Yield Of Solid Residue Research Articles

CO-PROCESSING OF COTTON SOAPSTOCK, COAL DUST AND POLYMER WASTE BY PYROLYSIS METHOD

The work is aimed at solving the problems of rational consumption of secondary raw materials on the basis of carbon-containing waste of industries, saturation of the market with additional products and protection of the environment from the toxic effects of waste. Aim of work: the study of the co-pyrolysis process of gossypol resin (GR) from cotton soapstock of "Shymkentmay" JSC, coal dust (CD) of Kulan deposit and plastics waste (PW) in N2 medium. The methodology of work included the establishment of optimal modes of the process, determination of yield, composition and properties of pyrolysis products. Analysis of pyrolysis products by IR spectroscopy, XRD, chromatomass spectrometry. Study of the component composition of liquid pyrolysis products by the method of extraction separation in Soxhlet apparatus into oils, asphaltenes and resins. Assessment of perspectivity of co- pyrolytic processing of carbon-containing wastes from different industries for industrial development. Results and discussion. The optimum temperature of GR pyrolysis (T=450 ⁰С) was established, at which the yield of liquid product was on average 33.01 wt.%, gas yield – 60.33 wt.%, yield of solid residue – 6.65 wt.%. The co-pyrolysis of GR and CD at 1:1 ratio and T=500 ⁰C in N2 atmosphere was investigated for the first time. A high yield of liquid product – 47.34 wt.%, low gas formation – 2.31 wt.% and a large amount of solid residue – 50.34 wt.% were observed, which is apparently due to the formation of coal semicoke and coke. The process of co- pyrolysis of GR, CD with D=90 μm and PW (PE:HPPP – 1:1) at the ratio of 1:1:1 and temperatures of 500 ⁰С-700 ⁰С in N2 atmosphere was investigated for the first time. It is shown that the main contribution to the formation of liquid products in the given temperature regimes is made by GR and PW. Conclusion. Co-processing of carbon-containing wastes was found to be of interest and practical importance, both in terms of obtaining marketable products and maintaining a safe ecology.

Co-pyrolysis of chrome-tanned leather shavings with wheat straw: Thermal behavior, kinetics and pyrolysis products

The thermal behavior and kinetics of chrome-tanned leather shavings (CLS)/wheat straw (WS) blends at different mass ratios during co-pyrolysis were investigated, and the pyrolysis products were characterized. Model-free isoconversional and master-plots methods were applied to determine kinetic triplet of the pyrolysis/co-pyrolysis of CLS, WS and their blends based on thermogravimetric (TG) analysis. Results showed that the activation energy for CLS pyrolysis was reduced by the addition of WS, and a synergistic promoting effect predominated across the majority of temperature ranges and feedstock compositions during the co-pyrolysis process. TG-Fourier transform infrared spectrometry-Mass spectrometry analysis showed the changes in evolution profiles of H2O, CO, CO2, HNCO and pyrrole during pyrolysis. The pyrolysis solid residues were characterized and results indicated that the addition of WS to CLS can increase solid residue yield and potentially inhibit the formation of hexavalent chromium during pyrolysis. This study helps to foster a promising solution for the valorization and safe disposal of chromium-containing solid wastes from leather industry.

Model-based process intensification of deep eutectic solvent treatment of eucalyptus slabs for lignin extraction and pulp production

This work revealed the reaction characteristics in the delignification process of eucalyptus slabs catalyzed by acidic deep eutectic solvent (benzyltriethylammonium chloride/formic acid) from the perspective of heterogeneous reactions. The limitation of internal diffusion on delignification process cannot be ignored. Afterwards, a kinetic model based on cell wall structure was proposed to describe the relationship between the delignification degree and reaction conditions, and it also hold excellent predictive ability for lignin removal, carbohydrate retention and solid residue yield. Compared with other reported kinetic models, this novel model not only took into account all operational parameters of reaction process, but also can be applied to the entire reaction process without the need for segmentation. Besides, an essential requirement based on the developed model was a 44.40 wt% formic acid concentration and a temperature of 130 °C, when the purpose of DES treatment was pulping. Generally, this work could provide guidance on process adjustments and product quality control during the DES processing.

