Throttling Process & Joule Thomson Effect

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The throttling process is an isenthalpic process where enthalpy remains constant, leading to a relationship between internal energy and pressure. The Joule-Thomson effect describes how a gas cools upon expansion, although hydrogen behaves differently and heats up during expansion, making it hazardous. In the context of a CNG kit, the pressure drop from 300 bar to 4 bar in the pressure regulator involves a throttling process, resulting in a temperature drop. The discussion also raises a question about the Joule-Thomson coefficient for methane, indicating interest in its thermodynamic properties. Understanding these concepts is crucial for applications involving gas expansion and pressure regulation.
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What is the throttling Process?
what is Joule homson Effect?
 
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A throttling process is a process that is isenthalpic. Thus, h_1 = h_2. This means that the following is also true, u_1 + P_1 v_1 = u_2 + P_2 v_2. So if you drop pressure in a throttling value, you increase the internal energy, and vise versa.

The Joule -thomson- effect deals with the fact that as you expand a gas it looses temperature. Note that for hydrogen; however, it gains temperaturee as it expands. This makes hyrdogen particularly dagnerous.
 
Pressure drops in CNG kit Pressure regulator from 300 bar to 4 bar in 1st chamber due to expansion is it throttling process? temperature also drops in it.
 
Yes, that is exactly what it is.

Edit: wait, what do you mean by expansion? Is it going through a nozzle?
 
no it is going throug valve (sloninoid valve) from storage cylinder through high pressure pipe into solinoid valve and then in the 1st stage chamber of pressure regulator.
 
Yes, it is a throttling valve.
 
what is the value of joule-thomson coefficient for methane
 
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