Dangerous Noise Level Problem Solved in Industrial Back-Pressure Turbine

For many years, a turbine bypass valve and a desuperheater valve that supply process steam to a large, Southeastern, multi-product chemical-process plant have vibrated severely and produced noise levels in excess of 120 dBA, threatening physical danger to operating personnel.

In addition to the existing turbine bypass valve design itself, system configuration was also a contributor to the problem. The variable-area, probe desuperheater valve provided for single-stage pressure reduction through an integral sparger: this sparger was necessitated by the drastic steam expansion through the 12 inch by 24 inch (300 millimeter by 600 millimeter) blanked-off tee into which the pressure-reducing sparger extended.

This 12 inch by 24 inch (300 millimeter by 600 millimeter) measurement required valve inlet/outlet configuration, and with the use of multi-stage, tortuous-path DRAG® technology, the replacement CCI valve reduces steam pressure from 1260 psig to 440 psig (8.7 Mpa to three Mpa). The steam expansion problem is therefore handled through a multi-port, single-purpose sparger that functions only as a steam flow diffuser.

As for the replacement desuperheater water flow injector also provided by CCI, instead of being located downstream of the safety-relief valves, it is now located in the blanked-off tee, directly beneath the pressure-reducing DRAG® valve’s integral diffuser. This alteration in configuration assures that the resulting desuperheated process steam conditions are well within the rating of the safety-relief valves.

With the help of CCI technology, noise levels have been reduced to a point well below acceptable industry standards. In addition, a long-standing process system low-flow requirement of 30,000 pounds/hour (13,600 kilograms/hour) that the old turbine-bypass valve design was unable to meet can now be attained without difficulty.

Published in SOLUTIONS Summer 2000