Save energy, increase profitability & help to meet crc commitments by using the correct water pre-treatment for steam boiler feed
22 March 2011, News release from Wychwood Water Systems Limited
Industry is under pressure from:
·Increasing fuel costs
·Increasing cost of raw materials
In the effort to optimise energy usage and minimise emissions, one area of operation is often overlooked. This is the efficient treatment of water for steam generation.
Many industries and most boiler manufacturers are still only specifying simple water softening to pre-treat make up water to boiler feed systems for low pressure (<20bar) boilers. This is because they regard softening as adequate for their plant and it conforms to plant manufacturers and published guidelines such as the current EN12953-10 and the former BS2486. They are, of course, correct but this blinkered approach disregards the impact on energy usage of water.
In many parts of the UK, notably the South, E Midlands, E Yorkshire and parts of the N West, water supplies have levels of dissolved solids (300-500mg/l) that demand boiler blow-down rates of >5%, with consequent high energy losses. Water softening has no effect on this aspect of the water quality. However, by introducing a reverse osmosis plant downstream of the water softener, the dissolved solids are reduced by greater than 98%, enabling boiler blow-down to be reduced to less than 2%.
Reverse osmosis is a membrane-based process that removes over 98% of dissolved solids from a water supply. The membrane is so constructed that only water molecules pass through. The dissolved solids are expelled in the waste stream which either goes to drain, or can be reused for cooling or low-grade domestic purposes.
This dramatic reduction in boiler blow-down produced by the introduction of RO, saves so much energy going to drain that the cost of the RO plant can often be recovered in one to two years. Annual savings of £10,000-£50,000 in wasted energy are common and make a significant contribution to company profitability and reduction in emissions.
Whilst focussing on energy saving, the other benefits of RO treatment should not be overlooked. The use of pure water reduces system corrosion and hence, maintenance and also water treatment chemical costs.
The potential for the reduction of energy usage and CO2 emissions can easily be shown by a feasibility study when the data is entered in the boiler-house model developed by Wychwood Water Systems. A study can be arranged by contacting them on 01993 892211 or via www.wychwood-water.com
For further information please email Wychwood Water Systems Limited