Ultrafiltration of Kraft Black Liquor: Phase II, Final report

Technical Report · Tue Sep 01 04:00:00 EDT 1987

OSTI ID:6300630

Hill, M K

The major justification for examining ultrafiltration was to lower the viscosity of the Kraft Black Liquor by recovering it as an ultrafiltration permeate from which the highest MW lignin had been removed. The liquor could then be concentrated to a higher percentage solids before firing into the recovery boiler. Consequent energy savings for the 1000 ton/day pulp mill would be 2.05 x 10 Btu/y for each percentage increase in TDS (total dissolved solids) to the recovery boiler. This Phase II report gives data on viscosity with percentage solids of KBL permeates. Another favorable effect of ultrafiltration on the permeate properties is disproportionate removal of multivalent ions including the major scaling ion CaS . If this high-viscosity high-Ca retentate could be treated to lower its viscosity and to release the Ca in a non-scaling form, this would enhance the possibility that ultrafiltration might be useful in a mill situation. Included in this report are data on the results of treating the retentate fraction. Other justifications for this program included further information in KBL properties: lignin MW in the KBL at high pH; elemental and sugar analyses; and differential properties of lignins in the retentate and the permeate fractions. A preliminary economic analysis of ultrafiltration is contained in this report. These analyses indicate that with flux rates now attainable, ultrafiltration would not be economically justified at this time if the only justification is to lower KBL viscosity. For certain situations where high Ca liquors present a scaling problem, especially in an evaporator-limited mill, the economics are more favorable. There are also unsolved problems relating to the use of the high viscosity retentate.

• Research Organization: Maine Univ., Orono (USA)
• DOE Contract Number: AC02-82CE40606
• OSTI ID: 6300630
• Report Number(s): DOE/CE/40606-T4; ON: DE87013555
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
CARBOHYDRATES
COST BENEFIT ANALYSIS
DISPERSIONS
ENERGY CONSERVATION
FILTRATION
INDUSTRY
LIGNIN
MIXTURES
MOLECULAR WEIGHT
ORGANIC COMPOUNDS
PAPER INDUSTRY
POLYSACCHARIDES
SACCHARIDES
SEPARATION PROCESSES
SLURRIES
SUSPENSIONS
ULTRAFILTRATION
VISCOSITY
WOOD
WOOD PRODUCTS INDUSTRY