steamconditioning- & turbine bypass valves · it routes high pressure and high temperature...

_TECpress

1

TECartec GmbH * Am Heidering 7a * D-16515 Oranienburg * +493301/2032-60 * [email protected]

STEAM CONDITIONING- & TURBINE BYPASS VALVES

mailto:[email protected]

_TECpress

2


What is an HP Turbine Bypass Valve?

It routes high pressure and high temperature steam around the HP Turbine, from the main steam line typically to the cold reheat line. In doing so, the HP turbine bypass valve must perform both, pressure

reduction of the life steam as well as temperature control.

Pressure reduction is accomplished by a multi-stage low-noise trim within the valve body. The inlet pressure is controlled by an upstream pressure controller, signaling the valve to modulate to maintain the pressure at the required set point. Alternatively the valve can accept a digital signal to quickly modulate and control the pressure.

Temperature control is accomplished through the addition of cooling water to the steam flow to reduce the specific enthalpy of the steam (a process called desuperheating). A separate water control valve supplies the correct amount of spray water to the desuperheating mechanism within the steam conditioning valve. A downstream temperature transmitter typically operates by applying a feed-forward algorithm within the DCS to dictate the amount of water injected into the steam.

TECpress with steam-assisted water injection and TECpress HT with up to 40 individually controlled

spray nozzles in the outlet section. Note: the outlet section can be substantially larger in diameter than the inlet. This is typically the case for LP Turbine Bypass Valves.

Typical Applications for HRSG HT-Desuperheaters and TECpress Turbine Bypass Valves in a CCPP


_TECpress

3


Combined Pressure Reduction and Desuperheating ensure Maximum Performance and Reliability

The TECpress range of valves is primarily used in utility power plants for Steam Turbine Bypass to Cold Reheat but it also can be utilized for similar desuperheating applications in Process Applications.

- As reliability and accurate performance are paramount to the operation and safety of the plant, the selection of the TECpress for turbine bypass applications is highly beneficial. By utilizing the energy of high velocity steam in a Laval nozzle to mix with small cooling water droplets, an

efficient temperature control can be assured.

- Alternatively, for very large spray water amount requirements and extremely high steam temperatures the TECpress can be equipped with a ring injection system (TECtemp HT R). This system with no moving parts in the heat affected zone is used in supercritical and ultra-supercritical power plants.

- The inlet steam pressure reduction takes place independently of the water injection. This avoids

potential excessively high thermal stresses caused by temperature differentials between the cooling water and superheated steam. This guarantees a long life time of all control elements and avoids costly downtimes.

TECpress

TECtemp

multi nozzle desuperheater

TECsteam

Steam-assisted desuperheater

TECtemp HT R

multi nozzle radial desuperheater


_TECpress

4


Requirements for a reliable high performance Turbine Bypass System

Resistance to Thermal Shock and Fatigue

- The Bypass Valve will repeatedly be subject to severe thermal stresses and very frequent cycling

of the plant during its lifetime.

- TECartec is using only forged, and fully machined high temperature-resistant alloys for the pressure containment, and no crack-sensitive castings.

- The valve body is contoured without any abrupt changes in wall thickness, therefore minimizing

thermal stresses.

- Valve body and trim are both designed to assure reliable and safe operation.

Maximizing Power Output of Plant and reduced Valve Maintenance

- Longtime seat tightness is provided to prevent steam leakage.

- Severe seat leakage results in excessive maintenance, costly plant shutdowns and financial losses.

Must handle severe Pressure Drops

The Bypass Valve will control pressure drops of greater than 100 bar. The valve trim has sufficient pressure reduction stages to prevent erosive wear, excessive vibration and noise. We can install up to 8 pressure reduction stages in our cage design.

Depending on the application our pressure reducing stages are built in different ways:

Stacked cages

Stacked disc design with cage

Advantages of the TECartec pressure reduction design:

- Easy maintenance due to threaded design

- No welded-in seats

- No special tools required

- Rugged and reliable design

- Max. SPL<=85dBA (1m distance)


_TECpress

5


Bonnet Executions for Steam Conditioning and Turbine Bypass Valves

Standard Bolted Bonnet

The simple bolted bonnet cover (used for lower pressure class…….) can easily be removed. It represents the second most important boundary of a pressurized valve.

TECartec’s bonnet is made of forged material, and is fully machined.

For the sealing we use a special graphite ring,

tightened down by alloyed high temperature resistant stretch bolts.

