Bio-oil Recovery Research Articles

A simple synthesis of bio-based cathode catalyst of microbial fuel cell with bio-oil recovery through pyrolysis of defatted yeast-biomass

Biomass of plant, yeast and bacterial origin is a promising source of activated biochar or carbon for electrode and catalytic material applications, as it is abundant, diverse, and inexpensive. In this work, the defatted biomass of Meyerozyma caribbica, an oleaginous yeast, was used as the feedstock for biochar production. Activated yeast biochar that was synthesized by using KOH in a single-step one-pot process carried out at 700 °C was found to have a honeycomb-like structure with a surface area of around 412 m2/g. The porous activated-biochar exhibited good electrical properties when applied as a cathode-catalyst material of a microbial fuel cell (MFC). Both coulombic and COD removal efficiencies increased by 1.9 and 1.3 times, respectively, as compared to bare carbon-felt as the cathode. In contrast, the internal resistance of the MFC using activated-biochar-based cathode decreased by 2.6-fold as compared to MFC using carbon felt as cathode. The investigation suggested that defatted yeast-based modified bio-charcoal could be a promising carbon-enriched biomaterial for synthesizing cathode catalyst for application in MFCs. This one-pot process of synthesizing cathode catalyst is based on a net zero-discharge approach with concomitant bio-oil recovery.

Experimental study on microwave pyrolysis of eucalyptus camaldulensis leaves: a promising approach for bio-oil recovery

Experimental study on microwave pyrolysis of eucalyptus camaldulensis leaves: a promising approach for bio-oil recovery

Study on Process Parameters in Hydrothermal Liquefaction of Rice Straw and Cow Dung: Product Distribution and Application of Biochar in Wastewater Treatment

In this study, rice straw (RS) and cow dung (CD) waste were hydrothermally processed for the recovery of bio-oil and biochar. The hydrothermal experiments were performed in a 5 L capacity reactor under the following process conditions: temperature (240–340 °C), solvent to biomass ratios of 1:1, 1:2, 2:1, 1:3 and 3:1, a time of 1 h and a pressure of 15 bar. The HTL products were characterized via FTIR, SEM and GC–MS (gas chromatography mass spectrometry). It was seen that the maximum bio-oil yield was 32.5 wt% and the biochar yield was 18.5 wt% for the 2:1 RS:CD mixture at a temperature of 320 °C. The bio-oil contained hexadecane, heptadecane, octadecane and other hydrocarbons, and their presence was confirmed by GC–MS. The biochar was analyzed, and it was used in wastewater treatment to remove the colorants. The biochar also showed some promising results in the colorants removal study, with an efficiency of more than 76%.

Slow pyrolysis of buri palm: Investigation of pyrolysis temperature and residence time effects

The enormous environmental impact of the excessive use of the fossil fuels has prompted researchers to search for an environmentally friendly energy source. In this study, buri palm leaves was utilized to produce biochar and bio-oil using slow pyrolysis. The effects of temperature (T), of (300, 500 and 700 °C) and residence time (RS) of (30, 60 and 90 mins) to pyrolysis products were investigated using a self-design fixed bed reactor. Particularly, the effects of these parameters on the proximate analysis, ultimate analysis, and calculated heating value of biochar were conducted. The results showed that the highest yield in biochar of 68% (T = 300 °C, RT = 90 min) while the bio-oil yield of 46% (T = 500 °C, RS = 90 min) was obtained. It was observed that biochar products increased with residence time but decreasing with the temperature while the bio-oil recovery is as both parameters increase. In addition, fixed carbon, volatile matter, ash, carbon, hydrogen and the higher heating value of biochar were significantly affected by the residence time. The calculated lowest and highest higher heating values of biochar were 16.93 MJ/kg at 300 °C for 30 mins and 28 MJ/kg at 700 °C for 30 mins respectively. Finally, this study presented the viability of buri palm leaves as potential option for sustainable alternative energy sources.

