Production Of Liquid Biofuels Research Articles

Oil yield from Euphorbia tirucalli as an alternative bioenergy source in Tanzania

Due to the worldwide increase in the demands for bioenergy sources to replace fossil fuels. Euphorbia tirucalli oil produced by stems and modified leaves (phylloclades) is a valuable liquid fuel as an alternative energy source for biofuel production. In this study, E. tirucalli oils were extracted from stem barks with varying stem girths (20cm–80cm) and fully grown apical phylloclades. Soxhlet apparatus was used in oil extraction according to Luque de Castro and García (2000). The percentage (%) oil yield was calculated by the weight of extracted oil to the total weight of the dried sample (20g). The study hypothesized that significantly higher oil yields would be obtained from larger stem girths than phylloclades of the same trees in different Agro-Ecological Zones (AEZs). Likewise, the difference in oil yields was higher in the Semi-arid AEZ than in the Southern highland and the Coast AEZs (p > 0.05). Results showed slightly higher oil yields from large stem girths [16.47% ± 0.34%/(20g) max ≡ 82.35% ± 0.34%/(100g) max] than phylloclades [15.7% ± 0.49%/(20g) max ≡ 78.5% ± 0.34%/(100gmax] in different AEZs. Oil yields from Semi-arid [82.35% ± 0.34%/(100g) max and 78.5% ± 0.49%/(100g) max] were slightly higher than Southern highland [79.0% ± 0.34%/(100g) max and 76.4% ± 0.49%/(100g) max] and the Coast [76.4% ± 0.34%/(100g) max and 70.25% ± 0.49%/(100g) max] AEZ. But the difference in oil yields was not significant (p > 0.05). Results exhibited increasing patterns in the percentage (%) oil yields from low (20cm) to larger (80cm) stem girths. High oil yields between stem girths (82.35%) and phylloclades (78.5%) suggest that E. tirucalli oil is suitable for liquid biofuel production as an energy source in Tanzania.

A study on biodiesel production using agricultural wastes and animal fats

Environmental pollution and the depletion of fossil fuels have created a growing interest in the world community for renewable energy. Large-scale production of liquid biofuels is supported by governments. Iran is a developing country that supplies its energy needs from fossil fuels. However, clean energy must be used to prevent environmental pollution and ensure food security. In this study, with a case study of Golestan province as one of the leading provinces in the field of agriculture, the existing capacities in this country have been studied. The results showed that 58,945.95 tons of biodiesel and 527.55 million liters of bioethanol can be produced annually in this province. By creating suitable grounds for the production of this fuel, solving technological problems and the support of the people and the government of this province, it is able to supply 2% of the fuel of the country’s gasoline engines. Also, the produced biodiesel can supply approximately 13% of the province’s diesel. Reports indicate that it has the largest share in the production of liquid biofuels in the agricultural waste sector.

Producing Energy-Rich Microalgae Biomass for Liquid Biofuels: Influence of Strain Selection and Culture Conditions

Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day–night cycles: Nannochloropsis gaditana, a seawater species, and Parachlorella kessleri, a freshwater species. Lipid and carbohydrate production are investigated, as well as cell resistance to mechanical disruption for energy-rich compound release. Nitrogen-depleted N. gaditana showed only a low consumption of energy-storage molecules with a non-significant preference for neutral lipids (TAG) and carbohydrates in day–night cycles. However, it did accumulate significantly fewer carbohydrates than P. kessleri. Following this, the highest levels of productivity for N. gaditana in chemostat cultures at four levels of nitrogen limitation were found to be 3.4 and 2.2 × 10−3 kg/m2·d for carbohydrates and TAG, respectively, at 56%NO3 limitation. The cell disruption rate of N. gaditana decreased along with nitrogen limitation, from 75% (at 200%NO3) to 17% (at 13%NO3). In the context of potentially recoverable energy for biofuels, P. kessleri showed good potential for biodiesel and high potential for bioethanol; by contrast, N. gaditana was found to be more efficient for biodiesel production only.

