Compressors centrifugal flow

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

The unit has virtually the same flow sheet (see Fig. 2) as that of methanol carbonylation to acetic acid (qv). Any water present in the methyl acetate feed is destroyed by recycle anhydride. Water impairs the catalyst. Carbonylation occurs in a sparged reactor, fitted with baffles to diminish entrainment of the catalyst-rich Hquid. Carbon monoxide is introduced at about 15—18 MPa from centrifugal, multistage compressors. Gaseous dimethyl ether from the reactor is recycled with the CO and occasional injections of methyl iodide and methyl acetate may be introduced. Near the end of the life of a catalyst charge, additional rhodium chloride, with or without a ligand, can be put into the system to increase anhydride production based on net noble metal introduced. The reaction is exothermic, thus no heat need be added and surplus heat can be recovered as low pressure steam. 

To be able to decide which type of compressor would best fit the job, we should first divide the compressors into three main categories positive displacement, centrifugaf and axial flow In general terms, positive displacement compressors are used for high pressure and low flow characteristics centrifugal compressors are used for medium to high pressure dehvery and medium flow and axial flow compressors are low pressure and high flow... 

Continuous-flow compressors. a. Centrifugal compressors h. Axial flow compressors... 

For ease of illustration we will consider the characteristics and behaviour of a centrifugal pump which is similar in behaviour to radial/axial flow fans and centrifugal/screw compressors. Figure 63 shows the mechanical connection of a flow valve to control the output of the pump or the discharge of the fluid through the throttle of the valve. Figure 6.39 illustrates the characteristics of the pump ... 

Figure 3-10 shows a similar performance map for an axial-flow compressor. Note the smaller operational flow range for the axial-flow compressor as compared to the centrifugal compressor. Figure 3-11 shows a typical compressor map presented from a slightly different viewpoint. On this map. 

The turboprop engine has a power turbine instead of the nozzle as seen in Figure 4-2. The power turbine drives the propeller. The unit shown schematically is a two-shaft unit, this enables the speed of the propeller to be better controlled, as the gasifier turbine can then operate at a nearly constant speed. Similar engines are used in helicopter drive applications and many have axial flow compressors with a last stage as a centrifugal compressor as shown in Figure 1-14. 

Dallenback F., The Aerodynamic Design and Performance of Centrifugal and Mixed-Flow Compressors, SAE International Congress, January 1961. 

Figure 1. Approximate ranges of application for reciprocating, centrifugal, and axial-flow compressors.

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,... 

Figures 12-46 illustrates the key styles of wheels for use on the rotating shafts of multistage centrifugal, single-stage compressors and fans, and axial flow compressors (to he discussed later in this chapter). The flow-handling capability of a specific impeller geometry is descrihed hy the flow coefficient, ...

Classifications 477. Standard Units 481. General Calculations 481. Reciprocating Compressors 484. Rotarv Compressors 487. Centrifugal Compiessors 493. Axial-Flow Compressors 494. 

Figure 3.6. Approximate polytropic efficiencies centrifugal and axial-flow compressors...

Axial flow compressors have polytropic efficiencies up to 10% higher than centrifugal compressors for the same pressure ratio. A reasonable estimate is for the efficiency to be 5% higher than that of the corresponding centrifugal machine (i.e. multiply the estimate from Equation 13.18 by 1.05). 

In turbomachineiy the centrifugal flow and the axial-flow compressors are the ones used for compressing gases. Positive-displacement compressors such as reciprocating, gear-type, or lobe-type are widely used in the industry for many other applications such as slurry pumping. 

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