Synthesis Gas Production Research Articles

Synthesis gas production from chemical looping gasification of lignite by using hematite as oxygen carrier

Chemical looping gasification (CLG) of lignite by using hematite oxygen carrier is performed to achieve high purity synthesis gas. The oxygen carrier reaction performance as well as the effects of temperature and lignite/oxygen carrier ratio on the syngas evaluation are investigated by TG and fixed bed reactor coupling with various analytical methods. The experimental results reveal that the hematite oxygen carrier consisting primarily of Fe2O3, SiO2 and Al2O3 presents three H2 reduced peaks at 472.59 °C, 634.17 °C and 849.01 °C respectively, corresponding to the crystal form transition from Fe2O3 to Fe. Lignite pyrolyzes preferentially to generate intermediates then further reacts with oxygen carrier to produce synthesis gas in CLG process, following the oxygen carrier reaction path of Fe2O3 → Fe0.963O → Fe2O3. Oxygen carrier plays a key role in promoting lignite conversion to synthesis gas in CLG process owing to the lattice oxygen shifting reactions equilibrium to the direction of syngas production. Excessive lattice oxygen is beneficial to CLG reaction until the L/O ratio reaches to 4/6 with the limitation of heat and mass transfer in reaction system. However, the minimum value of O/L is 2/8, which ensures the oxygen carrier makes obvious promotion effect in reaction process. High temperature improves synthesis gas yield and carbon conversion by enhancing endothermic reactions in CLG process. The hematite oxygen carrier recovers main crystalline phase after the CLG process without serious sintering.

Experimental investigation of synthesis gas production by methane reforming with flue gas over a NiO-Al2O3 catalyst: Reforming characteristics and pressure drop

An experimental investigation of methane reforming with flue gases obtained by combustion of methane with the ratio of air to methane of 1 is carried out over NiO-Al2O3 catalyst. The set of experiments was conducted to understand the effects of operational parameters such as temperature, pressure, residence time and inlet gas composition on the conversion of the reactants and the yields of products. It is found that at the residence time above 4 kgcat s/mol the methane conversion has a value close to equilibrium. A change in pressure from 1 to 5 bar has a negligible effect on methane conversion, not more than 1–2% for various operating parameters. The steam addition to the inlet reaction gas mixture increases the methane conversion considerably; especially at the temperature range from 500 to 800 °C. The steam addition to the inlet mixture has a notable on synthesis gas composition, especially at the temperature range below 700°C. Moreover, the experiments have been carried out to determine the pressure drop and the loss factor in a packed-fixed bed of a methane reformer. A characteristic quadratic dependence of the pressure loss versus velocity ΔP=f(v2) is observed for all experiments.

Simulation and Optimization of Chlorella vulgaris Gasification Using Aspen Plus

Microalgal gasification produces synthesis gas (syngas), liquid products (e.g., tar), and solid carbon (e.g., char). However, at the current state, the viability of the process is yet to be established. One of the ways to achieve that is by understanding the fundamental of microalgal gasification. This could be done by optimizing the process conditions via modeling. Therefore, this study models the microalgal gasification process and further optimizes its process conditions. The modeling work was carried out using Aspen Plus V8.8 software, where thermodynamics equilibrium and kinetics approaches were used in the calculations of Chlorella vulgaris gasification. The study was done by modeling the gasifier in three stages: drying, pyrolysis, and gasification. The model was developed using proximate and ultimate analysis data of Chlorella vulgaris. The parameters were temperature (600–1000 °C), equivalence ratio (ER) 0.1–0.4, and mass flow rate of biomass (10–100 kg/h). The syngas yields of H2, CO, CO2, and CH4 were determined and the findings were compared with the literature and some deviations of the predicted syngas compositions were presented. It was found that consistent results of syngas composition and yield were obtained between the model and the experiments. The root mean square error (RMSE) values for the effect of temperature were 0.242, 0.294, 0.228, and 0.062 for H2, CO, CO2, and CH4, respectively. Meanwhile, for the effect of loading, the values were 0.083, 0.064, 0.362, and 0.479 for H2, CO, CO2, and CH4, respectively. The optimization of the gasification from sensitivity analysis results showed that the increment of temperature favored the H2 and CO production, and the increased in biomass loading favored H2 and CH4 production. Meanwhile, the increment of ER value resulted in increasing the CO2 yield. Based on the findings, a slight deviation in the simulation results was observed compared with the experimental work. This might be resulted from the limitation of the Aspen Plus V8.8 software where some parameters need to be set as a constant value, which in this study was the heating rate.

