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Distribution of combustible gas alarm based on embedded Ethernet technology
One kind of combustible gas alarms based on industrial Ethernet was designed to prevent the gas leakage in industrial production sites. The alarm adopted the high performance microprocessor LPC2214 as the main chip. The embedded operating system μC/OS-Ⅱ and TCP/IP protocol stack ulP running on LPC2214 con-stitute a development platform of application of the combustible gas alarm. The test shows that it can automati-cally and continuously detect combustible gas in industrial production sites in several positions;it can give out sound-light alarm and take protective measures immediately against the gas leakage ; and it can send the detected data to PC through the Etheruet interface to realize the remote detection. The designed project provides a refer-ence to design industrial devices based on industrial Ethernet....
2020-09-15 12:28:59浏览：35
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The distribution of phenylalkanes in the modern sediment associated with gas hydrate from the Gulf o
Phenylalkanes with carbon numbers between 16 and 19,characterized by the main carbon-18,have been identified in the mod-em sediments collected from gas hydrate area from the Gulf of Mexico.The structure of phenylalkanes with four isomers for ever-y carbon number was determined by means of their mass spectra and previous studies.The distribution of the series character-ized by a low molecular mass was similar to the distribution of n-alkane,alkylcyclohexanes and alkylbenzenes in each sample.There were differences in the distribution of the phenylalkane series between the S - 1,S - 4,S - 7,S - 9 samples and the S -8,S - 10 and S - 11 samples.The phenylalkanes might be derived from Archaea associated with anaerobic oxidation of methane (AOM) processes in S - 1,S - 4,S - 7 and S - 9 samples according to their distribution resembled with the distribution of the extract from a type of Archaea.The distribution of alkylcyclobexanes and alkylbenzenes in S - 1,S - 4,S - 7 and S - 9 sample was found to be similar to each other.The odd-over-even predominance of alkylcyclohexanes was seen as the input of some bac-terial....
2020-09-15 12:28:59浏览：29
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EXPERIMENTAL STUDY OF HFC-134a GAS HYDRATE FORMATION PROCESS
Refrigerant gas hydrates have brilliant prospects as cool storage material of air-conditioning system. In this paper, when the ratio of the weight of HFC-134a to that of water is 2. 17%, systematic experiments have been carried out on the formation process of the HFC-134a gas hydrate including of the phase equilibrium, the influence of supercooling degree, and the influence of agitation. The results indicate that the critical decomposition temperature and the critical decomposition pressure of R134a hydrate is 283.4K and 414K respectively, the formation of gas hydrate was promoted with increasing the supercooling degree and the agitation. However, it is desired that the supercooling degree is smaller.Therefore, it is important problem that the study of optimum of supercooling degree for cool storage system....
2020-09-15 12:28:59浏览：65
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Kinetics of hydrate formation using gas bubble suspended in water
An innovative experimental technique, which was devised to study the effects of temperature and pressure on the rate of hydrate formation at the surface of a gas bubble suspended in a stagnant water phase, was adapted in this work. Under such conditions, the hydrate-growth process is free from dynamic mass transfer factors. The rate of hydrate formation of methane and carbon dioxide has been systematically studied. The measured hydrate-growth data were correlated by using the molar Gibbs free energy as driving force. In the course of the experiments, some interesting surface phenomena were observed....
2020-09-15 12:28:59浏览：76
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Research on the Control Strategy of Variable Nozzle Turbocharger for Natural Gas Engine
A variable nozzle turbocharger (VNT) was applied to a 2.2-liter L4 natural gas engine, and a VNT control system was designed to operate it. Based on VNT matching test results, a VNT control strategy was studied, in which VNT adjustment is carried out through pre-calibrated VNT handling rod position, combined with a closed-loop target boost pressure feedback using proportional-integral-derivative(PID) algorithm. Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT, increase engine volumetric efficiency over a wide speed range, improve engine dynamic characteristics and upgrade economic performance....
2020-09-15 12:28:59浏览：70
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Petroleum geological characteristics of Kela-2 gas field
The Kela-2 gas field is located in the center of Kelasu structural belt in Kuqa Depression. This trap is one of a series of traps in the folded belts which are distributed in a string of pearls in the dual structure. The primary gas- bearing layers are sandstone of Lower Cretaceous K1bs while the secondary layers are dolomite member and glutenite member of Lower Tertiary E1-2km and sandstone of Lower Cretaceous K1b. The main component of natural gas is methane whose content is higher than 97%. It is characterized by dry gas whose source rock is Jurassic coal measure. The Kela-2 structural trap was formed during the Xiyu period and then became a reservoir in the late time. The reservoir formed late and the thick seal rock of Lower Tertiary gipsmantle are the avail reason why the giant Kela-2 gas field has been well kept. The abnormal high pressure of the Kela-2 gas field results from the strong structural compression in the northern part during the Xiyu period....
2020-09-15 12:28:59浏览：28
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Influence of the Feed Gas Composition on the Fischer-Tropsch Synthesis in Commercial Operations
Key technical challenges relating to the Fischer-Tropsch (F-T) synthesis applied in the commercialization of coal/gas-to-liquids (CTL/GTL) technologies have been reviewed. Based on the experiences accumulated from pilot plant, semi-work test and lab researches, the influences of the H2/CO ratio and the CO2 in the feed gas on the F-T process as well as on CTL/GTL complex in terms of product yields, energy efficiency and carbon utilization efficiency have been studied. Being contrary to the current design schemes for F-T process using the coal derived syngas and the iron-based catalyst, it is suggested to feed the F-T synthesis unit with a syngas having a H2/CO ratio of 0.5 and then adjusting to 1.4 via the recycling process. As a result, the carbon efficiency of the whole plant could be reached to as high as 50%. For the issue of CO2 addition to the feed gas, it is proved that only a diluting role is played under the current commercial slurry phase F-T process....
