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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Anderson offered a simpler approach: The manufacturer will specify. Again, it depends where your disturbances or nonlinearities show up first. There are scores of superheater and reheater surface arrangements, many unique. Steam that can instead be used for the bolier plant.
This is slightly off topic but still relevant question for Control engineers at a time when Advanced process control schemes are becoming more prevalent. After separation from the boiler water in the drum, the steam is superheated to improve the thermal efficiency of the boiler-turbine unit.
A proper liner is an important element in every desuperheating station. There are temperature limits. May 8, at 8: Hi, I read your article impressively.
ATTEMPERATOR IN BOILER PDF DOWNLOAD
One of the reasons many superheaters and reheaters are not working as envisioned is because they were atremperator for operating criteria attemperqtor never materialized. 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.
Steam AttemperatorAttemperation is the primary technique used for controlling the degree of superheat in a boiler. Why do we use dry steam in a steam turbine instead of saturated steam?
ATTEMPERATOR IN BOILER PDF DOWNLOAD
Moreover, how can I represent integrated gain scheduling feedback loop in the form of controller bolock diagram. Like superheat attemperatorsreheat attemperators are subject to the changes that are made in controlling main flue gas temperature in combustion. Reasons such as off-topic, duplicates, flames, illegal, vulgar, attemperator in boiler students posting their homework.
Attempetator page may be out of date. Join your peers on the Internet’s largest technical engineering professional community. Difference between attemperator and desuperheater It probably is. While the numbers are moving in the right direction, there is still the opportunity for considerable boilr. Steam temperatures above this level, even for brief periods of time, can shorten the usable life of the boiler.
Are your measurements and controller outputs ranged exactly the same as they were before the retrofit? 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.
Because much of this piping is external to the boiler, a breach of the pressure boundary is a threat to personnel safety.
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. Steam that can instead be used for the desalination plant. Step tests need to be done atetmperator low, medium, and high boilr loads, and optimal controller settings calculated at each load level.
In the plant where I worked, the main and re-heat steam temperature control loop is cascade without feedforward demand.
On paper, these desuperheaters having spray-water control-valve trim in the steam flow stream, offered excellent turndown by virtue of their numerous spray nozzles, Anderson said. You can touch upon the integral windup problem frequent in STC. In Fig 5, the long runs of piping connecting bokler and secondary superheaters and reheaters have only one drain each. Businesses find great customers attemperator in boiler targeting related topics.
The desuperheater outlet temperature control loop will provide a gradual recovery when this happens. August 11, at 9: To me it is more of a connotative thing rather than a denotative thing.
September 23, at 8: Red Flag This Post Please let us know here why this post is inappropriate. Several attemperator manufacturers have adopted this concept with satisfactory results.
November 11, at 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. Anderson offered a simpler approach: One of the reasons many superheaters and reheaters are not working as envisioned is because they were designed for operating criteria that never materialized.
The ring design also ensures distribution of spray flow across the entire cross section of steam flow. Modern PID control blocks allow you to expose the tuning settings to be connected to external signals.
Steam Temperature Control | Control Notes
In Fig 7, there is no drain between the attemperator and the superheater 2 harps as in Fig 6. Variable-area nozzles offer this capability, fixed-orifice nozzles do not.
Students Click Here Join Us! Because of the slow response of the main steam temperature control loop, improved disturbance rejection can be achieved by implementing a secondary inner control loop at the desuperheater.
Click Here to join Eng-Tips and talk with other members! This objective is maximized by the ring-type attemperator. 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.
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.