Product recovery specifications

Once we have obtained convergence with the top and bottom products only, we will add the side strippers in a consecutive fashion. We illustrate this process for the heavy naphtha side stripper only, but it is identical for all side strippers. In Aspen HYSYS, the Side-Ops tab allows the user to insert side operations in the main column. By adding the side operations directly to the main column, we have a great deal of flexibility when assigning column or product recovery specifications. We show the Side-Ops tab in Figure 2.37. 

Fermentation broths are complex, aqueous mixtures of cells, comprising soluble extracellular, intracellular products and any unconverted substrate or unconvertible components. Recovery and extraction of product is important in bioprocess engineering. In particular separation is a useful technique it depends on product, its solubility, size of the process, and product value. Purification of high-value pharmaceutical products using chromatography such as hormones, antibody and enzymes is expensive and difficult to scale up.1 Tire necessary steps to follow a specific process depend on the nature of the product and the characteristics of the fermentation broth. There are a few steps for product recovery the following processes are discussed, which are considered as an alternative for product recovery from fermentation broth. 

Bridonneau. R, Bunch, S., Tengler, R., Hill, K., Carter, J., Pieken, W., Tinner-meier, D., Lehrman, R., and Drolet, D. W., Purification of a highly modified RNA-aptamer. Effect of complete denaturation during chromatography on product recovery and specific activity, /. Chromatogr. B, 726, 237, 1999. 

The design and capacity of an RO unit is dependent upon the type of chemicals in the plating solution and the dragout solution rate. Certain chemicals require specific membranes. For instance, polyamide membranes work best on zinc chloride and nickel baths, and polyether/amide membranes are suggested for chromic acid and acid copper solutions. The flow rate across the membrane is very important. It should be set at a rate to obtain maximum product recovery. RO systems have a 95% recovery rate with some materials and with optimum membrane selection.22... 

The combination of C02 injection and methane production over specific PT regimes allows the heat effects of C02 hydrate formation and methane hydrate decomposition to nullify each other resulting in a sustainable delivery process which both reduces C02 emissions to combat global warming and recovers methane to supplement the declining reserves of conventional natural gas (Fig. 4). This gas hydrate phase-behaviour in response to the dissociation and formation processes clearly demonstrates the potential of C02 enhanced CH4 recovery from the Mallik gas hydrate deposit. 

The Resource Conservation and Recovery Act (RCRA) identifies endrin as a hazardous waste in two ways (1) when it exceeds a toxicity characteristic leaching procedure test concentration of 0.02 mg/L (EPA 1980a) and (2) when it is discarded as a commercial chemical product, off-specification species, container residue, or spill residue (EPA 1980a). 

The second desorbent characteristic is that the desorbent material must be compatible with both the particular adsorbent and the feed mixture. Specifically, the desorbent must not reduce the capacity of the adsorbent or normal paraffin selectivity with respect to the raffinate components. Additionally, desorbent materials must not react with any feed component Both the extract stream and the raffinate streams consist of a mixture of feed components with desorbent and any chemical reaction prevent product recovery. 

In some cases, wastewater can be substantially reduced by substituting an organic solvent for water in the synthesis and separation steps of the production process, with subsequent solvent recovery. Specific pollutants can be eliminated by requesting specification changes from raw material suppliers in cases when impurities are present and known to be discharged in process... 

Finally, it should be noted that this general technique may be used for a wide variety of separation processes in addition to immunoassays, where the isolation of a specific component in a biological fluid, industrial process stream or body of water is desired. Thus, product recovery and/or toxin or pollutant removal processes are possible with this methodology. 

Recovery of reactants, intermediates, or APIs from mother liquors or filtrates is acceptable as long as the procedures used meet in-process product/ process specifications. Solvents can be recovered and reused as long as the procedures employed are adequately documented. 

With some modification, the immobilized process for ECB may also be applicable to other insoluble hydrophobic substrates. Modification of the immobilized ECB process may include specific binding resins for enzymatic conversion and for product recovery. 

The integration of two unit operations lies at the heart of process engineering. More often in bioprocesses it is the integration of product formation with the following recovery steps that is critical.5 In the specific case of biocatalytic processes the product recovery is also critical, but in this chapter the focus will be on the integration of the surrounding chemical steps with the biocatalysis. 

