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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This is slightly off attemoerator but still relevant question for Control engineers at a time when Advanced process control schemes are becoming more prevalent. The designs discussed here will apply to the reheater and superheater, but only the superheater will be mentioned for simplicity. 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.

Steam Temperature Control | Control Notes

Attemperator is a spray of attemperator in boiler to reduce the steam temperature that is limited as per boileer operational requirements. 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 While the numbers are moving in the right direction, there is still the opportunity for considerable improvement.

In essence, when boiler load is increasing, the spray water flow rate will be increased to counter the iin heat being transferred to the steam, and vice versa. Steam Temperature Controller Gain Scheduling. November 11, at March 20, at 8: Promoting, selling, recruiting, coursework and thesis posting is forbidden. This discussion will focus on steam temperature control through attemperation. Simple Steam Temperature Control.

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. Difference between attemperator and desuperheater thanks all, very informative comments and helps a lot.


One of the reasons biler superheaters and reheaters are not working as envisioned is because they were designed for operating criteria that never materialized. 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 This control loop should be tuned for the fastest possible response without overshoot, but even then the loop will respond relatively slowly due to the long dead time and time lag of the superheater.

Independent voice of the gas-turbine-based generation sector. Yet other systems e. 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. In the plant where I worked, the main and re-heat steam noiler control loop is cascade without feedforward demand.

September 17, at 6: In the few cases where it is necessary to spray to saturation, a simple temperature based limit cannot be used. Anderson next explained how attemperation works and what can go wrong with any desuperheater system, including the following:.

Anderson next explained how attemperation works and what can go wrong with any desuperheater system, including attemperator in boiler following:.


Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. Or at least the ones I put in had to.

attemperatir It is is very informative detail. Keeping steam temperature constant is also important for minimizing thermal stresses on the boiler and turbine. Fixed-orifice nozzles are not suitable for this service, in his opinion Fig Students Click Here Join Us!

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


See your Yokogawa user guide for how to do it. The plug and the seat are designed to create maximum water velocity at the nozzle edge point. Steam that can instead be used for the desalination plant.

If the spray water flow rate to the attemperator is atgemperator, a flow control loop can be implemented as a tertiary inner loop to provide very fast disturbance rejection.

Note that there is no drain between the attemperator and the superheater harps, so any leaking spray water expected from valve boilsr and tear must run into either the primary superheater 2 or secondary superheater, depending on which way the pipe slopes.

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The power industry lacks the skills to implement and maintain APC, and the cost benefits are just not there in many cases except perhaps for environmental controls. In Fig 7, there is no drain between the attemperator and the superheater 2 harps as in Fig 6.


August 24, at 2: Imran, From the information you gave me it is not possible to tell exactly what the problem is. Atemperator, here the pipe housing the attemperator is too short to permit adequate residence time for evaporation at high spray flows.

He said that use of a ring-style attemperator might reduce the downstream straight run by the equivalent boiled a few pipe diameters.

Download Now White Paper: The manufacturer will specify. The feedforward can be calibrated goiler measuring the extent of steam temperature deviation during load ramps. The initial spray is called Superheat spray. Digital transformation may be the most frequently misunderstood and misused term in business discourse today. With regards to the main steam ih to desuperheater outlet temperature cascade arrangement, is the inner loop here typically many times faster than the master loop?

Modern PID control blocks allow you to expose the tuning settings to be connected to external signals.