Biomass Pyrolysis Technology by Catalytic Fast Pyrolysis, Catalytic Co-Pyrolysis and Microwave-Assisted Pyrolysis: A Review

Abstract

<jats:p>With the aggravation of the energy crisis and environmental problems, biomass resource, as a renewable carbon resource, has received great attention. Catalytic fast pyrolysis (CFP) is a promising technology, which can convert solid biomass into high value liquid fuel, bio-char and syngas. Catalyst plays a vital role in the rapid pyrolysis, which can increase the yield and selectivity of aromatics and other products in bio-oil. In this paper, the traditional zeolite catalysts and metal modified zeolite catalysts used in CFP are summarized. The influence of the catalysts on the yield and selectivity of the product obtained from pyrolysis was discussed. The deactivation and regeneration of the catalyst were discussed. Catalytic co-pyrolysis (CCP) and microwave-assisted pyrolysis (MAP) are new technologies developed in traditional pyrolysis technology. CCP improves the problem of hydrogen deficiency in the biomass pyrolysis process and raises the yield and character of pyrolysis products, through the co-feeding of biomass and hydrogen-rich substances. The pyrolysis reactions of biomass and polymers (plastics and waste tires) in CCP were reviewed to obtain the influence of co-pyrolysis on composition and selectivity of pyrolysis products. The catalytic mechanism of the catalyst in CCP and the reaction path of the product are described, which is very important to improve the understanding of co-pyrolysis technology. In addition, the effects of biomass pretreatment, microwave adsorbent, catalyst and other reaction conditions on the pyrolysis products of MAP were reviewed, and the application of MAP in the preparation of high value-added biofuels, activated carbon and syngas was introduced.</jats:p>

Catalytic Fast Pyrolysis of Lignocellulosic Biomass to Benzene, Toluene, and Xylenes

“…The pyrolysis vapor must condense quickly to avoid unwanted secondary reactions such as cracking. Alkali and alkaline earth metal ions in biomass feed pose substantial challenges to the process (addressed in Pretreatment) [17,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

“…This method was successful to create intraparticle mesoporous materials which then improved diffusion. By coupling ZrO 2 with desilicated zeolites, a more active zeolite was accompanied with longer catalyst lifetimes [19]. The resulting coke was "softer" (i.e.…”

“…As a feed, lignocellulose is highly deficient in hydrogen. It might be plausible to increase this ratio by co-feeding a material rich in hydrogen [19,27]. By increasing this ratio, not only is coke reduced, but higher yields of aromatics and olefins result.…”

Biorefinery via Catalytic Upgraded Fast Pyrolysis of Biomass

“…Although CFP of biomass can promote the generation of aromatics and the removal of oxygen in pyrolysis products, it leads to hydrogen deficiency and limits the content of hydrocarbons. In order to make up for this defect, an hydrogen-rich material is added to the biomass to realize "Catalytic fast co-pyrolysis" (CFCP) and this solution is considered an effective way to alleviate the hydrogen shortage and reduce the amount of coke [28][29][30][31][32][33][34][35][36].…”

Comprehensive Kinetic Study of Pyrolysis of Sunan Candlenut: The Effect of Using Iron Oxide, Zeolite and ZSM-5 as Bed Materials

“…The conversion of lignocellulosic biomass through pyrolysis technology still has many challenges, as bio-oil has a high viscosity, high oxygen content, and temperature instability. Therefore, a catalyst is required to improve the quality of pyrolysis vapor [12]. The yield and selectivity of catalytic pyrolysis depends on the type of catalyst, ratio of biomass amount to the catalyst, pyrolysis temperature, and residence time [13].…”