Enhancement of light hydrocarbon production from polypropylene waste by HZSM-11-catalyzed pyrolysis

Herein, a mixture of real polypropylene (PP) waste was pyrolyzed with a HZSM-11 catalyst as a potential method to recover light hydrocarbons (C ≤ 12), the potential feedstock for value-added chemicals and fuels, from polyolefin plastic waste. Using the HZSM-11 in the PP waste mixture pyrolysis noticeably improved the yield of gas pyrolysate and oil in compensation for the yield of wax (i.e. hydrocarbons of C > 20) and solid residue particularly at a higher temperature. In addition, the selectivity of C3–C12 in the PP-waste mixture-derived pyrolysate was markedly increased by the HZSM-11. The highest yield of light hydrocarbons was ≈40 wt% (per mass of the feedstock) achieved at 700 °C with the HZSM-11 catalyst. Despite 7.9 wt% coke deposition on the HZSM-11 after its use in the pyrolysis of the PP waste mixture, the catalyst could be reusable for at least three times after regeneration. The experimental results demonstrate that HZSM-11 has the potential for being a promising catalyst to valorize polyolefin waste into value-added chemicals.

Optimization of Pyrolysis Process Parameters for Fuel Oil Production from the Thermal Recycling of Waste Polypropylene Grocery Bags Using the Box–Behnken Design

The impact of dumping plastic waste is realized in different ecosystems of the planet. Several methods have been adopted to dispose of these wastes for energy recovery. This study, for the first time, proposed the Box–Behnken design technique to optimize the pyrolysis process parameters for fuel oil production from waste polypropylene (PP) grocery bags using a semibatch-type pyrolytic reactor. The semibatch-type pyrolytic reactor was developed and employed to produce fuel oil from waste PP grocery bags. The effect of different process parameters on fuel oil production was comprehensively analyzed using the response surface methodology (RSM) with the conjunction of the Box–Behnken design (BBD). The BBD facilitates the prediction of the response variables with respect to changes in the input variables by developing a response model. The BBD was used to optimize the process parameters, such as the reaction temperature (400–550 °C), nitrogen flow rate (5–20 mL min−1), and substrate feed rate (0.25–1.5 kg h−1), and their effect on the responses were observed. The optimum response yields of the fuel oil (89.34 %), solid residue (2.74%), and gas yield (7.92%) were obtained with an optimized temperature (481 °C), a nitrogen flow rate (13 mL min−1), and a feed rate (0.61 kg h−1). The quadratic model obtained for the fuel oil response denotes the greater R2 value (0.99). The specific gravity and calorific value of the fuel oil were found to be 0.787 and 45.42 MJ kg−1, respectively. The fuel oil had higher research octane number (RON) (100.0 min) and motor octane number (MON) (85.1 min) values. These characteristics of the fuel oil were matched with conventional petroleum fuels. Further, Fourier transform infrared spectroscopy (FT-IR) and gas chromatography–mass spectroscopy (GC-MS) were used to analyze the fuel oil, and the results revealed that the fuel oil was enriched with different hydrocarbons, namely, alkane (paraffins) and alkene (olefins), in the carbon range of C4–C20. These results, and also the fractional distillation of the fuel oil, show the presence of petroleum-range hydrocarbons in the waste PP fuel oil.

