Catalytic steam reforming of biomass over Ni-based catalysts: Conversion from poplar leaves to hydrogen-rich syngas

A series of Ni/SBA-15 catalysts with Ni contents from 5 wt%–20 wt%and CaO-12.5%Ni/SBA-15 catalysts with CaO contents from 1.4 wt%– 9.8 wt%have been prepared.The structure of the catalysts was characterized using X-ray diffraction（XRD）,N2 adsorption-desorption,transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）.The performance of catalytic steam reforming of the poplar leaves to the hydrogen-rich syngas was tested in a fixed-bed reactor.The results indicate that the 7.0wt%CaO-12.5wt%Ni/SBA-15 catalyst exhibits the best performance for the catalytic steam reforming of poplar leaves to hydrogen-rich syngas.The ratio of H2：CO can reach ca 5：1 in the hydrogen-rich syngas.The yield of H2 can reach 273.30 mL/g（poplar leaves）.In the CaO-Ni/SBA-15 catalyst,Ni active component mainly fills the role of catalytic steam reforming of the poplar leaves,and CaO active component mainly plays the role as water-gas shift and CO2 sorbent.

Hydrogen production via chemical looping reforming of coke oven gas

Coke oven gas(COG)is one of the most important by-products in steel industry,and the conversion of COG to value-added products has attracted much attention from both economic and environmental views.In this work,we use the chemical looping reforming technology to produce pure H_(2) from COG.A series of La1-xSrxFeO_(3)(x?0,0.2,0.3,0.4,0.5,0.6)perovskite oxides were prepared as oxygen carriers for this purpose.The reduction behaviors of La1-xSrxFeO_(3) perovskite by different reducing gases(H_(2),CO,CH4 and the mixed gases)are investigated to discuss the competition effect of different components in COG for reacting with the oxygen carriers.The results show that reduction temperatures of H_(2) and CO are much lower than that of CH4,and high temperatures(>800℃)are requested for selective oxidation of methane to syngas.The co-existence of CO and H_(2) shows weak effect on the equilibrium of methane conversion at high temperatures,but the oxidation of methane to syngas can inhibit the consumption of CO and H_(2).The doping of suitable amounts of Sr in LaFeO_(3) perovskite(e.g.,La0.5Sr0.5FeO_(3))significantly promotes the activity for selective oxidation of methane to syngas and inhibits the formation of carbon deposition,obtaining both high methane conversion in the COG oxidation step and high hydrogen yield in the water splitting step.The La0.5Sr0.5FeO_(3) shows the highest methane conversion(67.82%),hydrogen yield(3.34 mmol g^(-1))and hydrogen purity(99.85%).The hydrogen yield in water splitting step is treble as high as the hydrogen consumption in reduction step.These results reveal that chemical looping reforming of COG to produce pure H_(2) is feasible,and an O_(2)-assistant chemical looping reforming process can further improves the redox stability of oxygen carrier.

Kinetic model on coke oven gas with steam reforming

The effects of factors such as the molar ratio of H2O to CH4 (n(H2O)/n(CH4)), methane conversion temperature and time on methane conversion rate were investigated to build kinetic model for reforming of coke-oven gas with steam. The results of experiments show that the optimal conditions for methane conversion are that the molar ratio of H2O to CH4 varies from 1.1 to 1.3 and the conversion temperature varies from 1 223 to 1 273 K. The methane conversion rate is more than 95% when the molar ratio of H2O to CH4 is 1.2, the conversion temperature is above 1 223 K and the conversion time is longer than 0.75 s. Kinetic model of methane conversion was proposed. All results demonstrate that the calculated values by the kinetic model accord with the experimental data well, and the error is less than 1.5%.

Steam Reforming of Natural Gas： A Value Addition to Natural Gas Utilization in Nigeria

Petrochemicals play a vital role in the economy of any nation. The products of the industry are the building blocks in many industries as they deepen the forward and backward linkages of the petroleum sector with the rest of the economy. The industry uses a variety of hydrocarbon feedstock such as different cuts of naphtha from refinery and natural gas. One of the problems facing the industry is lack of reliable feedstock supplies. Nigeria has the potential to be a major petrochemicals producer. With proven gas reserves currently estimated at 187 tcf, not much has been accomplished with respect to the effective exploitation and utilization of this resource as most of the nation＇s natural gas production has been flared, liquefied for export or re-injected to enhance greater crude oil recovery. It has become imperative to further find ways to exploit and utilize the nation＇s natural gas reserves and translate it to the improvement of the nation＇s economy. Steam reforming of natural gas is one of the avenues for conversion of natural gas to petrochemicals. This paper, however, reviews various ways of utilizing natural gas, examines the process details of steam reforming of natural gas as a route to optimized natural gas utilization and industrialization in Nigeria. Syngas （synthesis gas） is a versatile feedstock for most petrochemicals and chemical intermediates. Thus utilizing natural gas in this way would strengthen the petrochemical industry making it possible for the country to change from raw materials to value-added products supplier, boost the economy and solve the ＂hydra-headed＂ problem of unemployment in Nigeria with its multiplier employment effect.

