As a plant manager, specifier or operator, you probably have questions regarding ‘Steam Fundamentals’. To help you get ahead and avoid the unnecessary, and often time-consuming task of trawling Google for the answers, I’ve put together a list of the most commonly asked questions in the steam industry.
Having a solid grounding in steam fundamentals will serve you well, allowing you to achieve better safety and efficiency by planning and implementing steam and thermal energy improvements.
Read on for the answers to the frequently asked questions.
As water nears its boiling point, certain molecules build-up enough kinetic energy to momentarily escape before falling back into the liquid. Further heating of the water causes bubbles of steam to form within the water and rise-up to break through the water surface to form saturated steam. As the steam loses heat it begins to turn back into water– doing so almost immediately as it leaves the boiler. This water is known as condensate.
There are three main types of steam:
Saturated steam is the steam that is created when water is heated to its boiling point and then vaporised with additional heat. Water in the boiler under pressure will increase the temperature of the water and the steam.
Superheated steam occurs when steam is at a temperature higher than its original saturation temperature.
Flash steam is the name given to steam that is formed from hot condensate when we get a pressure drop.
Steam is generated by heat from the combustion gases of fuel in a furnace of the boiler. This heat is then transferred to the water inside the boiler, this then evaporates the water to create steam under pressure.
Very briefly, saturated steam tables list the various properties of steam at differing pressures, including, saturation temperature, specific volume, and latent heat.
Steam is a versatile product that can be used in a number of key industries. For instance, clean steam can be used in direct injection processes in the food industry to avoid the risk of inconsistencies in product taste and taint that can result when normal culinary steam comes into contact with the end product. While in the hospitals and health industries, where clean steam forms part of the NHS’ drive to improve hospital sterilisation services, steam also generates a constant supply of hot water for hospitals and areas such as laundries and kitchens.
There are a range of tools that can be used to assist you in the monitoring of your steam system’s performance. The B850 Boiler House Energy Monitor offers a flexible solution for monitoring energy transfer throughout the boiler house.
Alternatively, steam system audits are available to assist you in monitoring your steam systems. These audits enable you to benchmark your entire system and its operation. Following the audit, a detailed and comprehensive report is produced to show you how well your steam system is currently performing. For those who need an extra helping-hand in monitoring their steam system and maintaining their equipment’s performance, a service contract could be ideally suited for bringing peace of mind.
Energy or cost savings of up to 20 per cent can be harnessed by inviting a specialist auditor to assess your hospital or food factory’s steam system and implementing their recommendations.
Chris Coleman, Condensate Handling Specialist
If you are under pressure to reduce the running costs of your boiler house, then I have some tips you may find useful.
If you’re involved in the planning or upgrading of boilers, or responsible for the day to day running of steam boilers - large and small - you’ll need to know your way around a boiler. You’ll also need a basic understanding of the properties of steam.
Steam is an incredible heat transfer medium. Every kilogram of steam contains around 2200 kj of condensable energy. That’s 26 times more usable energy than a kilogram of water in a typical heating system based on flow and return temperatures with a delta of 20oC.