Liquefaction Technique Research Articles

Hydrothermal liquefaction of southern yellow pine with downstream processing for improved fuel grade chemicals production

The hydrothermal liquefaction (HTL) technique for liquefying lignocellulose biomass feedstock is often associated with low biocrude yield and poor fuel properties. This study examined the HTL of southern yellow pine sawdust and the hydrotreatment (HYD) of produced biocrudes in an effort to address these challenges. Pine HTL treatment was performed within water and water–ethanol mixed reaction medium at 250, 300, and 350℃ temperatures using metallic iron (Fe) as a catalyst. The rising reaction temperature in a water medium and increasing ethanol content in a mixed reaction medium were found to be effective in enhancing the biocrude yield from the non-catalytic pine HTL process. Maximum non-catalytic biocrude yield of 18 wt.% was produced in water at 350℃, whereas the ethanol and water (1:1 on mass basis) mixture generated the highest biocrude yield of 34 wt.% at 300℃ without any catalyst. The iron catalyst facilitated a maximum of 29 wt.% of biocrude yield as opposed to 18 wt.% without the catalyst at 350℃ in water. The use of an iron catalyst also raised the calorific value of produced biocrudes by 2.5–14 % within 250-350℃ in both water and water–ethanol media. The catalytic and non-catalytic biocrude products were chosen to undergo HYD treatment at 400 °C under high hydrogen pressure (initial 1000 psi) using an alumina-supported cobalt-molybdenum catalyst. The HYD treatment reduced the oxygen content of upgraded oils by 36–60 % compared to the parent HTL biocrudes with 35–37 MJ/kg calorific values. The simulated distillation detected the maximum gasoline range compounds in upgraded oil from catalyst and water–ethanol conditions, whereas the GC–MS analysis revealed the production of increased aromatic hydrocarbons in all upgraded HYD oils. This work has demonstrated the potential of ethanol and inexpensive iron catalyst in enhancing the biocrude production from pine, which could be upgraded to better fuel using the HYD process.

Lignin with Tunable and Predictable Yield and Molecular Properties

To control and predict lignin properties remains very challenging due to the complexity of chemical structures and recovery methods of lignin. Recently, an acid-catalyzed one-pot liquefaction technique was developed to produce Kraft lignin with improved molecular uniformity directly from black liquor. Herein, we investigated the effects of the liquefaction parameters (pH, reaction temperature, and reaction time) on the yield, molecular weights, polydispersity, and quantities of different types of hydroxyl groups of the Kraft lignin using the Box–Behnken response surface methodology (RSM). Computational models were generated and refined to establish the relationships between the liquefaction parameters and the Kraft lignin properties. The results showed that pH was the most influential factor followed by the reaction temperature affecting the properties of the Kraft lignin. The yield, molecular weight, and polydispersity were found to be more predictable (R(pred)2 values of 87.5–91.5%) than the type and quantity of hydroxyl groups (R(pred)2 values of 0) of the Kraft lignin. Additionally, the weight average molecular weight (Mw) could be used as a reliable predictor for both the number average molecular weight (Mn) and the polydispersity of the Kraft lignin, which was confirmed by both the experimental and the computational approaches. Such tunable and predictable molecular properties of the lignin may be associated with the combination of acetic acid, subcritical methanol, and one-pot method. This study provided insights into understanding, predicting, and even customizing the properties of the lignin products.

Performance of Structural Alloys in Bio-oil Production, Upgrading, and Storage Systems

Selection of corrosion-resistant, cost-effective structural materials for the process and containment vessels required for the production, upgrading, and storage of biomass-derived oils has been the subject of study in our laboratory for many years. The wide variety of biomass resources and the many liquefaction techniques and processing conditions result in products with a broad range of properties and compositions. This paper will address the materials issues in three distinct areas. In production, materials are exposed to temperatures that range from 350 to 550 °C depending upon the process. Generally, austenitic stainless steels have performed reasonably well, although thicker oxide scales and intergranular attack have sometimes been observed. For storage and transport of the bio-oil products, temperatures experienced by the containment materials are not expected to exceed 50 °C. Our studies have shown that most raw bio-oils contain significant concentrations of organic acids, and low-molecular-weight organic acids were quite corrosive to carbon and low alloy steels. For some applications, subsequent processing is required, which includes hydrotreating or co-processing with a petroleum-derived liquid. These processes utilize a catalyst that requires periodic retreatment with a sulfidizing gas, and the exposure to this gas at elevated temperatures can cause appreciable corrosion to the more common austenitic stainless steels. The materials considered most cost-effective and sufficiently corrosion-resistant for each of these environments were identified.

