Improved sustainability in the power market

Paul Boughton
Today's power market is characterised by extremes. Lots of energy is required, resources are becoming scarce and more expensive and on that top of that waste regulations are becoming increasingly stricter. Femke Schaefer reports.

Sustainability has only recently turned into something more than just a buzz-word in the power market. Top managers of companies such as Shell and DSM are rated based on their sustainability performance. And the European Union has set regulations on CO2 emissions making the old fashioned way of waste management, landfill, no longer applicable and additionally are forcing countries and companies to look for more sustainable and environmentally friendly ways of waste management. In this context every issue involves large amounts of time and money.

In the power market these kinds of challenges touch process related heat transfer and fluid flow problems but also sustainability related issues such as noise restrictions and energy conservation. These four examples emphasise potentials for these kinds of environmental challenges.

District heating

An example of achieved sustainability in a district-heating facility: A new power station requires an air-cooled vacuum condenser and a district-heating heat exchanger, both taking exhaust steam from the same turbine.

The control of capacity and pressure is difficult, requiring a complicated system with steam butterfly control valves and split condensate packages.

Careful analyses and a balanced re-design of the complete unit (piping and instrumentation design) leads to a system with fewer components (fewer heat exchangers, condensate tanks and pumps and auxiliaries), less maintenance (costs) and much lower power consumption, while being easier to operate.

Heat transfer

An example of improved heat transfer and fluid flow: Especially the design and mechanics of dry-cooling towers and A-frame condensers faces challenges in heat transfer and fluid flow. Why? When this kind of equipment is used in a closed cycle the design can meet high environmental requirements. Such as? In the integration approximately 20 per cent lower electric power is consumed.

In that case a supplier is needed which is capable of designing and supplying complete and integrated cooling systems including steam ducting, condensate tanks, valves and other auxiliary equipment. That is the improvement (Fig.1).

Another example of sustainability achieved through better energy efficiency: As a result of a recent change in the process, a client now has an excess of steam. They wish to generate as much electricity as possible with a well yielding investment.

Parasitic load

Apart from the amount of extra electric power generated it is also important to pay close attention to the parasitic load of this new installation and possible improvements in the whole cycle.

The solution can be straight forward. By using a custom designed turbine and a high efficiency air-cooled condenser in an optimised process design, resulting in an optimized system with maximum level of realised electric power from a fixed (existing) steam-flow.

The high efficiency air-cooled condenser is realised using the ultra high efficiency Whizz-Wheel fans recently introduced into the market by Bronswerk Heat Transfer.

These fans in combination with optimal designed equipment allow an increased airflow, reduced energy consumption with reduced operational cost (Fig.2).

Ultra low noise

The Whizz-Wheel ultra-low noise and ultra high efficiency fans were specially developed using the most sophisticated airflow simulation software, with the goal of decreasing the acoustic load on the surroundings. As a bonus they achieved enormous energy savings of more than 50 per cent, translating directly into large CO2 emission reductions.

On top of that the Whizz-Wheel weights 50 per cent less compared to conventional fan systems. This means a tremendous basic energy saving in terms of sustainability (Fig.3).

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Femke Schaefer is with Bronswerk Heat Transfer BV, Nijkerk, The Netherlands.

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