Clemson University

David A Bruce

Lawrence Corlies Murdoch

Mark C Thies

Ronald W Falta

James W Castle

Adam S Klett

Methods for obtaining purified lignin and the lignin that can be obtained by the methods are described. Methods include processing pretreated lignocellulosic biomass feedstock to recover the lignin and provide a lignin composition with a very low level of impurities such as metals and ash. In addition, the lignin recovered from the process can have a narrow molecular weight distribution and, depending upon the specific stages utilized in the process, can have a predetermined molecular weight. The process includes one or more separation stages in which a lignin-containing feedstock is mixed with a solvent solution. The mixture fractionates to form a solvent-rich liquid phase and a lignin-rich liquid phase, the lignin being partitioned across the phases according to the molecular weight of the lignin. Furthermore, the metal salts of the pretreated lignocellulosic biomass feedstock also partition across the phases.

Solvent and recovery process for lignin

Disclosed is a process for manufacturing underground caverns suitable in one embodiment for storage of large volumes of gaseous or liquid materials. The method is an acid dissolution process that can be utilized to form caverns in carbonate rock formations. The caverns can be used to store large quantities of materials near transportation facilities or destination markets. The caverns can be used for storage of materials including fossil fuels, such as natural gas, refined products formed from fossil fuels, or waste materials, such as hazardous waste materials. The caverns can also be utilized for applications involving human access such as recreation or research. The method can also be utilized to form calcium chloride as a by-product of the cavern formation process.

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Central, SC, United States of America

David A Bruce