Effect of biomass liquefaction on glucose and xylose prices predicted by National Renewable Energy Laboratory biochemical sugar model

AbstractThe National Renewable Energy Laboratory (NREL) published a model in 2017 that enables the minimum selling price of lignocellulosic sugar to be calculated. The model can be modified to suit any biomass feedstock and operational design. In the present case, the model is used to understand the economics of a process configuration that incorporates liquefaction as a preprocessing step in corn‐stover‐fed biorefinery. This study demonstrates a quantitative approach utilizing an existing biorefinery setup to simulate the biomass liquefaction technique while estimating the price of the resulting sugar product. The objective is to understand whether the addition of liquefaction methodology – and the substitution of acid pretreatment – can reduce the cost of lignocellulosic sugars. The reason for setting up a liquefaction unit at the start is to reduce the yield stress of biomass slurry so that the flow remains unrestricted downstream. The liquefaction process is also unique because it uses no chemicals and saves the cost of pretreatment. The pretreatment step is bypassed because the output of liquefaction can be fed into enzyme hydrolysis just after simple cooking. The liquefaction process can be performed in three modes: enzyme, enzyme mimetic, and a combination of enzyme and enzyme mimetic. The results from the BC1707 model indicate the minimum cost for the enzyme liquefaction route. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Insights on the Effect of Heavy Metals on Subcritical Hydrothermal Recycling of Heavy Metal-Contaminated Biomass and Its Derived Porous Carbon Properties Using Cu as a Case

Subcritical hydrothermal liquefaction (HTL) technique has shown great potential in recycling heavy-metal-contaminated biomass derived from phytoremediation and biosorption. However, the effect of heavy metals on the physicochemical characteristics of HTL products and their derivatives has not been elaborated so far. Herein, various Cu content-contaminated derived biomass was recycled by HTL. We found that over 99% of Cu was enriched in hydrochar at 300 °C, enabling us to obtain clean chemicals (e.g., levulinic acid and acetic acid). Furthermore, a large amount of Cu(0) was formed, especially at high temperatures, because HTL products acted as electron donors. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry analysis showed that Cu catalyzed the depolymerization and deoxygenation of macromolecular lignins/carboxylic-rich alicyclic molecule-like compounds, resulting in the production of more levulinic acid. Two-dimensional FTIR correlation spectroscopy analysis indicated that the intensity of C═C increased first, and the intensity of C–O–C decreased later as the Cu content increased. Notably, the low-risk hydrochar could be upgraded into porous carbon (PC) with excellent CO2 capture performance (up to 6.64 mmol/g), whereas Cu enhanced the CO2 capture capacity of PC by increasing its porosity. Undoubtedly, such findings have important implications for recycling heavy-metal-contaminated biomass into high value-added products.

Liquefaction performances of the mixture of paper fibre and LDPE in subcritical water

The waste Tetra pack impose a great pressure on environment. In this paper, we use hydrothermal liquefaction technique to convert it into valuable crude oil. The paper fibre and LDPE were studied in supercritical water at 420 °C, 25 MPa and residence time of 30 min. Effect of paper fibre: LDPE on the crude oil yield, components distribution and high heat value were investigated in depth. Results showed that maximum crude oil yield of 27.33 wt% was obtained at paper fibre to LDPE of 8:2, minimum O/C of 0.094 was obtained at paper fibre to LDPE of 5:5, which reflect that HTL of paper fibre and LDPE had a synergetic effect. And the highest high heat value of the crude oil reach 37.7 MJ/kg at the ratio of 5:5• The CH radicals produced from LDPE chain can promote the hydrogenation reaction that then decrease the production of oxygen-containing groups, and also the broken of C-C bond in lignin will be accelerate, which increased the diesel (C16-C47) compound.

