Intermittent blowdown valve MPA / PA up to PN250 · GESTRA Steam Systems GESTRA Intermittent...

GESTRA Steam SystemsGESTRA

Intermittent blowdown valve MPA / PA up to PN250

�� Intermittent Intermittent BlowdownBlowdown Valve Valve � Special Design

-Radial Multi-stages Nozzle-Large Opening Area-Large Opening Area-Spring Closing Force

� Fail Safe Function� Boiler Pressure closes Valve� Pneumatic Actuator Possible� Function max 3 Sec� Function max. 3 Sec.� PN 40-250� DN 20-50

ENERGY TECHNOLOGY CO., LTD. �0-2721-3860


Boiler water discharge of different valves

ENERGY TECHNOLOGY CO., LTD. �0-2721-3860 Page 31 of 74


Automated intermittend blowdown system conventional



Bottom Blowdown Range up to PN250



The Benefits of the New GESTRA Intermittent Blowdown Valves

� Improved blowdown effectiveness through integrated pressure chamber in the outlet section of the body

G t ti ht th h dditi l i i b t th ki l� Greater tightness through additional wiper rings between the packing seals� Longer service life and availability through radial stage nozzle downstream of the valve seat� Insensitive to waterhammer through absence of large body cover� Reduced wear through new arrangement of the seals on the low pressure side

C i t t i l t ti f th k f t l ti th h l di t t b� Consistent implementation of the work safety regulations through novel distance tube� Quick and easy installation thanks to multifunction parts� Reduced maintenance and service effort through additional cup springs acting on the g p p g gcompression spring and through the possibility of tensioning the seals from outside� Better checking functionally through relief vent for leak detection from outside� Greater convenience through innovative clip fastening of the hand lever PA 46/47� Greater convenience through innovative clip fastening of the hand lever PA 46/47



Flash steam discharge/ventBlowdown receiver

Flash steam discharge/vent

Cooling Water

Hot waste waterCooling Water

Hot waste water

Mixed cooled water

Drain

ENERGY TECHNOLOGY CO., LTD. �0-2721-3860 3 of 74


Boiler blow down with sample cooler

� For Safety� For Accurate MeasurementFor Accurate Measurement[Result of Lab test from sampling without sample cooler leads to toowithout sample cooler leads to too high TDS, resulting in the excessive blowdown due to loss of flash steamblowdown due to loss of flash steam to atmosphere]



Excessive Blowdown from sampling without sample cooler

Ex : Boiler Pressure 10 barg with boiler TDS = 3500 ppm (mg/l)or TDS / water = 3,500 / 1,000,000 = 0.0035Sample water from 10 barg to ATM will flash by 16%

t f 1 000 000 k ill b 160 000 k f fl h tso water from 1,000,000 kg will be 160,000 kg of flash steamTDS / water new = 3,500 / 840,000 = 0.0042

D i ti [0 0042 0 0035] 100 / 0 0035 20% hi h th th f tDeviation = [0.0042-0.0035]x100 / 0.0035 ~ 20% higher than the fact

So if we calibrate TDS from this lab value then the exact value in theSo if we calibrate TDS from this lab value then the exact value in the boiler is by 2,916 ppm � excessive blowdown � Energy Loss



Heat Recovery from Surface Blowdown



Flash vessel



Flash vessel


GESTRA Flash Vessel Design

� Velocity of evaporation rate is 0 6 0 8 / t id0.6-0.8 m/s to avoid carry over.

� Condensate inlet over a tangential pipe helps reduce

Large diametertangential pipe helps reduce the impact to the vessel.

condensate inlet over a tangential pipea tangential pipe



Heat Recovery Skid










Or conductivity (uS/cm)



BA(E) 46 PN40 Surface blow down valve discharge capacity


(M)PA46 PN40 Bottom blow down valve discharge capacity




261.82 x (781.66-450.51)/2236.86= 38 76 kg/h= 38.76 kg/h= 38.76x 24 x 300 kg/year= 279.07 ton/yeary279,072 x4.18 x (107.434 - 30) kJ/year= 90,328,384 kJ/year

90 328 384 /2236 86 40 38 ton/year


= 90,328,384 /2236.86 = 40.38 ton/year



223.06 x 4.18 x (107.434 - 40) kJ/h= 62,874.41 kJ/h62,874.41/2236.86 kg/h= 28.11 kg/h

28 11 24 300 k /= 28.11 x 24 x 300 kg/year= 202,382.7 kg/year




Sensible heat of blowdown water = 261.82 x 781.66 = 204,654.22 kJ/hat 10 barg (781.66 kJ/kg)

Sensible heat of drain point of = 261.82 x 4.18 x 40 = 43,776.3 kJ/hblowdown water at 40‘Cblowdown water at 40 C(specific heat of water (C) ~ 4.18 kJ/kg)

