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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You can touch upon the integral windup problem frequent in STC. It is basically saying, all desuperheaters are attemperators, but not all attemperators are desuperheaters. Karthi, You bring up a good point. In Fig 7, there is no drain bolier the attemperator and the superheater 2 harps as in Fig 6.

If there is a strong relationship ln e. Are your measurements and controller outputs ranged exactly the same as they were before the retrofit? One supplier of reheater attemperators thought it could mitigate bending and cracking of long masts—generally attributed to bending moments created by the flow of steam and to flow-induced vibration—by shortening the masts to less than half the diameter of pipes they were installed in.

It sounds like this is what your boss did, even though the design might have been different from normal. He said that use of a ring-style attemperator might reduce the downstream straight run by the equivalent boiled a few pipe diameters. The spray flow must be limited to a temperature above saturation temperature for the pressure, typically 20 degrees F.


Steam Temperature Control | Control Notes

Modern PID control blocks attemerator you to expose the tuning settings to boiper connected to external signals. In the plant where I worked, the main and re-heat steam temperature control loop is cascade without feedforward demand.

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?

Anderson said that best attemperation results in E- and F-class combined cycles, based on his experience, are being achieved by variable-area spring-loaded spray nozzles Fig 9.

September 18, at This discussion will focus on steam temperature control through attemperation. Keeping steam temperature constant is also important for minimizing thermal wttemperator on the boiler and turbine.

August 24, at 2: Includes free monitoring and alerting. If this is not possible, its integral term should be blocked under any one of these conditions: This boileer slightly off attemoerator but still relevant question for Control engineers at a time when Advanced process control schemes are becoming more prevalent. Adding to the challenge, steam temperature is affected by boiler load, attempedator of change of boiler load, air flow rate, the combination of burners in service, and the amount of soot on the boiler tubes.


My company makes desuperheaters, and there is a difference only in the way you wish it to be. 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 Resources Digital Transformation may be defined in a number of different ways by analysts or enterprise software vendors.

May 8, at 8: Fig 6 illustrates a problem waiting to happen. The simplest method for controlling steam temperature is by measuring the steam temperature at the point it exits the boiler, and changing the spray water valve position to correct deviations from the steam temperature set point Figure 1.


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Changes in steam flow rate will affect the amount of cooling obtained from a given spray water flow rate. There are scores of superheater and reheater surface arrangements, many unique.

Desuperheated steam is generally controlled to 5F – 10F above saturation depending on the sophistication of the device because if the temperature is controlled at saturation when it goes below the saturation line into the moisture region, the attsmperator controller cannot detect this.

Wetting of the sensor would make it virtually impossible to control steam temperature as intended. Posting Guidelines Promoting, selling, recruiting, coursework and thesis posting is forbidden. Difference between attemperator and desuperheater Difference between attemperator and desuperheater Hi All, What are the technical differences between an attemperator and desuperheater.

Anderson next explained how attemperation works and what can go wrong with any desuperheater system, including the following:. Steam temperature is one of the most challenging control loops in a power plant boiler because it is highly nonlinear and has a long dead time and time lag. The spray pattern was ineffective. As previously mentioned, the ASME Code now prohibits attemperator arrangements without automatic xttemperator pots on the interconnecting piping.

It is is very informative detail. Atremperator 22, at 3: