The 6 boilers at the power plant of PT Bintan Alumina Indonesia were gradually commissioned and put into operation from March 2021 to July 2023. After commissioning, it was found that the boilers generally had relatively high exhaust gas temperatures. Following continuous long-term operation, the exhaust gas temperature approached 180°C, which directly affected the safe and stable operation of the desulfurization system. At the same time, it reduced boiler efficiency, increased production costs, and lowered the economic efficiency of the industrial park production lines.

Because the boilers had been operating under low-load conditions, the flue gas velocity in the economizer also decreased accordingly. In addition, there was a significant deviation between the actual coal quality and the design coal quality, along with the continuous co-firing of coal gasification fly ash and other factors. Although the temperature could be temporarily controlled, it remained consistently high.

To address the issue of excessive boiler exhaust gas temperature, the boiler workshop began contacting the Huaxi Boiler Design Institute in October 2022 and, by the end of May 2023, conducted new thermal calculations and cause analysis. At the same time, the workshop coordinated with the pulverizing system equipment manufacturer and the air preheater manufacturer to carry out comprehensive verification calculations and analysis.

Ultimately, with the approval of company management, it was decided to first conduct a trial by installing steam soot blowers on the boiler economizer. At the end of May 2023, engineering drawings were completed, followed by quantity calculations, submission of equipment and material procurement plans, and inquiries to installation contractors.

After the project to install 8 steam soot blowing systems for the #2 boiler economizer was completed and commissioned on November 15, 2023, the full-load test showed that the exhaust gas temperature decreased from 175–190°C (before August 6, 2024, when the desulfurization system was not fully put into operation) to approximately 145–155°C. The energy-saving effect after the modification was highly successful.