High Shear Method to Separate Fractions in Woody Biomass

Abstract

Described is a process comprising a series of steps for the production of renewable oil from woody biomass. This oil can be processed directly by a traditional petroleum refinery producing transportation fuels or other similar downstream petroleum products. The cellulosic fraction, substantially reduced in lignin can be used in various downstream processing. The method involves a series of steps: step one, comminuting woody biomass to pass a #20 screen mesh size; step 2, mixing the pulverized material with ethanol, elevating the temperature of the mixture at atmospheric pressure, then subjecting the mixture to high shear (which comprises a pretreatment step); step 3, elevation of the wood/ethanol mixture to supercritical conditions, while mixing. Step 4, recovers the ethanol for reuse via distillation. The resulting oil contains lignin, solid cellulose, and carbohydrate derivatives. After filtration to remove the cellulosic fraction in Step 5, the water soluble materials are removed in a counter current wash to purify the hydrophobic oil. The resulting products are a hydrophobic free flowing oil, cellulose, and carbohydrate derived water soluble stream. Applications of the products include co-firing and co-processing of the oil with hydrocarbon streams, use of the cellulose in biochemical conversion, and solid products. The aqueous carbohydrate stream can provide sufficient energy to supply the entire process via anaerobic digestion to biogas to generate heat and electricity.

What is claimed is: 
     
         1 . A method for the production of renewable oil from woody biomass comprising the steps:
 a. Creating a quantity of woody biomass containing cellulosic material for treatment by processing chipped wood to a fine size, passing a 20 mesh screen, thereby;   b. Treating the woody biomass by combining in a wetting tank the 20 mesh size woody biomass with ethanol and water in the approximate ratio of 1:8 ethanol to water, creating a wetted woody biomass;   c. Transferring the wetted woody biomass into a high shear mixing tank, in a continuous stream through a heat exchanger, heating the wetted woody biomass to approximately 65° C.;   d. In the high shear mixing tank, reducing the size of the wetted woody biomass to a size sufficiently small to allow the ethanol to penetrate into a plurality of pore spaces previously occupied by the water, creating a high sheared mixture;   e. Transferring the high sheared mixture to a supercritical extraction vessel operating at approximately 285° C. and 2100 psi and mixing for approximately 15 min to 30 min creating a supercritical mixture;   f. Transferring the supercritical mixture through a heat exchanger to lower the temperature to approximately 40° C. and to lower the pressure to approximately atmospheric pressure, creating a cooled mixture;   g. Passing the cooled mixture through a 0.5-micron absolute filter bed to remove cellulosic material (wood fibers) from the cooled mixture, creating a filtered mixture, said filtered mixture containing ultrafine cellulosic materials smaller than 0.5 micron;   h. Removing from the filtered mixture at least some ultrafine cellulosic materials utilizing a centrifuge or cyclone, creating an oil/ethanol/water mixture.   i. In a vacuum distillation column, recovering ethanol and water and creating an oil stream;   j. In a counter current water washing column operating at a ratio of approximately 10 parts washing water to 1 part oil stream, removing from the oil stream unwanted impurities including sugar, metals and, phenols, creating a water washed oil stream; and,   k. Feeding the water washed oil stream into a second vacuum distillation column and removing washing water from the water washed oil stream whereby the washing water comprises less than 0.5% of the washed oil stream.   
     
     
         2 . Renewable oil produced by the method according to  claim 1 .