Co-pyrolyis of a binary mixture of date and cherry seeds was performed in a fixed-bed reactor, optimizing the experimental variables to obtain the maximum liquid fraction yield. The biochar produced was converted into activated carbon. Co-pyrolysis could be a successful means to upgrade the thermal pyrolysis of biowastes.

Abstract

The essential objective of this work was to co-pyrolyze a binary mixture of date and cherry seeds in a fixed-bed reactor. The experimental variables influencing the output of products, such as the pyrolysis temperature, pyrolysis duration, particle size, and heating rate, were optimized. The maximum liquid fraction yield (55.55 % with a bio-oil yield of 29.70 %) was attained at 500 °C for 60 min at a heating rate of 40 °C min⁻¹ and a particle size of 0.25 mm. The Fourier transform infrared and gas chromatography-mass spectrometry results revealed that the bio-oil was predominantly composed of oxygenated hydrocarbons, primarily higher acids (52.05 %), esters (23.67 %), and phenols (13 %). Biochar was converted into activated carbon, which possessed a Brunaer-Emmett-Teller surface area of 1055.55 m²g⁻¹. The amorphous structure of this carbon was confirmed by field emission-scanning electron microscopy and X-ray diffraction measurements.

The reliquefaction process of boil-off gas (BOG) in a propane plant was evaluated by utilizing a reverse Brayton cooling cycle and conducting simulations using Aspen HYSYS software. The operational parameters and system performance were assessed to uncover the key factors influencing BOG generation, energy consumption, and the coefficient of performance of the cycle.

Abstract

The reliquefaction process of boil-off gas (BOG) in a propane plant using the reverse Brayton cooling cycle was examined by simulating the operational parameters and system performance of a propane reliquefaction plant in Aspen HYSYS software. The simulation considered various process and design parameters and their effects on the BOG production rate, energy consumption demand, and coefficient of performance (COP) of the cycle. The results demonstrate that the inclusion of methane in the propane product has a considerable impact on the generation of BOG, but this comes at a cost because power consumption increases significantly and the cycle's COP decreases. Furthermore, heat transmission from the surrounding air through the tank insulation and the temperature at which propane is returned from the jetty influence the BOG generation.

The reaction of butanal with ethanol in the presence of Amberlyst-15 wet to form 1,1-diethoxybutane, which is a potential diesel additive, was optimized for maximum equilibrium conversion by a parametric study with temperature, reactants ratio, and catalyst loading as factors. Thermodynamic and kinetic studies were also carried out. The kinetic model was validated by means of the experimental data.

Abstract

1,1-Diethoxybutane is a high-potential biofuel additive that enhances various fuel properties, which include cetane number, lubricity, biodegradability, and flash point. This work presents a kinetic and thermodynamic study on the acetalization reaction between butanal and ethanol in the presence of Amberlyst-15 wet in a batch reactor. The experiments were conducted in the temperature range 313–333 K at atmospheric pressure with three different initial molar ratios of reactants and catalyst loadings. An optimal parameter setting to achieve maximum equilibrium conversion of butanal was derived from a parametric study with these three factors. The equilibrium constant for the reaction was determined. Standard thermodynamic properties of the reaction, such as enthalpy, entropy, and Gibbs free energy, were experimentally evaluated. The activity-based two-parameter Langmuir-Hinshelwood-Hougen-Watson rate expression was used for reaction kinetics. The activity coefficients were calculated by the UNIFAC method. The kinetic parameters and the activation energy were evaluated from the experimental data. The experimental data and data predicted by the model were found to be in good agreement.

A cyclone with a side-outlet configuration was analyzed by computational fluid dynamics simulation and validated with experimental results. The renormalization group k-ε model indicated a pressure drop of 80.8412 Pa and separation efficiency of 45.48 %. The operating pressure drop was one-third of the mathematical model result, while separation efficiency was 15 % lower than the experimental value.

Abstract

The side-outlet cyclone, featuring a novel geometric design with a lateral gas outlet, proves advantageous in space-constrained environments compared to traditional cyclones with top gas outlets. Herein, a cyclone separator with a side-outlet configuration was numerically investigated using the renormalization group k-ε model and pressure drop and separation efficiency as the performance parameters. Simulation results revealed that the side-outlet cyclone operates at a low to moderate pressure drop of 80.8412 Pa, with a removal efficiency of 45.48 %. The operating pressure drop was found to be only one-third of the computed pressure drop from mathematical modeling, with a removal efficiency 15 % lower than the experimental value. With varying cyclone design modifications, suitable experimental procedures and measuring approaches are desirable to further accurately corroborate these results.

Oil and gas refinery industry plant. Copyright: Shutter B/stock.adobe.com

Aqueous two-phase systems based on protic ionic liquids (PILs) allowed 250-fold concentration of hormones in both phases, and thus 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), and progesterone (PROG) were identified and quantified in water samples previously diagnosed as free of these micropollutants. The COSMO-RS method was used to understand hormone migration between the two phases.

