Your desuperheater system should be duly designed to grant the flexibility your power plant increasingly requires. This means that there is a need for proper understanding of the desuperheater system, how the different components operate, and how they should therefore be accurately designed.
Desuperheating is a severe service application, and as a result, your system may be likely to face an array of challenges. 3 common challenges include:
thermal shocks, unstable temperature control, and repeated or more frequent maintenance
Even facing just one of these challenges can upset your productivity and have a costly impact on the reliability of your system.
Thermal shocks are most likely caused by overspray due to the inability to temper steam correctly. This often happens during start-up, transients, and at steady-load operation. Desuperheater probes, liners, and steam piping are most susceptible to experiencing thermal quenching. Just one large overspray excursion can damage steam turbine internals and cause costly leaks that reduce turbine efficiency.
Desuperheaters are designed to keep the steam temperature control within a very strict range. The system is made up of 2 key components: the spraywater control valve and the spraywater nozzle. If
one of the two components, or both, are not suitably designed, they will negatively affect the process control.
For example, an oversized spraywater control valve, an incorrect type of spraywater nozzle, or simply a leaking spraywater control valve will make the temperature very difficult to control. This has the potential to cause overspray, increasing the risk for thermal shocks.
Regular maintenance is a very important activity. However, as you know maintenance can be costly and time consuming, especially when it occurs more frequently than anticipated or is entirely unforeseen. There is a negative domino effect created when individual parts of your system are not performing how they should.
For example, steam temperature control issues may be a symptom of thermal shocks, and in the worst-case scenario, may cause an unexpected shut down of your plant. Poorly designed and low
quality desuperheater systems will most likely be subject to premature wear and possible failures.
We recognise the desuperheater is not a stand-alone device, it is a system, and therefore must be designed as such, fitting your plant requirements.
The formula is quite simple. A system with zero leakage tight shut off spraywater control valves ensure steam pipes do not receive unrequested spraywater. This eliminates the risk of thermal
shocks in desuperheater elements, the Steam Pipe, and most importantly the downstream equipment.
A duly sized desuperheater will allow for proper and precise steam temperature control. As a result, maintenance time and cost will be reduced improving your plant reliability, enhancing your overall
productivity as well.
Pairing our consultative approach and 50 years of experience in the trouble shooting of severe service applications within steam and water cycles means we have the insight to help you further understand your desuperheater system’s performance, and in turn, find the solutions you need.
GESTRA’s German design and German quality ensure our solutions are developed with your plant in mind, ensuring the flexibility it requires, optimising productivity, improving reliability, and increasing
your plant profitability, too.
Spraywater control valves are quite often oversized. This results in very poor control performances which affect the steam temperature control, which at the same time, significantly reduces the valve lifetime as a result of working at low opening percentages.
Desuperheater atomizer nozzles, if not duly sized, will allow for the formation of large droplets. These droplets will be too substantial for complete vaporization, causing poor steam temperature control performance.
GESTRA’s desuperheater systems, with a wide range of spraywater control valves, lances, and steam coolers, have all been designed to ensure the flexibility your plant, granting optimal performance in variable operating conditions.
A high quality and duly designed desuperheater not only will boost your plant productivity and enhance flexibility, but also increase the reliability of your system even under the harshest operating conditions.
Zero water leakage in your steam pipe and proper desuperheating will significantly increase the longevity of your system, cutting on costly activities like responding to thermal shock.
A well designed and highly reliable GESTRA desuperheater system will cut your maintenance costs.
Operators sometimes are not aware that they are desuperheating almost all the time.
Early in start-up, throughout shutdown, and in operating modes that do not normally require steam attemperator, water flow to the desuperheater should be at zero.
Unfortunately, standard spraywater control valves are always leaking. Not only can this cause overspray, increasing the risk for thermal shocks, but if water is not then properly drained, the steam pipes will be subject to very dangerous water hammers.
GESTRA’s ZK control valve employs a combined isolation and control valve design, capable of granting a metal-to-metal zero leakage for several years of operation, achieving optimal performance and avoiding unforeseen system breakdowns.
By working with customers like you to understand their system, we have become trusted partners in tackling a range of challenges they have faced within their desuperheater systems, improving their system reliability, and improving their plant’s ability to meet demand.
See below how we have worked with our customers to achieve their power generation goals.
See how GESTRA helped a 1200MW CCGT power station resolve issues with the HP bypass station desuperheating system.
See how GESTRA helped a 400MW CCGT power station resolve their issues on the superheater desuperheating system.