Vacuum distillation separates volatile compounds from a liquid mixture by reducing pressure, inducing evaporation, and capturing and condensing the vapor. It is used in petroleum refining and can separate hundreds of hydrocarbons. It is suitable for high boiling point compounds and those dissolved in water. The apparatus can be simple or complex, from laboratory setups to large oil refinery towers.
Vacuum distillation is a process by which volatile compounds are separated from a liquid mixture by exploiting the tendency of such compounds to evaporate from the mixture at a faster rate at lower atmospheric pressures, often without increasing the temperature. By enclosing a mixture in a distillation tank and reducing the pressure, volatile compounds are induced to evaporate from the mixture. The vapor is then captured and condensed back into a liquid. Vacuum distillation can be done on a small scale in a laboratory or on an industrial scale such as is done in petroleum refineries.
Any compound dissolved in a liquid will have a vapor pressure, which is usually expressed as a fraction of a standard atmosphere of pressure, at a specific temperature. It is the pressure at which a particular compound evaporates easily from a liquid solution. Vacuum distillation uses this property to separate individual compounds from mixtures, particularly in the refining of petroleum products. The liquid to be separated is placed in an airtight container with a pressure regulation system. Using known vapor pressures of specific elements of the mixture, the pressure is reduced, and sometimes the temperature is increased, until the desired compound begins to evaporate or boil away from the mixture.
After the desired compound has been converted to vapor, it is collected, cooled, and returned to standard atmospheric pressure to condense. It can also be pressurized to higher than standard atmospheric pressure if it is normally a gas, such as fuels such as propane, that convert it to a liquid. By subjecting a mixture such as crude oil to a variety of temperatures and pressures, many different components of the mixture can be separated and refined in this way. Crude oil can contain hundreds of hydrocarbons, and in many cases, vacuum distillation is the only way to easily and efficiently separate them from each other.
Compounds that have a high boiling point or whose vapors are heavier than air at a standard pressure atmosphere are particularly suitable for separation by vacuum distillation, especially when dissolved in water or a mixture containing water. Vacuum distillation also allows compounds to be distilled at lower temperatures than would otherwise be possible. This is useful for compounds that are altered or broken down by heating.
Vacuum distillation apparatus can be relatively simple, such as those sometimes used in laboratories, or extremely complex, such as large oil refinery towers. A vacuum distillation tower in an oil refinery can be several stories tall and may be capable of separating dozens of hydrocarbon compounds. A small workshop can be very simple and take up no more space than a table.
Protect your devices with Threat Protection by NordVPN
