Effect of Torrefaction on Bio-oil Upgrading over HZSM-5. Part 1: Product Yield, Product Quality, and Catalyst Effectiveness for Benzene, Toluene, Ethylbenzene, and Xylene Production

Hilten, Roger N.; Speir, R.; Kastner, James R.; Mani, Sudhagar; Das, K. C.

doi:10.1021/ef301694x

Cited by 35 publications

(22 citation statements)

References 28 publications

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“…Chen et al also observed S and N content increases in the torrefied sawdust in relation to raw feedstock. Hilten et al also stated important increases in N contents in torrefied pine chips.…”

Section: Resultsmentioning

confidence: 94%

Effect of Rice Husk Torrefaction on Syngas Production and Quality

et al. 2017

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The aim of this study was the production of a good quality gasification gas (syngas) with rice husk residues. This material was torrefied before gasification with the aim of improving this last process, and the effect of torrefaction time and temperature was investigated. The variation of temperature from 200 to 300 °C decreased moisture and volatile matter and, consequently, increased higher heating value (HHV). The increase of reaction time from 30 to 60 min at 250 or 300 °C had a milder effect than the rise of torrefaction temperature. The optimum conditions for the rice husk torrefaction prior to gasification were 250 °C and 30 min, as the torrefied material presented an HHV of 22.1 MJ/kg daf and an ash content of 17.7%. The torrefaction increased the rice husk in extractives 14.8% (vs 12.6% in the raw material), mainly in nonpolar extractives and lignin (36.4% vs 28.9%). Py-GC/MS analyses determined that raw rice husk presented a monomeric composition of lignin (H/G/S) of 4:12:1 and ratio of carbohydratesto lignin of 3.3 while the torrefied material showed, respectively, 3:9:2 and 3.9. Compared with the raw rice husks, the gasification of torrefied rice husk at 250 °C presented a syngas poorer in CO2 (39% vs 24%) and richer in H2 (31% vs 36%) and CO (17% vs 24%) and produced less tar (7.6 g/m3 vs 3.5 g/m3) but released more pollutants (186 vs 92 ppmv of H2S and 1284 vs 734 ppmv of NH3).

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Section: Resultsmentioning

confidence: 94%

Effect of Rice Husk Torrefaction on Syngas Production and Quality

et al. 2017

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“…One of the greatest disadvantages of bio-oil is its high oxygen content. This high oxygen content requires an energy and hydrogen-rich catalytic upgrading process . Many of the oxygen-rich products are generated from the hemicellulose and cellulose fractions.…”

Section: Introductionmentioning

confidence: 99%

“…The lignin fraction does contribute to the oxygen content, but because of the nature of the phenolic ring, the lignin fraction contributes more significantly to the carbon content of the bio-oil. Phenolic structures are easier to upgrade than carbohydrate-derived bio-oil compounds using catalytic hydrotreatment, have higher carbon-to-oxygen ratios, and can therefore produce a more energy-dense biofuel product …”

Section: Introductionmentioning

confidence: 99%

Effects of Lignin Content and Temperature on the Properties of Hybrid Poplar Bio-Oil, Char, and Gas Obtained by Fast Pyrolysis

2017

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Eight genetically different hybrid poplar samples with varying lignin content were pyrolyzed at 500 °C using a micropyrolysis unit, which was directly connected to a GC/MS. Four of these hybrid poplar samples with a range of lignin content were then pyrolyzed at temperatures of 550 and 600 °C to determine the effects of pyrolysis temperature on product distribution among bio-oil, char, and gas. At a pyrolysis temperature of 500 °C, an increase in poplar lignin content from 17% to 22% decreased the relative bio-oil yield from 73% to 65%, increased the char yield from 17.5% to 27.2%, and decreased the yield of lignin-derived phenolic species in the bio-oil by 3%. At the higher pyrolysis temperature of 600 °C, there was neither a decrease in the yield of bio-oil nor an increase in the char yield, and there was an increase in the relative abundamnce of bio-oil phenolics compared to the results obtained at 500 °C. According to these results, higher temperatures are needed to increase the yield of bio-oil and the content of phenolic species in bio-oil.

