Product - BE Boiler Start-up Valve

​Once-through boilers require a minimum evaporator flow to cool the boiler tubes during start-up (minimum evaporator flow for spiral wound evaporators is approximately 30%). A recirculation system recirculates water out of the water separator back into the feedwater tank or to the economiser/evaporator to ensure the minimum evaporator flow. Different layouts of the recirculation system exist, recirculation of the water from the separator back to the feed water tank and water recirculation from the separator back to the economiser inlet with a recirculation pump. In addition to the above operating modes the start-u​​p valves can be used during boiler-filling and evaporator (air) purging.This operating mode typically requires high flow at low differential pressure.​​​​​

Key features

Trim design
  • Seat room purging: The trim is designed with a control edge upstream of the seat which shuts off the flow path for potentially damaging particles before the plug reaches the seat.
  • Vena contracta separate from seat: In normal control mode the smallest flow area of the trim is downstream of the seat, keeping potential erosion away from the seat.
  • Controlled gradual flow diversion: In the critical high velocity area, special care is taken to achieve a gradually controlled flow diversion preventing erosive water steam mixture hitting trim surfaces with high velocity.
  • Anti-erosion coating on control surface: Proven, hard anti erosion coating to ensure long life time of the trim.
Flashing conditions

Flash​ing water is highly erosive if it hits body or trim parts with high velocity. This must be avoided by design or the parts which are hit must be erosion resistant.

An angle over-the-plug configuration with its straight outlet for the flashing steam is therefore the most favourable configuration. A rapid increase of flow diameter at the point where the medium expands, avoids erosion downstream of the valve.
In the Z-shaped valve body, an outlet cage is needed to protect the body. It is recommended to have a straight pipe run downstream of the valve because the flashing water will also erode pipe bends.

Debris

Boiler start-up valves often experience debris, because the water separator is typically the debris collector of the boiler. On the other hand the valve has to be absolutely tight for long operating periods. If the seat is only slightly damaged by debris which has been clamped between seat and plug, then continuous leakage of flashing water will quickly erode the seat further and increase the seat leakage. This will lead to severe damage of the valve. Therefore the trim design should prevent particles being trapped between seat and plug when the valve is closing.

​Benefits​

  • Specifically designed as a separator drain valve for supercritical boilers.
  • For operation with flashing water (saturated condition at the inlet).
  • Quick change trim for easy maintenance.
  • Seat area purging reduces particle damage.​
  • ​Angle and Z-shaped body design available.
  • For easy inspection and maintenance, none of the internals are welded or bolted to the body or bonnet.
  • Block tight according to MSS-SP61 or EN 12266-1 Class B.​​



​​Product specification

Design code
EN 12516-2, others upon request
Body style​
Angle type; Flow-to-close
Z-type, Flow-to-close
Fluid data range
Inlet: 320bar / 450°C; Outlet: 60bar / 300°C
Pipe connection
Butt-welding according to customer requirement
Other connection types upon request
Trim
Unbalanced, quick change trim
Actuation
Double-acting hydraulic actuator
Seat/stem tightness
EN 12266-1 Cl. B or MSS-SP61or ANSI/FCI 70.2 Cl. V
Serviceability
Replaceable stem/plug, seat, inlet cage, outlet cage (Z-type design)
Bolted bonnet
Options
Transition pieces for large pipe diameters and material compatibility
Orientation
Standard actuator vertical up, others upon request​






