HRSGs and boilers |
Figure 4. Soot build-up in a firetube boiler. Leak testing
Because fuel and heat are involved in making steam or hot water, there is always the potential for leaks and overheating of materials. Some leaks are more serious than others. For example, leaks in fuel delivery systems are sometimes easy to detect by odour, but other times require leak detection equipment. When firing fuels such as natural gas, propane, and hydrogen or hydrogen blended fuel, the boiler–burner fuel train should be periodically and routinely leak tested to ensure that fuel gas is not leaking into the boiler room. Obviously, this can present a very dangerous situation that requires immediate attention. Burning and deteriorating gaskets are another source of potential fuel and flue gas leakage.
Also of great concern is leakage of CO through boiler casings or stack/breech joints that may not be easily detected through the sense of smell. CO itself is colorless, tasteless, and odorless, and is produced in the combusiton process. In well tuned and operating burners, the CO produced in the combustion process is an intermediary step towards full conversion to CO2
. The flue gas should contain zero or near-zero CO and Figure 5. Boiler’s ability to satisfy demand over time
hydrocarbons. However, this is not always the case due to a variety of causes. Therefore, it is
recommended that: ● Combustion is checked at least semi-annually by a qualified boiler–burner service agent and the unit be retuned if necessary, with replacement of any worn or defective parts leading to the elevated CO levels.
● The auxiliary boiler room should be equipped with a CO detection and alarm system that will not only annunciate that CO levels in the boiler room have exceeded a specified value, but will also shut down the boiler and fuel supply until the issue can be remedied.
Higher efficiency and long life In summary, described above are just some of the early warning signs that an auxiliary boiler and boiler system may need attention. Keeping an eye on these early warning
signs while performing routine and periodic inspections and maintenance will help to achieve peak operating efficiency and a long boiler life.
*Mike Valentino is a technical consultant for the American Boiler Manufacturers Association (
ABMA.com).
Since its founding in 1888, ABMA has advocated for the safe production and operation of and provided solutions for its member companies. From 31 March to 2 April, ABMA is hosting BOILER 2026 in Nashville, TN, USA — a world-class expo and conference for the boiler supply chain, bringing together boiler collectively seek out best practices and solutions to industry challenges. For more details visit
abmaboilerexpo.com.
Oil-to-natural-gas conversion in Vietnam
Mitsubishi Power is working on an oil-to-natural- gas fuel conversion project at the O Mon 1 Thermal Power Plant in Can Tho, southern Vietnam. It will provide the main equipment, such as the gas burners for the boiler, leveraging its position as OEM (original equipment manufacturer) of the original boiler and power plant main equipment supplier to carry out the fuel conversion. In addition, Mitsubishi Power is installing a selective catalytic reduction (SCR) system, allowing the plant to meet stricter environmental regulations in the future. The O Mon 1 Thermal Power Plant comprises unit 1 (330 MW) and unit 2 (also 330 MW), which started operation in 2009 and 2015, respectively. The fuel conversion project is being conducted by Power Generation Corporation 2 (EVNGENCO2), part of the Vietnam Electricity Corporation (EVN) Group. The contractor for engineering, procurement, and construction (EPC) is a consortium of LILAMA Corporation, a construction company under Vietnam’s Ministry of Construction, and Power Generation Corporation 3 (EVNGENCO3), also part of EVN
Group. Mitsubishi Power received the contract for the fuel conversion main equipment from this consortium. Singapore-based Mitsubishi Power Asia Pacific Pte. Ltd is providing EPC engineering support and dispatching personnel to provide technical assistance. Commenting on the contract award, Makoto Fujita, Senior General Manager, Steam Power Business Division, Energy Systems at MHI (parent company of Mitsubishi Power), said, “Since the start of operations of unit 1 in 2009, the O Mon 1 Thermal Power Plant has played an important role in the development
of the Mekong Delta region. As the OEM of the existing power plant, we are extremely proud to be able to contribute to the stable supply of energy and decarbonisation in Vietnam through our participation in this fuel conversion project.” In August 2025, Mitsubishi Power received a contract to supply two J-Series Air-Cooled (JAC) gas turbines for the O Mon 4 Thermal Power Plant, a 1155 MW combined cycle plant adjacent to the O Mon 1 Thermal Power Plant, scheduled for completion in 2028.
Vietnam’s Power Development Plan VIII (PDP8) calls for diversifying the energy mix, reducing coal dependency, and expanding natural gas and renewable energy. Vietnam has a national target that envisages achieving net zero emissions by 2050.
O Mon 1 Thermal Power Plant 20 | March 2026 |
www.modernpowersystems.com
Akihiro Ondo, CEO and Managing Director of Mitsubishi Power Asia Pacific Pte. Ltd, said, “Vietnam boasts the highest real GDP growth rate among the ASEAN-5 nations. We are committed to contributing to Vietnam’s economic development by leveraging cutting-edge technology and providing meticulous services.”
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