A Long Experience in Energy Equipment and one Goal: The Customer s Satisfaction. CHOKE. Control Valves

Transcription

1 A Long Experience in Energy Equipment and one Goal: The Customer s Satisfaction. CHOKE Control Valves

2 ENERGY NEEDS CONTROL Choke valves are required to handle some of the most demanding operating conditions: improved resistance to erosion due to sand and other particulate matter entrained in fluids; pressure drops of up to 500 bar, with erosive fluid mixtures of hydrocarbon liquids and gases, sea water and sand; vibrations, noise and erosion of the valve body which affects its pressure resistance; erosion of the valve trim and downstream pipework, if not designed correctly; flows high uncontrolled velocities due to sand and solid components can result, in the fluid, shock waves/turbulence interaction leading to dramatic noise levels and vibrations; to accommodate significant changes in well operating conditions over time; in addition we must take of controls the increasingly demanding and challenging enviroments Disks stack of multistage trim, controls flowing velocities throught out the valve by forcing the process fluid to follow a tortuous path of right angle turns. The resistance to flow provided by these turns (or stages) limits the trim exit velocity to a safe level, regardless of the pressure drop. These kind of choke valves eliminates problems resulting from excessive fluid velocities such as trim and body erosion, noise, vibration and poor process control. The fluid velocities within the trim of Valvitalia choke valves are typically ⅓ to ¼ that of conventional single stage trims. Velocity control protects the trim from erosion and increases the trim life many fold. The rate of erosion has been shown to be proportional to the velocity of the fluid by the third to fifth power, which suggests that erosion rate would be reduced by eight times if the fluid velocity is reduced by half based on a proportionality to the third power. CONVENTIONAL SINGLE STAGE VALVE VELOCITY MPL CHOKE VELOCITY CONTROL PROFILE 2

3 MULTISTAGE DESIGN To limit fluid velocity throughout the valve trim and to drastically reduce the erosive effects of the sand, a multistage valve design uses a stack of disks, which incorporate a labyrinth path flow pattern by means of many right-angle turns in each disk. The velocity of all fluid components, solids included, is cut by at least 50% compared to single-stage plug and drilled cage designs. Being the rate of erosion proportional to fluid velocity by the third to fifth power, the erosion rate would be reduced by 10 to 30 times about. The use of tungsten carbide trim throughout, the erosive effects of the sand are minimized. In addition,long valve stroke increases rangeability and improves the controllability,so that flow set points can be maintained and the changes in operating conditions can be accommodated over time. The trims of these valves are also characterized by different design of individual disk tortuous paths. Flowrate per disk in one group is higher or lower than in a disk in another group. The benefit of this characterization lies in the ability to maintain larger distance between the plug and the seat at low flowrates ; pressure reduction within the tortuous path is therefore the same as that obtained by a throttling process through the small plug/disk annular clearance. The trim of Valvitalia choke valves have large flow passages to handle solids and dirty fluids with no risk of clogging The use of this multistage valve technology, combined with top efficient materials of construction has been absolutely successful. Valve life was proved to be up to 10 times greater than was previously experienced 3

4 Choke Valve PART LIST Item Part name 1 BODY 2 BONNET 3 STEM 4 BODY STUD 5 BODY NUT 6 BODY GASKET 7 PIN 8 CAGE 9 PLUG 10 SEAT 11 SEAT GASKET 13 PACKING FLANGE 14 PACKING STUD 15 PACKING NUT 16 PACKING FOLLOWER 30 SEAL RING 40 SEAT RING 41 SOFT INSERT 42 O-RING O-RING CLAMPING RING 46 STEM CONNECTOR 47 SCREW 80 DISK ASSEMBLY MAIN FEATURES body (angle / straight) sizes : from 1 1/2 through 10 as outlined in Cv table connections : flanged according to API and ANSI std ratings : API up to ANSI up to 4500 bonnet joint : flanged materials : A105,AISI4130,AISI 316 -duplex internal coating inconel 625 where necessary trim ports and travels : see Cv table trim style : multistage plug : unbalanced / balanced, seal rings protected by wiper rings stage number : up to 8 min flow passage : 25 mm 2 4

5 flow characteristic : modified linear, linear, modified equal flow direction : to close materials : disk stack and seat insert = tungsten carbide plug = tungsten carbide or 316 stellited stem = 17-4-PH or XM19 actuators pneumatic diaphragm or piston, electric, handwheel operator All the accessories for a reliable and safe operation of the process are available SIZES AND CAPACITY Trim size Body sizes Seat diameter (mm) Travel (mm) MPL trim Rated C v Variable MPL trim 1 1 1/2, 2, ,5 2, 3, , 4, ,5 4, 5, , 6, , 8, , 8, 10" F L 0,96 0,97 x T 0,87 0,91 Sizing factors MPL trim x FZ 0,78 0,92 F d 0,04 0,04 - Different C v available for numbers of stages / turns of the trim MPL and Variable MPL trim 5

6 - The Customer s Satisfaction. VALVITALIA S.p.A. Headquarter: Via Tortona, Rivanazzano (PV) Italy Ph: Fax: info@valvitalia.com Busto Arsizio (VA) Office VALVITALIA S.p.A. CONTROL VALVES DIVISION Via Mazzini, Busto Arsizio (VA) Italy Ph: Fax: info.tgt@valvitalia.com Padova Plant VALVITALIA S.p.A. - SYSTEMS DIVISION Via Campolongo, Due Carrare (PD) Italy Ph: Fax: info.tgt@valvitalia.com Vicenza Plant VALVITALIA S.p.A. - VITAS DIVISION VITAS Plant: Via Soastene, Brendola (VI) VITAS Offices: Via Olmo, 31/ Altavilla Vicentina (VI) Italy Ph: Fax: info.vitas@valvitalia.com Piacenza Plant TECNOFORGE S.p.A. Via Emilia Pavese, CastelSanGiovanni (PC) Italy Ph: Fax: tecfor@tecfor.it Internet: Arena Plant TECNOFORGE S.p.A. Via Stazione, Arena Po (PV) Italy Ph: Fax: tecfor@tecfor.it Internet: China Plant VALVITALIA CHINA VALVES CO.LTD. (Suzhou) Wujiang Econimic Development Zone - Jiangshu Province - China Ph: Fax: info.china@valvitalia.com Rev.0 6