Will high-pressure compression of air cause a Hydrogen EXPLOSION?
Will high-pressure compression of air cause a Hydrogen EXPLOSION?
(OP)
Hi all,
I am an MSChE working as an environmental consultant. I have a client who has designed a 1600-gallon vacuum enclosure in which he can open 30-gallon drums of waste and collect any tritium (isotope of hydrogen) which may be present in the drums. Tritium has many of the same chemical properties as hydrogen, so I'll refer to both hydrogen and tritium as "hydrogen" below.
The drums contain an oily sludge and are estimated to be almost or completely full of the sludge. Thus the mass of tritium in any drum is expected to be very small. There is almost no physical data and no laboratory data on the drum contents because of the radioactivity. It's not something you can just pour into a beaker and play with!
My job is to contact vendors and specify a vacuum pump and a compressor. The client wishes to collect any tritium with the vacuum pump and then compress it to about 2200 psi and store in in welding cylinders for later disposal.
The compressor vendor is concerned about the possibility of explosion. The lower and upper explosive limits of hydrogen in air are 4% and 75% by volume, respectively. I do not expect the concentration of hydrogen to be within the 4% to 75% explosive limits at anytime during the collection and compression process.
The compressor vendor's concern is that at pressure this high (up to 2200 psi), the oxygen and hydrogen are far more prone to react (e.g., ignite or explode) than at atmospheric pressure. Certainly this much pressure will heat up the air and will decrease the volume so that the O2/H2 diatomic molecules will collide more frequently.
Does anyone have experience in compressing air to 2200 psi, especially air that is slightly richer in hydrogen than atmospheric air? Is the vendor's concern justified? Do the normal upper/lower explosive limits apply at high pressure?
Thank you for any guidance you can provide,
Doug Smith
I am an MSChE working as an environmental consultant. I have a client who has designed a 1600-gallon vacuum enclosure in which he can open 30-gallon drums of waste and collect any tritium (isotope of hydrogen) which may be present in the drums. Tritium has many of the same chemical properties as hydrogen, so I'll refer to both hydrogen and tritium as "hydrogen" below.
The drums contain an oily sludge and are estimated to be almost or completely full of the sludge. Thus the mass of tritium in any drum is expected to be very small. There is almost no physical data and no laboratory data on the drum contents because of the radioactivity. It's not something you can just pour into a beaker and play with!
My job is to contact vendors and specify a vacuum pump and a compressor. The client wishes to collect any tritium with the vacuum pump and then compress it to about 2200 psi and store in in welding cylinders for later disposal.
The compressor vendor is concerned about the possibility of explosion. The lower and upper explosive limits of hydrogen in air are 4% and 75% by volume, respectively. I do not expect the concentration of hydrogen to be within the 4% to 75% explosive limits at anytime during the collection and compression process.
The compressor vendor's concern is that at pressure this high (up to 2200 psi), the oxygen and hydrogen are far more prone to react (e.g., ignite or explode) than at atmospheric pressure. Certainly this much pressure will heat up the air and will decrease the volume so that the O2/H2 diatomic molecules will collide more frequently.
Does anyone have experience in compressing air to 2200 psi, especially air that is slightly richer in hydrogen than atmospheric air? Is the vendor's concern justified? Do the normal upper/lower explosive limits apply at high pressure?
Thank you for any guidance you can provide,
Doug Smith





RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
4% to 75% is a wide range. Let's assume that the vacuum enclosure is initially air/oxygen free. When a drum is opened, then could some dissolved oxygen be released from its contents? How can you be sure that the oxygen to hydrogen ratio (or oxygen to VOC ratio) is safe?
I wouldn't be compressing anything unless I was absolutely sure of the composition of the gas to be compressed.
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
There's a little bit on Deuterium too, which is along the lines of your interest.
The bottom line, by my interpretation, is that the potential temperature increase due to compression is more likely to be a problem than the pressure itself but you need to read this stuff to get a feel for it.
The BOM publications are not widely available anymore. I was checking this very issue recently and the GPO told me to go and find my Local Federal Deposit Library and ask them. The copied sections which I have came from the ASME library in NY (at probably 25 cents a page) or perhaps the Inst Mech E library in the UK, I don't remember now.
NASA handle hydrogen under pressure all the time. Perhaps you can get to someone in Cape Canaveral and ask them for information. Start with a switchboard call to "United Space Alliance" and slog your way to someone who knows about this.
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
My thanks to JKEngineer for the Bureau of Mines suggestion and to Flareman for sending me a copy. The BOM document showed that the lower explosive limit for hydrogen was actually higher at 2,200 psi (around 8%) than at atmospheric (4%). That was good news if the 2,200 psi requirement was still in effect.
All the required equipment has been specified and quoted. Thank you to all who replied.
Doug Smith
RE: Will high-pressure compression of air cause a Hydrogen EXPLOSION?
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com