Energy Recovery = 204 654 22-43 776 3 = 160 877 92 kJ/hEnergy Recovery 204,654.22 43,776.3 160,877.92 kJ/hEquivalent to 0.3 barg steam = 160,877.92 /2,236.86 = 71.92 kg/h(latent heat of steam (r) at 0 3 barg = 2 236 86 kJ/kg)(latent heat of steam (r) at 0.3 barg = 2,236.86 kJ/kg)

Equivalent steam saving per year= 71.92 x 300 x 24 = 517,824 kg/year517 824 985 12(steam cost = 985.12 B/t) = 517.824 x 985.12

~ 510, 118 Baht + Water treatment cost



LevelLevelControlControlMonitorMonitor

Page 42 of 74


Water Level ControlsThe regulations concerning the control of Boilers vary from Country to Country In general however we can say that most Country to Country. In general however we can say that most regulations require the Boiler to be fitted with :-

• Two independent low water alarms

• A device to control the boilerwater level within specified limitswithin specified limits

M t l ti l i th B il Al t b Most regulations also require the Boiler Alarms to betested daily.



Extracted from Transaction Volume 4 Page 43 of 74


Water limiter – Mechanical Float

body

magnetmagnet switch

g

11

rod

measuring chamber

float



Routine test by pressure or magnetic force Water limiter – Mechanical FloatRoutine test by pressure or magnetic force



P bl t l f th i t b tWater limiter – Mechanical Float

Problem not only from the moving part but also the boiler water quality

� Float get struck from scale and dirt� Pitting (not cause boiler explosion)� Pitting (not cause boiler explosion)

Pitures extracted from other Safety Technology Bureau/ DIWENERGY TECHNOLOGY CO., LTD. �0-2721-3860


Former German RegulationWater limiter – Mechanical Float

body

magnetmagnet switch

Former German Regulation

g

Owing to the physical measurement principle and the experience obtained in practice, which i l fl t d i th TÜV d d t fil

11

rodis also reflected in the TÜV damage data files, additional requirements for the operation were issued in the later development of the technical

measuring chamberp

rules; these included a reduction of the maximum permissible boiler-water conductivity f 8 000 t 300 S/ l l t

floatfrom 8,000 to 300 �S/cm, regular replacement of the magnetic switches etc. – measures which were intended to prevent boiler damage p gbut at the same time in-creased the operating costs






extracted from “National Board BULLETIN“ Issue : winter 1999








Test Requirement EN 1295-9 for Mechanical Float in EU

Float Movement : min 250,000 test cyclesElectromechanical switches : min 100,000 cycleOutside float and inside chamber : min 10 mmOutside float and inside chamber : min 10 mmNo float switches for LW in EU



Developement of GESTRA boiler control equipment

19992010

NRG 161999NRG 261981

ER 961978 ER 551977

ER 7719721969

1980ER 83-3First Capacitance

NRG 16 SIL3

ER 77MR 16First self monitoring

1969ER 14

First Capacitance



Measuring Principals

� Conductive: For level detection/Control� Conductive: For level detection/Control� Low level limiters� Multiple tip electrodes� Multiple tip electrodes � Conductivity Control

� C it F d l ti L l C t l� Capacitance: For modulating Level Control� Level control� I t t d Hi h l l Al� Integrated High level Alarm



Pressure temperature range of Conductive Electrode

The conductive probes are available for:

Pressure temperature range of Conductive Electrode

The conductive probes are available for:� PN 6 Tmax: 156°C / 313°F Pmax: 6 bar� PN 10 Tmax: 180°C / 356°F Pmax: 10 bar� PN 40 Tmax: 238°C / 460°F Pmax: 32 bar� PN 63 T : 275°C / 527°F P : 60 bar� PN 63 Tmax: 275 C / 527 F Pmax: 60 bar� PN 160 Tmax: 311°C / 592°F Pmax: 100 bar� PN 320 Tmax:: 400°C /752°F P max 183 barmax:: max



Conductive - Simple low level alarm

Isolator

ß

insulator

Probe tipMeßspitze

Meßgefäß

Probe tip

Measuring chamberMeßgefäßMeasuring chamber



Concept Design of Conductivity Electrode



Possible danger of limiter with ‘‘conventional design“

22

insulator

11

Probe tip

M i h bMeasuring chamber

Short curcuit by means of deposits1

condensation after steam penetration2



Simple low level alarm

Isolator

ß

insulator

Probe tipMeßspitze

Meßgefäß

Probe tip

Measuring chamber

� Electrode rod is covered by PTFE to protect the short circuit

MeßgefäßMeasuring chamber**spacer to lock for multipleElectrode tip



Selection of Controller


Spacer to lock electrode tips



Water level limiter ”special design” self monitoring

fi t i l t

monitoring electrode

first insulator

second insulator

probe tip

Monitoring electrodeinsulatorprobe tip

Probe tip



State of the Art Technology - Self Monitoring Level LimiterMeasuredMeasuredValue

Device Status(Alarm,ConfigurationConfiguration,Watch Dog)



