Questions tagged [compressed-gases]
The compressed-gases tag has no usage guidance.
58
questions
1
vote
2
answers
51
views
What is this hole in some gas related threads
What are those holes for? (Those are for CO2.)
Here are a few examples :
- 139
1
vote
1
answer
60
views
Why are double-acting reciproating compressors more efficient than single-acting ones?
On many websites, I read that double-acting reciprocating compressors are more efficient than single-acting compressors.
These sources say it's because they complete two compression cycles on each ...
- 48
0
votes
0
answers
27
views
Can rubber be used as the membrane in a diaphragm compressor with a 1:10 or higher compression ratio?
I've been investing time learning about diaphragm compressors and I can't understand how this particular type of compressor can have a 20:1 compression ratio, and what material could stretch that much ...
- 131
0
votes
0
answers
26
views
How do I purchase cylinders of Hydrogen (H2) gas for person use?
I'm interested in building small model airships, and I would like to purchase a cylinder of H2 gas to fill the envelopes with as is far cheaper and more effective than helium. I've contacted some ...
0
votes
0
answers
27
views
What is the optimum layout for a hydrogen compressor, that would have least wear and tear on the compressor?
I have been investing time in understanding the layout/schematic of a compressor that would be used for compressing hydrogen to high pressure ratings.
It's not clear to me what is the best design - ...
- 131
0
votes
0
answers
6
views
Opposing orientation of multi-stage particulate filter in Nitrogen separation/purification system
I recently purchased an assortment of parts taken out of a Nano Purifications Nitrogen Generator, one of the parts included was a two stage filter for removing particulates from the air stream. The ...
- 1
0
votes
2
answers
93
views
How to calculate the required power to pump out (to vacuum) a container?
Consider I have a cubic container with its volume is 1m cubic as in the simple picture above. It is sealed nicely, it is air proof, no air leaking. I would like to pump out (to vacuum) the container ...
- 219
0
votes
2
answers
161
views
Can a compressor give the same discharge pressure even if suction pressure varies?
The task is to maintain compressor discharge pressure at 200 bars. The inlet pressure varies with time from 200 bars to 10 bars (emptying a compressed air tank and compressing to transfer it to ...
- 9
0
votes
0
answers
16
views
Aspen Plus - Sensitivity Analysis / Case Study - Need Assistance
Can someone please point me in the right direction, I've spent all day on this and have read through the support documentation / user manual.
I want to perform a sensitivity analysis. In this example ...
1
vote
2
answers
82
views
Driving an air cylinder with ignited hydrogen/oxygen gas mixture from fuel cell?
Summary:
I need to build a linear actuator that has a very fast actuating speed but fits in a very small space.
My Question/Idea:
Electric gearmotors, c02, and air pressure, are all ideas that come to ...
- 31
1
vote
1
answer
90
views
How to transfer high pressure hydrogen using flexible pipes?
The task is to transfer hydrogen (high pressure gas > 400 bars) from offshore platform to land. To do so we have to use flexible pipes but for high pressure and high flow rate I'm afraid we can't ...
- 9
1
vote
0
answers
33
views
A 40L compressed air cylinder at 100 bar is emptied in pulses at the rate of 41kg/s. How many such cycles would it take to empty the cylinder? [closed]
I am constructing a blowback gas system where clogged debris needs to be removed with compressed air using compressed air cylinder. 40L compressed air cylinder at 100bar pressure is available as ...
- 11
-1
votes
3
answers
70
views
How to transfer compressed gas GH2 from one tank to another at the same pressure?
The problem is to transfer all the compressed hydrogen from one tank on a ship at 400 bars to fill another tank on earth (also to fill it at 400 bars). What are the common technologies and equipment (...
- 9
0
votes
0
answers
93
views
How to calculate the gas flow rate?
I am using a Venturi burner fed using a lpg cylinder. I need to calculate the gas flow rate?
I am thinking of filling the gas in a balloon/fixed container can take the weight before and after to get ...
- 49
1
vote
1
answer
61
views
If you shut down a gas pipeline for a few months would you fill it with gas at full pressure?
This is of course inspired by the Nordstream gas pipelines in the Baltic Sea. When it was decided that Nordstream 2 would not start operating after construction finished they still filled it with ...
- 113
4
votes
3
answers
539
views
What is the maximum possible compression with fuel injection in a gasoline combustion engine?
Maximum possible compression in a gasoline engine was originally determined by knocking in engines with carburetor. With fuel injection the fuel could be injected after compression and thus eliminate ...
- 151
0
votes
0
answers
25
views
What contributes to the energy cost of multistage compression at high discharge pressures?
