Liquid Nitrogen
Liquid nitrogen has also been used as a method for cooling concrete for over twenty years. Liquid nitrogen (LN) is an inert cryogenic fluid with a temperature of − 196 °C [− 320 °F]. LN is injected directly into the batch water storage tank, aggregate, or mixer via lances to lower the temperature of the concrete as much as practical without freezing. LN can be stored at the batch plant or on the project site and if used on the project site itself, then repeated cooling of the concrete and greater control of the concrete temperature is possible. can be set up at a project or plant within a few days and can supplement other cooling methods to achieve a reduction in concrete temperature when necessary (Beaver 2004).
Cryopanelling
Liquid nitrogen cryopanels provide very large pumping speeds for condensable gases, particularly H2O and heavier hydrocarbons, and also, though less effectively, for CO2.[66] Provision of extensive cryopanelling surrounding the deposition region is an essential secondary pump for achieving high quality with some materials,[1]–[7]
Liquid Nitrogen Facts
Liquid nitrogen is Diatomic nitrogen, N2. For this reason, it’s often called LN2.
- Liquid nitrogen is colorless, odorless, flavorless, and non-toxi.
- Liquid nitrogen looks much like boiling water.
- Liquid nitrogen has a low viscosity. In other words, it readily flows.
- Polish physicists Zygmunt Wróblewski and Karol Olszewski were the first to liquefy nitrogen on April 15, 1883.
- Liquid nitrogen is produced by fractional distillation of liquid air.
Liquid Nitrogen Uses
Liquid nitrogen use in many of method
- Science projects, such as demonstrating the Leidenfrost effect, making liquid nitrogen ice cream, making fog, and flash-freezing flowers
- Freezing food for storage and transportation
- Protecting samples from oxygen exposure
- As a source of dry nitrogen gas
- Branding livestock
- Molecular gastronomy
- Cooling materials to make them easier to fracture or machine
- Preserving biological samples
- Cooling superconductors, vacuum pumps, and other equipment
- Cryotherapy, such as wart removal
- Quick-freezing water in pipes for plumbing
- Fire suppression
- Liquid nitrogen use to preservation many things
Safety
Don’t enclose liquid nitrogen in sealed containers. Wear appropriate clothing and protective gear. Wear long pants and either a lab coat or shirt with long sleeves, insulating gloves, eye protection, and shoes with covered toes. Only work with liquid nitrogen in a well-ventilated area and watch for signs of hypoxia. Asphyxiation causes rapid breathing, fatigue, nausea, faulty judgement, and vomiting. These symptoms can proceed to unconsciousness and death. Liquid nitrogen is a common and useful cryogenic gas, but its storage and use requires caution.
Liquid Nitrogen Disadvantages
Prudent Safety Practices
- Liquid nitrogen should be handled in well-ventilated areas.
- Handle the liquid slowly to minimize boiling and splashing. Use tongs to withdraw objects immersed in a cryogenic liquid – Boiling and splashing always occur when charging or filling a warm container with cryogenic liquid or when inserting objects into these liquids.
- Do not transport liquid nitrogen in wide-mouthed glass Dewars or Dewars not protected with safety tape.
- Use only approved containers. Impact resistant containers that can withstand the extremely low temperatures should be used. Materials such as carbon steel, plastic and rubber become brittle at these temperatures.