Microbial Granule Technology—Prospects for Wastewater Treatment and Energy Production

Recent years have brought significant evolution and changes in wastewater treatment systems. New solutions are sought to improve treatment efficiency, reduce investment/operational costs, and comply with the principles of circular economy and zero waste. Microbial granules can serve as an alternative to conventional technologies. Indeed, there has been fast-growing interest in methods harnessing aerobic (AGS) and anaerobic (AnGS) granular sludge as well as microbial-bacterial granules (MBGS), as evidenced by the number of studies on the subject and commercial installations developed. The present paper identifies the strengths and weaknesses of wastewater treatment systems based on granular sludge (GS) and their potential for energy production, with a particular focus on establishing the R&D activities required for further advance of these technologies. In particular, the impact of granules on bioenergy conversion, including bio-oil recovery efficiency and biomethane/biohydrogen yields, and bioelectrochemical systems must be assessed and optimized.

Catalytic reforming of sewage sludge pyrolysis products over the self-derived char

The catalytic pyrolysis of sewage sludge (SS) over the self-derived char was performed in a lab-scale fixed-bed reactor. The effect of char and catalytic temperature on the product distribution and the evolution of organic nitrogen species (ONSs) in bio-oil were analyzed. Results showed that although the bio-oil yield with char reforming was comparable to the no catalyst case, much aliphatic and less ONSs content were found in the bio-oil, indicating that the bio-oil quality was improved with char reforming. The bio-oil and gas yields were almost constant at low reforming temperature (<500 °C), while the bio-oil yield reduced slightly and the gas yield increased at high reforming temperature (>500 °C). The highest aliphatic (19.78 %) and lowest ONSs (58.30 %) in the bio-oil could be obtained at the reforming temperature of 500 °C. Moreover, at 500 °C, the highest increment of H2 and CO could be found, increased by 49.05 % and 25.36 %, respectively. The ash and demineralization char (d-char) as a catalyst was conducted to investigate the char reforming mechanism. It was found that the synergistic effect of inherent minerals and specific pore structures in char contributed to the recovery of high-quality bio-oil.

Hydrothermal liquefaction of post-consumer mixed textile waste for recovery of bio-oil and terephthalic acid

Fast fashion trends lead to significant quantities of textiles produced and discarded, its waste is incinerated or landfilled due to a lack of recycling technologies for mixed textiles. Recycling of mixed textiles by hydrothermal liquefaction (HTL) is a novel approach to produce bio-oil and monomers, as no prior sorting or color removal is required. Herein, post-consumer polyester (polyethylene terephthalate (PET)) and cotton garments were subjected to HTL to produce bio-oil and terephthalic acid (TPA). The effects of blending ratio of PET and cotton, temperature and alkali catalyst on the product distributions are investigated. A maximum bio-oil yield of 26% was attained at 325 °C for a 95% Cotton/ 5% PET mix under alkali conditions. TPA yields ranged from 48 to 91%, where 50/50% PET/cotton resulted in a higher TPA yield than 95/5% PET/cotton textile wastes. The results obtained contribute to the development of sustainable recycling processes of mixed textiles.

Endogenous bioethanol production by solid-state prefermentation for enhanced crude bio-oil recovery through integrated hydrothermal liquefaction of seaweeds

The present study evaluated the action of endogenous bioethanol produced during solid-state fermentation of Ulva spp. on subsequent hydrothermal liquefaction (HTL). HTL of raw biomass (RB) was compared with HTL of the fermented biomass after bioethanol separation (F-Aqua) and HTL of the whole fermentation broth containing the bioethanol (F-Eth). Optimization of fermentation conditions increased the ethanol yield efficiency (Yeff) and specific ethanol yield (SEY) from 23.55% and 0.120 g g−1 sugar consumed to 43.97% and 0.224 g g−1 sugar consumed, respectively. TGA and FTIR analysis confirmed noticeable changes in the thermal profile and functional groups of the fermented residue with increased volatiles and lower ash content. Among different HTL treatments, F-Eth showed the highest bio-oil yield of 24.96% at 250 °C, which was 37.7% and 39.0% higher than that of RB and F-Aqua, respectively. In addition, hydrocarbons and esters in the bio-oil represented the dominant compounds in F-Aqua and F-Eth, altogether 28.28% and 68.58%, respectively, compared to 17.96% in RB. Economic analysis for a proposed 100 ton year−1 plant confirmed that HTL of the whole fermentation broth containing endogenous bioethanol enhanced the gross energy output to 8.152 GJ ton−1, which represented 4.2-time, 51.1%, and 23.3% higher than individual bioethanol production, individual bio-oil production, and sequential bioethanol/bio-oil recovery, with the highest net annual profit of 29553 US$ compared to 23391 US$ for the sequential production.

