![]() ![]() Effective Sealing & SafetyĮquipment used in the liquefaction, transportation, and storage of cryogenic liquids include pumps, vessels, and valves. These devices are specially designed for cold temperatures. Sealing is extremely important since hazards involved with failure can be life threatening - fire, explosion, frostbite, and asphyxiation. It is also becoming a dominant fuel source in the industrial sector for processing things like chemicals, metal, and paper. It is increasingly leveraged in the generation of electricity as a cleaner and less hazardous alternative to coal and nuclear. LNG is used in fleet vehicles as a cleaner burning alternative to gasoline and diesel. LNG can be re-gasified for use in traditional ways such as heating buildings and powering household appliances- cooktops, water heaters, and clothes dryers. Cryogenic fuels such as oxygen are used in spacecraft rocket applications. Embryos for in vitro fertilization (IVF) are stored in liquid nitrogen.īut one of the largest industries is around liquefied natural gas (LNG). Table 1: Expansion Ratios FluidĬryogenic liquids have a number of useful applications. Nitrogen is sprayed on harvested produce to cool and delay the ripening process. ![]() The table below provides examples of common gases, their boiling points, and liquid-to-gas expansion ratios. Liquefaction also reduces transportation expenses and decreases potential hazards that might arise with fluid in a gaseous state. Converting a gas to a liquid saves an exceptional amount of space. Why Cryogenic Temperatures are UsefulĬryogenic temperatures are particularly useful for the phase transition of gases to liquids. Whenever you make an observation in the laboratory that just doesn't "feel" right, trust your instinct, pause, ensure safety, and more thoughtfully assess the situation before proceeding.In this post, you’ll learn about the design and material considerations crucial to successful sealing of liquids and gases in this extreme temperature range. Carry out the experiment in a fume hood behind appropriate shielding, wear appropriate PPE for the situation, and alert your lab-mates what you are planning to do. Whenever you're going to be sealing something with the potential for evaporation/expansion, a quick Henry's Law calculation should be carried out to ensure that the system won't reach a critical pressure and rupture the container. When using LN2 cooling, never use an experimental set-up that contains air or oxygen. If there is an oxidizable material already in the flask (e.g., solvent and/or other organic material), the liquid oxygen may react rapidly even at the LN2 cold bath temperature. An empty vessel exposed to an oxygen headspace, most typically simply open to air, will condense/liquify the oxygen. Use of LN2 always introduces an added layer of risk because it has a lower boiling point (-196 ☌) than oxygen (-183 ☌). Do not let ammonia gas go into the fume hood as it will oxidize anything in it (including the monitor for air flow). Make sure to have a trap to capture ammonia that did not condense. This is the case for many things, not just ammonia-we are too quick to reach for LN2 for many applications (freeze/pump/thaw degassing, for example). There's no need to use LN2 (-196 ☌) when a dry ice +acetone/IPA bath (-78 ☌) would suffice. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |