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In this work, pyrolysis technology was used to convert biomass and waste to energy. Polystyrene wastes (Thermocol) were co-pyrolyzed with non-edible seed (such as Karanja and Niger) to enhance the quality of pyrolytic oil. The aim was to enhance the calorific value, cold flow properties and to reduce the viscosity of co-pyrolytic oil. For that purpose, waste polystyrene was mixed with the seeds in different proportions. The yield and quality of co-pyrolytic oil was compared with the thermal pyrolytic oil of these seeds as reported in literature. This study confirmed that co-pyrolysis of waste polystyrene and seed not only enhanced the conversion of seed to product but also significantly affected the co-pyrolytic oil fuel properties. Viscosity of the co-pyrolytic oil was reduced with increasing the ratio of seed to waste polystyrene. Similarly, higher calorific value co-pyrolytic oil was obtained at 2:1 ratio compared to other ratios. The comparison between the seed thermal pyrolytic oil and co-pyrolytic oil confirmed that co-pyrolysis of waste polystyrene and biomass altered the composition of pyrolytic oil which had a positive influence on the quality of co-pyrolytic oil. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of Niger seed was investigated with and without the presence of catalyst. [•] The yield of oil during thermal and catalytic pyrolysis was more or less similar. [•] Kaolin at 8:1 ratio was more suitable to enhance calorific value of pyrolytic oil. [•] CaO at 8:1 ratio was able to reduce the viscosity of pyrolytic oil. [•] Pyrolytic oil contains both saturated and unsaturated hydrocarbon compounds. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thermal and catalytic pyrolysis of one non-edible oil seed Mahua was carried out. [•] 525°C was the optimum temperature to produce maximum pyrolytic liquid. [•] Yield of pyrolytic oil was higher for catalytic pyrolysis than thermal pyrolysis. [•] CaO as catalyst increased the calorific value and decreased the viscosity. [•] The catalytic pyrolytic oil has closer fuel properties with that of diesel. [ABSTRACT FROM AUTHOR]

Highlights: [•] 55.17%, Weight basis yield was reported for thermal pyrolysis of Karanja seed. [•] CaO, Al2O3 and Kaolin were used as catalysts for catalytic pyrolysis. [•] The yield of pyrolytic oil was high at 8:1 feed to catalyst ratio. [•] Al2O3 and Kaolin proved to be better than CaO in terms of pyrolytic liquid yield. [•] All the catalysts were capable to enhance the fuel quality of pyrolytic oil. [ABSTRACT FROM AUTHOR]

• Manilkara zapota seed is a waste biological resource available in India. • This seed was pyrolyzed over ZSM-5 in a semi-batch reactor. • Yield of biochar decreased with increase in temperature from 400 to 600 °C. • Introduction of catalysts reduced oxygenated compounds and increased the hydrocarbons. • Catalyst also increased the energy content of pyrolytic oil. The present study addressed the thermal and catalytic pyrolysis of Manilkara zapota seeds (CK) using a semi-batch reactor to understand the effect of process parameters and ZSM-5 on the yield and properties of pyrolytic end products. The physicochemical results endorsed the inherent competence of CK for production of renewable fuels and allied chemicals. Pyrolysis was conducted at varying biomass to catalysts ratios (B/C) (3:1, 6:1, 8:1 and 10:1, respectively) at optimized process conditions. The pyrolysis results confirmed that thermal pyrolysis produced a higher yield of pyrolytic liquid (45.22 wt%) than catalytic pyrolysis (37.98 wt%) at 8:1 B/C ratio. However, the introduction of catalyst improved the properties of catalytic pyrolytic oil vis-à-vis thermal pyrolytic oil by dampening its oxygenated products and viscosity, while increasing the gross heating value (40.38 MJ kg−1). The FTIR study of thermal and catalytic pyrolytic oil confirmed the presence of water, acid, alkane, aromatic, and phenol while GC–MS results demonstrated the use of the catalyst at optimised conditions predominantly reduced the oxygenated products and acids while substantially increased the hydrocarbons. Furthermore, the characterisation of CK biochar confirmed its potential towards utilisation in various industrial and domestic applications. [ABSTRACT FROM AUTHOR]

