Sulfur Transfer Characteristics and Pyrolysis Simulation in the Coal Polygeneration Process

摘要

In the polygeneration process of coal pyrolysis/circulating fluidized bed (CFB) combustion, the sulfur transformation characteristics and a heat transfer, reaction, pyrolysis mathematical model for the non-isothermal coal particles has been studied. The results show that, the circulating ash was effective in capturing the gaseous sulfur. The sulfur fixed in ash was increased by the increase in pyrolysis temperature and the decreased in ash particle size. CaO and Fe_2O_3 in circulating ash displayed significant effect of sulfur retention. The pyrolysis model calculated that, the maximum temperature difference between the core and surface of coal (5 mm) has reached 440 K at the bed height of 0.02 m. The layer closer to the coal core has a higher but later peak value of the devolatilization rate. The temperature of pyrolysis gas and circulating ash is always close.