Product recovery efficiency

The design of a stirred tank fermenter for the production of an industrial enzyme at an annual rate of 800 5% mt/yr is illustrated below. Product recovery efficiency is 80% and the expected yield (product concentration) is 75kg/m. Maximum oxygen uptake demand is 185 mmol 02/L/hr. Operational parameters and media physical properties are listed as follows. 

Annual fermenter output = required production/ recovery efficiency = 800mt/yr/0.8 = 10 mt/yr. 

A more exacting measure of screening efficiency is referred to as product recovery efficiency. It is expressed as a percentage based on the amount of on-size product in the product fraction separated by the screener, divided by the amount of on-size material available in the feed to the screener. Product recovery is calculated as follows ... 

The example shown in Figure 24.4 is a typical screening application in which a screener is used to extract on-size product from a process flow. The example illustrates the relationship between product quality, product yield, and product recovery efficiency. 

In opt mazing any separation process it becomes necessary lo compute the product recovery efficiency of the operation as a fuuciion of design variables. For crystallization operations the ihsoretical maximum product recovery or yield from (he crystallizer is defiand by [ha following general relationship ... 

NATURE OF THE PROCESSES, FEEDSTOCK CONVERSION, AND PRODUCT RECOVERY EFFICIENCY... 

A membrane filter which can uniformly remove all viral agents regardless of the size of the viral agent is not available. Part of the difficulty is that the efficient recovery of the biological product diminishes as the size difference between the vims and biological product lessens. Thus a balance needs to be met where vims removal and product recovery are optimized. 

The derivatives are hydroxyethyl and hydroxypropyl cellulose. AH four derivatives find numerous appHcations and there are other reactants that can be added to ceUulose, including the mixed addition of reactants lea ding to adducts of commercial significance. In the commercial production of mixed ethers there are economic factors to consider that include the efficiency of adduct additions (ca 40%), waste product disposal, and the method of product recovery and drying on a commercial scale. The products produced by equation 2 require heat and produce NaCl, a corrosive by-product, with each mole of adduct added. These products are produced by a paste process and require corrosion-resistant production units. The oxirane additions (eq. 3) are exothermic, and with the explosive nature of the oxiranes, require a dispersion diluent in their synthesis (see Cellulose ethers). 

A. J. Finn, "Cryogenic Purge Gas Recovery Boosts Ammonia Plan Productivity and Efficiency," Nitrogen (175), 25—32 (Sept.—Oct. 1988). 

Gas-Fired water heaters are also made more efficient by a variety of designs that increase the recov-ei y efficiency. These can be better flue baffles multiple, smaller-diameter flues submerged combustion chambers and improved combustion chamber geometry. All of these methods increase the heat transfer from the flame and flue gases to the water in the tank. Because natural draft systems rely on the buoyancy of combustion products, there is a limit to the recovery efficiency. If too much heat is removed from the flue gases, the water heater won t vent properly. Another problem, if the flue gases are too cool, is that the water vapor in the combustion products will condense in the venting system. This will lead to corrosion in the chimney and possible safety problems. 

Polar organic solvents readily precipitate exopolysaccharides from solution. The solvents commonly used are acetone, methanol, ethanol and propan-2-ol. Cation concentration of the fermentation liquor influences the amount of solvent required for efficient product recovery. In the case of propan-2-ol, increasing the cation concentration can lead to a four-fold reduction in die volume of solvent required to precipitate xanthan gum. Salts such as calcium nitrate and potassium chloride are added to fermentation broths for this purpose. 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

Key mechanisms important for improved oil mobilization by microbial formulations have been identified, including wettability alteration, emulsification, oil solubilization, alteration in interfacial forces, lowering of mobility ratio, and permeability modification. Aggregation of the bacteria at the oil-water-rock interface may produce localized high concentrations of metabolic chemical products that result in oil mobilization. A decrease in relative permeability to water and an increase in relative permeability to oil was usually observed in microbial-flooded cores, causing an apparent curve shift toward a more water-wet condition. Cores preflushed with sodium bicarbonate showed increased oil-recovery efficiency [355]. 

