Robert Haber

One Accord Food Pantry, Inc.

Troy, New York

CONTENTS

Introduction………………………………………………………………………………………………….. 250

The Project — Phase 1………………………………………………………………………………….. 251

Alcohol Fuel………………………………………………………………………………………. 251

Municipal Solid Waste (MSW) Fuel — Wood and Cardboard…………. 251

Carbon-Cycle Neutral……………………………………………………………… 251

Procedure…………………………………………………………………………………. 252

Potential Savings……………………………………………………………………… 252

Aquaponics……………………………………………………………………………………….. 252

Fish Produced………………………………………………………………………….. 253

Auto-Feeders……………………………………………………………………………. 253

Roof of the Structure………………………………………………………………. 254

Floor of the Structure………………………………………………………………. 254

Balanced Diet………………………………………………………………………….. 255

Efficient Use of Water…………………………………………………………….. 255

Power Generation…………………………………………………………………….. 255

Potential Yield…………………………………………………………………………. 255

Smaller Family-Sized Unit……………………………………………………….. 256

Bacteria Production…………………………………………………………………. 256

Fish Feed Formulation………………………………………………………………………. 256

Fish Hatchery and Seedling Greenhouse…………………………………………… 257

Hatchery………………………………………………………………………………….. 257

Greenwater System………………………………………………………………….. 258

Seedling Greenhouse……………………………………………………………….. 258

Energy Plantation……………………………………………………………………………… 258

Compost……………………………………………………………………………………………. 259

Processing…………………………………………………………………………………………. 259

Technology Transfer — Website………………………………………………………. 260

The Project — Phase 2………………………………………………………………………………….. 260

Abundance of Biomass……………………………………………………………………. 260

Saving Family Farms………………………………………………………………………… 261

Food Imported into the Northeast……………………………………………………. 261

Reserve Food Supply………………………………………………………………………… 261

Energy Plantation……………………………………………………………………………… 262

Growth of Fish Feed from Plant Sources………………………………………….. 262

Compost-Based Aquaponic Greenhouses………………………………………… 263

Using Vertical Space — Potatoes in Scrap Tires and

Strawberries…………………………………………………………………………….. 263

References…………………………………………………………………………………………………….. 264

INTRODUCTION

The evolution of this project took a period of over 20 years. Originating in the pre-Reagan era of what we once thought were high gasoline prices, the concept was to simply make ethanol for electric or transportation use and feed the by­products to pigs and chickens. This still left remaining waste to manage, however. With the change of politics and policies, all federal grants for alcohol research were cancelled. As a result, the concept went unfulfilled for 20 years. But the world is a different place now. Today, the concept has evolved to design and implement a zero-discharge, closed, recirculating, environmentally isolated sys­tem, which produces microelement-enhanced, high-quality protein food using municipal solid waste as a source for nonpetroleum power generation. After having been the 13-year director of a rural food pantry, which met the emergency food needs of over 40,000 rural needy a year (half of whom were children), I enjoyed a unique perspective of the massive amounts of food waste that are discarded daily, especially breads and bakery sweets. As a resource for this project, the huge quantity of useable bakery waste was staggering and dictated the type of fuel to be made. At issue for the project were not only the need to generate heat and electricity, but also the need to have an ingredient base for on­site manufactured fish feed. These three expenses (heat, electric, and feed) com­prise the bulk of all operating expenses associated with the long-term success or failure of the project. Reducing or eliminating these expenses would then enhance the economic viability and potential success of the project. Of critical importance were the ingredients for the feed, since it was the only nutrient input into the system for both fish and plants. Only one type of fuel met all three needs — ethanol — and in particular, ethanol from bakery waste. Additionally, and for the purposes of this project, were the by-products of fermentation (carbon dioxide and DDGS (distillers dried grains and solubles)) and combustion (carbon dioxide and water vapor). The following is an in-depth description of the project.