I'm getting into hydrogen compression from a theoretical point of view and am looking for a model to describe the energy requirements.
I've gathered, that hydrogen is often compressed with piston ...
- 101
1
vote
1
answer
48
views
Is it feasible to compress cleaned Biogas?
Biogas generated from anaerobic digestion mainly contains around 50-60% $CH_4$, 35-40% $CO_2$, small amount of $N_2$, saturated $H_2O$ and trace of $H_2S$. It's upgraded to automotive fuel grade by ...
- 113
1
vote
2
answers
152
views
Constant Pressure Variable Volume Tanks
Do constant-pressure variable-volume tanks exist in industry? I've read about water-column and membrane-based designs, do either of these exist as OTS components, and where would one get them?
Edit: ...
- 11
0
votes
0
answers
126
views
Calculating gas volume in a gas-liquid system/pressurized vessel
There is water in a tank and the tank is connected to a piece of piping that has a volume of 2.5L.
The headspace above the water is pressurised by using air, to a pressure of 3 bar (a).
What happens ...
- 11
0
votes
3
answers
53
views
Is it possible to remove a split unit's head, and replace it by a false-ceiling head?
Normal split unit:
Ducted split unit:
I have:
Outdoor split unit that compresses gas.
Compressed gas moves down to some room where it connects to some wall-mounted indoor split unit.
The indoor ...
- 117
-1
votes
2
answers
500
views
Energy required to liquify gaseous oxygen?
Does anyone know where I can find some documentation of a real-world liquification process, and the energy costs?
I can calculate the heat that must be removed from O2 gas to get to liquid, but how ...
- 109
0
votes
1
answer
120
views
Recommended books for process engineering? [closed]
I made a career change from machine design to CNG processing. What I’m looking for are some good books/handbooks that cover the following topics. Something similar to Machinery’s Handbook.
Piping, ...
- 53
1
vote
1
answer
60
views
Replace Hydrogen in an air cylinder
Can we use a gas cylinder made of A6061, meant to carry air up to 300 bar, with Hydrogen up to the same pressure? If not, what is the maximum pressure that one can safely use hydrogen with?
- 11
4
votes
2
answers
211
views
Time-rate of change of P and T in a pressurized rigid volume with a hole in it
I am trying to model the time-rate of change of pressure and temperature of a gas being held within a pressurized rigid volume as it escapes: an unsteady, open system with no heat transfer. Most ...
- 49
1
vote
2
answers
102
views
What is the purpose of combustor in a gas turbine
I have read online that a gas turbine converts the chemical energy in the fuel gas to mechanical energy of the turbine blades. The way I see it, because of this hot air one would have to go for heat ...
- 111
-1
votes
1
answer
110
views
Should pressure vessel head be thicker than wall [closed]
I wondering should the head of a rectangular pressure vessel cylinder be thicker than the wall ?
-1
votes
1
answer
370
views
Relation between Inlet and Outlet mass flow rate for a turbocharger?
For the compressor maps for automotive turbochargers, the Corrected mass flow rate (at inlet) is given as abscissa. However, I wish to know the mass flow rate at the outlet. What is the relation in ...
4
votes
4
answers
2k
views
Is it possible to increase the heat output of a gas stove by connecting two gas supply canisters to it at the same time, and is it safe to do so?
Here's a typical outdoor gas stove:
It is fed by a low-pressure gas supply in the form of a camping cartridge or via an LPG cylinder connected to a low-pressure regulator (around 30mbar) like this ...
- 151
1
vote
0
answers
18
views
Skelet Theorie, can anyone help?
I am studying Gas dynamics and came across the lift angle approximation as based on Skelett Theorie (in german). I have done google searches on finding this theory but no luck on any information. Can ...
- 19
1
vote
0
answers
61
views
Can any Air rotameter be used for refrigerant gas by using equation conversion?
Currently, I am trying to find rotameter calibrated for R134A gas flow. However, most companies only sell rotameter or variable area flowmeter for water/Air/Nitrogen flow. Is it possible to use any ...
- 11
4
votes
1
answer
39
views
gas regulator exhaust gas during diaphragm adjustment?
On my air tool compressor or scuba gear you can see or hear a diaphragm regulator sloughing off a tiny amount of gas to the atmosphere when you adjust the regulator down. Does a natural gas regulator ...
- 222
1
vote
1
answer
40
views
Real life example of motor/piston involving an isoterm process?
So I am involved in an introductory course in mathematics for pilots. I have the following problem I would like to give them, as it can be a practical application of integration
However, does there ...
- 111
2
votes
1
answer
105
views
Do pressurised cans still pose a risk to bursting in normal conditions, but after being exposed to heat?
