Southern


The most frequent application of phase-equilibrium calculations in chemical process design and analysis is probably in treatment of equilibrium separations. In these operations, often called flash processes, a feed stream (or several feed streams) enters a separation stage where it is split into two streams of different composition that are in equilibrium with each other.  [c.110]

In an equilibrium separation, a feed stream containing m components at given composition, pressure, and enthalpy (or temperature if in a single phase) is split into two streams in equilibrium, here taken to be a vapor and a liquid. The flow rates of the feed, vapor, and liquid streams are, respectively,  [c.111]

Vector (length 20) of stream composition (I = 1,N). Contribution from temperature dependence of UNIQUAC binary interaction parameters, here taken as 0.  [c.296]

The temperature and composition of each feed stream and the stream ratios are specified along with a common feed pressure (significant only for the vapor stream) and the flash pressure. For an isothermal flash the flash temperature is also specified. Resulting vapor and liquid compositions, phase ratios, vaporization equilibrium ratios, and, for an adiabatic flash, flash temperature are returned.  [c.319]

PF pressure of vapor feed stream (bar)  [c.320]

HL Enthalpy of exiting liquid stream, J/mole.  [c.321]

HLF Enthalpy of liquid feed stream, J/mole.  [c.321]

HV Enthalpy of exiting vapor stream, J/mole.  [c.321]

HVF Enthalpy of vapor feed stream, J/mole.  [c.321]

Figure 2.8 shows the essential features of a refinery catalytic cracker. This particular reaction is accompanied hy the deposition of carhon on the surface of the catalyst. The fiuidized-hed reactor allows the catalyst to he withdrawn continuously and circulated to a fiuidized regenerator, where the carhon is burnt ofi" in an air stream, allowing regenerated catalyst to he returned to the cracker.  [c.59]

Drying refers to the removal of water from a substance through a whole range of processes, including distillation, evaporation, and even physical separations such as with centrifuges. Here, consideration is restricted to the removal of moisture from solids and liquids into a gas stream (usually air) by heat, namely, thermal drying. Some of the types of equipment for removal of water also can be used for removal of organic liquids from solids.  [c.89]

If the vapor stream consists of a mixture of unconverted feed material, products, and byproducts, then some separation of the vapor may be needed. The vapor from the phase split is difficult to condense if the feed has been cooled to cooling water temperature. If separation of the vapor is needed, one of the following methods can be used  [c.108]

The reactor effluent is thus likely to contain hydrogen, methane, benzene, toluene, and diphenyl. Because of the large differences in volatility of these components, it seems likely that partial condensation will allow the effluent to be split into a vapor stream containing predominantly hydrogen and methane and a liquid stream containing predominantly benzene, toluene, and diphenyl.  [c.110]

The hydrogen in the vapor stream is a reactant and hence should be recycled to the reactor inlet (Fig. 4.8). The methane enters the process as a feed impurity and is also a byproduct from the primary reaction and must be removed from the process. The hydrogen-methane separation is likely to be expensive, but the methane can be removed from the process by means of a purge (see Fig. 4.8).  [c.110]

The liquid stream can be separated readily into pure components by distillation, the benzene taken ofif as product, the diphenyl as an unwanted byproduct, and the toluene recycled. It is possible to recycle the diphenyl to improve selectivity, but we will assume that is not done here.  [c.111]

Assume initially that a phase split can separate the reactor effluent into a vapor stream containing only hydrogen and methane and a liquid stream containing only benzene, toluene, and diphenyl and that the liquid separation system can produce essentially pure products.  [c.111]

Can the useful material lost in the purge streams be reduced by additional reaction If the purge stream contains significant quantities of reactants, then placing a reactor and additional separation on the purge can sometimes be justified. This technique is used in some designs of ethylene oxide processes.  [c.125]

The analysis of the heat exchanger network first identifies sources of heat (termed hot streams) and sinks (termed cold streams) from the material and energy balance. Consider first a very simple problem with just one hot stream (heat source) and one cold stream (heat sink). The initial temperature (termed supply temperature), final temperature (termed target temperature), and enthalpy change of both streams are given in Table 6.1.  [c.160]

Steam is available at 180°C and cooling water at 20°C. Clearly, it is possible to heat the cold stream using steam and cool the hot stream using cooling water. However, this would incur excessive energy costs. It is also incompatible with the goals of sustainable industrial activity, which call for use of the minimum energy practicable. Instead, it is preferable to try to recover heat, if this is possible. The scope for heat recovery can be identified by plotting both streams on temperature-enthalpy axes. For feasible heat exchange between the two streams, the hot stream must be hotter than the cold stream at all points. Figure 6.1a shows the temperature-enthalpy plot for this problem with a minimum temperature difference of 10°C. The  [c.160]

TABLE 6.1 Two-Stream Heat Recovery Problem  [c.160]

Consider the simple flowsheet shown in Fig. 6.2. Flow rates, temperatures, and heat duties for each stream are shown. Two of the streams in Fig. 6.2 are sources of heat (hot streams) and two are sinks for heat (cold streams). Assuming that heat capacities are constant, the hot and cold streams can be extracted as given in Table 6.2. Note that the heat capacities CP are total heat capacities and  [c.161]

Figure 6.1 A simple heat recovery problem with one hot stream and one cold stream. Figure 6.1 A simple heat recovery problem with one hot stream and one cold stream.
Within each temperature range the streams are combined to produce a composite hot stream. This composite hot stream has a CP  [c.162]

TABLE 6.2 Heat Exchange Stream Data for the Flowsheet in Fig. 6.2  [c.162]

The temperatures or enthalpy change for the streams (and hence their slope) cannot he changed, but the relative position of the two streams can be changed by moving them horizontally relative to each other. This is possible because the reference enthalpy for the hot stream can be changed independently from the reference enthalpy for the cold stream. Figure 6.16 shows the same two streams moved to a different relative position such that AT ,in is now 20°C. The amount of overlap between the streams is reduced (and hence heat recovery is reduced) to 10 MW. More of the cold stream extends beyond the start of the hot stream, and hence the amount of steam is increased to 4 MW. Also, more of the hot stream extends beyond the start of the cold stream, increasing the cooling water demand to 2 MW. Thus this approach of plotting a hot and a cold stream on the same temperature-enthalpy axis can determine hot and cold utility for a given value of Let us now extend this approach to many hot  [c.161]


See pages that mention the term Southern : [c.148]    [c.173]    [c.173]    [c.174]    [c.174]    [c.174]    [c.175]    [c.175]    [c.176]    [c.176]    [c.176]    [c.177]    [c.177]    [c.177]    [c.178]    [c.178]    [c.178]    [c.295]    [c.319]    [c.48]    [c.48]    [c.90]    [c.108]    [c.109]    [c.160]    [c.160]   
13 Chemistry in the Marine Environment (2000) -- [ c.28 ]