Effect of ternary deep eutectic solvents on delignification of stone pine cone

Due to their cost-effectiveness and environmentally friendly nature, deep eutectic solvents (DESs) hold great potential for applications in biomass conversion and the production of green chemicals. In this study, the delignification of the stone pine (Pinus pinea L.) cone was performed using seven different ternary deep eutectic solvents (TDESs). TDES treatments of stone pine cone samples were carried out in a microwave for 30 min. at 150 °C. The two-based components of TDESs were choline chloride (ChCl - 1 mol) and lactic acid (LA - 9 mol). The formic acid (FA – 2 mol), boric acid (BA – 1 mol), acetic acid (AA – 2 mol), sorbitol (S – 1 mol), triethylene glycol (TEG – 2 mol), ethylene glycol (EG – 2 mol), and glycerol (G – 2 mol) were used as third component of TDES. ChCl:LA:BA gave the lowest solid residue yield (57.90%) and highest lignin purity (86.89%). Klason lignin content of control was 35.08%. The lowest lignin content (19.42%) and highest delignification (68.89%) were obtained with ChCl:LA:FA treatment. The lowest and the highest L* values were obtained from ChCl:LA:BA and ChCl:LA:EG treatments with 21.76 and 37.36, respectively. This results showed that the third component of TDES affects the delignification efficiency of stone pine cone.

Machine Learning Model Insights into Base-Catalyzed Hydrothermal Lignin Depolymerization.

Lignin, an abundant component of plant matter, can be depolymerized into renewable aromatic chemicals and biofuels but remains underutilized. Homogeneously catalyzed depolymerization in water has gained attention due to its economic feasibility and performance but suffers from inconsistently reported yields of bio-oil and solid residues. In this study, machine learning methods were used to develop predictive models for bio-oil and solid residue yields by using a few reaction variables and were subsequently validated by doing experimental work and comparing the predictions to the results. The models achieved a coefficient of determination (R2) score of 0.83 and 0.76, respectively, for bio-oil yield and solid residue. Variable importance for each model was calculated by two different methodologies and was tied to existing studies to explain the model predictive behavior. Based on the outcome of the study, the creation of concrete guidelines for reporting in lignin depolymerization studies was recommended. Shapley additive explanation value analysis reveals that temperature and reaction time are generally the strongest predictors of experimental outcomes compared to the rest.

Low temperature pyrolysis of polylactic acid (PLA) and its products

The fact that polylactic acid (PLA) is not biodegradable makes it necessary to find the methods of effective treatment of its waste. A significant method of processing waste PLA can be slow low-temperature pyrolysis, providing mostly oil and energy gas. The PLA pyrolysis provides almost 50 wt.% oil and 21–23 wt.% energy gas with a high carbon monoxide content above 90 vol.% at temperatures up to 420 °C. The temperatures above 420 °C do not give acceptable yields of oil anymore, and at the same time there are higher losses due to the release of low boiling aldehydes and ketones. The obtained oil and gas showed an acceptable calorific value as a basis for their use as substitute fuels. Due to its composition, oil can also be considered as a source of valuable chemicals (tetrahydrofuran, paraldehyde, cyclopentanone and ether) and gas as a source of carbon monoxide for industrial applications and, more recently, for biomedical use. Even plastic waste mixtures with a high proportion of PLA in a 1:1 ratio can be efficiently processed by slow low-temperature pyrolysis. The pyrolyzed mixture showed very similar yields of solid carbonaceous residue and oil (38 wt.% and 35 wt.%). The composition of the solid phase was only minimally different from the low-temperature pyrolysis of PLA. Although the ratio of PLA:LPO components was 1:1, the CO content decreased by ca. 20 vol.% at the expense of CO2 and lighter C2-C5.

Catalytic hydrothermal liquefaction of orange peels into biocrude: An optimization approach by central composite design

