Advanced Materials Research Vols. 347-353

Abstract: The catalyst of FeS modified K2CO3/MoS2 (ADM) (Fe/ADM) were prepared and tested for higher alcohols (C2+OH) synthesis (HAS) from synthesis gas(syngas, mixture of H2 and CO). The effects of CO pretreatment on Fe/ADM catalyst and the catalytic performance for HAS were investigated. The ability for C2+OH formation was enhanced and the hydrocarbon selectivity was lowered after CO pretreatment. The XPS spectra revealed that the iron carbide species appeared and the potassium enriched on the surface of CO pretreated Fe/ADM catalyst, which might be responsible for the high activity of higher alcohols and low hydrocarbons synthesis, respectively.

Abstract: Large LNG storage tanks as liquid natural gas cryogenic pressure vessels, the cold between the tanks and concrete wall is very important. In some special cases, ultra-low temperature liquefied natural gas will enter the second vessel, then the wall will produce thermal stress, at this time the main factor to control the temperature difference between inside and outside the wall is the hot corner protection. This paper introduces the general international structure of tank insulation, and then through the theoretical derivation, gives the insulating layer, hot corner protection and formula for calculating temperature distribution of exterior wall. On this basis, gives the formula for calculating the external thermal stress and thermal protection angle is given control of the thickness of the design equation. Finally, using ADINA finite element software to establish insulation and the wall temperature field model and calculate the heat - wall structure coupled thermal stress, and through the analysis of a project example to verify the correctness of the formula. The results show that in the leakage state, temperature stress of external wall is large, indicating that it is significant to design the thickness of hot corner protection.

Abstract: Biodiesel has become more attractive recently because of its environmental benefits, and the fact that it is derived from renewable resources. Recently, the acidic oil and waste cooking oil were the main resources for the biodiesel production, due to the economical and environmental consideration. However, the product obtained from the transesterification with dark colour. Activated carbon (ACN), activated clay (ACY), activated bleaching earth (ABE), attapulgite (ATE) were employed to refine the undecolored biodiesel. Among all studied decolorants, activated clay exhibited higher activity and more economically competitive. In addition, decoloring process of undecolored biodiesel by activated clay was performed; the optimum conditions were obtained as decoloring temperature 60°C, time 60 min and dosage of activated clay 3 wt. % at atmospheric pressure. Besides, the water content of biodiesel should be below 1 wt. % while ACY was used as decolorant. This paper compared contents and features of decolorization by ACY and rectification under vacuum. The results indicated that higher decolorization ratio(DR) and better quality product will be achieved through rectification, while the decolorization by ACY method should be an proper choice if the biodiesel solded by mixing with diesel fuel.

Abstract: The effect of the calcination temperature on the catalyst performance of ZrO₂-supported cobalt for Fischer-Tropsch synthesis is investigated. Results show that the size of the cobalt species particles of the ZrO₂-supported cobalt catalysts increases and their reducibility is enhanced with increasing calcination temperature. In addition, the extent of CO linear absorption and bridge absorption peak increases and then decreases with increasing calcination temperature. The results from the Fishcer-Tropsch synthesis show that the CO conversion rate increases and then decreases as the calcination temperature is increased. Catalyst selectivity for C₁ monotonically decreases, whereas that for C₅₊ increases. The changes in the CO conversion rate demonstrate a regularity consistent with the trend of the CO absorption peak extent. Meanwhile, the growth and enhanced reducibility of the cobalt species particles contribute to the generation of heavy hydrocarbons and explain the differences in product selectivity. Therefore, the appropriate calcination temperature facilitates an increase in the CO conversion rate of the ZrO₂-supported cobalt catalysts and results in a better Fischer-Tropsch synthesis product selectivity.

Abstract: An overall analysis of primary challenges on energy security of China is made in the new international environments. The challenges comprise: increasing pressure on energy supply, block effect of greenhouse gases emissions, a good many hazards in the international energy cooperation, renewable energy and desiderating reinforce of energy reserves and pre-warning system. The new strategic thoughts of China’s energy security involving strengthening six abilities are put forward for safeguarding energy security. The six abilities include: supply (multi development), adjustment and command (energy saving priority), emergency capability (contingency reserves), participation (international cooperation), influence (diplomatic operation) and control (military safeguard).

