Fixed productivity

Fixed-product ion scans (sector instruments). High-voltage scan or linked scan at constant B /E. Both techniques give a spectrum of all precursor (parent) ions that fragment to yield a preselected product (daughter) ion. 

Clear-Hquor advance reduces the quantity of Hquor that must be processed by soHd—Hquid separation equipment (for example, a filter or a centrifuge). The reduction in Hquor flow through the separation equipment may allow use of smaller equipment for a fixed production rate or increased production through fixed equipment. 

Total variable production cost plus fixed production overhead cost. 

Total cost. (This includes variable and fixed production and general expenses.)... 

A large number of parameters are involved in the choice of the corrosion protection system and the provision of the proteetion eurrent these are deseribed elsewhere (see Chapters 6 and 17). In partieular, for new locations of fixed production platforms, a knowledge of, for example, water temperature, oxygen content, conductivity, flow rate, chemical composition, biological activity, and abrasion by sand is useful. Measurements must be carried out at the sea location over a long period, so that an increased margin of safety can be calculated. 

Other established attempts on heat integration of batch plants are based on the concept of pinch analysis (Linnhoff et al., 1979 Umeda et al., 1979), which was initially developed for continuous processes at steady-state. As such, these methods assume a pseudo-continuous behaviour in batch operations either by averaging time over a fixed time horizon of interest (Linnhoff et al., 1988) or assuming fixed production schedule within which opportunities for heat integration are explored (Kemp and MacDonald, 1987, 1988 Obeng and Ashton, 1988 Kemp and Deakin, 1989). These methods cannot be applied in situations where the optimum schedule has to be determined simultaneously with the heat exchanger network that minimises external energy use. 

Besides all these quant-related constraints there are numerous others such as down times for production equipment when maintenance or rebuilding activities have to be carried out or fixed production orders. Finally, there are constraints such as varying shift models, and so forth. 

Supply costs on the left side of the figure are volatile mainly caused by volatile procurement volumes and prices within supply, fixed production costs are given and not decision relevant in the short/medium term ... 

Resource value fixed production costs cfc, Vr e i in the resource-specific currency are input data not decision-relevant for optimization, but being used in order to calculate earnings before tax profits. Production fixed costs include the value depreciation of the resource, shift personnel costs and other fixed production-related cost blocks. 

The production cost index combines variable and fixed production costs. 

Figure 3.5. Schematic of precursor ion scan (PIS). Q3 is set to pass a fixed product ion and Q1 is set to scan through a desired mass range and all the ions within that desired mass range are fragmented in the collision cell (Q2). Thus, a precursor ion mass spectrum shows all the precursor ions that fragmented to form the product ion set to pass through Q3.

In RO, a colloidal deposit on the membrane introduces an additional resistance, Rf, and could also cause cake-enhanced concentration osmotic pressure (CEOP) [24]. The CEOP phenomenon is discussed in Section 6.3.4. Large-scale RO plants tend to be operated at a fixed production rate, requiring a fixed average flux. 

Clear-liquor advance is used for two purposes (1) to reduce the quantity of liquor that must be processed by the solid-liquid separation equipment (e.g., filter or centrifuge) that follows the crystallizer, and (2) to separate the residence time distributions of crystals and liquor. The reduction in liquor flow through the separation equipment can allow the use of smaller equipment for a fixed production rate or increased production through fixed equipment. Separating the residence time distributions of crystals and liquor means that crystals will have an average residence time longer than that of the liquor. This should, in principle, lead to the production of larger crystals, but because the crystallizer is otherwise well mixed, the crystal population density will have the same form as that for the MSMPR crystallizer (Eq. (54)). 

One advantage in using specific detection to monitor the effluent from a preparative chromatographic process is that it becomes a simple matter to maximize the yield of the desired component for a fixed product purity. In particular, if Ai and A ee(1 are the amounts of component i in the product fraction and feed slug, respectively, and if component 2 is the desired component, then Pp, Pu, Pd, Y, and dA(- are given as follows (see Figure 2) ... 