Microwave-assisted depolymerization of lignin and a biphasic extraction method for the recovery of bio-oil and phenolic monomers

Alkaline lignin and de-alkaline lignin were depolymerized under microwave irradiation in the presence of formic acid and ethanol to produce bio-oil and phenolic monomers. The amount of formic acid was identified as the most critical factor influencing product yields among variables of temperature, retention time, feedstock concentration, and formic acid to feedstock mass ratio. Formic acid acted as both catalyst and in-situ hydrogen donor and it is economically and environmentally advantageous over metal catalysts. An ethyl acetate-water extraction method was developed, which was suitable to recover bio-oil from the depolymerization of lignin with high ash content. Acidic extraction condition favored the product recovery than neutral or basic conditions, giving bio-oil product with much improved quality. This is attributed to the fact that pH adjustment induced ionization of solutes and thus altered the affinity between the solutes and the extraction solvents. This work also revealed that alkaline and de-alkaline lignin feedstocks gave comparable bio-oil yield (ash-free basis) and chemical composition. The bio-oil derived from the de-alkaline lignin has a lower average molecular mass than the alkaline lignin-based bio-oil, likely caused by the presence of alkaline compounds in the alkaline lignin, which could neutralize some formic acid (FA) catalyst, leading to a reduced degree of de-polymerization with the alkaline lignin.

Algae Biomass as a Potential Source of Liquid Fuels

Algae biomass is perceived as a prospective source of many types of biofuels, including biogas and biomethane produced in the anaerobic digestion process, ethanol from alcoholic fermentation, biodiesel synthesized from lipid reserve substances, and biohydrogen generated in photobiological transformations. Environmental and economic analyses as well as technological considerations indicate that methane fermentation integrated with bio-oil recovery is one of the most justified directions of energy use of microalgae biomass for energy purposes. A promising direction in the development of bioenergy systems based on the use of microalgae is their integration with waste and pollution neutralization technologies. The use of wastewater, another liquid waste, or flue gases can reduce the costs of biofuel production while having a measurable environmental effect.

Integrated approach for enhanced bio-oil recovery from disposed face masks through co-hydrothermal liquefaction with Spirulina platensis grown in wastewater.

Currently, the enormous generation of contaminated disposed face masks raises many environmental concerns. The present study provides a novel route for efficient crude bio-oil production from disposed masks through co-hydrothermal liquefaction (Co-HTL) with Spirulina platensis grown in wastewater. Ultimate and proximate analysis confirmed that S. platensis contains relatively high nitrogen content (9.13%dw), which decreased by increasing the mask blend ratio. However, carbon and hydrogen contents were higher in masks (83.84 and 13.77%dw, respectively). In addition, masks showed 29.6% higher volatiles than S. platensis, which resulted in 94.2% lower ash content. Thermal decomposition of masks started at a higher temperature (≈330 °C) comparing to S. platensis (≈208 °C). The highest bio-oil yield was recorded by HTL of S. platensis and Co-HTL with 25% (w/w) masks at 300 °C, which showed insignificant differences with each other. GC/MS analysis of the bio-oil produced from HTL of algal biomass showed a high proportion of nitrogen- and oxygen-containing compounds (3.6% and 11.9%, respectively), with relatively low hydrocarbons (17.4%). Mask blend ratio at 25% reduced the nitrogen-containing compounds by 55.6% and enhanced the hydrocarbons by 43.7%. Moreover, blending of masks with S. platensis enhanced the compounds within the diesel range in favor of gasoline and heavy oil. Overall, the present study provides an innovative route for enhanced bio-oil production through mask recycling coupled with wastewater treatment.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s13399-021-01891-2.