Figure 4. Standard bolted bonnet (cover)

Pressure Seal Bonnet (UHDE Bretschneider)

Pressure seal bonnets are self–sealing (once they

are pre-stressed at a defined torque) and have successfully been used in high-pressure and high temperature environments in power and process plants for many years. After asbestos gaskets were banned from usage the industry adopted successfully highly compressed graphite cap seals. These special rings have proven their viability since

many years and are available in several special versions, for example with metal reinforcement or with stainless steel caps for certain special

applications. This bonnet concept stands out mainly by its reliability, high p&T-rating, ease of use, safety aspects and its service friendliness.

TECartec VSS

This is a pressure seal bonnet design which has

been developed for excessively high pressures and temperatures. We use this patented design for supercritical and ultra-supercritical conditions in process and power plants.

The gasket is located in the direct flow of force. Changing pressures inside of the valve have no impact on the special gasket. Typically we use a specially coated metal C-ring. This ring doesn’t undergo oxidation due to the hot gas as this would be the case for common graphite rings.


_TECpress

6


TECpress with integral water injection (Standard)

Steam Conditioning Valve or Turbine Bypass System(HP, IP, LP)

Main Characteristics of our Standard Execution

The TECpress Steam Conditioning Valve is capable of controlling pressure and temperature simultaneously.

Due to an intricate pressure reducing arrangement the steam pressure is reduced subcritical at all load levels.

Silencers are used to keep sound pressure levels below the typically specified level of 85dBA with an insulation thickness of 100mm (4”) of heavy density Rockwool.

Water doesn’t get injected in areas where high temperature differentials (water/steam) could damage the mechanical components.

Seat tightness is at least ANSI Class V.

Specifics

- design according to PED, DIN, EN 12952, ASME B16.34

- safety function according to TRD421, AD2000 A2

- angle valve design execution

- globe valve design execution

- forged, fully machined and welded body design (we do not use castings for these severe service

conditions)

- subcritical pressure reduction over the entire control range

- desuperheating takes place immediately after the pressure reduction, with either…

o a steam-assisted nozzle, or o a number of individually controlled nozzles (up to 40 pcs. for a TBV) in the outlet of the

valve, and with minimal flow disturbance and pressure loss in the steam line. See TECpress HT picture further down.

o very fine and uniform distribution of spray droplets across the entire pipe section, resulting in short droplet evaporation time and distance

o drastically reduced droplet impingement risk compared to conventional systems

- connections:

o Flanges acc. DIN, ANSI, JIS o BWE

- actuation: o Pneumatic o Electrical o Hydraulic (incl. hydraulic actuator, power supply unit, and electronic controls)


_TECpress

7


TECpress HT R TECtemp HT Spray Water Control Unit

This HP/IP Turbine Bypass Valve comes with the patented TECtemp HT Cooler Unit installed immediately

after the steam pressure reduction. It is specifically designed for Supercritical and Ultra-supercritical

installations with large spray water amounts, and medium to very large steam outlet pipelines, and

where controlled water-injection and atomization resulting in short evaporation lengths are required.

TECartec offers different desuperheating solutions (probe-style, ring-style, ring-style with ventury spray

body), all with absolutely no moving parts in the heat-affected zone, and depending on the particular

design with up to 40 individually controlled spray nozzles of different size and spraying pattern/capacity.

The pressure loss in the steam line due to these nozzles is max. 0.1bar, way less than with conventional

probe-style desuperheaters.

This design allows to generate the finest cooling water droplet size spectrum and allows to evaporate

the spray water over the shortest possible distance, without impinging on the very sensitive pipe wall.

Turbine bypass valve TECpress HT with TECtemp HT desuperheater


_TECpress

8


Main Parts and Materials (x : recommended Spare Parts)

ITEM

Parts and Materials

PART MATERIAL

1 Body Carbon Steel, Chrome - Moly

2 Concentric Reducer Carbon Steel, Chrome - Moly

3 Desuperheated Steam Outlet Carbon Steel, Chrome - Moly

4 Bonnet Carbon Steel, Chrome - Moly

5 Gland Flange Stainless Steel

6 Gland Bushing - x Stainless Steel

7 Stem - x Stainless Steel, Inconel®

8 Perforated Cage – x Stainless Steel with Chrome Plating and Nitriding

9 Pressure Reduction Cages - x Stainless Steel with Chrome Plating and Nitriding

10 Perforated Disc Stainless Steel with Chrome Plating and Nitriding

11 Desuperheating Unit

(Nozzle Body, Nozzle Housing, Cooling Water Inlet)