Global instability, persistent increase in pump-price, inflation and depletion of fossil fuel resources amidst the continuous discharge of greenhouse gases from fossil fuels combustion call for urgent attention. The application of novel catalyst towards an improved biocrude production and enhanced biomass conversion are required for effective performance of hydrothermal liquefaction of biomass feedstocks. In the present study, iron supported carbon nanospheres (Fe/CNSs) catalyst has been developed using wet impregnation approach and explored for its catalytic potency in improving yield of biocrude using an optimization approach; central composite design. Hydrothermal liquefaction (HTL) was adopted as a process route where the catalyst dosage (3–6 wt%) and the reaction temperature (330–430 °C) were optimized on the constant weight of orange feedstock (10 g), reaction time of (15 mins) and solvents’ ratio of 3:1 (acetone to ethanol). The performance of the catalyst was found to be aided with the even dispersion of the Fe on the surfaces of the CNSs support and improved surface area. The effects of reaction temperature were observed to be more progressive on biocrude yield formation over the catalyst loading. The optimum biocrude yield, solid residue, biomass conversion and gas yield were obtained to be 71.09 wt%, 28.18 wt%, 71.82 wt% and 40.14 mL/g at 430 °C and 3 wt% catalyst loading. The obtained analysis of variance suggests a good correlation between the experimental and predicted data in all responses. The selectivity of Fe/CNSs catalyst to high yield of phenolics and aromatic compounds in the biocrude suggest that, the biocrude can be further be upgraded into transportation fuel through hydrodeoxygenation process. The findings have further suggested the viability of the developed Fe/CNSs as an effective catalyst for improved HTL products in a batch reactor.

Hydrothermal Liquefaction of Pinewood Sawdust: Influence of Reaction Atmosphere

Hydrothermal liquefaction (HTL) is a thermochemical process for production of biocrude oils, commonly from wet biomass under inert atmosphere (N2). Influence of reaction atmosphere on HTL of pinewood sawdust was investigated in this work, at 300 °C for 60 min with the presence of KOH or H2SO4 catalyst under N2, H2, and O2 atmosphere, respectively. Very interestingly, the reaction atmosphere showed significant influence on both products distribution and properties of the biocrude oils. Generally, H2 atmosphere enhanced biomass degradation in the presence of either KOH or H2SO4 catalyst, producing the highest biocrude oil yield, lowest solid residue yield, and the best oil quality in terms of total acid number (TAN), viscosity and average molecular weights (Mn, Mw). Whereas the HTL in O2 atmosphere showed the poorest performance in terms of yields and properties of biocrude oils. The highest quality of biocrude oil was produced using KOH catalyst in H2 atmosphere with the maximum biocrude yield (approx. 34 wt.%) and the highest energy recovery (ER) in biocrude (ER = 73.14%). The measured properties of the oil are as follows: TAN = 40.2 mg KOH/g, viscosity = 51.2 cp, Mn = 470 g/mol, Mw = 767 g/mol. In addition, the biocrude oils produced in H2 atmosphere contain more light oil (naphtha) fraction (23.9 wt.% with KOH and 16.5 wt.% with H2SO4) with lower boiling points, while those generated in O2 atmosphere have more carboxylic acid compounds.

Machine Learning Assisted Chemical Process Parameter Mapping on Lignin Hydrogenolysis

Lignin depolymerization has been studied for decades to produce carbon-neutral chemicals/biofuels and biopolymers. Among different chemical reaction pathways, catalytic hydrogenolysis favors reactions under relatively mild conditions, while its yield of bio-oil and high-value aromatic products is relatively high. In this study, the influence of reaction parameters on lignin hydrogenolysis are discussed by chemical process parameter mapping and modeled using three different machine learning algorithms based upon literature experimental data. The best R2 scores for solid residue and aromatic yield were 0.92 and 0.88 for xgboost, respectively. The parameter importance was examined, and it was observed that lignin-to-solvent ratio and average pore size have a larger impact on lignin hydrogenolysis results. Finally, the optimal conditions of lignin hydrogenolysis were predicted by chemical process parameter mapping using the best-fit machine learning model, which indicates that further process improvements can potentially generate higher yields in industrial applications.

