煤在加压流化床富氧燃烧条件下的碳转化规律

Carbon conversion rules of oxy-fuel coal combustion in pressurized fluidized bed

在15 kW加压流化床富氧燃烧实验台上,进行了内蒙古烟煤在850～900℃下的加压富氧燃烧实验,研究了压力为0. 1～0. 4 MPa、空气和21%～30%氧浓度的O_2/CO_2气氛下燃烧的碳转化规律.研究结果表明:稳态富氧燃烧条件下,加压流化床富氧燃烧实验台干烟气中CO_2浓度均超过90%.提高燃烧压力有利于提高碳转化率和CO_2生成率,有利于降低CO生成率.在压力0. 1～0. 3 M Pa范围内,CO_2生成率随着压力的增加基本呈线性递增关系,从85%左右增加到93%左右.进一步增加压力,CO_2生成率逐渐趋于平稳,并保持在较高水平.在压力为0. 4 MPa条件下,CO_2生成率增加到95%左右.提高O_2/CO_2气氛的氧浓度能够提高碳转化率和CO_2生成率,但是随着压力的提高,氧浓度对碳转化率和CO_2生成率的影响减小.

A combustion experiment of the Inner Mongolia bituminous coal was conducted at furnace temperature from 850 to 900 ℃ in a 15 kW pressurized oxy-fuel fluidized bed. The carbon conversion rules were investigated in the pressure range from 0.1 to 0.4 MPa, and in the atmosphere between air and O2 /CO2 mixtures. The results show that the CO2 concentration at the outlet of the pressurized fluidized bed is over 90% under the steady condition of oxy-fuel combustion. Increasing combustion pressure can increase the carbon conversion rate and reduce the CO2 generation rate. The CO2 generation rate is linearly increased from about 85% to 93% with an increase in pressure from 0.1 to 0.3 MPa, while the CO2 generation rate reaches 95% at 0.4 MPa. The CO2 generation rate gradually levels off and stays at a high level as the pressure further increases. The carbon conversion rate and the CO2 generation rate increase with the increase of O2 concentration. However, the impact of O2 concentration is weakened with the increase of the combustion pressure.