Process for preparing a hydrolysed lingnocellulosic material
First Claim
1. A process for the production of substantially dry, hydrolyzed lignocellulosic material from a source thereof which comprises:
- providing and maintaining a primary hydrolysis reaction zone at a temperature and a pressure sufficient to cause and support the hydrolysis of lignocellulosic material therein;
providing saturated steam at said temperature and pressure in said primary hydrolysis zone;
feeding hydrolyzable lignocellulosic material to said primary hydrolysis zone and bringing said lignocellulosic material to said hydrolysis conditions therein;
hydrolyzing said lignocellulosic material in said primary hydrolysis zone by contact with said saturated steam at a sufficient residence time to form a stream comprising steam and hydrolysis products;
bringing said stream to an outlet of said primary hydrolysis zone;
separating substantially hydrolyzed products of said lignocellulose from steam at said outlet, and feeding heated hydrolysis products, substantially separated from steam, to a secondary zone;
maintaining said secondary zone at a pressure lower than the pressure in said primary zone;
providing superheated steam bled from said primary zone in said secondary zone at a temperature and a pressure sufficient to dry said hydrolysis products;
allowing said heated hydrolysis products to flash upon introduction into said lower pressure secondary zone, in effective contact with said superheated steam, whereby reducing the water content of said hydrolysis products and increasing the water content of said superheated steam; and
recovering dried hydrolysis products of said lignocellulose material.
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Accused Products
Abstract
An energy efficient process for hydrolyzing lignocellulosic materials which comprises using a primary system by providing a start-up energy input to operating saturated steam conditions and thereafter operating the primary system with substantially constant energy input, the condition of the hydrolysing saturated steam being controlled by water injection and/or steam bleeding from the primary system. The dwell time of the solids stream in the primary system is controlled by controlling its passage with flashing off of steam into a secondary system where drying occurs together with some small measure of hydrolysis in a lower pressure superheated steam environment, there being an energy input into the secondary system using steam bled from the primary system. The output solids material stream is preferably capable of being self polymerized into a formed shape eg a board.
40 Citations
20 Claims
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1. A process for the production of substantially dry, hydrolyzed lignocellulosic material from a source thereof which comprises:
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providing and maintaining a primary hydrolysis reaction zone at a temperature and a pressure sufficient to cause and support the hydrolysis of lignocellulosic material therein; providing saturated steam at said temperature and pressure in said primary hydrolysis zone; feeding hydrolyzable lignocellulosic material to said primary hydrolysis zone and bringing said lignocellulosic material to said hydrolysis conditions therein; hydrolyzing said lignocellulosic material in said primary hydrolysis zone by contact with said saturated steam at a sufficient residence time to form a stream comprising steam and hydrolysis products; bringing said stream to an outlet of said primary hydrolysis zone; separating substantially hydrolyzed products of said lignocellulose from steam at said outlet, and feeding heated hydrolysis products, substantially separated from steam, to a secondary zone; maintaining said secondary zone at a pressure lower than the pressure in said primary zone; providing superheated steam bled from said primary zone in said secondary zone at a temperature and a pressure sufficient to dry said hydrolysis products; allowing said heated hydrolysis products to flash upon introduction into said lower pressure secondary zone, in effective contact with said superheated steam, whereby reducing the water content of said hydrolysis products and increasing the water content of said superheated steam; and recovering dried hydrolysis products of said lignocellulose material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In the process for the production of substantially dry, hydrolyzed lignocellulosic material from a source thereof which comprises:
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providing and maintaining a primary hydrolysis reaction zone at a temperature and a pressure sufficient to cause and support the hydrolysis of lignocellulosic material therein; providing saturated steam at said temperature and pressure in said primary hydrolysis zone; feeding hydrolyzable lignocellulosic material to said primary hydrolysis zone and bringing said lignocellulosic material to said hydrolysis conditions therein; hydrolyzing said hydrolyzable lignocellulosic material in said primary hydrolysis zone by contact with said saturated steam at a sufficient residence time to form a stream comprising steam and hydrolysis products; bringing said stream to an outlet of said primary hydrolysis zone; separating substantially hydrolyzed products of said lignocellulose from steam at said outlet, and feeding heated hydrolysis products, substantially separated from steam, to a secondary zone; maintaining said secondary zone at a pressure lower than the pressure in said primary zone; providing superheated steam bled from said primary zone in said secondary zone in effective contact with said flashed hydrolysis products at a temperature and a pressure sufficient to substantially dry said hydrolysis products; allowing said heated hydrolysis products to flash upon introduction into said lower pressure secondary zone, whereby reducing the water content thereof and increasing the water content of said superheated steam; recovering said dried hydrolysis products of lignocellulose; the method of controlling the energy in the system which comprises; introducing heat into said primary hydrolysis zone by heat exchange with a heat transfer fluid which has been externally heated; preheating said primary hydrolysis zone by contact with said externally heated fluid for a time sufficient to bring said primary zone to a temperature and a pressure sufficient to support and maintain the hydrolysis of hydrolyzable solid lignocellulosic material; after introduction of said hydrolyzable lignocellulosic material to said primary hydrolysis zone, maintaining said primary hydrolysis zone in substantial energy steady state by at least one of the following means;
contact with further quantities of externally heated heat transfer fluid, addition of liquid water to said primary hydrolysis zone, bleeding steam from said primary hydrolysis zone, and removing solid, hot, hydrolyzed lignocellulosic material from said primary hydrolysis zone;providing at least part of said superheated steam in said second drying zone by flashing steam from the product of said primary hydrolysis zone during transfer thereof from said primary to said secondary zone; and at least partially maintaining the steam in said secondary drying zone in a superheated condition by heating such with a heat exchange fluid, and bleeding superheated steam from said secondary drying zone. - View Dependent Claims (17, 18, 19, 20)
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Specification