Jude A Onwudili

• BSc, MSc, MBA, PhD
• Reader in Chemical Engineering at Aston University

Climate change is the main driver for sustainable aviation fuels production as a means of decarbonising/defossilising the sector. In this work, several catalysts have been screened to produce aviation fuel (C6-C16) component hydrocarbons from cyclohexanone, a model compound of lignin-derived bio-oils. Using a two-stage two-pot approach, up to 99 %...

The Kolbe‐Schmitt reaction is a classic route for CO2 utilisation through organic synthesis of industrially relevant chemicals. Despite the reaction's long‐standing history, detailed product separation and analysis remain underexplored, which inherently limits an accurate mechanism elucidation. This study introduces a new comprehensive approach for...

Elemental analysis is a fundamental method for determining the carbon, hydrogen, nitrogen, sulphur, and oxygen (CHNSO) contents in organic materials. Automated conventional elemental analysers are commonly used for CHNSO determinations, but they face challenges when analysing volatile organic liquids due to sample losses. This present study explore...

Conversion of CO2 into organic chemicals offers a promising route for advancing the circularity of carbon capture, utilisation, and storage in line with the international 2050 Net Zero agenda. The widely known commercialised chemical fixation of CO2 into organic chemicals is the century-old Kolbe–Schmitt reaction, which carboxylates phenol (via sod...

N-butanol quantitatively converted by Pt/Al2O3-catalysed hydrothermal reforming. High propane yields (≈65 wt%) with selectivity of > 90 % obtained. Propane produced via decarbonylation mechanism and additional reaction routes. Hydrogen produced from water-gas shift and mostly consumed in situ. Catalyst deactivation chiefly via alumina hydrolysi...

Impregnation of metal catalysts into biomass before thermochemical conversion may provide benefits of increased selective reactivity to obtain desirable products. In this work, coconut shells impregnated with increasing loadings of nickel were successfully prepared using a room-temperature impregnation method using a nickel salt solution at 1 and 2...

The combined hydrolysis–deoxygenation method reported here demonstrates the efficiency of hydrogen-free catalytic conversion of lipid-derived multi-fatty acids into renewable drop-in hydrocarbon biofuels.

The energy conversion of nickel-impregnated coconut shells using supercritical water has not yet been explored. The impregnation process was conducted at room temperature and a pH of 5.80 for 72 h. Characterization of the prepared sample confirmed the presence of nickel nanoparticles with an average size of 7.15 nm. The gasification of control and...

Hydroxyaromatic carboxylic acids (HACAs) such as salicylic acids, hydroxynaphthoic acids and their halogenated derivatives are essential feedstocks for the pharmaceutical, dye, fragrance, cosmetic and food industries. Large-scale production of HACAs is currently based on the Kolbe–Schmitt reaction between CO2 and petroleum-based phenolic compounds....

An interdisciplinary approach involving the production and engine testing of a fuel blend containing upgraded bio-oil and fossil-derived solvent has been investigated in this present study. First, a novel 3-stage process of solvent-assisted catalytic upgrading of fast pyrolysis bio-oil was used to obtain a fuel blend with nearly 18 vol% biofuel con...

Conventional biomass gasification involves a complex set of chemical reactions leading to the production of a gas mainly composed on carbon monoxide, hydrogen, carbon dioxide and some methane. Some C2-C5+ hydrocarbon gases are also formed in the gasifier. This review has uniquely focused on the thermochemistries of conventional biomass gasification...

Catalytic methane (CH4) dry reforming (MDR) reaction proceeds with the formation of carbon; hence the effects of the catalyst preparation method on the type of carbon are worth investigating. This study investigated the performance of 20 wt% nickel praseodymium (III) oxide (20 wt% Ni/Pr2O3) catalysts prepared by incipient wetness impregnation (IWI)...

In this present work, the hydrolysis of a sample of rapeseed oil (RSO) and two waste cooking oil (WCO) samples in subcritical water has been carried out in a stirred batch stainless-steel reactor to produce fatty acids. Using RSO as a model triglyceride, the effects of reaction parameters on the yields of fatty acids were investigated to determine...

The production of low-carbon gaseous fuels from biomass has the potential to reduce greenhouse gas emissions and promote energy sustainability, stability and affordability around the world. Glycerol, a large-volume by-product of biodiesel production, is a potential feedstock for the production of low-carbon energy vectors. In this present work, an...