​Typical materials​


General information


Latest News

Unconventional support for the unconventional oil and gas industry
01 July 2019
INWED19
17 June 2019
IMI CCI showcases choke valve at DUG Rockies conference
04 June 2019
Jackie Hu appointed Divisional Managing Director of IMI Critical Engineering
07 March 2019
Roy Twite to succeed Mark Selway as Chief Executive of IMI plc
05 March 2019
IMI Critical holds Safety Summit
21 September 2018
New HSE handbook to help keep field service engineers safe
10 August 2018
Safety first at IMI Critical
31 July 2018
IMI InterAtiva’s Series RK Valves certified ‘fire-safe’
24 July 2018
IMI CCI participates at regional VPP Safety Summit
08 June 2018
Largest Romanian customer recommends IMI Remosa
10 May 2018
Lean success in IMI Critical back office functions
04 May 2018
Isolation valves adapted for Fluidised Catalytic Cracking applications
30 April 2018
IMI Critical Korea closes in on world-class LEAN performance
27 April 2018
IMI board tours IMI Critical businesses
25 April 2018
New positioner software tools from IMI STI
08 February 2018
Launch of Zero Backlash Scotch Yoke Mechanism
16 January 2018
IMI Critical Korea certified to sell actuators in Europe
20 September 2017
IMI Critical named ‘supplier of the year’ by Korea’s Doosan
19 September 2017
100th Valve Doctor graduates from IMI Critical
13 September 2017
Top HSE certification for IMI Critical’s California site
12 September 2017
Launch of High Endurance Actuator
21 April 2017
Launch of AB6350 valve
06 April 2017
Launch of 100DPC Multi-trim
17 March 2017
Launch of 840GS control valve
22 December 2016
IMI Critical to exhibit new technology at ADIPEC 2016
25 October 2016
New graduates join IMI Critical in four countries
22 September 2016
IMI Critical to take stand at ONS 2016 in Norway
16 August 2016
IMI Critical opens new China plant in Qingpu
27 July 2016
IMI CCI Korea celebrates 2,000 days of no “Lost Time Accident”
25 July 2016
Visit to IMI Z&J Germany by the Russian Economic Bureau from Bonn
11 July 2016
IMI Z&J Düren moves into modern offices
08 July 2016
IMI Critical Engineering forms strategic partnership with MRC Solberg & Andersen
05 April 2016
IMI Way Day 2016 date announced
01 March 2016
NEW IMI Eye – fourth edition
26 February 2016
IMI Critical co-locates China businesses
20 January 2016
IMI CCI Switzerland gains certification for new generation safety valves
18 December 2015
IMI Critical rise to Dragon challenge
30 November 2015
IMI STI achieves CRCC approval for new products
24 November 2015
IMI Truflo Marine Attend the Engineering Technology and Innovation Exhibition 2015
23 November 2015
IMI CCI Sweden secures new contracts on three continents
23 November 2015
IMI Critical Engineering appoints new petrochemicals head
05 November 2015
IMI CCI Czech Republic gains ‘Safe Enterprise’ certification
03 November 2015
IMI Critical announces 90mRMB investment in China
29 October 2015
IMI CCI SriCity wins regional safety award
27 October 2015
Key clients attend grand opening of new Aberdeen facility
23 October 2015
IMI companies ‘act as one’ to deliver for customer
02 October 2015
IMI CCI Sri City approved by NTPC
01 October 2015
IMI Critical Engineering showcases innovation at Valve World Expo Asia
28 September 2015
Nexen awards IMI Orton
25 September 2015
IMI Critical Engineering celebrates opening of new Jubail repair centre
23 September 2015
IMI Critical and IMI Precision join forces at Valve World Expo + Conference Asia 2015
21 September 2015
IMI Critical Engineering opening of new Jubail Repair Centre
18 September 2015
IMI CCI India manufactures first 1050MW turbine bypass valve
20 May 2015
Largest ever contract for IMI Critical Engineering
18 February 2015
New Houston facility opens
12 February 2015
IMI Critical completes acquisition of Bopp + Reuther
02 January 2015
IMI Critical takes family of brands to Valve World 2014
11 December 2014
IMI STI doubles size of Italian plant
20 October 2014

Downloads

​​​

Contacts

​​Global sales:
imicci.sales@imi-critical.com​​​
Product - BE Boiler Start-up Valve