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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Attemperator performance is an area that needs some attention. Jacques, Attemperatof you for article, curious to know how I can implement gain scheduling in Yokogawa. Changes in steam flow rate will affect the amount of cooling obtained from a given spray water flow rate. In the few cases where it is necessary to spray to saturation, a simple temperature based limit cannot be used.


The Eng-Tips staff will check this out and take appropriate action. There are scores of superheater and reheater surface arrangements, many unique. But cascaded reboiler outlet temperature control could be very beneficial too. Defense manufacturing is all about project manufacturing and project accounting.


There are temperature limits. Anderson next explained how attemperation works and what can attemperztor wrong with any desuperheater system, including the following: It complies with all existing standards and is always pressure tested hoiler both the steam side as well as the water side.

See your Yokogawa user guide for how to do it. Hi, I read your article impressively. Steam Temperature Control September 8, Difference between attemperator and desuperheater An attemporator controls steam temperature while a desuperheater removes whatever superheat there is in steam and reduces the temperature to a point at or nearly at saturation temperature.


The disadvantages include the potential for carryover of water into piping and tube bundles harpsand the significant distance of the measured setpoint from the spray-water injection point.

Modern PID control blocks allow you to expose the tuning settings to be connected to external signals. Variable-area nozzles offer this capability, fixed-orifice nozzles do not. 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. Yet other systems e. Adding to the challenge, steam temperature is affected by boiler load, rate of change of boiler load, air flow rate, the combination of burners in service, and the amount of soot on the boiler tubes.

Steam AttemperatorAttemperation is the primary technique used for controlling the degree of superheat in a boiler.

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 temperature controller cannot detect this. Why attemperator in boiler we use superheated steam for a steam turbine rather than saturated steam?

However, you will likely also require some degree of feedback control to compensate for other variables such as different burners in use, boiler sooting, etc. I think the ‘key’ is Fisher’s in statement in the header ” Overshoot the desired outlet temperature.


Difference between attemperator and desuperheater It probably is. A gain scheduler should be implemented to adjust the controller settings according to unit load. Improper design, operation, maintenance, and control logic for interstage attemperatkr, in particular, have been associated with a wide range of problems—the most serious being cracking of downstream piping. There are temperature limits for the boiler tubes, and the turbine inlet.

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May 8, at 8: This is slightly off attemoerator but still relevant question for Control engineers at a time when Advanced process control schemes are becoming more prevalent. January 24, at Instead, it will accumulate below the lower headers and possibly flow up into the harps—a condition conducive to extensive tube failures.

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

The time to achieve complete evaporation depends on the total surface area of the water injected and is proportional to the square of the droplet diameter. If you have disturbances affecting your reboiler, then yes, consider using cascade control. This discussion will focus on steam temperature control through attemperation.

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