Steam System Efficiencies: Part 3

During the first two installments of our three-part steam blog series, we discussed the inefficiencies and waste that are prevalent in industrial steam systems and went on to explain how efficiency and profits can increase as functions of targeting life cycle cost reduction and running equipment on demand.

The final component that can aid targeting life cycle cost reduction and running equipment on demand is that of focusing energy on optimizing the entire steam system. This approach evaluates the entire system as a whole, rather than individual parts. Identify both supply-side and demand-side losses and improve upon each area in order to maximize efficiency.

Supply-side losses include stack loss, standing loss, and blowdown loss.

  • During combustion, heat is lost to the outside environment with exhaust, instead of being transferred to water to make steam. Installation of recovery systems designed to capture and repurpose heat can decrease the amount of heat and energy lost up the stack. At a minimum, this recovered energy can be used to preheat boiler feedwater.   The warmer the water is initially, the less it needs to be heated in order to reach its boiling point.
  • Standing loss involves the loss of heat from the boiler, itself. This type of supply-side loss is often minimal today, as modern boiler systems are well insulated to reduce the amount of heat that escapes the system. For older existing equipment, review your options to improve insulation to minimize this.
  • Blowdown loss is the most complicated type of supply-side loss that we will address. Often times, suspended solids are left behind in the boiler when steam evaporates, causing poor heat transfer, foaming, and water carryover into the steam line. Simply removing solids and replacing the evaporated water temporarily fixes the problem, but does not stop this process from happening again and also removes heat from the system. The most effective way to treat this problem is to better treat feed water and by returning purer condensate back into the boiler.

Demand-side losses include steam trap loss, condensate flash loss, pipe insulation loss, and pipe leakage.

  • Designed to remove condensate from the system, steam traps using less steam to operate are always more efficient.  Next, trap reliability minimizes costs due to trap failure.  While closed traps compromise the process, open traps allow significant energy to escape.  Each case carries high costs.
  • Lack of proper insulation for piping systems is also a major source of demand-side loss. Not only does insulation protect workers from burns, but it also tends to reduce radiant energy loss by 90%. More durable insulation methods protect from damage, ease of installation and maintenance ensures that upkeep can be preserved, and water resistance guards insulation against water absorption.
  • Finally, companies should always plan for pipe leaks, because wet, high-pressure environments lend themselves to pipe issues. Not only can steam and condensate leave the system and cause moisture and energy loss, but leaks can impact pipe insulation and encourage heat transfer. Pipe inspection is vital and can be performed easily with use of thermal imaging equipment.

If you’d like to learn more about steam system efficiencies, please read Ted Clayton’s white paper, “Practical Perspectives on Optimizing Steam System Efficiency.”

Estimated Reading Time: 2 minutes

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