Raising the pressure: supercritical boilers

What is a supercritical boiler, and why are their deployments growing?


Dear Control Engineering: Looking at the article about new ultra-supercritical power plants, I have to ask what supercritical means, and why it matters.

If you think of what water looks like in a boiling pot, steam forms in bubbles in the water and rise to the surface. If the pressure in the boiler is higher than 3,200 psi, bubbles cannot form in the water, so the water converts directly to steam without conventional boiling. Ultra-supercritical boilers use pressures in the 4,500 psi range. Typically these are used in coal-fired power plants where the whole idea of using such high pressures is to gain efficiency. The higher the pressure, the higher the efficiency.

However, there are limits. Given the temperatures and pressures involved, the stress on the boiler is enormous. Practical deployments of supercritical plants capable of base loading have been relatively recent since boilers require materials and construction methods that are still being developed. The process of forcing feedwater into a boiler is also a challenge and requires proportionally larger turbines. Regulating steam production requires more sophisticated control systems which are also improving along with the construction methods. (Read an article about controlling such plants.)

Nonetheless, the desire for greater efficiency, here measured as kilowatt hours per ton of coal, is a worthwhile goal.

--Peter Welander, pwelander@cfemedia.com

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Choosing controllers: PLCs, PACs, IPCs, DCS? What's best for your application?; Wireless trends; Design, integration; Manufacturing Day; Product Exclusive
Variable speed drives: Smooth, efficient, electrically quite motion control; Process control upgrades; Mobile intelligence; Product finalists: Vote now; Product Exclusives
Machine design tips: Pneumatic or electric; Software upgrades; Ethernet advantages; Additive manufacturing; Engineering Leaders; Product exclusives: PLC, HMI, IO
This article collection contains the 5 most referenced articles on improving the use of PID.
Learn how Industry 4.0 adds supply chain efficiency, optimizes pricing, improves quality, and more.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security

(copy 5)