Methane dehydroaromatization over Mo-modified H-MFI for gas to liquid catalysts

For direct gas to liquid（GTL）,a novel process producing energy sources for methane dehydroaromatization is needed.Supporting MoO3 on H-MFI zeolite shows the high catalytic capacity and a selective activity for dehydroaromatization of methane to benzene at 973 K in a fixed bed reactor.On the other hand,deactivation by coke on the active sites in all the catalysts is formed during the reaction.H2 co-feed suppressed the deactivation,which is probably due to the decrease in coking amount.Mo K-edge X-ray absorption fine structure（XAFS） results showed the formation of dispersed Mo2C species with low crystallinity after dehydroaromatization.Mo LIII-edge XANES（X-ray absorption near-edge structure） indicated the formation of active Mo species including Mo2C and Mo-oxycarbide（MoOxCy）,where the redox state should be independent in the absence/presence of H2.It is concluded that Mo-oxycarbide species act as highly active species,and their stability affected the durable activity in the presence of H2.

Evolution and application of in-seam drilling for gas drainage

The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the risk of gas outburst and lower the concentrations of seam gas in the underground ventilation.The drilling practices have reflected the standards of the times and have evolved with the development of technology and equipment and the needs to provide a safe mining environment underground.Early practice was to adapt equipment from other felds,with rotary drilling being the only form of drilling available.This form of drainage allowed various levels of gas drainage coverage but with changing emphasis,research and development within the coal industry has created specifc equipment,technology and practices to accurately place in-seam boreholes to provide effcient and effective gas drainage.Research into gas content determination established a standard for the process and safe levels for mining operations to continue.Surveying technology improved from the wire-line,single-shot Eastman survey instruments which was time-dependent on borehole depth to electronic instruments located in the drill string which transmitted accurate survey data to the drilling crew without time delays.This allowed improved directional control and increased drilling rates.Directional drilling technology has now been established as the industry standard to provide effective gas drainage drilling.Exploration was identifed as an additional beneft with directional drilling as it has the ability to provide exploration data from long boreholes.The ability of the technology to provide safe and reliable means to investigate the need for inrush protection and water drainage ahead of mining has been established.Directional drilling technology has now been introduced to the Chinese coal industry for gas drainage through a practice of auditing,design,supply,training and ongoing support.Experienced drilling crews can offer site specifc gas drainage drilling services utilising the latest equipment and technology.

Investigation on the application of reformed coke oven gas in direct reduction iron production with a mathematical model

To investigate the application of reformed coke oven gas （COG） in producing the direct reduction iron （DRI）, we simulated a countercurrent gas solid moving bed reactor in which the iron ore pellet was reduced by reformed COG. An ordinary differential equation （ODE） was set based on the unreacted shrinking core model considering both mass and energy balances of the reactor. The concentration and temperature profiles of all species within the reactor were obtained by solving the ODE sys tem. The solid conversion and gas utilization were studied by changing gas flow rate, solid flow rate, reactor length, and the ratio of O/CHa to guide the practical application of COG in DRI production. Model results showed that COG was suitable for the DRI production. In order to meet the requirement of the industrial production, the minimum gas flow rate was set as 130,000 Nm3/h, and the maximum production was 90 t/h. The reactor length and the mole ratio x（O）： x（CH4） were depended on the actual industrial situations.

Applying a new method for direct collection, volume quantification and determination of N_2 emission from water

The emission of N2 is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al.（2013） developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N2 and other gases. By the optimized new method, the recovery rate for N2 was 100.28% on average; the mean coefficient of determination（R2） was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N2 concentration as influenced by sample storage times of 1,2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area（%） in comparison with the averaged relative peak area of each method at 0 day.The indices of the bottle full of water method were the lowest（99.5%–108.5%） compared to the indices of vacuum bag and vacuum vial methods（119%–217%）. Meanwhile, the gas chromatograph determination of other gas components（O2, CH4, and N2O） was also accurate. The new method was an alternative way to investigate N2 released from various kinds of aquatic ecosystems.