A review of bio-oil upgrading by catalytic hydrotreatment: Advances, challenges, and prospects

• Two most common biofuels production techniques including fast pyrolysis and HTL arecovered. • The proposed crude bio-oil upgrading approaches are discussed. • Effects of various upgrading parameters on bio-oil HDO are described. • The mechanism for catalyst deactivation and possible solutions are provided. • Chemistry of major bio-oil model compounds during HDO is thoroughly reviewed. Fast pyrolysis and hydrothermal liquefaction (HTL) have been regarded as the most promising thermochemical conversion technologies for liquid bio-fuels production. However, the poor quality of generated crude bio-oils, such as high O and water contents, low thermal stability, and high corrosivity, limits their direct applications as the alternative transportation fuels. Thus, a number of upgrading techniques mainly including chemical and physical methods have been developed. Among them, hydrotreatment like hydrodeoxygenation (HDO) as a well-established technology at petroleum refinery plants has been widely adopted for upgrading of the crude oil obtained from pyrolysis or HTL. In this review, the effects of various upgrading reaction conditions (temperature, H 2 pressure, solvents, residence time, and catalyst) of HDO treatment of real bio-oil and its mode compounds are thoroughly reviewed. In which, the underlying mechanisms for bio-oil HDO are elucidated with a wide range of its model compounds (lignin-derived oxygenates and carbohydrates-derived oxygenates) and the interaction between these model compounds. Moreover, a discussion regarding the HDO of real bio-oil from pyrolysis and HTL is provided, and the technical/operating problems for the catalytic HDO and the possible solutions are presented. Finally, the important knowledge gaps and future directions are addressed for further investigations.

Candlenut oil: review on oil properties and future liquid biofuel prospects

The rapid depletion of diesel fuel, increasing energy demand, and environmental pollution concerns are increasing worldwide interest in the production of liquid biofuels. Biofuel (bio-aviation and biodiesel) is a potential and plausible alternative to diesel fuel to substantially mitigate the environmental impact of future energy demand. Non-edible crop oil is viewed as a potential feedstock for liquid biofuel production owing to the massive demand for edible oil as a food source. However, the major limitation of utilizing non-edible crop oil for biodiesel production is the cost due to the high price of feedstocks and the limited supply of large-scale biodiesel production. Candlenut trees can grow in harsh and arid climates due to low moisture requirements. Therefore, candlenut can be cultivated in the most unused lands, particularly in developing countries along coasts and riverbanks and in deserts and other wastelands unsuitable for edible crops. Additionally, candlenut seed contains a high amount of oil (30%-60%). Thus, candlenut oil is a promising source for commercial biodiesel production. The present study was conducted to review the possibilities and challenges of utilizing candlenut as a potential feedstock for biodiesel production. Additionally, several important aspects related to candlenut oil processing, such as extraction technology, physicochemical properties, biodiesel production technologies, and advantages and limitations of candlenut biodiesel production are discussed.

Production of biofuel 2,5-dimethylfuran using highly efficient single-step selective hydrogenation of 5-hydroxymethylfurfural over novel Pd-Co/Al-Zr mixed oxide catalyst

Sustainable and cleaner production of liquid biofuel 2,5-dimethylfuran (DMF) is in great demand. Because of its water insolubility, high boiling point, and high energy density, DMF seems to be a promising liquid biofuel. Selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-DMF can be achieved using novel catalysts and is presented here. In this study, a series of Al-Zr mixed oxide catalysts (AZMO) were prepared by co-precipitation and hydrothermal techniques. AZMO catalyst prepared by the co-precipitation method gave higher acidity and surface area. Furthermore, mono and bimetallic M/AZMOCP (M = Ni, Co, Cu, and Pd) catalysts were developed by the impregnation and used for hydrogenation of HMF. The catalytic activity was found in the order of: 2%Pd-5%Co/AZMOCP > 1%Pd-5%Co/AZMOCP > 2%Pd-3%Co/AZMOCP > 1%Pd-3%Co/AZMOCP > 5%Ni-5%Co/AZMOCP > 1%Pd/AZMOCP > 5%Co/AZMOCP > 5%Cu-5%Co/AZMOCP > 3%Co/AZMOCP. It was found that 2%Pd-5%Co/AZMOCP resulted in complete conversion of HMF with 97% yield of DMF at 100 °C and 10 atm H2 pressure. The catalysts were characterized by sophisticated techniques such as FESEM, EDS, XRD, NH3-TPD, ATR-FTIR, BET analysis, HRTEM, TPR, XPS and TGA-DSC. The reaction mechanism was developed based on dual-site Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The catalyst was highly selective and reusable. The overall process is clean and green.

