Boiler and cooling water treatment

Case studies

1. Chocolate Manufacturer

The existing boiler treatment plant was at the end of its useful life and needed replacing. The client wanted to avoid acid on site if possible. A RO scheme was designed and costed which together with the boiler chemical and blowdown savings was cheaper than the conventional plant. Full tender enquiry , evaluation and project management was undertaken.


2. Power Station

The Client was using borehole water with a high TDS. The conventional demineralisation plant was using high volumes of chemicals for regeneration. A scheme was evaluated to install an RO plant in front of the demineralisation plant which showed an excellent payback of less than 2 years. Full tender enquiry , evaluation and project management was undertaken.


3. Alumina Producer

The client was producing 350 m3/hr of demineralised water for steam raising but the plant was overloaded and was always in regeneration. A feasibility study was undertaken as to how best to uprate the plant. Various options such as RO etc were evaluated. The best option was to convert the existing three streams to packed bed design and install a fourth stream. Vale Water produced all of the vessel designs, pipework drawings , schedules and electrical designs including programming changes and software. The client used the drawings etc to purchase the equipment and installed the plant themselves under the management of Vale Water.


4. Power Station

One of the largest power stations in the UK had experienced some condenser corrosion problems. An investigation into the water quality and treatment showed the corrosion was “tubercule“ formation caused by generalised corrosion. The water was being treated with acid to reduce corrosion and generally the LSI was maintained positive. However the cooling water was drawn from an estuary with fluctuating salt levels and LSI variations were inevitable. Other treatment regimes were investigated but discounted as being too expensive for the large volume of cooling water. Tighter controls on pH and LSI were implemented with corrosion coupon racks being inserted and regularly monitored. Finally changed pipework metallurgy was proposed for critical and vulnerable parts of the process.

5. Pigment Manufacturer

A major UK pigment manufacturer experienced several large compressor failures due to corrosion on the cooling water side. An assesment of the corrosion revealed this to be generalised corrosion due to poor LSI and inhibitor control over a period of time. The cooling tower in question was remote from a power supply so dosing of treatment chemicals were carried out by hand twice a week. It was clear that the varying load of the compressor made this type of chemical addition impractical. The chemicals being used were correctly selected but the application and control were not. Modifications to the sytem were made to give automatic dosing of chemicals and automatic blowdown control.