Design And Experiment On Down Flow Tube Reactor For Biomass Pyrolysis Liquefaction

Fast pyrolysis of biomass is a technology that made the biomass to be bio-oil through the thermo-chemical reaction. It is an efficient way of using biomass. A down flow tube reactor (DFTR) of biomass pyrolysis was designed, which was based on the technology of biomass powder heated by ceramic balls that were used as the heat carriers in the reactor for bio-oil production. The system consists of heat carriers exchanging device, feeding device, V-down flow tube reactor, separation device, condensing device, heat carrier circulation conveying equipment and electric control part.In order to design the new down flow tube reactor of biomass pyrolysis properly, we studied the pyrolysis gas spray condensing system, and some key parameters of sprinkler system were confirmed. Then, a bio-oil circulation spray condensing system was developed based on it. In order to study the regular of biomass pyrolysis, Taking corn stalk as feedstock, with V-down flow tube reactor, this research made fast pyrolysis liquefaction experiments at the heat carrier temperature of475℃,525℃and575℃. The mass ratio of solid heat carriers and biomass was20:1. We also analyzed the characteristics of pyrolysis productions, including bio-oil, carbon powder and incondensable gas. According to the experimental results, we drew some conclusions as followings.1. The results of spraying cold test showed that the spiral nozzles used in the test were suitable for spray tower in fast pyrolysis and met the need of spray medium. It was the most appropriate to the V-down flow tube reactor that fluid pressure was0.2MPa and orifice diameter was5.6mm.2. In the pyrolysis experiment of ceramic balls as heat carriers, with the rising of temperature of ceramic balls the yield of bio-oil increased first and then decreased. The bio-oil collection rate of corn straw pyrolysis was effected significantly by temperature. When the temperature of heat carriers were525℃bio-oil collection rate was the highest, reaching53.32%.3. The experiment showed that the biomass pyrolysis liquefaction system of new type down flow tube reactor with solid carriers heating was working stably and had a high reliability and bio-oil collecting rate. During the experiment, we found many problems and improved, and provided a reference for the designs of pyrolysis reactor in the future.