Effect of Cryogenic Treatment on Density, Resistivity and Conductivity of Manganese Used in Lithium-Ion Batteries

Abstract: Refrigeration is one of the core branch in the field of thermal engineering. In other words, we can say that the refrigeration is the sister branch of the thermal engineering or thermal science. The main purpose of refrigeration is to maintain the low temperature than the atmospheric temperature or simply room temperature. In a few decades, the new trends in the field of the refrigeration and air condition has been changed drastically. The need for the development of new refrigeration processes is to achieve possible minimum temperature by the liquefaction techniques such as linde claude system. The new field known as cryogenics is developed in recent few years whose main aim is to achieve the lowest possible temperature in order of -100 to - 1500 C. the cryogenics has a wide veriety of the applications ranging from space research to the medical science which can be supposed as a science fiction in the real life. Our research work is based on the analysis of the cryogenic treatment to the lithium ion battery to improve the performance of the battery for the long period. Keywords: Cryogenics, lithium ion batteries, manganese, density, conductivity

Comparative study of pyrolysis and hydrothermal liquefaction of microalgal species: Analysis of product yields with reaction temperature

Renewable and sustainable biofuel production from algal biomass has been explored vigorously due to the owing potential of overcoming the limitations of first and second-generation biofuel feedstocks. Thermochemical conversion technologies are considered promising routes for bioenergy production from algal biomass and have been extensively investigated over the last few years. This paper aims to review the various pyrolysis (slow, fast, and microwave -assisted) processes and hydrothermal liquefaction (HTL) techniques. The fast pyrolysis is involving a higher heating rate and shorter residence time compared to slow pyrolysis. Microwave-assisted pyrolysis (MAP) is considered a highly efficient process due to uniform heating. Due to a high moisture feedstock, the HTL process is considered the most energy-efficient processing option for algal biomass. In all these processes, the process temperature is considered the most critical parameter affecting product yield. This paper provides a detailed analysis and discussion on the effect of temperature and heating rates on the product (biochar, bio-oil, and syngas) yields for various microalgal species. The process details, different approaches, and process conditions investigated, challenges and recent advancements achieved in both technologies have been discussed in detail that provides useful insights to design a sustainable process and understand the process feasibility.

DOES ASSISTED LIQUEFACTION INSTEAD OF INCUBATION AFFECT SPERM MOTILITY AND MOTILE SPERM RECOVERY IN THE SPERM WASH PROCESS?

The primary purpose of sperm preparation may be to separate motile sperm from seminal plasma as soon as possible and prepare an optimal sample for ART, such as in vitro fertilization (IVF) and intrauterine insemination (IUI). The objective of this study is to evaluate whether an assisted liquefaction technique can replace the traditional method and whether sperm motility and motile sperm recovery is affected. Twenty samples were analyzed using both traditional and assisted liquefaction methods. The assisted liquefaction technique used consisted of adding pre-warmed sperm wash media at 1 to 2x the semen volume to the sample before sample processing. Then liquefaction and viscosity were confirmed by dropping specimen. Half of the sample was liquefied for 15-30 minutes at 37°C outlined by WHO 5th edition. Each sample was then overlaid onto 2 ml of 90% density gradient with no more than 1.5 ml of sample per tube. The sample was centrifuged at 400g for 15 minutes. Supernatant was removed and samples from multiple tubes were combined if needed. After additional wash, a 5 ul aliquot from both group was counted using a pre-warmed MicroCell as a post-wash. The difference between the assisted and traditional liquefaction was assessed for the following parameters: total motile sperm, total motility, and progressive motility by t-test. A p value of < 0.05 was considered significant. The assisted liquefaction resulted in an average increase of 3% for both the total motility and progressive motility and recovered in an average increase of 1.69 million motile sperm although there was not significantly different. Furthermore, sperm were observed to move at a higher velocity in samples processed with the assisted technique than with the traditional by experienced andrologists. Samples processed with the traditional technique were observed to contain more non-motile sperm after processing than those processed with the assisted technique The use of an assisted technique instead of the traditional technique can be used without negatively affecting motility and recovery of motile sperm for ART. An assisted technique can be used to decrease the processing time while continuing to provide a high quality sample. Additionally, an assisted technique may provide a more efficient sample preparation as the seminal plasma is fully diluted resulting in less non-motile sperm and greater progressive motility.

