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 17, at 6: With the increase in steam flow rate lagging behind fuel flow rate, the additional heat in the furnace can lead to large deviations in steam temperature.

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Please provide me more detailss…. Are your measurements and controller outputs ranged exactly the same as they were before the retrofit?

During boiler load ramps in turbine-following mode, the firing rate is changed first, followed by a change in steam flow rate a while later. The latter means it takes a relatively long time to respond to process upsets.

The ring design also ensures distribution of spray flow across the entire cross section of steam flow. This loop measures the desuperheater outlet temperature and manipulates the control valve position to match the desuperheater outlet temperature to its set point coming from the main steam temperature controller Figure 2. Modern PID control blocks allow you to expose the tuning settings to be connected to external signals. Students Click Here Join Us!

The gain of the desuperheater outlet temperature loop will be affected attemmperator by steam flow rate. This will have a negative impact on the stability of the main steam temperature control loop unless gain scheduling is implemented. The advantages of interstage attemperation, he said, tracing the flow of steam with a laser pointer, were reduced metal temperatures in the final superheater and reheater heat-transfer sections and prevention of carryover into the steam turbine.


However, in many cases spray water flow rate is not measured at the individual attemperators and this flow loop cannot be implemented. But for secondary atomization to occur, the dynamic forces acting on a droplet must be greater than the viscous forces holding the droplet together and depends on the relative velocity between the steam and water droplet.

However, you will likely also require some degree of feedback control to compensate for attemperstor variables such as different burners in use, boiler sooting, boilwr.


My company makes desuperheaters, and there is a difference only in the way you wish it to be. To present it in a block diagram, it will look similar as in the figure above, except you will have attemperattor function generator or f x blocks, one for each of the tuning settings. Or at least the ones I put in zttemperator to.

Anderson offered a simpler approach: An attemporator might be used between superheater zones in a multi-zone superheater attemperator in boiler or in a re-heater zone to control reheater outlet temperture.

An attemporator might be used between superheater zones in a multi-zone superheater boiler or in a re-heater zone to control reheater outlet temperture. Can you give the that logic which boile implemented to reduce this problem?

What is a condenser in a steam turbine? This is slightly off attemoerator but still relevant question attemperxtor Control engineers at a time when Advanced process control schemes are becoming more prevalent. September 23, at 8: Defective spray pattern Equipment malfunction—such as leaking valve, clogged or worn spray nozzles, failed nozzle, failed thermal liner in downstream piping Fig 2.

The Eng-Tips staff will check this out and take appropriate action. This arrangement is called cascade control. Hi, I read your article impressively. After separation from the boiler water in the drum, the steam is superheated to improve the thermal attemperator in boiler of the boiler-turbine unit.


Improper design, operation, maintenance, and control logic for interstage attemperators, in particular, have been associated with a wide range of problems—the most serious being cracking of downstream piping. Thank you for helping keep Eng-Tips Forums free from inappropriate posts. Karthi, You bring up a good point. Steam Temperature Control September 8, Designers must ensure total evaporation ahead of the temperature sensor in the steam outlet pipe refer back to Fig 1.

Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. Fig 14 presents the details. With attemperator to the main steam temperature to desuperheater outlet temperature cascade arrangement, is the inner loop here typically many times faster than the master loop? Final desuperheaters are not intended for use after startup. The feedforward can be calibrated by measuring the extent of bojler temperature deviation during load ramps.

In Fig 5, the long runs of piping connecting primary and secondary superheaters and reheaters have only one drain each.

It is an excellent source of technical information on boiler controls. The manufacturer will specify.

This page may be out of date. There are temperature limits. Water injection is done in a device called an attemperator or desuperheater. September 18, at 4: Mail will not be published required. I’ll agree that desuperheaters are usually used to reduce superheated steam temperatures to just above saturation but you could just as easily change the temperature set-point to anything you want couldn’t you? While the numbers are moving in the right direction, there is still the opportunity for considerable improvement.

Again, it depends where your disturbances or nonlinearities show up first.