Flow scheme

Early 60 s Separate Hydrotreating Low activity amorphous catalyst 

Mid 60 s Two Stage Hydrocracking Advent of zeolitic catalysts More economical scheme 

Late 60 s Single Stage More efficient design cost 

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Low temperature characteristics of a diesei fuei affect more its fuel feed system than its behavior when burning. However, we will examine them here because of their strong impact on refinery flow schemes. 

This type of study, applied over all the cuts, enables the refinery flow scheme to be defined in order to satisfy a given set of market conditions starting from one or more crude oil feedstocks. 

The preceding discussion on the role of refining and the development of flow schemes shows clearly the importance attributed to the characterization of crude oils and petroleum products. 

To give some structure to the process design it is common to present information and ideas in the form of process flow schemes (PFS). These can take a number of forms and be prepared in various levels of detail. Atypical approach is to divide the process into a hierarchy differentiating the main process from both utility and safety processes. 

For example a process flow scheme for crude oil stabilisation might contain details of equipment, lines, valves, controls and mass and heat balance information where appropriate. This would be the typical level of detail used in the project definition and preliminary design phase described in Section 12.0. 

Water may be injected into the reservoir to supplement oil recovery or to dispose of produced water. In some cases these options may be complementary. Water will generally need to be treated before it can be injected into a reservoir, whether it is cleaned sea water or produced water. Once treated it is injected into the reservoir, often at high pressures. Therefore to design a process flow scheme for water injection one needs specifications of the source water and injected water. 

The objective of managing the well performance in the process flow scheme shown in Figure 14.1 is to reduce the constraints which the well might impose on the production of the hydrocarbons from the reservoir. The well constraints which may limit the reservoir potential may be split into two categories the completion interval and the production tubing. The following table indicates some of the constraints ... 

A general work flow scheme - an iterative process - for the generation of conformations is shown in Figure 2-103. 

Figure 2-103. General work flow scheme for the generation of multiple conformations.

Since the 1960s the commercial development of continuous countercurrent processes has been almost entirely accompHshed by using a flow scheme that simulates the continuous countercurrent flow of adsorbent and process Hquid without the actual movement of the adsorbent. The idea of a simulated moving bed (SMB) can be traced back to the Shanks system for leaching soda ash (58). 

Eig. 1. Flow scheme of a typical silver catalyst process. S = steam CW = cooling water. 

Fig. 6. Flow scheme for manufacture of ethyl alcohol from corn.

Fig. 2. LP Oxo gas recycle flow scheme A, feedstock pretreatment B, reactor C, catalyst preparation and treatment systems D, condenser E, separator F,...

Fig. 3. LP Oxo liquid recycle flow scheme A and B, reactors C, vaporizer D, catchpot E, stabilizer F, syngas cleanup and G, propylene cleanup.

Fig. 5. Hoechst/Rhc ne-Poulenc oxo flow scheme A, stirred tank reactor B, separator C, phase separator D, stripping column E, heat exchanger and F,...

Food-grade specifications requite further purification in the form of carbon treatments and recrysta11i2ation from aqueous or other solvent systems. The illustrated flow scheme for sorbic acid production in Figure 1 has been greatly simplified. 

Regenerable absorption processes have also been developed. In these processes, the solvent releases the sulfur dioxide in a regenerator and then is reused in the absorber. The WelLman-Lord process is typical of a regenerable process. Figure 11 illustrates the process flow scheme. Sulfur dioxide removal efficiency is from 95—98%. The gas is prescmbbed with water, then contacts a sodium sulfite solution in an absorber. The sulfur dioxide is absorbed into solution by the following reaction ... 

Fig. 12. Flow scheme for the SASOL I Fischer-Tropsch process. To convert MPa to psig, multiply by 145.

Figure 16-49 [Engineering Data Book, 10th ed., Gas Processors Slippers Association, Tulsa, 1988, Sec. 20, p. 22] depicts the flow scheme for a typical two-bed TSA dryer system showing the auxiliary equipment associated with regeneration. Some of the diy product gas is externally heated and used couutercurreutly to heat and desorb water from the adsorber not currently drying feed. The wet, spent regeneration gas is cooled the water is condensed out and the gas is recycled to feed for recovery.

HG. 16-51 UOP nine-bed polybed PSA Ho unit a) flow scheme (h) cycle diagram. (Reference Fuderer and Rudelstotfer, U.S. Fatent numbef- 3,986,849, 1976.)... 

Two basic flow schemes are used tortuous path flow and sheet flow (Fig. 22-59). Tortuous path spacers are cut to provide a long path between inlet and outlet, providing a relatively long residence bme and high velocity past the membrane. The flow channel is open. Sheet flow units have a net spacer separating the membranes. Mass transfer is enhanced either by the spacer or by higher velocity. 

Performance of the power-recovery unit operating with a makeup driver (Fig. 29-56) is shown in Fig. 29-57 specific percentage values are shown, but the general characteristics and curwe shapes are typical. It should be noted that the flow scheme, the selection of... 

Figure 3-1. This example flow scheme for methane liquefaction uses compression, turboexpansion, and mechanical refrigeration.

The Sulfinol process from Shell Development Company is a good example of the physical/chemical type of process. It blends a physical solvent and an amine to obtain the advantages of both. The physical solvent is Sulfolane (tetrahydrothiophene dioxide) and the amine is usually DIPA (diisopropanol amine). The flow scheme is the same as for an amine plant. ... 

For stringent specifications of outlet H2S or CO2, special designs or a two-stage process may be required. Maddox states that a two-stage process would typically be used for acid gas feed concentrations of 20-40%. Maddox gives the following rules of thumb for process flow scheme selection ... 

Step 2.1 R ne the Initial Checklist. Table 1 is a checklist of unit operations. Apply this as an initial guide and checklist that can be used to identify each unit operation within the unit process that the audit will focus on. You may have to make additions to the list, because it is meant to be a general overview. Next to each unit operation that applies to the unit process of interest, provide a brief description of its function or purpose. This will prove useful in developing a process flow scheme in Step 3. Much of this sub-step can be accomplished by... 

Solution. As with all material-balance systems, our first step is to start with a process flow sheet. Figure 2 provides a simplified flow scheme, along with a definition of the system boundary to be considered in the analysis. From this drawing we can establish the basis for the calculations. 

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