5 ways to optimise your steam system

Whether it is ensuring that your critical services are working correctly, saving energy and reducing carbon emissions, or planning for future plant upgrades, here are five ways to help you achieve your goals.

1 Measure and Save

With fuel prices rising and legislation to control carbon emissions tightening, the importance of finding new ways to save energy is a constant on the agenda for many steam-using organisations.

Some of today’s most cost effective energy reduction schemes rely on motivating people to think about how they can better manage their energy consumption. By making an organisation’s individual departments or cost centres accountable for their energy, the responsibility for saving is placed with the user.

The first step in making users pay for the energy they use is to measure their actual consumption. The more accurate the metering, the better the control over consumption. The boiler house is an area where significant savings can be made by eliminating wasteful consumption.

It is vital to choose meters that take into account the specific needs of metering different fluids. For example, steam is a relatively slow flowing, high temperature fluid with varying density, often feeding variable demand and with entrained moisture that can significantly affect the accuracy of reading.

Meter accuracy is another significant factor in the equipment selection process, but turndown, which is the ratio of the maximum and minimum flow rates the meter can measure, is often even more important. It is sensible to select meters with a turndown that is enough to cover the full flow range, including consideration of future changes to the steam plant. 

Very often, great energy efficiency achieved as a result of installing metering can help recoup the cost of installation in just two years. However, it is essential to choose the right meter for the job.

To effectively manage the cost of steam, owners and operators need to know where steam is used, how much is used, whether it is being used effectively and how its consumption can be optimised. This effectively puts metering equipment at the heart of any effort to monitor and target energy consumption.

Many organisations rely on steam metering alone. However, this does not provide a complete picture of how efficient a boiler is. The only way to obtain the real boiler efficiency is to meter all of the energy into the boiler (in the fuel and feed water) and compare this with the useful energy in the steam that comes out of the boiler. This is needed to identify energy losses that occur after the burner, such as scaled or dirty heat transfer surfaces or excessive boiler blowdown rates.

Explore the range of Spirax Sarco meters that are simple to use, delivering accurate and reliable data at sxscom.uk/metering.

2 Insulate

It is common knowledge that a well-insulated industrial building will save energy, lower utility costs and decrease carbon footprint. While we usually focus on the obvious such as loft insulation, cavity wall insulation and others to increase the energy efficiency of an industrial building, we tend to overlook those areas that would greatly benefit from insulation, such as a steam system.

Insulating steam systems is the most cost-effective energy-saving measure that operators can make. Yet many steam traps, valves and other equipment are left uncovered to allow easy access for maintenance.

Typically, a non-insulated steam trap will lose about as much heat as a one metre length of bare one inch diameter pipe, equating to a loss of £170 per year. Steam systems are often populated with 100 or more traps and valves, which, if not insulated, can mean several thousands of pounds in lost energy annually.

Explore the range of Spirax Sarco insulation jackets at sxscom.uk/insulation.

3 Implement heat recovery

Flash steam is an unavoidable loss – it’s part of the steam-using process. What you can control, however, whether you decide to recover this lost energy and water, and re-use it in another process. 

If you consider that around 14% of steam used at 8 bar g turns to flash steam, a plume represents a significant loss of water from a system. Food manufacturing processes that use large quantities of high-pressure steam, such as steam jacketed vessels or rotary dryers, produce more flash steam. There is potential for this lost energy to be captured and recycled so you can reuse it in another process 

Saving money and energy are the obvious advantages of implementing heat recovery. In addition, a lower carbon footprint, and even the mitigation of reputational risks might tip the balance when it comes to deciding whether to invest in flash steam recovery.

Before you look to recover heat energy from a plume into another process or system, it’s important to identify and address any controllable heat energy losses in your system. If not accounted for, these hidden losses can affect your return on investment. Furthermore, without this diagnosis, it’s impossible to have a realistic expectation of how much energy you will be able to recover from your flash steam plumes.  

Controllable losses can occur due to:

•Passing steam traps
•leaking safety valves
•other repairable leaks.

These can be avoided through a number of actions, including scheduling regular steam trap surveys with a steam system expert, keeping stringent records of your safety devices, and continual monitoring of your key plant and steam-using equipment.

A specialist engineer will be able to identify the root causes of your steam loss and determine if there is an opportunity for flash steam recovery at your food manufacturing plant.

Benefits of Heat Recovery

Cost savings
With payback periods of flash steam recovery as short as 12 months in some cases, saving money may appear the most desirable advantage, but cost efficiency is certainly not the only benefit. Condensate is, essentially, heat energy and any that is lost from your steam system must be replaced by cold water that must be treated and heated from a lower temperature. This incurs both fuel costs and also water charges. 

Water savings
A Process using steam that runs on approximately 10 bar g, could lose around 15-16% in flash steam. Particularly in water-scarce regions, that’s a significant loss. In these cases, the return on investment calculation can start to appear extremely favourable and tip the balance in favour of implementing the flash steam recovery process.

A more efficient system 
Condensate is distilled water and contains almost no total dissolved solids (TDS). Returning more condensate to the feed tank reduces the need for blowdown – the process that reduces the concentration of dissolved solids in the boiler water. This reduces the energy lost from the boiler.

Mitigate reputational risk
Flash steam is visible and may even be considered an eyesore. While flash steam plumes have no negative impact on air quality, they can be confused in the eyes of the public with harmful CO2 emissions. Although this is a misperception, some manufacturers may wish to reduce their visible steam plumes, especially if they can capitalise on other benefits of flash steam recovery. 

