1. A method for operating parallel boilers of an industrial system with advanced process control, the method comprising: developing a model for advanced process control, the model comprising: a model identification phase; and a model combination phase; and wherein: the model identification phase comprises determining models of each parallel unit of a system by performing an identification experiment of each unit of the parallel boilers where each unit is individually enabled while the other boilers are disabled and a model of a remaining system which has no boilers; and the model combination phase comprises a model of a whole system incorporating the models of the parallel boilers and the model of the remaining system; programming the model into an embedded microcontroller; and operating the parallel boilers with the microcontroller in accordance with the model for advanced process control.