Review on Innovative Catalytic Reforming of Natural Gas to Syngas

Decreasing supplies of high quality crude oil and increasing demand for high quality distillates have motivated the interest in converting natural gas to liquid fuels, especially with the present boom in natural gas proven reserves. Nevertheless, one major issue is the curtailment of costs incurred in producing synthesis gas from natural gas, which account for approximately 60% of the costs used in producing liquid fuels. While there are three main routes to convert natural gas to syngas: steam reforming (SMR), partial Oxidation (POX) and auto-thermal reforming (ATR). Significant new developments and improvements in these technologies, established innovative processes to minimize greenhouse gases emission, minimize energy consumption, enhance syngas processes, adjust the desired H2/CO ratio and change the baseline economics. This article reviews the state of the art for the reforming of natural gas to synthesis gas taking into consideration all the new innovations in both processes and catalysis.

Study of a Catalyst for Energy-Saving Natural Gas Steam Reforming

The DS-1 catalyst for energy-saving natural gas steam reforming was preparedby using potash as a carbon-resistant additive and adding rare earth oxide. The catalystdemonstrated good reducibility, carbon resistance, activity and stability in aging tests and 500 hstability tests at low water/carbon ratios.

Steam Reforming of Dimethyl Ether by Gliding Arc Gas Discharge Plasma for Hydrogen Production

Gliding arc gas discharge plasma was used for the generation of hydrogen from steam reforming of dimethyl ether(DME).A systemic procedure was employed to determine the suitable experimental conditions.It was found that DME conversion first increased up to the maximum and then decreased slightly with the increase of added water and air.The increase of total feed gas flow rate resulted in the decrease of DME conversion and hydrogen yield,but hydrogen energy consumption dropped down to the lowest as total feed gas flow rate increased to76 ml·min 1.Larger electrode gap and higher discharge voltage were advantageous.Electrode shape had an important effect on the conversion of DME and production of H2.Among the five electrodes,electrode 2#with valid length of 55 mm and the radian of 34 degrees of the top electrode section was the best option,which enhanced obviously the conversion of DME.

Modeling the kinetics of methane conversion in steam reforming process of coke-oven gas based on experimental data

Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and HE, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from .500 ℃ to 9.50 ℃, and developed a kenetic model for, ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows： the ratio of the amount of water to the amount of methane is from 1.1 to 1.3; the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s.

PEMFC Application in a Gliding Arc Plasam-Catalysis Reforming System using Biogas

In this study, bio-waste gas is converted to sustainable hydrogen energy in good quality and low pollution. In addition, generated highly concentrated hydrogen is applied to fuel cell (PEMFC) to resolve environmental and energy crisis issue via gliding arc plasma system. Parameters that can affect the reforming performance of bio-gas in gliding arc plasma system were studied. Especially, the optimal operating condition in water gas shift reactor and preferential oxidation reactor for CO removal was proposed. For the parametric re-searches, change in steam feed amount and temperature change in catalyst bed in water gas shift reactor were studied. For the preferential oxidation reactor, air input flow rate change and temperature variation in catalyst bed were evaluated. The optimal operating conditions for gliding arc plasma reforming system are proposed as 6:4 of biogas component ratio (i.e., CHR4R:CO), 3 of steam/carbon ratio, 16 L/min of total gas flow rate, and 2.4 kW of input electric power. Where, the concentration of biogas that passed each reactor shows 57.5% of HR2R, 7 ppm of CO, 9.2% of COR2R, and 3.4% of CHR4R. Therefore, less than 10 ppm of CO is achieved, and this system can be applicable for PEMFC.

The Joule–Thomson effect of (CO_(2)+H_(2)) binary system relevant to gas switching reforming with carbon capture and storage(CCS)

The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determine the Joule-Thomson effect of binary mixtures(CO_(2)+ H_(2)). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule-Thomson coefficients(μ_(JT)) for(CO_(2)+ H_(2)) binary mixtures with mole fractions of carbon dioxide(x_(CO_(2))= 0.1, 0.26, 0.5,0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs(PR,SRK, PR, BWR and GERG-2008 equation) were used to calculate the μ_(JT)for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature.Moreover, the Joule-Thomson inversion curves(JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO_(2). The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.

