prevent temperature increase and carbon conversion decrease sharply, operation parameter of entrained bed should be adjust when adjust operation parameter of fluidized bed, due to the coal feed and oxygen feed of fluidized bed influence temperature and carbon conversion greatly. Steam feed, however, have an less influence on temperature and carbon conversion.3. The amount of coal feed, oxygen feed and steam feed of entrained bed influence carbon conversion, reaction temperature and gas composition of entrained bed directly. The change of product temperature of entrained bed make temperature of fluidized bed change, and then influence coal gasification characteristics of fluidized bed. Main attention should be paid on the influence of operation parameter of entrained bed on thermo chemistry characteristics of entrained bed, due to the influence of operation parameter of entrained bed on fluidized bed is tolerable. 4. Gas phase backflow rate from annular dense-phase zone to jetting zone and volume of jetting zone changed nonlinearly in the scale-up process; Gas phase backflow rate decreased relatively after scale-up makes the temperature of jetting zone decrease and jetting zone volume expand relatively. Clearly, the residence time of coal particles would prolong. However, the influence of volume on the temperature of jetting zone is more than that of an increase in Gas phase backflow rate. All resulted in the temperature of jetting zone increasing from 1529K to 1662K;The temperature of annular dense-phase zone decreases, however, residence time of coal particles in annular-phase zone prolong which make carbon conversion increase;The scale-up of influence on gas composition can be neglect.