Study On Microwave Pyrolysis Characteristics Of Microalgae And Life Cycle Assessment Of Bio-Oil Power Generation

Growing energy demand and dwindling fossil fuel reserves have stimulated a huge interest in finding alternative renewable energy sources.Currently,microalgae were considered as the suitable feedstocks to produce the next-generation biofuel because of their significant advantages such as fast growth speed,high yield per unit area,high photosynthetic efficiency.Accordingly,it was very imminent to investigate the fast conversion of microalgae biomass into energy.Microwave pyrolysis could make up for high energy consumption of wet biomass?such as microalgae?during drying process,and many researchers have preferred microwave pyrolysis technology of biomass.In this paper,the effects of mixed additives on microwave pyrolysis of microalgae were studied by using microwave pyrolysis technology.The two mixed additives were composed of SiC and Na₂CO₃mixture?SN mixed additive?and SiC and Ca CO₃mixture?SC mixed additive?.Effects of the different weights of addition?SN mixed additives with 5%,10%and 20%;SC mixed additive with 5%,10%,15%and 20%?of mixed additives,different mixing ratios?SiC:Na₂CO₃=0:10,3:7,5:5 and 6:4;SiC:Ca CO₃=5:5,6:4,7:3 and 10:0?and different kinds of additives?single additive and mixed additive?on microwave pyrolysis characteristics of microalgae and unit power consumption of pyrolysis products were studied.Life cycle assessment?LCA?was used to evaluate the resource input and output in the whole process of microalgae biodiesel power generation?including microalgae culture,feedstock transportation,conversion of crude bio-oil,pretreatment,biodiesel production and biodiesel power generation?.Findings were as follows:?1?There was a synergistic effect occurred during the SiC and Na₂CO₃in the SN mixed additive,which could promote pyrolysis.When the weight of addition of SN mixed additive was 10%and SiC:Na₂CO₃=5:5,the SN mixed additive had the best promoting effect on pyrolysis;when the weight of addition of SN mixed additive was 10%and SiC:Na₂CO₃=0:10,mixed additive inhibited the pyrolysis process.?2?When the weight of addition of SC mixed additive was 15%and SiC:Ca CO₃=5:5,the SC mixed additive had the best promoting effect on pyrolysis;and when the weight of addition of SC mixed additive was10%and 20%,the SC mixed additive had obvious inhibitory effect on pyrolysis.?3?The catalytic effect of SN mixed additive with the additive amount of 10%and the mixing ratio of SiC:Na₂CO₃=5:5 on pyrolysis was superior to that with the additive amount of 15%,and the mixing ratio of SC mixed additive with SiC:Ca CO₃=5:5.And the SN mixed additive had lower energy consumption,higher oil and gas production per unit of electricity consumption.?4?The power resource of producing 2000k W·h consumed 98%coal and 2%diesel,and the consumption of coal was much higher than that of diesel.The environmental impacts were Dust?DU?,Acidification?AC?,Global Warming?GW?and Eutrophication?NE?.?5?Microalgae biodiesel power generation had the largest impact on local and the smallest global impact.In other words,microalgae biodiesel power generation could only affect the environment in a certain area and have less negative effect on the environment,so it was a biofuel utilization method worthy of promotion.