Phillips Petroleum Company

John E Blaesi

William S Stewart

John D Hottovy

A feedforward control system for a multiple-effect evaporator is provided wherein control is based on maintaining desired values for inferential variables of concentration and boiling point rise for a solution of a solid inorganic substance.

Automatic control of a multiple-effect evaporator

Control of an isomerization process is based on a known relationship between the octane number and temperature of a reaction at equilibrium; and a predetermined relationship between octane number and temperature of the reaction product of a reactor using a specific catalyst. In use, measurements of actual octane number and temperature are compared with the octane number and temperature of a reaction at equilibrium to determine if the reaction is at equilibrium. If the reaction is not at equilibrium, a control signal is developed to restore equilibrium. Thus control of an isomerization process is accomplished so as to substantially maximize the efficiency of the isomerization process both from a production standpoint and from an energy usage standpoint by maintaining the isomerization reaction at desired equilibrium conditions. Also, for a dual reactor system, the differential temperature between the two reactors is manipulated so as to maintain more favorable isomerization conditions in the tail reactor. Energy efficiency is improved by substantially minimizing the amount of heating fluid utilized to preheat the feed to the isomerization process.

Control of an isomerization process

In an aromatic extraction process, the flow rate of aromatics to the extraction column is utilized to control the downstream stripping column so as to maintain a desired purity of the aromatic extract stream withdrawn from the stripping column. Also, the flow rate of solvent to the extraction column is manipulated so as to maintain a desired aromatic concentration in the raffinate stream withdrawn from the extraction column. This control, together with other interactive control functions, results in a control of the aromatic extraction process which substantially maximizes the profitability of the extraction process.

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Bartlesville, OK, United States of America

John E Blaesi