An Overview of Techno-economic Analysis and Life-Cycle Assessment of Thermochemical Conversion of Lignocellulosic Biomass

Techno-economic and life cycle assessment on lignocellulosic biomass thermochemical conversion technologies: A review

This book chapter presents a comprehensive overview of the techno-economic analysis of various thermochemical biomass conversion technologies for the production of fuels, chemicals and electricity. In the first part of the chapter, a brief introduction on the importance of alternative energy sources and the need for the techno-economic analysis for thermochemical conversion processes are discussed. In the next part, various thermochemical routes for biomass conversion processes are described. The reactor configurations, operating parameters and product composition for each of these processes are also discussed. The third section of the chapter focuses on the techno-economic analysis methodology and different steps involved in carrying out the feasibility of biomass conversion processes. Different process modelling tools and cost estimation methods are also discussed in this section. While in the fourth section, different techno-economic studies carried out by various researchers for the production of fuels, chemicals and electricity through thermochemical conversion routes are discussed in terms of process description, and the results are reported. In the final section, two case studies are discussed in details for techno-economic analysis. One case study is of fast pyrolysis for transportation fuel production, and the second one is for dimethyl ether (DME) production through gasification of biomass. This chapter will be helpful for understanding different techno-economic studies available and comparison of different thermochemical conversion routes to get the desired end product at the minimum cost.

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Thermochemical conversion of lignocellulosic biomass and downstream processing represents an attractive alternative in biomass-to-liquid fuels (BtL) production. There are several thermochemical conversion routes that not only can produce fossil-like fuels but also can simultaneously produce a wider range of fuels in terms of gasoline and diesel profiles. In this work, synthesis, evaluation, and integration of conversion of softwood biomass to liquid transportation fuels are investigated within a systematic framework. Five BtL conversion processes were presented by combining promising thermochemical conversion, upgrading, and separation technologies. Process flowsheet setups and simulations are performed with Aspen Plus version 8.8. The total production processes are evaluated with both products profiles and costs indicators for capital, energy, and total annual costs. Finally, opportunities for process integration to improve the process performance are explored for four integration scenarios. The base cas...