Abstract: As ceramic oxidation bed has high heat transfer efficiency, now, great attention has been given on it. In the oxidation bed, between the honeycomb holes of the fore-and-aft blocks of ceramic honeycombs, there are dislocation relationships. The effect of dislocation relationship on the pressure drop of the oxidation bed was numerically simulated by Fluent software. The results show that, between the two blocks of closely adjacent ceramic honeycombs, when a gap distance of 1mm was left, compared to the situation the gap distance is 0, the overall resistance loss of the oxidation bed reduced vast.

Abstract: Based on the data of GDP and population during the period 2003-2008, the energy demand in 2020 for industrial and residential energy in Dongtan area of Chongming Island was forecasted through the scenario simulation, and together with other research material, the development status of renewable energy was also detected. The results show that: 1) Under the low and high scenarios (LS and HS), the industrial energy demand in 2020 will respectively reach 127944 tce (ton of standard coal equivalent) and 401817 tce, which are 1.9 and 6 times that in 2008, respectively. While the residential energy demand under LS and HS in 2020 differentiates little from each other, and it is about 50% of increment compared with the current consumption. 2) The industrial and residential energy demand in 2020 under the moderate scenario (MS), which is more reasonable to energy prediction, will be respectively 264881 tce and 32.5 million kwh, and with the average annual increase rate of 12.1% and 3.5% from 2008 to 2020, respectively. 3) The development degree of the wind energy and solar energy in Dongtan is currently considerably low, which accounts for less than 1% in the energy structure. the findings suggest that the energy scheduling and planning should be implemented to coordinate the balance between energy demand and energy supply in the future; meanwhile, it is necessary to adjust the energy structure and develope renewable energy such as wind and solar energy in the next decades to address environmental problems resulting from the consumption of a mass of fossil fuels.

Abstract: The Fukushima nuclear accident is prompting countries around the world to reassess the safety of nuclear power plant and their nuclear development aspirations. The course of Fukushima nuclear accident, the accident status to date are summarized, the global support for nuclear energy after Fukushima are stated, and the nuclear power development in China, China responses to Fukushima accident are analyzed. Nuclear energy plays an important role as means to adjust the energy structure, to avoid environmental pollution, and to address climate change in China, while the development speed of nuclear power should be reasonable and appropriate. Drawing lessons from Fukushima crisis, China insists on the safety-first principle in nuclear power development, hence China should be cautions in NPP sites selection, reviews its nuclear power development speed, lifts the safety standards, and improve the nuclear emergency response capabilities.

Abstract: Evaluating underground environmental safety is not an easy task as it involves many variable evaluation indexes which are immeasurable, vague and uncertain. Also, the available information for evaluation may be incomplete due to the difficulty of underground data acquisition and complexity of the influence factors. Considering the different effect of various evaluation indexes on underground environmental safety in different conditions, a dynamical weight algorithm of various indexes is presented. The fuzzy evaluation method with dynamic weight is applied in evaluating underground environmental safety at one of the coal mines in YangQuan coal industry. Findings conclude that the proposed dynamic weight method is better than the traditional method, which gives a promising prospect in underground environmental safety evaluation. And it provides a more reasonable and intelligent evaluation with accurate results.

Abstract: NOx and CO emissions of fuel rich-lean flame of natural gas water heaters were experimentally investigated. Fuel-rich and fuel-lean flame with different air factors were analyzed separately. Emission of fuel-rich flame is CO whereas emission of fuel-lean is NOx, and fuel rich-lean ratio is the most important factor for NOx and CO emission. If fuel-rich flame α1 is changed with constant fuel-lean flame α2, NOx emission decreases and CO emission increases evidently. If α2 is changed with constant α1, NOx decreases slightly and CO increases initially and then decreases. Depressing fuel-lean flame can strengthen excess O2 diffusion to fuel-rich flame, and then reduces NOx and CO emissions.