Characterization of biomass produced by Candida tropicalis ASY2 grown using sago processing wastewater for bioenergy applications and its fuel properties

The cost of biodiesel production and the requirement of raw ingredients are the primary constraints that need to be addressed while searching for viable alternative fuels to petrol and diesel. Oleaginous yeasts are gaining wider acceptance as biofuel candidates among oil-rich crops/microbes. The present investigation aimed to integrate the agro-industrial wastewater stream as a nutrient source for the cultivation of oleaginous yeast and to use the resultant biomass and lipid as a feedstock for biofuel synthesis. The yeast biomass grown in sago processing wastewater contained 7.21% moisture content, 69.01% volatile matter, 12.61% fixed carbon, and 11.16% ash content. The ultimate analysis determined the contents of carbon (40.43%), nitrogen (5.14%), hydrogen (4.62%), sulfur (0.54%), and oxygen (49.27%). The heating value of yeast biomass was 16.54 MJ kg−1. The thermal behavior of yeast biomass also suggests its potential use as an energy source. The FTIR spectrum of biomass had major lipid (3030–2800 cm−1 and 1500–1350 cm−1) and carbohydrate (1250 cm−1 and 1000 cm−1) functional peaks. Further FAME profiling revealed that the yeast biomass is primarily composed of stearic, oleic, linoleic, and linolenic acids, similar to the vegetable oils. The fuel characteristics of yeast biodiesel (SV, 168.87 mg KOH g−1; IV, 120 mg I2 100 g−1; CN, 61.79; and KV, 3.16 mm2 s−1) are also within the ASTM standard limits, suggesting that yeast biomass could be a sustainable and economically viable feedstock for both solid and liquid biofuel production.

World market of liquid biofuels: trends, policy and challenges

This paper aimed at studying the current state of development of liquid biofuels’ world market. The authors considered the theoretical bases of liquid biofuels production, their types, disadvantages and advantages. The world experience of introducing stimulation mechanisms of development and their influence on the sectors’ growth is analyzed. In this study’s frame, there is outlined the world leaders in the production of liquid biofuels. The findings represent the peculiarities of state regulation in implementing mandates for creating transport fuels with bioliquids. The current state of investment in the production of liquid biofuels was investigated. The obtained results contribute to the prospects for promoting world production of liquid biofuels to achieve the Paris Agreement’s goals by 2030 under the sustainable development scenario.

Microwave-assisted pyrolysis and distillation of cooking oils for liquid bio-fuel production

The goals of this study are to produce and to characterize bio-oil from pyrolysis and distillation of liquid samples in a microwave reactor. Waste cooking oil (WCO) and fresh cooking oil (FCO) were employed as the feedstocks. A 900 W microwave reactor was modified and filled with 300 g of charcoal. It was used for both pyrolysis and distillation experiments. The pyrolysis experiments were performed at various feed flow rates and temperatures ranging from 0.051 kg/h to 0.306 kg/h and 400 °C–550 °C, respectively. The sample was introduced continuously into the microwave reactor for 60 min. Nitrogen gas was also supplied to ensure pyrolysis condition. The bio-oil product was then distilled to obtain fuel fractions. The results showed that the products yield and bio-oils composition were strongly influenced by pyrolysis temperature and type of cooking oils, while there was almost no influence of feed flow rate under the investigated condition. The bio-oil contained 90−100 wt.% aliphatic hydrocarbons and the rest were aromatic hydrocarbons. The bio-oil produced from WCO contained more than 50 wt.% green-diesel (C10-C15) which was comparable to that from FCO. The green-diesel fraction showed good fuel properties agreement to that of fossil diesels. Overall, microwave-assisted pyrolysis and distillation processes are potential ways to convert problematic WCO into useful liquid bio-fuel and green-diesel fuel.

