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Overheated steam temperature and pressure compensation was performed in the DCS system

2008-12-10View Original

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I work in instrument design, and I’m currently working on a project related to energy metering. Steam is measured using the ABB vortex flow meter FV4000. Since the steam supplied by the process is not saturated steam but superheated steam, it is necessary to compensate for both its temperature and pressure simultaneously. As far as I know, the FV4000 with an integrated temperature transmitter can only handle saturated steam, converting volumetric flow rate to mass flow rate internally. And superheated steam seems to be able to have its temperature and pressure compensated only within the DCS system. The DCS system for this project is Honeywell’s PKS R201. I’m not very familiar with Honeywell’s systems. Could those of you who are more knowledgeable tell me: does Honeywell’s DCS come equipped with any pre-built modules for compensating the temperature and pressure of superheated steam? The engineering staff in charge of programming said there are no ready-made modules available, and asked us to provide the formulas. However, the density of superheated steam is generally determined by consulting a superheated steam density table. But if we were to incorporate the density table into the DCS, wouldn’t that require too much work? It’s not very practical, is it? The most convenient method should be to perform the calculation directly using a formula. However, it is said that the fitting formula for steam has a relatively large deviation. So I would like to ask those with similar experience: how is temperature and pressure compensation for superheated steam handled in a DCS? There is also an issue regarding ABB vortex flowmeters: when selecting them, we opted for those equipped with an integrated temperature transmitter. However, since compensation is not limited to temperature alone, it is necessary to send this temperature signal to the DCS; whereas flowmeters connected via I/O can only transmit flow signals. I would like to ask whether it is possible to extract the temperature signal separately for use in temperature compensation without using communication methods Is it possible to directly connect the Pt100 signal from the sensor of the split-flow meter to the DCS – by using the operation manual, it was found that the sensor has two signals connected to the converter: one is the flow rate signal and the other is the Pt100 signal The calibration of the flow meter should be carried out under standard conditions, and the instrument coefficient K is also the value at standard conditions. And for steam used at 180°C, should the K value be compensated? Those who have used ABB vortex flowmeters, please provide a compensation formula! Thank you all!
Reply #22008-12-11
Bear it yourself! I hope everyone can help! !
Reply #32008-12-13
Friend, add an integrator (one designed for superheated steam). Feed the flow rate, temperature, and pressure into the integrator, which will then send the data to the DCS system.
Reply #42008-12-14
Oh, I get it now! Thank you all!
Reply #52009-08-12
Calculate it using the formula by yourself~ It’s very simple
Reply #62014-07-26
It is said that the error in temperature and pressure compensation within DCS is relatively large, compared to the method of using an integrator to output the mass flow rate after compensation

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