We're planning on shipping some items from the US to Australia as you cannot get them here, that being:
https://www.chewy.com/sentry-stop-that-noise-pheromone-dog/dp/56486
I have been in contact ...
- 23
1
vote
0
answers
68
views
Injecting CO$_2$ into water: how does injection work?
I've been wanting to design my own water carbonation device for a while.
For reference, I've been looking at devices like the Sodastream, which injects pure CO$_2$ into water to dissolve it with up to ...
- 11
0
votes
2
answers
122
views
Ideal gas law, theory vs reality
I am trying to get an idea of the amount of hydrogen that I can store in some pressurized steel tanks underground.
Based on the ideal gas law PV=nRT
I did a simple calculation
pressure = 200bar
...
- 13
0
votes
1
answer
34
views
hydrostatic storage of gasses
This question is a bit general but hopefully someone can point me in the right direction.
If you have a metal container, welded shut that's fitted into a hole that is say 10 meters wide and 30 meters ...
- 13
2
votes
0
answers
18
views
Parts needed for controlling vacuum line pressure with pressurized nitrogen
I'm trying to assemble a simple setup where a line which is typically under vacuum can be pressurized by an external nitrogen supply, with this pressure regulated to less than 1 bar absolute (let's ...
- 21
0
votes
2
answers
6k
views
Calculating mass of gas in container
Given pressure is directly proportional to density, my understanding is that you can use the pressure of gas in a container to calculate the mass of the gas in the container. My reasoning being;
$p=k\...
- 345
1
vote
2
answers
320
views
Cheapest way to measure gas flow (mass)?
I understand that there are quite a few fairly simple and cheap methods to measure the flow of gas in terms of volume, allowing you to get a flow rate in terms of litres per minute for example.
...
- 345
1
vote
1
answer
135
views
Do you adjust gas flow rate (SCCM) to volume of chamber?
If I am carrying out a reaction by flowing 200 SCCM of a gas in a 20mm diameter pipe at 100mm length, if I change the pipe diameter to 10mm:
Do I adjust the mass flow rate of the gases?
If so, how do ...
- 13
2
votes
0
answers
67
views
How to balance flow and pressure in nitrogen purged chambers?
I have an instrument that is technically a humidity controlled chamber. It measures how much moisture is picked up by the sample through a microbalance(Zone 1). Nitrogen gas flows from zone 3 and ...
- 21
0
votes
2
answers
906
views
Is it standard practice to use a pressure relief valve as a pressure regulator?
I'm attempting to understand the difference between a pressure relief valve and a pressure regulating valve. From my research far, I've come to the following conclusion:
Pressure relief valves are ...
- 189
2
votes
2
answers
1k
views
Lpg cylinder to compressed air tank
I am building a small robot having pneumatic system. I am using 12v car tyre inflator as my compressor.But i didn't find any 3ltr to 6ltr standardrd air tank. Can i convert my old 3ltr lpg tank into ...
0
votes
1
answer
2k
views
compare l/min output of CO2 pressure reducer to bar (compressed air)
I have a pressure reducer calibrated for Argon and CO$_2$ output. If I connected it to a gas tank with compressed air, how can I convert the output information "liters of Argon / CO$_2$ per minute" to ...
- 123
2
votes
1
answer
525
views
volume comparison of compressed air and gas duster
I'm currently using 400ml Dust Off 67 gas dusters and want to replace them with compressed air and a blow-out gun.
In order to select the right equipment and get a better understanding I would like ...
- 123
12
votes
1
answer
3k
views
Why was Freon used in spray cans before it was declared a threat to ozone?
I've heard that in the past, spray cans (aerosol cans) contained Freon. I found that the Montreal Protocol made the usage of Freon illegal due to its effect on the ozone layer, but I can't find the ...
- 614
0
votes
0
answers
68
views
Roskam Book equation of dry air density is not clear. I need explanation
Preface:
Roskam in book "Airplane Aerodynamics and Performance" explains (in paragraph "1.1 ATMOSPHERIC FUNDAMENTALS"):
To determne how water vapor affects air density, consider a given volume ...
- 177
2
votes
1
answer
1k
views
Isentropic flow equation derivation
I am trying to derive the isentropic flow equations for a compressible gas by myself and at the end, I have different formulation than the one in the literature. Can you please tell me what am I doing ...
- 614
0
votes
1
answer
734
views
Will helium gas lift more weight in air when it is spread over large volume compared to equal weight heavily compressed small volume?
Is it possible for a weather balloons filled with helium gas to lift the weight of itself and a helium tank(highest psi possible) which can fit the volume of the lifting gas in it?
Assuming a typical ...
- 5