Carbon Steel, Chrome - Moly

12 Base Ring Alloyed Special Steel

13 Gasket - x Pure Graphite 99,85% (1,2;1,4;1,6)

14 Graphite Seal Rings - x Pure Graphite 99,85% (1,2;1,4;1,6)

15 Graphite Seal Rings - x Pure Graphite 99,85% (1,2;1,4;1,6)

16 Seal ring with insert - x Pure Graphite 99,85% (1,2;1,4;1,6) with

Stainless Steel Ring

17 Studbolt - x Alloyed Special Steel

18 Hexnut - x Alloyed Special Steel

19 Studbolt - x Alloyed Special Steel

20 Hexnut - x Alloyed Special Steel

21 Cagenut Alloyed Special Steel

*Common materials: typically 13CrMo44, 10CrMo910, F91, F92 (other materials on request)


_TECpress

9


Dimensions

Body Size Stem & Seat Packing Seal Stroke

No. E

[mm]

H

[mm]

G

[mm]

Inlet F

DN/ASME

Outlet I

DN/ASME

Seat A

[mm]

Stem B

[mm]

Plug Stem D

[mm]

Inner Diameter

[mm]

Outer Diameter

[mm]

C

[mm]

1 150 60 70

25 / 1"

32 / 1 ¼" 40 / 1 ½"

50 / 2"

40 / 1 ½"

50 / 2" 65 / -

80 / 3"

12 20 18 18 38

30

14 20 18 18 38

17 20 18 18 38

20 23 18 18 38

22 25 18 18 38

25 28 20 20 32

27 30 20 20 32

2 250 140 110

50 / 2" 65 / -

80 / 3"

100 / 4"

80 / 3" 100 / 4"

150 / 6"

200 / 8"

32 35 20 20 32

70

37 40 25 25 41

42 45 25 25 41

47 50 40 40 60

57 60 40 40 60

67 70 40 40 60

3 400 200 150

100 / 4"

150 / 6"

200 / 8"

150 / 6"

200 / 8" 250 / 10"

300 / 12"

77 80 50 50 70

120

87 90 50 50 70

97 100 50 50 70

106 110 60 60 80

116 120 60 60 80

4 500 380 200 200 / 8"

250 / 10"

250 / 10"

300 / 12" 350 / 14"

126 130 70 70 90

170 136 140 70 70 90

146 150 70 70 90

156 160 70 70 90

5 530 420 215 300 / 12"

350 / 14"

350 / 14" 400 / 16"

450 / 18"

166 170 70 70 90

190 176 180 80 80 100

186 190 80 80 100

6 560 470 230 300 / 12"

350 / 14"

400 / 16" 450 / 18"

500 / 20"

196 200 80 80 100

200 206 210 80 80 100

216 220 80 80 100

7 600 490 250 350 / 14" 400 / 16"

450 / 18"

450 / 18" 500 / 20"

600 / 24"

226 230 100 100 100

200 236 240 100 100 120

246 250 100 100 120


_TECpress

10


SCV/TBV/DSH Product Selection

APPLICATION Service TECartec Product Remarks

Process Steam Pressure & Temp. Control TECpress

Low- int.med. Temp. Contr. TECtemp

Elevated Temp. Controls TECtemp Boiler Environment

Super- and Ultrasupercritical TECtemp HT L, HT R

Boiler Interstage Attemperation

Steam-assisted DSH TECsteam Temp. contr. close to Saturation

Turbine Bypass HP, Super- and Ultrasupercritical

TECpress, TECpress HT R

IP/LP TECpress, TECpress HT R/HT L

Hydr. Power Unit & Controls

Depending on Application Contact TECartec

Condenser Dump Low to high Loads TECpress (and Dumptube)

Spraywater Control Contact TECartec

Spraywater Isolation Contact TECartec

Filter Contact TECartec

Water Valves and Auxiliary Steam Applications

TECartec manufactures a considerable selection of special high pressure control valves for liquids (

mainly for water), steam, oil and gas. This also includes special coated metal-seated ball valves, gate

valves, and severe service control valves. They are used for spray water control (in conjunction with DSH,

SCV and TBV), drain service (including two-phase flow) and many other applications in power and

process plants, as for example…

- Feedwater control

- Spraywater control for superheater and reheater applications

- Pegging steam in deaerators

- Deaerator level control

- Extraction applications

- Boiler level control and blow-down valves

- Heater drain control valves

- Etc.


