Upgrade to Condensate Filter Elements Saves Power Plant $110,000/Year

Overview

At a four-unit power plant in southern Indiana, units 2 and 3 are supercritical boilers with original-equipment two vessel condensate filter demineralizer systems. Unit 4 is a supercritical boiler with a powdered resin precoat condensate filter demineralizer system.

Units 2 and 3 have traditionally been operated using string wound filter elements with powered resin precoat and cellulose fiber overlay which acts as a filtration aid and protects the string wound elements from prematurely fouling. Unit 4 uses the same precoat material with stainless steel spiral wound elements.

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The Problem

The Station was precoating every 30 days. The cost for one precoat on Unit 2 is approximately $1900 per vessel (resin acquisition cost only). The station’s goal was to reduce resin costs while maintaining required condensate chemistry.

The station precoated monthly because the string-wound elements being used tended to foul with particulate contamination and embedded powdered resin due to the filters’ depth filtration characteristics. In addition, the strings would loosen and stretch as a result of forward and backflush flows.

The plant needed to find a way to optimize their condensate demineralizer system in order to reduce system operating costs.

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The Solution

In October 2002, the station upgraded the Unit 2 polisher with the installation of Pall Corporation’s meltblown Hydro-Guard® CoLD® elements. The new Hydro-Guard CoLD elements are comprised of 100% polypropylene meltblown reverse depth graded pore structure filter media, with a 2.25" outside diameter (OD), compared with 2" OD on the old string elements. This slight increase in OD provided a 14% increase in precoatable surface area, which lowered the vessel flux rates significantly. These features improved operating performance due to better backflush ability, more uniform precoat application, absolute filtration matrix, and precise element permeability.

The Station has replaced the Unit 3 string-wound elements with Pall Corporation’s Hydro-Guard CoLD elements in March 2004, and is currently experiencing similar cost savings. The station has recently initiated a project to upgrade the old vessels with Hydro-Guard CoLD elements.

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The Benefits

The station is now precoating every 60 days, versus every 30 days, cutting precoat costs in half.
By reducing precoat frequency from 12 precoats per year to 6 precoats per year, the station has saved $50,000 per year on Units 2 and 3 resin costs alone.
The system needs less oversight and requires less manpower, allowing staff to concentrate efforts on other key plant issues.

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