HYDROGENATION OF ABIES WOOD ETHANOL-LIGNIN WITH HYDROGEN IN ETHANOL MEDIUM IN THE PRESENCE OF NiCuMo/SiO2 CATALYST

In the development of studies on the catalytic conversion of lignin to liquid hydrocarbons, the effect of the bifunctional NiCuMo/SiO2 catalyst on the yield and composition of abies wood ethanol-lignin hydrogenation products in ethanol medium at a temperature of 250 °C was established. According to thermogravimetric analysis data the main thermal decomposition of abies wood ethanol-lignin occurs in the range from 260 to 600 °C with the maximum rate of degradation (3.9%/min) at 398.3 °C. The catalyst increases the yield of liquid products from 75.0 to 88.0 wt%, and reduces the yield of solid residue from 14.0 to 0.6 wt%. The total yield of phenolic compounds of non-catalytic hydrogenation does not exceed 4.5 wt%. The bifunctional nickel-containing catalyst increases by two times (up to 9.2 wt.%) the yield of liquid phenolic products, among which dimers and 4-propyl guaiacol predominate. The molecular weight distribution of the liquid products of the catalytic hydrogenation of abies ethanol-lignin shifts to the low molecular weight region due to the increase in the content of dimeric and monomeric phenolic compounds in liquid products. The obtained methoxyphenols can be used as components of epoxy resins, polycarbonates, fuel additives, and in other areas.

Co-pyrolysis of paper mill sludge and textile dyeing sludge with high calorific value solid waste: Pyrolysis kinetics, products distribution, and pollutants transformation

Paper mill sludge (PMS) and printing and textile dyeing sludge (TDS) are two typical industrial sludge with high calcium content, high ash content and low calorific value. To attain effective removal of industrial solid waste, in this study, PMS and TDS are first pyrolyzed independently to study their thermochemical behavior. Results show that 600 °C is the optimal pyrolysis temperature for both PMS and TDS from the perspective of organics degradation. However, the yield and quality of pyrolysis oil and gas are still at low level due to the characteristics of high ash content and low organic content, which is not suitable for fuel recovery. Two kinds of organic solid wastes with high calorific value, duckweed (DW) and waste tire (WT), are co-pyrolyzed with PMS and TDS, which can effectively reduce activation energy and increase the yield of liquid and gas products. The most prominent is P1D1 pyrolysis gas, the production of CH4 and C2-C3 increased from 10.80 L/kg and 3.89 L/kg to 20.16 L/kg and 15.58 L/kg respectively, and the high calorific value also increased to 230.93 kJ/kg. The quality of pyrolysis liquid has been improved significantly as the declined N and O-heteroatom content (especially for P1D1 and T1W1) due to the inhibition effect of co-pyrolysis on the N/O migration into pyrolytic liquid. The solid residue from the co-pyrolysis of PMS and DW contains rich N-functional groups and can promote the conversion of pyridinic-N and pyrrolic-N to quaternary-N. Compared with independent pyrolysis, co-pyrolysis can promote the degradation of harmful organic matter in sludge. The addition of DW and WT co-pyrolysis reduced the solid residue yield of PMS by 19.9 wt% and 14.9 wt% (13.4 wt% and 10.5 wt% for TDS). This work provides inspiration for further understanding the safe disposal of PMS and TDS by pyrolysis.

Production of bio‐polyurethane (BPU) foams from greenhouse/agricultural wastes, and their biodegradability

AbstractThe exploration of effective utilization of greenhouse wastes is challenging. This paper demonstrates a hydrothermal treatment approach involving the co‐liquefaction of greenhouse wastes with agricultural residue in a mixed solvent of water and ethanol in the presence of a base catalyst, to convert greenhouse wastes and corn stalk into bio‐oil/bio‐polyol at a very high yield of 57.2%, accompanied by a very low yield of solid residue. This bio‐oil (hydroxyl number: 305 mg KOH/g) was successfully used as bio‐polyol to substitute up to 50% petroleum‐based polyol for the preparation of bio‐polyurethane (BPU) foams. The biodegradability of the BPU foams was also studied by incubation with Dyella sp. for a period of 8 weeks. The weight loss, Fourier‐transform infrared (FTIR) spectra, thermogravimetric analysis (TGA) results, and scanning electron microscopy (SEM) images of foam samples were collected and analyzed. The BPU foams exhibited much better biodegradability than the petroleum‐based polyurethane (PU) foam. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd

