Natural gas water dew point detection
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For dried natural gas, does its dew point vary under different pressure conditions? For example, if a sample is taken from a dry pipeline and another sample is taken after pressurization, will they be different? In theory it should be the same, but after actual measurement, there is a difference of about ten degrees after conversion to standard conditions; I don’t understand why.
Is no one watching? I’m not sure if it’s appropriate to ask this question in this section.
For natural gas dried with an adsorbent, the actual dew points before and after pressurization are different, but the dew point readings obtained using a dew point meter are the same, as dew point meters generally measure the dew point at atmospheric pressure; in other words, the measurement is also taken at atmospheric pressure even after pressurization. Since it is the dew point at atmospheric pressure (i.e., standard conditions), there is no need to convert it to standard conditions.
Dehydration before pressurization means the water dew point will definitely increase after pressurization! But the water content is the same; therefore, when converted to the dew point at normal pressure, the temperature remains the same
OP, regardless of whether it’s dry natural gas or not, as learned in chemistry classes, the dew point of a mixture changes with variations in temperature, pressure, and composition; even a slight change in the P-T-X data will result in a change in the dew point! ! !
This post was last edited by wshhbx on 2009-6-2 21:56. The dew point measurement varies under different pressures. Simply put, the higher the pressure, the more water molecules can precipitate from the gas. And with more water molecules, more of them will reach the sensor, resulting in a higher dew point. This has been proven through practice. If one is measuring compressed air at atmospheric pressure and with the gas properly vented. You can block the vent to convert it into a pressure measurement; in that case, the dew point will rise immediately. If it doesn’t rise, then the dew point meter is broken. If you want to test natural gas or hydrogen, do it not for your own safety’s sake – it’s too dangerous. These days, many domestic dew point meters are of poor quality and fake; no matter what gas is being measured, the reading shows -60 or -70 degrees. Show it to the customer – look how good these numbers are. See, all the numbers have been adjusted downward. There are also some imported instruments that use relative humidity and temperature to make calculations; from the perspective of measurement traceability, such instruments are not recommended. Clearly, they can only measure values up to -60 or -40, yet they claim to be able to measure down to -80. The data between -60 and -80 is generated through circuit simulation, so it is not accurate and is highly affected by temperature. Moreover, once the reading reaches -60 or -70, the instrument stops functioning. When customers see this, they think it looks better. In reality, dew point measurement should be a dynamic process of equilibrium; generally, high-quality imported sensors are more sensitive and respond to even the slightest amount of moisture. If everyone wants to use it, it is recommended to use Mimsil.