Biomass Preprocessing and Pretreatments for Production of Biofuels

Mechanical, Chemical and Thermal Methods

Jaya Shankar Tumuluru, Jaya Shankar Tumuluru

• Editore: CRC Press
• Anno: 2018
• ISBN:
  9781351649773
• Edizione: 1
• Argomento: Ciencias biológicas
• Categoria: Biotecnología

Engineering the physical, chemical, and energy properties of lignocellulosic biomass is important to produce high-quality consistent feedstocks with reduced variability for biofuels production. The emphasis of this book will be the beneficial impacts that mechanical, chemical, and thermal preprocessing methods can have on lignocellulosic biomass quality attributes or specifications for solid and liquid biofuels and biopower production technologies. "Preprocessing" refers to treatments that can occur at a distance from conversion and result in an intermediate with added value, with improved conversion performance and efficiency.

This book explores the effects of mechanical, chemical, and thermal preprocessing methods on lignocellulosic biomass physical properties and chemical composition and their suitability for biofuels production. For example, biomass mechanical preprocessing methods like size reduction (which impacts the particle size and distribution) and densification (density and size and shape) are important for feedstocks to meet the quality requirements for both biochemical and thermochemical conversion methods like enzymatic conversion, gasification, and pyrolysis process. Thermal preprocessing methods like drying, deep drying, torrefaction, steam explosion, hydrothermal carbonization, and hydrothermal liquefaction effect feedstock's proximate, ultimate and energy property, making biomass suitable for both solid and liquid fuel production. Chemical preprocessing which includes washing, leaching, acid, alkali, and ammonia fiber explosion that can enable biochemical composition, such as modification of lignin and hemicellulose, and impacts the enzymatic conversion application for liquid fuels production. This book also explores the integration of these preprocessing technologies to achieve desired lignocellulosic biomass quality attributes for biofuels production.

Contents

Preface

Disclaimer

Acknowledgment

List of Reviewers

1. Why Biomass Preprocessing and Pretreatments?

Jaya Shankar Tumuluru

MECHANICAL PREPROCESSING

2. Conventional and Advanced Mechanical Preprocessing Methods for Biomass: Performance Quality Attributes and Cost Analysis

Jaya Shankar Tumuluru and Neal Yancey

3. Effects of Mechanical Preprocessing Technologies on Gasification Performance and Economic Value of Syngas

Amit Khanchi, Bhavna Sharma, Ashokkumar Sharma, Ajay Kumar, Jaya Shankar Tumuluru and Stuart Birrell

4. Mechanical Fractionation of Biomass Feedstocks for Enhanced Pretreatment and Conversion

Jeffrey A. Lacey

5. Biomass Gasification and Effect of Physical Properties on Products

Sushil Adhikari, Hyungseok Nam and Avanti Kulkarni

6. The Impacts of Biomass Pretreatment Methods on Bio-oil Production

Yang Yue and Sudhagar Mani

THERMAL PREPROCESSING

7. Steam Treatment of Cellulosic Biomass for Pelletization

Shahab Sokhansanj, Hamid Rezaei, Pak Sui (Wilson) Lam, Tang Yong, Bahman Ghiasi and Zahra Tooyserkani

8. Hydrothermal Carbonization (HTC) of Biomass for Energy Applications

S. Kent Hoekman, Amber Leland and Larry Felix

9. Thermal Pretreatment of Biomass to make it Suitable for Biopower Application

Jaya Shankar Tumuluru

10. The Impacts of Thermal Pretreatments on Biomass Gasification and Pyrolysis Processes

Zixu Yang and Ajay Kumar

11. Hydrothermal Liquefaction A Promising Technology for High Moisture Biomass Conversion

Ankita Juneja, Deepak Kumar and Jaya Shankar Tumuluru

CHEMICAL PREPROCESSING

12. Chemical Preprocessing of Feedstocks for Improved Handling and Conversion to Biofuels

John Earl Aston

13. Acid Preprocessing Treatments Benefit for Bioconversion of Biomass for Liquid Fuels and Bioproduct Production

Nick Nagle and Erik Kuhn

14. Compositional and Structural Modification of Lignocellulosic Biomass for Biofuel Production by Alkaline Treatment

Kingsley L. Iroba, Majid Soleimani and Lope G. Tabil

15. Impacts, Challenges, and Economics of Ionic Liquid Pretreatment of Biomass

Jipeng Yan, Ling Liang, Todd R. Pray and Ning Sun

16. Ammonia Fiber Expansion and its Impact on Subsequent Densification and Enzymatic Conversion

Bryan D. Bals and Timothy J. Campbell

Index

CHAPTER 1

Why Biomass Preprocessing and Pretreatments?

