Browsing by Author "Kariim, Ishaq"

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Catalytic hydrothermal liquefaction of orange peels into biocrude: An optimization approach by central composite design
(Elsevier B.V., 2023-08) Kariim, Ishaq; Waidi, Yusuf; Swai, Hulda; Kivevele, Thomas
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.
Catalytic hydrothermal liquefaction of orange peels into biocrude: An optimization approach by Central Composite Design
(Elsevier B.V., 2023-06-01) Kariim, Ishaq; Waidi, Yusuf; Swai, Hulda; Kivevele, Thomas
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 oC) 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 oC 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.
Catalytic hydrothermal liquefaction of orange peels into biocrude: An optimization approach by central composite design
(Elsevier, 2023) Kariim, Ishaq; Waidi, Yusuph; Swai, Hulda; Kivevele, Thomas
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.
io-Oil Upgrading over ZSM-5 Catalyst: A Review of Catalyst Performance and Deactivation
(wiley, 2023-12-27) Kariim, Ishaq; Swai, Hulda; Kivevele, Thomas
Due to population explosion and industrialization, waste biomass and polymer conversion into biofuel has attracted the interest of researchers. The application of the ZSM-5 catalyst for bio-oil upgrading into renewable biofuels has attracted researchers’ efforts as an excellent catalyst. The need for improved biofuel quality with reduced oxygenates has further necessitated the application of catalyzed upgrading techniques. The catalytic performance of the ZSM-5 catalyst was attributed to its exceptional pore structure and window architecture and when it is incorporated with some selected transition metals to improve aromatic hydrocarbon formation. The review revealed that the development of coke deposit on the microspores of the ZSM-5 catalyst hindered the effective transport of large molecular compounds into the active sites for an easy deoxygenation process. Hence, the introduction of mesoporosity, hybrid catalyst development, and tailored crystal growth on the ZSM-5 catalyst could address several hindrances associated to conventional ZSM-5. Therefore, the need for catalyst modification is paramount for ZSM-5 performance during bio-oil upgrading.
Optimization of solvothermal liquefaction of water hyacinth over PTFE-acid mediated kaolin catalyst for enhanced biocrude production
(Elsevier, 2024-03-01) Kariim, Ishaq; Bakari, Ramadhani; Waidi, Yusuf; Kazmi, Wajahat; Swai, Hulda; Kivevele, Thomas; Malla, Sunita
The invasive nature of water hyacinth and the need for renewable energy sources have necessitated this research. Catalyst development through enhanced pore structure and process parameters optimization are requirements for effective mass transport during the biomass valorization and improved biocrude formation during solvothermal liquefaction process. In this present study, the effects of temperature (250–340 °C), residence time (10–20 min) and catalyst loading (10–13 wt%) on biocrude, biochar, gas yield, and biomass conversion were optimized using a Box-Behnken experimental design. The developed catalyst through the application of polytetrafluoroethylene (PTFE) for pore structure enhancement was characterized using SEM, BET and XRD techniques. The process optimization found maximum biocrude yield (32.0 wt%), minimum biochar yield (19.4 wt%) and maximum conversion efficiency (80.6%) at 340 °C, 20 min residence time, and 13 wt% catalyst loading. The GC-MS result of the biocrude produced at the optimum conditions (13 wt% catalyst loading) consists of ketones (32.2%), acids (22.3%) and had 65.2% carbon, 7.3% hydrogen, HHV of 29.4 MJ/kg and H/C ratio of 1.34 while an increment in catalyst loading of 20 wt% enhanced the overall biocrude properties with HHV of 35.50 MJ/kg. This result depicts the suitability of the PTFE modified acid treated kaolin for high quality biocrude production through valorization of water hyacinth into a candidate for renewable energy material.
