Using the Strengite Process to Clean a Heavily Fouled Glycol System at The British Museum
The condense chilled water system at the British Museum was treated with antifreeze to protect the system from freezing damage. Regretably the antifreeze had become acidified by bacteria and became highly corrosive. Acidified glycols are well known for having corrosion rates up to nearly 1000 times greater than normal. Severe damage to pipework can occur in short time periods. In most regions, antifreeze is not allowed to be discharged to drain. Expensive tankering way of the system water to disposal is required. The lost glycol has to be replaced at the end of the cleaning. This is both costly and has a large carbon foot print of three kilos of CO2 released per kilo of antifreeze added. Cleaning of corroded closed loops treated with antifreeze is more costly and difficult than cleaning standard closed loop systems.
A Low Oxygen Corrosive Environment
The British Museum condensor system contained 10.3% monoethylene glycol. The system volume was 10,400 litres. The system pH varied between 5.6 to 6.1 depending upon where sampled. The system was left under acidic conditions for approximately one year. Severe corrosion had occurred in spite of a low oxygen enviroment being present. Samples taken from the system would initially appear clear with a slight black tinge but when left for a few hours, the presence of oxygen in the air changed the oxidization state of the dissolved iron and the samples turned an opaque orange/brown colour. The magority of the pipework was made of iron and steel.
Cleaning Up the System Without Discharge or loss of Glycol
The Strengite Process was used to clean this system without discharge. The antifreeze within the system was not lost. The cleaned up system water was pH adjusted to between pH 8.1 and had a final iron level of below 0.2 ppm. The final copper level was below 0.2 ppm.
It is possible to directly calculate the amount of corrosion removed by a Strengite Process clean. Approximately 48 kg of rusts were removed by this cleaning. This equates to an iron level of 3345 ppm iron released during the clean. Traditional cleaning methods rarely go above 1000 ppm iron and would have required three cleanings to achieve this result. The Strengite Process achieved this in a single clean. Approximately 312,000 litres of water consumption and pollution were avoided.
The entire cleaning and removal of contaminants took aproximately 10 days.
The Strengite Process successfully recovered 1071 kg of antifreeze and prevented 3.2 tons of CO2 emissions. Additionally it avoided a large tanker based disposal cost. It avoided consuming and pollution 312,000 litres of water. The Strengite Process clean removed many times more rust than alternative cleaning methods. It suppressed iron solubility post cleaning even when rust deposits still remained within the system.
The Strengite Process is a better way to clean closed loop systems.
The Strengite Process is a patented process. The technology, equipment and products for the Strengite Process are only available to licenced and trained water treatment specialists who operate to a high standard and skill level.