ABSTRACT
Trevor H. Treasure, Hasan Jameel, Richard B. Phillips, Hou-min Chang, Yongcan Jin, and Bon Wook Koo
CONTENTS
Part I: Pretreatment Technology Development......................................................................... 94 4.1 Introduction .......................................................................................................................... 94 4.2 Materials and Methods ....................................................................................................... 95
4.2.1 Materials .................................................................................................................... 95 4.2.2 Substrate Preparation and Pretreatment .............................................................. 95 4.2.3 Enzymatic Hydrolysis ............................................................................................. 96
4.3 Results and Discussion ....................................................................................................... 96 4.3.1 Prehydrolysis ............................................................................................................ 96 4.3.2 Sodium Carbonate Pretreatment ........................................................................... 97 4.3.3 GL Pretreatment ....................................................................................................... 98 4.3.4 Prehydrolysis GL Pretreatment ........................................................................... 100
4.4 Conclusions ......................................................................................................................... 102 Part II: Posttreatments to Reduce Enzyme Charge ................................................................ 103 4.5 Materials and Methods ..................................................................................................... 104
4.5.1 Posttreatments (Additional Treatments Before Enzymatic Hydrolysis) ........ 104 4.6 Results and Discussion ..................................................................................................... 104
4.6.1 Improvement of Enzymatic Hydrolysis by Posttreatments ............................. 104 Part III: Process and Economic Analysis .................................................................................. 109 4.7 Introduction ........................................................................................................................ 109 4.8 Technical Approach ........................................................................................................... 110
4.8.1 Model for Delivered Cost of Biomass ................................................................. 110 4.8.2 Model for the Capital Investments Required to Produce Ethanol Using
the GL Process (Greeneld and Repurposed Kraft Mill Basis) ...................... 110 4.8.3 Process Simulation of GL Pretreatment (GL)–Oxygen Delignication (OD)–Rening (R) and Enzyme Hydrolysis (EH) [GL-OD-R-EH] ...............113 4.8.4 Integration of Tasks 1-3 into a Financial Investment Model ........................... 115
4.8.4.1 Greeneld Assumptions ........................................................................ 115 4.8.4.2 Repurposing Assumptions .................................................................... 116
4.9 Results and Discussion ..................................................................................................... 116 4.9.1 Biomass Cost ........................................................................................................... 116 4.9.2 Capital Investment ................................................................................................. 116
The North American pulp and paper industry is in decline due to falling demand for paper and board products and, in some cases, loss of market pulp share to lower-cost countries. As a result, more than 15 million tons of capacity has been permanently closed. At the same time as this decline in paper products, interest in biomass-to-biofuel has grown to unprecedented levels. Therefore, it would appear to be very attractive to repurpose kraft pulp mills to produce ethanol. In concept, repurposing features a number of signicant advantages over other approaches to bioethanol production:
• A supply chain to grow, harvest, and deliver biomass is already in place, therefore avoiding new demand which might create price pressure on the raw material.
