Multivariable control system for regulating process conditions and process optimizing

摘要

A system for regulating and optimizing process conditions, such as octane number, aniline point or density of reformed hydrocarbons, by manipulating various process variables in order to control the process, both in accordance with a regulatory effect, namely, such as to cause the process to achieve and maintain the desired setpoint and setpoints for the process condition or conditions, and in accordance with an optimizing effect, namely, such as to cause the process to achieve some predetermined state defined as optimum. The effects are not necessarily consistent, but relative weights are assigned to the two effects such that the regulating effect is paramount until the process condition or conditions are substantially at setpoint or setpoints, at which time the regulating effect is minimum, thus allowing the optimizing effect to influence the process. In particular, furnace outlet temperatures are directly controlled, using set points which are a joint function of outlet temperatures, octane and skin temperatures. Skin temperatures are used to limit the process, and outlet temperatures are used in the optimization.