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Vacuum Filtration
Published in Saravanamuthu Vigneswaran, Roger Ben Aim, Water, Wastewater, and Sludge Filtration, 2020
Vacuum filters have been used in wastewater treatment for dewatering of sludges for more than half a century. A vacuum filter is a cylindrical rotating drum covered with a filter medium, a portion of the circumference being submerged in the sludge to be filtered, and water is drawn through the filter medium by an applied internal vacuum. The main purpose of vacuum filtration is to reduce the sludge volume significantly by dewatering in order to facilitate the subsequent sludge treatment or disposal.
Advances in Algae Dewatering Technologies
Published in Shusheng Pang, Sankar Bhattacharya, Junjie Yan, Drying of Biomass, Biosolids, and Coal, 2019
K.Y. Show, Yuegen Yan, D.J. Lee
The driving power for vacuum filtration is derived from the suction force applied on the filtrate side across the filter medium. In theory, the pressure drop for vacuum filtration is 100 kPa, but the drop was limited to 70 or 80 kPa in practical operations (Shelef et al., 1984). If large algal particles are predominant in the feed, vacuum filtration could generate a harvested product with solids content as good as that of pressure filtration but at lower operating cost.
Equipment and techniques used for obtaining ground water samples
Published in Neal Wilson, Soil Water and Ground Water Sampling, 2020
For purposes of historical review or for ongoing field filtering, a discussion on filtering techniques is warranted. Three main types of filtration apparatus have been used in the field: in-line filtration, positive pressure filtration, and vacuum filtration devices (Figure 5.12). In-line filtration devices include one-use disposable cartridges and holders which house disposable filters.
Production of crude bio-oil and biochar from hydrothermal conversion of jujube stones with metal carbonates
Published in Biofuels, 2018
Gamze Nur Aykaç, Kubilay Tekin, Mehmet Kuddusi Akalın, Selhan Karagöz, Madapusi Palavedu Srinivasan
Hydrothermal conversion experiments were performed in a 500-mL Parr autoclave which is made of stainless steel (Parr 4848 High Temperature and Pressure Reactor). The maximum operating temperature and pressure of the autoclave are 500°C and 35 MPa, respectively. The conversion experiments were carried out at different conditions (i.e. temperatures, residence times and presence of metal carbonate catalysts). In a typical experiment, 8.0 g (dry basis) of granulated jujube stones and 100 mL of deionized water were placed into the reactor. For catalytic runs, an additional metal carbonate (K2CO3, Na2CO3 or SrCO3) in different amounts (0.4, 0.8 and 1.6 g) was added along with the jujube stones. The reactor was then pressurized with nitrogen to remove the air inside. The initial pressure of nitrogen was 2 MPa for each run. The reactor was heated to the desired temperature with an external fabric mantle and the temperature was controlled by a proportional integral derivative module. The stirring speed during the process was 25 rpm for each run. After each experiment, the reactor was cooled to room temperature with the help of an internal stainless steel water cooling coil. Subsequently, the slurry containing liquid and solid products was taken into a flask and the autoclave was then rinsed with water. Acidification of the slurry with hydrochloric acid (1.0 M HCl) was carried out to obtain a pH of approximately 1 [28,29]. Vacuum filtration was carried out for the separation of liquids from solids. The remaining solid (biochar) on the filter paper was dried at 105°C for 2 h. To obtain bio-oil, CH2Cl2 extraction was applied to the liquid phase. The organic phase was isolated and dried with anhydrous Na2SO4. After removing the solvent (dichloromethane), the bio-oil fraction was obtained and quantified using Equation (1). The pH of the bio-oil is acidic, in the range of 3–4. A brief scheme of procedures for separation and extraction after hydrothermal processing is shown in Figure 1.