Syngas Production via Combined Steam and Carbon Dioxide Reforming of Methane Over Ni-Mo-Sb/Al₂O₃ Catalysts.

The combined steam and carbon dioxide reforming of methane (CSCRM) reaction was studied over a series of Ni-Mo-Sb catalysts to produce synthesis gas (H₂/CO). The catalysts modified with varying contents of antimony oxide (0-5 wt%) were prepared by the impregnation method. The catalytic reaction was conducted at 900 °C and 1 atm with a feed ratio of CH₄:CO₂:H₂O:Ar = 1:0.8:1.3:1 and WHSV = 40,000 h-1. The catalysts were characterized using N₂ Adsorption Desorption, X-ray diffraction (XRD), H₂-Temperature Programmed Reduction (H₂-TPR), Thermogravimetric analysis (TGA) and Transmission Electron Microscope (TEM). The highest catalytic activity and long-term stability were obtained over a Ni-Mo(1)-Sb(3)/Al₂O₃ catalyst and the superior catalytic behavior was closely related to the strong resistance to carbon formation.

Catalytic methane reforming into synthesis gas over developed composite materials prepared by combustion synthesis

In this work, the results of carbon dioxide reforming and partial oxidation of CH4 on the catalysts prepared by solution combustion synthesis (SCS) and impregnation of moisture capacity methods are presented. Investigation of the activity of catalysts produced from initial mixture of Co(NO3)2-Μg(NO3)2-H3BO3 and glycine/urea of different composition was carried out for the production of synthesis gas and comparison of carbon dioxide reforming and partial oxidation of methane. Co(ΝΟ3)2 + Mg(NO3)2 + H3BO3 catalyst containing glycine has a higher activity than the catalyst containing urea. The CH4 conversion reaches 54.6%, and the conversion of CO2 increases to 51.7%, while the yield of H2 and CO is 54.1% and 51.3%, respectively, at 900 °C. It was found that CoMg3O4 spinel formation is due to magnesium cations substitution of cobalt cations. Mg2+ ions are replaced by ions of Co2+, as a consequence CoMg3O4 lattice parameters increase, since the ionic radius of Mg2+ (0.66 A) less than Cο2+ (0.72 A). Some advantage of SCS catalysts in comparison with catalysts prepared by the traditional impregnation method in the processes of dry reforming and partial oxidation of methane was shown.

Modeling and Comparison a Thermally Coupled Reactor of Methane Tri – Reforming and Dehydrogenation of Cyclohexane Reactions for Syngas Production in Both Co- & Counter-Current Modes

Abstract The aim of this work is a comparison of different inlets (Co- and Counter-current modes) to feed a thermally coupled reactor (TCR) in producing syngas as a valuable chemical. The novel thermally coupled reactor has been designed as a double pipe reactor where tri-reforming of methane for syngas production has been considered in the exothermic side of fixed bed plug reactor, and dehydrogenation of cyclohexane reaction occur in the endothermic side. The heat generated in the exothermic part by the walls of the tube side is transferred to the endothermic section. A steady-state homogeneous one-dimensional model predicts the performance of this reactor for simultaneous production of synthesis gas and benzene in an economical approach for both co- and counter-current modes of operation. The reversed flow of cyclohexane has been considered for the counter-current flow regime. The simulation results of co- and counter-current modes of TCR and also an optimized tri-reforming of methane (OTRM) single reactor are investigated and compared with each other. The results showed that methane conversion, hydrogen yield and ${H_2}/Co$ ratio in the exothermic side of TCR reached to 91.1 %, 1.82 and 2.1 in co-current mode and 87.8 %, 1.77 and 2.3 in counter-current mode, respectively. Additionally, the results showed that cyclohexane conversion at the endothermic side of the reactor in co- and counter-current modes achieved to 98.6 % and 99.9 %, respectively. So, the results for counter-current mode showed superior performance in hydrogen and benzene production in the endothermic side of TCR. Also, Changes in various operating parameters during the reactor have been studied.