Subcritical Hydrothermal Co-Liquefaction of Process Rejects at a Wastepaper-Based Paper Mill with Waste Soybean Oil

This study used the subcritical hydrothermal liquefaction technique (SHLT) in the co- liquefaction of process rejects at a wastepaper-based paper mill (PRWPM) and waste soybean oil (WSO) for the production of biofuels and bio-char material. PRWPM emits complicated waste composed of cellulose, hemicellulose, lignin, and plastic from sealing film. The waste is produced from the recycled paper process of a mill plant located in central Taiwan. The source of WSO is the rejected organic waste from a cooking oil factory located in north Taiwan. PRWPM and WSO are suitable for use as fuels, but due to their high oxygen content, their use as commercial liquid fuels is not frequent, thus making deoxygenation and hydrogenation necessary. The temperature and pressure of SHLT were set at 523–643 K and 40–250 bar, respectively. The experimental conditions included solvent ratios of oil–water, temperature, reaction time, and ratios of solvent to PRWPM. The analysis results contained approximated components, heating values, elements, surface features, simulated distillations, product compositions, and recovery yields. The HHV of the product occurred at an oil–water ratio of 75:25, with a value of 38.04 MJ kg−1. At an oil–water ratio of 25:75, the liquid oil-phase product of SHTL has the highest heating value 42.02 MJ kg−1. Higher WSO content implies a lower heating value of the oil-phase product. The simulated distillation result of the oil-phase product with higher content of alcohol and alkanes obtained at the oil–water ratio of 25:75 is better than the other ratios. Here, the carbon number of the oil product is between C8–C36. The product conversion rate rises with an increase of the WSO ratio. It is proved that blending soybean oil with water can significantly enhance the quality of liquefied oil and the conversion rate of PRWPM. Therefore, the solid and liquid biomass wastes co-liquefaction to produce gas and liquid biofuels under SHLT are quite feasible.

The effect of enzyme concentration on physcical characteristics of pumpkin (Cucurbita moschata) puree and its dried extract

Pumpkin (Cucurbita moschata) contain many nutritional and biologically active components such as carotenoid content, polysaccharides, sterols, vitamins and protein. Since pumpkin has perishable characteristics, pumpkin must be preserved to increase the shelf life. The present study describe the possibility of producing spraydried pumpkin extract to increase the shelf life. Since pumpkin have high viscosity, it tend to cause deposit in the wall of spray drying chamber. With the help of enzyme liquefaction technique, the viscosity of the pumpkin can be reduced. In this research, pumpkin puree were individually treated with Pectinex Ultra-SP (0-2.5% w/v). Then, concentration Pectinex Ultra SP that produce the best viscosity reduction of pumpkin puree were chosen and treated with Celluclast 1.5 L (0-2.5% w/v). The results showed that 2.5% w/v of both Pectinex and Celluclast 1.5 L produced high viscosity reduction, clarity, total soluble solid and low pH. Then this pumpkin extract are subjected to spray drying condition and physical properties are measured. The spray drying of pumpkin extract with 2.5% w/v Celluclast 1.5 L and 2.5% w/v of Pectinex Ultra SP showed the higher yield of pumpkin powder, while no differences in moisture content, water activity and colour.

A life cycle analysis comparing coal liquefaction techniques: A health-based assessment in China

As an emerging coal chemical industry, explorations on the feasibility and benefits of coal-to-liquid (CTL) have attracted the attention of researchers. However, there is no specialized research discussing occupational health damage in this field, which is our concern. To fill this gap and compare three conventional liquefaction routes from health damage, three demonstration projects in China are discussed. Using life cycle assessment (LCA), technical routes of CTL are divided into several substages at first, then a health-based assessment model is established to estimate and monetize the health burden of various harmful factors, which could help to grasp production stages with greater pollution, and provide reference for stakeholders to select the best technical option with economic indicator. Results show that the “willingness to pay” (WTP) for the three routes, i.e., indirect liquefaction (ICL), direct liquefaction (DCL), and coal-oil coprocessing (COCP), was CNY 1.27E+11, 4.76E+10, and 7.29E+09, respectively. Severe health damage in this industry is mainly due to toxic and harmful gases, namely, SO2 and NO2, with the percentage of 97%, and they are mostly produced during coal mining and processing. Finally, some practical suggestions are proposed aiming to attract the attraction of enterprises and governments for further implementation in CTL industry.