Jaya Shankar Tumuluru

750 University Blvd, Energy Systems Laboratory, Idaho National Laboratory, Idaho Falls, Idaho, 83415-3570.

Email: [email protected]

1. Introduction

The 2016 United Nations Framework Convention on Climate Change (UNFCCC) challenged the global reduction of greenhouse gas annual emissions to less than 2°C by 2020 (Tumuluru, 2016). According to Arias et al. (2008), biomass is considered carbon-neutral as the carbon dioxide released during its conversion is still part of the carbon cycle. The use of biomass helps to reduce carbon dioxide emissions and minimize negative impacts on the environment. Physical attributes (i.e., moisture, particle size, and density), rheological properties (i.e., elastic and cohesive), and chemical characteristics (i.e., proximate, ultimate, and energy properties) of raw biomass limits its use at a scale necessary for biofuels applications (Tumuluru, 2016).

2. Biomass Physical and Chemical Properties Limitations for Solid and Liquid Fuels

Biomass energy is produced using thermochemical (i.e., direct combustion, gasification, and pyrolysis), biological (i.e., anaerobic digestion and fermentation), and chemical (i.e., esterification) technologies. Biomass as harvested lacks both the bulk density and energy density necessary for cost-efficient bioenergy production. Also, biomass lacks flowability characteristics that limit its’ ability to move from location to location in existing transportation and handling infrastructures. Compared to fossil fuels, raw biomass has a low bulk density, a high moisture content, a hydrophilic nature, and a low calorific value, which all contribute negatively to logistics and final energy efficiency. The low energy density of biomass, as compared to fossil fuels, results in the requirement of high volumes of biomass to generate a comparable amount of fuels production. These high volumes, in turn, lead to storage, transportation, and feed handling issues at cogeneration, thermochemical, and biochemical conversion plants.

High moisture content in the biomass creates uncertainty in its physical, chemical, and microbiological properties. In general, high moisture raw biomass results in preprocessing, storage, feeding and handling, and conversion challenges. Biomass moisture influences the grinding behavior. According to Tumuluru et al. (2014), it is very challenging to grind high moisture biomass due to its fibrous nature. Also, with the increase in moisture content, the amount of energy needed for grinding increases exponentially, as well as negatively impacting particle size distribution. Higher moisture in the biomass also results in feeding and handling issues due to elastic and cohesive properties, which lead to the plugging of grinder screens, the bridging of particles in the conveyors, and the plugging of the reactors themselves.

High moisture content in the biomass results in variable particle sizes (especially when the particles are less than 2 mm) during grinding. These inconsistent particle sizes may not react consistently, thereby reducing efficiency and increasing the costs of the biofuels’ conversion process. Also, raw biomass is thermally unstable due to high moisture, which results in low calorific values when used in thermochemical processes such as gasification. In terms of chemical composition compared to fossil fuels, biomass has more oxygen than carbon and hydrogen. The changes in chemical composition can result in producing inconsistent products and the formation of condensable tars, which further lead to problems like gas-line blockage. As far as storage is concerned, high moisture in biomass results in loss of quality due to chemical oxidation and microbial degradation.

The variable physical, chemical, and rheological properties of the raw biomass are therefore limiting biorefineries to operate at their designed capacities. Variations in physical properties—moisture content, foreign matter (soil), particle size, and particle size distribution—result in reductions in grinding throughput, equipment wear, plugging during conveyance, and reactor feeding problems. These problems all contribute to a decrease in production capacity, an interruption of normal operations, an increase in preprocessing and conversion costs, and a major reduction in yield. Solving the inherent biomass physical, chemical, and rheological issues, whether within a single-plant dedicated supply chain or via a depot system of distributed commercial feedstock suppliers, are crucial in enabling biorefineries to operate at their designed capacities.

3. Preprocessing or Pretreatments

Whether producing biofuels, biopower, or other bioproducts, all bioenergy industries depend on on-spec biomass feedstocks. Biomass cannot be fed into conversion infeed systems until it undergoes some level of preprocessing, such as size reduction or others. The degree of preprocessing depends on the type of conversion, such as biochemical and thermochemical. Pretreatment or preprocessing helps to alter the physical, rheological, and chemical properties of biomass, making it more suitable for conversion. Figure 1 shows how pretreatment impacts lignocellulosic biomass. Recent studies conducted by Tumuluru et al. (2016) suggest that feedstock supply system unit operations have significant impacts on feedstock quality and cost. The aforementioned authors also suggest that novel harvesting methods and mechanical, chemical, and thermal pretreatment technologies can improve the physical, chemical, and rheological properties of biomass, thereby making them better suited to meet the specification in terms of density, particle size, ash composition, and carbohydrate content for both biochemical an...