Separators Vapor-Hydrocarbon-Water

Further study about hydrocarbons/water separation was made by Yang et while using 4,4-bis(chloromethyl)biphenyl incorporated with triphenylamine. By changing the monomer ratio, a series of hypercrosslinked polymers were obtained with high surface areas and a predominantly microporous structure. With apparent BET surface areas of 1362 m g for PBP-N-25 and 1338 m g for PBP-N-50, the benzene/water vapor selectivity was as high as 53.5 and 63.6, respectively. Moreover, a monolithic polymer (M-PBP-N-25) was prepared with an apparent BET surface area of 551 m g. Owing to its hydrophobic nature and low density, the monolith showed the potential for applications in oil spill cleanup operations. 

Unstabilized gasoline and light gases pass up through the main column and leave as vapor. The overhead vapor is cooled and partially condensed in the fractionator overhead condensers. The stream flows to an overhead receiver, typically operating at <15 psig (<1 bar). Hydrocarbon vapor, hydrocarbon liquid, and water are separated in the drum. 

The toxicity and volume of some deoiled and dewatered sludge can be reduced further through thermal treatment. Thermal sludge treatment units use heat to vaporize the water and volatile components in the feed and leave behind a dry solid residne. The vapors are condensed for separation into hydrocarbon and water components. Noncondensable vapors are either flared or sent to the refinery amine nnit for treatment and nse as refinery fnel gas. 

One process that was developed but not commercialized was the TOSCOAL process, in which crushed coal is fed to a horizontal rotating kiln. There it is heated by hot ceramic balls to between 425 and 540°C. The hydrocarbons, water vapor, and gases are drawn off, and the char is separated from the ceramic balls in a revolving drum with holes in it. The ceramic balls are reheated in a separate furnace by burning some of the product gas. 

Many hydrocarbon mixtures contain a small amount of water. In the processing of such mixtures, three phases are frequently encountered a vapor phase (j = i>), a hydrocarbon liquid phase (j = h) and a water phase (J = w). Consider the case of flash separation of such a hydrocarbon-water mixture. Define... 

Note I—Some gaseous fuels contain vapors of hydntcarbons or other components that easily condense into liquid and sometimes interfere with or mask the water dew point. When this occurs, it is sometimes very helpful to supplement the apparatus in Fig. 1 with an optical attachment that uniformly illuminates the dew-point mirror and also magnifies the condensate on the mirror. With this attachment it is possible, in some cases, to observe separate condensation points of water vapor, hydrocarbons, and glycolamines as well as ice points. However, if the dew point of the condensable hydrocarbons is higher than the water vapor dew point, when such hydrocarbons are present in large amounts, they may flood the mirror and obscure or wash off the water dew point. Best results in distinguishing multiple component dew points are obtained when they are not too closely spaced. 

Often gravity separation in three-phase separators is not adequate to separate the water from the crude oil. A common method for separating the emulsion is to heat the liquid stream. While this improves the oil-water separation process, it also stabilizes the crude by vaporizing the light hydrocarbons. Quite often this results in higher than desired losses or in crude that has a vapor pressure lower than atmospheric at atmospheric temperatures. 

A third important area for gas separation is the removal of water vapor from air or from hydrocarbons. This separation is easily accomplished using adsorption, but the adsorbent beds require periodic regeneration. Membranes, which do not require this regeneration, show selectivities over air and hydrocarbons of thousand to one. Hydrocarbon losses, which are significant now, should improve as the membranes evolve. 

Sprays. Aerosol spray emulsions are of the water-in-oil type. The preferred propellant is a hydrocarbon or mixed hydrocarbon—hydrofluorocarbon. About 25 to 30% propellent, miscible with the oil, remains in the external phase of the emulsion. When this system is dispensed, the propellant vaporizes, leaving behind droplets of the w/o emulsion (Fig. 2b). A vapor tap valve, which tends to produce finely dispersed particles, is employed. Because the propellant and the product concentrate tend to separate on standing, products formulated using this system, such as pesticides and room deodorants, must be shaken before use. 

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