Abstract A method of recovering by distillation the separate components of a hydrocarbon gas mixture comprising ethylene, ethane, propylene and propane which comprises separating the ethylene as an overhead from an ethane, propylene and propane bottom in a first distillation tower at from about 500 to about 650 psia, separating ethane as an overhead from a propylene and propane bottom in a second distillation tower at from about 390 to about 520 psia, and separating propylene as an overhead from a propane bottom in a third distillation tower at from about 100 to about 170 psia is disclosed. A method of separating ethylene and ethane from propylene and propane in a first distillation tower at from about 400 to about 600 psia, separating the overhead product from the first tower in a second tower at from about 600 to about 700 psia to produce ethylene and ethane products, and separating a propylene/propane mixture in a third tower at from about 100 to about 170 psia is disclosed. The heat for operating the propylene/propane splitter is derived from the cooling water of a heat exchange system or from hot quench tower oil.
Method of optimizing the expense of the recovery of C 2 /C 3 hydrocarbons from a fluid mixture consisting essentially of ethane, ethylene propane and propylene through fractional distillation comprising: (a) operating a system of distillation towers in a distillation system in which each tower receives a single feed and produces two effluents and wherein certain of the towers has a reboiler wherein the pressure of each tower is within ±15 psia of the pressure, calculated from the formulae: ##EQU2## and wherein: P*=the pressure of each tower in psia T FB =tower feed mixture bubble point temperature (°R) evaluated at 485 psia T.sub.φB =tower overhead product mixture bubble point temperature (°R) evaluated at 485 psia T BD =tower bottom product mixture dew point temperature (°R) evaluated at 485 psia (b) circulating cooling water which has been heated during a heat exchange cooling operation by heat from one of said towers to a temperature of from 80° F. to 130° F., to said reboiler and back to said heat exchanger; (c) feeding at least a portion of said fluid mixture to the internals of the other of said towers; (d) discharging said recovering the effluent distillate product from the top of said internals; and (e) discharging the effluent bottom product from the bottom of said internals.
Claim 2
Dependent Claim
215 words
Method of optimizing the expense of the recovery of C 2 /C 3 hydrocarbons from a fluid mixture consisting essentially of ethane, ethylene propane and propylene through fractional distillation comprising: (a) operating a system of distillation towers in a distillation system in which each tower receives a single feed and produces two effluents and wherein certain of the towers has a reboiler wherein the pressure of each tower is within ±15 psia of the pressure, calculated from the formulae: ##EQU2## and wherein: P*=the pressure of each tower in psia T FB =tower feed mixture bubble point temperature (°R) evaluated at 485 psia T.sub.φB =tower overhead product mixture bubble point temperature (°R) evaluated at 485 psia T BD =tower bottom product mixture dew point temperature (°R) evaluated at 485 psia (b) circulating cooling water which has been heated during a heat exchange cooling operation by heat from one of said towers to a temperature of from 80° F. to 130° F., to said reboiler and back to said heat exchanger; (c) feeding at least a portion of said fluid mixture to the internals of the other of said towers; (d) discharging said recovering the effluent distillate product from the top of said internals; and (e) discharging the effluent bottom product from the bottom of said internals.
Claim 3
Dependent Claim
44 words
The method defined in claim 1 wherein said cooling water passing through said reboiler has a temperature drop of in excess of 15° F. in said reboiler and wherein the pressure of said fluid in said internals is between 100 psia and 170 psia.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said distillate product is essentially polypropylene and said bottom product is essentially propane.