Biomass Combustion Science, Technology and Engineering
7 - Fast pyrolysis of biomass for the production of liquids
Abstract:
This chapter examines the fast pyrolysis of biomass to produce liquids for use as fuels and chemicals. The technology for fast pyrolysis is described and the characteristics of the main product bio-oil. This primary liquid is characterised by the many properties that affect its use. These properties have caused increasingly extensive research to be undertaken to address properties that need modification and this area is reviewed in terms of physical, catalytic and chemical upgrading. Of particular note is the increasing diversity of upgrading methods.
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Animal manure in the context of renewable energy and value-added products: A review
2024, Chemical Engineering and Processing - Process IntensificationAnimal manure has a complex structure and can be considered a lignocellulosic material. Manure management generates greenhouse emissions, mainly N2O and CH4. Currently, efforts are being made for the sustainable use of animal manure to obtain bioenergy and value-added products. This work shows thermochemical and biochemical methods for manure valorization and proposes strategies to mitigate the inherent environmental problems, thus helping to meet the Sustainable Development Goals (SDG), particularly SDGs 7, 9, 12, and 13. The physicochemical properties and high heating values (HHV) of different types of manure are presented and discussed. The HHV follows the order of Thermochemical processes such as pyrolysis, gasification, and combustion were studied. The operating conditions of anaerobic digestion were also studied. Physical, chemical, thermochemical, and biochemical (e.g., with microbial consortia and enzymes) pre-treatments were analyzed to improve the performance of the above processes. Limitations and obstacles in technological applications were identified, such as manure distribution, lack of government incentives, or the presence of antibiotics in manure. Animal manure has a clear potential to produce organic acids, biomaterials, biofuels, and bioenergy. So, bioprocesses or biorefineries using this biomass as a feedstock may be promising in the near future in the context of the bio-economy, helping to increase the production of renewable energy, promoting inclusive and sustainable industrialization, fostering innovation that adds value to the main livestock activities that generate manure, and guaranteeing sustainable consumption and production modalities that allow mitigating the effects caused by the current treatment of manure.
Current perspective for bio-oil production from agricultural residues in commercialization aspect: A review
2023, Journal of Analytical and Applied PyrolysisBecause of the world's rapid population growth and growing technology, the need for energy is increasing sharply, while current energy resources with limited reserves are depleting. To meet the increased need for energy, the manufacture of biofuels from renewable sources (solid waste) offers enormous potential. Bio-oil production is now seen as a prominent possibility as a technology promising the production of drop-in transportation and boiler fuels. The selection of feedstock, characterization and pretreatment, reactor architecture, and selection of process parameters are all critical elements in the conversion of biomass to bio-oil. Several lignocellulosic biomasses have been investigated for bio-oil production by pyrolysis and hydrothermal liquefaction. This paper presents a comparative analysis of these two methods in terms of product output, process efficiency, and significant constraints. Furthermore, the paper discusses certain significant concerns related to bio-oil from biomass, such as bio-oil basics (e.g., features, chemistry), upgradation, application, environmental and economic evaluation.
Carbon emission pinch analysis for shipping fuel planning considering multiple period and fuel conversion rates
2023, Journal of Cleaner ProductionIn the context of achieving carbon neutrality, reducing CO2 emissions has become an essential task for many countries and poses challenges for various industries. With global trade, the shipping industry is overgrowing, bringing economic benefits but also significant CO2 emissions. To achieve the goal of carbon neutrality, the fuel mix of ships needs to be planned appropriately. As an extension of the base method of Carbon Emission Pinch Analysis, this study develops a new Carbon Pinch Point analysis method for shipping fuel planning. Optimising the energy mix of ships in different period is used to reduce CO2 emissions from shipping fuels and achieve the set emission reduction targets. Taking the Zhoushan sea area in China as an example, emission reduction targets are set in three period with a five-year period from the national policy level. The first period (2020–2025) achieves a 14.5% reduction relative to 2020; the second period (2025–2030) achieves a 32.2% reduction relative to 2020; and the third period (2030–2035) achieves a 57.2% reduction relative to 2020. Each period is divided into Scenario 1 (without heat loss), and Scenario 2 (with heat loss), and two options are developed for each scenario by constraining different low-carbon fuels. The study shows that it is more economical to use LNG as an alternative fuel in the first period, requiring an additional 457.74 kt of LNG in Scenario 1 and 225.26 kt of LNG in Scenario 2. Using biodiesel as an alternative fuel in the second period is more economical, requiring an additional 343.55 kt of biodiesel in Scenario 1313.04 kt of biodiesel in Scenario 2. The use of biodiesel as an alternative fuel in the third period is more economical, requiring an additional 371.73 kt of biodiesel in Scenario 1 and 466.23 kt of biodiesel in Scenario 2.
