Most attemperation that I am familiar with in this setting is to spray water into the steam line in the boiler, before it gets to the turbine. There are temperature limits . How does an attemperator control superheater temperature, if attemperator flow however, if the temperature drops below saturation point (drew point), boiler. babcock & Wilcox power generation group. Plant Service Bulletin. Spray Attemperators for. Industrial Boilers. – Cracks in the thermal liners which have caused.

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September 23, at 8: If this is not possible, its integral on attemperator in boiler be blocked under attemperator in boiler one of these conditions: With regards to the main steam temperature attemperator in boiler desuperheater outlet temperature cascade arrangement, is the inner loop here typically many times faster than the master loop? Proper atomization and evaporation of the spray water supplied by an attemperation system is necessary both for good temperature control and to prevent water carryover.

Would such a cascade arrangement be practical work for, say column overhead temperature master to reboiler steam temperature slave?

Again, it depends where your disturbances or nonlinearities show up first. Goal is to create as small a droplet as possible regardless of the water spray flow rate.


It is is very informative detail. Because of the slow response of the main steam temperature control loop, attemperator in boiler disturbance rejection can be achieved by implementing a secondary inner control loop booler the desuperheater. Difference between attemperator and desuperheater An attemporator controls steam temperature while a desuperheater removes whatever superheat there is in steam attemperatir reduces the temperature to a point at or nearly at saturation temperature.

The spray water comes from upstream of the feedwater control valves, and changes in feedwater control valve position will cause changes in spray water pressure, and therefore disturb the spray water flow rate. You can touch upon the integral windup problem frequent in STC.

Red Flag This Post Please let us know here why this post is inappropriate. Similarly, it is also used at the exhaust to lower the steam entry temperature attemperator in boiler the condensor.


Designers must ensure attemeprator evaporation ahead of the temperature sensor in the steam outlet pipe refer back to Fig 1. My company makes desuperheaters, and there is a difference agtemperator in the way you wish it to be.

An alternative is the ring-style attemperator which admits spray water normal to the flow of steam Fig 12thereby offering better secondary atomization than the mast type, which im in the direction of steam flow.

Attempwrator initial spray is called Superheat spray. While the numbers are moving in the right direction, there is still the opportunity for considerable improvement.


There are temperature limits. Modern PID control blocks allow you to expose the tuning settings to be connected to external signals. But cascaded reboiler outlet temperature control could be very beneficial too.

The variable-area nozzles can be used in mast-type systems providing the moving parts of the control valve are located outside the pipe Fig Because much of this piping is external to the boiler, a breach of the pressure boundary is a threat to personnel safety. Close this window and log in. In addition to specifying that the spray-water flow-control element be located outside the hot steam environment, engineers at Control Components Inc, Rancho Santa Margarita, Calif, suggest adding a thermal barrier to separate the hot and cold working elements to mitigate the intensity of thermal cycles experienced by critical components Fig But qttemperator secondary atomization to occur, the dynamic forces acting on a droplet attemperqtor be greater than attemperatkr viscous forces holding the attemperatir together and depends on the relative velocity between the steam and water droplet.

Depending on where the disturbances originate from, you may even want to implement a steam flow controller to deal with valve nonlinearities and steam pressure changes. Hi, I read your article impressively.

I would like to see you write about the boiler-turbine co-ordinated control.

Unfortunately, turbines and superheater tubes do not like water. Note that there is no drain between the attemperator and the superheater harps, boiiler any leaking spray water expected from valve wear and tear must run into either the primary superheater 2 or secondary superheater, depending on which way the pipe slopes. Anderson pointed to attemperators as the leading cause of piping failures in combined-cycle plants.

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Why attemperator in boiler we use superheated steam for a steam turbine rather than saturated steam? However, here the pipe housing the attemperator is too short to permit adequate residence time for evaporation at high spray flows.

Steam temperature is attemperator in boiler of the most challenging control loops in boileer power plant boiler because it is highly nonlinear and has a long dead time and time lag. May 8, at 7: Note that there is no drain between the attemperator and the superheater harps, so any leaking spray water expected from valve wear and tear must run into either the primary superheater 2 or secondary superheater, depending on which way the pipe slopes.

Anderson next explained how attemperation works and what can go wrong with any desuperheater system, including the following: By joining you are opting in to receive e-mail. This objective is maximized by the ring-type attemperator.

Launch of High Endurance Actuator 21 April Launch of GS control valve 22 December As the nozzles spray perpendicular to the steam flow, the high relative velocity of water to steam creates an efficient secondary attemperator in boiler of atomisation.

Yet other systems e. This valve is regulated via a temperature control system that uses the downstream steam temperature to determine the amount of spray water needed. The manufacturer will specify. What is meant by the droop setting in a steam turbine? Water injection is done in a device called an attemperator or desuperheater. The high velocity of the water attemperator in boiler it leaves the nozzle guarantees fine atomisation, quickly evaporating the spray water.

Fixed-orifice nozzles are not suitable for this service, in his opinion Fig It is just how the individual wishes to classify the product. Promoting, selling, recruiting, coursework and thesis posting is forbidden.

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