Sugarcane Juice Extraction and Preservation, and Long-Term Lime Pretreatment of Bagasse
Total Page：16
File Type：pdf, Size：1020Kb
SUGARCANE JUICE EXTRACTION AND PRESERVATION, AND LONG-TERM LIME PRETREATMENT OF BAGASSE A Dissertation by CESAR BENIGNO GRANDA COTLEAR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2004 Major Subject: Chemical Engineering © 2004 CESAR BENIGNO GRANDA COTLEAR ALL RIGHTS RESERVED SUGARCANE JUICE EXTRACTION AND PRESERVATION, AND LONG-TERM LIME PRETREATMENT OF BAGASSE A Dissertation by CESAR BENIGNO GRANDA COTLEAR Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by: _____________________________ _____________________________ Mark T. Holtzapple Richard R. Davison (Co-Chair of Committee) (Co-Chair of Committee) _____________________________ _____________________________ M. Sam Mannan Cady R. Engler (Member) (Member) _____________________________ Kenneth R. Hall (Department Head) December 2004 Major Subject: Chemical Engineering iii ABSTRACT Sugarcane Juice Extraction and Preservation, and Long-term Lime Pretreatment of Bagasse. (December 2004) Cesar Benigno Granda Cotlear, B.S., Texas A&M University Co-Chairs of Advisory Committee: Dr. Mark T. Holtzapple Dr. Richard R. Davison New technologies, such as an efficient vapor-compression evaporator, a stationary lime kiln (SLK), and the MixAlco process, compelled us to re-evaluate methods for producing sugar from cane. These technologies allow more water and lime to be used, and they add more value to bagasse. Extracting and preserving the sugars, and lime pretreating the bagasse to enhance biodigestibility, all at the same time in a pile, was demonstrated to be unfeasible; therefore, sugar extraction must occur before lime treating the bagasse. Sugar extraction should occur countercurrently by lixiviation, where liquid moves in stages opposite to the soaked bagasse (megasse), which is conveyed by screw- press conveyors that gently squeeze the fiber in each stage, improving extraction. The performance of a pilot-scale screw-press conveyor was tested for dewatering capabilities and power consumption. The unoptimized equipment decreased megasse moisture from 96 to 89%. Simulation of the process suggested that eight stages are necessary to achieve 98% recovery from typical sugarcane. The cumulative power for the screw- press conveyor system was 17.0±2.1 hp·h/ton dry fiber. Thin raw juice preserved with lime for several months showed no sucrose degradation and no quality deterioration, except for reducing sugar destruction. The lime loading needed for 1-year preservation is 0.20 g Ca(OH)2/g sucrose. Shorter times require less lime. After preservation, the juice was carbonated and filtered, and the resulting sludge pelletized. Due to their high organic content, the pellets were too weak for calcination iv temperatures used in the SLK. The organics must be decreased prior to pelletization and sodium must be supplemented as a binding agent. Long-term lime pretreatment of bagasse showed two delignification phases: bulk (rapid) and residual (slow). These were modeled by two simultaneous first-order reactions. Treatments with air purging and higher temperatures (50 – 57oC) delignified more effectively, especially during the residual phase, thus yielding higher cellulase- enzyme digestibilities after 2 – 8 weeks of treatment. At temperatures > 60oC, pure oxygen purging is preferred. Fresh bagasse was of better quality than old bagasse. Treatment with NaOH yielded a larger bulk delignification phase than Ca(OH)2. Long-term lime pulping of bagasse was unsuitable for copy-quality paper, but it was appropriate for strawboard and other filler applications. v To God, whom I love and trust above all things. To my parents, who with their love, patience and encouragement have always kept me from giving up. I am here because of them. My accomplishments are theirs. To my loving wife, Anita, for all her love and support. vi ACKNOWLEDGEMENTS I want to thank my advisor, Dr. Mark Holtzapple, for being my mentor, my friend, and my support. His advice, enthusiasm, patience, and words of encouragement always gave me an optimistic attitude, which was essential for things to run smoothly and to keep me afloat when frustration seemed overwhelming. I want to thank also the rest of my committee, Dr. Richard Davison, Dr. Sam Mannan, and Dr. Cady Engler, for all the advice and help they provided during my preliminary examination as well as during the process of completing this dissertation and final examination. Special thanks go to Terrabon and Altex Technologies for funding these projects. I also wish to thank the people of Terrabon and Gooseneck Co., Jim Lampley, Jim McAdams, Don Angonia, Manuel Gonzalez, and José Robles for all their