Practical Process Engineering

https://bit.ly/2QHAcvO Hydrocarbon Processing & Gas Processing

4th Volume- 2019

3rd Volume- 2016

2nd Volume- Third Edition- 2014

1st Volume- Third Edition- 2008

Important notes from #Fisher for #DESUPERHEATER_STATION_DESIGN 1- Hot temperature water is much better for desuperheating than cold as it has lower latent heat, lower surface tesion and viscosity. Generally speaking, water above 93 C (200 F) will provide a vaporization benefit at the expence of greater water consumption (1~1.5% for every 28 C (50 F) increase over 93 C). 2- The amount of residual superheat is an indicator of how rapidly the water will vaporize to steam. Residual greater than 11 C (20F) indicates the process can be expected to be completed in a reduced length. 3- The evaporation and mixing time will take longer for the large diameter pipes. Larger pipe sizes have larger flow areas that must be exposed to the desuperheating water. 4- If the water is injected within three pipe diameters of a "Pressure Reducing Valve", the turbulance coming out of the PRV aides in the mixing, which can in turn reduce pipe length requirements. 5- It is important to not control too close to the saturation temperature. Temperature controller setpoint should not be less than 6 C (10 F) above the steam saturation point. 6- The spraywater pressure entering the desuperheater or spraywater control valve should exceed the outlet steam pressure by at least 150 psid (Pound Per Square Inch Differential) to have completet atomization . The bset pressure difference is between 500~1000 psid at th expense of some limitations applying to the control valve type. Higher psid increases cavitation potential. 7- Install a strainer just upstream of the spraywater control valve. It should be sized based on the smallest opening which is usually located in the spray nozzle (generally in the 40-100 mesh range). 8- Avoid multiple bends/ elbows immediately before and after the valve. 9- Noise levels that exceed 110 dba, as predicted with standard weight pipe with no insulation, may cause structural fatigue leading to associated failures. Noise abatement trims, insulation, and downstream silencers can be used to reduce transmitted noise. 10- When piping several valves on branches from a common header, locate them at different distances from the header to avoid pressure oscillations caused by resonance phenomena. 11- Piping layout should avoid projections, branches, T‐connections, manifolds, or short radius elbows prior to previously discussed recommended straight pipe requirement. 12- Use of T‐connection instead of long radius elbow for the first directional change is not recommended due to the potential for increasing equipment vibration levels. 13- The steam conditioning valve and its associated spraywater control valve should be insulated with appropriate materials that will address both noise and thermal reduction requirements. The entire valve should be insulated, including the valve's bonnet surface that faces the actuator.

#TSL #Temperature_Sensor_Length Fisher recommends this TSL for general estimation: A) For applications with less than 15% spray water: TSL (length)= 0.2 * Maximum Outlet Steam Velocity B)For application with more than 15% spray water: TSL(length)= 0.3* Maximum Outlet Steam Velocity Please note that: %spray water= (water flowrate/ steam flowrate)* 100

#SPL #Straight_Pipe_Length Fisher recommends this SPL: SPL(length)= 0.1 * Maximum Outlet Steam Velocity(length/s)