In this present work, thermogravimetric analysis (TGA) was used to study the thermal degradation of a range of lipids and lipid-derived compounds associated with the production of biodiesel. Thereafter, the procedure was used to successfully quantify the compounds of three process streams from a biodiesel plant. Relevant organic chemicals involved...

This work presents techno-economic modelling of four thermochemical technologies that could produce over 22,000 tonnes/year of hydrogen from biomass for >2000 public transport buses. These included fluidised bed (FB) gasification, fast pyrolysis-FB gasification, fast pyrolysis-steam reforming, and steam reforming of biogas from anaerobic digestion...

The displacement and eventual replacement of fossil-derived fuel gases with biomass-derived alternatives can help the energy sector to achieve net zero by 2050. Decarboxylation of butyric acid, which can be obtained from biomass, can produce high yields of propane, a component of liquefied petroleum gases. The use of different gaseous reaction atmo...

Catalytic hydrothermal decarboxylation of biomass-derived butyric acid can produce renewable biopropane as a direct drop-in replacement fuel for liquefied petroleum gases. In this present study, experimental results from a batch reactor have been used to develop a hypothetical continuous process to deliver 20,000 tonnes/year of biopropane, as base-...

Sustainable fuel-range hydrocarbons can be produced via the catalytic decarboxylation of biomass-derived carboxylic acids without the need for hydrogen addition. In this present study, 5 wt% platinum on carbon (Pt/C) has been found to be an effective catalyst for hydrothermally decarboxylating butyric acid in order to produce mainly propane and car...

Trommel fines are a high-ash aggregate waste derived from material recycling facilities (MRFs) and are usually disposed in landfill. Increasing UK landfill tax and environmental concerns, however, calls for a flexible technology that can effectively process and extract valuable energy from trommel fines at high efficiencies. One possible technology...

Nickel iron oxide (NiFe2O4) catalyst was prepared by the combustion reaction method and characterized by XRD, N2 adsorption/desorption, thermogravimetric analysis (TG), and temperature programmed reduction (TPR). The catalyst presented a mixture of oxides, including the NiFe2O4 spinel and specific surface area of 32.4 m2 g−1. The effect of NiFe2O4...

In this study, the effect of moisture contents [2.69 wt% (bone-dry), 5 wt% and 10 wt%] on product yields and process conversion efficiency during fast pyrolysis of a pre-treated trommel fines feedstock was investigated at 500 °C. Experiments were carried out using a 300 g h−1 bubbling fluidised bed rig. Yields of organic liquids ranged from 15.2 to...

In this experimental study, a physically pre-treated trommel fines feedstock, containing 44 wt% non-volatiles (ash and fixed carbon) and 56 wt% volatile matter (dry basis), was subjected to fast pyrolysis to recover energy from its organic load, using a 300 g h⁻¹ bubbling fluidized bed (BFB) fast pyrolysis rig. A physical pre-treatment method (incl...

Ex-situ co-pyrolysis of sugarcane bagasse pith and polyethylene terephthalate (PET) was investigated over zeolite-based catalysts using a tandem micro-reactor at an optimised temperature of 700 °C. A combination of zeolite (HZSM-5) and sodium carbonate/gamma-alumina served as effective catalysts for 18% more oxygen removal than HZSM-5 alone. The co...

Eucalyptus wood chips were reacted under supercritical water conditions to evaluate the effect of a NiFe2O4 catalyst, residence time and temperature parameters. Experiments were performed in a batch reactor at 400 °C , 450 °C and 500 °C using three different amounts of catalyst (0, 1.0, 2.0 g) and three different residence times (30, 45, 60 min). R...

A pre-treated trommel fines feedstock (DPT) with 35.1 wt% ash content and particle size range of 0.5–2 mm was processed through two (100% distilled water and 1% surfactant in distilled water) aqueous agitated washing and sedimentation procedures for ash reduction prior to fast pyrolysis in a bubbling fluidized bed reactor. The washing process led t...

The pyrolysis-catalysis of a simulated mixture of plastics representing the plastic mixture found in municipal solid waste has been carried out to determine the influence of process conditions on the production of upgraded fuel oils and chemicals and gases. The catalysts used were spent zeolite from a fluid catalytic cracker (FCC), Y-zeolite and ZS...

The effect of heating rates ranging from 5 °C min-1to 350 °C min-1on the yields of pyrolysis products of wood and its main pseudo-components (cellulose, hemicellulose and lignin) have been investigated at a temperature of 800 °C in a horizontal fixed bed reactor. Results showed a successive dramatic increase and decrease in gas and liquid yields, r...

