Patent ID: 8759498

Claim:
A composition, comprising: lignin; and less than about 2000 mg in total per kg of said lignin of elements; wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn; wherein said composition is produced by a process comprising: providing a mixture comprising lignocellulosic biomass and water; heating said mixture to a first temperature of about 130° C. to about 250° C. and maintaining said first temperature for a period of about 0.5 min to about 5 hours, thereby producing a solids fraction and a liquid fraction; and subjecting said solids fraction to a supercritical or near-critical fluid under a pressure of about 40 bar to about 300 bar; wherein said supercritical or near-critical fluid comprises water; wherein said supercritical or near-critical fluid is at a temperature of about 374° C. to about 600° C.; wherein said subjecting step elevates said solids fraction to a second temperature of about 250° C. to about 450° C.; and wherein said solids fraction is maintained at said second temperature for a period of about 0.05 sec to about 10 sec.