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View Full Version : Design layout of glycol distribution system



andrewmj1
03-20-2009, 10:21 PM
Hi
Our brewery is currently in the process of installing a new chiller unit to do our total cooling load. The unit is a 200kW unit, which has been sized (external company) for our 2.6million lt size. The current refigeration system joins on to our glycol supply network via a glycol buffer tank and 2 process centrifugal pumps supply glycol to 20tanks, a flash pastueriser and a water chiller through one supply that affectively runs past each tank dropping down to the tank inlet through a controlled solenoid from a tank farm control, and then back to a common return line. All lines are 2" Stainless Steel tube, and the longest run would be 80metres I guess. The pumps run constantly regardless of demand, with no VSD setup for constant pressure supply.
I wondering during the process of installing the new chiller unit whether we look at how our glycol is distributed. Originally I was planning on installing 1 new supply and return pump/line dedicated just for the pasteuriser and splitting the spare pump outlined above off the main circuit and installing a third circuit to cover the brewhouse, with all three pumps running off pressure switches to start and stop them. I felt the beauty of this sytem ensured that each location received the correct flowrate needed to run (i.e. pasteuriser was 3lt/sec glycol). After chatting with another consultant he suggested one common ring main around the entire process and put booster pumps off this circuit to each process (like the pasteuriser) to ensure the correct flowrate. He also suggested using a VSD controlled primary pump to control to pressure. This idea sounds good, but wondered with a 2" current supply return system whether this would provide enough flow to all the processes, and also whether there was really any real gains. Seemed expensive. Loved to hear what people think .
The other question that I had was regarding to head calcs for pumps. Our current process pump sits next to a 2000lt buffer tank with both of these sitting on a platform 3m above the floor. The tanks (FVs) that the pump pumps to stand about 7m in height above the ground floor. The new plan works on removing the platform and having the buffer tank/process pump sitting on the floor. The return line returns back in the top of the tank. Will this add an extra 3m of head on to my total head of this pump? Currently this pump is almost at its limit so 3metres more of head will result in the pump not handling it nor giving me the correct flowrate needed.
Sorry for the long thread, but can't seem to get a clear opinion on the above problems. Appreciate anyones input.