Composite Rh/Zr0.25Ce0.75O2-δ-ƞ-Al2O3/Fecralloy wire mesh honeycomb module for natural gas, LPG and diesel catalytic conversion to syngas

The reactions of catalytic autothermal and steam conversion of n – C16H34 (model compound simulating diesel fuel), and partial oxidation of natural gas and LPG were studied using 0.24wt%Rh/(12wt%Zr0.25Ce0.75O2-δ-ƞ-Al2O3)/Fecralloy wire mesh honeycomb modules. The experiments were carried out in a flow setup in the temperature range of 550–960 °C and at atmospheric pressure. It was shown that the observed syngas (CO + H2) productivities were 65 and 53 m3Lcat−1h−1 (STP) at GHSV of 100,000 and 80,000 h−1 in natural gas and liquid petroleum gas catalytic partial oxidation processes, respectively. The product distributions were still close to the calculated equilibrium values. The catalyst activity was very high and, potentially, the maximum syngas productivity may even exceed experimentally demonstrated values.It was shown also that 0.24wt%Rh/(12wt%Zr0.25Ce0.75O2-δ-ƞ-Al2O3)/Fecralloy catalyst provided complete n-hexadecane conversion with the maximum syngas (CO + H2) productivity of 6.2 m3Lcat−1h−1 (STP) at GHSV of 13,300 h−1. The proposed concept of hydrogen-rich gas production from various hydrocarbon feedstocks in a multi-fuel catalytic reformer over single composite catalyst was proved feasible. The produced synthesis gas can be supplied as a fuel for power generation units based on high-temperature solid oxide fuel cells.

Prospects of Base Oil Production by GTL Technology in Russia

The article discusses the potentials of production of base oils in Russia by GTL technology. The quality of the base oils produced currently in Russian enterprises are analyzed. The possibility of producing base oils by the GTL process, taking account of the analysis of data on synthesis gas production by various conversion methods and the experience of application of GM process in foreign enterprises, is discussed. The experience of using different types of Fischer-Tropsch synthesis reactors is analyzed and, based on the obtained data, recommendations are offered for their use in Russia.

Hazards associated with syngas storage

Energy needs of many countries are largely covered by energy obtained from fossil fuels. This in turn involves environmental pollution and greenhouse gas emissions. The growing environmental awareness and the need to prevent climate changes mean that clean energy and alternative energy sources are still a significant research issue. One of the most important technologies for efficient and low-carbon energy generation is the gasification process and synthesis gas production. Worldwide, there are now more than 270 such installations. More installations are under construction. Syngas is a mixture of hydrogen and carbon monoxide. Depending on the feedstock, it can also contain smaller amounts of carbon dioxide, methane and nitrogen. The gasification process consists of four stages: syngas production, storage, transport and utilization, e.g. as fuel. Because syngas is mainly composed of flammable and toxic gases, in the event of an uncontrolled release into the atmosphere these processes may pose a potential hazard to humans and the environment. The paper presents the results of analyses related to hazards resulting from an uncontrolled release of gas at the stage of the gas storage, before it is transported or finally used. Hazard scenarios are presented and the probability of their occurrence as well as the consequences for humans and the environment are determined.

In situ catalyst exsolution on perovskite oxides for the production of CO and synthesis gas in ceramic membrane reactors

In situ exsolution of nickel nano-particles on both sides of ceramic membrane reactors to accelerate the co-production of CO and synthesis gas through CO2 splitting and CH4 partial oxidation, respectively.

The Effect of Operating Temperature and Equivalence Ratio in an Entrained Flow Gasification of EFB

Abstract Biomass is a renewable and sustainable source of energy that can be used to generate electricity and other forms of power. Rapid economic growth in developing countries, growing energy demand, high dependence on global and local transportation, pollution, depletion of sources, and endangered national security of energy importing countries have raised the awareness of the need for non-fossil based renewable energy sources. This paper presents the effect of operating temperature and equivalence ratio (ER) on the gasification of empty fruit bunch (EFB) in an entrained flow reactor. EFB is one of the most abundant biomass source in Malaysia, being the second largest palm oil processing nation in the world. The temperature ranges of between 700 °C to 900 °C and ER of 0.2 to 0.4 were studied to find the most optimum condition for biomass gasification in an entrained flow gasification system. It was found that the production of synthesis gas increases as the temperature increased, along with the carbon conversion and higher heating value of gas product. The most optimum operating temperature and ER for biomass gasification in the entrained flow gasifier were found at 900°C and 0.3 respectively.

Gas-to-Liquids (GTL) Plant Optimization Using Enhanced Synthesis Gas Reforming Technology

