Process Equipment Update
pumping energy required by S&Ts. Also, as there should be no fouling to increase the pressure drop over the heat exchangers, no extra pumping energy will be needed either. This means substantial energy savings.
Cleaner wastewater In Sweden, Örebro-based EON for many years has employed a policy of re-using purified wastewater. Wastewater is pumped from a pumping station in Skebäck up to two heating pumps at the Åbyverket CHP plant, where heat is recovered from the cleaned wastewater. Once that process is complete, the now cooled wastewater is pumped back via Skebäck and released into the river Svartån which flows into Lake Hjälmaren.
In 1998, EON also began supplying district cooling to
Örebro University Hospital, Örebro County Council and international paper and packaging company Mondi. As by definition the wastewater is not clean, it has to be purified. This meant that EON had to invest significant time and resources on site to clean customers’ heat exchangers. This was viewed as an unnecessary cost by both customers and the supplier. When EON was awarded the contract to supply district
cooling to central Örebro, the decision was taken to build a dedicated heat exchange station adjacent to the pumping station in Skebäck. Wastewater is now exchanged via a clean water system that is then distributed to the Åbyverket plant and sent on to district cooling customers. Tranter has supplied two GXD-205 gasketed plate heat
exchangers to exchange between purified wastewater and district cooling water. Total output is 18MW, 9MW per heat exchanger. Tranter’s plate heat exchangers are ideal for applications with close temperature approach. For this particular application, the heat exchangers were designed with one bar pressure drop. The relative high pressure drop maintains channel velocity and shear stress at a high level, thus reducing maintenance requirements - which is important for the wastewater. Tranter is involved in another heat exchange project at
Gävle Hamn, which has a strategically important location just 170 km from Stockholm and a catchment area that extends from Uppland and Dalarna northwards. Among other things, Gävle Hamn has, for some time, been supplying Arlanda airport with all its aviation fuel directly by train. One train replaces just over 30 tank trucks, which previously transported the fuel through Stockholm up
to Arlanda. Gävle Hamn has total storage capacity of 950 000m3
in around 140 tanks. The large oil and chemical
tanks in the port have previously been heated with fossil fuel in the form of oil. This relatively expensive method of heating is now being replaced with green district heating. The district heating specialist Palmat System chose
Tranter’s plate heat exchangers for the order it received from Gävle Rörteam, which is installing the district heating in Gävle Hamn. “Tranter represents cutting edge technical knowhow. Combined with their fast, reliable deliveries, this is a decisive competitive advantage in our customers’ eyes,” says Per-Arne Tönners of Palmat System in Stockholm. In other heat exchanger news, SWEP has developed
an SMO 254 steel version of its DP300 brazed plate heat exchanger (BPHE). The DP300 is already available in AISI 304 and AISI 304/316 steels, and the company says that this new high-molybdenum SMO 254 model gives customers even greater flexibility in their choice of materials for demanding applications. SMO 254 offers higher resistance against corrosion, for eample in cooling towers and ground source heat pumps where a high chloride content in the water can be an issue.
Flexible chillers The DP300 is an efficient and versatile true dual BPHE optimised for the environmentally preferred refrigerant R410A. The DP300 is a natural choice for flexible chillers and climate control applications, where its ability to offer full performance at both full- and half-load is a major advantage. In 2010 the company won the Frost & Sullivan Europe
Market Share Leadership Award in the BPHE market after capturing nearly 40 per cent of the market. SWEP has continually focused on improving the heat
transfer capability of its products. Enhanced material selection, such as the use of new types of stainless steel, has increased product resistance to corrosion. The company’s primary focus has been on three business segments: air conditioning, heating and refrigeration. It is also actively trying to convert the technology used in S&T exchangers - which are used widely in air conditioners - for use in BPHEs. It is looking to replace the traditional use of other PHEs in heating applications with appropriate brazed heat exchangers that are more effective, compact and reduce the overall size of the system. ■
Plotting the performance A
n air cooled heat exchanger test unit developed by Australian company Allied Heat Transfer can test and plot the performance of air cooled heat exchangers, allowing testing of existing units as well as refining the design of new units. Reductions in size, weight, noise and cost of air cooled heat exchangers is expected through the use of this equipment.
Recognising the capabilities of this piece of equipment, Australia’s national science agency
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CSIRO has placed it on the country’s technology partnerships equipment register. The objective of this register is to increase the capacity utilisation of this equipment for firms owning the equipment, while providing other firms with access to leading edge equipment or technology which would otherwise not be available. In a second development, Allied Heat
Transfer has commissioned a new cyclic fatigue test machine. “Obviously in a business that manufactures heat exchangers and pressure
vessels the testing of product is of critical importance,” says the company.
In addition to hydrostatic testing, the company also carries out the hot testing of units to imitate the operating conditions of the vessel, heat exchanger or oil cooler. Allied Heat Transfer also has the capability to carry out in-house destructive testing of representative samples when required, and regularly undertakes complete run tests of cooling systems by means of its hydraulic test bench, or by electric motors. ■
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