Abstract

Estrogens are emergent pollutants found in low levels in water bodies, and for this reason they require concentration for quantification. In this study, aqueous two-phase systems (ATPSs) were used as an alternative strategy to improve hormone detection and quantification from real water samples. In addition, a predictive computational method (COSMO-RS) was used to understand better the migration of hormones between the two phases at the molecular level. Water samples previously analyzed as hormone-free were added to the 250-fold concentrated ATPS, where it was possible to detect and quantify concentrations of these micropollutants in the range of 9.3–29.19 ng L⁻¹.

A comprehensive review of all available physical, physiochemical, thermochemical, and biochemical techniques is given that are effectively applied for the production of biofuels (bioethanol, biodiesel, bio-oil, biochar, biogas, and other valuable chemicals) from biomass. The concept of waste-to-wealth in biomass conversion is emphasized whereby low-value biomass is transformed into high-value products.

Abstract

The discovery of new energy sources plays a vital role to fulfil the needs of energy and depletion of fossil fuel sources. An inclusive review of all available technologies for the synthesis of biofuels from biomass is presented. Amongst the innovative biomass conversion technologies, thermochemical technology encompasses significant potential practices and is required for expansion. Universally, biofuels are gaining importance due to the depletion of non-renewable fuel sources in transport and industries by equivalent work proficiencies. The reaction mechanism thoroughly explores all aspects associated with reaction conditions, types of reactor, and products. Biomass thermochemical conversion technologies will be influential in producing sustainable biofuels.

A simulation model of anaerobic digestion was developed, and sugarcane bagasse, rice straw, and sawdust were examined as feeds for the production of biohydrogen and methane. The operating parameters included in the study were pretreatment temperature, hydraulic retention time, and feed-to-water ratio. These parameters were optimized for better biohydrogen and methane yields.

Abstract

Biomass energy is a renewable energy source that is carbon-neutral, versatile, and can never go extinct. In the current study, a simulation model of an anaerobic digester with parameters such as pretreatment temperature (PTT), hydraulic retention time (HRT), and feed-to-water (F/W) ratio was developed and a design of experiment was created. The results showed that the higher hemicellulose content in sugarcane bagasse (SB) gave a decent H₂ yield (13–23 %). The significance sequence was PTT > F/W > HRT. The optimal values were HRT of 15–16 d; F/W of 1.5 (SB), 1.26 [rice straw (RS)], and 0.5 [sawdust (SD)]; and PTT of 63.3 (SB), 68.8 (RS), and 75 °C (SD). The optimal H₂ yield was 19.80 (SB), 20.94 (RS), and 21.41 % (SD). Therefore, the present simulation and optimization showed concrete results to raise H₂ yield.

The combustion process of a dual-fuel engine was studied by three different models. The peak pressure calculated by CFM is closest to the experimental values. EBM is the most accurate for CO₂ emissions. NO _x emissions calculated by CTM and EBM are in good agreement with experimental values at low and high speed, respectively. Hydrocarbon emissions calculated by CFM are the most accurate.

Abstract

The combustion process of a dual-fuel engine was calculated by characteristic timescale model (CTM), eddy breakup model (EBM), and coherent flamelet model (CFM) to verify the accuracy of the combustion models. The results show that the peak pressure calculated by EBM is 2.78 % higher than the experimental value, and the peak pressure calculated by CFM is closest to the experimental value. The EBM is the most accurate for CO₂ emissions. The deviation of CO emissions from the experimental values calculated by CTM is the smallest (< 1 %). The NO _x emission calculated by CTM is good agreement with the experimental value at low speed, and EBM is in best agreement with the experimental value at high speed. The hydrocarbon emission calculated by CFM is the most accurate, with a deviation of less than 0.6 %.

The application of the life cycle assessment technique for the acrylonitrile production from glycerol is proposed with propylene or glycerol as the main feedstock to compare the results, aiming at evaluating the environmental impacts generated in the process. The glycerol-based process from two sources (soybean, waste cooking oil) demonstrated promise in reducing fossil fuels and water consumption.

Abstract

Acrylonitrile is a monomer traded as a commodity on the global market with applications in several industrial sectors, produced from the ammoxidation of propylene. New technological alternatives are being studied, reducing the use of petroleum derivatives through renewable raw materials. This article proposes the application of the life cycle assessment technique for acrylonitrile production from glycerol, with the objective of evaluating the environmental impacts generated in the process. The results demonstrated that the use of glycerol from the state of Mato Grosso can reduce consumption of fossil fuel and water by 45 % and 31 %, respectively. The results about greenhouse gas (GHG) emissions were little significant when replacing the raw material.