Ethanol Production Potential of Sweet Sorghum in North and Central Ukraine

Background: Sweet sorghum (Sorghum saccharatum (L.) Moench) is a unique crop with great potential to serve both the food and energy industries. It is due to the possibility of (bio)ethanol production both from the juice and biomass of this crop. The sorghum stems juice contains sugar in the levels similar to that of sugarcane. Besides, low cultivation requirements for the sweet sorghum make this crop even more attractive for sugar and ethanol production. In terms of technology, sweet sorghum is seen as a transitional feedstock for the first to the second generation bioethanol production. However, effective technological development of the plant cultivation and processing in the Northern and Central Ukraine is restrained by the lack of a collection of sweet sorghum genotypes and adapted varieties for its large-scale cultivation. Additionally, no evaluations of potential (bio)ethanol productivity have been performed for this region, which is important for efficient implementation of novel biofuel-producing technologies and for successful development of a green economy. Objective: This research was aimed to create a pool of sweet sorghum genotypes with the involvement of worldwide germplasm, analyze their morphology and breed high-yielding plant lines for the efficient production of liquid biofuels for second-generation bioenergy. Based on that, we also aimed to explore the prospects regarding the efficiency of sweet sorghum cultivation for (bio)ethanol production in the Northern and Central Ukraine. Methods and Materials: A valuable gene pool of S. saccharatum (L.) Moench (41 samples) was created; in particular, high-performance genotypes were created for cultivation under the soil-climatic conditions of Ukraine. The bio-morphological features and the yield potential of the plants were determined and the biochemical composition of the phyto-raw materials was determined in different periods of vegetation, in particular, during the technical ripeness of the above-ground mass of plants. The more productive forms and varieties of sugar sorghum in terms of yield, dry matter content, sugar, and energy value of biomass during flowering and waxy ripeness are highlighted. The technological properties of plant biomass for the production of alternative liquid fuels (in particular, bioethanol) have been analyzed. Importantly, optimal cultivation conditions have been elaborated for the newly created sweet sorghum genotypes, and their productivity has also been evaluated. Moreover, for the first time, a detailed study on potential ethanol yield has been conducted. Results: Sweet sorghum has considerable potential in Ukraine as a new sugar-producing energy crop. The germplasm collection of this crop has been created (41 accessions), including introduced and acclimated genotypes and newly bred lines and varieties. The biological performance of sorghum in Ukraine and plant morphology have been analyzed. The most promising genotypes were used for breeding of new high-productive sweet sorghum varieties. The potential (bio)ethanol yield for different sugar feedstocks (juice, grain bagasse) can reach up to 11423 L/ha in total from juice, grain and bagasse. Conclusion: The estimated values of ethanol productivity are comparable to the results of other similar investigations. In conclusion, a high performance of sweet sorghum in Ukraine can be suggested.

A study on different parameters affecting the saccharification rate of Typha orientalis pretreated with Ionic Liquids (ILs) and microwave irradiation for bioethanol production by using response surface methodology

This study investigates the saccharification rate of Typha orientalis pretreated with Ionic liquids 4-(3-Methyl−1-imidazolio) − 1-butanesulfonic acid hydrogen sulfate [BSO3HMIM] [HSO4], combined with microwave irradiation for liquid biofuel production. Methods of full factorial experimental design was used to explore the factors affecting the conversion rate of fibers into fermentable sugar. The results from Plackett-Burman Design (PBD) shows that efficiency on the saccharification rate of Typha orientalis was in the order of microwave power > solvent volume > catalyst > reaction time. From the results obtained, optimum parameter was determined by Central Composite Design (CCD) where the highest saccharification rate attained was 52.9%.

Food Security in the Context of Liquid Biofuels Production

A crucial factor that determines the development of production and consumption markets for biofuels is the choice of raw materials that can ensure the highest possible production efficiency, the lowest cost and the smallest emission of harmful substances to the atmosphere during all production stages. Considerations underlying the development of biofuel production have been discussed as well as the theoretical mechanisms linking the generation of biofuels to the level of production and the variability of prices of agricultural raw products. The aim of this study has been to identify the scale at which energy raw materials originating from agriculture are used for liquid biofuels production and to explore their impact on food security. The study used public statistical data (OECD-FAO and IndexMundi). The time span of the analysis was from 2005 to 2018. First-generation biofuels based on food raw materials (cereal grains, root crops, sugarcane and vegetable oils) are becoming increasingly competitive with food production recent years have been a period of the dynamic growth in production of liquid biofuels. In 2018, the global production of these substances reached 167.9 billion litres (bioethanol and biodiesel together), consuming 16.1% of maize grain, 1.7% of wheat grain, 3.3% of grain of other feed grains and 13.5% of vegetable oil.

