Vapor dilution, safe

Safe dilution requirements can be given for the gas phase in a flammability diagram or equation (270,273). Alternatively, safe vapor dilution can be given in terms of the Hquid storage conditions where allowance can be made for solubility of the inert gas in Hquid ethylene oxide (273). 

In the context of dilute solutions, suspensions, or vapors, we can safely regard the historically earliest idealizations of inverse-sixth-power interactions. These are for the conditions that hold in a van der Waals gas. The medium is vacuum the a s and /i s of individual particles already introduced are now those of atoms or small molecules. The vapor is so dilute that its dielectric response is that of the vacuum plus very small contributions proportional to the number density of particles. 

Ventilation by diluting the vapors until they are no longer flammable is one of the most effective ways to prevent the formation of flammable gaseous mixtures. Use appropriate and safe exhaust whenever appreciable quantities of flammable substances are transferred from one container to another, allowed to stand in open containers, heated in open containers, or handled in any other way. In using dilution techniques, make certain that equipment (e.g., fans) used to pro... 

Diluting the general room atmosphere with outdoor air fast enough to keep the concentration of toxic vapor in the room air within safe limits. It may also be known as General Ventilation or Dilution Ventilation. 

NCI3 is much less volatile than chlorine, and so it tends to accumulate in suction chiller bottoms (Section 9.1.6.4A) and in chlorine vaporizers (Section 9.1.8.7) or other vessels from which chlorine is withdrawn as vapor. One method for its removal as a waste from suction chillers has been the dilution of the bottoms with a chlorinated organic. The standard choice for this duty has been carbon tetrachloride. With the use of this solvent restricted under the Montreal protocol, other materials have been suggested as replacements. Chloroform is one possibility, but it is important to note that it (b.p. 61 °C) is more volatile than nitrogen trichloride. Section 17.4.2 outlines problems that can arise with replacement solvents. Section 9.1.11.2E discusses alternative proeesses for the safe destruction of NCI3. 

Butadiene must be kept inhibited in storage to prevent polymerization and the formation of spontaneously flammable peroxides. The inhibitor content of 1,3-butadiene stored for any appreciable period should be regularly measured and maintained at safe levels. Ignition within a storage tank can be prevented by diluting the vapor phase with a sufficient proportion of inert gas. Because of its high volatility. 

Most ovens found in smaller operations are batch models. In one respect, batch ovens are more hazardous than continuous ovens because there will be a peak in the rate of evolution of volatile material. In a continuous process, there is a nearly constant, substantially lower rate of evolution. Much lower rates of ventilation may suffice for dilution of this vapor. In a batch process without complex control or close monitoring, the ventilation rate during much of the cycle will usually be much higher than ideally required. This is wasteful of ventilating gas and thermal energy, and it makes the task of safe removal and recovery of solvent vapors more difficult. 

---