Influence of extraction solvents on the recovery yields and properties of bio-oils from woody biomass liquefaction in sub-critical water, ethanol or water–ethanol mixed solvent

In this work, the effects of extraction solvents: acetone, ethanol, dichloromethane (DCM) and ethyl acetate (EA), on the yields and characteristics of bio-oil products obtained from liquefaction of rubberwood sawdust (RS) at 300 ℃ for 30 min in water, ethanol or water–ethanol mixed solvent (50/50, v/v) were comparatively studied. When pure water or ethanol was used as the reaction medium, the highest bio-oil yield was obtained by acetone (30.41 wt%) or EA (31.69 wt%), respectively. Besides, significantly higher bio-oil yields were observed in RS liquefaction in water–ethanol mixed solvent with the maximum bio-oil yield of 56.67 wt% obtained by acetone. But ethanol was always the least efficient in recovering bio-oil in all cases. Besides, the elemental analysis showed that DCM was conducive to recover the bio-oil products with lower oxygen contents and the higher HHVs, while the acetone-extracted bio-oils were worse in quality. However, the highest carbon recovery (CR) and energy recovery (ER) were obtained by acetone due to its higher bio-oil yield produced in water–ethanol mixed solvent. As suggested by GC–MS, GPC and TGA analysis, the extraction solvents and reaction mediums both greatly affected the chemical compositions of the bio-oil products. Phenols were dominant in bio-oil products, followed by hydrocarbons, ketones, esters, etc. Acetone tended to extract the bio-oil with larger carbon numbers and molecular weights, which might explain its higher bio-oil recovery yield in water or water–ethanol mixed solvent. DCM was beneficial to recover the bio-oil was more light compounds with smaller molecular weights and lower boiling point distribution. But for the liquefaction in pure ethanol, more similar chemical compositions were observed among different samples when compared to the cases in other reaction mediums.

Effect of fractional condensation system coupled with an auger pyrolizer on bio-oil composition and properties

The effect of fractional condensation on the properties of pyrolytic oil is evaluated by assessing the number of condensation stages and temperatures used in the bio-oil recovery. By evaluating two and three condensation stages with a decreasing temperature profile, an increase in condensation efficiency of 35 % was observed when using three-condensation stages. The two fractions of bio-oil, obtained at 180 °C and 120 °C of condensing temperatures, exhibited a moisture content of 11.15 % and 23.11 % with a liquid yield of 26.1 %, 13.5 %, respectively. After a qualitative analysis, it is suggested that both oil phases could be strong candidates for their use as fuel for heating applications, or for the production of phenolic resins. Moreover, a quantitative analysis of acids and furans was performed on the third bio-oil fraction, mainly composed of water and acids. Interestingly, a majority content of butyric acid was detected, followed by acetic acid, isovaleric acid, formic acid, and propionic acid with concentrations of 93.6 g/L, 39.0 g/L, 32.0 g/L, 11.0 g/L and 9.1 g/L, respectively. Whereas furfural and HMF content quantified in the aqueous fraction reached 2.1 g/L and 1.5 g/L, respectively. Producing different acids present in this fraction appears feasible, which could have future advantages.

Catalytic Hydrothermal Liquefaction of Penicillin Residue for the Production of Bio-Oil over Different Homogeneous/Heterogeneous Catalysts