Recent advances in thermochemical conversion of biomass into drop-in fuel:a review
(Elseiver, 2022) Kariim, Ishaq; Swai, Hulda; Kivevele, Thomas
The global evolutional changes towards the use of renewable energy sources for trans- portation purposes are on the increase in an attempt to mitigate the environmental haz- ard and the proposed depletion associated with fossil fuel resources. Pyrolysis and hy- drothermal processes of biomass conversion into renewable biofuels are resulted into the production of biocrude with high oxygen content due to the presence of large amount of oxygenates in biomass feedstocks. The presence of oxygen content in bio-oil causes cor- rosion, low heating value, instability and high viscosity in bio-oil. These challenges have necessitated the application of upgrading techniques such as catalytic hydrodeoxygenation process among others. The presence of several oxygenated compounds made the mech- anisms of bio-oil synthesis difficult and model bio-oil were reviewed to understand the effects of process parameters and catalysts on aromatic selectivity and conversion. The se- lectivity of aromatic hydrocarbons was affected by deactivation of catalysts’ active sites. Coke formation has been identified as one of the common and notorious causes of cata- lysts’ deactivation which is dependent on the nature of feedstock, conditions of operation and the nature of catalyst. Therefore, the need to develop, evaluate a structurally and ther- mally stable catalyst with high catalyst recovery and reusability are of importance in the quest to depict hydrodeoxygenation process as an excellent technique for bio-oil upgrad- ing
Recent advances in thermochemical conversion of biomass into drop-in fuel:a review
(Elsevier B.V., 2022-09) Kariim, Ishaq; Swai, Hulda; Kivevele, Thomas
The global evolutional changes towards the use of renewable energy sources for trans- portation purposes are on the increase in an attempt to mitigate the environmental haz- ard and the proposed depletion associated with fossil fuel resources. Pyrolysis and hy- drothermal processes of biomass conversion into renewable biofuels are resulted into the production of biocrude with high oxygen content due to the presence of large amount of oxygenates in biomass feedstocks. The presence of oxygen content in bio-oil causes cor- rosion, low heating value, instability and high viscosity in bio-oil. These challenges have necessitated the application of upgrading techniques such as catalytic hydrodeoxygenation process among others. The presence of several oxygenated compounds made the mech- anisms of bio-oil synthesis difficult and model bio-oil were reviewed to understand the effects of process parameters and catalysts on aromatic selectivity and conversion. The se- lectivity of aromatic hydrocarbons was affected by deactivation of catalysts’ active sites. Coke formation has been identified as one of the common and notorious causes of cata- lysts’ deactivation which is dependent on the nature of feedstock, conditions of operation and the nature of catalyst. Therefore, the need to develop, evaluate a structurally and ther- mally stable catalyst with high catalyst recovery and reusability are of importance in the quest to depict hydrodeoxygenation process as an excellent technique for bio-oil upgrad- ing.
Recent advances in thermochemical conversion of biomass into drop-in fuel:a review
(Elsevier, 2022) Kariim, Ishaq; Swai, Hulda; Kivevele, Thomas
The global evolutional changes towards the use of renewable energy sources for trans- portation purposes are on the increase in an attempt to mitigate the environmental haz- ard and the proposed depletion associated with fossil fuel resources. Pyrolysis and hy- drothermal processes of biomass conversion into renewable biofuels are resulted into the production of biocrude with high oxygen content due to the presence of large amount of oxygenates in biomass feedstocks. The presence of oxygen content in bio-oil causes cor- rosion, low heating value, instability and high viscosity in bio-oil. These challenges have necessitated the application of upgrading techniques such as catalytic hydrodeoxygenation process among others. The presence of several oxygenated compounds made the mech- anisms of bio-oil synthesis difficult and model bio-oil were reviewed to understand the effects of process parameters and catalysts on aromatic selectivity and conversion. The se- lectivity of aromatic hydrocarbons was affected by deactivation of catalysts’ active sites. Coke formation has been identified as one of the common and notorious causes of cata- lysts’ deactivation which is dependent on the nature of feedstock, conditions of operation and the nature of catalyst. Therefore, the need to develop, evaluate a structurally and ther- mally stable catalyst with high catalyst recovery and reusability are of importance in the quest to depict hydrodeoxygenation process as an excellent technique for bio-oil upgrad- ing.
Solvothermal liquefaction of orange peels and catalytic upgrading of biocrude into transportation fuel over a hybrid catalyst
(NM-AIST, 2024-08) Kariim, Ishaq
