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Supercritical gasification for the treatment of o-cresol wastewater
The supercritical water gasification of phenolic wastewater without oxidant was performed to degrade pollutants and produce hydrogen-enriched gases. The simulated o-cresol wastewater was gasified at 440-650℃ and 27.6 MPa in a continuous Inconel 625 reactor with the residence time of 0.42-1.25 min. The influence of the reaction temperature, residence time, pressure,catalyst, oxidant and the pollutant concentration on the gasification efficiency was investigated. Higher temperature and longer residence time enhanced the o-cresol gasification. The TOC removal rate and hydrogen gasification rate were 90.6% and 194.6%,respectively, at the temperature of 650℃ and the residence time of 0.83 min. The product gas was mainly composed of H2, CO2, CH4 and CO, among which the total molar percentage of H2 and CH4 was higher than 50%. The gasification efficiency decreased with the pollutant concentration increasing. Both the catalyst and oxidant could accelerate the hydrocarbon gasification at a lower reaction temperature, in which the catalyst promoted H2 production and the oxidant enhanced CO2 generation. The intermediates of liquid effluents were analyzed and phenol was found to be the main composition. The results indicate that the supercritical gasification is a promising way for the treatment of hazardous organic wastewater....
2020-09-25 09:10:57浏览：60
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Hydrogen generation from polyvinyl alcohol-contaminated wastewater by a process of supercritical wat
Gasification of polyvinyl alcohol (PVA)-contaminated wastewater in supercritical water (SCW) was investigated in a continuous flow reactor at 723-873 K, 20-36 MPa and residence time of 20-60 s. The gas and liquid products were analyzed by GC/TCD, TOC analyzer and GC/MS. The main gas products were H2, CH4, CO and CO2. Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency, and lower temperature favored the production of H2. The effects of KOH catalyst on gas product composition were studied, and gasification efficiency were analyzed. The TOC removal efficiency (TOCR), carbon gasification ratio (CGR) and hydrogen gasification ratio (HGR) were up to 96.00%, 95.92% and 126.40% at 873 K and 60 s, respectively, which suggests PVA can be completely gasified in SCW. The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment of PVA wastewater....
2020-09-25 09:10:57浏览：43
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多巴胺在污水处理中的应用与展望
主要探讨了多巴胺在污水处理中的优势、自聚-附着机理及其在膜技术和吸附方面的应用以及前景展望,并对目前的研究热点——多巴胺与石墨烯复合材料在水处理中的优缺点与应用现状进行了比较,指出多巴胺在污水处理方面具有良好的应用前景....
2020-09-25 09:10:57浏览：36
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生物膜法处理校区污水
利用两种生物膜技术处理高校生活污水进行了试验研究,结果表明,接触氧化法优于生物转盘法;在停留时间为4h,接触氧化法对CODCr和NH3-N的去除率分别为78.5%和75.6%,出水能达到《城市污水再生利用城市杂用水水质（》GB/T18920-2002）标准;随着气水比的增大,CODCr、NH3-N的去除率先增大后减小,其适宜的气水比为15∶1;出水CODCr浓度随CODCr容积负荷的增大而升高,合理的CODCr容积负荷为6～8kgCODCr/（m3.d）....
2020-09-25 09:10:57浏览：43
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动力煤选煤厂选煤工艺现状及展望
为建立先进、高效、大型化的动力煤选煤厂,分析了动力煤分选的特点,论述了入料原煤不同粒度下的动力煤选煤工艺优缺点及应用情况,并对动力煤选煤工艺进行展望.动力煤分选具有产品结构多元化;以提高精煤发热量,排除矸石及杂物为目的;对产品水分的要求严格;分选盈利性较差等特点.采用50 mm以上块煤和末煤分级入选,减少细粒原煤及系统煤泥入选量,特别减少＜3 mm入选量,可实现动力煤选煤厂精煤产率最大化.开发先进、高效、大型化、低能耗的煤泥水处理工艺及设备;研究高效率、细粒径的干法深度筛分设备,提高筛分效率;开发高效的浓缩分级浮选工艺和设备是动力煤选煤厂的发展趋势....
