(574d) Kinetics and Characteristics of Steam Hydrogasification of Biomass by Using An Inverted Stirred Batch Reactor

Our research group is developing a multi-step thermal chemical process to convert carbonaceous matter into liquid fuels and chemicals. It is based on steam hydrogasification and is referred to in this study as the CE-CERT process. This process appears to offer several advantages in carbon efficiency and cost compared to other mainstream gasification technologies. The initial reactor in this process is the Steam Hydro-gasification Reactor for Steam Hydro-gasification Reaction (SHR) to produce the synthetic output gas. This study will describe the design, construction details and application of a new novel laboratory-scale batch reactor that allows for further fundamental laboratory studies of the kinetics and characteristics in the SHR process to complement other on-going pilot scale development of the CE-CERT process.

The newly designed batch reactor is an inverted stirred system with a pressure-driven feedstock loader that can rapidly load the feedstock material into the reactor at defined temperatures. This is compared to our previous batch reactor system that required long delays when the reactor is heated with the feedstock slowly reaching the desired reaction conditions. This unique design results in rapid heating of the feedstock to the target temperature and more closely represents the thermal environment of our continuously fed fluidized bed reactor being developed for the pilot and commercialized size systems. This allows for kinetic and product studies at a fraction of the time and cost. Additionally, the new batch reactor is built with a non-reactive, non-catalytic quartz vessel inserted into the metal reactor vessel to hopefully minimize any potential metal wall effects on the kinetics. Initial studies using the newly designed reactor shows an increase in several reaction kinetic rates; we believe the consequence of the stable reaction temperatures and the rapid heating rate.

This study will also present the results of the steam hydrogasification of biomass (pinewood) at temperatures ranging from 933K to 973K, under a H2 environment and a H2O to carbon mass ratio 2.5:1 using the inverted stirred batch reactor. The results indicate that the influence of the rapid heating rate not only increased the overall carbon conversion within the batch SHR system but also significantly affected the kinetic rates of all of the SHR reactions. In particular, an increase in the reaction temperature promoted carbon conversion of the biomass and enhanced the formation rate of CH4 and CO in the SHR process.