2020-09-15 12:28:59浏览：61
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Gas chromatographic method for the determination of hexaconazole residues in black tea
A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues....
2020-09-15 12:28:59浏览：28
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Power optimization of gas pipelines via an improved particle swarm optimization algorithm
In past decades dynamic programming,genetic algorithms,ant colony optimization algorithms and some gradient algorithms have been applied to power optimization of gas pipelines.In this paper a power optimization model for gas pipelines is developed and an improved particle swarm optimization algorithm is applied.Based on the testing of the parameters involved in the algorithm which need to be defined artificially,the values of these parameters have been recommended which can make the algorithm reach efficiently the approximate optimum solution with required accuracy.Some examples have shown that the relative error of the particle swarm optimization over ant colony optimization and dynamic programming is less than 1％ and the computation time is much less than that of ant colony optimization and dynamic programming....
2020-09-15 12:28:59浏览：57
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Influence of melt superheat on breakup process of close-coupled gas atomization
In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties,and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased from 250 K to 300 K,leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced.However, the log-normal distribution feature of particle size has not been substantially improved....
2020-09-15 12:28:59浏览：39
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GAS分析及其移植的实现
GAS(GNU Assembler)是自由软件基金会的GNU工程的一个开放源代码的汇编器,它目前支持多种目标处理器和多种目标文件格式.本文通过对GAS进行分析,重点研究对其进行移植需要进行的工作.然后根据我们面对的目标处理器的特点和要求,对GAS进行了具体的移植工作,说明了移植的步骤和难点等.该工作成果已经成功地应用到该处理器的研制工作中....
2020-09-15 12:28:59浏览：21
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Characteristics of fracture development and gas extraction of a lower protected seam
To ensure the mining safety of working face in the protective seam and meanwhile extract pressure-relief gas of the lower protected seam and eliminate its outburst risk, the present study researched into fracture development of floor coal-rock mass of the protective seam and migration rule of pressure-relief gas from a protected seam so as to obtain an effective pressure-relief gas extraction method. The results show that after the upper protective seam was mined, mining-induced fracturing floor coal-rock mass fell into two zones: a floor heave fracture zone and a floor heave deformation zone. Lower protected seams located at different fracture subzones were different in the degree and characteristics of fracture development, and penetration borehole drilling from the floor roadway effectively extracted pressure-relief gas. The engineering practice of the Hongling coal mine in Shenyang indicated that for a lower protected seam in the floor heave fracture zone, taking the one time seam spacing (16 m) as the spacing between penetration boreholes ensured the mining safety of the No.321 working face in the protective seam and completely eliminated the outburst risk of the lower protected seam, the No. 12 coal seam....
2020-09-15 12:28:59浏览：70
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Progress in catalytic membrane reactors for removing sulfur from natural gas
Increasingly high requirement driven by environmental concern leads to more rigorous standards for sulfur dosage in fuel. Natural gas desulfurization is an important unit for industrial natural gas process. Catalytic membrane reactor for sulfur compounds removal is a newly emerged and integrated membrane technology. We reviewed the current progress for desulfurization of natural gas with membrane process, and predicted that the process combined with catalytic membrane reactor and microwave irradiation for desulfurization of natural gas might be an integrated and promising unit for large scale desulfurization with high efficiency....
2020-09-15 12:28:59浏览：57
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Destruction mechanism of gas explosion to ventilation facilities and automatic recovery technology
In order to overcome the heavy casualties caused by gas explosion,we verified the propagation law of shock wave in pipeline and the overpressure distribution of gas explosion by similar experiments according to the analyses of reasons for casualty and ventilation system model destroyed by gas explosion in the mining face.We summarized the gas composition after the explosion and its danger,analyzed the effects of the gas explosion shock wave to ventilation system and facilities and the laws of toxic gas spread and diffusion in the ventilation network after the explosion.We presented a technical proposal to control the smoke and recover the ventilation system after a gas explosion and developed a reserve air door and control system that were embed in the lane,and could close automatically in conditions of no pressure and electricity.The results showed that the reserve air door normally opened and could close automatically controlling the smoke flow and resuming the ventilation system when the gas explosion shock wave destroyed the original shutting air door which resulted in the air short circuit....
2020-09-15 12:28:59浏览：45
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Synthesis, Characterization and Evaluation of Sulfur Transfer Catalysts for FCC Flue Gas
In this work, Zr-M (M=Cu, Mn, Ce) type sulfur transfer agent was prepared by impregnation method. Under the condition similar to that in the regenerator of FCC units, the inlfuence of different active metal components and their con-tents on sulfur transfer agent were investigated. Moreover, the crystalline structure of sulfur transfer agent was characterized by X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FT-IR). The result showed that the Zr-Mn sulfur transfer agent could effectively reduce the SO2 content in FCC regenerator lfue gas, featuring high SO2 adsorption capacity. The sulfur transfer agent was inactivated in 40-60 min during the test. In the course of reduction reaction, after several re-action cycles, the formation of SO2 ceased and only H2S was detected as the reduction product....
2020-09-15 12:28:59浏览：60
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