What comes to mind when you think of steam?
Steam’s uses are very much relevant in the world today as an essential part of many applications across a broad range of industries including humidification, sterilisation, cooking, cleaning and even cooling.
From the boilerhouse, through the distribution system and into the plantrooms, there are many areas of consideration when looking to optimise a steam system. It may seem obvious, but ensuring that lagging is of a good standard is crucial for example, in maximising system efficiency. This is of course relevant to any medium, but an ageing installation will often offer significant opportunity for improvement.
Boiler water feedtanks have traditionally been atmospheric units in the UK. More commonplace in Europe is the Pressurised Deaerator, which operates just above atmospheric pressure, thus driving off oxygen from the feedwater.
This helps to improve the quality of the steam and condensate, therefore increasing the longevity of the steam infrastructure. Its low-pressure operation provides an effective way of capturing surplus energy that may be found in the boilerhouse, boosting overall system efficiency.
Boilers have two key areas where energy can be recovered; one being to capture the thermal energy in boiler flue gases using an economiser, which is typically used to pre-heat the feedwater going into the boiler, and the other being boiler blowdown, where hot water is discharged from a boiler to maintain the internal dissolved solids level at an optimum. Fuel savings from each can typically be between 3 and 5%.
In the distribution system, steam traps are essential in the safe and effective operation of a steam system. Whatever type of trap is employed, there will be an aspect of maintenance required to maintain maximum system efficiency, whether it be cleaning a strainer or changing a trap.
Traditionally made of a number of separate components (valves, strainers, etc.), the latest generation of one-piece trapping solutions have reduced potential leak paths from a typical 18 to just 3, vastly reducing maintenance and associated costs.
It is important to have the ability to access any trapping item quickly and effectively. Steam traps such as the STS17.2 has transformed the way this is achieved and has found favour across many industries with its integral componentry, saving time and money by helping sites to keep steam traps running at maximum efficiency.
In plantrooms, steam-to-water plate heat exchangers offer an energy-efficient alternative to the traditional shell and tubes in the generation of hot water. Modern plate heat exchangers are designed to operate at optimum conditions for efficiency and also have the added-value benefit of reduced operational costs, eliminating the ongoing strip-downs that calorifiers require for insurance purposes.
Space is increasingly at a premium in facilities. When considering a traditional plantroom, there may have been a number of large domestic hot water (DHW) or process hot water calorifiers occupying a considerable footprint.
This can usually be satisfied using steam-to-water plate heat exchangers that deliver instantaneous hot water from a much smaller footprint. Not only does this provide benefits in terms of reduced losses (no radiated losses from stored water volumes) but it also helps to minimise the legionella risk by the removal of the stored water volume.
Condensate recovery provides substantial benefits to those who manage the finances of their facility. Condensate is ideal for use as boiler feedwater as it has both heat content and is of a quality to minimise boiler blowdown, resulting in energy savings.
Returning condensate will not only minimise raw water use, but also reduce the amount of boiler treatment chemicals consumed, this time with an associated financial saving.
Taking a new approach to steam has significant potential to future-proof any facility. Centralising and consolidating the thermal source would maximise the output of any Combined Heat and Power (CHP) plant that may be under consideration.
CHP works by utilising a fuel source to generate electricity which the facility can then make use of. The CHP engine can use the hot exhaust gas to produce steam, which can then be effectively transferred across site. This source of thermal and electrical generation is more efficient than traditional means of power generation.
With the emphasis on reducing greenhouse gas emissions, the future could well bring about change to our primary energy sources. What fuel will be used in the facility of tomorrow? The centralisation of boiler plant helps facilitate these changes, adapting to the fuel change at one point, whilst that excellent energy-carrying capacity of steam can still be utilised, serving all the significant users around the site, or even off site.
So if centralisation helps future-proof against changes in fuel supplies, how does this high-energy steam get transferred to the various areas of the site?
The reduction of an item’s electrical energy consumption is very topical. All around there are ideas to reduce electrical energy consumption, from LED lighting to variable speed drives on pumps.
At a time when we seek this reduction, it is important to know that with steam we have a medium capable of delivering megawatts of energy, yet it does not require pumping to get from A to B. It travels from areas of high pressure to low pressure under its own steam, if you excuse the pun.
Steam’s use clearly shows that it is still very much an important part of industry today and why so many facilities have been built with steam running through their veins. While the way facilities look and function may well change in the near future, the versatility of steam will help to ensure that manufacturing industries can continue to deliver, whatever the 21st Century may bring.
For more information on embracing steam in your process, why not download your copy of The unsung hero of boilerhouse efficiency whitepaper?