ASME PTC 4.3 PDF
ASME PTC Air Heaters. ; Status: Active, Most Current; Document Language: English; Published By: ASME International (ASME). The Code on Definitions and Values (ASME PTC 2) defines the meaning and values of basic technical terms and numerical constants that are. Asme Ptc Air Heaters Bw () – Download as PDF File .pdf), Text File .txt) or read online.
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Each air heater heats both primary and secondaryair for half of the unit in separatesectionswith the flue gas mixed before and after the tir heater. Equation A5 producessix setsof partial differential equations. Errors in measurementsare of two types: Enter your account email address to request a password reset: Of interest is the fact that the uncertainty in the design of a heat exchangerestimatedby Jamesis much larger than ptf uncertainty in the estimateof the performance. The ASME code predicts the temperaturecorrectedto the designvalue while the performancecurvespredict the expectedtemperatureat operating conditions.
Asme Ptc Air Heaters Bw () – Free Download PDF
This paper provides a method for evaluating the remaining two temperaturecorrectionsusing the performance curves. A least squarescorrelation or some other curvy fitting technique can be usedto evaluatethe correlation constants.
The inclusion of crossproducts,i terms, addssignificantly to the number of terms that must be evaluated. In most air heaters,the majority of the air in pct flue gasis leakagefrom the higher pressure, air- side of the air heater.
The parametervalues used for the estimation of the uncertainty of the TCFGOT and the bias and random erroreassociatedwith them are shown below in Table I. If you like to setup a quick demo, let us know at support madcad. To overcomethis, the PTC specifiesthat the measuredflue gas outlet temperaturemust be correctedfor differencesfrom 43 inlet air temperature,design inlet flue gas temperature,design X-ratio, and designflue gasrate.
If these temperaturecorrectionsarenot provided by the equipment manufacturer as algorithms or plotsthey can be estimatedby the procedurepresentedin this paper. Enter your personal account email address to request a password reset: If there were no crossproduct terms, asmee duct traverseof 12 samplepoints in Equation A5 would require 72 terms. There were asmee books found for the applied search filters.
This is achievedby evaluatingEquation 4 for the change in one parameterwhile holding the othersconstant. The bias error associatedwith tbe thermocoupleis the samefor all points. Similarly, the gas density is calculated: Remember me for one month.
Should the manufactureralsoprovide proceduresfor calculating the specified PTC temperaturecorrections,the results can be checkedusing the proposedprocedure. An air heater is shown schematicallyin Figure I. As previously mentioned, many of the crossproduct terms must be included in the bias calculationssince the sameequipment was usedto measurea parameter.
About ASME ASME is a not-for-profit membership organization that enables collaboration, knowledge sharing, career enrichment, and skills development across all engineering disciplines, toward asms goal of helping the global engineering community develop solutions to benefit lives and livelihoods. For a numerical approach, Equation 16 must approximate the surfaceofthe pptc as a linear segmentparallel to the true functional relationship.
In the air heater,energy in the flue gas is recovered by the incoming combustion air. If the denominatorof Equation A5 is set equal to Sum1and the numerator equal to Sum2 to simplify the resulting equations,thesepartial differentials are: This is reflected in quation 10 where the X-ratio is correctedto the design leak of zero before being applied to the calculation of the temperaturecorrection.
For the deviation from the design entering air temperature,rclJM,this is: In the caseof the bias error, the crossproduct telms accountfor essentially all of the error in determining the averagetemperature. The velocity is calculated by: Copyright Compu-tecture, Inc.
The bias and random errors were estimatedby separateerror propagationcalculationsfor standard,multipoint sampling arrays in the inlet asmee outlet ducts of the air heater. All of the other parametersare constants.
Asme Ptc 4.3 Air Heaters Bw (1991)
Repetitive measurementstend to reducethe random error. However, this derivation will be general.
The appendixpresentsa brief discussionof this with a more detailed discussionavailable in the project reports5 As discussed in the Appendix, examination of the derivation of thesesampleerrorssuggeststhat for standard, multipoint traversesof utility-scale equipment,the bias and random errorsshown in Table II for these averagetemperaturesand compositionsare typical.
ASME serves 43. wide-ranging technical community through quality programs in continuing education, training and professional development, codes and standards, research, conferences and publications, government relations and asmr forms of outreach. Since the bias errors are not reducedby taking multiple measurements,the bias errors accountfor most of the uncertainty in the final averagetemperatureas shown in Table A-II.
ASME PTC 4.3
The air heaterson Unit 2 were replacedto improve unit efficiency as part of the aame program. With the crossproducts, this increasesto terms. The determinationof the temperaturecorrectionsfor differences from design X-ratio and design flue gas flow are left to the supplier or purchaserto determine.
In the caseof Equation ;tc, the air leak introduces a significant non-linearity which invalidates this approach. Normally the manufacturer will supply the purchaserwith designperformancecurves or equations,but not with those to calculatethe temperaturecorrectionsspecified by the PTC.
ASME PTC Air Heaters, –
However, using the coal feedrate,from calibrated feeders,and gas compositions as a basecreatesa commonbond betweenthe air and flue gas flows. Since the X-ratio is defined aathe weight times heat capacityratio of the air over that of the flue gas, the X-ratio can be approximatedas the ratio of the temperaturechangesfor the two fluids: Background As part of the I-J. For the details of the estimation of the uncertaintiesof other parameters,refer to the final Milliken project report8 Only the errors and uncertainty for theseother evaluations are presentedhere.
Thus, they apply to any air heater. Founded in by a small group of leading industrialists, ASME has grown through the decades to include more thanmembers in countries.
The bias and random errors are propagatedseparatelyusing Taylor seriesexpansionsfor highly nonlinear equations: Substituting 14 into Equation 11 and then expandingEquation 1 by substituting Equations2,3,11, and 12, along with the air heaterperformance correlations Equations5 and 6resultsin the following revised equation: Instead,performanceindicators such asthe measuredeffectivenessof the air- and gas-sidesand the X-ratio are compareddirectly againstdesign values.
In operating plants, asm is generally impossibleto establishdesign conditions to verify performance.