HRSG cleaning is an essential part of the system maintenance plan. A clean system not only increases the lifespan but also enhances the plant’s efficiency. In systems with diesel generators or gas turbines, this also means the system will generate more power. Let’s find out the details of the HRSG system cleaning needs and the purpose of the maintenance plan.

About the HRSG system – Objectives of HRSG cleaning and methods of implementation

As mentioned above, cleaning HRSG is an urgent job in the factory and is becoming more and more popular. It is crucial when cleaning to pay special attention to protect the pipes. Scheduling maintenance during plant downtime is an innovative and convenient plan. So which HRSG cleaning methods are rated as the most effective? First, let’s find out the overview of the HRSG system.

What is the HRSG system? Why does HRSG cleaning play an important role in plant performance

The HRSG (Heat Recovery Steam Generators) system is used to recover energy lost from thermal oxidants, gas turbines, or other heat-generating processes. Thermal boilers recover this energy to produce hot water and steam for other components through waste heat recovery.

What is the HRSG cleaning

Waste heat boilers can produce hot water or steam for other components through waste heat recovery. Oil-fired boilers, gas-fired boilers, and coal-fired boilers with waste heat recovery from smoke boxes and chimneys are also known as waste heat boilers.

Large HRSG systems are widespread in large energy projects or energy-efficient combined cycle power projects around the world. Universities or large construction sites often use HRSG systems to recover energy from diesel generators or gas turbines to power their campuses. Then, this recovered energy is used to heat or supply hot water to residential areas. This application is called Combined Heat and Power (CHP).

Importance of HRSG cleaning and goals of planning periodic cleaning

Some situations can cause blockages in the heat recovery steam generator (HRSG): scale build-up in the tubes; the sulfur in the fuel reacts with the ammonia used to control NOx, creating salts; and corrosion due to pipe leaks, water dew point condensation. When the system is clogged, it will directly affect plant performance in two ways: increasing the pressure drop on the exhaust side, leading to reduced gas turbine efficiency. The other, it reduces the amount of steam, leading to reduced steam turbine output. Most of these problems can be solved by HRSG cleaning.

Importance of HRSG cleaning

Maintenance and inspection during cleaning also provide an overview of the system’s status. The conditions inside the HRSG cannot be determined by external examination. Inspecting the inside is the only way to know if scale, pitting, or other damage. From there, detect problems, failures and promptly handle them.

Heat Recovery Steam Generation systems can be vast and complex systems that require planned maintenance, HRSG cleaning with appropriate service. A third-party professional service would be the best option. Boiler maintenance and repair professionals and contractors can test, analyze and offer more effective system management options consistent with the current state of the HRSG system.

Standard HRSG cleaning methods improve system performance

High-pressure water cleaning technology, particle blowing, CO2 blowing (dry ice), and pressure wave cleaning are the four types of standard HRSG cleaning technology on the market. Each type has its benefits, the choice of which is often decided on a case-by-case basis. The following content will present the two most popular methods today: CO2 Ice Blast Cleaning, Pressure Wave Cleaning.

Dry ice sublimes when it goes directly from the solid state to the gaseous state. This industrial cleaning method is applied by blowing frozen CO2 pellets onto the contaminated surface with a high-pressure compressor. An expansion of 750-800 times the original volume of CO2 separates debris and dirt, which is then removed by vacuum devices.

Scaffolding or access devices suitable for the system are required to conduct the inspection and perform cleaning work. In case of other needs, one can use a chemical solution to clean the remaining hard deposits.

Standard HRSG cleaning methods

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Pressure Wave Cleaning is an HRSG cleaning method developed by BANG & CLEAN Technologies AG of Switzerland in 2001 and licensed by GE in the United States. A balloon filled with a flammable mixture is ignited near the tubes to be cleaned. The pressure waves and vibrations of the tubes loosen debris and plaque, which then fall to the floor. Since the process carries out a series of explosions (100 or more), it is remotely controlled to prevent injury and danger to workers.
Developing a systematic HRSG cleaning plan will help optimize system performance and minimize system downtime. This work also helps to limit unexpected damages and malfunctions, leading to higher costs. And choosing a professional and reputable unit will help you solve the above problems and build an effective cleaning and maintenance process.

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