Study on Selective Preparation of Phenolic Products from Lignin over Ru–Ni Bimetallic Catalysts Supported on Modified HY Zeolite

The catalytic depolymerization of organic solvent lignin with the prepared catalyst 2.5Ru–10Ni/Al-HY was investigated in a high-pressure reactor. Effects of different catalysts, temperature, time, recyclability for catalyst, and solvents on the catalytic performance were explored. The optimal reaction conditions were reaction time 5 h and temperature 280 °C in ethanol solvent. As a result, the highest yield of phenolic monomers was 20.2 wt %, the yield of solid residue was only 4.8 wt %, and the gas products were CH4, C2H6, and CO mainly. With the increase of cycle times, the catalyst had no obvious deactivation, indicating a unique cycle stability. Through NMR characterization of lignin and depolymerization products, it was found that the signals of the original structures (A, B, and C) in lignin disappeared after reaction. According to the analysis of the reaction path, the depolymerization of lignin mainly included the depolymerization of lignin into reaction intermediates and the formation of phenolic compounds by breaking chemical bonds. This research showed a method for preparing phenolic products by the molecular sieve catalyzed depolymerization of lignin.

Flow-through strategy to fractionate lignin from eucalyptus with formic acid/hydrochloric solution under mild conditions

Formic acid is an attractive solvent for the fractionation of lignocellulose for the production of biomaterials and chemicals, while the operation conducted in a batch manner is not conducive to mass transfer in separation process. In this research, eucalyptus was fractionated with formic acid/hydrochloric solution in a flow-through reactor at 95 °C, and the structural characteristics and the composition of fractionated lignin in different stages were investigated. Results showed that the fractionation efficiency was notably improved with a flow-through reactor, as evidenced by the low solid residue yield of 49.5% and the lignin removal rate of 79.4% as compared to the batch manner. During the fractionation process, the dissolution rate of lignin decreased gradually, and the obtained lignin samples showed low molecular weight (<3000), good uniformity (<2), and high thermal stability. The structure analysis showed that β-O-4, β-β, and β-5 linkages in lignin were degraded to varying degrees with increased time, and the degradation of G units was more severe than S ones.

Numerical simulation of fluidized bed pyrolysis under a simplified comprehensive multistep kinetic mechanism: Effects of particle size and fluidization velocity

This study simplified a comprehensive multistep kinetic mechanism of fast biomass pyrolysis in a fluidized bed reactor (involving dense and dilute flows). A wide range of bioparticle sizes (0.2–2.0 mm) was investigated under four fluidization velocities (0.1–0.65 m/s). A multifluid model integrated with heterogeneous chemical reactions was developed to simulate fast biomass pyrolysis in a two-dimensional computational domain. The simplified multistep comprehensive reaction corresponded well to the product yield and composition data previously obtained through experimental pyrolysis. Most of the pyrolysis reactions occurred in the dense region and suddenly reduced the reaction rate in the freeboard. The relatively small size of the bioparticles facilitated their removal from the reactor, improved mixing performance, and resulted in a larger gas–bioparticle heat transfer coefficient and a faster reaction rate. However, particles that were excessively small (0.2 mm) shortened the bioparticle residence time substantially; this resulted in a considerable increase in the solid residue yield, the consumption of slightly more heat for pyrolysis, and further reduction in pyrolysis efficiency. Higher fluidization velocity led to shorter bioparticle residence time and improved the mixing performance of the solids, with a weak effect on the gas–bioparticle heat transfer coefficient. With a broader distribution region, this high velocity reduced the reaction rate slightly and increased the specific heat for pyrolysis substantially (from ∼879 kJ/kg to ∼4043 kJ/kg), thus reducing the pyrolysis efficiency (from 92.8% to 94.3% to 74.4%–76.9%).

