Performance Comparison Of Steam And Air-Steam Gasification Reactor
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Date
2022-07-24
Authors
Munisuaran, Kishen
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Renewable energy sources are being used more frequently as a result of rising
energy demand and environmental concerns. A growing source of sustainable energy
is biomass. Thermochemical and biological processes are the most common for turning
biomass to energy. When a gasifying agent is used, the solid fuel is converted into the
gaseous fuel known as PG by a thermochemical process called gasification. High
hydrogen production cannot be attained when air is used as the gasifying agent. To
solve this issue, a gasifying agent will be used because steam can improve hydrogen
production. A self-sustained steam biomass gasifier was modified and fabricated to
enable proper and fully supply of steam to the reactions. Thus, the use of steam alone
and steam incorporated with air as gasification agents was explored in this research.
Steam was generated using an electric steam boiler. The gasifier performance and
gasification processes were characterized based on various parameters such as gasifier
outlet and grate temperature, steam flow rate, steam-to-biomass ratio, heating values
and producer gas composition at the top. The steam flow rates used are in the range of
11.24 to 40 ml/min for steam gasification of wood pellets and optimum steam flow rate
is used for steam gasification of different biomass fuels and air-steam gasification of
wood pellets. As for the gasifier characterization, the highest temperature recorded at
the grate was 545 ºC and 510 ° C at the outlet for steam gasification of wood pellets.
The optimum S/B ratio for producing the desired gas quality and compositions was
found to be 1.9 having the highest HHV of 15.1 MJ/Nm³ in steam gasification of wood
pellets. In steam gasification of different biomass fuels, wood pellets were found to
yield the highest hydrogen and methane concentrations and HHV followed by PKS. As
for air-steam gasification, the highest temperature recorded at the grate was 975 ºC and
905 ° C at the outlet. In this study, the optimum S/B ratio for producing the desired gas
quality and compositions was found to be 1.7 at air flow rate of 50 LPM and optimum
steam flow rate having the highest HHV of 5.27 MJ/Nm³.