In this work, the supercritical water gasification of eucalyptus wood chips has been investigated in relation to reaction temperature and presence of catalyst. Experiments were performed in a batch reactor at 450 ºC and 500 ºC with two different feed concentrations. This work wanted to evaluate mainly the gases were formed during the reactions. The...

Energy from Waste (EfW) technologies such as fluidized bed fast pyrolysis, are beneficial for both energy generation and waste management. Such technologies, however face significant challenges due to the heterogeneous nature, particularly the high ash contents of some municipal solid waste types e.g. trommel fines. A study of the physical/mechanic...

Refuse derived fuel (RDF) was processed using hydrothermal gasification at high temperature to obtain a high energy content fuel gas. Supercritical water gasification of RDF was conducted at a temperature of 500 °C and 29 MPa pressure and also in the presence of a solid RuO2/γ-Al2O3 catalyst. The effect of residence time (0, 30 and 60 min) and diff...

Five samples including a composite refuse derived fuel (RDF) and four combustible components of municipal solid wastes (MSW) have been reacted under supercritical water conditions in a batch reactor. The reactions have been carried out at 450 °C for 60 min reaction time, with or without 20 wt% RuO2/gamma-alumina catalyst. The reactivities of the sa...

Here we report on a potential catalytic process for efficient clean-up of plastic pollution in waters, such as the Great Pacific Garbage Patch (GPGP). Detailed catalytic mechanisms of RuO2 during supercritical water gasification of common polyolefin plastics including low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene...

Here we report on a potential catalytic process for efficient clean-up of plastic pollution in waters, such as the Great Pacific Garbage Patch (CPGP). Detailed catalytic mechanisms of RuO2 during supercritical water gasification of common polyolefin plastics including low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene...

A semi-batch pyrolysis process was used to recover samples carbon fibre and glass fibre from their respective wastes. The mechanical properties of the recovered fibres were tested and compared to those of virgin fibres, showing good retention of the fibre properties. The recovered fibres were then used to prepare new LDPE-composite materials with c...

Catalytic supercritical water gasification of heavy (dewatered) bio-oil has been investigated in a batch reactor in the presence of ruthenium catalysts in the form of RuO2 on γ-Al2O3 support. The reactions were carried out at temperatures of 400°C, 450°C and 500°C and reaction times of up to 60min using 15wt% of bio-oil feed. Increased ruthenium ox...

Disposal of waste printed circuit boards is regarded as a potential major environmental problem due to their heavy metal content. Therefore, recycling waste printed circuit boards represents an opportunity to recover the high value resin chemicals and the high value metals that are present. In this study, the solvo-thermal depolymerisation of waste...

Chars produced from the pyrolysis of different waste materials have been investigated in terms of their use as a catalyst for the catalytic cracking of biomass pyrolysis gases during the two-stage pyrolysis-gasification of biomass. The chars were produced from the pyrolysis of waste tyres, refused derived fuel and biomass in the form of date stones...

The integration of hydrothermal liquefaction (HTL) and hydrothermal gasification (HTG) is an option for enhanced energy recovery and potential biocrude upgrading. The yields and product distribution obtained from the HTL of Chlorella vulgaris have been investigated. High conversion of algae to biocrude as well as near complete gasification of the r...

The influence of reaction conditions on the composition of liquid products during two-stage hydrothermal conversion of alkali lignin has been investigated in a batch reactor. Reactions were carried out in the presence of formic acid (FA) and Pt/Al2O3 catalyst. The two different sets of reaction conditions involved alternative reaction times of 1h a...

Real-world post-consumer mixed plastics and a simulated mixture of plastics were processed in a two-stage pyrolysis-catalysis fixed bed reactor in the presence of a Zeolite HZSM-5 catalyst. In addition, single plastic polyethylene, polypropylene, polystyrene and polyethylene terephthalate were also processed in the two-stage reactor. The product yi...

The high-temperature pyrolysis behaviour of a sample of refuse derived fuel (RDF) as a model of municipal solid waste (MSW) was investigated in a horizontal tubular reactor between 700–900 °C, at varying heating rates, and at an extended vapour residence time. Experiments were designed to evaluate the influence of process conditions on gas yields a...