Bio-oil production by hydrothermal liquefaction of Rhodococcus opacus biomass utilizing refinery wastewater: Biomass valorization and process optimization

In this research, a pure culture of Rhodococcus opacus strain PD630 was used to treat wastewater generated from a refinery and the lipid rich bacterial biomass obtained was converted to bio-oil. A very high removal (70 ± 5%) of organics present in the wastewater was achieved at pH 7 within 96 h along with lipid accumulation of 50 ± 4% w ∕ w by the bacteria. The lipid containing biomass procured by using the wastewater as the sole substrate was converted into bio-oil by hydrothermal liquefaction (HTL) technique. Different operational parameters viz . temperature, time and biomass/water ratio were optimized employing Response Surface Methodology (RSM) to achieve maximum bio-oil yield. The optimum conditions for maximum bio-oil yield (25.53%) were found to be 215 °C, 125 min and 0.25 biomass/water ratio; the bio-oil had a high heating value (HHV) of 20.73MJ/Kg, and it also contained a very low amount of water soluble products in it. GC–MS analysis of the obtained bio-oil product revealed the presence of a variety of compounds, mainly aldehydes, ketones and fatty acids, whereas the water soluble product contained mainly alcohols and phenolic compounds. Further analysis of the aqueous phase obtained as a byproduct concluded its potential for reuse owing to the presence of nutritional compounds. FTIR spectra of bio-oil revealed the presence of C–H bonds due to alkanes as the predominant functional group present in the product. FAME analysis results and other properties of the transesterified bio-oil matched well with the ASTM standard thus indicating its potential for bio-fuel application. This experimental study thus demonstrated that the lipid rich R. opacus biomass grown on cheaply available refinery wastewater is highly suited for potential bio-oil production. • High organic removal from refinery wastewater was achieved by R. opacus . • The lipid-rich bacterial biomass was converted to bio-oil. • Optimization of process parameters increased the bio-oil yield up to 25%. • The bio-oil showed excellent potential as a bio-fuel. • Water-soluble by-product of bio-oil production showed reuse potential.

Assessment of soybean protein-based adhesive formulations, prepared by different liquefaction technologies for particleboard applications

The development of a feasible and effective method to liquefy soybean protein with the potential to prepare particleboard for wood furniture remains challenging. In this work, different novel liquefaction technologies were proposed to prepare four different soybean protein liquefied products (noted as LSP-Ӏ, LSP-ӀӀ, LSP-ӀӀӀ, LSP-ӀV) that could be used as the matrix of the adhesives to satisfy spraying operation in particleboard industrial production. The effects of different liquefaction techniques on the molecular weight, chemical structure, crystalline degree and physicochemical properties were explored. Moreover, the boiling water-insoluble content, thermal stabilities and bonding properties of soybean protein-based adhesive prepared by LSP and cross-linker epichlorohydrin-modified polyamide (EMPA) were investigated. The results show that the particleboard bond with the “LSP-ӀV + EMPA” adhesive possesses excellent mechanical strength and dimensional stability which meets the industrial requirement of the particleboard according to the GB/T 4897–2015 commercial standard. Moreover, the liquefaction mechanism of the soybean protein solution with high solid content, low viscosity and suitable molecular weight was proposed, as the breaking of the intermolecular interactions by compound modifier effectively unfolded the polypeptide chains, and the polypeptide chains were uniformly and moderately degraded under mild alkaline conditions. Therefore, the “LSP-ӀV + EMPA” adhesive could be uniformly coated on the wood particles by the spraying process, and an effective cross-linking network system was formed during the hot pressing owing to appropriate molecular weight and more active groups of LSP-ӀV. The application prospect of soybean protein-based adhesives would be greatly broadened in the wood composite fields.

