Installing, operating, and maintaining DC motors in a paper mill environment

A nonlinear optimal control approach for the pulping process of paper mills

“…The efficient control of the process's primary (and secondary) consistency also determines the motor's load and the quality properties of the produced paper pulp. The significance of the aforementioned control input variables is as follows [1][2][3][4][5]: u 1 : the chip transfer screw speed. The chip transfer screw for the primary refiner is the main manipulated variable that controls the flow of chips from the preheater at the pretreatment stage to the inlet of the primary refiner.…”

“…The multi-stage mechanical pulping process comprises the following stages [1][2][3][4][5]: (i) wood chip pre-treatment, (ii) wood chip refining, and (iii) pulp refining. In the wood chip pretreatment stage, wood chips are screened to remove over and under-sized particles and next they are heated and steamed at a temperature of about 100°C.…”

“…The significance of the aforementioned state variables and control inputs is as follows [1][2][3][4][5]:…”

“…Another quality indicator is the pulp consistency which stands for the ratio of the mass of dry fibres over the sum of the total mass of dry fibres and of the water suspension. When this ratio is between 20% and 50% the pulp is considered to be of high consistency, while when it ranges between 3% and 5% the pulp is considered to be low consistency [1][2][3][4][5].…”

“…The mechanical pulping process is among the most energy intensive processes in industry [1][2][3][4][5]. Paper is an important commodity, and the demand for paper of various types and quantity grows steadily [6][7][8][9][10].…”