(Invited) Increasing Biogas to Liquid Fuel Yield By Solid Oxide Co-Electrolysis of Biogas CO2 Fraction

OxEon Energy, LLC (OxEon) plans to demonstrate production of liquid hydrocarbon fuels using both the methane and CO2 generated in a food waste digester operated by the Environmental Products & Technologies Corporation (EPT). The EPT food waste digester in Burley Idaho sells produced biogas into a natural gas pipeline after separating and venting the bio-CO2. This project will convert the bio-methane to synthesis gas (syngas, as CO & H2) using a non-thermal plasma catalyzed autothermal reformer. To achieve high bio-carbon utilization, an OxEon high temperature solid oxide co-electrolysis (HTCE) system will electrochemically generate additional syngas from the bio-CO2 combined with steam raised by cooling the Fischer Tropsch (FT) reactor. Syngas from the reformed methane and co-electrolyzed CO2, will be converted to liquid fuels using an OxEon developed FT reactor. Each of the technology components have been field tested independently and will be combined for the first time in this project. The project outcome will be an engineering scale demonstration of liquid hydrocarbon bio-fuel production achieving > 50% conversion to liquids of the biogenic carbon in both CH4 & CO2 produced by an anaerobic digester.Each of the three technology elements of the integrated engineering test incorporates numerous innovations. The plasma reactor is designed to be fuel flexible, sulfur tolerant, and economically scalable to small, distributed bio-gas resources. It is also very efficient using a low power non- thermal plasma. High temperature solid oxide electrolysis has demonstrated efficiency at the thermodynamic limit as shown by analysis and testing at DOE and NASA laboratories, and is unique in its ability to co-electrolyze steam and CO2 directly to syngas. The HTCE stacks use innovations proven for the NASA Mars 2020 project which required exceptional ruggedness and effective high temperature seals. The FT reactor enables economical fabrication of smaller size synthetic fuel plants designed to match the scale of distributed renewable biomass resources. This is achieved with large diameter standard piping combined with a novel internal thermal management structure.The status of the technology elements and the planned engineering demonstration will be presented.This work is supported by the Bioenergy Technologies Office of the US Department of Energy.

Low-temperature catalytic conversion of alkaline sewage sludge bio-oil to biodiesel: Product characteristics and reaction mechanisms

Sewage sludge is a promising biomass alternative for the production of liquid biofuels. In this study, bio-oil derived from the fast pyrolysis of domestic sewage sludge was upgraded in a micro Robinson–Mahoneyreactor at 4 MPa and 260 °C, and in the presence of hybridized Ni/HZSM-5 catalyst and ethanol. Fourier transform infrared and gas chromatography-mass spectrometry analyses were used to identify the functional groups and chemical components of raw and upgraded sewage sludge bio-oil. Results showed that catalytic upgrading reduced the relative content of acids, aldehydes, phenols, ketones, and nitrogenated compounds in the pyrolytic bio-oil. Thus, the main components of the upgraded bio-oil product included esters (48.59%), alkanes (10.12%), aromatics (9.38%), and alkenes (5.08%). Water and nitriles in the raw pyrolytic bio-oil together with in-situ-produced carbon oxides helped in the esterification of raw bio-oil. Reaction mechanisms such as nitrile hydrolysis, hydrogenation, and esterification were proposed to elucidate the conversion of the non-acidic pyrolytic bio-oil into ester-dominating upgraded bio-oil. Overall, upgrading sewage sludge pyrolytic oil is crucial to produce high-quality diesel-range biofuel.

Balanced Xylan Acetylation is the Key Regulator of Plant Growth and Development, and Cell Wall Structure and for Industrial Utilization.