THE PROJECT — PHASE 1

The first phase of this project is composed of the following subsystems:

1. Alcohol fuel.

2. Solid MSW fuel — wood and cardboard.

3. Aquaponics.

4. Fish feed formulation.

5. Fish hatchery.

6. Energy plantation.

7. Compost.

8. Processing.

9. Technology transfer — website.

Preface

In the 1880s, Henry Ford developed a prototype automobile (the quadracycle) that could be operated with ethanol as fuel. Historians say that Ford always believed that the Model T and his future cars would use alcohol as fuel because it was a renewable energy source and would boost the agricultural economy. Over a century later, research has finally brought us to the point at which using alcohol-based fuels for transportation applications is a reality. Over the last two decades, research on alcoholic fuels as alternative and renewable energy sources has exponentially increased. Some of these alcoholic fuels (e. g., methanol and ethanol) have been introduced into the market as alcohol-gasoline blends for combustion engines, but research has also focused on employing these alcohols as fuels for alternative energy platforms, such as fuel cells. This book will provide a comprehensive text to discuss both the production of alcoholic fuels from various sources and the variety of applications of these fuels, from combustion engines to fuel cells to miniature power plants (generators) for farms.

Currently, there is no text on alcoholic fuels. The books on the market that come close are Biomass Renewable Energy, Fuels, and Chemicals (1998) and Renewable Energy: Sources for Fuels and Electricity (1992). Neither of these texts focuses on alcoholic fuels. Both books focus on the production of all renewable energy sources and have sections on the production of alcoholic fuels, but they do not include the necessary information to see the history and future of alcoholic fuels from both production and application viewpoints. This book is comprised of edited chapters from experts and innovators in the field of alcohol fuels. The book is broken down into three sections. The first section focuses on the production of methanol, ethanol, and butanol from various biomasses includ­ing corn, wood, and landfill waste. The second section focuses on blended fuels. These are the fuels that mix alcohols with existing petroleum products, such as gasoline and diesel. The final section focuses on applications of alcoholic fuels. This includes different types of fuel cells, reformers, and generators. The book concludes with a chapter on the future of alcohol-based fuels. The book is intended for anyone wanting a comprehensive understanding of alcohol fuels. Each chapter has sufficient detail and provides scientific references sufficient for researchers to get a detailed perspective on both the production of alcoholic fuels and the applications of alcoholic fuels, but the chapters themselves are compre­hensive in order to provide the reader with an understanding of the history of the technology and how each application plays an important role in removing our dependency on oil and environmentally toxic power sources, such as batteries. The book is intended to be a supplementary text for graduate courses on alter­native energy, power sources, or fuel cells. There are books on each of these subjects, but no book that ties them together. To really understand alcohol-based fuel cells, you need a thorough understanding of how the alcohol is produced and purified. On the other hand, a scientist whose focus is on improving the production of ethanol needs to have a thorough understanding of how the alcohol is being used.

Shelley D. Minteer

Saint Louis University, Missouri

CONTENTS

Introduction………………………………………………………………………………………………………. 1

Methanol…………………………………………………………………………………………………………… 2

Ethanol……………………………………………………………………………………………………………… 3

Butanol……………………………………………………………………………………………………………… 3

Propanol……………………………………………………………………………………………………………. 4

Conclusions………………………………………………………………………………………………………. 4

References………………………………………………………………………………………………………… 4

Abstract Alcohol-based fuels have been used as replacements for gasoline in combustion engines and for fuel cells. The four alcohols that are typically used as fuels are methanol, ethanol, propanol, and butanol. Ethanol is the most widely used fuel due to its lower toxicity properties and wide abundance, but this chapter introduces the reader to all four types of fuels and compares them.

