System and method of producing micro fibrillated cellulose (MFC)

A method of producing Micro Fibrillated Cellulose (MFC) from a cellulose fiber suspension, comprising the steps of:

• pulping an MFC suspension having a consistency of 0.5-5%;
• following pulping, refining the MFC suspension having the consistency of 0.5-5%;
• following the refining, screening the MFC suspension having the consistency of 0.5-5%;
• following the screening, dewatering the MFC suspension in a continuous pressing device to a consistency of 6-60%, wherein the continuous pressing device is a screw press having a speed, and wherein the continuous pressing device forms a source of filtrate, such that a filtrate is produced therefrom;
• following dewatering, measuring the MFC suspension consistency and measuring a fines content of the filtrate;
• and
• controlling the dewatering of the MFC suspension to a consistency of 6-60% by controlling the dewatering of the MFC suspension in the screw press by adjusting the screw press speed, and by controlling return of at least a part of the filtrate back to the pulping step, the refining step, or the screening step.