Xylan is the most abundant hemicellulose, constitutes about 25–35% of the dry biomass of woody and lignified tissues, and occurs up to 50% in some cereal grains. The accurate degree and position of xylan acetylation is necessary for xylan function and for plant growth and development. The post synthetic acetylation of cell wall xylan, mainly regulated by Reduced Wall Acetylation (RWA), Trichome Birefringence-Like (TBL), and Altered Xyloglucan 9 (AXY9) genes, is essential for effective bonding of xylan with cellulose. Recent studies have proven that not only xylan acetylation but also its deacetylation is vital for various plant functions. Thus, the present review focuses on the latest advances in understanding xylan acetylation and deacetylation and explores their effects on plant growth and development. Baseline knowledge about precise regulation of xylan acetylation and deacetylation is pivotal to developing plant biomass better suited for second-generation liquid biofuel production.

Simultaneous thermal liquefaction of sugarcane bagasse and esterification with ethanol and fusel oil: One-Step process for biofuel production

Sugarcane bagasse is an abundant residue from the ethanol/sugar industries and its liquefaction can be a low-cost process for the production of liquid biofuels. However, the resulting biocrude has high acidity, which requires an upgrading before being used. In this study, ethanol and fusel oil, which is the heavy residue of ethanol distillation made up of higher alcohols, were used as solvents for the liquefaction of bagasse. The 1:10 biomass:solvent ratio mixture was used at 300 °C for 30 min and (10 bar) N2 atmosphere. A mixture of both solvents was also tested to make a comparative study. The process with ethanol showed 72% bagasse conversion, but the best result showed 91% with fusel oil, producing a low biochar content (9%). After the distillation of the liquid product, a biocrude with high combustion heat (30.6 MJ.kg−1) and rich in esters was obtained. The results of GC/MS revealed the greater presence of esters with substituted isoamyl groups (51.2%) and, to a lesser extent, phenolic compounds (2.5%). The biochar has a higher heating value of 30 MJ.kg−1 and special thermal stability, suitable for application as a solid fuel. The biocrude was mixed with marine diesel (5%) and the properties of the mixture were evaluated, without relevant modifications. This innovative process showed the use of two residues, bagasse, and fusel oil, to produce a biofuel to be used with different types of diesel, with economic and environmental gains in a cycle economy for the ethanol industry.

СУЧАСНИЙ СТАН ТА ПЕРСПЕКТИВИ ВИРОБНИЦТВА БІОНАФТИ МЕТОДОМ ШВИДКОГО ПІРОЛІЗУ З ЛІГНОЦЕЛЮЛОЗНОЇ БІОМАСИ

Стаття присвячена питанням сучасного стану отримання екологічно чистого рідкого біопалива (біонафти) з лігноцелюлозної біомаси шляхом її термохімічної конверсії, а також перспективам розвитку цього напрямку найближчим часом. В даний час термохімічна конверсія (швидкий піроліз) рослинної біомаси, яка містить в своєму складі велику кількість лігноцелюлози, в рідке біопаливо, є одним з напрямів залучення нетрадиційних джерел енергії в енергобаланс України. У зв'язку з цим необхідно оцінити сучасний стан розвитку промислового отримання рідкого біопалива з лігноцелюлози рослинної біомаси і подальші перспективи в цій галузі біоенергетики. Для цієї мети на основі вивчення наукової бібліографії, яка торкається проблеми виробництва рідкого біопалива, проаналізовано вже наявний досвід різних країн щодо промислового виробництва біодизельного пального методом швидкого піролізу і показана можливість використання лігноцелюлозної біомаси в якості сировини для його отримання. Так само наводяться відомості щодо технологій, які вийшли на промисловий рівень. Встановлено, що технологія отримання біопалива з лігноцелюлозної біомаси має широке поширення в багатьох країнах світу. В роботі наводиться опис технологічної схеми швидкого піролізу деревини та його основних етапів. Показано, що під час використання технології термохімічної конверсії лігноцелюлозної біомаси можна отримувати високоякісний вуглеводневий продукт - біонафту, і дається опис основних переваг цього продукту. В результаті роботи встановлено, що технологія виробництва біонафти з лігноцелюлозної біомаси методом швидкого піролізу має широкі перспективи для подальшого розвитку.
 Результати, отримані авторами статті, можуть бути використані у подальшому вивченні питань, пов'язаних з термохімічною конверсією біомаси в рідке біопаливо. Бібл. 12.

