Heat recovery system design

Heat recovery system design in a paper mill Minimization of (1) steam needed in summer, (2) steam needed in winter, (3) area of heat exchangers and (4) cooling/heating needed for the effluent NIMBUS The process was simulated using BALAS. Hakanenetfl/. (2005 and 2006)... 

Waste heat recovery system design (provision of waste heat recovery boilers and economisers). 

Below the pinch, the system rejects heat and so is a net heat source. When a heat recovery system design does not have cross-pinch heat transfer, that is, from above to below the pinch, the design achieves the minimum hot and cold utility requirement under a given ATmin-... 

Smith, R., and Jones, P. S., The Optimal Design of Integrated Evaporation Systems, Heat Recovery Systems and CHP, 10 341, 1990. 

FSHR, see Flash steam and heat recovery systems FT boiler designs, development of 30... 

In this approach accident cases and design recommendations can be analysed level by level. In the database the knowledge of known processes is divided into categories of process, subprocess, system, subsystem, equipment and detail (Fig. 6). Process is an independent processing unit (e.g. hydrogenation unit). Subprocess is an independent part of a process such as reactor or separation section. System is an independent part of a subprocess such as a distillation column with its all auxiliary systems. Subsystem is a functional part of a system such as a reactor heat recovery system or a column overhead system including their control systems. Equipment is an unit operation or an unit process such as a heat exchanger, a reactor or a distillation column. Detail is an item in a pipe or a piece of equipment (e.g. a tray in a column, a control valve in a pipe). 

Preheater vibration. Air preheaters or any type of waste-heat recovery device designed for horizontal flow across vertical tubes, may be subject to vibration produced by the velocity of gas across the tube banks. The velocity produces a vortex-shedding wave pattern that could correspond to the natural harmonic frequency of the tube bank. If the natural harmonic frequency is reached, excessive vibration of the tubes will occur. Redesign of the internal baffle system by inserting dummy baffles can stop the vibration. 

Process Synthesis, an important research area within chemical process design, has triggered during the last three decades a significant amount of academic research work and industrial interest. Extensive reviews exist for the process synthesis area as well as for special classes of problems (e.g., separation systems, heat recovery systems) and for particular approaches (e.g., insights-based approach, optimization approach) applied to process synthesis problems. These are summarized in the following ... 

In a waste heat recovery system, we might reduce the heat transfer irreversibility by designing a heat recovery steam generator with a smaller stream-to-stream temperature difference, and/or reduce friction by designing a turbine with a higher efficiency. 

Direct heat recovery is the most efficient, with up to 85% of the heat recoverable. It is usually applied in continuous deodorizers, whereas the indirect heat recovery system is used preferentially in semi-continuous deodorizers with frequent feedstock changes. The efficiency of the indirect heat recovery depends largely on the type and design of the system (Figure 12). 

Sulfur can also precipitate as ammonium sulfate on downstream heat transfer surfaces. Any new heat recovery system must be designed to deal with this precipitation. Existing systems must be checked to make sure they can be cleaned without disrupting the process. 

Finally, we discuss an example of designing a heat recovery system for the process water system of a paper mill (see Fig. 6.5). The problem involving four objective functions has been described and solved in Hakanen et al. (2005, 2006). We consider a virtual fine paper mill operating in a climate t3q)ical to northern latitudes, where ambient temperature varies according to the season. 

If the heat management was designed only according to winter conditions, the sizing of the heat recovery system would be too large resulting in... 

Design, appHcation, and performance of heat recovery systems Advanced materials of construction Flue gas characterization Integrated computational design tools Design tool characteristics Technology transfer... 

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