Papers by Keyword: CaO

Abstract: Biodiesel is an environmentally friendly and renewable alternative fuel; however, it continues to face technical challenges related to oxidative stability, combustion efficiency, and exhaust emissions. One widely studied solution involves the use of fuel additives, particularly calcium oxide (CaO). CaO possesses strong basicity, high thermal stability, and notable catalytic activity, making it applicable in both the production and application stages of biodiesel. As a heterogeneous catalyst, CaO accelerates the transesterification process, enhancing biodiesel conversion efficiency. It also acts as an adsorbent, removing water, free fatty acids, and other impurities, thereby improving fuel purity and storage stability. Moreover, CaO contributes to more efficient combustion and has been shown to reduce emissions of carbon monoxide and particulate matter. Despite these benefits, challenges remain, including the risk of residue formation and engine deposits. Recent studies highlight the superior performance of CaO, particularly in nanoparticle form, compared to other inorganic additives. Future research should focus on surface modification strategies, dosage optimization, and long-term engine performance assessments. With proper engineering approaches, CaO holds significant potential to support the development of more efficient, stable, and sustainable biodiesel formulations for cleaner energy applications.

Abstract: This study presents the preliminary characterization of commercial calcium oxide (CaO) and aluminum oxide (Al₂O₃) catalysts intended for application in the catalytic upgrading of biomass-derived bio-oil. The catalysts were characterized using Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, Thermo gravimetric Analysis (TGA), and X-ray Diffraction (XRD). SEM images revealed that both catalysts exhibit irregular, rough-surfaced particles with visible fractures and mesostructured textures conducive to catalytic activity. BET results indicated a specific surface area of 50.301 m²/g for CaO and 129.442 m²/g for Al₂O₃, with corresponding pore diameters of 2.64 nm and 2.647 nm, respectively, confirming their mesoporosity. TGA of CaO showed substantial weight loss associated with moisture, hydroxide, and carbonate decomposition, indicating the need for pre-calcination to restore active oxide phases. In contrast, Al₂O₃ exhibited minor mass loss mainly due to dehydration and dehydroxylation of surface-bound species. XRD analysis confirmed the presence of crystalline γ-Al₂O₃ and highly crystalline CaO with characteristic diffraction planes for their respective phases. These findings demonstrate that both commercial catalysts possess favorable physicochemical properties particularly high surface area, thermal stability, and mesoporous structure that make them promising candidates for vapor-phase upgrading in biomass pyrolysis systems.

Abstract: Dolomite is widely used in the construction, glass ceramics, iron and steel, pharmaceutical industries, as a source of CaO and MgO and as thermal energy storage material. Thermal decomposition analysis of natural dolomite of the so-called Jeddih limestone has been carried out. A thermogravimetry analysis (TGA) in the air evaluates the thermal decomposition of dolomite. The natural dolomite has been analyzed by x-ray flourescence (XRF) and x-ray diffraction (XRD) to test crystal structure and decomposition phase, fourier transform infra-red (FTIR) was utilized to identify the presence of functional groups. The particle morphology was observed by scanning electron microscopy. TGA curve shows that the thermal decomposition of dolomite occurs in two stages. The first stage is in temperature range of 600 - 779°C and the second one is at the temperature 779°C. The results are in line with the XRD and FTIR measurements. Which shows that calcite begins to grow at a temperature of 600°C and MgO phase is observed at 700 - 900°C. Moreover, CaO phase starts to be found at 800°C.

Abstract: Heterogeneous catalyst has been viewed as a promising catalyst for biodiesel production. This study employed Turritella terebra (TT) shell as a source for synthesizing heterogeneous CaO catalyst for biodiesel production via transesterification by utilizing chicken fat as a feedstock. The TT shell CaO catalyst was characterized and its catalytic performance was studied. The spectrographic methods that include FTIR, SEM, PSA, and BET-BJH were employed for characterization of the synthesized CaO. The TT shell CaO catalyst optimally produced chicken fat biodiesel (CFB) with reaction parameters at catalyst concentration of 4 wt%, chicken fat to methanol molar ratio of 1:12, reaction temperature of 60°C, and reaction time of 90 min. The optimal yield was 94.03% and the TT shell CaO catalyst still yield 79.19% of CFB on the fifth cycle of reaction. This study has implied that TT shell is a feasible and attractive renewable source of heterogeneous CaO catalyst for biodiesel production.

Abstract: In this paper, the cockle shell was studied as a catalyzer for biodiesel production. The cockle shell was heated at the various temperatures from 200 to 1300 °C for 4 h in the furnace. Then, the crystal structure and function group of unheated and heated cockle shell were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. The results indicated that the initial phase of cockle shell is aragonite phase. After heat at 400 °C, the aragonite phase transformed to calcite phase. Moreover, the calcite phase of cockle shell was completely changed to calcium oxide (CaO) after heated at 800 °C. Eventually, the yield of biodiesel used the CaO derived from cockle shell were determined by nuclear magnetic resonance spectroscopy (NMR). The results show that the CaO derived from cockle shell can be used as a catalyzer of biodiesel preparation. However, the biodiesel used CaO from cockle shell after heated at 1100 to 1300 °C as a catalyzer have the higher yield than other heated temperature. Finally, the results of this research indicated that the CaO from cockle shell could be used as a catalyst for biodiesel production.