Thermochemical conversion of mulching film waste via pyrolysis with the addition of cattle excreta

Herein, the pyrolysis of mulching film waste (an agricultural plastic waste) with cattle excreta (livestock organic waste) was investigated as the efficient simultaneous treatment of plastic and organic wastes. For pyrolysis of mulching film waste or cattle excreta, an increase in temperature increased the yield of non-condensables and decreased the yield of condensables or solid residue. The mulching film waste-derived pyrolytic product was composed largely of a wide range of hydrocarbons (C1–C44), while the cattle excreta-derived pyrolytic product was composed of a variety of chemical groups such as oxygenates, polycyclic aromatic compounds, N-, S-, and B-containing compounds, and halogenated compounds. Pyrolysis temperature had no significant effect on the selectivity toward each chemical groups found in the condensables derived from either the mulching film waste or cattle excreta. The addition of the cattle excreta to the pyrolysis of the mulching film waste increased the yield of non-condensables and enhanced selectivity toward H2 between 500 °C and 900 °C, compared to the pyrolysis of the mulching film waste only. The pyrolysis of the mulching film waste/cattle excreta mixture led to the condensables with lower contents of N, S, B, and halogens than the pyrolysis of a single feedstock. This study is to propose thermochemical conversion pathway of agricultural plastic waste along with livestock organic waste as an effective strategy for waste-to-resources.

Single-Use Disposable Waste Upcycling via Thermochemical Conversion Pathway.

Herein, the pyrolysis of two types of single-use disposable waste (single-use food containers and corrugated fiberboard) was investigated as an approach to cleanly dispose of municipal solid waste, including plastic waste. For the pyrolysis of single-use food containers or corrugated fiberboard, an increase in temperature tended to increase the yield of pyrolytic gas (i.e., non-condensable gases) and decrease the yield of pyrolytic liquid (i.e., a mixture of condensable compounds) and solid residue. The single-use food container-derived pyrolytic product was largely composed of hydrocarbons with a wide range of carbon numbers from C1 to C32, while the corrugated fiberboard-derived pyrolytic product was composed of a variety of chemical groups such as phenolic compounds, polycyclic aromatic compounds, and oxygenates involving alcohols, acids, aldehydes, ketones, acetates, and esters. Changes in the pyrolysis temperature from 500 °C to 900 °C had no significant effect on the selectivity toward each chemical group found in the pyrolytic liquid derived from either the single-use food containers or corrugated fiberboard. The co-pyrolysis of the single-use food containers and corrugated fiberboard led to 6 times higher hydrogen (H2) selectivity than the pyrolysis of the single-use food containers only. Furthermore, the co-pyrolysis did not form phenolic compounds or polycyclic aromatic compounds that are hazardous environmental pollutants (0% selectivity), indicating that the co-pyrolysis process is an eco-friendly method to treat single-use disposable waste.

Hydrothermal liquefaction of olive oil residues

Hydrothermal liquefaction (HTL) of olive oil residues was conducted at various temperatures (250, 270, 300 and 330 °C) and residence times (5, 15, 30, and 60 min). The effect of metal chlorides (AlCl3 and SnCl2) on product yields and compositions was investigated under optimum conditions (300 °C for 15 min). Bio-oil and solid residue yields from the non-catalytic run were 30.8 and 31.8 wt%, respectively. Use of metal chlorides led to decreased bio-oil yields and increased solid residue yields. Experiments were also carried out using methanol, with and without catalysts, and under identical conditions. The bio-oil yield from the non-catalytic supercritical methanol liquefaction (SCMEL) was 33.5 wt%, increasing to 40.3 wt% with AlCl3, however, SnCl2 had almost no effect on bio-oil yield. The heating values of bio-oils from HTL runs were higher than those of corresponding SCMEL runs, and the highest heating value of bio-oil (34 MJ/kg) was obtained with AlCl3. Phenols and ketones were major bio-oil constituents in the HTL runs, whereas esters were the most abundant compounds in bio-oils from SCMEL runs.