This paper evaluates method for optimisation of GTL plant using Steam/CO2 reforming for syngas generation. Extensive modelling of GTL plant has been done. Two cases were considered during the simulation of the GTL plant. The first case was the use of oxygen gas as the feed reactant gas using an auto-thermal reformer for the production of synthesis gas. The alternative case which is the proposed method uses CO2 in lieu of oxygen for the production of synthesis gas. CO2 method was chosen because of its cheap availability and the ability to be recycled from purge gas and reused reducing pollution. Honeywell’s Unisim software was used for the simulation and the Peng Robinson equation of state was chosen as the fluid property package. The simulation was done unit by unit and integration of all units was made. The synthesis gas unit was simulated in Unisim as a conversion type reactor using two separate reactors while three equilibrium reactors were used to control the water gas shift reaction to maintain favourable H2/CO ratio. The FT reactor was modelled as a multi-tubular bed reactor and simulated as a plug flow reactor (PFR) in Unisim using heterogeneous catalytic reaction type. Technical and economic performances were analyzed for both methods. The technical analyses revealed that the proposed steam/CO2 method gave a H2/CO ratio of 2.17 as against the 2.21 gotten for the ATR. Furthermore, the carbon efficiency of the two methods revealed 77.68% and 92.17% for base case and the proposed methods respectively showing that the proposed case has higher efficiency. The liquid yields show that the proposed method has a liquid yield of 5730b/d over the 5430b/d gotten from the base case representing an increase in product yield of 5.5%.

Обоснование требований к точности расходомеров-регуляторов систем управления комплексами получения синтез-газа

Обоснование требований к точности расходомеров-регуляторов систем управления комплексами получения синтез-газа

Effect of support materials on the performance of Ni-based catalysts in tri-reforming of methane

Tri-reforming of methane (TRM) utilizing CO2, H2O and O2 is an emerging technique for the production of synthesis gas and CO2 abatement. Nevertheless, formulation and design of low-cost, active and stable catalyst for TRM is a major challenge due to its complex reaction network and rapid catalyst deactivation. The support effect is a critical factor influencing the activity and stability of supported Ni catalyst. Thus, a series of supported Ni catalysts over different metal oxides such as Al2O3, ZrO2, TiO2, SBA-15, MgO and CeO2-ZrO2 were prepared. The catalysts were characterized by using N2 - physisorption, XRD, EDX, SEM, TEM, TPR, CO2 – TPD, NH3 – TPD, H2 – pulse chemisorption and TGA. The performance of these catalysts was evaluated at 800 °C, 1 atm, WHSV 17220 mL h−1 g−1 and molar feed composition CH4:CO2:H2O:O2:N2 = 1:0.23:0.46:0.07:0.28 in a fixed-bed reactor. The initial activity of these catalysts followed the order: Ni/Al2O3 > Ni/SBA-15 > Ni/ZrO2 > Ni/CeO2-ZrO2 > Ni/TiO2 > Ni/MgO. Ni/Al2O3 derived from spinel precursor NiAl2O4 resulted in well-dispersed smaller Ni particles, stronger metal-support interaction, a higher degree of reducibility and higher basic sites concentration, which led to its superior activity with 8.72 × 10−2 mmol/gcat·s, 2.31 × 10−2 mmol/gcat·s and 4.2 × 10−2 mmol/gcat·s CH4, CO2, and H2O conversion rate respectively. On the contrary, the stability of SBA-15 and ZrO2 supported Ni catalysts was remarkably high. Hexagonal porous network of SBA-15 confined Ni particles that resulted in high resistance against metal sintering and carbon deposition whereas Ni/ZrO2 offered resistance to Ni re-oxidation owing to its oxophilic property. Experimental investigations reveal that Ni/TiO2 and Ni/MgO resulted in poor CH4, CO2 and H2O conversion rates for TRM due to lower degree of reducibility. Furthermore, Ni/CeO2-ZrO2 catalyst had weak metal-support interaction as observed from TPR studies. Due to larger Ni crystallite size, it exhibited lower conversion compared to Ni/Al2O3, Ni/SBA-15, and Ni/ZrO2.

Energy and economic aspects of synthesis gas production from oil sludge and plastic waste

A series of experiments have been performed to investigate the influence of reaction temperature, the equivalence ratio (ER), and blending ratio on the gas composition, tar content and higher heating value (HHV) of synthesis gas. H2 content decreased from 10.7 to 8.2% in the range of BR while CO and CH4 increased from 17.4 to 23.1% and 3.4 to 6.3%, respectively. HHV increased with BR and H2/CO showed an opposite trend. The highest HHV and H2/CO were obtained at 100%PW and 100%OS, respectively. Tar content increased from 4.8 to 9.5 g/Nm3 with BR increasing in the range because of a reduction in the endothermic nature of volatile combustion.