Note that while recoveries and product purity specifications for the key components are selected as independent decision variables in the outer loop, these should not be assigned arbitrary values. It is possible that certain purities may not be achievable with the current column configuration (this can be checked against the minimum number of plates, Nmin required for the given separation, Chapter 3), or due to the presence of azeotropes, etc. At the very least, the specifications must be consistent with the amounts of the various species present in the initial charge and in the feed state to each separation task (i.e. the overall mass balance must be satisfied). Thus care must be taken in selecting the outer loop specifications and bounds. 

Table 6.9. Recoveries and Product Specifications in Each Distillation Task in Figures 6.10 and 6.11. [Adopted from Mujtaba and Macchietto, 1994] Purities in bold face indicate the desired product specifications. Other purity and recovery specifications (decision variables of type (b are set at typical values.

As presented in the earlier chapters, the operating policy for a batch distillation column can be determined in terms of reflux ratio, product recoveries and vapour boilup rate as a function of time (open-loop control). Under nominal conditions, the optimal operating policy may be specified equivalently in terms of a set-point trajectory for controllers manipulating these inputs. In the presence of uncertainty, these specifications for the optimal operating policy are no longer equivalent and it is important to evaluate and compare their performance. 

Product rate specification. The product rate specification can be expressed simply as a flow rate. Alternatively, it can be expressed as a recovery." Some examples of the use of recovery specification are... 

A double-recovery specification is equivalent to specifying one product rate and one product purity. For instance, 95 percent of the light key in the feed is to be recovered in the distillate, and 90 percent of the heavy key in the feed is to be recovered in the bottom. This sets both the distillate rate to (zLNK + 0.95zLK + 0,10zhk)F, and the heavy key concentration of the distillate at... 

Section 3.1.1 states that in a process design, a separation is specified in terms of purities and product flows. For a simple column, two specifications are made and at least one must be a purity. Section 3.1.1 also states that the purity specification can be substituted by a physical property which is a function of the purity or composition, while a product flow can be substituted by a recovery specification. 

More than one product purity or recovery specification Not all methods will accept or solve. Replace one purity specification with some other such as reflux rate or a product rate. The methods best suited to solve multiple purity specifications are the inside-out methods (Sec. 4.3.1). 

Combining purify or recovery and product flow specifications These may clash, especially on binary systems. Free one and find something else to specify. 

Modifications to this process can be made to effect recovery of neptunium, americium, curium, californium, strontium, cesium, technetium, and other nuclides. The efficient production of specific transuranic products requires consideration of the irradiation cycle in the reactor and separation of intermediate products for further irradiation. 

However from the standpoint of green chemistry, the use of isolated enzymes (or dead whole cells) is highly preferred because it avoids the generation of copious amounts of biomass. It must be emphasized that the productivity of microbial conversions is usually low, since non-natural substrates are only tolerated at concentrations as low as 0.1-0.3% [106]. The large amount of biomass present in the reaction medium causes low overall yields and makes product recovery troublesome. Therefore the E-factors for whole cell processes can be extremely high. Moreover the use of wild-type cells often causes problems because an array of enzymes is present which can interfere in the reduction of a specific ketone (giving opposite selectivities). The use of recombinant techniques, however, which only express the desired enzyme can overcome this problem [108]. 

Step 8. Several control valves now remain unassigned. Steam flow to the trim heater controls reactor inlet temperature. Cooling water flow to the trim cooler is used to control the exit process temperature and provide the required condensation in the reactor effluent stream. Liquid recirculation in the absorber is flow-controlled to achieve product recovery, while the cooling water flow to the absorber cooler controls the recirculating liquid temperature. Acetic acid flow to the top of the absorber is flow-controlled to meet recovery specifications on the overhead gas stream. Cooling water flow to the cooler on this acetic acid feed to the absorber is regulated to control the stream temperature. Cooling water flow in the column condenser controls decanter temperature. 

The pyrolysis furnace effluent is processed for heat and product recovery in an efficient, low-cost recovery section. The recovery section design can be optimized for specific applications and/or selected based on operating company preferences. Flow schemes based on demethanizer first, deethanizer first and depropanizer first configurations are available for particular applications. Shown above is the depropanizer first scheme, which is primarily applicable to liquid crackers. 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

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