Fractionator pressure control system

Claim 1

An apparatus, as set forth in claim 1, wherein the condenser has cooling coils therein, the signal delivered by the controlling means varies directly with the pressure within the column the signal delivered by the liquid level controller varies directly with the height of the liquid level, the first regulating valve is normally open, and the second regulating valve is normally closed.

Claim 4

An apparatus for controlling the pressure within a fractionation column, comprising: a fractionation column having a chamber, sidewalls, and an upper end; a condenser having a chamber, cooling coils within the chamber, and upper and lower portions are connected at the upper portion to and in communication with the upper end of the fractionation column for the removal of liquid from a vapor stream discharging from the column and into the condenser; a pressure transmitter positioned within the vapor stream discharging from the column adapted to measure the pressure within said vapor stream and deliver a signal responsive and directly proportional to said pressure; a pressure controller connected to the pressure transmitter adapted to receive the signal from the pressure controller and deliver a fluid signal responsive and directly related to said received signal; an accumulator having upper and lower portions, an end, and a chamber and being positioned at a higher elevation than the condenser; a liquid conduit having first and second ends attached at the first end to and in communication with the lower portion of the condenser and at the second end to and in communication with the lower portion of the accumulator for the passage of liquid therebetween and the control of pressure within the condenser and the column; a liquid level controller connected to the liquid conduit at a lower elevation than the condenser adapted to measure the height of a liquid level and deliver a fluid signal and directly related to the height of said liquid level; a first gas conduit having first and second ends attached at the first end to and in communication with the upper portion of the condenser spaced from the inlet of the vapor stream and at the second end to and in communication with the upper portion of the accumulator for the flow of gas from the condenser to the accumulator; a second gas conduit attached to and in communication with the accumulator spaced from the inlet of the gas stream from the condenser for the passage of gas from the accumulator; means attached to the pressure controller and the liquid level controller adapted to receive the fluid signals from the pressure controller and the liquid level controller, measure said signals, select the lowest of the signals received, and deliver a fluid signal responsive and directly proportional to said lowest received signal; a first regulating valve which is normally open positioned within the first gas conduit, connected to the selector means adapted to receive the fluid signal from the selector, restricting the passage of gas therethrough in response to a received fluid signal greater than 3 p.s.i.g., progressive; restricting the passage of gas therethrough in direct proportion to an increase of the received fluid signal, and fully restricting the passage of gas in response to a received fluid signal having a pressure in the range of 9 P.s.i.g. or greater for controlling the flow rate of the gas flowing from the column, the condenser to the accumulator, and controlling the pressure within the column; a second regulating valve which is normally closed positioned within the second gas conduit, connected to the pressure controller adapted to receive the fluid signal from the pressure controller, permitting the passage of gas therethrough in response to a received fluid signal greater than preset pressure, permitting a progressively greater passage of gas therethrough in direct proportion to the increase of the received fluid signal for controlling the flow rate of the gas flowing from the accumulator, condenser, and the column and controlling the pressure within the column; reflux conduit attached to and in communication with the lower portion of the accumulator and a sidewall of the column for the flow of liquid for reflux from the accumulator into the column; means within the reflux conduit for controlling the flow rate of liquid from the accumulator to the column and controlling the temperature and pressure within the column; product conduit attached to and in communication with lower portion of the accumulator for the removal of liquid from the accumulator and the system; a liquid level controller attached to and in communication with the accumulator adapted to measure the liquid level within the accumulator and deliver a signal responsive to the height of the liquid level; and control means attached to the accumulator liquid level controller and the product conduit adapted to receive the signal from said liquid level controller and regulate the flow of liquid from the accumulator and the system for controlling the pressure within the accumulator, the condenser, and the column.

Claim 5

A method for controlling the pressure within a fractionation column, comprising; passing a vapor stream from the fractionation column to a condenser; monitoring the pressure of the vapor stream; extracting liquid from the vapor stream; passing the extracted liquid between the condenser and an accumulator for regulating the rate of condensing and maintaining the pressure within the column; monitoring the liquid level height of the extracted liquid; discharging gas from the condenser, through control means, and into the accumulator; regulating the flow rate of gas from the condenser in response to the pressure of the vapor stream and the liquid level height for maintaining the pressure within the column; and intermittently discharging gas from the accumulator and through a regulating valve in response to the pressure of the vapor stream for maintaining the pressure within the column.