The interactions of polyvinyl chloride (PVC) and biomass components (hemi-cellulose, cellulose and lignin) during fast pyrolysis were investigated at 800 °C in a fixed bed reactor. The interactions of PVC and biomass components decreased the HCl yield and increased the tar yield significantly. During the co-pyrolysis of PVC with the biomass compone...

The formation of 2-4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800°C. The mass distribution...

The effect of reaction conditions, temperature, heating rate, and reaction atmosphere on the formation of polycyclic aromatic hydrocarbons (PAHs) from lignin was studied in a fixed-bed reactor. When the temperature was increased from 500 to 900 degrees C, most PAHs increased with temperature, except 1-methynaphthalene and 2-methynaphthalene, which...

Alkali lignin was subjected to depolymerization in subcritical water at 265 °C, 6.5 MPa for reaction times between 1–6 h in a batch reactor and in the presence of formic acid (FA) and Pd/C catalyst. The oil products were extracted into diethyl ether and contained >90% of single-ring phenolic compounds. The reaction of lignin in subcritical water al...

A sample of pinewood sawdust was rapidly pre-processed in a torrefaction-type procedure, separately in subcritical water (neutral) and with added Na2CO3 (alkaline compound) and Nb2O5 (solid acid) in a batch reactor. The original sawdust and the three friable solid recovered products from the hydrothermal procedure were characterized in detail. The...

Three environmental samples containing dioxins and furans have been oxidized in the presence of hydrogen peroxide under supercritical water oxidation conditions. The samples consisted of a waste incinerator fly ash, sewage sludge and contaminated industrial soil. The reactor system was a batch, autoclave reactor operated at temperatures between 350...

The influence of process conditions on the yield of syngas and hydrogen from the supercritical water gasification of biomass are reviewed. The yield and composition of the products from the processing of model biomass compounds and different types of biomass are discussed. The influence of the key process conditions of temperature, pressure, reside...

Over 90 % of the world’s current hydrogen production capacity comes from the use of fossil fuels including coal, oil, and natural gas. In recent years, natural gas has become the major source of hydrogen. However, these fossil fuels are finite resources, produce greenhouse gases, and will eventually run out. Biomass presents a proven store of chemi...

The composition of syngas and process water from the supercritical water gasification of macroalgae has been investigated. The potential for using the process water as a source of nutrients for microalgae cultivation was assessed. Saccharina latissima, harvested across the four seasons was gasified in a batch reactor at 500 C and 36 MPa to assess t...

The composition of syngas and process water from the supercritical water gasification of macroalgae has been investigated. The potential for using the process water as a source of nutrients for microalgae cultivation was assessed. Saccharina latissima, harvested across the four seasons was gasified in a batch reactor at 500°C and 36 MPa to assess t...

Carbon reinforced composite plastic (CRCP) waste has been pyrolysed under nitrogen atmosphere in a batch stainless steel autoclave between temperatures of 350 and 500uC and reaction times of up to 60 min. The reaction products were dominated by solid residue (72-77 wt-%), gas (2-4 wt-%) and liquid (22-25 wt-%). The solid residue consisted mainly of...

Thermal processing of biomass in the presence of a catalyst is a promising technology to generate H2-rich gases for fuelling the future. Metal particles loaded on porous supports have been widely used for biomass gasification. However, no detailed research has been designed for describing the catalytic performance of nickel particles located inside...

Gasification technology is an attractive alternative for the thermal treatment of solid wastes, producing a high energy value hydrogen rich syngas. The presence of tar in the produced gas diminishes its quality and potential use in further processes; for this reason the reduction of tar in waste gasification is a major challenge. In this work the p...

A two-stage batch hydrothermal process has been investigated with the aim of enhancing the yields of hydrogen and methane from sawdust. Samples of the sawdust were rapidly treated in subcritical water and with added Na2CO3 (alkaline compound) and Nb2O3 (solid acid) at 280 °C, 8 MPa. Each pre-processing route resulted in a solid recovered product (S...

The potential of hydrogen as a fuel source has been increasing as it involves clean combustion compared with the greenhouse gases emissions from the combustion of fossil fuels; additionally hydrogen can be used as fuel in fuel cells or hydrogen powered turbines. The current hydrogen production processes involve the use of fossil fuels by natural ga...

A series of Ni/SiO catalysts have been prepared and investigated for their suitability for hydrogen production and tar reduction in a two-stage pyrolysis-reforming system, using refuse derived fuel (RDF) as the raw material. Experiments were conducted at a pyrolysis temperature of 600°C, and a reforming temperature of 800°C. The product gases were...