The efficient valorization of biomass for energy-derived biocrudes is essential for effective waste management. However, the production of biocrudes with high energy and reduced oxygen contents during the liquefaction process requires further improvement. This study investigates the impact of reaction temperature, residence time, and ratio of ethanol to acetone on the energy compositions and bio-product’s yield enhancement were investigated under non catalytic and catalytic process with further upgrading. The biocrudes obtained via the non catalytic liquefaction were characterized for elemental composition, bio-oil compositions, functional group, molecular weight and thermal stability to understand the effects of process parameters on the biocrudes’ compositions. An improved bio-oil with High Heating Value (HHV) (38.18 MJ/kg) and lower oxygen: carbon (O/C) ratio (0.11) were obtained at 430 ◦C, 35 min and 50% ethanol with a significant boost in the enhancement factor, deoxygenation, and percentage hydrogenation of 2.63, 36.88%, and 77.87%, respectively. The presence of ketones with composition of 32.58 area% suggests the needs for the removal of oxygen from the bio-oil. Using a central composite design (CCD), catalyst dosage (3-6 wt.%) and reaction temperature (330-430°C) were optimized, maintaining constant orange feedstock weight (10g), reaction time (15 minutes), and a solvent ratio of 3:1 (acetone to ethanol). Optimal biofuel yield (71.09 wt.%), solid residue (28.18 wt.%), biomass conversion (71.82 wt.%), and gas yield (40.14 mL/g) were achieved at 430°C and 3 wt.% catalyst loading. The Fe/CNSs catalysts possess high selectivity to acid formation. High correlation coefficients indicated the model’s strong fit with experimental data. The hydrodeoxygenation (HDO) of cyclohexanone under both catalytic and non-catalytic conditions involved mechanisms such as hydrogenation, decarboxylation, decarbonylation, and dehydration. The NiCeMo catalysts shows an even particle dispersion where 11.3 area % of hydrocarbon and highest conversion of ketones and phenols were obtained. However, the performance of NiCeMo catalysts for HDO was hampered by the Guerbet reaction, which led to the formation of side products which are primarily alcohols. Modifying the acidity and using water as a solvent could potentially increase the HHV of the biofuel hence, promote the usage for transportation purposes. Biofuel produced through the non-catalytic process demonstrated a higher energy value of 38.18 MJ/kg, highlighting orange peels as a viable renewable energy resource
Solvothermal liquefaction of orange peels into biocrude: An experimental investigation of biocrude yield and energy compositional dependency on process variables
(Elsevier, 2024-01) Kariim, Ishaq; Park, Ji-Yeon; Kazmi, Wajahat; Swai, Hulda; Lee, In-Gu; Kivevele, Thomas
The efficient valorization of biomass for energy-derived biocrudes is essential for effective waste management. However, the production of biocrudes with high energy and reduced oxygen contents during the liquefaction process requires further insight. Therefore, the impact of reaction temperature, residence time, and ethanol: acetone on the energy compositions and bioproduct’s yield enhancement were investigated. The biocrudes obtained were characterized using elemental analysis, GC–MS, FTIR, GPC and TGA to understand the effects of process parameters on the biocrudes’ compositions. An improved HHV (38.18 MJ/kg) and lower O/C ratio (0.11) were obtained at 430 °C, 35 min and 50% ethanol with a significant improvement in the enhancement factor, deoxygenation, and percentage hydrogenation of 2.63, 36.88%, and 77.87%, respectively. The presence of ketones, hydrocarbons, phenolics and aromatics of 23.74, 4.28, 37.20 and 17.81% respectively indicate the potential of the obtained biocrude as renewable energy sources upon further upgrading.
Solvothermal liquefaction of orange peels into biocrude: An experimental investigation of biocrude yield and energy compositional dependency on process variables
(Elsevier, 2024-01) Kariim, Ishaq; Park, Ji-Yeon; Kazmi, Wajahat; Swai, Hulda; Lee, In-Gu; Kivevele, Thomas
The efficient valorization of biomass for energy-derived biocrudes is essential for effective waste management. However, the production of biocrudes with high energy and reduced oxygen contents during the liquefaction process requires further insight. Therefore, the impact of reaction temperature, residence time, and ethanol: acetone on the energy compositions and bioproduct’s yield enhancement were investigated. The biocrudes obtained were characterized using elemental analysis, GC–MS, FTIR, GPC and TGA to understand the effects of process parameters on the biocrudes’ compositions. An improved HHV (38.18 MJ/kg) and lower O/C ratio (0.11) were obtained at 430 °C, 35 min and 50% ethanol with a significant improvement in the enhancement factor, deoxygenation, and percentage hydrogenation of 2.63, 36.88%, and 77.87%, respectively. The presence of ketones, hydrocarbons, phenolics and aromatics of 23.74, 4.28, 37.20 and 17.81% respectively indicate the potential of the obtained biocrude as renewable energy sources upon further upgrading.
Solvothermal liquefaction of orange peels into biocrude: An experimental investigation of biocrude yield and energy compositional dependency on process variables
(Elsevier, 2024-01) Kariim, Ishaq; Park, Ji-Yeon; Kazmi, Wajahat; Swai, Hulda; Lee, In-Gu; Kivevele, Thomas
The efficient valorization of biomass for energy-derived biocrudes is essential for effective waste management. However, the production of biocrudes with high energy and reduced oxygen contents during the liquefaction process requires further insight. Therefore, the impact of reaction temperature, residence time, and ethanol: acetone on the energy compositions and bioproduct’s yield enhancement were investigated. The biocrudes obtained were characterized using elemental analysis, GC–MS, FTIR, GPC and TGA to understand the effects of process parameters on the biocrudes’ compositions. An improved HHV (38.18 MJ/kg) and lower O/C ratio (0.11) were obtained at 430 °C, 35 min and 50% ethanol with a significant improvement in the enhancement factor, deoxygenation, and percentage hydrogenation of 2.63, 36.88%, and 77.87%, respectively. The presence of ketones, hydrocarbons, phenolics and aromatics of 23.74, 4.28, 37.20 and 17.81% respectively indicate the potential of the obtained biocrude as renewable energy sources upon further upgrading.