In this study, penicillin residue (PR) was used to prepare bio-oil by hydrothermal liquefaction. The effects of homogeneous (organic acid and alkaline catalysts) and heterogeneous catalysts (zeolite molecular sieve) on the yield and properties of bio-oil were investigated. The results show that there are significant differences in the catalytic performance of the catalysts. The effect of homogeneous catalysts on the bio-oil yield was not significant, which only increased from 26.09 (no catalysts) to 31.44 wt.% (Na2CO3, 8 wt.%). In contrast, heterogeneous catalysts had a more obvious effect, and the oil yield reached 36.44 wt.% after adding 5 wt.% MCM-48. Increasing the amount of catalyst enhanced the yield of bio-oil, but excessive amounts of catalyst led to a secondary cracking reaction, resulting in a reduction in bio-oil. Catalytic hydrothermal liquefaction reduced the contents of heteroatoms (oxygen, mainly), slightly increased the contents of C and H in the bio-oil and increased the higher heating value (HHV) and energy recovery (ER) of bio-oil. FTIR and GC-MS analyses showed that the addition of catalysts was beneficial in increasing hydrocarbons and oxygen-containing hydrocarbons in bio-oil and reducing the proportion of nitrogen-containing substances. Comprehensive analyses of the distribution of aromatic, nitrogen-containing and oxygen-containing components in bio-oil were also performed. This work is beneficial for further research on the preparation of bio-oil by hydrothermal liquefaction of antibiotic fermentation residue.

Microwave vacuum co-pyrolysis of waste plastic and seaweeds for enhanced crude bio-oil recovery: Experimental and feasibility study towards industrialization

Waste-to-energy is a promising approach to tackle the energy shortage and reduce the environmental pollution. The present study aimed to evaluate the technical and economic feasibility of microwave vacuum co-pyrolysis of seaweeds and low-density polyethylene (LDPE). Although the three studied seaweeds namely; Ulva intestinalis, Sargassum polycystum, and Hypnea valentiae showed similar thermal weight loss profile, U. intestinalis showed the highest biomass and bio-oil yields which resulted in superior bio-oil areal productivity of 30.1 g m−2. Therefore, it was selected for co-pyrolysis with LDPE at different blend ratios. Compared to individual pyrolysis of U. intestinalis, the increase inLDPE ratio enhanced the crude bio-oil production with simultaneous reduction in bio-char yield. The experimental bio-oil yields from co-pyrolysis showed higher values than the corresponding theoretical values, confirming a synergistic effect between the two feedstocks. The bio-oil produced from co-pyrolysis at 75% LDPE blend ratio showed better characteristics compared to the individual pyrolysis. Van Krevelen plot suggested that LDPE produces hydrogen radicals during co-pyrolysis reactions, which increased the H/C ratio and reduced the O/C ratio. GC/MS analysis confirmed that the increase in LDPE stimulates hydrocarbons proportion up to 51.2% at 75% blend ratio with significant reduction in N-containing compounds, carboxylic acids, furans, aldehydes/ketones, saccharides, and phenols. The economic feasibility analysis at a feedstock feeding rate of 11.4 ton h−1 using Aspen Plus showed estimated net profit of 23.17 million US$ for a 20-years life time plant. The present study provides a potential approach for sustainable energy recovery from waste plastic/seaweeds blend using microwave vacuum co-pyrolysis.

Modeling a Sustainable, Self-Energized Pine Dust Pyrolysis System With Staged Condensation for Optimal Recovery of Bio-Oil

This simulation study explores sustainable improvements that could be made to a pine dust pyrolysis system to eliminate total dependence on external electrical energy supply and improve the yield of high-quality dry bio-oil. The components, stoichiometric yield and composition of oil, char and gas were modeled in ChemCAD using data from literature and results from biomass characterization and pyrolysis. A fast pyrolysis regime was used to increase the overall yield of dry oil fraction recovered and the char by-product was utilized to make the system energy self-sufficient. The optimization study focused on the condensation system whose parameters were varied at the provided optimum pyrolysis temperature. The recommended temperature for the primary condenser was 96–110°C which yielded 23.3–29.8 wt% dry oil with 2.4–4.4 wt% water content. The optimum temperature for the secondary condenser was 82°C whose bio-oil (∼2.92 wt%) had a moisture content of 7.5–10 wt% at constant primary condenser temperature between 96–110°C. The third condenser could be operated at ambient temperature. The results were validated using both information reported in literature and results from the previous experimental study. Such a simple model built by careful selection of the model bio-oil components is useful in estimating the optimal parameters for the biomass pyrolysis staged condensation system.

