Water critical pressure

Water Critical pressure and temperature values of water are 220 bar and 373.14 °C. Steam is a valuable heating agent below 200 °C, where the saturation pressure is about 24 bar. Superheated steam can be used to enlarge the temperature range. Liquid water is excellent for cooling, but also for heating at mild temperatures below 100 °C. For higher temperatures thermal fluids are more suitable. 

Water critical pressure—22.064 MPa and critical temperature—373.95°C (NIST REFPROP, 2010). D2O critical pressure—21.671 MPa and critical temperature—370.7°C (NIST REFPROP, 2010). 

Certain boilers employ forced circulation, whereby a pump helps impart the circulation through the downcomer lines to the waterwaH header, particularly to improve or control circulation at low loads. Forced-circulation pumps are also required in high pressure and supercritical pressure boilers, because once the pressure within a boiler approaches the critical pressure, 22.1 MPa (3208 psia), the densities of the water and steam become similar, limiting or eliminating the potential for natural circulation. 

Critical Pressure Ratios For Liquids Other Than Water... 

Pb Barometric pressure, mmHg Pc Critical pressure of water, 166,818mmHg Pd Saturation pressure of w-ater at the dry-bulb temperature, mm Fig... 

In order to avoid the need to measure velocity head, the loop piping must be sized to have a velocity pressure less than 5% of the static pressure. Flow conditions at the required overload capacity should be checked for critical pressure drop to ensure that valves are adequately sized. For ease of control, the loop gas cooler is usually placed downstream of the discharge throttle valve. Care should be taken to check that choke flow will not occur in the cooler tubes. Another cause of concern is cooler heat capacity and/or cooling water approach temperature. A check of these items, especially with regard to expected ambient condi-... 

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