While hard to imagine, supercritical boiler technology is almost 100 years old. Granted, it didn’t look anything like what it does today when Mark Benson first obtained a patent to convert water into steam at high-pressure levels in 1922. With recent technological advances in the power industry, power plants have increased in size in an effort to achieve the most efficiency & capacity possible to increase megawatts.
Today’s supercritical boilers burn pulverized coal and are considered once-through boilers, meaning that they do not require a drum to separate steam from water. Rather than boiling water to produce steam and then using that steam to turn a plant’s turbine, a supercritical boiler operates at such high pressure (3,208 psi/221.2 bar or above) that the fluid matrix in it ceases to be liquid or gas.
Due to the size, configuration and poor circulation quality of supercritical boilers, a different chemical cleaning process became necessary. A more volatile process is required, where the chemistry is more efficient with less movement in its circulation, due to the tube walls and headers. Now, it’s common practice to use the hydrochloric acid method to obtain good cleaning results under the poor circulation conditions. Because hydrochloric acid is highly volatile, it’s useful in units that are difficult to fill, circulate and drain.
Again, due to the piping configuration and lack of steam drum, a high-pressure exhaustive steam blow method is the most efficient way to achieve proper start-up standards. This method goes up to, and sometimes exceeds, 1000 PSIG. This process is both dangerous and life-threatening, if not properly engineered by a reputable pre-commissioning cleaning company.
Advantage of Supercritical Boilers
Supercritical boilers’ ability to operate at much higher pressures and temperatures than subcritical broilers translates into noticeably better efficiency ratings. While subcritical boilers operate at an average of 34.3%, supercritical boilers are able to reach an efficiency of 38.5%. Improved plant efficiency also translates into reduced emissions, and each percentage point of efficiency improvement generally yields 2-3% less CO2. For all fossil fuel-fired plants, fuel often represents the largest operating cost. Supercritical plants offer a solution by reducing the amount of fuel needed to yield the required energy, providing a noticeable boost to the bottom line.
Why Choose B&W Energy Services
B&W Energy Services performs the pre-engineering and engineering for many of the most complex projects worldwide, and has done so for many years. Through our pioneering years of service we have gained great knowledge in exhaustive, high-pressure steam blow services and kept up with advancements in the power industry. Through trial and experience, we have developed the premier high-pressure, hydraulically controlled and quick opening valves that are required to effectively steam blow supercritical power plants. But it didn’t end there.
It became quite clear that intensive engineering would also be required to identify the heavy pipe supports needed for a safe execution of the steam-blowing event. B&W Energy Services took charge and developed the engineering plans required, and now safely executes steam blows on supercritical plants around the world.
When performing pre-commissioning cleaning on supercritical boilers, you need the highest level of knowledge available to support the project safely. Whether it’s chemical cleaning, steam blowing, AquaLazing, lube oil flushing, pulse flushing, or any other cleaning requirement–you can count on B&W Energy Services to make sure each project is designed properly, executed safely and performed by one contractor—ourselves.