invaluable help. Thanks go to Randy Marek and Nathan Okonski at the Chemical Engineering Department Machine Shop for all their help and ideas in the construction and repair of some equipment used in my research. Also, I want to thank the people from the W.R. Cowley Sugar House in Santa Rosa, Texas, Mark Nittler, Rafael Gonzalez, Yih-Chuan Wu, and others for providing the sugarcane juice and some of the bagasse used in this research, as well as the quality assessment of the processed sugarcane juice. I want to thank also Dr. Michael Saska and Lee Madsen from the Audubon Sugar Institute at Louisiana State University in Baton Rouge for their help with the sugar and juice analysis and bench-scale crystallization. Finally, I want to thank my entire research group, Sehoon Kim, Guillermo Coward-Kelly, Cateryna Aiello, Vincent Chang, Frank Agbogbo, Susan Domke, Richard Jepson, Piyarat Thanakoses (Jeab), Sally Chang, Maria Elena Almendarez, Xu Li, Li Zhu (Julie), Jonathan O’Dwyer, Zhihong Fu, Hung-wen Yeh, Rocio Sierra, Maxine Jones, all the undergraduate student workers and my laboratory facility neighbors Monjur Hossen from the Food Science Department, Marc Barron, Ernesto Hernandez, Carl Vavra, Duane Wagner, Temur Yunusov and Scott McKenzie from the Food Protein R&D Center, who in one way or another always lent me a helping hand. vii TABLE OF CONTENTS Page ABSTRACT ..................................................................................................................... iii DEDICATION ...................................................................................................................v ACKNOWLEDGEMENTS ..............................................................................................vi TABLE OF CONTENTS................................................................................................ vii LIST OF FIGURES............................................................................................................x LIST OF TABLES ...........................................................................................................xx CHAPTER I INTRODUCTION............................................................................................1 I.1 Rationale .........................................................................................1 I.2 Description of Conventional Sugarcane Processing.......................3 I.3 Impact of the Three New Technologies on the Sugarcane Industry..........................................................................9 I.4 First Approach ..............................................................................10 II SUGARCANE JUICE EXTRACTION .........................................................13 II.1 Introduction .................................................................................13 II.2 Literature Review ........................................................................17 II.3 Experimental Methods.................................................................21 II.4 Results and Discussion ................................................................34 II.5 Conclusions .................................................................................47 II.6 Future Work.................................................................................47 III SUGARCANE JUICE PRESERVATION.....................................................50 III.1 Introduction ................................................................................50 III.2 Literature Review.......................................................................52 III.3 Experimental Methods ...............................................................53 III.4 Conclusions ..............................................................................121 III.5 Future Work .............................................................................123 III.6 Questions and Answers ............................................................124 viii CHAPTER Page IV LONG-TERM LIME PRETREATMENT OF BAGASSE..........................130 IV.1 Introduction..............................................................................130 IV.2 Literature Review.....................................................................133 IV.3 Experimental Methods .............................................................140 IV.4 Conclusions..............................................................................219 IV.5 Future Studies ..........................................................................223 V FINAL CONCLUSIONS – PUTTING IT ALL TOGETHER ....................225 V.1 Operation During Sugarcane Harvest Season ...........................225 V.2 Operation After Sugarcane Harvest Season