No abstract

No abstract

No abstract

Gasification is a potential technology to convert municipal solid waste into energy in the form of syngas. Addition of air to the pyrolysis zone and oxidation was carried out by modifying a single-stage downdraft gasifier into a multistage air inlet. The results showed an increase in the syngas heating value and decreased tar content. To determine the performance, the effects of equivalent ratio, preheated air temperature, and air ratio were studied. When the equivalent ratio is increased, the flammable gas and LHV decrease. The optimum conditions were obtained for the equivalent ratio (ER) of 0.4, where the percentage of CO and H2 increased at an oxidation temperature of 902 °C. The variation of the air ratio has a stronger influence than the effect of the equivalent ratio because at the same equivalent ratio an increase in pyrolysis temperature of 674 °C is favorable to reforming tar from primary tar to secondary tar. The CO percentage increased significantly from 18.17% to 22.51%. Air preheating is useful to improve gasification performance, which was characterized by an increase in LHV from 5254 to 5976 kJ/kg. The optimum equivalent ratio and air ratio were 0.4 and 40:60, respectively, and effectively reduced the tar content from 50.02 to 27.82 mg/Nm3. The results of this study can be used to optimize multistage gasifier performance using air preheating and a multistage air inlet.

Abstract.A comparison synthetic strategy of Metal-Organic Frameworks, namely, Hongkong University of Techhnology-1 {HKUST-1[Cu 3 (BTC)] 2 } (BTC = 1,3,5-benzene-tri-carboxylate) through solvothermal and electrochemical method in ethanol:water (1:1) has been conducted. The obtained material was analyzed using powder X-ray diffraction, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA) and Surface Area Analysis (SAA). While the voltage in the electrochemical method are varied, ranging from 12 to 15 Volt. The results show that at 15 V the texture of the material has the best degree of crystallinity and comparable with solvothermal product. This indicated from XRD data and supported by the SEM image to view the morphology. The thermal stability of the synthesized compounds is up to 320 °C. The shape of the nitrogen sorption isotherm of the compound corresponds to type I of the IUPAC adsorption isotherm classification for microporous materials with BET surface area of 629.2 and 324.3 m²/g (for solvothermal and electrochemical product respectively) and promising for gas storage application. Herein, the methane storage capacities of these compounds are also tested.

Aggregates can be categorized into natural and artificial aggregates. Preserving natural resources is crucial to ensuring the constant supply of natural aggregates. In order to preserve these natural resources, the production of artificial aggregates is beginning to gain the attention of researchers worldwide. One of the methods involves using geopolymer technology. On this basis, this current research focuses on the inter-particle effect on the properties of fly ash geopolymer aggregates with different molarities of sodium hydroxide (NaOH). The effects of synthesis parameters (6, 8, 10, 12, and 14 M) on the mechanical and microstructural properties of the fly ash geopolymer aggregate were studied. The fly ash geopolymer aggregate was palletized manually by using a hand to form a sphere-shaped aggregate where the ratio of NaOH/Na2SiO3 used was constant at 2.5. The results indicated that the NaOH molarity has a significant effect on the impact strength of a fly ash geopolymer aggregate. The highest aggregate impact value (AIV) was obtained for samples with 6 M NaOH molarity (26.95%), indicating the lowest strength among other molarities studied and the lowest density of 2150 kg/m3. The low concentration of sodium hydroxide in the alkali activator solution resulted in the dissolution of fly ash being limited; thus, the inter-particle volume cannot be fully filled by the precipitated gels.

No abstract

The influence of the molar ratio H2O/SiO2 in the synthesis directly from Bangka Belitung’s Kaolin has been studied by performing synthesis of ZSM-5 with a variation of the molar ratio H2O/SiO2 is different at 15, 25, 30, and 35. Weighing 3.980 g Bangka’s kaolin are added other material so obtained molar composition 10Na2O: 120SiO2: 2Al2O3: 1800-4200H2O, and 1% of silicalite seed, subsequent hydrothermal process of 175°C for 24 hours. The result of solids was analyzed by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) and SEM EDX to the analyzed morphology of ZSM-5 crystal. The synthesis of ZSM-5 was directly optimum with molar ratio H2O/SiO2 of 30 having the highest cristallinity and largest crystal size of 59.44% and 3.795 µm, respectively.