It should be noted that the operating parameters of the unit can be adjusted to suit the client s needs. These particular operating conditions were an attempt to maximise productivity (i.e. minimise capital cost) and minimise the waste volume. While the NaCl recovery efficiency is about 96%, the brine purity is not exceptionally good (43.4% sulphate removal). This is not considered a disadvantage, however, since the low removal efficiency can be compensated for by increasing the flow of feed that is treated by the system. If necessary, removal efficiencies of over 95 % can be obtained. 

The recoverability of hydrocarbon from the subsurface refers to the amount of mobile hydrocarbon available. Hydrocarbon that is retained in the unsaturated zone is not typically recoverable by conventional means. Additional amounts of hydrocarbon that are unrecoverable by conventional methods include the immobile hydrocarbons associated with the water table capillary zone. Residual hydrocarbon is pellicular or insular, and is retained in the aquifer matrix. With respect to recoverability, residual hydrocarbon entrapment can result in volume estimate discrepancies as well as decreases in recovery efficiency. With increasing water saturation, such as when the water table rises via recharge or product removal, hydrocarbons essentially become occluded by a continuous water phase. This results in a reduction of LNAPL and product thickness as measured in the well at constant volume. When water saturation is decreased by lowering the water table (as during recovery operations), trapped hydrocarbons can remobilize, leading to increased recoverability. 

The potential of these reactions for methane production can be compared in terms of theoretical yields and heat recovery efficiencies. Theoretical methane yield is defined by the chemical equations. Theoretical heat recovery efficiency is defined as the percent of the higher heating value of the coal which is recovered in the form of methane product. These idealized parameters provide a measure of the ultimate capability of conversion systems and are useful for evaluating actual conversion processes. 

Steam conversion/methanation has a theoretical heat recovery efficiency of 1005L Hydrogen conversion has a theoretical efficiency of about 90%, if the production of hydrogen by steam conversion is taken into account, however, the theoretical efficiency drops to 81%. Oxygen conversion/methanation has a theoretical efficiency of only 61 which is the lowest of the conversion systems. 

Practical conversion processes can only approach the theoretical efficiencies shown in Table 3. The coal conversion reactions do not proceed to completion at ambient temperatures within practical time limitations. As a result, a portion of the coal feedstock must be burned to supply heat so that the reactions can be carried out at elevated temperatures and pressure where the rates of conversion are rapid. In practical systems, this additional heat can only be partially recovered. Consequently, practical conversion processes have actual heat recovery efficiencies of about 60-70% for production of high H/C ratio products. Production of secondary fuels having somewhat lower H/C ratio, i.e. about 2.0, permits attainment of heat recovery efficiencies of 70 to 80j. 

Liquid multiphasic systems, where one of the phases is catalyst-philic, are attractive for organic transformation, as they provide built-in methods of catalyst separation and product recovery, as well as advantages of catalytic efficiency. The present chapter focuses on recent developments of catalyst-philic phases used in conjunction with heterogeneous catalysts. Interest in this field is fueled by the desire to combine the high catalytic efficiency typical of homogeneous catalysis with the easy product-catalyst separation features provided by heterogeneous catalysis and in situ phase separations. 

Although biotechnological processes often have been stated to be energy efficient in that the reaction temperature is low, it is important to realize that the product concentrations are low and that the product recovery step is often the most energy consuming. 

Acidic pesticides and metabolites were concentrated from aqueous solution by the anion procedure of Richard and Fritz (10). The anionic materials in these concentrates were methylated using diazomethane and the derivatized products were separated and detected by gas chromatography. Test results of the recovery efficiencies by this method for several pesticides and suspected metabolites have been reported elsewhere (11). An overall recovery of 93% was achieved for sixteen acidic pesticides and metabolites spiked into water at 200 ppb. 

Baghouse systems efficiently control particulate emissions from grinding and blending processes. Vents from feed hoppers, crushers, pulverizers, blenders, mills, and cyclones are typically routed to baghouses for product recovery. This method is preferable to using wet scrubbers. However, even scrubber effluent can be largely eliminated by recirculation. 

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