• Dahlia flower is an abundant and low-cost biological resource. • XRF analysis confirmed the presence of useful compounds. • Kinetic and thermodynamic parameters were calculated to understand its pyrolysis behavior. • Pyrolysis experiments were performed in Py-GC–MS at multiple temperatures. • Py-GC–MS analysis confirmed formation of higher amount of hydrocarbons at 550 °C. To explore the bioenergy potential, kinetic and pyrolysis behavior of waste dahlia flowers (DF), model-free methods and Py-GC–MS were used. Kinetic characteristics of DF biomass were estimated by adopting four model-free methods, Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman, and Distributed Activation Energy (DAEM). Further, functional groups, the presence of mineral matter in DF biomass, and mineral compounds present in the inorganic residue were analyzed using FTIR, EDX, and XRF. Physicochemical analysis results confirmed its bioenergy potential for conversion into renewable fuel and valuable chemicals. The kinetic results of DF biomass showed that activation energy varied with conversion value, and the thermodynamic analysis indicated multiple step pyrolysis. FTIR analysis confirmed the presence of hemicellulose, cellulose, and lignin in biomass. EDX and XRF analysis also revealed the presence of various useful mineral matter, which had a positive effect during pyrolysis. Py-GC–MS results confirmed that at a lower temperature (500 °C), the formation of ester, nitrogen containing compounds and acid were higher, while at higher temperatures (550 °C and 600 °C), the formation of oxygenated compounds were reduced and the production of hydrocarbons and alcohols increased. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Thermal pyrolysis of Cassia siamea was studied. • Maximum yield was 39.86 wt% of organic liquid (oil) and 10.35 wt% of aqueous liquid. • Pyrolytic oil was basic with a pH of 8.75 and calorific value of 30.18 MJ kg−1. • Pyrolytic oil includes phenols, aromatics, esters, alkanes, acids, and nitriles. • Pyrolytic char was rich in carbon (57.34%) with a calorific value of 21.894 MJ kg−1. Abstract Thermal pyrolysis of the Cassia siamea seed was carried out in a fixed bed reactor in the temperature range of 450 °C and 575 °C at a heating rate of 50 °C min−1. The reactor was maintained inert using nitrogen gas at a flow rate of 40 mL min−1. It was observed that the highest yield of pyrolytic liquid was 50.21% obtained at 550 °C which includes 39.86 wt% of organic liquid (oil) and 10.35 wt% of aqueous liquid. The fuel properties of pyrolytic oil confirmed that the oil was slightly basic with a pH of 8.75, having viscosity and calorific value of about 373 cSt and 30.18 MJ kg−1 respectively. The GC-MS based composition analysis quantified the occurrence of many valuable bio-chemicals such as heptadecanenitrile, 1,2-benzene dicarboxylic acid, butyl octyl ester, phenol, p-cresol as major compounds. [ABSTRACT FROM AUTHOR]

Brown coal is a soft sedimentary organic rock which is complex in nature and is the main source of energy production. In this work, we have studied the combustion and pyrolysis of brown coal using reactive molecular dynamic (MD) simulation. To make the large scale (above 1000 of atoms) reactive system practical, ReaxFF MD system was used which is 100 times faster than the methods of quantum mechanics (QM). To examine the pyrolysis/combustion process and initiation mechanism of brown coal, a fuel lean ( ϕ = 2), fuel rich ( ϕ = 0.5) and stoichiometric ( ϕ = 1) conditions were used in this work. The temperature used was high as per experimental reported condition so as to enable chemical reaction within a computationally affordable time. It was observed that the combustion of brown coal was initialized by thermal degradation subsequently forming small fragments. As the brown coal molecule oxidizes or thermally decomposes, hydrogen is abstracted and reacts with oxygen to form large amount of H 2 O molecules. Furthermore, the combustion of coal was also studied in the same conditions namely fuel rich, fuel lean and stoichiometric. Potential energy gradually decreases at high temperature while it was the reverse in pyrolysis. It was found that the effects of densities are lesser as compared to temperature. Some important intermediate like formaldehyde (HCHO) generated during the simulation reaction agreed well with the experimental data reported in literature. [ABSTRACT FROM AUTHOR]

