Gas Moving Vacuum Service

Liquid-piston vacuum pump down to 12 kPa absolute 0.01 to 1000 kg/h air see also Section 6.37. 

Rotary sUding vane vacuum pump down to 4 kPa abs. 0.01 to 300 kg/h  

For most steam ejector applications, direct contact condensers between stages were frequently used. For vacuum steam stripping, use shell and tube condensers with refrigerant at -8 to -12 °C upstream of the booster ejector with interstage dry condensers plus a liquid ring vacuum pump. 

Assume the discharge pressure to atmosphere after the last stage = average barometric pressure +7 kPa. Assume motive steam = minimum steam pressure in header less 5-10%. Pressure drop on shell side of surface condenser usually 5 % of absolute design operating pressure. 

Related topic Section 3.9 for interstage direct contact G-L condensers, although current practice is to use surface shell and tube condensers (H). 

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In this section, we consider gas moving equipment for pressure service and then for vacuum liquid moving equipment. Then, two-phase flow is considered in Section 16.11.2.4. Hydraulic conveying of solids is discussed in Section 16.11.2.5. Conveying solids is considered in Section 16.11.2.6, while Sections 16.11.2.7 and 16.11.2.8 address piping and steam. 

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