Liquid/solid ratio required

The derivation of equation 90 requires that the parameter is a constant for the cake as a whole. The compressibility of the filter cake, however, gives rise to a non-uniform liquid solid ratio through the filter cake. Figure 34, from Sherwood et al. (130), shows the variation of the void fraction ec, defined by... 

Intact-rock techniques involve more realistic surface areas and liquid solid ratios, but the experimental equipment is generally more complex and timescales are longer. It is recognized that machining of the samples to the required size and shape may result in some alteration to the rock surface. This effect could be important in the case of strongly sorbing radionuclides where the depth of penetration will be very small over typical laboratory timescales (e.g. 1-2 years). 

By and large, ejectors and motionless mixers have similar mass transfer performance at a given gas-to-liquid flow ratio and energy input. However, ejectors have a number of benefits and drawbacks compared to a motionless mixer. On the positive side, the ejector suction means that a pressurized gas supply is not required. The unrestricted mixing tube means that solid formation due to reaction is not problematic. Against this, the operation is sensitive to changes in the gas-liquid flow ratio and diameter/length ratio. Gas-to-liquid flow ratios are also more limited in ejectors. 

Rotary wheel atomizers require 0.8 to 1.0 kWh/1000 L. The lateral throw of a spray wheel requires a large diameter to prevent accumulation on the wall the ratio of length to diameter of 0.5 to 1.0 is in use in such cases. The downward throw of spray nozzles permits smaller diameters but greater depths LID ratios of 4 to 5 or more are used. Spray vessel diameters of 15 m (50 ft) or more are known. Liquid/gas ratios are 0.2 to 0.3 gal/MSCF. Flue gas enters at 149°C (300°F) at a velocity of 2.44 m/s (8 ft/s). Utilization of 80 percent of the solid reagent may be approached. Residence times are 10 to 12 s. At the outlet the particles are made just dry enough to keep from sticking to the wall, and the gas is within 11 to 28°C (20 to 50°F) of saturation. The fine powder is recovered with fabric filters. In one test facility, a gas with 4000 ppm S02 had 95 percent removal with lime and 75 percent removal with limestone. 

The most commonly encountered coexisting phases in industrial practice are vapor and liquid, although liquid/liquid, vaporlsolid, and liquid/solid systems are also found. In this chapter we first discuss the nature of equilibrium, and then consider two rules that give the lumiber of independent variables required to detemiine equilibrium states. There follows in Sec. 10.3 a qualitative discussion of vapor/liquid phase behavior. In Sec. 10.4 we introduce tlie two simplest fomiulations that allow calculation of temperatures, pressures, and phase compositions for systems in vaporlliquid equilibrium. The first, known as Raoult s law, is valid only for systems at low to moderate pressures and in general only for systems comprised of chemically similar species. The second, known as Henry s law, is valid for any species present at low concentration, but as presented here is also limited to systems at low to moderate pressures. A modification of Raoult s law that removes the restriction to chemically similar species is treated in Sec. 10.5. Finally in Sec. 10.6 calculations based on equilibrium ratios or K-values are considered. The treatment of vapor/liquid equilibrium is developed further in Chaps. 12 and 14. 

Planning to optimize slurry preparation. The slurries must have analyte concentrations that are appropriate for the analyte line selected. The factors of interest include homogeneity of the solid, distribution of the analyte in the solid, density, particle size and analyte partitioning in the slurry. If the analyte distribution in the solid is heterogeneous, one must strive for very small (< 10 pm) particles. The minimum mass required for analysis based on particle size and density should be computed. The volume-to-volume ratio (solid volume/liquid volume ratio) should be computed in order to ensure that it is lower than 0.25. 

How many stages are required to achieve 95% hypericins extraction with a liquid-to-solids ratio of 10 ... 

The major difficulties with a liquid-solid extraction were that the distribution ratios of the desired products were low the process was slow and large amounts of solvent were required, which then had to be removed. What was desired was an apparatus that could (1) hold finely divided solid particles so a large surface area could be exposed, (2)... 

Stoichiometry and Solids Dissolution. One thousand cu ft of gas at standard conditions contains 3.16 g moles of sulfur dioxide when the sulfur dioxide content of the gas is 2500 ppm. At a liquid-to-gas ratio of 50 gal/standard 1000 cu ft, 16.7 mmoles of basic species/1. are required to react with this amount of sulfur dioxide. Very few of the simulated solutions in Tables III and IV attained this basicity except under extreme conditions of the variables, conditions unlikely to be controlled consistently in lime or limestone scrubbing. Consequently, under most conditions, additional basic species must enter the liquid phase in the scrubber to neutralize the dissolving gas. These species come from the dissolution of calcium carbonate or calcium sulfite in the scrubbing tower. The amount of solids dissolution required to achieve stoichiometry is reduced greatly by the presence of large amounts of magnesium in solution. 

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