2020-09-18 16:34:07浏览：26
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New evidence for the origin of natural gas in Ordos Basin from hydrocarbons of oil water
The chief aim of the present work is to investigate the controversy origin of natural gas in the Ordos Basin by using the hydrocarbons of oil water. New evidence has been found: There is relatively high content of light hydrocarbons and low content of heavy components in the hydrocarbons fraction of oil water in the middle gas field of the Majiagou Formation, Ordovician reservoir. The hydrocarbons of oil water in Well Shan 12 and Well Shan 78 have relatively high abundance of tricyclic terpane. Tricyclic terpane/hopane of the two samples are 1.48 and 0.36, respectively. They also show that pregnane and hompregnane are in relatively high abundance with lower hopane/sterane ratio. Pr/Ph is less than 2.0. These characteristics reflected the source input of marine carbonate sedimentary environment. In contrast, the hydrocarbon of Well Shan 81 is lack of tricyclic terpane series and pregnane. It has a high hopane/sterane ratio and Pr/Ph is 3.27. These parameters are typical character of terrestrial organic matter. Furthermore, the hydrocarbons of oil water in Well Shan 37 and Well Shan 34 is between the two typical situations. They have little content of tricyclic terpanes. They may be derived from a mixing source of marine carbonate and terrestrial organic matter input. Similarly, the maturity parameters approve this suggestion. The samples of Well Shan 12 and Well Shan 78 which derived from marine carbonate have relatively high maturity and samples derived from terrestrial organic matter have lower maturity. The maturity of the hydrocarbons of mixing source is between these two situations. The suggestion coincides with the geological background and source rocks distribution....
2020-09-15 12:28:59浏览：50
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Synthesis of Dimethyl Ether from CO Hydrogenation: a Thermodynamic Analysis of the Influence of Wate
Three reactions involved in dimethyl ether (DME) synthesis from CO hydrogenation: methanol synthesis reaction (MSR), methanol dehydration reaction (MDR) and water gas shift reaction (WGSR) are studied by thermodynamic calculation. For demonstrating this process in detail, three models, MSR,MSR+MDR, MSR+MDR+WGSR, are used. Their basic characteristics can be obtained by varying widely the ratios of H2 to CO in the feed (no CO2). Through thermodynamic analysis a chemical synergic effect obviously exists in the second and third models. By comparison between two models it is found that WGSR plays a special role in dimethyl ether synthesis. It is possible for the two models to shift one to the other by regulating CO2 concentration in feed. For Model 2, the selectivity for DME in oxygenates (DME+methanol) does not change with the ratio of H2 to CO....
2020-09-15 12:28:59浏览：42
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Removal of adhesive dusts from flue gas using corona discharges with spraying water
Effective removal of adhesive and fine dusts from flue gas is very difficult. A new method of electrostatic precipitation of the coronadischarges with spraying water(CDSW) was introduced. A new electrode configuration and the circulation spraying of water were employed inthe method. The efficient electrostatic precipitation for adhesive and fine dusts can be accomplished without any drain water during a longoperating period. The fundamental structure, discharge characteristics, mechanism of spraying and precipitation principle of the electrostaticprecipitation using CDSW were described and analyzed. The V-I characteristics, spraying state, supplying water quantity, influence oftemperature and clean of the electrodes were researched in series experiments. The treating effects of circulating spraying using the coronaplasma at the same time of electrostatic precipitation were investigated. The fundamental theories and experimental data were proposed, in orderto effectively remove the adhesive dusts from flue gas using CDSW in practice....
