Solid/liquid separation material balance

The first step is solvolysis and, as proposed by YU, we used phenol or phenol based solvents to perform the dissolution of wood, which should be complete, in order to avoid a difficult solid-liquid separation. So we carried out a lot of experiments in order to find the optimal conditions, i.e., a quantity of phenolic solvent as small as possible, low temperature and low pressure. Analysis of material balances of different runs shows that it is necessary to keep the weight solvent/wood above 4. To complete the dissolution of wood, the minimum amounts of water and phenol in the solvent mixture are respectively 20 wt % and 25 wt % (Figures l.a and l.b). In this case, the liquid phase is completed... 

Abstract Unsteady liquid flow and chemical reaction characterize hydrodynamic dispersion in soils and other porous materials and flow equations are complicated by the need to account for advection of the solute with the water, and competitive adsorption of solute components. Advection of the water and adsorbed species with the solid phase in swelling systems is an additional complication. Computers facilitate solution of these equations but it is often physically more revealing when we discriminate between flow of the solute with and relative to, the water and the flow of solution with and relative to, the solid phase. Spacelike coordinates that satisfy material balance of the water, or of the solid, achieve this separation. Advection terms are implicit in the space-like coordinate and the flow equations are focused on solute movement relative to the water and water relative to soil solid. This paper illustrates some of these issues. 

Caloric occupied a special place in Lavoisier s system of chemistry because of its role in determining chemical constitution. All bodies in nature could assume the states of solid, liquid, and gas, depending on the proportion which takes place between the attractive force inherent in their particles, and the repulsive power of the heat acting upon these. The cause of heat or caloric was likely to be a real and material substance. It was the repulsive cause, whatever that may be, which separates the particles of matter from each other. The balance of the attractive force between the particles of a body and the repulsive force... 

Material balance calculations on separation processes follow the same procedures used in Chapters 4 and 5. If the product streams leaving a unit include two phases in equilibrium, an equilibrium relationship for each species distributed between the phases should be counted in the degree-of-freedom analysis and included in the calculations. If a species is distributed between gas and liquid phases (as in distillation, absorption, and condensation), use tabulated vapor-liquid equilibrium data, Raoult s law, or Henry s law. If a solid solute is in equilibrium with a liquid solution, use tabulated solubility data. If a solute is distributed between two immiscible liquid phases, use a tabulated distribution coefficient or equilibrium data. If an adsorbate is distributed between a solid surface and a gas phase, use an adsorption isotherm. 

Among engineers, population balance concepts are of importance to aeronautical, chemical, civil (environmental), mechanical, and materials engineers. Chemical engineers have put population balances to the most diverse use. Applications have covered a wide range of dispersed phase systems, such as solid-liquid dispersions (although with incidental emphasis on crystallization systems), and gas-liquid, gas-solid, and liquid-liquid dispersions. Analyses of separation equipment such as for liquid-liquid extraction, or solid-liquid leaching and reactor equipment, such as bioreactors (microbial processes) fluidized bed reactors (catalytic reactions), and dispersed phase reactors (transfer across interface and reaction) all involve population balances. 

To perform a balance, a control volume (C.V.) must be identified first to isolate the system and the surroundings with respect to the balance. The surface of this control volume, as shown in Figure 3.1, is termed the control surface. The control volume is chosen to isolate the volume for evaluation, such as a complete separation process or just a specific portion. The control surface is chosen to identify the flow of mass into or out of the control volume. An open (or flow) system is one in which material is transferred across the control surface, that is, enters the C.V., leaves the C.V., or both. A closed (or batch) system is one in which there is no such transfer during the time interval for evaluation. Consider a vessel in which water is added that contains some dissolved organics and activated carbon. If the equilibration of the liquid and solid phases is of primary interest, then the system can be treated as a closed system if the vessel is selected as the C.V. If... 

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