A question about standard metric cube

In summary, the conversation discusses difficulties in sizing a compressor for natural gas, with a focus on volumetric flow rate, power requirements, and assumptions about the gas being an ideal gas. The speaker also raises questions about the specific heat capacities of natural gas and how to calculate them.
  • #1
exergetic
12
0
Hi everybody,
I'm having difficulties sizing a compressor for natural gas.
First,my assumption is to take natural gas as mixture of ideal gases.The compression must be between 9 and 32 bar and it starts at 45 °C.
I know that volumetric flow rate must be 85000 Sm3 per day ,where I assume 15°C and 1 bar as Standard Conditions.
Now how do I think about volumetric flow rate considering conditions of the fluid inside the compressor?
Do I need to change unit of measure of the volumetric flow rate from (Sm3 per day) to (m3 per day) using ideal gas' law?
Because I must find the power required by comrpessor.

Thanks in advance.If I haven't been clear about something tell me.
 
Engineering news on Phys.org
  • #2
Since the gas is being compressed, the volume entering is going to be larger than the volume exiting. Think about it in terms of mass flow rate instead of volumetric flow rate. The same amount of mass has to leave the compressor as came into it.

Also, you shouldn't just assume something is an ideal gas.
 
  • #3
Right,it was just what I was thinking about.My assumption of natural gas as ideal gas was just for approximate its thermophysical proprieties knowing composition of this natural gas.
About this I have also another question:in evaluating power of compression I also need to find the specific work of compression but I should know first the specific heat capacities Cp and Cv (and so them ratio k).
Would it be correct to evaluate Cp and Cv of natural gas as average of the heat capacities of all the component gases weighted on molar fraction?
For example,the mean temperature and pressure of compression are 70°C and 16 bar and natural gas is composed in:75% CH4,15% H2S,10% CO2(in volumes,so in moles).
Is it correct to write:

Cpnatural gas(70°C,16 bar)=CpCH4(70°C,16 bar)*0.75+CpH2S(70°C,16 bar)*0.15+CpCO2(70°C,16 bar)*0.10

and in same way for Cv?
 

1. What is a standard metric cube and how is it used?

A standard metric cube is a cube-shaped object that is used to measure volume and mass in the metric system. It is typically made of plastic or metal and has markings on its sides to indicate different units of measurement.

2. What are the dimensions of a standard metric cube?

A standard metric cube typically has sides that are 10 centimeters in length, making it a 10cm x 10cm x 10cm cube. However, there are also other sizes available, such as a 1cm x 1cm x 1cm cube for more precise measurements.

3. How is a standard metric cube different from a regular cube?

A standard metric cube has specific units of measurement marked on its sides, such as milliliters (ml) for volume and grams (g) for mass. A regular cube does not have these markings and is not used for scientific measurements.

4. Can a standard metric cube be used for non-metric measurements?

No, a standard metric cube is designed specifically for use in the metric system. It would not be accurate to use it for non-metric measurements, such as inches or pounds.

5. Is a standard metric cube necessary for scientific experiments?

It depends on the experiment. If the experiment requires precise measurements of volume or mass, then a standard metric cube would be necessary. However, for more general measurements, other tools may also be used.

Similar threads

  • Materials and Chemical Engineering
Replies
1
Views
341
  • Mechanical Engineering
Replies
3
Views
1K
Replies
2
Views
1K
  • Materials and Chemical Engineering
Replies
2
Views
230
  • Mechanical Engineering
Replies
8
Views
2K
Replies
1
Views
2K
  • Mechanical Engineering
Replies
6
Views
2K
  • Mechanical Engineering
Replies
3
Views
896
  • Mechanical Engineering
Replies
1
Views
1K
  • Mechanical Engineering
Replies
3
Views
11K
Back
Top