Title: Controlling the temperature of a depropanizer tower by chromatographic analysis of feed and bottoms

• Summary
• Claims
• Description
• View all

Abstract: The reboiler temperature of a depropanizer tower is controlled as the function of the propane content of the feed to the depropanizer tower and of the gasoline provided by the tower in accordance with a control signal. The Reid Vapor Pressure of crude oil feeding a flash tower is determined from the propane content of the depropanizer feed while the Reid Vapor Pressure of the gasoline is determined from the gasoline propane content. A control unit includes a network which determines a change in the Reid Vapor Pressure as the quality of the feed crude oil to the flash tower changes. When the change in the Reid Vapor Pressure exceeds a predetermined limit, the network provides a feed forward signal corresponding to a desired temperature associated with the new Reid Vapor pressure. The feed forward desired temperature signal is determined in accordance with the equations hereinafter disclosed. The feed forward desired temperature signal is supplied to a set point signal circuit which implements the feed forward desired temperature signal, after the elapse of a first predetermined time interval to account for the delay time for the change of feed crude oil, to affect the quality of the product from the depropanizer tower. A feedback desired temperature signal is developed from the equations. The set point signal circuit provides the feedback desired temperature signal as the control signal whenever it is not providing the feed forward desired temperature signal as the control signal.


Do you think this is a good invention? Vote now: