BIOMASS DIGESTER WITH TWO LIQUID PHASES AND DRAFT TUBE CIRCULATION

摘要

A method comprises introducing biomass solids to a digester comprising a reactor, a circulation system including a first injector; providing a catalyst-containing digestion medium and an organic solvent layer floating thereon; circulating the medium through the circulation system; flowing gas through the medium; keeping the medium hot enough to digest the solids; and operating the digester such a headspace exists above the solvent. The digester includes a first eductor having an inlet in the headspace, a second eductor having an inlet in the organic layer, and a downdraft tube having an inlet in the digestion medium. A motive fluid flowing from the first injector draws gas from the headspace into the first eductor, a motive fluid flowing from the first eductor draws fluid from the organic layer into the second eductor, and a motive fluid flowing from the second eductor draws fluid from the digestion medium into the downdraft tube.

主权项

1. A method comprising:
a) introducing cellulosic biomass solids to a hydrothermal digestion unit comprising:
i) a reactor;ii) a gas feed line for providing gas to the reactor;iii) a biomass feed system for feeding biomass into the reactor;iv) a fluid circulation system including a fluid inlet, a pump, and at least one fluid injector, wherein at least said fluid inlet and said fluid injector are in fluid communication with said pump and are within said reactor; andv) a screen positioned within the reactor and defining a lower zone therebelow; b) providing a liquid phase digestion medium containing a slurry catalyst in the hydrothermal digestion unit, the slurry catalyst being capable of activating molecular hydrogen; c) providing a layer of organic solvent in the hydrothermal digestion unit, said organic solvent being less dense than and substantially immiscible with said digestion medium, whereby said organic solvent forms an organic layer floating on said digestion medium; d) circulating said liquid phase digestion medium through said fluid circulation system; e) supplying an upwardly directed flow of molecular hydrogen through the cellulosic biomass solids; and f) maintaining the cellulosic biomass solids and slurry catalyst at a temperature sufficient to cause digestion of cellulosic biomass solids into an alcoholic component; g) operating the hydrothermal digestion unit such that the level of the organic layer in said reactor is below the top of the reactor, thereby leaving a gas-filled headspace; h) wherein the hydrothermal digestion unit further comprises:
1) at least one first eductor having a first inlet in the headspace and an outlet below the first inlet;2) at least one second eductor having a second inlet in the organic layer and an outlet below said second inlet end;3) at least one downdraft tube having a third inlet in the digestion medium and an outlet in the lower zone;wherein fluid flowing from said fluid injector entrains gas from said headspace into said first eductor;wherein fluid flowing out of said first eductor draws fluid from said organic layer into said second eductor;wherein fluid flowing out of said second eductor draws fluid from said digestion medium into said downdraft tube, andfluid flowing out of said downdraft tube is discharged into said reactor below said packing material.