Design improvement and experimental study on shell and tube condenser for bio-oil recovery from fast pyrolysis of wheat straw biomass

In this study, the design improvement was done in a shell and tube condenser for improved heat transfer and condensation of bio-oil vapour. The developed condenser has split shell and segmental baffles, which divide the shell in various zones and condensate collection points. The fast pyrolysis of wheat straw was done and the bio-oil vapour condensate collected from various outlets located at bottom of condenser shell. From experimental results it was found that production of bio-oil increased from 10.2 to 20.8% with increase in cooling water flow rate from 1000 to 2500 L/h; but, further increasing it beyond 2500 L/h provide marginal effects on production of bio-oil. The production of bio-oil increased from 15.2 to 20.7% as sweep gas flow rate was increased from 20 to 40 L/min at 2500 L/h of cooling water flow rate. But, further increase in sweep gas flow rate beyond 40 L/min resulted in to decrease in production of bio-oil. The novelty of this work is development of improved condenser with segmental baffles, which help in fractional condensation of bio-oil vapour, split shell for cleaning of outer surface of the cooling water tubes and compact design of condenser for optimal condensation of bio-oil.

Experimental Investigation on Energy Recovery System for Continuous Biochar Production System

Fossilfuel requirement is the necessity for fulfilling the global energy needs, which is increasing day by day due to this it will drain in future. Bio-energy became as one of the vital alternatives to replace fossil fuel. Thermochemical conversion of biomass for obtaining the bioenergy is getting more popular in the recent time. In the present study, slow pyrolysis is used for bio-energy production from the waste biomass available in the form of crop residues of Groundnut Shell (GS), Chana Straw (CS) and Wheat Straw (WS) using the developed continuous biochar production system (Pratap Kiln) to produce biochar. An energy recovery system consisting of cooling chamber was developed to recover the bio-oil from the waste flue gas (syngas). The pyrolysis of selected biomass was carried out at 450°C and residence time of about 4 min. The yield of biochar and bio-oil and syngas properties were determined. The maximum biochar yield was found in CS feedstock as 35% followed by WS and GS, i.e. 33% and 29%, respectively. The bio-oil recovery in GS, CS and WS was 31%, 26% and 30% respectively, whereas the syngas production was 40%, 39% and 37% respectively.

Two-stage liquefaction of sewage sludge in methanol-water mixed solvents with low-medium temperature

Hydrothermal liquefaction could be a promising technology to convert sewage sludge into bio-oil for energy recovery. In this study, in order to obtain the maximum yield of bio-oil and improve the energy recovery of sludge, the influence of temperature and residence time on the multi-temperature continuously liquefaction of sludge in methanol-water mixed solvents was investigated. The results showed that the two-stage liquefaction significantly affected the yield, elemental composition, higher heating value, energy recovery and chemical composition of bio-oil. By optimizing the reaction conditions of hydrothermal liquefaction, the maximum utilization of sludge resources was realized. The maximum yield (42.2 %) and ester content (41.8 %) of bio-oil were obtained when the reaction conditions were 260 °C, 40 min for the first stage and 340 °C, 40 min for the second stage. The migration and transformation of nitrogen indicated that nitrogen elements were mainly concentrated in the liquid product and the N-heterocyclic compounds are the main forms of nitrogen in bio-oils.

Experimental study on composition evolution of biomass pyrolysis vapors with condensing temperature in a vertical tubular condenser

The experiments on bio-oil recovery in a vertical tubular condenser with two flumes were conducted for speculating the componential distribution of walnut shell pyrolysis vapors during condensation. Bio-oil elements and functional groups from different locations of condenser were compared with each other. Aromatic H and H in phenolic OH were concentrated in the top and middle bio-oil and their percentage were improved with increasing water bath temperature. Ten representative compounds in bio-oil were chosen for quantitative analysis. As water bath temperature increased from 273 K to 353 K, the recovered water decreased by 85% whereas the guaiacol and its derivatives (guaiacols) merely decreased by 40%. Vapor distributions of water, acetic acid, furfural and guaiacols were simulated by the back analysis of bio-oil components. According to the simulated results, tubular condenser can be properly lengthened for promoting the recovery of specific components at high water bath temperatures.