Process Model-Based Validation of the Intensification of Biomass Fast Pyrolysis in a Fluidized Bed via Autothermal Operation

Abstract

A model for the fluidized-bed pyrolysis of biomass is extended to enable the simulation of intensified autothermal operation. In this system, partial oxidation of char and pyrolysate species replaces an external heat source to supply the enthalpy of pyrolysis, greatly increasing the throughput of a given fast pyrolysis reactor. Oxidation reactions are compiled from CRECK and other literature sources and extended to cover the species found in pyrolysis products, including a derivation of the catalytic effect of ash on char combustion from experimental studies at Iowa State University (ISU). Results indicate a roughly 3-fold increase in biomass throughput for a given reactor volume at the pilot scale with minimal loss of valuable products, in agreement with published data from the 3 × 10 −2 m 3 reactor operated by ISU. A proposal for a 250 ton/day commercial-scale biomass pyrolysis reactor is analyzed, showing that the same size reactor operated by heating the fluidizing gas externally would have only one-tenth the capacity; if operated by heating the sand externally, the sand would need to circulate at an impractical 0.7 bed volume per minute rate to maintain a 250 ton/day biomass throughput.

Carbon‐negative syngas production: A comprehensive assessment of biomass pyrolysis coupling chemical looping reforming

“…consumption and production is essential for autothermal operation, otherwise, the reactor temperature will gradually deviate from the set value. 50 Designing a suitable heat supply scheme is a crucial step in ensuring the autothermal operation of biomass gasification, which is a heat absorption process. The following energy supply schemes were used for the four different processes mentioned earlier:…”

“…The aim is to maintain stable system operation without external energy or fuel. A balance between energy consumption and production is essential for autothermal operation, otherwise, the reactor temperature will gradually deviate from the set value 50 . Designing a suitable heat supply scheme is a crucial step in ensuring the autothermal operation of biomass gasification, which is a heat absorption process.…”