Research On Biomass Plasma Spouted-Fluidized Bed Characteristics

Biomass energy is a form of renewable energy. Plasma pyrolysis is considered as a high efficient means for biomass utilization. While biomass has the properties of low density, bad mobility, low heat value and strong viscosity, it can not easy be fluidized or need large quantity of air in the traditional reactor, as a result it can not completely be pyrolyzed. Spouted-fluidized bed has the advantage of gas-solid solution efficiency and high cycle efficiency, so biomass can achieve good circulation in it. This project associate the advantages of plasma, spouted-fluidized bed and biomass, design and set up a plasma spouted-fluidized bed for biomass pyrolysis. The main hydromechanics of the apparatus at environmental temperature, as well as the flow of particles, the granulation condition, the temperature distribution in the apparatus under the plasma type were tested. By means of add quartz into the apparatus and change the auxiliary gas flow, the temperature distribution at different working condition and the energy distribution in the system were test and analyzed.The research result shows that the main hydromechanics of spouted-fluidized bed at environmental temperature is similar to spouted bed, maximum spouted height decreases as the particle diameter increase, the common pressure drop of the bed and the plenum is higher than separate pressure drop of the bed. This article comes up with a correlate equation of the minimum spouted velocity which suitable to the apparatus as a reference for further research. The temperature test under the plasma condition shows that the mean temperature of the bed is 897K, while the top area has a relative uniform temperature distribution and low temperature gradient in radical direction compare to the bottom area. The addition of quartz can increase the uniformity and the value of the temperature distribution at bottom area. Increase the flow of auxiliary gas the temperature value will drop a little. Energy balance calculation shows that the energy used for reaction account for 38% to total input energy.This project also make calculations of plasma operating temperature, particle circulation rate, heating rate and plasma pyrolysis model. The calculation results show that the plasma jet temperature is about 4000K, particle circulation rate is 0.72kg/s and the particles reach to the plasma jet interface temperature need time 0.025s. Biomass plasma pyrolysis model calculate results show that smaller particle diameter and transport the particle to plasma jet directly can get better pyrolysis effect.