Adding or removing

As pointed out in Chap. 5, replacing simple columns by complex columns tends to reduce the vapor (and heat) load but requires more of the heat to be added or removed at extreme levels. This means that the introduction of complex columns in the design might prejudice heat integration opportunities. Thus the introduction of complex distillation arrangements needs to be considered simultaneously with the heat integration. This can be carried out manually with some trial and error or using an automated procedure such as that of Kakhu and Flower. ... 

In this model, both the parent molecule and the species generated by adding or removing an electron are treated at the single-detemiinant level. 

Within this model, the energy difference between the daughter and the parent can be written as follows (i ) represents the particular spin orbital that is added or removed) ... 

Increasing or decreasing the partial pressure of a gas is the same as increasing or decreasing its concentration. The effect on a reaction s equilibrium position can be analyzed as described in the preceding example for aqueous solutes. Since the concentration of a gas depends on its partial pressure, and not on the total pressure of the system, adding or removing an inert gas has no effect on the equilibrium position of a gas-phase reaction. 

Under isothermal conditions where energy is not added or removed from the system, the second law of thermodynamics obtains, and... 

The filter press has the advantage of simplicity, low capital cost, flexibility, and ability to operate at high pressure in either a cake-filter or a clarifying-filter application. Floor-space and headroom needs per unit of filter area are small, and capacity can be adjusted by adding or removing plates and frames. Filter presses are cleaned easily, and the filter medium is easily replaced. With proper operation a denser, drier cake compared with that of most other filters is obtained. 

Since pipe flow is more nearly isenthalpic, the flash fraction x is found from an enthalpy balance between the stagnation point and a point z downstream. Accounting for changes in potential energy, kinetic energy, and heat added or removed from the pipe Q, x is given by ... 

The alternate method uses the proximity probes and an oscilloscope. A Lissajous figure is established on the oscilloscope. The orbit pattern and the keyphase mark are used to generate a vector. Weights are added or removed and the changes in the orbit are noted. Triangulation is used to anticipate the next move. For more complete information or technique, the reader is referred to a book on the subject by Jackson [ 1 ]. 

A salient feature of the fluidized bed reactor is that it operates at nearly constant temperature and is, therefore, easy to control. Also, there is no opportunity for hot spots (a condition where a small increase in the wall temperature causes the temperature in a certain region of the reactor to increase rapidly, resulting in uncontrollable reactions) to develop as in the case of the fixed bed reactor. However, the fluidized bed is not as flexible as the fixed bed in adding or removing heat. The loss of catalyst due to carryover with the gas stream from the reactor and regenerator may cause problems. In this case, particle attrition reduces their size to such an extent where they are no longer fluidized, but instead flow with the gas stream. If this occurs, cyclone separators placed in the effluent lines from the reactor and the regenerator can recover the fine particles. These cyclones remove the majority of the entrained equilibrium size catalyst particles and smaller fines. The catalyst fines are attrition products caused by... 

The operation might be feasible under adiabatie eonditions when no heat is added or removed from the reaetor (i.e., Q = 0), and the heat given up by the reaetion is entirely used within the system to ehange its enthalpy. The inlet temperature of feed reaetant is determined as follows. 

Table 6.18 shows the effect of adding or removing garments on the preferred operative temperature. By individual adaption of clothing it is prrssible to compensate for individual differences in preferred temperature or for differences in activity level. The table is based on ISO EN 7730 and ISO EN 9920. 

The process heat duty is the heat required to be added or removed from the proce.ss fluids to create the required change in temperature. This can he in the form of sensible heat, latent heat, or both. 

Since only one molecule is added to (or removed from) the system, U is simply the interaction of the added (or removed) molecule with the remaining ones. If one attempts to add a new molecule, N is the number of molecules after addition, otherwise it is the number of molecules prior to removal. If a cutoff for the interaction potential is employed, long-range corrections to must be taken into account because of the density change of /As. Analytic expressions for these corrections can be found in the appendix of Ref. 33. 

The Conjugate Peak Refinement (CPR) method may be eonsidered as a dynamical version of the chain method, where points are added or removed based on a sequenee of maximizations along line segments and minimizations along the conjugate directions. 

The second part of the first law of thermodynamics arises when the requirement that the process be adiabatic is dropped recall that this means the system is not insulated, and processes can be caused by heating and cooling. In a general process (the only assumption is that matter is not added or removed from the system), if an amount of work W is done on the system and the energy changes by DE then the heat supplied to the system Q is defined by... 

Dynamic imbalance is any imbalance resolved to at least two correction planes (i.e., planes in which a balancing correction is made by adding or removing weight). The imbalance in each of these two planes may be the result of many imbalances in many planes, but the final effects can be characterized to only two planes in almost all situations. 

No heat is being added or removed in this process, so the enthalpy must remain constant, and the process is shown as a movement along the line of constant enthalpy. Latent heat will be taken in by the water, from the sensible heat of the air, until the mixture reaches saturation, when no more water can be evaporated. 

When we are dealing with electrolytes, two species of particles (positive and negative ions) are added to or removed from a solution at the same time. In the case of a uni-divalent solute, three particles arc added or removed at the same time. Since the cratic term depends only on the numbers of particles of various species that have been mixed, electrolytes that are completely dissociated in solution must be classified. according to their valence types—uni-univalent, di-divalent, and so on. Then in any very dilute solution the correct assertion to make is that the cratic term will have the same value for all electrolytes of the same valence type. 

Referring to Fig. 9, it will be recalled that the curve of Fig. 96 differs from the curve of Fig. 9a because, when the ion is introduced into the solvent, the molecular dipoles in the co-sphere of the ion lose a certain amount of free energy. The co-sphere of each ion thereby makes a contribution (positive or negative) to the e.m.f. of the cell. For-each ion added or removed, the cratic term likewise makes a contribution to the e.m.f. fi of the cell. 

It is possible to use K to calculate the extent to which reaction occurs when an equilibrium is disturbed by adding or removing a product or reactant To show how this is done, consider the effect of adding hydrogen iodide to the HI-H2-I2 system (Example 12.7). 

Energy is usually added or removed from a system as heat or work. An adiabatic process is one in which energy, in the form of heat,6 is not allowed to... 

In an isothermal process, heat must be added during an expansion and removed during a compression to keep the temperature constant. We will describe this more fully as we now calculate the heat added or removed in isobaric, isochoric, and isothermal processes. 

EXAMPLE 9.9 Sample exercise Predicting the effect of adding or removing reactants and products... 

When the equilibrium composition is perturbed by adding or removing a reactant or product, reaction tends to occur in the direction that restores the value of Q to that of K. 

J 9 Use Ee Chatelier s principle to predict how the equilibrium composition of a reaction mixture is affected by adding or removing reagents, compressing or expanding the mixture, or changing the temperature (Examples 9.9, 9.11, and 9.12). 

Radicals can be prepared from closed-shell systems by adding or removing one electron or by a dissociative fission. Generally speaking, the electron addition or abstraction can be performed with any system, the ionization potential and electron affinity being thermodynamic measures of the probability with which these processes should proceed. Thus, to accomplish this electron transfer, a sufficiently powerful electron donor or acceptor (low ionization potential and high electron affinity, respectively) is required. If the process does not proceed in the gas phase, a suitable solvent may succeed. 

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