SigmaClean™: Revolutionizing the Heat Recovery Steam Generator (HRSG) Preparation Process
June 19, 2023 J.J Malloy

SigmaClean™: Revolutionizing the Heat Recovery Steam Generator (HRSG) Preparation Process

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SigmaClean™ is one of BEST Energy Services, Inc.‘s leading offerings in the field of industrial cleaning. It is a method specially designed for washing and passivating the internal surfaces of Heat Recovery Steam Generators (HRSG), aligning operational chemistry with a zero hazardous waste agenda. The process is unique in its capacity to simultaneously test Boiler Feed Pumps to baseload while conducting the cleaning and passivating.

Systems prepared for operation using SigmaClean™ include Boiler Feedwater Pumps, HP/LP Economizers, HP/LP Evaporators and Drums, the Condensate System, and the Boiler Feedwater System.

“SigmaClean™ revolutionizes the process of preparing the Heat Recovery Steam Generators for operation, transforming what was once a wasteful process into an eco-friendly method that eliminates hazardous waste while simultaneously optimizing system efficiency. It’s not just about cleaning; it’s about creating a sustainable future for the energy industry.”

SigmaClean’s goal is to transform reactive iron surfaces to a passive state, replicating the conditions on the surfaces after prolonged operation under standard circumstances. This is achieved by circulating a solution of demineralized water laced with all volatile chemistry at elevated temperatures. This process is executed to condition the watersides of the HRSG for operation.

This method creates an oxygen-depleted, high pH environment that promotes the formation of a passive form of iron oxide called Magnetite. This inorganic polymer possesses extremely low solubility in demineralized water, making it an ideal passivating agent. The elevated pH also helps in removing any light oils that might be present due to the manufacturing and assembly process. This chemistry is compatible with all components being cleaned, including the Boiler Feed Water (BFW) pump.

In conjunction with the chemical processes, SigmaClean™ uses the BFW pump to elevate the temperature of the solution. The pump operates at full flow and pressure, transforming the mechanical energy into heat and raising the temperature of the circulating solution above 212°F (100°C). This process also enables the commissioning of the BFW pumps to be performed earlier than usual, off the critical path and before the steam operation of the HRSG.

BEST Energy Services, Inc. also integrates a temporary filtration system into the process to remove contaminants present in the waterside components of the HRSG. The system, combined with high rates of circulation and elevated temperatures, is particularly effective in cleaning the tubes and lower headers.

Once the elevated temperatures in the HRSG are achieved and maintained, along with the necessary chemistry for a minimum of 24 hours, the process is not stopped until full conversion of the internal surfaces to magnetite is verified, and BFW pump suction strainers are free from particulate.

SigmaClean™ continues to successfully eliminate the need for aggressive chemical cleaning, making use of acids or chelants and creating waste streams that require offsite disposal redundant.

SigmaClean™ also minimizes the need for large staging areas and extensive flushing. It does not require an elaborate set of pumping equipment, heat exchangers, steam generators, piping, or hoses. Only two boiler volumes of demineralized water are required for SigmaClean™. Moreover, it uses the same all volatile chemistry as used during the normal operation of the HRSG and produces waste similar to concentrated blowdown. This results in no need for chemical disposal and avoids the use of extensive batteries of frac tanks to stage and rig.

The result of SigmaClean™ is an HRSG with clean, passivated watersides that produce no BFW strainer trips during the steam blow. The superior passivation provided by SigmaClean™ also makes it easier to achieve and maintain chemistry during operation.

The VGB 513e Guidelines on Chemical Cleaning clearly recommend performing chemical cleaning if the number of deposits in the evaporator exceeds certain limits. These guidelines further raise a few questions:

  • What is the amount of mill scale or deposits on a new HRSG?
  • What is the specification set forth on your project for acceptable deposits on the boiler when purchased?

SigmaClean™ is the answer to these questions, providing a solution that guarantees clean and passivated surfaces. It ensures that your HRSG is prepared optimally for operation, and the strict adherence to operational chemistry ensures no hazardous waste generation.

SigmaClean™’s unique capability of achieving high standards of cleanliness while causing minimal environmental impact is a paradigm shift in HRSG preparation methods. It not only ensures adherence to critical guidelines but also optimizes the project’s economic efficiency.

The environmental and economic advantages of SigmaClean™, coupled with its proven efficiency, positions it as a trailblazer in the field of HRSG preparation. Whether it’s the simultaneous testing of Boiler Feed Pumps or the effective transformation of reactive iron surfaces to a passive state, SigmaClean™ embodies a method that encapsulates effectiveness, efficiency, and environmental responsibility.

As we move towards an industry future where sustainability and operational efficiency are not just desired but expected, solutions like SigmaClean™ are not just alternatives – they’re necessities. It is an innovation in industrial cleaning that is poised to reshape our understanding of operational preparation for HRSG and similar systems, setting new benchmarks for environmental sustainability in the industry.

The result? An HRSG operation that is environmentally responsible, economically efficient, and operationally superior, thanks to SigmaClean™.

Now, the question remains, “Are you ready to revolutionize your HRSG preparation process with SigmaClean™?”

#SigmaClean #HRSG #IndustrialCleaning #EcoEfficiency #GreenEnergy #PowerIndustry #EnvironmentalStewardship