Bio-oil synthesis from cassava pulp via hydrothermal liquefaction: Effects of catalysts and operating conditions

The influence of catalysts and operating conditions on the conversion and yield of bio-crude oil from CP via the hydrothermal liquefaction technique (HTL) were studied. HTL is commonly used to convert CP to bio-crude oil (BCO). Three independent factors—reaction temperatures (250–350 °C), reaction times (30–90 min), and CP concentrations (5–20 wt.%)—were investigated. Proximate analysis showed that CP comprises 84.61% volatile matter and 13.59% fixed carbon. The ultimate analysis demonstrated that CP has carbon and oxygen levels of 44.86% and 46.91%, respectively. Thermogravimetric analysis showed that CP begins to decompose at temperatures between 250–350 °C. The results show that KOH is the most suitable catalyst because it provides the highest BCO yield when compared to other catalysts under the same operating conditions. We found that the ideal operating conditions for maximizing BCO performance are 250 °C, pressure of 17.0 MPa, 90 min, 5 wt.%. Under these conditions, Fourier transforms infrared analysis showed that the most abundant chemical bonds found in BCO were CH3-O, CH3-C, and CH3. The findings of the CHNS analysis showed that BCO has an H/C ratio of 2.25, similar to that of petroleum and bio-diesel. Results from a gas chromatograph-mass spectrometer indicate that a fatty acid group is the main component of BCO.

The effects of low-temperature phenomena on rapid phase transition of liquid hydrogen

The simultaneous rise in hydrogen economy and cryogenic liquefaction techniques for long-distance storage and transportation has incentivized the development of technological solutions based on the liquefied hydrogen. However, detailed models accounting for the peculiar phenomena of this cryogenic system in the case of accidental release, namely cryogenic evaporation rate and para-ortho transformation, are necessary before large-scale commercialization. In this light, this work aims to unravel this gap of knowledge on safety aspects involving liquid hydrogen through a numerical approach. More specifically, the top events that arose from the accidental release of liquid hydrogen in the absence of ignition have been modeled. A proper evaporation sub-model suitable for cryogenic conditions has been selected in accordance with the literature. The quantum mechanics approach was adopted to estimate the thermodynamic properties of the hydrogen configurations accurately. These estimations were compared with data from the literature, showing excellent agreement. The effect of para-ortho transformation was evaluated by implementing the obtained database. Besides, different releasing surfaces and materials were tested, either solid (e.g., concrete) or liquid (i.e., water), resulting in hydrogen release rate ranging from 2.00×10−4 – to 13.90 kg/s). The generated over-pressures were calculated for all the investigated cases and critically compared with numerical data obtained in this work and analytical model retrieved from the current literature. These results indicate that neglecting the para-ortho transformation represents a non-conservative hypothesis. Indeed, peaks potentially producing significant structural damages were observed only in cases where this transformation was considered.

Biomass Pyrolysis Liquefaction Technique: State of Research and Development Trends

Biomass as the only renewable carbon sources in nature are considered to be huge amount, environmentally friendly and carbon neutral resources. Exploiting biomass as an energy utilization not only maximizes deal with the agricultural and forestry waste, but also refining high value-added bio-based chemicals products. As one of the important means of bio-refinery conversion processes, biomass pyrolysis liquefaction technique (BPLT) has been popular in producing fuel product since the late 1970s due to its advantages in its short process, strong adaptability, rapid response, high conversion rate and easy commercialization, etc. This paper provides an overview of current research progresses in the BPLT. Summarizes the latest research results of the combined processes for BPLT in feedstock pretreatment, pyrolysis liquefaction process and bio-oil upgrading. In the section of feedstock pretreatment, three methods of microwave drying, baking and pickling are introduced. In the section of pyrolysis process, two new processes of catalytic pyrolysis and mixed pyrolysis are discussed. The final part of the paper deals with recent technologies from five aspects in the bio-oil upgrading: catalytic hydrogenation, catalytic cracking, catalytic esterification, emulsified fuel and separation and purification. Afterward, the paper analyzes the industrialization development trends of BPLT. The paper suggests that make the production and upgrading of pyrolysis oil to hydrocarbon fuels is an economically attractive path. By critically evaluating their potential and challenges, we finally conclude, with the continuous maturity of various technical links such as feed prep, fast pyrolysis and upgrading, BPLT is expected to form a relatively complete technology industrial chain within 5 to 8 years, and gradually realized the industrialization in the true sense.

