Crude glycerol as a potential feedstock for future energy via thermochemical conversion processes: a review.

Biodiesel is an emerging substitute for petroleum-based products. It is considered an ecologically safe and sustainable fuel. The high cost of biodiesel production is linearly related to its feedstock. Crude glycerol, which is a by-product of the biodiesel industry, is also a major challenge that must be addressed. A large volume of crude glycerol needs to be disposed of, and this involves processing, dumping, and land requirements. This increases the cost of biodiesel production. One way to decrease the cost of biodiesel production is to utilize its by-product to make valuable products. Crude glycerol can be processed to produce a variety of chemicals and products. The present utilization of crude glycerol is not enough to bring down its surplus availability. Thermochemical conversion processes can utilize crude glycerol as a starting feedstock and convert it into solid, liquid, and gaseous fuels. The utilization of crude glycerol through integrated thermochemical conversion processes could lead to an integrated biorefinery. This review paper highlights the research scope for areas where crude glycerol could be utilized as a feedstock or co-feedstock in thermochemical conversion technology. Various thermochemical conversion processes, namely, gasification, pyrolysis, combustion, catalytic steam reforming, liquefaction, and supercritical water reforming, are discussed and shown to be highly suitable for the use of crude glycerol as an economical feedstock. It is found that the integration of crude glycerol with other thermochemical conversion processes for energy production is a promising option to overcome the challenges related to biodiesel production costs. Hence, this paper provides all the necessary information on the present utilization status of crude glycerol in thermochemical conversion processes, as well as identifying possible research gaps that could be filled by future research studies

Rheological Characterization of Clay-PolyesterComposites

AbstractPolymer-clay composites, which consist of clay particles dispersed in a polymeric matrix, have been used in different applications. Clay fillers are widely used in polymers as ways to produce cost-effective, strong, and energy efficient materials. The compounding and inclusion of particulate fillers in the polymers to get a homogenous material is a rather complex process. The processing of these materials, like mixing and moulding is strongly dependent on the particle-particle and particle-polymer interactions. Therefore, the fundamental understanding of the rheological properties of the polymer-clay composites is very important in the design of their processing. In this study, the rheological behaviour of bentonite clay dispersed in unsaturated polyester was investigated. Herschel-Bulkley model and Structural Kinetic model were used to describe the dependence of the apparent viscosity of the composite on shear rate and shearing time, respectively. The effects of the filler/polyester ratio and filler size on the rheological properties of the composite were studied

Synergic interactions, kinetic and thermodynamic analyses of date palm seeds and cashew shell waste co-pyrolysis using Coats–Redfern method

Date palm and cashew shell wastes are abundant byproducts of the agriculture industry in the UAE, but they are often underutilized and not adequately managed, resulting in environmental problems. For the first time, co-pyrolysis of these wastes was studied to investigate their physicochemical properties, synergistic interaction, thermal degradation behavior, and estimate kinetic and thermodynamic parameters using thermogravimetric analysis with non-isothermal heating rates from 20 to 800 °C and a heating rate of 10 °C/min. The Coats and Redfern method, utilizing twenty-one solid-state reaction mechanisms, was used to perform analyses. The three diffusion models showed the best linear regression with the experimental thermogravimetric data. Co-pyrolysis of cashew shells with date seeds significantly lowered the activation energy (Ea) and produced stable biochar, providing an opportunity to obtain pyrolysis products at better energy efficiency. The estimated Ea for 100% date seeds, 100% cashew shells, and their blend (50:50) were 109, 124, and 113 kJ/mol, respectively. The thermodynamic parameters (ΔH, ΔG, and ΔS) indicated that the pyrolysis process was endothermic but not spontaneous. The novelty of this work lies in investigating the potential of utilizing two underutilized wastes together to produce pyrolysis products. This study is essential for advancing co-pyrolysis of date seeds and cashew shell wastes, optimizing product yields, and understanding their pyrolysis behavior towards experimental pyrolysis

Crude Glycerol as a Potential Feedstock for Future Energy via Thermochemical Conversion Processes: A Review

Biodiesel is an emerging substitute for petroleum-based products. It is considered an ecologically safe and sustainable fuel. The high cost of biodiesel production is linearly related to its feedstock. Crude glycerol, which is a by-product of the biodiesel industry, is also a major challenge that must be addressed. A large volume of crude glycerol needs to be disposed of, and this involves processing, dumping, and land requirements. This increases the cost of biodiesel production. One way to decrease the cost of biodiesel production is to utilize its by-product to make valuable products. Crude glycerol can be processed to produce a variety of chemicals and products. The present utilization of crude glycerol is not enough to bring down its surplus availability. Thermochemical conversion processes can utilize crude glycerol as a starting feedstock and convert it into solid, liquid, and gaseous fuels. The utilization of crude glycerol through integrated thermochemical conversion processes could lead to an integrated biorefinery. This review paper highlights the research scope for areas where crude glycerol could be utilized as a feedstock or co-feedstock in thermochemical conversion technology. Various thermochemical conversion processes, namely, gasification, pyrolysis, combustion, catalytic steam reforming, liquefaction, and supercritical water reforming, are discussed and shown to be highly suitable for the use of crude glycerol as an economical feedstock. It is found that the integration of crude glycerol with other thermochemical conversion processes for energy production is a promising option to overcome the challenges related to biodiesel production costs. Hence, this paper provides all the necessary information on the present utilization status of crude glycerol in thermochemical conversion processes, as well as identifying possible research gaps that could be filled by future research studies