Mujtaba and Macchietto (1992) investigated how productivity (kmol of product/hr) is affected by the proposed recycle policy. Consider a fixed vapour load to the condenser (or vapour boilup rate) and fixed product compositions (e.g. xlDi and x1 B2 for recycle loop 1 of Figure 8.13). Now scale the batch times (presented as... 

As mentioned earlier in Section III,C, 6, 3-amino-2,l-benziso-thiazole displays reactions which yield fixed products of the tautomeric 3-imino form. Ross has prepared a number of 3-alkylimino and 3-arylimino derivatives.103... 

Objective Function. The objective of the optimization is to minimize the total cost of owning and operating the system (at fixed product output). The objective function must be expressed in terms of the system s costs (fuel, equipment, and capital) by using an amortized capital investment, Z, for each component and the total fuel cost, CFUEL, written per operating hour. The objective function may be written as... 

The treatment of conflicting specifications leading to convergence problems has been developed elsewhere [7]. For example, this situation arrives when the distillation columns are specified by fixed product flow rates. These specifications, correct for standalone columns, lead to nonconvergence when the units are placed in recycles. The explanation is that during the iterative solution it is impossible to... 

In the second simulation (Figure 7.12b), the reactor-inlet flow was increased from 74000 kg/h to 81500kg/h. Initially, the amounts of VCM produced and of fresh EDC fed increase. However, these flows soon decrease to the initial values. This means that, when reaction conditions are fixed, production-rate changes can be achieved only at the expense of large variations of the recycle flow. Moreover, all the flow rates are very sensitive to disturbances if a control structure fixing the flow rate at the plant inlet is used. 

By referring back to the I- V relationship in Eqs. (6) and (17) and Rs expressed in terms offix in Eq. (14), the fill factor and normalized efficiency, as shown in Fig. 11, are determined as a function of the electron /it product. These relationships shown in Fig. 11 could be tested by utilizing recent work by Faughnan, Moore, and Crandall in which the electron collection length in the cell s i layer at JT = Jx are determined from quantum efficiency measurements at various bias potentials applied to the cell (Faughnan et al., 1984). The collection length at V= 0 is a product of fix times the internal electric field and the internal field may be determined by the theory from the potential drop across Rs at JT = JK. Fill factor and efficiency data as a function of the fix product extracted from the electron collection length before and after extended cell illumination can be used to test this proposed model. 

This procedure can only be used for fixed vapor flows. If liquid flows are to be fixed, a more complicated procedure is needed and will not be developed here. For simple countercurrent systems it is usually possible to fix product liquid flows by fixing certain vapor flows. An obvious modification of the above procedure can be used to fix temperatures if desired. 

An interesting consideration arises when a fixed production of one chemical species, say Ai, is required. The rate at which Ai is being formed is qai c[ — Ca+i), so that for any given q the exit extent c[ is fixed. Suppose that x is known and either X or V is given in the latter case X is determined for any q as above. We now work backwards from the end, for the exit conditions must lie on F l where c = c[. Then proceeding successively to FhFzjFz, etc., by adiabatic or horizontal lines we shall eventually reach the line c = Cr+i. The point at which this is reached, however, is not necessarily an optimal... 

Fixed production costs are costs that are incurred regardless of the plant operation rate or output. If the plant cuts back its production, these costs are not reduced. Fixed... 

Optimal Design and Operation of Multivessel Batch Distillation Column with Fixed Product Demand and Strict Product Specifications... 

Unlike the past work, this work focuses on optimal design and operation of multivessel batch distillation column with fixed product demand and strict product specifications. Both the vapour load and number of stages in each column section are optimised to maximise a profit function. For a ternary mixture, the performance of the multivessel column is also evaluated against that of a conventional batch distillation column. Although the profitability and the annual capitalised cost (investment) of the multivessel column is within 2-3% compared to those of conventional column, the operating cost (an indirect measure of the energy cost and environmental impact) is more than 30% lower for multivessel column. Thus, for a given separation task, multivessel column is more environment friendly. 

Keywords Multivessel Batch Distillation, Fixed Product Demand, Product Sequence, Optimisation. 

Given-. The column configuration (MultiVBD or Conventional), fixed product... 

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