The Modification Of Wire-mesh Reactor Based On The Reduction Of Secondary Reactions During Cellulose Pyrolysis

Biomass energy is abundant and renewable.And cellulose is an important component of biomass.The study of pyrolysis mechanism is helpful to improve the quality of bio-oil.In the study cellulose pyrolysis,the nascent products always need to be characterised.However,it was difficult for the traditional pyrolysis equipments to avoid secondary reactions and obtain the nascent products in pyrolysis process.Wire-mesh reactor has been recognized to be the minimized secondary reaction reactor.Through several decades of development and modified,the performance of minimizing secondary reaction has been improved again and again.Firstly,the fluid model of tar collection trap in wire-mesh reactor was contributed in ANSYS CFX,and transient simulation was carried out on three commonly used heating rates(1K/s,10K/s,and 100K/s).The simulation results showed that there were backflows in the two commonly used tar collection traps to varying degrees,and the intensity of the backflow increased with the experimental temperature increasing.A secondary reaction of the gaseous products and the sample particles would be caused by the backflow around the inlet,and the secondary reactions in the gaseous products would be intensified.The backflow was caused by temperature difference.The density of gas is sensitive to temperature.The density of the gas increase as the temperature goes high;and vice versa.The structure of tar collection trap was modified by the cause of backflow.An adiabatic cavity was added between the cooling chamber and the collecting port to reduce the temperature gradient in the tar collection trap.Similar to the two commonly used tar collection traps,the flow field in the new tar collection traps on three commonly used heating rates was simulated.Comparing the simulated calculation results of the old and new tar collection traps,it was found that the modified tar collection trap had a relatively uniform internal temperature distribution,a smaller proportion of backflow and a shorter time for carrier gas to arrival the condensing area.Therefore,the modified tar collection trap will performance better in reducing secondary reactions during cellulose pyrolysis in wire-mesh reactor.