Production of Synthesis Gases from Ethanol Steam Reforming Process

In this study, the production of synthesis gases has been purposed under between 250oC - 700oC and 1 - 2 bars pressures. The research was conducted over a commercial BASF catalyst and a laboratory prepared catalyst. The catalyst has a content of different substances including basically NiO/Al2O3 and some additionals (Ca, Mg, Cr, Si). The experimental measurements were carried out within a recently developed experimental equipment which can be operated up to 1200o and 1 to 3 bars pressures. The study was conducted over a commercial BASF catalyst and a laboratory prepared catalyst under different ethanol/water ratios, temperatures, and catalyst loads. Under the condition when ethanol/water ratios were decreased from 1/2 to 1/10, it was observed that hydrogen ratios increased in exit gas composition of the reactor. With increments in catalyst loads from 1 to 5 grammes, hydrogen ratios in exit gas composition gradually increased. Reaction of ethanol-steam reforming started nearly at 300oC, and when temperature increments continued further up to 700oC, hydrogen yields in exit gas compositions of the reactor increased significantly to a range of 70% - 80%. In the case of using commercial BASF catalyst, hydrogen ratios in exit gas composition were found slightly higher than laboratory prepared catalyst. According to our observations, life time of laboratory prepared catalyst was found higher than the commercial BASF catalyst. In this study which kinetic measurements were applied, some kinetic parameters of ethanol-steam reaction were calculated. The mean activation energy of ethanol consumptions at 573oK - 973oK was found as 26.87 kJ/mol, approximately. All kinetic measurements were analyzed with a first order reaction rate model. In this study, some diffusion limitations existed, however, overall reaction was chemically controlled.

Morphology effect of zirconia support on the catalytic performance of supported Ni catalysts for dry reforming of methane

An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.

Production of hydrogen-rich gas and multi-walled carbon nanotubes from ethanol decomposition over molybdenum modified Ni/MgO catalysts

A series of molybdenum modified Ni/MgO catalysts （Ni-Mo/MgO） with different loading ratios of Ni ： Mo were prepared by impregnation method. Ethanol decomposition to co-produce multi-walled carbon nanotubes and hydrogen-rich gas at temperatures of 600-800 ℃ was inves- tigated over the synthesized Ni-Mo/MgO catalysts. The results showed that the catalytic activity depended strongly on the reaction temperature and loading ratio of Ni ： Mo. According to the gaseous and solid products obtained, the reaction pathways for ethanol decomposition were suggested.

Effect of MgO promoter on Ni-based SBA-15 catalysts for combined steam and carbon dioxide reforming of methane

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.

Comparison of dry reforming of methane in low temperature hybrid plasma-catalytic corona with thermal catalytic reactor over Ni/γ-Al_2O_3

In the current study, the hybrid effect of a corona discharge and γ-alumina supported Ni catalysts in CO2 reforming of methane is investigated. The study includes both purely catalytic operation in the temperature range of 923-1023 K, and hybrid catalytic-plasma operation of DC corona discharge reactor at room temperature and ambient pressure. The effect of feed flow rate, discharge power and Ni/γ-Al2O3 catalysts are studied. When CH4/CO2 ratio in the feed is 1/2, the syngas of low Ha/CO ratio at about 0.56 is obtained, which is a potential feedstock for synthesis of liquid hydrocarbons. Although Ni catalyst is only active above 573 K, presence of Ni catalysts in the cold corona plasma reactor （T≤523 K） shows promising increase in the conversions of methane and carbon dioxide. When Ni catalysts are used in the plasma reaction, H2/CO ratios in the products are slightly modified, selectivity to CO increases whereas fewer by-products such as hydrocarbons and oxygenates are formed.