Abstract: Using high temperature fly ash for his pozzolan properties to cement composite production is known a few years ago. New ways combustion of fossil fuels also creates a new type of fly ash, named fluidized bed combustion fly ash. However, this fly ash has same pozzolan properties as has high temperature fly ash, this type is not using for production of cement composites. Fluidized bed combustion fly ash has highly variable chemical composition but usually it has a higher amount of free CaO together with sulphates. This higher amounts of free CaO after mixing of fluidized bed combustion fly ash with water to some extent becomes an activator for the beginning of the pozzolanic reaction, during which is consumed the extinguished CaO. If there is also present high temperature fly ash in cement composite, it could be accelerated his pozzolanic reaction in the same manner using a fluidized bed combustion fly ash. In this experiment was tested a synergy effect in the use of fluidized bed combustion fly ash with high temperature fly ash as an additive. The experiment was carried out on cement pastes that have been studied in particular the progress of hydration processes, pointing to a possible acceleration of pozzolanic reactions of both types of fly ash.

Abstract: AZ31magnesium alloys with initially added (0.5, 1, 1.5) wt.% CaO particles were cast, hot extruded, and oxidized between 450 and 650°C in atmospheric air. Initially added CaO particles reacted with the AZ31 melt, and precipitated as Al₂Ca along the grain boundaries of the α-Mg matrix. They increased the oxidation resistance of the AZ31 alloys. The more CaO particles was, the better the oxidation resistance of the alloys was. During oxidation, MgO oxide scales that incorporated CaO formed at the surface of the AZ31 alloys.

Abstract: Selective non-catalytic reduction (SNCR) is a denitration method in the high temperature area, and NH₃ or urea is used for SNCR as reducing agents to react with NO_X to produce N₂ in the flue gas in the temperature ranged from 850°C to 1100°C. The SNCR deNOx technology has been well used in utility boiler, but compared with it, the lower denitration efficiency and the larger consumption of ammonia indicate a more complex process in cement pre-calciner. Unlike in utility boiler, the presence of high concentrations of cement raw materials may influence SNCR denitration reaction process in cement kilns. Therefore, studying the effect of CaO which occupy the major composition of cement raw material is very important in SNCR process. In this study the influence of CaO on the SNCR deNOx process was investigated by simulating SNCR reaction at temperature that ranges from 750°C to 1100°C with different normalized stoichiometric ratio. The experimental results demonstrate that the addition of CaO increases the optimum denitration temperature to 1100°C, but it has no effect on normalized stoichiometric ratio. In the whole reaction process NH₃ not only restores NO to O₂ but also reacts with O₂ to NO. Since the adsorption of NH₃ on CaO surface, in the temperature range of 750°C-850°C the addition of CaO promotes the reaction of NH₃ and O₂ and increases NO_X concentration. However, in the temperature range of 850°C-1000°C it not only promotes NH₃ oxidation but also inhibits the reduction reaction of NH₃, thereby the denitration reaction is inhibited. In the temperature range of 1050°C-1100°C the denitration reaction is promoted due to the NH₃ desorption from CaO surface.

Abstract: This paper investigates the properties of Sago pith waste ash (SPWA) from agricultural waste using different calcination temperatures (500°C, 700°C and 1000°C). Chemical characteristic of SPWA was first investigated by using X-ray fluorescence (XRF) followed by XRD analysis as a verification of the mineralogical phases present in the SPWAs. Based on the analysis, the major compositions of SPWA are found to be CaO and SiO₂ with other minor oxides such as MgO, Fe₂O₃ and Al₂O₃. Both CaO and SiO₂ are very significant oxides that can be used as an alternative binder in the synthesis of ceramic materials and geopolymer. Moreover, the presence of these oxides are consistent for SPWA calcined from 500°C, 700°C and 1000°C. Phase transformation such as quartz, calcite and magnesite that can be found in 500°C and 700°C whilst new phases such as wollastonite, fayalite and cristobalite in 1000°C proved that SPWA beneficial to be used as a new material resources especially in the ceramic and geopolymer applications.

Abstract: In Malaysia, due to abundance of oil palm waste, it is a good candidate to be used as a feedstock for syngas and hydrogen production. Biomass steam gasification is one of the promising methods for syngas production. This work focuses on the steam gasification with in-situ CO₂ capture using CaO as absorbent materials for hydrogen production from palm oil empty fruit bunch (EFB). Three parameters (temperature, steam/biomass ratio and sorbent/biomass ratio) has been studied on the lower heating value (LHV) and higher heating value (HHV) of product gas. The results shows that the current study gives higher value of LHV at lower temperature of 823K. The higher value of LHV is obtained due to the lower concentration of CO₂ caused by using CaO as sorbent material. Furthermore, CaO materials enhanced the concentration of concentration of the CO, H₂ and CH₄ in the product gas. The results are also compared against published data as well.