Process synthesis task integration

The task of process synthesis is to evaluate these schemes and select the best. The creative possibilities of design do not stop here. For example, these separations can be carried out by heat integration, by multiple-draw columns, or by use of processes other than distillation many other variations are possible. 

The optimization component of process integration drives the iterations between synthesis and analysis toward an optimal closure. In many cases, optimization is also used within the synthesis activities. For instance, in the targeting approach for synthesis, the various objectives are reconciled using optimization. In the structure-based synthesis approach, optimization is typically the main framework for formulating and solving the synthesis task. 

The phenomena-driven method for the process synthesis analyzes not the processing units, the so-called building blocks, but the phenomena that occur in those blocks. This method is based on opportunistic task identification and integration. It was applied to separation process synthesis, based on thermodynamic phenomena. It explored the relationship between the physicochemical properties, separation techniques, and conditions of operation. The number of alternatives for each separation task is reduced by systematically analyzing these relationships. Then, possible flowsheets are produced with a list of alternatives for the separation tasks. 

Since these are the building blocks of nearly all chemical processes, it is common to create flowsheets involving these basic operations as a flrst step in process synthesis. Then, in a task integration step, operations are combined where feasible. In the remainder of this section, before considering the steps in process synthesis, each of the basic operations is considered in some detail. 

The next synthesis step involves task integration, that is, the combination of operations into process units. In one task integration, shown in Figure 4.20, reactor effluent is quenched rapidly to 1,150 F, primarily to avoid the need for a costly high-temperature heat exchanger, and is sent to a feed/product heat exchanger. There, it is cooled as it heats the mixture of feed and recycle chemicals to 1,(X)0°F. The stream is cooled further to 100°F, the temperature of the flash separator. The liquid from the quench is the product of the reactor section, yet a portion of it is... 

The enterprise completes requirements analysis, functional analysis, and synthesis tasks to identify, define, and design architectures for life cycle processes. The enterprise performs tasks 6.1 through 6.4 to verify the design architecmre for each life cycle process product. The products associated with each life cycle process are bought or made and integrated with other products related to the process or other processes, in a timely manner, to support key technical events. 

Figure 1.1. Schematic representation of the conventional process for the synthesis of methyl acetate (left) and the highly task-integrated RD unit (right). Legend ROl reactor SOI splitter S02 extractive distillation SOS solvent recovery S04 MeOH recovery SOS extractor S06 azeotropic column S07,S09 flash columns SOS color column VOl decanter...

Patent databases are therefore integrated databases because facts, text, tables, graphics, and structures are combined. In patents that include chemical aspects (mostly synthesis or processing), the chemical compounds are often represented by Markush structures (see Chapter 2, Section 2.7.1). These generic structures cover many compound families in a very compact maimer. A Markush structure has a core structure diagram with specific atoms and with variable parts (R-groups), which are defined in a text caption. The retrieval of chemical compounds from Markush structures is a complicated task that is not yet solved completely satisfactorily. 

Hierarchical Approach is a simple but powerful methodology for the synthesis of process flowsheets. It consists of a top-down analysis organised as a clearly defined sequence of tasks grouped in levels. Each level solves a fundamental problem as, number of plants, input/output structure, reactor design and recycle structure, separation system, energy integration, environmental analysis, safety and hazard analysis, and plantwide control. At each level, systematic methods can be applied for the synthesis of subsystems, as chemical reaction, separations, or heat exchangers network. 

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