INTRODUCTION

Alcohol-based fuels have been important energy sources since the 1800s. As early as 1894, France and Germany were using ethanol in internal combustion engines. Henry Ford was quoted in 1925 as saying that ethanol was the fuel of the future [1]. He was not the only supporter of ethanol in the early 20th century. Alexander Graham Bell was a promoter of ethanol, because the decreased emission to burning ethanol [2]. Thomas Edison also backed the idea of industrial uses for farm products and supported Henry Ford’s campaign for ethanol [3]. Over the years and across the world, alcohol-based fuels have seen short-term increases in use depending on the current strategic or economic situation at that time in the country of interest. For instance, the United States saw a resurgence in ethanol fuel during the oil crisis of the 1970s [4]. Alcohols have been used as fuels in three main ways: as a fuel for a combustion engine (replacing gasoline), as a fuel additive to achieve octane boosting (or antiknock) effects similar to the petroleum-based additives and metallic additives like tetraethyllead, and as a fuel for direct conversion of chemical energy into electrical energy in a fuel cell.

Alcohols are of the oxygenate family. They are hydrocarbons with hydroxyl functional groups. The oxygen of the hydroxyl group contributes to combustion. The four most simplistic alcoholic fuels are methanol, ethanol, propanol, and butanol. More complex alcohols can be used as fuels; however, they have not shown to be commercially viable. Alcohol fuels are currently used both in com­bustion engines and fuel cells, but the chemistry occurring in both systems is the same. In theory, alcohol fuels in engines and fuel cells are oxidized to form carbon dioxide and water. In reality, incomplete oxidation is an issue and causes many toxic by-products including carbon monoxide, aldehydes, carboxylates, and even ketones. The generic reaction for complete alcohol oxidation in either a combus­tion engines or a fuel cell is

CxH2x+2 O + (~)O2 ^ XCO2 + (X + 1)H2О

It is important to note this reaction occurs in a single chamber in a combustion engine to convert chemical energy to mechanical energy and heat, while in a fuel cell, this reaction occurs in two separate chambers (an anode chamber where the alcohol is oxidized to carbon dioxide and a cathode chamber where oxygen is reduced to water.)

Methanol (also called methyl alcohol) is the simplest of alcohols. Its chemical structure is CH3OH. It is produced most frequently from wood and wood by­products, which is why it is frequently called wood alcohol. It is a colorless liquid that is quite toxic. The LD50 for oral consumption by a rate is 5628 mg/kg. The LD50 for absorption by the skin of a rabbit is 20 g/kg. The Occupational Safety and Health Administration (OSHA) approved exposure limit is 200 ppm for 10 hours. Methanol has a melting point of -98°C and a boiling point of 65°C. It has a density of 0.791 g/ml and is completely soluble in water, which is one of the hazards of methanol. It easily combines with water to form a solution with minimal smell that still has all of the toxicity issues of methanol. Acute methanol intoxication in humans leads to severe muscle pain and visual degeneration that can lead to blindness. This has been a major issue when considering methanol as a fuel. Dry methanol is also very corrosive to some metal alloys, so care is required to ensure that engines and fuel cells have components that are not corroded by methanol. Today, most research on methanol as a fuel is centered on direct methanol fuel cells (DMFCs) for portable power applications (replace­ments for rechargeable batteries), but extensive early research has been done on methanol-gasoline blends for combustion engines.

Ethanol (also known as ethyl alcohol) is the most common of alcohols. It is the form of alcohol that is in alcoholic beverages and is easily produced from com, sugar, or fruits through fermentation of carbohydrates. Its chemical structure is CH3CH2OH. It is less toxic than methanol. The LD50 for oral consumption by a rat is 7060 mg/kg [5]. The LD50 for inhalation by a rat is 20,000 ppm for 10 hours [6]. The NIOSH recommended exposure limit is 1000 ppm for 10 hours [7]. Ethanol is available in a pure form and a denatured form. Denatured ethanol contains a small concentration of poisonous substance (frequently methanol) to prevent people from drinking it. Ethanol is a colorless liquid with a melting point of -144°C and a boiling point of 78°C. It is less dense than water with a density of 0.789 g/ml and soluble at all concentrations in water. Ethanol is frequently used to form blended gasoline fuels in concentrations between 10-85%. More recently, it has been investigated as a fuel for direct ethanol fuel cells (DEFC) and biofuel cells. Ethanol was deemed the “fuel of the future” by Henry Ford and has continued to be the most popular alcoholic fuel for several reasons: (1) it is produced from renewable agricultural products (corn, sugar, molasses, etc.) rather than nonrenewable petroleum products, (2) it is less toxic than the other alcohol fuels, and (3) the incomplete oxidation by-products of ethanol oxidation (acetic acid (vinegar) and acetaldehyde) are less toxic than the incomplete oxi­dation by-products of other alcohol oxidation.

