Process for hydrolyzing cellulosic materials

Claim 1

A COMMERCIAL PROCESS OF HYDROLYZING SUBSTANTIALLY AL OF THE CARBOHYDRATE CONTENT OF WOOD TO OBTAIN A READILY FERMENTABLE PENTOSE-RICH SUGAR LIQUOR AND AT LEAST ONE SEPARATE HEXOSERICH LIQUOR SUITABLE FOR CRYSTALLIZATION OF THE GLUCOSE CONTENT THEREOF, SAID PROCESS INCLUDING A PLURALITY OF FIRST LOW TEMPERATURE HYDROLYZING STEPS PERFOMRED AT TEMPERATURES IN THE RANGE ABOVE 155*C. TO BELOW 170*C. AT THE CORRESPONDING PRESSURE WITH AN AQUEOUS PENTOSE SUGAR LIQUOR ADJUSTED TO A CONTENT OF SO2 AS HYDROLYZING AGENT IN AN EFFECTIVE AMOUNT NOT EXCEEDING 2.0%, A PLURALITY OF SECOND LOW TEMPERATURE HYDROLYZING STEPS PERFOMRED AT TEMPERATURES HIGHER THAN THAT OF SAID FIRST LOW TEMPERATURE HYDROLYZING STEPS AND IN THE RANGE ABOVE 155*C. TO BELOW 170*C. AT THE CORRESPONDING PRESSURE WITH AN AQUEOUS HYDROLYZING SOLUTIN CONTAINING SO2 AS HYDROLYZING AGENT IN AN EFFECTIVE AMOIUNT NOT EXCEEDING 2.0%, A PLURALITY OF FIRST HIGH TEMPERATURE HYDROLYZING STEPS PERFORMED AT TEMPERATURES IN THE RANGE ABOVE 170*C. TO 205*C. AT THE CORRESPONDING PRESSURE WITH AN AQUEOUS HEXOSE SUGAR LIQUOR ADJUSTED TO A CONTENT OF SO2, AS HYDROLYZING AGENT, IN AN EFFECTIVE AMOUNT NOT EXCEEDING 2.0%, AND A PLURALITY OF EACH OF A SECOND, A THIRD, AND SO ON HIGH TEMPERATURE HYDROLYZING STEPS EACH OF WHICH IS PERFORMED UNDER CONDITIONS AS DEFINED FOR SAID FIRST HIGH TEMPERATURE HYROLYZING STEPS, THE LIQUID BEING MAINTAINED IN LIVELY CIRCULATION IN EACH OF SAID HYDROLYZING STEPS FOR THE DURATION THEREOF, SAID PROCESS COMPRISING THE STEPS OF PERFORMING A FIRST LOW TEMPERATURE HYDROLYSIS ON A FRESH SECOND BATCH OF SAID WOOD, THE LIQUOR FOR SAID HYDROLYSIS HAVING BEEN DRAWN FROM A SECOND LOW TEMPERAHYDROLYZING STEP ON A FIRST BATCH OF SAID WOOD, WITHDRAWING THE READILY FERMENTABLE PENTOSERICH LIQUOR RESULTING FROM SAID FIRST LOW TEMPERATURE HYDROLYZING STEP SUBSEQUENTLY PERFORMING A SECOND LOW TEMPERATURE HYDROLYZING STEP ON THE PARTIALLY SPENT SECOND WOOD BATCH, WITHDRAWING THE PENTOSE-RICH LIQUOR RESULTING FROM SAID SECOND LOW TEMPERATURE HYDROLYZING STEP AND EMPLOYING SAID RESULTING LIQUOR AS THE AQUEOUS LIQUOR IN A FIRST LOW TEMPERATURE HYDROLYZING STEP PERFORMED ON A FRESH THIRD BATCH OF SAID WOOD, PER FORMING A FIRST HIGH TEMPERATURE HYROLYZING STEP ON SAID SECOND WOOD BATCH EMPLOYING A HEXOSE SUGAR LIQUOR WITHDRAWN FROM A THIRD HIGH TEMPERATURE HYDROLYZING STEP PERFOMRE DON SAID FIRST WOOD BATCH, WITHDRAWING FROM SAID SECOND WOOD BATCH THE HEXOSE-RICH SUGAR LIQUOR RESULTING FROM SAID FIRST HIGH TEMPEATURE HYDROLYZING STEP PERFORMED ON SAID SECOND WOOD BATCH, SAID LIQUOR BEING SUITED FOR CRYSTALLIZATION OF ITS GLUCOSE CONTENT, PERFORMING A SECOND HIGH TEMPERATURE HYDROLYZING STEP ON SAID SECOND WOOD BATCH EMPLOYING AS SUGAR LIQUOR A LIQUOR RESULTING FROM A FOURTH HIGH TEMPERATURE HYDROLYZING STEP ON SAID FIRST WOOD BATCH, WITHDRAWING FROM SAID SECOND WOOD BATCH THE HEXOSE-RICH LIQUOR RESULTING FROM SAID SECOND HIGH TEMPERATURE HYDROLYZING STEP ON SAID SECOND WOOD BATCH, SAID RESULTING LIQUOR BEING SUITED FOR CRYSTALLIZTION OF ITS GLUCOSE CONTENT, PERFORMING A THIRD HIGH TEMPERATURE HYDROLYZING STEP ON SAID SECOND WOOD BATCH EMPLOYING AS HYDROLYZING LIQUOR A LIQUOR RESULTING FROM A FIFTH HIGH TEMPERATURE HYDROLYZING STEP PERFORMED ON SAID FIRST WOOD BATCH, THE ORIGINAL SOURCE OF SAID LIQUOR BEING A WASH PERFORMED ON A SPENT WOOD BATCH PRECEDING IN THE TREATMENT SERIES SAID FIRST WOOD BATCH, WITHDRAWING FROM SAID SECOND WOOD BATCH THE LIQUOR RESULTING FROM SAID THIRD HIGH TEMPEATURE HYDROLYZING STEP PERFORMED ON SAID SECOND WOOD BATCH AND EMPLOYING SAID WITHDRAWN RESULTING LIQUOR IN A FIRST HIGH TEMPERATURE HYDROLYZING STEP PERFORMED ON SAID THIRD WOOD BATCH, AND ONTINUING THE HEREINABOVE DEFINED PATTERN OF OPERATIONS WITH FURTHER HIGH TEMPERATURE HYDROLYZING STEPS, FURTHER SPENT WOOD BATCH WASHING STEPS, AND THE CORRESPONDING NUMBER OF WOOD BATCHES UNTIL SUBSTANTIALLY THE TOTAL AMOUNT OF CABOHYDRATE IN ALL OF SAID WOOD HAS BEEN HYDROLYZED.