Reactivity of Co-doped Ca2Fe2O5 brownmillerite oxides as oxygen carriers for microalgae chemical looping gasification

Chemical looping gasification (CLG) is a promising technology to covert solid fuel into synthesis gas efficiently, and oxygen carrier is crucial for CLG. In this work, Co-doped Ca2Fe2O5 brownmillerite oxides were synthesized, and its reactivity as oxygen carriers for microalgae CLG was investigated. The results showed that the Cobalt substitution for Fe improved the activity of oxygen carriers, but excess Cobalt tended to complete oxidation. XPS analysis, thermogravimetric and fixed bed tests indicated that Cobalt doping enhanced the activity of Fe cations in brownmillerite structure, and Ca2Fe1.8Co0.2O5 was proved to be most suitable for microalgae CLG with the highest H2 yield. In the initial 10 redox cycles, gasification performance with Ca2Fe1.8Co0.2O5 oxygen carrier almost kept stable, and the gasification efficiency and carbon conversion respectively dropped by 3.96% and 2.34%, although impurity phase of spinel oxide and agglomeration was detected. In summary, Ca2Fe1.8Co0.2O5 kept great activity and acceptable stability for synthesis gas production through microalgae CLG.

Analysis of the Synthetic Gas Production from Saw Dust Gasification

Aims: Produce combustible gas from sawdust for domestic house use.
 Study Design: A fluidized bed gasifier suitable for sawdust gasification was used.
 Place and Duration of Study: The study was done at the federal university of technology akure, Ondo state Nigeria
 Methodology: Sawdust was first processed by converting it to pellets. Tests were carried out on the pellets using a bomb calorimeter using the ASTM-E771 standard. On experimental, the pellets were loaded into the reactor and then fired. Air was forced into the plenum, after which the air distributor plate evenly distributed jets of air in the bed resulting in complete and incomplete combustion.
 Results: Experimental tests showed that the pellets have a heating value of 16.36 MJ of energy per kg and a higher percentage of volatile matter of 57.62% (ASTM-E872) and a lower percentage of fixed carbon than the initial sawdust sample. The produced synthesis gas composed of methane 63.4%, Ammonia 1.09%, Carbon monoxide 0.63%, Hydrogen sulphide 0.84% and carbon dioxide 34.04%.
 Conclusion: The gas was ignited showing it was combustible.

A Highly Efficient Integrated Power and Technological Natural Gas Utilization System for Producing Electricity, Heat, and Synthetic Liquid Fuel with Partially Sequestering Carbon Dioxide Emissions into the Atmosphere

This article presents a description and comparative analysis of an integrated natural gas utilization technology for concurrently producing electricity and synthetic liquid engine fuel and partially sequestering carbon dioxide. In the daytime, the installation produces electricity, heat, and methanol. In the night-time hours of minimum load, CO2 is partially captured from flue gases and is converted in a plasmatron to obtain H2 + CO by adding natural gas and steam. The produced synthesis gas is forwarded to a catalytic synthesis reactor for boosting the operation of the methanol producing installation. In comparison with state-of-the-art installations for separate production of electricity, heat, and methanol, the proposed installation makes it possible to save about 20% of natural gas and decrease the amount of CO2 emissions into the atmosphere by as much as 30%.

Review on synthesis gas production in a downdraft biomass gasifier for use in internal combustion engines in Nigeria

This paper presents a review on the possibility and potential of synthesis gas production and its utilization as an alternative fuel for internal combustion engines (ICE) in Nigeria. Information on numerous experimental studies and demonstrations on downdraft biomass gasification for synthesis gas production as well as the potential use of synthesis gas as fuel for ICE applications were assessed. The review reveals that there are abundant biomass resources in Nigeria and there is a great potential to produce synthesis gas from these sources using downdraft gasifier as preferable technology. Keywords: Biomass, Downdraft gasifier, internal combustion engines, Synthesis gas

Heat Transfer Modeling of a High-Temperature Porous-Medium Filled Solar Thermochemical Reactor for Hydrogen and Synthesis Gas Production

In this paper, heat transfer modeling of a high-temperature porous-medium filled solar thermochemical reactor for hydrogen and synthesis gas production is investigated. The numerical simulation is performed using a three-dimensional (3D) numerical model and surface-to-surface radiation model coupled to Rosseland approximation for radiation heat transfer. The effects of operating conditions and the porous structural parameters on the reactor thermal performance were investigated significantly. It was found that large axial temperature gradient and high-temperature distribution throughout the reactor were strongly dependent on the operating conditions. The inlet gas temperature has remarkable effects on the temperature distribution. The thermal performance of porous-medium filled solar thermochemical reactor could be improved by preheating the inlet gas up to 393.15 K. Moreover, a correlation was established between the protective gas inlet velocity and the porosity of porous media. The temperature difference decreased with the increase in the porosity of the inner cavity of the reactor. In contrast to the front and back parts of the inner cavity of the reactor, higher temperature distribution could be obtained in the porous region by increasing the average cell diameters of porous media.