A series of Ni/SiO2 catalysts have been prepared and investigated for their suitability for hydrogen production and tar reduction in a two-stage pyrolysis-reforming system, using refuse derived fuel (RDF) as the raw material. Experiments were conducted at a pyrolysis temperature of 600 °C, and a reforming temperature of 800 °C. The product gases we...

Ruthenium supported on alpha-alumina spheres has been employed as a catalyst for the gasification of glucose and other biomass-related samples in supercritical water at 550 °C, 36 MPa, in a batch Inconel reactor. Most of the reactions were conducted in the presence of alkaline additives particularly sodium hydroxide and calcium oxide (hydroxide). I...

Recovery of carbon fibre and chemical feedstock via catalytic hydrothermal degradation of waste carbon fibre reinforced plastic (CFRP) sample was investigated in a stainless steel batch reactor between 400 and 420 °C and pressures of 20 and 25 MPa, respectively. Sodium hydroxide and potassium hydroxide were used as catalysts/additives. Using superc...

carbon fiber composite was pyrolysed in autoclave reactor under temperature between 350-500 C and for 60 mins. the mechanical properties of regenerated carbon fibers were lower than the virgin ones . the pyrolysis products were 2-4 gas, 20-25 liquid and the rest was solid.

Chlorella vulgaris, Spirulina platensis and Saccharina latissima were processed under supercritical water gasification conditions at 500°C, 36MPa in an Inconel batch reactor for 30min in the presence/absence of NaOH and/or Ni-Al(2)O(3). Hydrogen gas yields were more than two times higher in the presence of NaOH than in its absence and tar yields we...

The gasification of wastes represents a major thermochemical route to produce a high energy value, hydrogen rich syngas from a source which is renewable and CO2-neutral. However, one of the major issues in the gasification process is the production of tar. Tar is a complex mixture of condensable hydrocarbons and causes major process and syngas use...

Two nickel-based catalysts were prepared and investigated in relation to their influence over aromatic compounds contained in tar from the pyrolysis–gasification of refuse derived fuel (RDF), using a two-stage reaction system. The results were compared with those obtained in experiments carried out using a bed of sand, both with steam and without s...

The influence of gaseous ammonia and sulphur dioxide on the formation of 2378-substituted PCDD/F on a reference flyash from a municipal waste incinerator has been investigated using a laboratory scale fixed-bed reactor. The reference flyash samples (BCR-490) was reacted under a simulated flue gas stream at temperatures of 225 and 375°C for 96h. The...

The reactions of different food classes during alkaline subcritical water gasification have been investigated with a view on hydrogen gas production. Experiments were conducted with sub-stoichiometric amounts of H2O2 for partial oxidation. NaOH was added to aid sample decomposition, reduce char/tar formation and to promote water-gas shift reaction....

Hydrothermal treatment involving the oxidation and gasification of sewage sludge and pharmaceutical wastewater samples has been carried out in batch autoclave reactor. The efficiency of the oxidation processes measured in terms of total organic carbon (TOC) and total solids (TS) removal showed that effective sample treatments were achieved at moder...

The seventeen 2378-substituted polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs) congeners have been separated and analyzed in sewage sludge and incinerator flyash samples using a CP-Sil 88 column (50 m × 0.25 mm I.D., 0.25 μm film thickness) operating at a maximum oven temperature of 240°C. The column was used on a Varian 450-GC wit...

The yield of PCDD/F in relation to the presence of oxygenated PAH in model waste incinerator flyash has been investigated in a fixed bed laboratory scale reactor. Experiments were undertaken by thermal treatment of the model flyash at 250 and 350°C under a simulated flue gas stream for 2 h. After reaction, the PCDD/F content of the reacted flyash a...

The gasification of wastes and biomass is regarded as a viable thermal treatment process to produce syngas composed largely of hydrogen, methane, carbon monoxide and carbon dioxide. However, the process of gasification could be improved if the residual tar could be converted to hydrogen and methane gas and the carbon dioxide could be adsorbed via c...

The application of activated carbons has become a commonly used emission control protocol for the removal or adsorption of persistent organic pollutants from the flue gas streams of waste incinerators. In this study, the 2378-substituted PCDD/F removal efficiency of three types of activated carbons derived from the pyrolysis of refuse derived fuel,...

