Statistical optimization of operating parameters of microbial electrolysis cell treating dairy industry wastewater using quadratic model to enhance energy generation

The performance of Microbial electrolysis cell (MEC) is affected by several operating conditions. Therefore, in the present study, an optimization study was done to determine the working efficiency of MEC in terms of COD (chemical oxygen demand) removal, hydrogen and current generation. Optimization was carried out using a quadratic mathematical model of response surface methodology (RSM). Thirteen sets of experimental runs were performed to optimize the applied voltage and hydraulic retention time (HRT) of single chambered batch fed MEC operated with dairy industry wastewater. The operating conditions (i.e) an applied voltage of 0.8 V and HRT of 2 days that showed a maximum COD removal response was chosen for further studies. The MEC operated at optimized condition (HRT- 2 days and applied voltage- 0.8 V) showed a COD removal efficiency of 95 ± 2%, hydrogen generation of 32 ± 5 mL/L/d, Power density of 152 mW/cm² and current generation of 19 mA. The results of the study implied that RSM, with its high degree of accuracy can be a reliable tool for optimizing the process of wastewater treatment. Also, dairy industry wastewater can be considered to be a potential source to generate hydrogen and energy through MEC at short HRT.     

Laboratory Studies to Determine Suitable Chemicals to Improve Oil Recovery from Garzan Oil Field

Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated.     

贵州职业技术学院数据中心双活技术架构的研究

The importance of data processing and storage to colleges and universities is increasing day by day. However, many colleg- es and universities are still at a low level in the process of data recovery and application reduction, and its RPO and RTO indicators need to be improved by adopting the dual active technology architecture. Taking the Guizhou Vocational Technology Institute as an example, this paper focuses on the analysis of the architecture of the double active data center, aiming at the actual situation of the college, and gradually realizes multiple disaster recovery level of data level, application level and business level.     

海上稠油油田蒸汽吞吐产量确定新方法

针对目前蒸汽吞吐产量预测模型假设条件简单、普适性差等问题,一般采用测试法和类比法综合确定海上稠油油田蒸汽吞吐初期产量。由于目前海上油田通常只开展常规测试,无法直接获得热采开发初期产量。笔者提出海上稠油油田蒸汽吞吐初期产量确定新方法,建立蒸汽吞吐相对于常规开发的初期产量倍数预测模型,通过蒸汽吞吐产量倍数,将常规测试确定的产量转化为蒸汽吞吐产量。研究表明,蒸汽吞吐初期产量倍数主要受储集层渗透率、原油黏度、注入强度、蒸汽干度等因素影响,利用正交试验设计和多元回归等方法,建立海上稠油油田蒸汽吞吐初期产量倍数与油藏地质参数及注入参数之间的非线性预测模型,该模型经实际生产数据验证,预测误差小于5%,可靠性高,能够为海上稠油油田蒸汽吞吐初期产量的确定提供依据。     

Enhanced oil recovery from carbonate reservoirs by spontaneous imbibition of low salinity water

An experimental study was performed to investigate the impact of low salinity water on wettability alteration in carbonate core samples from southern Iranian reservoirs by spontaneous imbibition. In this paper, the effect of temperature, salinity, permeability and connate water were investigated by comparing the produced hydrocarbon curves. Contact angle measurements were taken to confirm the alteration of surface wettability of porous media. Oil recovery was enhanced by increasing the dilution ratio of sea water, and there existed an optimum dilution ratio at which the highest oil recovery was achieved. In addition, temperature had a very significant impact on oil recovery from carbonate rocks. Furthermore, oil recovery from a spontaneous imbibition process was directly proportional to the permeability of the core samples. The presence of connate water saturation inside the porous media facilitated oil production significantly. Also, the oil recovery from porous media was highly dependent on ion repulsion/attraction activity of the rock surface which directly impacts on the wettability conditions. Finally, the highest ion attraction percentage was measured for sodium while there was no significant change in pH for all experiments.     

AHP FUZZY在残采工程方案优选中的应用

为探讨太白金矿回收原采场边部残余低品位矿体的方案，通过层次分析法（AHP）与模糊数学（FUZZY）理论，选取对残采工程影响较大的9个因素，建立优选模型。运用层次分析法确定了各评价指标的权重；采用模糊数学法分析计算各采矿方法的定性、定量指标，分别得到各评价指标的隶属度。最终计算出3种工程布置方案的综合优选度分别为68.1%、69.3%、58.1%，从而沿矿体走向双进路布置确定为最优开采方案。实践表明，采用该模型优选的工程布置方案具有一定的科学性、合理性，值得借鉴与推广。     

A small-scale silica gel-water adsorption system for domestic air conditioning and water heating by the recovery of solar energy

A small-scale silica gel-water adsorption system with modular adsorber, which utilizes solar energy to achieve the cogeneration of domestic air conditioning and water heating effect, is proposed and investigated in this paper. A heat recovery process between two adsorbers and a mass recovery process between two evaporators are adopted to improve the overall cooling and heating performance. First, the adsorption system is tested under different modes (different mass recovery, heat recovery, and cogeneration time) to determine the optimal operating conditions. Then, the cogeneration performance of domestic cooling and water heating effect is studied at different heat transfer fluid temperatures. The results show that the optimal time for cogeneration, mass recovery, and heat recovery are 600 s, 40 s, and 40 s, respectively. When the inlet temperature of hot water is around 85°C, the largest cooling power and heating power are 8.25 kW and 21.94 kW, respectively. Under the condition of cooling water temperature of 35°C, the obtained maximum COP_c, COP_h, and SCP of the system are 0.59, 1.39, and 184.5 W/kg, respectively.     

A Smart Flexible Solid State Photovoltaic Device with Interfacial Cooling Recovery Feature through Thermoreversible Polymer Gel Electrolyte

Quasi‐solid‐state dye‐sensitized solar cells (DSSCs) fabricated with lightweight flexible substrates have a great potential in wearable electronic devices for in situ powering. However, the poor lifespan of these DSSCs limits their practical application. Strong mechanical stresses involved in practical applications cause breakage of the electrode/electrolyte interface in the DSSCs greatly affecting their performance and lifetime. Here, a mechanically robust, low‐cost, long‐lasting, and environment‐friendly quasi‐solid‐state DSSC using a smart thermoreversible water‐based polymer gel electrolyte with self‐healing characteristics at a low temperature (below 0 °C) is demonstrated. When the performance of the flexible DSSC is hindered by strong mechanical stresses (i.e., from multiple bending/twisting/shrinking actions), a simple cooling treatment can regenerate the electrode/electrolyte interface and recover the performance close to the initial level. A performance recovery as high as 94% is proven possible even after 300 cycles of 90° bending. To the best of our knowledge, this is the first aqueous DSSC device with self‐healing behavior, using a smart thermoreversible polymer gel electrolyte, which provides a new perspective in flexible wearable solid‐state photovoltaic devices.