Thermal conversion of polystyrene plastic waste to liquid fuel via ethanolysis

Since decades, one of the major troublesome environmental issue to the society is Polystyrene waste. Thermal conversion method can be used to transform the plastic waste into useful energy source. In this study, liquefaction technique using ethanol as a solvent was used to produce liquid fuel from polystyrene. The experiments were performed at different temperatures (290–370 °C), ethanol to polystyrene ratios (0.25:1–4:1) and reaction times (15–75 min) in an autoclave batch reactor. After characterization, quantitative and qualitative evaluation of liquid products; results showed that at temperature of 350 °C, ethanol to polystyrene ratio of 0.5:1 and reaction time of 60 min, highest liquid yield of 84.7 wt% was achieved. The viscosity, density, pH, calorific value and flash point of the oil product at this condition was 0.36 cP, 0.88 g/mL, 6.86, 40.91 MJ/kg and 55 °C respectively. Through GC–MS analysis, it was found that the oil product was mostly composed of aromatics, alkenes and alkyls; which made the liquid oil suitable to be used as fuel. In addition, comparative study was conducted by replacing ethanol with water as solvent under same conditions. Based on results, study proved ethanol to be better solvent than water which is commonly used in liquefaction process. Lastly, the liquid fuel produced is suitable to be used as alternative energy source for conventional fossil fuels.

The Optimization of Plasma Catalytic Liquefaction Technique for the Conversion of Sawdust Into Value-Added Chemicals

Non-thermal plasma is an alternative technology of exploiting biomass for efficient production of value added energy carriers. In this study, plasma catalytic liquefaction (PCL) system is successfully developed to achieve rapid and efficient liquefaction of sawdust in the presence of co-solvent polyethylene glycol 200 (PEG 200) and glycerin as well as the acid catalyst H 2 SO 4 . The influences of different operating factors such as the catalyst concentration, reaction time, molar ratio of PEG 200 and glycerin and the power supply are investigated in terms of the liquefaction yield and solution temperature, while the roles of the applied voltage and the duty cycle of power supply in the PCL process are discussed in detail. Experimental results show that the sawdust could be completely liquefied into crude bio-oil with a high heating value (HHV) of 19.18 MJ/kg in the mixture containing sawdust and solvent in a ratio of 1/7, and 1 wt.% catalyst H 2 SO 4 . Increasing the applied voltage and duty cycle are more efficient giving higher yield of liquid products. Based on the analysis of the processing conditions, suggested that the enhanced performance of the PCL process is linked to the superiority of heating that induced by electric field and the presence of quantities reactive species during the plasma discharge. The physiochemical characteristics of the biomass sample and the liquefied products are interpreted by using elemental analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy (FTIR) and the identities and concentration of the liquid products are determined by gas chromatography-mass spectrometry (GC-MS).

About Making Lignin Great Again-Some Lessons From the Past.

Lignin, the second most abundant biopolymer on the planet, serves land-plants as bonding agent in juvenile cell tissues and as stiffening (modulus-building) agent in mature cell walls. The chemical structure analysis of cell wall lignins from two partially delignified wood species representing between 6 and 65% of total wood lignin has revealed that cell wall-bound lignins are virtually invariable in terms of inter-unit linkages, and resemble the native state. Variability is recognized as the result of isolation procedure. In native state, lignin has a low glass-to-rubber transition temperature and is part of a block copolymer with non-crystalline polysaccharides. This molecular architecture determines all of lignin's properties, foremost of all its failure to undergo interfacial failure by separation from (semi-) crystalline cellulose under a wide range of environmental conditions. This seemingly unexpected compatibility (on the nano-level) between a carbohydrate component and the highly aromatic lignin represents a lesson by nature that human technology is only now beginning to mimic. Since the isolation of lignin from lignocellulosic biomass (i.e., by pulping or biorefining) necessitates significant molecular alteration of lignin, isolated lignins are highly variable in structure and reflect the isolation method. While numerous procedures exist for converting isolated (carbon-rich) lignins into well-defined commodity chemicals by various liquefaction techniques (such as pyrolysis, hydrogenolysis, etc.), the use of lignin in man-made thermosetting and thermoplastic structural materials appears to offer greatest value. The well-recognized variabilities of isolated lignins can in large part be remedied by targeted chemical modification, and by adopting nature's principles of functionalization leading to inter-molecular compatibility. Lignins isolated from large-scale industrial delignification processes operating under invariable isolation conditions produce polymers of virtually invariable character. This makes lignin from pulp mills a potentially valuable biopolymeric resource. The restoration of molecular character resembling that in native plants is illustrated in this review via the demonstrated (and in part commercially-implemented) use of pulp lignins in bio-degradable (or compostable) polymeric materials.