Compressors centrifugal, surge control

Boyce, Meherwan P., et al. Practical Aspects of Centrifugal Compressor Surge, and Surge Control, Proceedings of the 12th Turbomachinery S ni-posium, Purdue University, West Lafayette, IN, 1983, pp. 147-173. 

Brown, Royce N., An Experimental Investigation of a Pneumatic Closcrt Loop Anti-Surge Control for Centrifugal and Axial Flow Compressors Master s Thesis, University of Wisconsin, Madison, Wisconsin, 1966,... 

Figure 12-61D. Centrifugal compressor surge control schematic diagram shows instrumentation required when primary flow-measuring device is located in centrifugal compressor discharge line. Symbols T = temperature P = pressure A = differential across compressor outlet to inlet. See Reference 89 for a detailed discussion. (Used by permission White, M. H. Chemical Engineering, p. 54, Dec. 25,1972. McGraw-Hill, Inc. All rights reserved.)...

Figure 3.23. Control of centrifugal compressors with turbine or motor drives, (a) Pressure control with turbine or motor drives, (b) Flow control with turbine or motor drives. SC is a servomechanism that adjusts the guide vanes in the suction of the compressor, (c) Surge and pressure control with either turbine or motor drive. The bypass valve opens only when the flow reaches the minimum calculated for surge protection.

C. Protective Instrumentation. Some compressors require an extensive list of instrumentation to avoid unsafe situations and mechanical damage to the compressors themselves. This is particularly true in the case of centrifugal machinery. A previous section discussed the most prominent example, the surge control system. Other likely sources of damage of the rotating machinery are vibration and the loss of lubrication. 

Baker, D, F., "Surge Control for Multistage Centrifugal Compressors", Chemical Engi-... 

As mentioned previously, a large centrifugal compressor with a gas turbine as a driver is typically a multi-million dollar investment. A dedicated computer control system is usually employed to monitor multiple operating parameters, and that is specifically designed for the purpose. Such a control system is shown in Figure 7.27. The control of a centrifugal compressor involves the control of capacity, the prevention of surge and the protection of equipment. 

Magliozzi, T. L., Control System Prevents Surging in Centrifugal Flow Compressors, Chem. Eng., p.l39. May 8, (1967). 

Large centrifugal compressors are usually so expensive that it is generally not economically feasible to specify spares.29 To put two of these in parallel can result in surging, due to their flat operating characteristics, unless a control scheme such as that given in reference 35 is specified. 

Fig. 14.3 Centrifugal compressor installation. Note that the designer has chosen to locate the connecting piperack on a level above the compressor this provides the facility to anchor the piping loads caused by thermal expansion, and also maximizes access to the compressor (while minimizing the elevation). Note also the bypass control valve for surge protection...

---