China 
Africa 
Explore chapters and articles related to this topic
Preparation and use of Biodiesel in a Continuous Process using Alcohol/Water Mixtures
Published in Jorge M.T.B. Varejão, Biomass, Bioproducts and Biofuels, 2022
Thus, it would be desirable in the preparation of biodiesel to change the use of methanol for ethanol, the main problem being to solve the existence of high water content. Its removal, although possible, will add to the cost, making the final price of biodiesel uncompetitive. Simple distillation is an ineffective process for the purification of ethanol, since it forms an azeotropic mixture with water with a composition of approximately 96/4% (v/v) in ethanol/ water. Physical or chemical methods allow to reduce or even eliminate the water content, such as the use of molecular sieves or the addition of dehydrating substances, such as calcium oxide (CaO). With these treatments the water concentration can be reduced to values below 1%, but with the problems mentioned above. In many cases, even this water concentration is unacceptable for the transesterification reaction, making additional ethanol drying techniques necessary. This would lead to the addition of other steps with energy costs and expenses, to a product that already has a small profit margin. This means that switching from methanol to ethanol is far from an easy process, at least with classic transesterification methods catalyzed by a strong base. Alternative processes compatible with the presence of water are necessary to carry out the esterification and transesterification reactions.
Index, Compressibility, and Strength of Marine Sediments
Published in Ronald C. Chaney, Marine Geology and Geotechnology of the South China Sea and Taiwan Strait, 2020
The clay percentage (<0.002 mm) of a marine soil in the area of the South China Sea in general varies from 35% to 60%, the silt percentage generally varies from 40% to 60%, and the sand percentage is generally less than 10% (Cox, 1970). The water content values range from approximately 60% to 100%. In areas having high organic contents between 2% and 5% the values of water content can be increased from 100% to 150%. The marine clays are highly plastic with liquid limits ranging from 50% to 150%. The corresponding Atterberg limit values generally plot close to the Casagrande A-line, indicating a slight organic content and a classification of CH/OH in the united system. In addition, sediments are largely over-consolidated (IL < 1), Figure 6.3.
Lubrication of Water and Steam Turbines
Published in W. S. Robertson, Lubrication in Practice, 2019
The rate of removal of water by drainage, centrifuge and vapour extraction must always exceed its ingress otherwise wet oil will be returned to the system and result in severe corrosion and malfunctioning of the equipment. A sustained high water content can also lead to bacterial and fungal growth in the system[6]. This can cause filter blocking and formation of deposits. Hardening and failure of white metal bearings[7] is accelerated by the presence of water and electrolytes in the oil. To control the corrosive effects of water in the fluid flow phase, and lessen its effects in the static water phase, an adequate degree of rust-preventing characteristics must be maintained. The rusting characteristics test is often used for this purpose and the oil re-inhibited when it fails to pass the test in the presence of distilled water.
Isolation and characterization of phenanthrene-degrading bacteria from urban soil
Published in Bioremediation Journal, 2023
Garima Sharma, Pooja Gokhale Sinha, Kavita Verma, Deevanshi Walia, Milinda Lahiri, Vartika Mathur
The extraction as well as characterization of metabolites was performed according to Rathour et al. (2018) using gas chromatography-mass spectrometry (GC-MS; Shimadzu QP2010 Plus, Japan). Samples were centrifuged at 8000 rpm for 12 min and the supernatant was divided into two parts. Their pH was adjusted to 2.0 and 12 with 1 M HCl and 0.6 N NaOH for parts 1 and 2, respectively. The two parts were mixed thoroughly and 100 ml of ethyl acetate was added. The samples were kept for 1 h in a shaker incubator at 120 rpm, followed by separation of solvent using a separating funnel. Water content was removed using sodium carbonate anhydrous, followed by drying using a rotary evaporator under vacuum conditions (Heidolph, Schwabach, Germany). The dried extract was then mixed with 1.5 ml of ethyl acetate and transferred to GC vials for analysis. For internal standard, 50 µg/ml analytical grade PHE solution (Tokyo Chemical Industry Co. Ltd., Japan) was prepared in pure ethyl acetate.
Microbial community from arid desert oilfield in response to accurate bio-stimulation remediation
Published in Petroleum Science and Technology, 2019
Wenhe Yu, Hongkun Chen, Jiayu Song, Chaocheng Zhao, Xianyuan Du, Chunsheng Guo, Quanwei Song
All DOWRs’ samples were collected from arid desert oilfield in China. Soil chemical properties of 9 soil samples are listed in Table 1. Samples were measured by standard gravimetric techniques to determine water content (Bowles 1992). Oil content was detected using Ultrasonic-Soxhlet extraction gravimetric method (Liang et al. 2011). Soil pH was tested using Seven2Go proTM. Metals were determined using ICP-OES following digestion with a mixture of HNO3/HClO4. Soil samples were dried off and sieved through 150 μm filters to measure soil total phosphorus. Analyses of C%, N%, and C/N in soil were determined by Elementar Vario Macro. Among 9 samples, four major sources of pollution were OS, DS, DC, and AHFW; C_1, C_2, and C_3 were sampled from 3 different uncontaminated points. Each sample was a mixture of five soil cores (0–15 cm) beneath the surface.
Double emulsion oil-in water-in oil (O/W/O) stabilized by sodium caseinate and k-carrageenan
Published in Journal of Dispersion Science and Technology, 2018
Tung Thanh Diep, Thoai Phan Dao, Hien T. Vu, Bao Quoc Phan, Duy Ngoc Dao, Tai Huu Bui, Vinh Truong, Viet Nguyen
Oscillatory analysis results of double emulsions were displayed in Figure 4. The storage modulus of samples was determined in the linear viscous region. It can be seen that the firmness of double emulsions had an increase tendency to the water content. This is quite logic since the repulsion between water droplets contributed to the total mechanical resistance of samples. By applying O/W/O double emulsions in producing fat based products such as margarine, the firmness of products can be increased without adding more solid fat. However, higher water content can affect the stability of product during storage. The increase of water content can lead to the formation of pure water droplets instead of O/W emulsion-droplets. The density discrepancy between those droplets can lead to the coalescence between pure water droplets resulting in a reduction of double emulsions stability.