Biodiesel Production Using Reactive Distillation: Optimization And Comparative Simulation Study Using Aspen
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Date
2021-06-01
Authors
Chuah, Jing Xuan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Depletion of fossil fuels in the recent years had led to attention of researcher to
develop potential renewable energy as the fossil fuel substitute. Thus, biodiesel is
suggested since it is a good replacement of fossil fuels as a ‘clean energy source’.
However, due to high cost of raw material and operating expenses in conventional
biodiesel production, biodiesel is considered not economically competitive compared
to petroleum-based fuel. This limitation can be overcome by process intensification
(PI) technology. PI technology is applied in intensified biodiesel production by using
reactive distillation column to replace methanol recovery column and reactor.
Reactive distillation (RD) is a process intensification technique that combines
chemical reaction and distillation in a single equipment. To minimize the energy
consumption in RD column, sensitivity and optimization analysis are conducted to
study the effect of operating parameters such as feed temperature and reflux ratio on
reboiler heat duty. Results from sensitivity analysis showed that reboiler heat duty is
directly proportional to feed temperature but inversely proportional to reflux ratio.
Optimized results showed that optimum condition for efficient production of biodiesel
with minimum consumption of energy is at 145oC of feed temperature and reflux ratio
at 1. Besides, the process gains obtained through intensification of a conventional
biodiesel plant by addition of a reactive distillation column is studied. It is found that
intensified process has higher conversion of Jatropha oil into biodiesel compared to
conventional process with reported conversion rate at 48.19% and 32.52% for
intensified and conventional process, respectively. From aspect of energy analysis, hot
utility requirement in intensified process is 60.70% less than that required for
conventional process with reported hot utility requirement at 7.702×104
cal/s and 131.96×105 cal/s for intensified and conventional process, respectively. Besides, reboiler
heat duty in intensified process is 21.84% less than in conventional process with
reported reboiler duty at 69034.1kW and 88327.1kW for intensified and conventional
process, respectively. From aspect of exergy analysis, result showed exergy change
across reactor and methanol recovery column in conventional process are -10.39kW
and -25.54kW, respectively. Whereas exergy change across reactive distillation
column in intensified process is 91.15kW. This implies that exergy is lost or wasted in
conventional process, whereas in intensified process exergy is gained within reactive
distillation column. Thus, this reactive distillation column utilizes fully exergy gained
from other sources.