Basic of Self Monitoring : Wheatstone bridge

R1/R2 = R3/RxRST = R of insulation across monitoring electrode

R1/R2 = R3/RxIG => 0

and boiler shell => insulation checkRK = R across monitoring electrode and boiler shell

=> scale checkRP1, RP2 = Fixed R of the design circuit



Failure Dianogsis of Periodic Self-Checking Controller



Boiler Equipment acc. TRD

For boiler operation acc.to TRD 604 (max. 72 hrs without supervision) t lf it i l l l li it i d d f b il ti ttwo self-monitoring low –level limiters are required and for boiler operation to TRD602(max. 2 hrs) only one self-monitoring low-level limiter is necessary

Boiler Equipment acc.to PED, EN 12952 and EN12953 S lf it i i t ith i di lf h ki i i d f b ilSelf-monitoring equipment with periodic-self checking is required for boilers with temperature/pressure rating > 1 bar and > 120’C and a volume > 50 lTwo self monitoring low level for 24 hrs without supervisionTwo self-monitoring low-level for 24 hrs without supervision



Function Safety acc.to PED, EN 12952 and EN12953

Since the international standards IEC 61508 and IEC 61511 for functional safety came into effect there has been an ever-increasing demand for sa e y ca e o e ec e e as bee a e e c eas g de a d oanalysing equipment and process instruments that meet the requirementsaccording to SIL (Safety Integrity Level) classification. The European directivesg ( y g y ) pEN12952 and 12953 demand that a hazard analysis shall be carried out for each limiting device function and appropriate levels of functional safety beg yImplemented.Note 1 states :” Typical Safety Integrity Level (SIL) requirements for boiler protective systems are not less than 2”



Safety Integrity Level (SIL) Overview




Page 55 of 74





Safety Integrity Level (SIL) of GESTRA low water limiter



ON-OFF LEVEL CONTROL APPLICATION

Pump on/off

Pump onPump offPump on

Multiple tip electrodeLow Alarm 2

Multiple tip electrode



Inside the Spector Compact NRGS 16-2



On- Off level control with self monitoring low level alarm



On/Off Level ControlAdvantages

� Simple, suitable for low capacity boiler(<3-5 t/h), condensate and feed tankp , p y ( ),

� Inexpensive for investment

� Good for ‘stand by’ boilers� Good for ‘stand by’ boilers.

Disadvantages

� Intense thermal shock stress in the boiler

� Leads to strongly modulating operation of burnerg y g p

� Integration into a heat recovery concept or exhaust gas cooling using the economizer principle is not possiblep p p

� More wear and tear on the feed pump and control gear and burner

� Variable steam pressure and flow rate� Variable steam pressure and flow rate.

� More boiler water carry over. ENERGY TECHNOLOGY CO., LTD. �0-2721-3860 Page 58 of 74


Comparison: Intermittend / ContinousIntermittend with fixed switch points Continuous with variable switch points

High level -Alarm

Pump Off

High level-Alarm

��

Pump OnSet point

��Low level -Alarm Low level - alarm

�



Capacitance level probe

Measuring pipe20 mA

insulator4-20 mA adjustable for the whole probe length

Measuring chamber4 mA

plug



Principle capacitance measurement



Principle capacitance level measurement

Page 60 of 74


Principle capacitance level measurement

Capacitive Reactance XC



Measurement with Capacitance ProbesLow Voltage AC Supply

Current FlowsInsulated

Probe

Less Current Flows

Rod

Liquid in a Metal Vessel

Probe Deeply ImmersedCurrent flows due to Capacitance

Lower Water LevelCurrent flows due to Capacitance between Probe rod and Water

Less Current Flows

Page 61 of 74


Level Calibration of Capacitance Probe�D

��= Dielectric

�D = Steam

�W

�TL

�D = Steam

W = Water

T = Teflon

L = Air

�

Probe tip cannot be cutD

�

��

Durch den Einfluß des Druckes wird der Luftspalt zwischen Teflonisolation und Meßrohr verdrängt

p

W

��

g

Durch den Einfluß der Temperatur längt sich der Teflonschlauch und wird somit dünner

�

�



Modulating level control-conventional



Pump speed control with compact probe NRGT 26-1

Frequency driven feedwater control

Steam4...20 mA

Steam

Speise-wasserFeed water



Modulating Level ControlAdvantagesAdvantages� Economic Operation (economizer)� Higher steam quality (reduce carry over)� Steady steam pressure and flow rate.� No strongly modulating operation of burner and more efficient

burner operation.� Less thermal stress on the boiler shell.� Less wear and tear on the feed pump and burner.� Capability of adapting to difficult situations regarding the

controlled system e.g. sudden change of steam consuptionDisadvantages� Less suitable for ‘stand by’ operation.Less suitable for stand by operation.



