The following are some installation notes and photo’s on a recent project for installing a disc shaped stack balloon inside of the HRSG exhaust stack at the CEMS platform level on a 7FA Gas Turbine with HRSG:
The plant has two GE Frame 7FA Gas Turbines. The exhaust stack is 17’6” diameter x 125’0” high. The CEMS platform level is at a 60’ elevation.
An access door was installed about half way up the stack which measures 2’6” x 2’6”. Note the 2” diameter stainless steel support rod above the door opening which spans the 17’6” diameter stack. The support rod was installed to permanently stay in place inside the stack after the balloon is removed. This installation location was chosen as it is below the existing CEMS equipment.
Eight oval rings are attached to the support rod.
Nylon rope is attached between the stack balloon grab handles which are sewn into the top of the balloon and also to the carabineers.
The balloon is now hanging inside the stack ready for inflation.
As the balloon starts to inflate, it expands off the ID of the stack near the access door and moves outward along the support rod. Inflation time is less than 5 minutes. Total removal time from the stack takes about 5-7 minutes.
The 120V high pressure blower must remain on at all times to keep the balloon fully inflated. Note that the inflation tube connection point on this application is sewn into the side of the balloon, so about 80% of the thickness of the balloon remains below the access door. The balloon can be installed inside the stack on a slight angle to permit runoff to the floor drains. If snow accumulates on the stack balloon, it will quickly melt due to the residual heat rising from below. Even though the blower is rated for outside use, it was eventually moved inside the HRSG building.
Copyright 2010 by G.R. Werth & Associates, Inc. - All rights reserved
Duct Balloon
Inflatable Isolation Barriers
