HOT|COOL NO. 3/2017 - "North America"


SILHORKO-EUROWATER has supplied a new plant for producing make-up water for the district heating grid in Aalborg, Denmark. The plant is a vital part of Aalborg’s maintenance plan, allowing the main make-up production facility to be shut down on a regular basis for maintenance.

By Jorn Urup Nielsen, Group Sales Director, SILHORKO-EUROWATER A/S

untreated water through the network as well as interruption of supply to the customers of the district heating company. Correct water treatment strongly influences lifecycles and maintenance requirements for key assets such as pipes, fittings, boilers, heat exchangers etc. The recommendations apply to all water-born district heating systems irrespective of operating temperature. In other words, the recommendations are all about good asset management. Several typical operational problems in district heating systems origin from (lack of) water quality and can be addressed by changing the water quality: • Oxygen corrosion in expansion vessels, holding tanks, pipe systems, and in radiators. • Calcium carbonate precipitations on heating surfaces, in boilers and heat exchangers. • Crevice corrosion at assembly points in armatures, radiators, holding tanks and general surface corrosion. • Sludge and deposits on meters, adjustment devices, radiators, holding tanks, and in general in places with low flow. • Stress corrosion of stainless steel due to high chloride content. • Sulphide attack on plant parts of copper and copper alloys. • Circulation, flow issues due to air discharge in boilers and heat exchangers. • Microbial corrosion and biofilm.

Denmark is considered the leading district heating market when it comes to innovation and practical experience with modern district heating. For this reason, recommendations issued by the Danish District Heating Association are typically received with much interest from other countries, in order to learn “Best Practice” based on findings from the close to 400 district heating companies in Denmark. Water treatment plants can be designed partly based on water analysis for the water used as inlet for the plant, partly based on information on which water quality it needs to deliver at the outlet. Design parameters include opportunities for water and energy savings, minimum use of chemicals, minimum floor space footprint for the plant, trouble-free installation and operation, fast/safe and reliable commissioning of plants etc. It means we often supply frame mounted installations combining several water treatment technologies into one compact plant complete with PLC’s. Recently, the Danish District Heating Association published its recommendations for correct water treatment for district heating with a view to prevent corrosion of pipes etc. – which could cause water leakages (loss of water and energy), intake of

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