Automatic qualitative trend simulation method for diagnosing faults in industrial processes

•An automatic method of qualitative simulation for industrial processes is proposed.•It requires a minimum set of system equations and data easily obtained in the plant.•It is able to significantly reduce the number of compatible patterns.•An algorithm to obtain the solutions from the qualitative equations is presented.

This work proposes an automatic method of qualitative simulation for industrial processes to predict the steady-state measurement patterns arising from different faults. Due to their characteristics, qualitative simulations tend to generate multiple spurious solutions. The proposed method limits the number of such spurious solutions by automatically generating new qualitative equations from the generic quantitative model (i.e. without the need of knowing the value of its parameters) and using simple qualitative known relations or other readily available information. An algorithm to obtain such solutions from the set of qualitative equations is also presented.