Co-pyrolysis of low-grade bituminous coal and algal biomass in a rotary kiln: Effect of coal/algae ratio and kiln temperature on the yield and composition of the resultant oils
2023, Journal of Analytical and Applied PyrolysisCo-use of coal with biomass does not only help reduce the carbon footprint from coal-based energy generating systems but also creates opportunities of improving the synthesis of liquid fuels and valuable chemicals via simple pyrolysis processes. Co-pyrolysis of a low-grade coal and algal biomass was performed in a rotary kiln with the aim of assessing the effect of coal/algae blending ratio and kiln temperature on the yield and composition of the resultant oils. Current industrial continuous pyrolysis units operate at intermediate pyrolysis heating rates, as such, the rotary kiln used in this study operated in the heating rates range of 100 – 500 ᵒC/min. For a given reactor temperature, the yield of pyrolysis oil increased with an increase in algae loading. For example, at 550 ᵒC, the yields from coal, coal/algae (90/10), coal/algae (80/20), coal/algae (60/40) and pure algae were 6.9%, 9.6%, 15.1%, 16.3% and 40%, respectively. The oil synthesised from coal contained a high proportion of paraffins. On the other hand, the oil synthesised from algal biomass contained a high proportion of fatty acid esters (28.8 – 32.6%) and alcohols (17.6 – 20.8%). The oil synthesised from coal-algae blends contained compounds found in both coal and algae oils with an increased proportion of PAH and PANHs. It was found that for pyrolysis of all samples, an increase in the reactor temperature resulted in an increase in concentration of PAH and PANHs.
Various biomass pyrolysis conditions influence the porosity and pore size distribution of biochar
2023, EnergyBiochar is obtained from the pyrolysis of biomass in the absence of oxygen and has great potential as a sorbent or as a carbon sequestration material. Although numerous studies have investigated biochar characteristics, the biochar porosity and sorption properties obtained with different pyrolysis conditions are still largely unclear. The objective of this study was to determine the interrelationships among temperature, material grain size, heating rate, and retention time, as well as the effects of the interactions of these variables on the surface morphology of biochar made from wheat straw. The sorption, porosity, and pore size distribution of biochars prepared at different pyrolytic temperatures were determined. Elemental analysis, BET-N2 surface area analysis, ICP‒OES, and Fourier transform infrared spectroscopy were used to characterize 19 wheat straw biochars obtained via pyrolysis at different temperatures (500–700 °C), heating rates (20 and 30 °C/min), and residence times (5 and 15 min). Based on a full factorial design method and variance analysis, the optimal conditions for wheat straw pyrolysis and the variables that have a statistically significant effect on biochar quality were determined. A high surface area of 400 m2/g and an average pore size of approximately 2.34 nm were obtained at 700 °C for a grain size of 0.5–1.0 mm at a heating rate of 20 °C/min and a residence time of 5 min.
Local food security impacts of biofuel crop production in southern Africa
2022, Renewable and Sustainable Energy ReviewsBiofuels have been promoted as a renewable energy option in many countries, but have also faced extensive scrutiny over their sustainability. Food security is perhaps the most debated sustainability impact of biofuels, especially in regions such as Sub-Saharan Africa that experience high rates of malnutrition and have been a major destination for biofuel-related investments. This study assesses the local food security impacts of engagement in biofuel crop production using a consistent protocol between multiple crops and sites. We use standardized metrics of food security related to dietary diversity and perceptions of hunger, and focus on feedstock smallholders and plantation workers in four operational projects: a large-scale jatropha plantation (Mozambique), a smallholder-based jatropha project (Malawi) and two hybrid sugarcane projects (Malawi, Eswatini). Collectively these reflect the main feedstocks, modes of production and land use transitions related to biofuel projects in Sub-Sahara Africa. Inverse Probability Weighting analysis indicates that involvement in sugarcane production improved household food security for plantation workers and feedstock smallholders. Conversely, involvement in jatropha production does not have a statistically significant positive effect on household food security for both workers and smallholders. Regression models indicate that the factors driving food security indicator levels vary between study sites. Wealth indicators influence food security indicators in several sites, but the absolute level of income plays a smaller role, while income stability/regularity, access to credit and stable markets for selling sugarcane be important drivers as indicated by the strong effect of proxy variables on indicators.