Influence of the boiler capacity on the low level switchpoint

Main steam valve Main steam valveLow level limiter Low level limiter

Steam area Steam area

Combustion tube

Fire tube

Shell boiler without steam production Shell boiler with steam productionp p



Sudden increasing steam consumption in the boiler leads to :� Pressure drop in the boiler

� Extension of steam bubbles� Extension of steam bubbles

� Increasing water level

� Closure of the control valve

� Pressure drop leads to increasing burner output

� Steam bubbles are compressed

� Water level decreases partial below low level� Water level decreases partial below low level

� Boiler is shut down due to low level alarm !

� Remedy ????



Mode of Boiler Operation

� Sudden increase in steam consumption� Boiler performance during feedwater filling without� Boiler performance during feedwater filling without

economizer� Operation at higher level or lower pressure of boiler designOperation at higher level or lower pressure of boiler design.� Three elements control for sudden change of steam

consuptionconsuption



Three element control

TICTICD

NLIC

Boiler

W



Boiler equipment with SPECTORbus


Recommendation for installation 40 mm



Recommendation for installation 40 mm



„Self monitoring“ External Low Level Limiter

Risks with external measuring pots :

• Stop-valve blockingStop valve blocking

• Mud inside level pot

F il i h i l l• Failure in changing level detection

Page 67 of 74


Level probe installed in an external measuring pot with SRL



Level probe installed in an external measuring pot with SRL



� Compact Design and compatible to conventional systems�Easily accessible connection terminals�Compact Design and compatible to conventional systems�Supply voltage 24 VDC, improved EMC control (other voltages with separate power unit)�Switchable sensitivity : 0.5 or 10 μS/cm�Supply via reliable networks possible without additional component (inverters)�Supply via reliable networks possible without additional component (inverters)�Intuitive operating using rotary pushbutton or color touch display�SPECTORmodule Touch with separate control unit and greatly extended

functionality�Now also as modulating controller and three-element control �All limiter systems with SIL3 certification


SPECTORmodul TOUCHContinous level controller

NRR 2 52NRR 2-52



Screen shots of NRR 2-52 operating unit URB 50



Screen shots of NRR 2-52 operating unit URB 50



Condensate Monitoring



Diffuse or stray light in water

90° Streulicht Scattering light

Lichtempfänger15° Streulicht Opto reciver

Lichtsender

LichtempfängerDurchlicht

pOpto reciver

Opto transmitterp

Streuung von Feststoffen, daherHauptanwendungsgebiet in derScattering of solids 90°Trinkwasser-Aufbereitung / -Versorgung

Streuung von Öltropfen, daher Anwendung des15° St li ht f h Öl k

Scattering of oil 15°15° Steulichtverfahrens zur Ölerkennung

g



Functional principle of the ORAutomatische Kompensation von Störgrößen wie:

� Verfärbung� Lampenalterung

Automaticly compansation of Variable disturbancep g

� Verschmutzung der GläserVariable disturbance

VentilUmschaltung

AlarmTV AlarmValve switch over

Istwert3 – 12 V

IstwertX Actual value

SollwertW Setpoint

Lampenspannung12 V Voltage 12 V



Saving from Condensate Return Condition : Condensate 1 t/h, P1 = 5 barg, P2 = 0.3 bargSensible heat of blowdown water = 1,000 x 671 = 671,000 kJ/hat 5 barg (671 kJ/kg)

Feed water temp 30’C = 1,000 x 4.18 x 30 = 125,400 kJ/hFeed water temp 30 C 1,000 x 4.18 x 30 125,400 kJ/h(specific heat of water (C) ~ 4.18 kJ/kg)

Energy Recovery = 671 000-125 400 = 545 600 kJ/hEnergy Recovery 671,000 125,400 545,600 kJ/hEquivalent to 0.3 barg steam = 545,600 /2,236.86 ~ 244 kg/h(latent heat of steam (r) at 0 3 barg = 2 236 86 kJ/kg)(latent heat of steam (r) at 0.3 barg = 2,236.86 kJ/kg)

Equivalent steam saving per year= 244 x 300 x 24 = 1,756,800 kg/year1 756 8 1 000(if steam cost = 1,000 B/t) = 1,756.8 x 1,000

~ 1,756, 800 Baht + Water treatment cost



Example of saving from condensate return



Example of saving from condensate return



Page 74 of 74

Intermittent blowdown valve MPA / PA up to PN250 · GESTRA Steam Systems GESTRA Intermittent...

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Transcript of Intermittent blowdown valve MPA / PA up to PN250 · GESTRA Steam Systems GESTRA Intermittent...