High-performance, renewable thermal insulators based on silylated date palm fiber–reinforced poly(β-hydroxybutyrate) composites

Developing insulating materials with minimal environmental impacts and enhanced properties has been the primary challenge in recent years. To address these challenges, date palm fiber (DPF) was treated with a silane coupling agent 3-aminopropyl triethoxysilane and two grafting solvents (acetone and ethanol) via the wet chemical method. The treated fibers were used to prepare poly(β-hydroxybutyrate) (PHB)-based composites via melt blending, thermo-compression molding, and annealing. The insulation properties of these green composites revealed that the silylated fiber composites possess an appropriate thermal conductivity, of 0.0901–0.106 W/(m·K). In cold and hot water, the silylated fiber composites drastically decreased water absorption by 20% and 34%, respectively. The tensile strength of the silylated fiber composites reached 18 MPa owing to improved compatibility, and the highest compressive strength was 48.6 MPa with a filler content of 40 wt%. The heat of combustion for silylated fiber composites ranged from 20.79 to 21.94 MJ/kg. The results indicate that silylated DPF-based PHB composites have potential for use in building engineering

The Effect of Alkaline Treatment on Poly(lactic acid)/Date Palm Wood Green Composites for Thermal Insulation

In this work, the effect of alkaline treatment on the thermal insulation and mechanical properties of date palm wood fibers (DPWF) and polylactic acid (PLA) green composite was studied. Alkaline treatment was applied to DPWF using two different solutions: sodium hydroxide (NaOH) and potassium hydroxide (KOH), with concentration of 2 vol.%. The fibers were later incorporated into PLA with weight percentages from 10 to 40 wt.%, to form three composite types: PLA with untreated fibers (PLA-UTDPWF), PLA with KOH treated fibers (PLA-KOH), and PLA with NaOH treated fibers (PLA-NaOH). The prepared composites were for use as a green thermal insulation material. The composites were tested to assess the effect of treatment on their physical (density and degree of crystallization), thermal (thermal conductivity, specific heat capacity, thermal diffusivity, thermal degradation, glass transition, and melting temperature), and mechanical properties. Moreover, the composite structural characteristics were investigated using FTIR and SEM analysis. The alkaline treatment significantly increased the crystallinity of the composites, specifically for higher filler loadings of 30 and 40 wt.%. The crystallinity for the 40 wt.% increased from 33.2% for PLA-UTDPWF, to 41% and 51%, for PLA-NaOH and PLA-KOH, respectively. Moreover, the alkaline treatment reduced the density and produced lighter composites than the untreated specimens. For instance, the density of 40 wt.% composite was reduced from 1.43, to 1.22 and 1.30 gcm3 for PLA-NaOH and PLA-KOH, respectively

Date Palm Surface Fibers for Green Thermal Insulation

Some of the major challenges of the twenty-first century include the continued increase in energy consumption and environmental pollution. One approach to overcoming these challenges is to increase the use of waste materials and environmentally friendly manufacturing methods. The high energy consumption in the building sector contributes significantly to global climatic changes. Here, by using date palm surface fibers, a high-performance green insulation material was developed via a simple technique that did not rely on any toxic ingredients. Polyvinyl alcohol (PVA) was used as a binding agent. Four insulation samples were made, each with a different density within the range of 203 to 254 kg/m3. Thermal conductivity and thermal diffusivity values for these four green insulators were 0.038–0.051 W/m·K and 0.137–0.147 mm2/s, respectively. Thermal transmittance (U-value) of the four insulation composites was between 3.8–5.1 W/m2·K, which was in good comparison to other insulators of similar thickness. Thermogravimetric analysis (TGA) showed that insulating sample have excellent thermal stability, with an initial degradation temperature of 282 °C, at which just 6% of its original weight is lost. Activation energy (Ea) analysis revealed the fire-retardancy and weakened combustion characteristics for the prepared insulation composite. According to differential scanning calorimetry (DSC) measurements, the insulating sample has a melting point of 225 °C, which is extremely close to the melting point of the binder. The fiber-based insulating material’s composition was confirmed by using Fourier transform infrared spectroscopy (FTIR). The ultimate tensile range of the insulation material is 6.9–10 MPa, being a reasonable range. Our study’s findings suggest that developing insulation materials from date palm waste is a promising technique for developing green and low-cost alternatives to petroleum-based high-cost and toxic insulating materials. These insulation composites can be installed in building envelopes during construction