2020-09-15 12:28:59浏览：72
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Characteristics of gas-liquid pulsed discharge plasma reactor and dye decoloration efficiency
The pulsed high-voltage discharge is a new advanced oxidation technology for water treatment.Methyl Orange (MO) dye wastewater was chosen as the target object.Some investigations were conducted on MO decoloration including the discharge characteristics of the multi-needle reactor,parameter optimization,and the degradation mechanism.The following results were obtained.The color group of the azo dye MO was effectively decomposed by water surface plasma.The decoloration rate was promoted with the increase of treatment time,peak voltage,and pulse frequency.When the initial conductivity was 1700 tS/cm,the decoloration rate was the highest.The optimum distahce between the needle electrodes and the water surface was 1 mm,the distance between the grounding electrode and the water surface was 28 mm,and the number of needle electrodes and spacing between needles were 24 and 7.5 mm,respectively.The decoloration rate of MO was affected by the gas in the reactor and varied in the order oxygen ＞ air＞ argon ＞ nitrogen,and the energy yield obtained in this investigation was 0.45 g/kWh....
2020-09-15 12:28:59浏览：73
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Experimental study of water curtain performance for gas storage in an underground cavern
An artificial water curtain system is composed of a network of underground galleries and horizontal boreholes drilled from these galleries. Pre-grouting measures are introduced to keep the bedrock saturated all the time. This system is deployed over an artificial or natural underground cavern used for the storage of gas (or some other fluids) to prevent the gas from escaping through leakage paths in the rock mass. An experimental physical modeling system has been constructed to evaluate the performance of artificial water curtain systems under various conditions. These conditions include different spacings of caverns and cavern radii located below the natural groundwater level. The principles of the experiment, devices, design of the physical model, calculation of gas leakage, and evaluation of the critical gas pressure are presented in this paper. Experimental result shows that gas leakage is strongly affected by the spacing of water curtain boreholes, the critical gas pressure, and the number and proximity of storage caverns. The hydraulic connection between boreholes is observed to vary with depth or location, which suggests that the distribution of water-conducting joint sets along the boreholes is also variable. When designing the drainage system for a cavern, drainage holes should be orientated to maximize the frequency at which they encounter major joint sets and permeable intervals studying in order to maintain the seal on the cavern through water pressure. Our experimental results provide a significant contribution to the theoretical controls on water curtains, and they can be used to guide the design and construction of practical storage caverns....
2020-09-15 12:28:59浏览：65
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Physical Simulation of Water Dissolved Gas (WDG)During Migration
By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as Δ13c,Δd,and Ic4/Nc4 in water-dissolved gas (WDG) during migration) was performed. The result shows that, with the increase of distance, 1) the relative abundance of non-hydrocarbon (CO2) and hydrocarbon (CH4) increase while the relative abundance of hydrocarbon (C2+) decreases (the relative abundance of hydrocarbon (C5+) can be basically negligible); 2) the relative abundance of benzene and methylbenzene increase in the initial time and then decrease. The carbon and hydrogen isotopes of methane vary slightly, which can be regarded as indicators of gas dissolved in water formation....
2020-09-15 12:28:59浏览：65
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体外合成二水草酸钙及其失水过程的热重分析研究
通过体外矿化合成一水草酸钙（COM）和二水草酸钙（COD）晶体,并用XRD和SEM进行表征。同时同步热重分析研究二水草酸钙失水过程的特点。结果表明：COD首先失去的是配位结合水,随着温度的进一步升高,失去晶格结合水。同时进一步验证该热重分析方法可定量分析COD真实的含水量的。...
2020-09-02 20:01:33浏览：73
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热重分析技术在氧化镁含水率检测中的应用
采用烘箱法和马弗炉法测定氧化镁含水率,工作量大、效率低且误差大.热重分析法可以在程序控制温度条件下快速测定氧化镁含水率,研究了各种因素对热重法测定氧化镁含水率的影响.利用TGA-701型热重分析仪在一定的升温速率、温度和气氛条件下,可一次性获得18个试样的氧化镁自由水率和含水率检测结果.多次试验结果表明:该方法简单、快速、准确且重复性好,10个同批次试样测得的氧化镁自由水率和含水率的相对标准偏差分别为0.62％和2.04％....
2020-08-31 10:42:30浏览：35
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