The near-critical water gasification of dairy industry waste in the form of Whey, a product composed of mixtures of carbohydrates (mainly lactose) and amino acids such as glycine and glutamic acid, has been studied. The gasification process involved partial oxidation with hydrogen peroxide in the presence of NaOH. The reactions were studied over th...

Reactions of different carbonaceous materials in alkaline hydrothermal media have been studied in a batch reactor. In general, hydrogen gas production increased in the presence of sodium hydroxide for all samples. Based on experimental evidence, a chemical reaction model was developed for hydrogen gas production from these reactions. Evaluation of...

In this work, the hydrothermal reactions of ‘intermediate’ compounds of hydrothermal biomass decomposition have been investigated in relation to reaction temperature and time. Experiments were carried out in a batch Hastelloy-C reactor from 250 °C and 4 MPa up to 500 °C and 43 MPa. The results indicate that sodium formate decomposes to mainly H2 (u...

Pyrolysis of brominated flame retardant-containing high-impact polystyrene (HIPS-Br) was performed at 430°C in the presence of 0.1 wt% of polyethylene terephthalate (PET) in a Pyrex glass reactor. Two different types of brominated flame retardants (decabromodiphenyl ether and decabromodiphenyl ethane) with or without antimony trioxide (as synergist...

Sub-critical water gasification by partial oxidation of glucose was carried out in the presence of various alkali catalysts; NaOH, KOH, Ca(OH)2, Na2CO3, K2CO3 and NaHCO3. Experiments were carried out in a closed batch reactor under sub-critical water conditions of 330°C temperature and 13.5MPa pressure. Hydrogen gas yield in relation to the alkali...

The production of hydrogen via subcritical water gasification of model food waste compounds, glucose and glutamic acid representing carbohydrate and protein has been studied. The influence of NaOH additive, Ni/Al2O3 and Ni/SiO2 catalysts and combinations of these catalysts in relation to hydrogen production was investigated at a temperature of 330...

The gasification of some selected components of food wastes using H(2)O(2) as the oxidant and in the presence of NaOH has been investigated under subcritical water conditions. Hydrogen production was enhanced when both NaOH and H(2)O(2) were used compared to when either NaOH or H(2)O(2) alone was used or in their absence. Results indicated that the...

The effects of Pt/Al2O3 and Rh/Al2O3 catalysts on the pyrolysis of low-density polyethylene (LDPE) at a temperature of 425 °C and residence time of 1 h was investigated in a batch stainless steel autoclave reactor. Preliminary observations showed that neither catalyst lowered the degradation temperature of LDPE. Generally, the presence of either ca...

A parametric study of alkali-promoted hydrogen gas production from by-products from food-based biomass, such as glucose, molasses and rice bran, under hydrothermal conditions has been carried out. Partial oxidation of the biomass samples was aided by the addition of hydrogen peroxide and experiments were carried out in the presence of sodium hydrox...

A viscous waste derived from a bio-diesel production plant, in the form of crude glycerol, was reacted under subcritical and supercritical water conditions and the product composition determined in relation to process conditions. Preliminary analysis of the original sample showed that the main constituent organic compounds were methanol (20.8 wt.%)...

The compositions of the pyrolysis products of pure low-density polyethylene (LDPE) and polystyrene (PS) and their mixtures have been investigated over a temperature range from 300 to 500 °C. The pyrolysis experiments were carried out in a closed batch reactor under inert nitrogen atmosphere to study the effects of reaction temperature and residence...

The role of sodium hydroxide as a promoter of hydrogen gas production during the hydrothermal gasification of glucose and other biomass samples has been investigated. Experiments were carried out in a batch reactor with glucose and also in the presence of the alkali from 200 °C, 2 MPa to 450 °C, 34 MPa at constant water loading. Without sodium hydr...

Two of the most commonly used brominated plastics in electrical and electronic goods, Br-ABS and Br-HIPS have been degraded in supercritical water up to 450°C and 31MPa in a batch Hastelloy-C reactor. The plastics were reacted both in the absence and presence of alkaline additives, NaOH and Ca(OH)2. The main reaction products were oils with near-ze...

High-impact polystyrene (HIPS) flame retarded with decabromodiphenyl ether (DDE), has been reacted in supercritical water from 380 to 450 degrees C and 21.5 to 31.0 MPa pressure in a batch reactor. Different concentrations of sodium hydroxide additive were used in situ to neutralize the corrosive inorganic bromine species released during the reacti...