Photocatalytic dry reforming of methane by rhodium supported monoclinic TiO_(2)-B nanobelts

The conversion of methane and carbon dioxide into syngas(dry reforming of methane;DRM)has attracted attention owing to the potential to reuse greenhouse gases.Titanium dioxide(TiO_(2))-based photocatalysts,which have been widely commercialized owing to their high efficiency,non-toxicity,and low cost,are strongly desired in DRM.Here,we report a monoclinic-phase TiO_(2)-B nanobelts-supported rhodium(Rh/TiO_(2)-B nanobelts)catalyst that efficiently promotes DRM under ultraviolet light irradiation at low temperatures.Photogenerated holes in the TiO_(2)-B nanobelts were used to oxidize methane,while the electrons were trapped in rhodium to reduce carbon dioxide.Rh/TiO_(2)-B nanobelts exhibited considerably higher durability and activity than Rh-loaded conventional TiO_(2)(anatase and rutile),owing to the lattice and/or surface oxygen reactivity in TiO_(2)-B nanobelts,which was suggested by X-ray photoelectron spectroscopy measurements and photocatalytic performance tests under an atmosphere of methane alone.This study paves the path for the effective utilization of methane by constructing active TiO_(2)-based nanometal photocatalysts.

How did the price and income elasticities of natural gas demand in China evolve from 1999 to 2015? The role of natural gas price reform

As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mechanism.Employing a set of unbalanced panel data for China’s 30 provinces covering 1999-2015,this study aims to estimate the evolving price and income elasticities of natural gas demand and explore the effect of natural gas price reform in China.For this purpose,a series of econometric techniques allowing for cross-sectional dependence and slope homogeneity is utilized.The results suggest that although natural gas demand in China still lacks negative price elasticity,the phenomenon is improving.Moreover,the estimates suggest that natural gas demand in China is indeed becoming increasingly sensitive to income changes.Our estimates also provide strong evidence in favor of the effect of natural gas price reform on the change in price elasticity as the price elasticity decreases in five of the seven regions.In addition,the results indicate large variations in the change in price and income elasticities of natural gas demand across China’s regions.Natural gas demand is becoming more price inelastic in Southwest China and Northwest China,while such demand in North China and East China responds less sensitively to income changes.These findings offer several policy suggestions for the reform of China’s natural gas market at the national and regional levels.

CO Selective Oxidation in Hydrogen-Rich Gas over Copper-Series Catalysts

The performances of CO selective oxidation in hydrogen-rich gas over fourcatalytic systems of CuO/ZrO_2, CuO/MnO_2, CuO/CoO and CuO/CeO_2 were compared. The reducibility ofthese catalysts and the effect of CuO and CeO_2 molar ratio of CuO/CeO_2 catalysts on the activityof selective CO oxidation are investigated by XRD and TPR methods. The results show that thecatalysts with the exception of CuO/ZrO_2 have the interactions between CuO and CoO, CeO_2 or MnO_2,which result in a decrease in the reduction temperature. Among the catalysts studied, CuO/ZrO_2catalyst shows the lowest catalytic activity while CuO/CeO_2 catalyst exhibits the best catalyticperformance. The CuO(10%)/CeO_2 catalyst attains the highest CO conversion and selectivity at 140and 160℃. The addition of 9% H_2O in the reactant feed decreases the activity of CuO/CeO_2 catalystbut increases its CO selectivity.

Low-temperature utilization of CO_2 and CH_4 by combining partial oxidation with reforming of methane over Ru-based catalysts

Combination of partial oxidation of methane （POM） with carbon dioxide reforming of methane （CRM） has been studied over Ru-based catalysts at 550℃.POM,CRM and combined reaction were performed over 8wt%Ru/γ-Al2O 3 and the results show that both POM and CRM contribute to the combined reaction,between which POM plays a more important role.Moreover,the addition of Ce to Ru-based catalyst results in an improvement in the activity and CO selectivity under the adopted reaction conditions.The Ce-doped catalyst was characterized by N2 adsorption-desorption,SEM,XRD,TPR,XPS and in situ DRIFTS.The mechanism has been studied by in situ DRIFTS together with the temperature distribution of catalyst bed.The mechanism of the combined reaction is more complicated and it is the combination of POM and CRM mechanisms in nature.The present paper provides a new catalytic system to activate CH4 and CO2 at a rather low temperature.

On the Supply-side Structural Reform in the Oil and Gas Industry

The supply-side structural reform in the oil and gas industry can be divided into three different levels. At present, there are four major categories of problems—a weak supply insurance capacity, a structural supply and demand imbalance, a certain degree of excess capacity and an imperfect market system. The primary target of supply-side reform in the oil and gas industry is ensuring a clean and efficient supply. The focus is to optimize the allocation of resources, improve resource allocation efficiency, and improve total factor productivity. Under the new situation, we should adjust the strategy and tactics used for supply insurance and carry out three tasks. We must adhere to the principles of "marketization", "globalization" and "integration" reform, strengthen the building of supply insurance capacity, improve the oil and gas market system, optimize the industry structure, and resolve excess capacity.