Papers by Keyword: Steam Reforming

Abstract: Natural gas has diverse content such as Methane, Ethane, Carbon dioxide, Hydrogen Sulfide, and other gases. In addition, natural gas is formed over a very long time, where it comes from fossil fuels. Natural gas that has been treated and produced products are called synthesis gas which can be used to make ammonia (NH₃). To produce ammonia, steam compounds (H₂O) are used which are reacted with natural gas to produce hydrogen (H₂) and Nitrogen (N₂) obtained from the air. Ammonia manufacturing can be done by several processes, namely desulfurization (natural gas purification), Steam Reforming, Shift Converter, CO₂ removal, methanation, and refrigeration units. The data used in this simulation is data on the ammonia plant at PT. Petrokimia Gresik. What is seen from this simulation is the influence of the composition of natural gas with variations in composition, namely 75% – 99% methane. The largest yield was obtained in the composition of 75% methane with an ammonia product yield of 82.34 tons/hour, this is because the division of the composition is divided propositionally into other compounds such as ethane, and propane, i-butane, etc. which have more H₂ content. Then there is the ratio of methane flow rate to steam using a variation of 1:3.5 - 1:7.5 where the largest ammonia product is obtained from a ratio of 1:7.5 with ammonia product yields of 84.79 tons/hour because more and more steam causes the formation of more hydrogen. Furthermore, there is a ratio of methane flow rate to air with a variation of 1:5.5 - 1:7.5 where the largest ammonia product is obtained from a ratio of 1:5.5 with an ammonia product yield of 84.87 tons/hour because the air content consists of N₂ and O₂, where if the O₂ content is a lot it will react with Methane so that the H₂ produced will be less if methane reacts also with O₂ not only with H₂O.

Abstract: A solid oxide fuel cell (SOFC) is known as an interesting energy conversion device because of its fuel flexibility and high efficiency. The hydrogen-rich stream is used as fuel carrier converting to generate electrical energy. A non-stoichiometric thermodynamic model based on minimum free energy was performed to predict the amount of hydrogen production via the methanol reforming under supercritical water (SCW) condition. The effects of SCW reaction temperature and water-to-methanol molar ratio on the SOFC power generation integrated with SCW reforming from methanol were investigated. The hydrogen yield, the required heat duty for a feed preheater and a SCW reactor and the SOFC power generation increase with increasing the SCW reaction temperature and the amount of water fed in SCW reactor. Under operating parameters of SCW reformer based on 1 mole/sec of methanol fed at the high temperature of 1273 K and water-to-methanol molar ratio of 5, the SOFC electrical power of 246 kW was produced with the maximum fuel utilization of 0.7.

Abstract: The Ni catalysts supported by CeO₂-Al₂O₃ xerogel were prepared by sol-gel method. The effect of hydrolysis ratio (R at 16.5 and 165) on CeO₂-Al₂O₃ textural properties and phase formation were investigated. The results revealed that the porous texture and the Ni crystalline phase can be controlled by adjusting the hydrolysis ratio. A high surface area and small Ni crystallite size were obtained by using the hydrolysis ratio of 16.5. For hydrogen production via glycerol steam reforming, the Ni catalyst supported on CeO₂-Al₂O₃ xerogel showed a better catalytic performance than that supported on commercial alumina. The promoted Ni catalyst supported on commercial alumina suddenly deactivated after first 12 h, whereas that on Al₂O₃ xerogel performed the catalytic stability more than 20 h. This demonstrated that the catalyst prepared by sol-gel method is an interesting catalyst for using in the glycerol steam reforming because of the catalytic stability enhancement.

Abstract: The study focuses on hydrogen production via glycerol steam reforming over copper and nickel loaded on HZSM-5 zeolite based catalyst. The catalysts were prepared by using different loading amount of copper (0-10wt%) and nickel (0-10wt%) on HZSM-5 zeolite catalysts through wet impregnation method and was characterized by X-Ray Diffraction (XRD). The performances of catalysts were evaluated in terms of glycerol conversion and hydrogen production at 500°C using 6:1 of water to glycerol molar ratio (WGMR) in a tubular fixed bed reactor. All the catalysts had achieved more than 85% of glycerol conversion except that of 5%Cu loaded on HZSM-5 catalyst. The addition of nickel into 5% Cu/HZSM-5 catalyst had increased the hydrogen yield. Similar trend was observed when copper was added into Ni/HZSM-5 catalyst but using copper loaded on HZSM-5 alone was unable to produce hydrogen compared to using nickel catalyst alone. It showed that copper acted as a promoter for hydrogen production. It was established that a 5wt% of Cu with 10wt% of Ni loaded on HZSM-5 catalyst showed significant improvement in terms of hydrogen yield and gaseous product compositions at selected operating conditions.

