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EN
The valorisation fine coal waste is still very limited in creating energy, especially syngas. This study aims to convert fine coal waste into synthetic gas via gasification using catalyst. Fine coal gasification takes place at 350–750 °C in an updraft gasifier using catalyst of 12.5–25 wt% natural zeolite. The research results show that the addition of zeolite has synergy with increasing temperature. The syngas produced at 750 °C and 12.5 wt% zeolite consisted of 32 vol% H2, 30.1 vol% CO, 27.7 vol% CH4 and 5.1 vol% CO2. The carbon conversion efficiency and high heating value (HHV) of synthetic gas are 88.34% and 18.97 MJ/Nm3. Fine coal has the potential to be reused as an energy source in the future.
EN
Starch can be found in microalgae, the raw material for the third generation of bioethanol production. One of them is C. pyrenoidosa. This study was conducted to analyze the effect of α-amylase enzyme concentration on the glucose contents produced and the effects of fermentation time on bioethanol contents produced. The hydrolysis process of this study was conducted using an α-amylase enzyme produced by A. niger. Several analyses in this research were carried out, including the analysis of enzyme activity using the Fuwa method, the analysis of glucose levels from enzymatic hydrolysis using the DNS method, and the analysis of bioethanol contents using the density method and GC-MS. The highest glucose content was 0.67 mg/mL, which was obtained from the addition of 40% (v/w) α-amylase enzyme, and the yield of bioethanol content from the sample treated 40% (v/w) α-amylase enzyme and fermented for 9 days was the optimum, which produced 28.07% of bioethanol content.
EN
The utilisation of fine coal waste is still limited, even though its availability is very abundant in the mining industry. This study utilises fine coal by converting it into syngas through catalytic gasification. The gasification process was carried out at a temperature range of 350–550°C for 10–50 minutes using natural zeolite as a catalyst. The syngas composition and quality parameters were evaluated through the H2/CO ratio, heating value, and gasification efficiency. From the research results, fine coal contained high amounts of carbon and fixed carbon. Temperature is the variable that most influences the gasification process. The addition of zeolite actively increased the CO content in the syngas. The H2/CO ratio of syngas >1, the highest HHV and LHV 16.15 and 14.46 MJ/Nm3 with the highest carbon conversion efficiency value of 88.85%, made fine coal very suitable to be used as raw material for the gasification process to produce environmentally friendly syngas.
EN
Modification of bentonite by the Al/Fe metal oxide pillarization process was carried out with metal oxides. The bentonite pillars were successfully characterized using an X-Ray Diffraction (XRD) spectrophotometer. The results of XRD characterization showed the peak diffraction angle (2θ) in metal-pillared bentonite was 26.84° at 698.98 cps. Meanwhile, in thermally and chemically activated bentonite, the peak angles were marked at 20.64° and 26.7°. There is a shift in the peak angle after activation and pillarization. XRD patterns showed dioctahedral smectite and quartz accessory minerals.
EN
This study successfully synthesized a core-shell-shell in the form of CoFe2O4-SiO2-TiO2 catalyst magnetic and recyclable. The catalyst was employed for the photocatalytic degradation of methyl orange (MO) dye. Subsequently, the catalyst was subjected to XRD, FTIR, SEM-EDS, VSM, as well as UV-DRS characterizations. The photocatalytic degradation was studied as a function of the solution pH, MO concentration, and irradiation time, while the kinetics of photocatalytic degradation and the catalyst reusability were also evaluated. On the basis of the XRD, FTIR, and SEM-EDS characterizations, the CoFe2O4 coating was successfully carried out using SiO2 and TiO2. CoFe2O4-SiO2-TiO2 was discovered to possess magnetic properties with a saturation magnetization of 17.59 emu/g and a bandgap value of 2.4 eV. The photocatalytic degradation of MO followed the Langmuir-Hishelwood model. The optimum degradation was obtained at the MO concentration of 25 mg/L, solution pH of 4, catalyst dose of 0.05 g/L, irradiation time of 160 minutes, MO removal efficiency achieved 93.46%. The regeneration study showed CoFe2O4-SiO2-TiO2 after 5 cycles were able to catalyze the photocatalytic degradation with an MO removal efficiency of 89.96%.
EN
The presence of CO2 in the syngas is attracting more attention in terms of reducing the greenhouse gas emissions in its utilisation. The aim of this study was to purify syngas from the CO2 content of fine coal gasification. Fine coal is gasified with and without absorption using CaO, which is hydrated to Ca(OH) 2 in the modified updraft gasifier at 450–700 °C. Apart from investigating the CO2 absorption process, the gasification process also evaluates the influence of temperature in terms of its synergy with Ca(OH) 2. The best conditions for the gasification process are achieved at 700 °C. The content of CO2 was proven to be well absorbed, which is characterised by a decrease in the CO2 content and an increase in H2 in syngas. After the absorption process, the H2 content obtained increased from 42.6 mole% to 48.8 mole% of H2 at 700°C. The H2 ratio also increased after absorption to 2.57 from the previous value of 2.23. The highest absorption efficiency of CO2 by Ca(OH) 2 occurred at 700°C at 50.63%. With an increase in temperature in the gasification process with absorption, the CO2 content decreased dramatically from 16.9 mole% to 3.9%. Ca(OH) 2 has good absorption power at CO2 at high temperatures.
EN
The rapid progress of the CPO industry in Indonesia is not in line with good waste management and utilization. Palm empty fruit bunch, as the first waste from the CPO production process in Indonesia, is mostly piled on the ground. Palm empty fruit bunch must be processed to reduce pollution and increase its use-value. This study aimed to convert oil palm empty fruit bunches solid waste through the gasification process using Indonesia’s natural zeolite into synthesis gas. Gasification takes place at 350–550°C by added 12.5% wt zeolite using a modified updraft gasifier. Good results were achieved at 550°C with a gas composition of 22.64% vol CH4, 29.22% vol CO, and 3.4% vol H2. The gasification efficiency is evaluated through carbon conversion efficiency (CCE) and cold gas efficiency (CGE). Both the highest CCE and CGE were found at 550°C by 95.74% and 81.65% respectively. The results showed that the gasification temperature has the greatest influence in driving higher carbon conversion to syngas and palm empty fruit bunches are very suitable for conversion into environmentally friendly syngas in the CPO industry.
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