Tips for effectively maintaining your steam systems
Here at PIF we scour the web looking for handy tips and tricks and we came across steam system expert, Paul Mayoh, Technical Manager at Spirax Sarco, and his five easy tips to get the most from your entire steam and condensate system.
1. Water supply to steam systems
The basic starting point for any efficient steam system is a clean water supply. Raw water, with its array of impurities, can have a drastic impact on the performance of steam systems. The most common impurities you're facing are dissolved solids and gases, scum-forming substances and suspended solids, with three categories of damage: corrosion, deposits and foaming.
First rate water treatment tackles these problems at source, traditionally involving water softening supplemented by chemical treatment. Increasingly popular, Reverse osmosis (RO) forces water through a semi-permeable membrane to eradicate most of the contaminants, resulting in pure water with 98-99% of its salts removed.
2. Correct Boiler Control in Steam System
Having the right controls is a crucial ingredient in the optimisation of any steam system. Level controls ensure sufficient water is fed to the boiler to meet demand. Low water levels mean the heating surfaces could become exposed and the boiler would overheat. Too high, and water could be sucked into the steam, leading to poor quality steam that could impair heating or production efficiency and increase the risk of waterhammer.
Better boiler controls deliver major savings, especially in the area of boiler blowdown. Boiler blowdown periodically ejects water from a boiler to prevent the build-up of contaminants, with two varieties: side blowdown (to control total dissolved solids) and bottom blowdown (to control sludge in the bottom of the boiler). Switching from manual opening of the blowdown valves to automatic blowdown controls can deliver a rapid return.
3. Effective Heat Transfer in Steam Systems
Whether steam is used to drive an industrial process or provide heating and hot water, effective heat transfer is critical for almost every installation. So the most efficient heat exchangers should be a priority.
Traditional shell-and-tube calorifiers look increasingly outdated compared to more efficient, compact alternatives. Plate heat exchangers typically improve energy efficiency by around 6-10%, simply by reducing radiation heat losses from their surfaces. These compact systems can be so responsive that some of them can tailor their output on-demand.
4. Condensate recovery in Steam Systems
Condensate contains roughly 20% of steam's energy, which makes it a particularly valuable resource. Most systems could achieve a condensate recovery rate of 75-80%, thus saving thousands of pounds a year in energy alone. Using hot condensate to heat the boiler feedwater means the boiler has less to do in converting the water to steam and every 6°C temperature boost in boiler feedwater knocks 1% off a typical boiler energy bill. Any condensate returned to the boiler feedtank reduces the need for blowdown, helping to lower the energy lost during the blowdown process.
When it comes to condensate recovery, each steam system is different and only a technical assessment and cost saving calculation can determine the payback of a particular project. However, typically the payback is between one and two years, with some measures paying for themselves in weeks.
5. Service and support of your Steam System
With the much-discussed skills gap affecting many organisations, and in-house estates and maintenance personnel facing increasing demands on their time, calling on specialists to provide service and support for the steam system can be the most realistic, cost-effective route to maximal productivity.
Everything we've talked about here is either low or no-cost and even when a hefty upfront investment is needed, you really should start seeing the benefits almost immediately.
Get the latest process industry news
Interested in receiving even more industry-leading news from Process Industry Forum delivered directly to your inbox? Then sign up to our free newsletter. Bringing you the latest news, trends, innovations and opinion from across the process industry, our exclusive newsletter gives you all the industry insights of the moment in one, easy-to-digest bulletin. Stay ahead of the competition with regular process industry news instalments from PIF.