Production and characterization of liquid biofuels from locally available nonedible feedstocks

AbstractMandarin (Citrus reticulata) seeds were exploited as possible nonedible feedstock for the synthesis of liquid biofuels, namely, biodiesel and bio‐oil via alkali–alcoholysis and pyrolysis routes, respectively. The alkali–alcoholysis reaction of mandarin seed oil with an equivalent mixture of methanol–ethanol alcohols was examined and optimized by analysis of variance (ANOVA). The best experimental yield of biodiesel (95.55 ± 1.55 wt.%) was comparable with the predicted yield (95.0 wt.%). Also, analysis by one‐way ANOVA showed that the selected variables were statistically significant. The 1H NMR spectroscopy asserted the transformation of the oil to biodiesel. Also, the evaluated properties of the biodiesel were in the range given by ASTM D6751 standards. The mandarin citrus seeds have also subjected to the thermal pyrolysis process in a fixed‐bed reactor to obtain bio‐oil and bio‐char. The influence of the pyrolysis temperature, time, feed particle size, and heating rate on the bio‐oil yield was optimized. The highest yield of bio‐oil (52.34 ± 1.25 wt.%) was attained at 475°C for 60 min using 70 mesh particle size of the feed with a heating rate of 20°C/min. The bio‐oil was analyzed by Fourier transform infrared spectroscopy (FTIR), 1H NMR spectroscopy, and ultimate analysis. The bio‐oil derived from MCS has an empirical formula of CH1.88 O0.16 N0.012 S0.0005 with 37.96 MJ/kg of heating value. The elevated carbon level, low oxygen content, and high calorific value (25.45 MJ/kg) of the attained bio‐char suggest its suitability as a solid fuel. Also, the obtained bio‐char can be utilized for preparing carbon adsorbent as a result of its good surface area.

Integration of hydrothermal liquefaction and carbon capture and storage for the production of advanced liquid biofuels with negative CO2 emissions

The technical and economic feasibility to deliver sustainable liquid biocrude through hydrothermal liquefaction (HTL) while enabling negative carbon dioxide emissions is evaluated in this paper, looking into the potential of the process in the context of negative emission technologies (NETs) for climate change mitigation. In the HTL process, a gas phase consisting mainly of carbon dioxide is obtained as a side product driving a potential for the implementation of carbon capture and storage in the process (BECCS) that has not been explored yet in the existing literature and is undertaken in this study. To this end, the process is divided in a standard HTL base and a carbon capture add-on, having forestry residues as feedstock. The Selexol technology is adapted in a novel scheme to simultaneously separate the CO2 from the HTL gas and recover the excess hydrogen for biocrude upgrading. The cost evaluation indicates that the additional cost of the carbon capture can be compensated by revenues from the excess process heat and the European carbon allowance market. The impact in the MFSP of the HTL base case ranges from -7% to 3%, with -15% in the most favorable scenario, with a GHG emissions reduction potential of 102-113% compared to the fossil baseline. These results show that the implementation of CCS in the HTL process is a promising alternative from technical, economic and environmental perspective in future scenarios in which advanced liquid biofuels and NETs are expected to play a role in the decarbonization of the energy system.

Techno-Economic and Environmental Assessment of Biomass Gasification and Fischer–Tropsch Synthesis Integrated to Sugarcane Biorefineries

Large-scale deployment of both biochemical and thermochemical routes for advanced biofuels production is seen as a key climate change mitigation option. This study addresses techno-economic and environmental aspects of advanced liquid biofuels production alternatives via biomass gasification and Fischer–Tropsch synthesis integrated to a typical sugarcane distillery. The thermochemical route comprises the conversion of the residual lignocellulosic fraction of conventional sugarcane (bagasse and straw), together with eucalyptus and energy-cane as emerging lignocellulosic biomass options. This work promotes an integrated framework to simulate the mass and energy balances of process alternatives and incorporates techno-economic analyses and sustainability assessment methods based on a life-cycle perspective. Results show that integrated biorefineries provide greenhouse gas emission reduction between 85–95% compared to the fossil equivalent, higher than that expected from a typical sugarcane biorefinery. When considering avoided emissions by cultivated area, biorefinery scenarios processing energy-cane are favored, however at lower economic performance. Thermochemical processes may take advantage of the integration with the typical sugarcane mills and novel biofuels policies (e.g., RenovaBio) to mitigate some of the risks linked to the implementation of new biofuel technologies.