High pressure liquefied carbon dioxide: a low entropy substance capable of releasing large amounts of hazardous energy

摘要

Carbon dioxide is a ubiquitous gas that under sufficient pressure can be liquefied at room temperature and 860 psi. It is commonly used as a fire extinguisher substance under this pressure. It will eventually also be used in the dry cleaning business. In becoming a liquid through compression much heat is removed as it returns to room temperature. The removal of heat leaves the liquid in a substantially lowered entropy state, which subsequently enables the carbon dioxide to reabsorb heat from the its ambient surroundings. The absorption of heat can be extremely rapid if the gas is allowed to escape quickly from its container. It is this heat that converts to mechanical energy as the jet action of the escaping gas can cause the container to sustain a large velocity and thus wreak considerable havoc, ever more so than an equal volume of compressed nitrogen at 2000 psi.