Chain of Custody Yield Factor Reconciliation across Multi-Site Kraft Paper Mill Networks
Multi-site kraft paper networks reconcile physical process yield losses against certified volume balances through standardized mill conversion factors.
Liquor Solids
Chemical Concentration
Kraft pulping liquor circuits evaporate excess water from weak black liquor to yield a high-density fuel stream for the chemical recovery furnace. Liquor solids defines the percentage mass of dissolved inorganic pulping chemicals and organic lignin fragments contained within kraft black liquor. Process sensors measure this value continuously to verify that concentrated liquor exceeds minimum combustible concentration limits prior to firing.
Precise concentration measurement prevents dangerous steam explosion risks inside the recovery boiler hearth.
Evaporation Process
Multiple-effect evaporator trains extract water from weak black liquor, raising dissolved solids concentration from fifteen percent to over sixty-five percent before combustion. High-efficiency concentrators further elevate this figure above seventy-five percent solids, which increases thermal efficiency and improves smelt bed formation in the furnace bottom. Heavy-duty transfer pumps and steam heating lines maintain fluid flow at elevated solids levels to prevent crystallization in transport piping.
Residual alkali content alters liquor viscosity, directly influencing atomization nozzle performance inside the recovery furnace. Proper solids management ensures efficient green liquor generation and high sodium recovery rates.
Thermal Efficiency
Higher dissolved mass concentrations raise the heating value of black liquor and maximize high-pressure steam generation per ton of virgin pulp produced. Liquor solids monitoring provides the primary operational input for controlling recovery furnace combustion stability and emissions control systems. Precise liquor concentration control safeguards mill energy self-sufficiency and process safety.