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“…The mass yield from torrefaction usually is less than 1. Therefore, even though there is some biomass energy loss during torrefaction due to the loss of volatile organic material (e.g., between 3-17% as reported by Hilten et al, 2013a), the energy yield usually is greater than one because of the reduced torrefied product mass. Hilten et al (2013b) also reported that the net thermal process efficiency is defined as the energy yield in the torrefied products divided by the total energy input (e.g., the energy content of the feedstock plus energy added to the heat and run the torrefaction process).…”

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confidence: 99%

Biomass Torrefaction Process, Product Properties, Reactor Types, and Moving Bed Reactor Design Concepts

et al. 2021

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Torrefaction, a thermal pretreatment process, is gaining attention as it improves the physical properties and chemical composition of biomass for recycling. During torrefaction, biomass is heated slowly in an inert or oxygen-deficit environment to a maximum temperature of 300°C. The torrefaction process creates a solid uniform product with lower moisture and higher energy content than the raw biomass. During torrefaction, moisture and some volatile organic compounds volatilize from the biomass. Depending on stoichiometry and other conditions, non-condensable gas species, including CO and CO2, are formed. The specific objectives of this research are to: 1) understand the impact of torrefaction on product quality in terms of the physical properties, chemical composition, and storage behavior of the biomass; 2) discuss the various reactors used for biomass torrefaction; and 3) develop a model for designing a moving bed torrefier, considering fundamental heat and mass transfer calculations. Torrefaction improves the physical properties, chemical composition, and energy and storage properties of biomass. Torrefaction of biomass at 300°C increases the energy content by about 30% as compared to the raw biomass. For example, when torrefied, the calorific value of the biomass increases from about 18–19 MJ/kg to about 20–24 MJ/kg. The torrefied material has a moisture content of about 1–3% wet basis (w.b.). The loss of the hydroxyl group during torrefaction makes the biomass hydrophobic. The brittle nature of the torrefied biomass makes it easier to grind. The devolatilization and carbonization reactions change the proximate and ultimate composition. The carbon content increases, whereas the hydrogen, oxygen, and nitrogen content of the biomass decreases. Despite its superior properties, the commercialization of torrefaction technology is slow due to challenges associated with reactor design and final product quality. The different types of reactors that are typically used for biomass torrefaction are the fixed bed, rotary drum, microwave, fluidized bed, and horizontal and vertical moving bed. The moving bed reactor has gained popularity among the different torrefaction reactor designs as it is easy to operate and scale. In addition, it helps produce a uniform torrefied product. In this paper, different moving bed torrefaction and gas recycle concepts are conceptualized to assess the features, advantages, and disadvantages of various design and operating concepts. These designs include example concepts for: 1) vertical and horizontal torrefaction reactors; 2) recycle of all or a portion of the torrefier off-gas; 3) counter and co-flowing gas and biomass in the torrefier; 4) controls for the system temperatures, pressures, flow rates, and gas compositions; and 5) the ability to sample the biomass feed, torrefied product, and gas streams for analysis as needed to investigate the thermal decomposition, physical behavior, and operational performance of the torrefaction system. The article also briefly describes the solid feed system, gas supply and recycle system, solid product management, torrefier gas monitoring, control system, and fugitive dust emissions control. The model presented in this paper includes a set of equations for basic calculations to configure the torrefaction reactor dimensions, such as diameter and height of the moving bed torrefier for different capacities based on target and calculated solids and gas velocities, residence times, and temperatures.

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Effect of Torrefaction on Bio-oil Upgrading over HZSM-5. Part 1: Product Yield, Product Quality, and Catalyst Effectiveness for Benzene, Toluene, Ethylbenzene, and Xylene Production

Cited by 35 publications

References 28 publications

Effect of Rice Husk Torrefaction on Syngas Production and Quality

Effect of Rice Husk Torrefaction on Syngas Production and Quality

Effects of Lignin Content and Temperature on the Properties of Hybrid Poplar Bio-Oil, Char, and Gas Obtained by Fast Pyrolysis

Biomass Torrefaction Process, Product Properties, Reactor Types, and Moving Bed Reactor Design Concepts

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