Motivated by the population growth, climate change and limited fossil fuel resources, renewable alternatives for fuels and chemicals production are becoming more and more important. Biomass, especially residual lignocellulosic biomass shows a significant potential as feedstock for bioenergy, due to its high carbon content and short-term availability. Among the thermochemical conversion technologies, fast pyrolysis for biomass liquefaction can be considered already well stablished, as several commercial plants are spread worldwide. However, fast pyrolysis bio-oil, the main product of fast pyrolysis, currently shows limited bioenergy application as boiler fuel for heat production. It can be explained by its chemical composition and properties, as fast pyrolysis bio-oil is an acidic multi-component product, with low energetic density due to its high content of water and oxygenated compounds. Moreover, wood is the only feedstock currently used commercially. In order to expand the feedstock range and application viability, an additional upgrading treatment may be required in order to improve the fast pyrolysis properties, meeting existing fuel standards. In order to do so, catalytic hydrotreatment is considered a promising upgrading treatment, as it is a well-known technology currently applied in petroleum refineries for heteroatoms removal from crude oil. However, due to the differences in chemical composition, the hydrotreatment conditions applied to crude oil cannot be simply applied to fast pyrolysis bio oil. Although research in this field has been carried out for a few decades, there are still open questions to enable hydrotreatment to produce fuel oils from residual biomass in stable processes. By developing a robust fast pyrolysis bio-oil hydrotreatment process, small biorefineries units could be installed near to feedstock sourcing or even be installed in biorefinery units already stablished, such as a sugarcane biorefinery, in which high volumes of residual biomass are generated. Also, co-processing of crude oil and fast pyrolysis bio-oil in petroleum refineries may be a feasible option. In view of the importance of the hydrotreatment for expansion of the range of chemicals obtained by thermochemical conversion of residual biomass, the presented work investigated the hydrotreatment of fast pyrolysis bio-oil applying nickel-based catalysts. In a systematic evaluation nickel-based catalysts with different metal loading, supports and promoters have been studied. Overall, six nickel-based catalyst were screened and compared to ruthenium supported in activated carbon. The hydrotreatment conditions in terms of reaction time, temperature and pressure were optimized and fast pyrolysis bio-oils derived from beech wood and residual biomass (sugarcane bagasse) were hydrotreated. Additionally, the heavy phase separated from beech wood bio-oil, characterized by its high content of lignin-derived compounds, was hydrotreated. The effect of deactivation by sulphur on the hydrotreatment was investigated by use of model substances in a continuously operated trickle bed reactor, since with this reactor the deactivation can be observed depending on time (in contrast to batch experiments). Finally, a 2 step upgrading approach of a previously upgraded fast pyrolysis bio-oil was proposed and verified. Initially two high loaded nickel-based catalysts (monometallic nickel and nickel chromium) were evaluated in comparison to Ru/C by batch hydrotreatment of beech wood bio-oil at 80 bar, 4 h, 175 °C and 225 °C. Both nickel-based catalysts revealed similar hydrodeoxygenation activities for the conditions applied and the nickel catalysts showed the higher hydrogenation activity compared to Ru/C. The nickel-chromium catalyst demonstrated the highest activity for conversion of organic acids, ketones and sugars, attributed to the strength of the acid sites promoted by chromium oxide. When applied in a second hydrotreatment step of a previously upgraded oil, the oxygen content of the oil was reduced by 64.8 % in comparison to the original feedstock while the water concentration was reduced by 90 %. Nearly 96 % of the organic acids were converted and the higher heating value was increased by 90.1 %. Despite nickel-chromium demonstrated the best activity in the one step hydrotreatment reactions and contributed significantly in the 2-step upgrading, the oxygen content of 25.3 wt.% dry basis in the upgraded oil was still considered high. Thus, the upgrading conditions were further optimized, aiming to achieve higher hydrodeoxygenation performance. The conditions of batch hydrotreatment were optimized with nickel-chromium catalyst considering two pressures (80 and 100 bar), four temperatures (175 °C, 225 °C, 275 °C and 325 °C), for both the complete beech wood fast pyrolysis bio-oil, as well as for the heavy phase after spontaneous separation induced by intentional ageing of the bio-oil. At higher temperatures, increased hydrodeoxygenation levels were reached, while at higher pressure larger hydrogen consumption was observed with no significant influence on hydrodeoxygenation. The best conditions among all tested was obtained by hydrotreating the beech wood bio-oil at 325 °C and 80 bar; in this case, 43 % of hydrodeoxygenation was reached. Although improved hydrodeoxygenation activity observed with nickel-chromium at optimized conditions, the results motivated the synthesis and evaluation of new nickel-based catalysts, targeting higher deoxygenation levels. In the next part of this study, four nickel-based catalyst were synthesized by wet impregnation and evaluated for the hydrotreatment of beech wood fast pyrolysis bio-oil. The catalysts were supported in silica and zirconia and the influence of copper as promoter was studied. Among them, nickel-silica was the most active for hydrodeoxygenation, reducing the oxygen content of the upgraded beech wood fast pyrolysis bio-oil by more than 50 %. The highest degree of water removal as well as low gas and char production were also considered good properties attributed to this catalyst. The investigation on repeated cycles of hydrotreatment with the same catalyst showed a remaining activity even after the fourth reuse, in which 43 % of oxygen was removed. Thus, based on the results obtained with Ni/SiO2, this catalyst was selected together with nickel-chromium catalyst to be used for hydrotreatment of fast pyrolysis bio-oil from residual biomass, as until this point the study had considered only wood-based fast pyrolysis bio oil. Based on the studies so far, the integration of hydrotreatment into a thermochemical conversion route of residues in a sugarcane refinery was proposed. For that, the study encompassed sugarcane bagasse characterization, fast pyrolysis and hydrotreatment of the so derived bio-oils with nickel-chromium and nickel-silica catalyst. The detailed investigation of the bagasse and the fast pyrolysis bio-oil compositions allowed the correlation of the biomass building blocks with the monomers obtained. The hydrotreatment showed that nickel-chromium showed highest activity for organic acids conversion, as previously observed with beech wood bio-oil, whereas nickel-silica revealed more active for conversion of aromatics. Hydrodeoxygenation of 43.3 % was obtained with nickel-silica. Although both catalysts demonstrated to be active at the conditions evaluated, the high viscosities of the upgraded oils in comparison to those obtained from fast pyrolysis showed that polymerization took place and must be further investigated in detail, as it is one of the limiting factors for further application of fast pyrolysis bio-oil hydrotreatment. Overall, this studied showed to be very promising and future studies are planned. In the final part of the thesis, both high loaded nickel-based catalysts studied in the first chapters were selected for a detailed investigation in a continuous operated tricked bed hydrotreatment reactor, due to the similar nickel concentration, nickel particle size and support. The selection of both catalysts aimed to investigate the influence of sulfur on long term catalyst deactivation and the role of chromium in catalyst deactivation. Both catalysts were active for conversion of model substances over more than 48 h of reaction time. By the presence of sulfur, the selectivity of both catalysts changed, mainly towards alkene formation, while the activity remained in the same range. Formation of Ni3S2 was observed for both catalysts, but the highest intensity in the diffraction peak of metallic nickel in the nickel-chromium catalyst might be an indication of higher resistance to sulfur poisoning in comparison to Ni catalyst. In general, the catalysts were active for the conditions tested, although the hydrogenation activity was compromised by sulfur poisoning. Overall, all the catalysts tested in this study were active for hydrotreatment of fast pyrolysis bio-oils. If only stabilization of reactive compounds such as aldehydes and furfurals is required, all of them could be considered suitable candidates. In terms of hydrodeoxygenation activity, Ni/SiO2 showed the highest performance, while nickel-chromium showed to be the most active for conversion of organic acids and superior hydrogenation capacity than Ni/SiO2.

