High alpha and high intrinsic viscosity pulp production apparatuses, methods and systems

A method for high intrinsic viscosity pulp production, comprising:

• performing pre-hydrolysis kraft process cooking of hardwood chips in a digester via steam heating to obtain a pre-hydrolysis condition comprising a P factor from 10 to 30;
• adding a white liquor pad to the cooked hardwood chips, wherein the white liquor pad comprises 0% to 5% of a weight of the hardwood chips;
• pre-heating a non-purified cold caustic extraction filtrate having a filtrate concentration of between 40 gEA/l and 60 g EA/l to a filtrate temperature of between 120° C. and 130° C.;
• adding the non-purified cold caustic extraction filtrate to produce alkali impregnated cooked hardwood chips;
• heating the alkali impregnated cooked hardwood chips to a target temperature between 140° C. and 150° C. to reach a target H-factor corresponding to a kappa number between 16 and 18 and produce pulp;
• displacing cooking liquor with a cold wash liquor comprising residual alkali at concentration higher than 2 gEA/l until the pulp is below boiling conditions;
• discharging the pulp from the digester to at least one of an atmospheric discharge tank, atmospheric washing equipment;
• and pressurized washing equipment;
• washing the pulp;
• screening the pulp;
• adding cold fresh alkali, comprising NaOH, white liquor, or both, to the pulp for cold caustic extraction to operate at an extraction temperature of between 30° C. and 35° C. for an extraction time of between 15 and 30 minutes;
• performing counter current washing of the pulp at a washing temperature of between 50° C. and 85° C. to recover the cold caustic extraction filtrate;
• bleaching the pulp in a high selective bleaching sequence comprising a three stage ECF sequence to reach final brightness of between 89% and 91% ISO, wherein the bleaching includes adding at least one of a magnesium salt and a chelating agent;
• dewatering the pulp;
• pressing the pulp;
• drying the pulp;
• and
• forming the pulp into rolls or bales.