Abstract: A nickel nanowire catalyst was prepared by a hard templating method, and characterized by transmission electron microscopy (TEM), N₂ physical adsorption, X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD) and H₂ temperature-programmed reduction (H₂-TPR). The catalytic properties of the nanowire catalyst in the ethanol steam reforming were compared with a metallic Ni catalyst which was prepared with nickel sponge. The characterization results showed that the nickel nanowire catalyst had high specific surface area and there was more NiO phase in the nickel nanowire catalyst than in the metallic Ni catalyst. The reaction results showed that the nickel nanowire catalyst had higher ethanol conversion and hydrogen yield than the metallic Ni catalyst.

Abstract: Steam reforming of ethanol has been carried out using a commercial catalyst (Hi-FUEL) of calcium doped nickel/alumina catalyst. Hi-FUEL had successfully reformed ethanol into the desired products at relatively high yield and selectivity. The hydrogen yield of 90.5% has been achieved from this catalyst with almost no ethylene detected. Hi-FUEL is also comparable with other calcium doped nickel/alumina catalyst as reported by other researchers.

Abstract: In this paper the catalytic steam reforming of glycerol to H2 has been evaluated in the presence of Mo/γ-Al2O3 and Mo/γ-Al2O3-MgO in a fixed-bed microreactor at 700 oC. Physiochemical properties of the Mo catalysts were explored by various analytical techniques such as N2 adsorption–desorption (BET), X-ray diffraction (XRD), X-ray fluorescence spectrum (XRF), Temperature-programmed reduction (TPR) and Transmission Electron Microscopy (TEM). Mo/γ-Al2O3-MgO catalysts show promising results with higher H2 concentration produced as compared to Mo/γ-Al2O3 catalysts. The Mo was found to be uniformly distributed on the surface of γ-Al2O3-MgO support and addition of MgO contents into γ-Al2O3 improves the dispersion of Mo on the surface of the support.

Abstract: Catalytic steam reforming of acetic acid using bimetallic catalysts of 5 wt.% nickel and 5 wt.% cobalt supported on Lanthanum (III) oxide (La₂O₃) for hydrogen production was investigated in a micro fixed bed reactor. The reactor was of quartz tube with a 10 mm inside diameter. The effect of catalyst dilution on the reaction was studied. Silicon carbide was used as the dilution material. The experiments were conducted at atmospheric pressure and temperatures ranging from 500 to 700°C. The complete conversion of acetic acid to product gases has been observed at 550°C and 700°C for diluted and non-diluted catalysts respectively. It shows that catalyst dilution had a profound effect on the conversion of acetic acid at low temperature (550°C) whilst high temperature of 700°C was required for the non-diluted catalyst. The product gas distributions are similar when using both diluted and non-diluted catalysts.

Abstract: For biomass gasification, the high tar and carbon monoxide contents and the low heat value of fuel gas are problems to be solved, which leading to the poor operating conditions of the completed projects in China. Therefore, a new technology of biomass oxygen-enriched gasification in pressurized fluidized bed is proposed. Coupling the technologies of pressurized biomass oxygen-enriched gasification at low temperature, high-temperature gasification and melting, steam reforming and hydrocarbon synthesis, the high gasification efficiency, tar cracking and gas reforming shall be realized, and the middle/high heat value gas which meets the national standards will be produced. ASPEN PLUS simulation was carried out for biomass oxygen-enriched gasification. Both the equivalent ratio and gas yield of rice husk are lower than that of the wood sawdust, while the gas calorific values are equivalent. Considering the gas yield, the calorific value and economy, the optimum operating conditions are obtained: the gasification temperature at 1200 °C, the oxygen purity at 0.9, the equivalent ratio at about 0.25, the S/B ratio at 0.1~0.2. The gas yield could reach 1.9 m³/kg, and the gas calorific value was above 11 MJ/m³.

Abstract: The reaction thermodynamics of sorption enhanced steam reforming (SESR) of acetic acid as a model compound of bio-oil for hydrogen production were investigated and contrasted with acetic acid steam reforming (SR). The most favorable temperature for SR is approximately 650 °C. However, the optimum temperature for SESR is around 550 °C, which is about 100 °C lower than that for SR. The highest hydrogen concentration from SR is only 67%, which is below the basic requirement of hydrogen purity for fuel cells. In SESR, hydrogen purities are over 99% in 500-550 °C with a calcium oxide to acetic acid molar ratio (CAMR) of 4 and a water to acetic acid molar ratio (WAMR) greater than 6. The results show that hydrogen production from sorption enhanced steam reforming of acetic acid should be a promising direction.