Process integration heat pumps

Heat Integration Integrate heat transfer between hot and cold process streams Heat pumps Cogeneration... 

Figure 6.38 Integration of heat pumps with the process.

Unfortunately, the overall design problem is even more complex in practice. Spare driving forces in the process could be exploited equally well to allow the use of moderate utilities or the integration of heat engines, heat pumps, etc. in preference to distillation integration. 

The use of the pinch technology method in the design of heat exchanger networks has been outlined in Sections 3.17.1 to 3.17.6. The method can also be applied to the integration of other process units such as, separation column, reactors, compressors and expanders, boilers and heat pumps. The wider applications of pinch technology are discussed in the Institution of Chemical Engineers Guide, IChemE (1994) and by Linnhoff et al. (1983), and Townsend and Linnhoff (1982), (1983), (1993). 

There are two fundamental ways in which a heat pump can be integrated with the process across and not across the pinch14. Integration not across (above) the pinch is illustrated in Figure 16.37a. This arrangement imports W... 

Figure 16.37 Integration of heat pump with the process.

Figure 16.38 shows a heat pump appropriately integrated against a process. Figure 16.38a shows the overall balance. Figure 16.38b illustrates how the grand composite curve can be used to size the heat pump. How the heat pump performs determines its coefficient of performance. The coefficient of performance for a heat pump can generally be defined as the useful energy delivered to the process divided by the power expended to produce this useful energy. From Figure 16.38a ...

For heat pumping to be economic on a stand-alone basis, it must operate across a small temperature difference, which for distillation means close boiling mixtures. In addition, the use of the scheme is only going to make sense if the column is constrained to operate either on a stand-alone basis or at a pressure that would mean it would be across the pinch. Otherwise, heat integration with the process might be a much better option. Vapor recompression schemes for distillation therefore only make sense for the distillation of close boiling mixtures in constrained situations3. 

In addition to the development of new products with previously unavailable property combinations, the task of making the process more efficient is important, particularly in this day and age. The cost factor energy can still be reduced if, for example, the heat of polymerization can be better utilized. It has been suggested that heat pumps be used for this purpose and the energy recovered be employed for the devolatilization step (38). In the same paper the author also suggests the integration in one factory of the monomer/polymer and end product fabrication, the latter since the polymer is already available in the molten state. 

The combined production of heat and power in the flame of the same process is called cogeneration. This technique offers opportunities for very efficient energy integration. The generated mechanical work or electricity can be used to drive compressors or heat pumps, while the heat can be used as hot utility. Two major applications will be examined. 

Becker H, Marechal F, VuiUertnoz A, editors. Process integration and opportunity for heat pumps in industrial processes. Proceedings of EGOS 2009, the 22nd International Conference on Efficiency, Costs, Optimization, Simulation and Environmental Impact of Energy Systems 2009. (Parana, Brazil). 

Figure 6.1 Setup of a microreaction screening plant with integrated spectroscopic process analysis. The total microreaction setup can be flooded with a cooling or heating agent to adjust the desired process temperature. External pumps control flow rate and stoichiometryofthe...

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