CBS slurry

When components of CBS slurry dissolve in water, their aqueous ions may have a different ionic size as compared to that in the unreacted crystal, and hence, the volume of the dissolved species may be different from that of the unreacted components. Thus, the total volume after dissolution Vf may be different from the total volume prior to dissolution Vq-This volume change will occur against the downhole pressure, because the slurry components will be mixed during pumping and wiU dissolve when they are placed in downhole conditions. Thus, the change in enthalpy of an individual component is given by... 

If we assume in Eq. 15.6 that the volume change AV does not depend on the temperature and pressure, we can write AVf = AVq, and the last two terms on the right-hand side reduce to (Pf — Pq)AVq. Calculations from this equation, based on the ionic radii of the right-hand side and the molecular radii of the left-hand side (see Ref. [4] for these data) of Eq. 15.3, indicate that AVq is very small even at a high pressure difference (Pf — Pq) Therefore, the pressure effects on the oxide solubility can be ignored, and the only variable one needs to consider while formulating the CBS slurry is the downhole temperature. 

When the CBS slurry is pumped down a borehole and as it travels through the borehole, its temperature will increase with depth. The higher temperature wiU, in turn, increase the solubility of the oxide components in the slurry. If the solubility of the oxides becomes too high, the slurry may flash set within the borehole prematurely and clog it. To avoid this situation and to allow free flow of the slurry, one must control the solubility of the oxides. Alternatively, one may use components that have their maximum solubility only at the... 

To assess the acid-base characteristics of the CBs after chemical treatment, the pH of the CB slurry was determined by a boiling method in accordance with ASTM D1512. The boiling method was performed by placing 5g of the CBs into 50 ml of deionized water contained in a 100 ml beaker. The pH measurement was taken after 2 min equilibrium time. 

Bedard et al. [245] reported that PCB dechlorination was stimulated by adding 2,5,3, 4 -tetrachlorobiphenyl (25-3 4 -CB) to slurries (incubated under methanogenic conditions) of sediments contaminated with Aroclor 1260 from Woods Pond (MA). The 25-3 4 -CB was converted stoichio-metrically to 25 - 3 -CB and stimulated a selective para-dechlorination which decreased the penta- through heptachlorobiphenyls containing 234-, 245-, or 2345-chlorophenyl groups by up to 83% in 12 weeks. 

Purification of CB[5], CB[6], CB[7], CB[8], CB[10] CB[5], and i-CB[6] The reaction mixture, which contained a large amount of solid, was evaporated to a minimum volume ( 600 mL). This slurry was poured into water (2.5 L). The solid was collected by filtration (Crop 1 contains CB[6], CB[7], CB[8], some i-CB[6], and some CB[10] CB[5]). The filtrate was evaporated to about 600 mL and then slowly poured into a mixture of MeOH (3 L) and water (200 mL) with vigorous stirring. After stirring overnight, the precipitate was isolated by filtration (Crop 2 contains mainly CB[7] and CB[5] and smaller amounts of CB[6]). 

Room-temperature compressive strength (psi) 7000-8000 ==4000 Higji strength of CBS allows addition of cenospheres, etc., that improve thermal properties and reduce slurry weight... 

In general, the same compositions used for onshore wells also work for the offshore wells. Saline water retards the setting rate, and longer pumping time is available for the same CBS formulation in offshore wells compared with onshore wells. In addition, because the saline water contains dissolved solids, one needs to add more water in the slurry to obtain the same low initial Be. Results of the pumping time versus temperature are shown in Table 15.6 for formulations that are similar to those given in Table 15.5. 

Price CB, Brannon JM, and Hayes C, Effect of redox potential and pH on TNT transformation in soil-water slurries, J. Environ. Eng., 123, 988,1997. 

Carter CB, Norton MG (2007) Ceramics materials science and engineering. Springer, Berlin Tsetsekou A, Agrafiotis C, Milias A (2001) Optimization of the rheological properties of alumina slurries for ceramic processing appUcations—Part I slip casting. J Eur Ceram Soc 21 363-373... 

In hydroprocessing catalysis, carbon blacks can be used either directly by slurrying with a feed or used for the preparation of CBC that are suitable supports for the catalyst preparation. The properties of some commercial CBs are shown in Table 1 and that of CBC prepared from the former in Table 2. ... 

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