HRSG Cleaning with EPIC(™) Technology: A Safe, Proven Cost-Effective Solution

September 21, 2020

Maximize HRSG Efficiency & Performance While Cutting Operating Costs

When you want to ensure your HRSG unit is running efficiently, it occasionally needs to be off-line cleaned professionally and thoroughly. An exceptionally effective and safe technique incorporates targeted pressure wave impulse technology applied at Mach- 5 speed utilizing EPIC (Extraction Pressure Impulse Cleaner) technology.

This patented process has been developed and perfected for HRSGs after 14 years of success and experience with it’s on-line counterpart, including on HRSGs and up to 900 Mw boilers. EPIC’s technology and its unique remote-controlled navigation positioning equipment directly focuses localized energy into the finned tube bundles to ensure its deep, penetrating and 360 degree effectiveness reaches and cleans all the crucial heat transfer surfaces without superfluous indiscriminate blasting or explosions to non-essential components or structures.

When the EPIC process is utilized for your HRSG cleaning needs, you’ll be rewarded with reduced CT back pressure, fuel costs and exit stack temperatures as well as overall increased efficiency, and much more.

Not Optimizing HRSGs’ Performance Can Be Costly

When your plant’s HRSG unit is effectively cleaned, it will restore performance that was previously lost because insulating deposits increased the CT backpressure (thus output) and increased fuel consumption. This backpressure is most frequently the result of deposits that gradually build up and affix themselves to the close-tolerance finned tubes during HRSG operation, which is standard, particularly after 5-15 years of operation. Oftentimes, DP recovery can be 3-6”, which can yield a payback in 2-4 months of operation. However, without proper cleaning, HRSG units can experience increased back pressure resulting in the overall heat rate worsening and loss of efficiency, which may even cause de-rating in peak demand periods.

Factors Leading to High Operating Costs

  • Lack of optimum cleanliness of crucial heat transfer surfaces
  • Increased CT back pressure/decreased generation because of excessive deposits
  • Lower feedwater exit temperatures necessitating additional fuel to compensate for same
  • Wasting Btu’s going up the stack rather efficient convection-transfer to the ID of tubes
  • Requiring excessively more outage duration to attempt cleaning by other methods rather than getting back on-line quicker
  • Increased fuel costs due to otherwise unnecessary use of duct burners or excessive firing
  • Due to the expense of certain other methods, cleaning intervals may be excessively delayed and/or less than the optimum quantity of harp bundles are cleaned during a project

EPIC Cleaning System

The Extraction Pressure Impulse Cleaner is a state-of-the-art cleaning technology invented and patented by PowerPlus Cleaning Systems with Thompson Industrial Services as the exclusive provider of the service. The technology is based on a process originally patented by GE (but now owned by PowerPlus Cleaning Systems) and is used for off-line cleaning of HRSG units. This system has passed the test of time for both on-line boiler-cleaning— with nearly 14 years of use— and off-line cleaning in more recent times.

EPIC Overview

The EPIC pressure wave system was designed to improve current HRSG cleaning methods and do so safely and quite effectively without damage or stretching to any combined cycle components. Although various HRSG cleaning systems exist, all had their flaws, and none can now reach the same standards and controls set by EPIC. This proprietary technology removes deposits that have built up and are lodged deep into the harp’s finned tube bundles.

How EPIC Works

The EPIC system incorporates a special device called IMPULSE(R) (internationally patented), to deliver high-pressure (<40 PSI) cleaning pulses focused and targeted circumferentially to just the troublesome heat transfer surfaces. Essentially, the system uses air shockwaves that penetrate the tube banks to dislodge (i.e. “extract”) foreign deposits. The overall cleaning system is remotely controlled by a navigation system outside of the HRSG unit in Thompson’s mobile command center. The personnel navigating the cleaning system can maneuver the system in nearly all directions to avoid obstructions, and place the system in the correct spot to clean the finned tubes and free them of the insulating deposits.

EPIC-works

The Benefits of Using EPIC

  • Deep, thorough 360-degree cleaning of the critical tubes and fins
  • Zero damage done on any parts, components, welds, expansion joints or instruments
  • No shock or superfluous, indiscriminate blast impact to the rest of the HRSG unit
  • Highly technologically advanced; 6 camera views from command center; remote bundle differential pressure monitoring; multiple fail-safe features; borescope videoing before and after and more
  • Personnel are totally remote from the operating system
  • No scaffolding required
  • Reduced downtime for cleaning
  • Reduced combustion turbine back pressure
  • Improved heat transfer efficiency/decrease stack temperature
  • Overall financial gain
  • Optional drone inspections of HRSG and SCR

Case Study

A case study performed at a large combined cycle plant in Florida examined the benefits of EPIC technology on a Nooter/Eriksen HRSG unit. What the study found was astonishing. After a thorough cleaning with the EPIC technology, the HRSG unit experienced a decrease in CT backpressure by 4 inches of the water column. This correlated to a decrease in heat rate by 0.5 MMBtu/MWh. These impressive results yielded a payback in 1,000 full-load hours in payback, which equated to roughly $600,000 per year in this instance.

Conclusion

Every business in every industry should be planning for the future. To do so, they must all look to the newest technology, so they can compete and excel. For combined cycle plants, that means looking towards EPIC technology. With proven results, EPIC technology offers everything a combined cycle plant could target for; improved cleaning, safety, decreased downtime, zero damage, and an optimized HRSG unit.

If you want to improve the efficiency of your HRSG unit while saving money, request a consultation with Thompson Industrial Services to find out more about implementing Thompson’s EPIC technology and service at your plant.

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