Flexible energy recovery
Depending on your processes, it can make sense to capitalise on your flash steam plumes during certain times of the year and depending on the temperature. Some food manufactures require more energy during colder months, for example to keep oil at a certain viscosity. A professional engineer will be able to advise how you can maximise the benefit of your steam plumes in line with your processes, so you reap the rewards. 

Flash steam recovery may be a great idea however it’s just one part of the picture. Having a specialist engineer assess your entire steam system is an opportunity to ensure you’re operating sustainably.  

Modern, variable speed condensate return systems such as the Spirax Sarco Condensate Recovery Unit can help to capture all your valuable condensate. Find out more at sxscom.uk/condensatereturn.

4 Decarbonise Steam Generation

Today’s boilers are highly efficient, minimizing the amount of energy needed. Steam also has a high heat content and energy density, which means that the production infrastructure and pipework can be compact, thus saving space and using less raw materials.

As the world moves towards more electricity production from renewables, steam will become even more sustainable and low carbon: it can be produced by clean electricity, green hydrogen or in biomass boilers, so making steam with reduced carbon emissions achievable right now. For example, it is a key part of energy solutions such as thermal storage and combined heat and power (CHP) systems. 

Managed correctly, steam is intrinsically clean and safe. With no fire risk or toxic waste products, the only by-product is water. This can be condensed and re-used in a similar way to the natural water cycle of rain and evaporation that keeps our planet alive.

The potential benefits offered by steam are massive. For example, 35 per cent of all the UK's industrial heating is achieved by steam systems. As 73 per cent of the UK's total energy demand is for heat, improving the efficiency of steam generation will have a big impact1.

 

Clean Technology

To support these environmental objectives, Spirax Sarco is developing new technologies to ensure steam is a long-term part of our decarbonized future.

When used with 100 per cent renewable power sources, such as hydroelectric, solar and wind, electric steam generators have no emissions and generate no carbon dioxide. They can convert renewable electricity into steam at 97 per cent energy conversion efficiency.


Another option is using green hydrogen as the fuel to heat water and generate steam. This technology also reduces flue gas volumes by 10 per cent, thus significantly improving boiler efficiency.

 

Steam can also be generated by combustion of organic waste materials such as olive pulp, rice husks and palm kernel shells, which are the by-products of food production. This biomass can be used to generate electrical energy as well as heat, when used in a Combined Heat and Power (CHP) system. The reduction of organic waste and the utilization of biomass improves environmental sustainability, while also reducing energy bills.

 

Steam in practice

Clearly, there are benefits to be derived from different approaches to steam, but what does a steam system actually consist of?

The core of a steam system is a boiler, which today often burns fuels, but could instead be run using electricity or biomass. The heat from the burner sends hot gases through tubes in the boiler, which run through the tank of water that is being heated. 

Once the water is hot enough, it boils, and bubbles of steam are produced which are then routed through pipes and valves in the steam system. The temperature of the steam depends on the pressure in the boiler and might typically be >150ºC.

Once the steam reaches its destination in a factory or plant, there are many ways it can be used: for example, in an ‘autoclave’, which is a steam-filled chamber to sterilize medical equipment, or to boil or cook food, using a ‘jacketed pan’ which surrounds the pan with a jacket filled with steam.

Typically, the flow of steam will be measured at multiple points throughout the system, enabling energy consumption and efficiency to be closely monitored. As part of the growing digitalization of industry, including the shift to the Industrial Internet of Things (IoT), this presents an opportunity to optimize and automate the new steam technologies, to save money with preventative maintenance, and to drive greater efficiencies. 

 

Making a difference

Steam is a tried and trusted technology, based on well-understood principles with reliable outcomes. Steam provides a low-risk, low-cost way to reduce emissions on the route to net zero, without requiring the ‘rip and replace’ of existing infrastructure.

Natural Technology is supported by decades of engineering expertise.

It is based on specific, measurable outcomes, which are substantial enough to make a real difference – and which enable organisations to clearly demonstrate their commitment to sustainability.

It will enable industry to de-couple from fossil fuels and embark on a more sustainable route to zero carbon steam systems for heat, power, and sterilisation. 

Explore the latest decarbonisation solutions at sxscom.uk/targetzerosolutions.

5 Improved Plant Management and Preventative Maintenance

Planning for engineering or operational management including service, maintenance and monitoring is key to establishing an all-encompassing energy management approach. Having invested in new plant or in a programme to improve your steam system to bring it up to its best operating efficiency, you’ll want to keep it that way. Often, the most cost-effective way to do this is to outsource some or all maintenance work.

A good place to start is to take a look at your steam trap population, which is the most important link in the steam and condensate loop. We know that removing condensate and air from your steam system is essential whilst returning condensate to the boiler house maximises 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 programme 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.

 How can improved plant management and preventative maintenance help you?         

1. 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. 
   
   
2. 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. 
   
   
3. 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 minimising 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. 

    

4. 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.
   
   

Find out more on Spirax Sarco’s range of Aftercare Services and Support at sxscom.uk/aftercare.

1 Source: Aggreko Report (March 2021), included at https://www.natural-technology.com/en

2 https://www.anu.edu.au/news/all-news/anu-scientists-set-solar-thermal-record

3 https://www.natural-technology.com/en