_TECpress

11


Engineering, R&D

TECartec’s advanced and unique designs display a significant degree of innovation and originality,

incorporating several decades of valve know-how and practical experience in the power and process

industries. Our field service team shares their long experience (based on our own and other makers’

valves) with the R&D group and feeds important inputs from our customers to develop solutions

which provide an optimum performance, reliability, and best possible return of investment to the users

of our products. Many of our unique designs have been awarded patents.

FEA of forged Valve Body CAD and DDS Designing

Example 1: The TECtemp HT multi nozzle turbine bypass design for temperatures above 520C has no moving parts at all in the hot area and is good up to 720C. The spray characteristics of the TECtemp HT design is substantially better than what for example commonly used spring-loaded nozzles are capable to achieve under best conditions.

Below picture: Uniform Temp. Distribution around the Pipe Periphery, with cooler sections rapidly moving towards the center of the pipe (blue). Notice: Cold Water Droplets don’t impinge on the pipe wall.

Large Pipe DN: Temperature Distribution shortly after Injection Droplet -Path and -Velocity


_TECpress

12


Example 3: Waterinjection pipes (spray cooling) with Thermal Liners (TECartec / MHI-Hitachi) in a

Supercritical Power Plant. Replacement of a competitive desuperheater design. This DSH can also be

used in conjunction with the Turbine Bypass TECpress.

Example 4: Interstage Attemperation with TECtemp HT Desuperheaters in a Supercritical HRSG. This

DSH with no moving parts in the heat-affected zone is good for up to 750C, and can solve many of the

current problems the industry experiences with conventional DSHs.

HRSG TECtemp HT L

Patented High Temp. DSH for HRSG interstage attemperation

Example 2: Exhaust Gas Cooling in HRSG Arrangement of several patented Desuperheaters TECtemp HT after a Gasturbine, at the inlet to the HRSG. Notice the Dropletsize-Reduction after a very short Distance. No Impingement on

the HRSG walls!


_TECpress

13


Manufacturing / Stock

We are equipped with state-of-the-art CNC machines to manufacture, weld, assemble and test all of our

products in-house.

We also keep a sizable inventory of all potential spare parts, and raw materials in various high temperature

grades.

All welding work and PWHT is done internally

Machining of all components in our factory in Oranienburg near Berlin

In-house programming on CNC machines


_TECpress

14


TECpress Installations

Safety Function Test Equipment acc. TRD421

for Turbine Bypass System

TECpress Turbine Bypass during start-up phase

Hydraulic Power Supply Unit for Turbine Bypass

HT Desuperheater / TBV


_TECpress

15


TECtemp HT Desuperheater installation examples

Nozzle Head for Turbine Bypass Valve (min. 3 pcs. in a pipe)

No

Multi Nozzle Venturi Desuperheater TECtemp HT V


_TECpress

16


TEC artec GmbH Am Heidering 7a | D-16515 Oranienburg | [email protected] P. +49 (0)3301 20 32-60 | F. +49 (0)3301 20 32-70 | www.tec-artec.de GPS: 52.773151°, 13.262119°

AVK Valves Korea Co., Ltd. Korea fon: +82 51 664 8808 e-mail: [email protected]

World Valve B.V. fon: +31 5353 81 295 email: [email protected]

AVK Flow Control Singapore Pte. Limited fon: +65 6214 0248 e-mail: [email protected]

Orbinox India Pvt Ltd Indien fon: +91 422 669 1261 e-mail: [email protected]

AVK Industrial Pty Ltd Australien fon: +61 8 8262 8885 e-mail: [email protected]

InterApp Italiana S.r.l. Italien fon: +39 (0)2 33 93 71 e-mail: [email protected]

AVK Flow Control Middle East fon: +966 2637 1570 e-mail: [email protected]

KITRO Pars Corporation Iran fon: +98 21 220 53 563-4 Ext.: 105 email: [email protected]

AVK Southern Africa fon: + 27 1265 38 313 e-mail: [email protected]

Bickel & Wolf GmbH Austria fon: +43 2231 67390 e-mail: [email protected]













steamconditioning- & turbine bypass valves · it routes high pressure and high temperature...

Documents