Chapter 13 - Thermochemical conversion of microalgal biomass

India generates approximately 500 million tons of agricultural crop residues per year. This crop residue (waste) can be converted into fuel by using thermo-chemical and bio-chemical conversion routes. Thermo-chemical conversion routes mainly include gasification, pyrolysis, and liquefaction. In recent years, the pyrolysis technology for the production of bio-oil is gaining attention globally, due to its simple and efficient conversion techniques. This paper provides the updated review of bio-oil production mainly from agricultural crop residues and focuses on the different bio-oil production techniques such as fast pyrolysis and hydrothermal liquefaction; the reactor used for bio-oil production, properties, and application of bio-oil. The bio-oil produced from agricultural residues has a heating value of between 17-21 MJ/kg, exactly half of the diesel fuel. The properties of bio-oil showed the potential ability to be used as fuel in many applications such as boiler, furnaces, and diesel engines.

India generates approximately 500 million tons of agricultural crop residues per year. This crop residue (waste) can be converted into fuel by using thermo-chemical and bio-chemical conversion routes. Thermo-chemical conversion routes mainly include gasification, pyrolysis, and liquefaction. In recent years, the pyrolysis technology for the production of bio-oil is gaining attention globally, due to its simple and efficient conversion techniques. This paper provides the updated review of bio-oil production mainly from agricultural crop residues and focuses on the different bio-oil production techniques such as fast pyrolysis and hydrothermal liquefaction; the reactor used for bio-oil production, properties, and application of bio-oil. The bio-oil produced from agricultural residues has a heating value of between 17-21 MJ/kg, exactly half of the diesel fuel. The properties of bio-oil showed the potential ability to be used as fuel in many applications such as boiler, furnaces, and diesel engines.

CatLiq – High pressure and temperature catalytic conversion of biomass: The CatLiq technology in relation to other thermochemical conversion technologies

Chapter 13 - Thermochemical conversion of algal biomass

Increasing demand for renewable feedstock‐based biofuels is driving the interest and rapid development of processes to produce fuels and chemicals from biomass‐generated syngas. Biomass is gasified to produce syngas that can be converted via thermochemical routes to fuels and chemicals such as alcohols, olefins, and fuel grade hydrocarbons. An alternate route to produce liquid products from syngas is through gas fermentation, a hybrid thermochemical/ biochemical process. Biomass gasification, thermochemical syngas conversion routes, and gas fermentation are described including a comparison for converting biomass to ethanol via thecurrent thermochemical route versus gas fermentation. © 2012 American Institute of Chemical Engineers Environ Prog, 2012

The ever-increasing environmental concerns and fuel demands along with population rise have prompted for better and efficient technologies for biofuel production. The second-generation biofuel technologies come to rescue the agricultural waste in the form of lignocellulosic biomass to convert it into fuels. The problem is with the efficiency with which they are produced. The techno-economic assessment gives somewhat precise estimate about the production efficiency of the technologies. In the present chapter, the techno-economic assessment studies of different second-generation biofuel technologies covering the pre-treatment, hydrolysis, and fermentation steps are summarized. The thermochemical conversion of the biomass has been discussed in short along with its techno-economic assessment analysis. In thermochemical conversion technologies, syngas to distillates has become an outdated technology, which is preceded by other gasification technologies such as flash pyrolysis and advanced Fischer–Tropsch reactions. In the pre-treatment of biomass technologies, the diluted acid pre-treatment is the most favored type of pre-treatment adopted for the conversion of biomass. The other technologies such as SO2 pre-treatment technologies ultimately mark a higher price of the product as the charges for storage and transportation of gas has become costly. In the hydrolysis step, the simultaneous saccharification fermentation holds the advantage for being economically efficient, but as for industrial use the separate hydrolysis and fermentation holds the upper hand. The major problem arising with the former is the control of optimized conditions with hydrolysis requiring higher temperature relative to fermentation. This book chapter also covers literature surveys of different topics related to techno-economic assessment of second-generation biofuel technologies through Web of Science. Although the research on literature of all the topics concerned was performed, only results with substantial publications are presented.

<p>Agricultural biomass, including lignocellulosic residues and algal feedstocks, represents an abundant renewable resource with potential for sustainable energy production and environmental remediation. This review systematically explores the latest research on turning agricultural wastes into the agricultural circular economy via thermochemical conversion techniques. Biochar and hydrochar are two of the most frequently reported products, with applications that enhance crop yields by approximately 19.9–36.9% and contribute to soil improvement and pollutant remediation. Studies employing machine learning (ML), life cycle assessment (LCA), and techno-economic analysis (TEA) demonstrate the effectiveness of these approaches: ML-optimized biochar can reach specific surface areas up to 400.0 m<sup>2</sup>/g, immobilize heavy metals in soil with efficiencies over 90.0%, and remove contaminants from wastewater with efficiencies of 84.0–90.0% for heavy metals and 96.5% for organic pollutants. LCA and TEA results confirm notable environmental and economic benefits, including greenhouse gas emission reductions of 1.5 to 3.5 tCO<sub>2</sub>-eq per ton and production costs as low as $116.0/ton for biochar and $30.0/ton for hydrochar. These findings provide a solid foundation for integrating thermochemical conversion into circular economy frameworks and advancing agricultural sustainability.</p>

Thermochemical conversion of microalgal biomass for biofuel production

An overview of biomass thermochemical conversion technologies in Malaysia