Achieving quick ‘green’ wins from a steam system
As businesses rise to an increasingly complex set of energy and sustainability challenges, the need for sustainable solutions is greater than ever. Michael Hyde offers some insight into what can be done today to optimize steam systems.
Steam is an inherently natural medium. On its simplest level it is just the boiling of water, but with some totally unique properties. This is why it has been adopted as the preferred method of delivering thermal energy and motive energy across many industry sectors. A steam system can distribute around a building, or a process and can be done safe due to it just being water in its gaseous state, but with far higher thermal qualities.
As technology advances – through methods of green generation and thermal battery technology – steam will continue to become increasingly sustainable, to capitalize on renewable sources and optimized through digital advances. Steam provides a long and well-proven source of energy used across a wide range of applications and sectors.
The starting point for a steam system
There should be ongoing activities to look at how steam systems are currently operating and to make sure they are effective and efficient. Even when considering significant plant changes to address sustainability and energy, it is important to understand the starting point for your plant, the base-line energy consumption. Optimizing the efficiency of a steam system could be easier than expected. There are several ways in which optimization can be realized:
- Achieving demand reduction through improved plant management and preventative maintenance.
- Adopting steam system best practice to minimize plant consumption.
- Addressing areas of energy loss by implementing heat recovery systems and techniques.
- Maintaining steam quality to maximize process effectiveness.
- Measurement of utilities to trend and optimize performance.
But, where to start? A good first step is to take a look at the existing steam trap population, which is the most important link in the steam and condensate loop. We know that removing condensate and air from a steam system is essential whilst returning condensate to the boiler house maximizes use of energy. A healthy steam trap population allows condensate to be removed from the steam system effectively meaning it can be re-used. Effective steam trapping through a management program is a critical factor to ensuring a healthy steam trap population and can greatly contribute to lowering energy consumption, maintaining product quality and increasing productivity.
Going in the right direction
From trapping stations to specific trap devices, steam traps are considered to be one of the most effective resource-saving measures, so how can an effective steam trap management program help? There are four key benefits to consider:
Health and safety: As with any utility in the plant, such as hot water or electricity, a steam system must be well managed to ensure safe operation. Correctly designed and operating steam trapping allows condensate to be effectively removed from the system, eliminating any potentially hazardous situations, such as pipe or component failure.
Productivity and process improvement: Correctly functioning steam traps allow the steam system to deliver the thermal energy required for process applications to operate efficiently. Condensate in the steam supply can affect the operation of applications, causing issues such as slow start up times and poor heat transfer. Removing the condensate from the system allows the steam to perform its task effectively within the process.
Sustainable energy savings and reduced carbon emissions: Condensate typically contains around 25% of the usable energy of the steam from which it came. Returning this to the boiler feed tank can save thousands of pounds per year in energy alone and reduces the requirement for fresh replacement water, whilst minimizing the need for costly chemicals to treat raw water.
Condensate removed from the steam system and returned to the feed tank also reduces the need for boiler blowdown, which is used to regulate the concentration of dissolved solids in the boiler. This therefore reduces the energy lost from the boiler during the blowdown process – all contributing towards your overall sustainability goals.
Lower cost of ownership: Removing the unwanted condensate from the system ensures there is less chance of damage from issues like waterhammer and corrosion. Steam traps remove the condensate as it forms, keeping better quality steam in the system and protecting pipework and equipment from erosion and corrosion.
The statistics really do speak for themselves. Take this example of an oil refinery that wanted to reduce its overall energy costs, carbon output, improve safety and production performance. Spirax Sarco engineers carried out a turnkey project involving a wide-ranging steam trap and energy audit of the site. The audit identified 20% of the steam trap population had failed leading to significant energy losses. Through the installation of new steam traps, the oil refinery achieved energy savings of £100,000 within 12 months with a payback period of 16 months.
Or how about the largest food factory in Europe? The Heinz factory in Wigan produces canned soups, baked beans, pasta and puddings for the UK and European market, and its on-site energy center generates up to 140 tonnes of steam per hour to keep the canning lines running. In order to reduce carbon emissions and save energy, Heinz worked with Spirax Sarco to implement a steam trap management program at the Wigan site following the success of a previous, one-off steam trap survey, which saved enough energy and treated water to pay for itself in less than nine months
Spirax Sarco engineers surveyed the site every six months; checking, tagging and recording the condition of each steam trap. “When Spirax Sarco carried out the original survey they put in a conservative estimate of savings and we ended up saving much more,” said Barry Aspey, a utilities manager at Heinz. “That helped us decide to opt for the three-year program. If the new savings estimates are correct, the program offers excellent value for money and should help us achieve a 4% reduction in energy consumption and reduce our carbon emissions by 200 tonnes a year.”
Could you be achieving similar results? The first step on the road to a greener future is to ensure all systems are working correctly and fully optimized – often the quickest wins too.