Lab #1b Determination Of Steam Quality - NCSU
Lab #1bDetermination of Steam Quality
Outline Goal of labPhase diagram of waterSaturated steam tableSteam qualityDetermination of steam qualityThermos flaskBoiler– Fire tube, water tube Steam trap– Mechanical, thermostatic, thermodynamic2
Goal of the Lab Determination of steam quality (x) in our pilot plantusing mass and energy balances Familiarization with types of boilers3
Phase Diagram of WaterPressureSaturated liquidWithin the dome,water exists as steam,SubcooledSaturated vapor which is a mixture ofLiq. Vap.liqliquid and vapor.Const. temp. 5 6 Vap.Liq. 2Here, temperature341Superheated steam and pressure areSaturated steamconstant and are1: Sub-cooled liquid2: SaturatedHc HvHv liquidcalled the saturation3: Sat. steam (low qual.)4: Sat. steam (high qual.)temperature and5: Saturated vaporEnthalpy (H) 6: Superheated vapor pressure respectively.** *** *Left of dome: Subcooled liq; Within dome: Saturated steam; Right of dome: Superheated steamAs we move from left to right within the dome, more and more of thewater is in vapor phase. The fraction that is in vapor phase is calledsteam quality (denoted by ‘x’). It varies from 0 to 1 OR 0% to 100%.Latent heat of vap. ( vap) at any temp. or pr. Hv – Hcat that temp. or pr.4
Saturated Steam TableAtmospheric pressureTemperature( C)361.3What is the latent heat of vaporization of water at atmospheric pressure? vap (at atm. Pr.) Hv (at atm Pr.) – Hc (at atm. Pr.) 2676.1 – 419.04 2257.06 kJ/kg 5
Steam Quality (x) The term “Steam” generally refers to saturated steam and notsuperheated steam “Steam” is a mixture of liquid (condensate) and vapor The enthalpy of steam (Hs) is a weighted mean of enthalpy ofcondensate (Hc) and enthalpy of vapor (Hv) Hs x Hv (1 – x) Hc Rearranging,x (Hs – Hc)/(Hv – Hc) Note thatx 0 when Hs Hc Also,x 1 when Hs Hv Higher the steam quality, higher the value of Hs 0 x 1OR0% x 100%Note: Hc & Hv at saturation temperature & pressure are determinedfrom steam tables6
Determination of Steam Qualityms, quality of x; Pressure, P OR Temperature, TSteammc, cp(c), TcCold waterFlaskmh, cp(h), ThHot waterm, cp, T: Mass, specificheat, temperature resp.Subscripts: ‘c’ for cold;‘h’ for hotIntroduce cold water of known mass (mc) and temperature (Tc) in a flaskIntroduce steam into flask till water becomes hot (Th)Determine specific heat of water at Tc and Th from table of properties of waterMass balance: mc ms mhEnergy balance: mc {cp(c)} Tc ms (Hs) mh {cp(h)} ThDetermine Hs from above equationUse interpolation for:Also, Hs (x) Hv (1 – x) Hccp(c), cp(h), Hc, Hvwith Hv and Hc being determined from steam tablesat the absolute (not gauge) steam pressure of P or steam temperature of TThus, x (Hs – Hc)/(Hv – Hc)7
Thermos FlaskConduction and convection heat loss: Decreased by vacuum, stopper,glass, cork, airRadiation heat loss: Decreased by reflective (silvered) glass8
Generation of Steam Water is converted to steam (in a boiler) using abasic source of energy– Fuel oil, natural gas, wood, coal, heating element– One of the above is used to generate hot gases which heatthe metallic surface (usually steel) in contact with waterto generate steam9
Fire Tube Boiler Hot gases are inside tubes surrounded by waterThe heat vaporizes water and converts it to steamAs needed, steam is released from the boilerFire tubes boilers are well suited for applicationswhere there are large fluctuations in demand forsteam10
Fire Tube Boiler11
Water Tube Boiler Hot gases are outside tubes through which waterflows The heat vaporizes water and converts it to steam As needed, steam is released from the boiler Rate of heat transfer is higher in a water tube boiler– This is due to turbulence of water in the tubes Water tube boilers operate at larger capacities andhigher pressures They are more flexible and safer– Safety relates to phase change taking place in small tubesand not in a large vessel12
