Temperature adjustment, pretreatment

Physical pretreatment also has an important role to play not just to improve the performance of filters in general but in the case of vacuum filters it may even decide whether or not a vacuum filter can be used at all. Without such pre-treatment, a generally more expensive pressure filter may have to be used. Pretreatment may include crystallization, freezing, temperature adjustment, thermal treatment or ageing, but the three main methods used with vacuum filters are ... 

If poUed, most aquaculturists would probably indicate a preference for well water. Both freshwater and saline wells are common sources of water for aquaculture. The most commonly used pretreatments of well water include temperature alteration (either heating or cooling) aeration to add oxygen or to remove or oxidize such substances as carbon dioxide, hydrogen sulfide, and iron and increasing salinity (in mariculture systems). Pretreatment may also include adjusting pH, hardness, and alkalinity through the appHcation of appropriate chemicals. 

Pretreatment of Suspensions. Another important aspect of soHd—Hquid separation is conditioning or pretreatment of the feed suspension to alter some important property of the suspension and improve the performance of a separator that follows. A conditioning effect is obtained using several processes such as coagulation and docculation, addition of inert filter aids, crystalliza tion, freezing, temperature or pH adjustment, thermal treatment, and aging. The first two operations are considered in more detail due to their importance and wide use. 

Pretreatment of the raw waste gas to remove particulates, adjust temperature and humidify to saturation. 

Table 5 shows HDS product distributions over several catalysts prepared by using the molybdenum-nickel cluster 2. Sulfur content in decane was adjusted to 5.0 wt% in these experiments. MoNi/NaY was found to be more active than MoNi/Al203. It is to be noted that during the high temperature pretreatment the original cluster structure would have been changed. However, the high activity of the MoNi/NaY catalyst for benzothiophene HDS is probably due to the formation of active sites derived from this particular mixed metal cluster. 

Recovery Pretreatment of fermentation broth Adjustment of temperature, pH, ionic strength, addition of flocculation agents... 

Sensitivity analyses were conducted to address the question of whether there is an optimum pretreatment condition that could be used for carbonic acid pretreatment. Laboratory results from Yourchisin and van Walsum (7) and McWilliams and van Walsum (6) indicate that optimal reaction severity would be in the range of Log(R ) = 4.2, where the severity R0 is as defined by Overend and Chornet (10). Relatively high temperature (220°C) and short retention time (4 min) were chosen to achieve this severity, since reactor costs dominate the economics and longer retention times would increase capital costs significantly. Pretreatment temperatures and pressures were varied for this study to determine the sensitivity of the cost to adjustments in these parameters. 

The Frank and Demint [200] method is directly applicable to water samples. After addition of sodium chloride (340g IT1) and aqueous hydrochloric acid (1 1) to bring the pH to 1, the sample was extracted with ethyl ether and the organic layer was then extracted with 0.1M sodium bicarbonate (saturated with sodium chloride and adjusted with sodium hydroxide to pH8). The aqueous solution adjusted to pHl with hydrochloric acid was extracted with ether and after evaporation of the ether to a small volume, Dalapon was esterified at room temperature by addition of diazomethane (0.5% solution in ether) and then applied to a stainless steel column (1.5m/3mm) packed with Chromosorb P (60-80 mesh) pretreated with hexamethyldisilazane and then coated with 10% FFAP. The column was operated at 140°C, with nitrogen carrier gas (30mL muT1) and electron capture detection. The recovery of Dalapon ranged from 91 to 100% the limit of detection was O.lng. Herbicides of the phenoxyacetic acid type did not interfere trichloroacetic acid could be determined simultaneously with Dalapon. 

Adjust the suspension to give a density of 1 x 106 cells/mL. Pipet 100 pL of the cell suspension (1 x 105 cells) (see Note 1) into wells of round- or cone-bottomed 96 multiwell plates that had been pretreated with 200 pL/well of ELISA buffer for 1 h at room temperature. 

The catalysts used in our study were evaluated in a stainless steel tubular reactor (0.25 in external diameter). The catalyst (ca. 0.2 gram) was pretreated with 1% H2/N2 (flow rate 10 ml/min) for 1 h at 250°C imder atmospheric pressure. Then syngas (CO/H2/N2=47.5/47.5/5, BOC UK) was introduced to the reactor and the pressure was increased to 25 bar by using a back-pressure regulator (TESCOM 26-1700). The temperature of reaction (300 C) was adjusted and maintained with a Cole Parmer eontroller. The gas phase products were analysed using an online gas chromatograph (Varian GC 3800). Concentrations of carbon monoxide, carbon dioxide and nitrogen were analysed... 

---