• Hydro-deoxynation of pyrolytic oil has been reviewed. • Bio-oil stability parameters are studied and discussed in-depth. • Techn-economic analysis (TEA) of Hydro-deoxynation of pyrolytic oil is reviewed. • The influence of reactors types on HDO of pyroltic oil is also discussed. • HDO of pyrolysis oil is a feasible technology from the economic point of view. The rapid depletion of fossil fuels and environmental concerns have led researchers to explore alternative sources of energy. Pyrolytic oil derived from biomass is considered to be a potential alternative to fossil fuels, but it lacks certain physicochemical properties that make it unsuitable to be used as fuel. For instance, the high oxygen content in the pyrolytic oil exhibits chemical instability, the tendency to polymerize, and low energy density compared to traditional fuels. The hydrodeoxygenation (HDO) method is a viable technique to enhance the desirable characteristics of pyrolytic oil for commercial applications. This method has the disadvantage of catalyst deactivation owed due to coking, and its extent depends on the nature of oxy-compounds, catalyst type, and experimental conditions. However, by varying the experimental parameters such as catalyst acidity, temperature, pressure, solvent, and reaction time, the HDO product characteristics may be tailored to meet the specific requirements and applications. In this work, we have presented a comprehensive review of multiple alternatives to produce pyrolytic oil with essential fuel characteristics. The techno-economic analysis (TEA) and kinetic analysis of the pyrolytic oil were also elaborated. Overall, the review paper highlights the influence of process variables, kinetics investigation, reactor types and techno-economic analysis of HDO. [ABSTRACT FROM AUTHOR]

• Operative parameters of HTL substantially influence the property and yield of bio-crude. • HTL produced a higher viscosity bio-crude than pyrolysis. • Apart from the temperature, pressure, biomass to solvent ratio altered the bio-crude yield. • Bio-crude generated by HTL scores over pyrolysis except for higher sulphur, yield, and viscosity. • TEA and LCA established variations in yield and properties of fuels with varying operating conditions. An in-depth, comprehensive, and critical review of the hydrothermal liquefaction (HTL) technology for maximum yield of biocrude with enhanced properties has been undertaken. The feedstocks, process parameters, kinetic of HTL for bio-crude production have been systematically examined and collated from a board range of research. In the coverage of Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA) of HTL of feedstocks, this review overcomes the failure of existing literature to give due weightage to those crucial issues. HTL is introduced by the direct use of wet biomass that eliminates the drying unit, reduction in total expenditure, and conversion of materials into solid and liquid fuels at moderate temperatures (250–400 °C) and pressures (10–35 MPa). The introduction of hot pressurized water results in a lower yield of tar with higher energy proficiency. The biomass is delineated via elemental composition, renewable feedstock potential, and evaluation of dry versus wet biomass feedstocks. HTL is comprehensively reviewed through the process mechanisms, depolymerization reactions of biomass, hydrothermal liquefaction process of dry and wet lignocellulose feedstocks, and the effect of operating parameters. The product(s) description and evaluation, process advancements, energy efficiency, and kinetic investigation in relation to HTL form the final parts of this review. This review is aimed at optimization and commercialization of the HTL technology to meet the demands of the biofuel sector, the researcher working in the thermochemical conversion of feedstocks, and the development of new HTL reactors. [ABSTRACT FROM AUTHOR]