Water Tube Boiler13
Steam Trap What is a steam trap?– A device that separates the liquid and vapor phases ofsteam Functions of a steam trap– Prevent steam from escaping through it– Allow condensate to pass through it– Discharge air and any other gas through it14
Types of Steam Traps Mechanical– Based on density difference between vapor andcondensate (inverted bucket) Thermostatic– Based on temperature difference between vapor andcondensate Thermodynamic– Based on pressure difference as vapor condenses15
Saturated steam table Steam quality Determination of steam quality Thermos flask Boiler –Fire tube, water tube Steam trap –Mechanical, thermostatic, thermodynamic 2. Goal of the Lab Determination of steam quality (x) in our pilot plant using mass and energy balances
17 Table 3. Compressed Water and Superheated Steam (continued) 0.01 MPa (ts 45.806 C) 0.02 MPa (t s 60.058 C) 0.03 MPa (t s 69.095 C) v ρh s t, C v h s t, C v ρ h s 26 446. 0.037 814 3076.7 9.2827 300 13 220. 0.075 645 3076.5 8.9625 300 8811.0 0.113 49 File Size: 630KBPage Count: 60Explore furtherCalculator: Superheated Steam Table TLV - A Steam .www.tlv.comSuperheated Steam Tables - Gilson Enggilsoneng.comCalculator: Superheated Steam Table TLV - A Steam .www.tlv.comCalculator: Superheated Steam Table TLV - A Steam .www.tlv.comSteam Table Calculator Superheated Steam Region Spirax .www.spiraxsarco.comRecommended to you b
Page 2 June 2015 Large Steam Power Plants Siemens Steam Turbines for coal-fired Steam Power Plants Power output 120 MW to 700 MW Max. steam parameters Main steam / Hot reheat steam 177 bar / 600 ºC / 620 ºC 2,570 psi / 1,110 ºF / 1,150 ºF SST-5000 series for coal-fired Steam Power Plants
2. Use the steam control to select the amount of steam you want ( m low, l medium, h high). 3.2. Squeeze the steam button to produce steam, release it to stop. NOTE: When you first start your steam station and pull the trigger for steam ironing, there will be a delay as your steam station pumps water from the reservoir to prime the system.
Superheated steam. Properties of steam Steam tables To determine various steam properties . Guide C, Section 4, or IOP Guide Total enthalpy, h g h f (sensible) h fg (latent) Extract from superheated steam tables Extract from the saturated steam tables Do you know how to use these steam tables? (Source: www.spiraxsarco.com .
Steam Source All sterilizers are supplied ready to accept a site steam supply of 50 to 80 psi. The sterilizer steam connection is valved and trapped to accept a ½ NPT steam supply. If site steam is not available, please see the steam generator option below. Steam pipe work is constructe
Steam traps that discharge into a steam header should be checked for proper oper-ation. Badly leaking steam traps can over pressure a steam header. Examine turbines. If let down valves are not contributing to the excess steam prob-lem, steam turbines exhausting into that header should be examined. Hand valv
steam nozzle on the hand-held steam cleaner or hose. Firmly press the hose or variable nozzle onto the steam nozzle (7) of the hand-held steam cleaner or hose such that it is fully seated, and release the clips. WARNING: CInspect the seal on the steam nozzle of the hose and handheald steam cleaner before each use (Figure C). If the seal is .
11th August 2020 Please ensure your microphone is muted throughout the presentation The slides today will be presented with the opportunity for the audience to post questions during the presentation using the chat function. Questions submitted through the chat function will be recorded and responses will be provided after the event. Responses will be posted on CCS website page and will be .