Butanol is the most complex of the alcohol-based fuels. It is a four-carbon alcohol with a structure of CH3CH2CH2CH2OH. Butanol is more toxic than either meth­anol or ethanol. The LD50 for oral consumption of butanol by a rat is 790 mg/kg. The LD50 for skin adsorption of butanol by a rabbit is 3400 mg/kg. The boiling point of butanol is 118°C and the melting point is -89°C. The density of butanol is 0.81 g/mL, so it is more dense than the other two alcohols, but less dense than water. Butanol is commonly used as a solvent, but is also a candidate for use as a fuel. Butanol can be made from either petroleum or fermentation of agricultural products. Originally, butanol was manufactured from agricultural products in a fermentation process referred to as ABE, because it produced Acetone-Butanol and Ethanol. Currently, most butanol is produced from petroleum, which causes butanol to cost more than ethanol, even though it has some favorable physical properties compared to ethanol. It has a higher energy content than ethanol. The vapor pressure of butanol is 0.33 psi, which is almost an order of magnitude less than ethanol (2.0 psi) and less than both methanol (4.6 psi) and gasoline (4.5 psi). This decrease in vapor pressure means that there are less problems with evaporation of butanol than the other fuels, which makes it safer and more environmentally friendly than the other fuels. Butanol has been proposed as a replacement for ethanol in blended fuels, but it is currently more costly than ethanol. Butanol has also been proposed for use in a direct butanol fuel cell, but the efficiency of the fuel cell is poor because incomplete oxidation products easily passivate the platinum catalyst in a traditional fuel cell.

Although propanols are three carbon alcohols with the general formula C3H8O, they are rarely used as fuels. Isopropanol (also called rubbing alcohol) is fre­quently used as a disinfectant and considered to be a better disinfectant than ethanol, but it is rarely used as a fuel. It is a colorless liquid like the other alcohols and is flammable. It has a pungent odor that is noticeable at concentrations as low as 3 ppm. Isopropanol is also used as an industrial solvent and as a gasoline additive for dealing with problems of water or ice in fuel lines. It has a freezing point of -89°C and a boiling point of 83°C. Isopropanol is typically produced from propene from decomposed petroleum, but can also be produced from fer­mentation of sugars. Isopropanol is commonly used for chemical synthesis or as a solvent, so almost 2M tons are produced worldwide.

CONCLUSIONS

In today’s fuel market, methanol and ethanol are the only commercially viable fuels. Both methanol and ethanol have been blended with gasoline, but ethanol is the current choice for gasoline blends. Methanol has found its place in the market as an additive for biodiesel and as a fuel for direct methanol fuel cells, which are being studied as an alternative for rechargeable batteries in small electronic devices. Currently, butanol is too expensive to compete with ethanol in the blended fuel market, but researchers are working on methods to decrease cost and efficiency of production to allow for butanol blends, because the vapor pressure difference has environmental advantages. Governmental initiatives should ensure an increased use of alcohol-based fuels in automobiles and other energy conversion devices.

REFERENCES

1. Ford Predicts Fuel From Vegetation, The New York Times, Sept. 20, 1925, p. 24.

2. National Geographic, 31, 131, 1917.

3. Borth, C., Chemists and Their Work, Bobbs-Merrill, New York, 1928.

4. Kovarik, B., Henry Ford, Charles F. Kettering and the Fuel of the Future, Automot. Hist. Rev., 32, 7-27, 1998.

5. Toxicology and Applied Pharmacology, Academic Press, Inc., 16, 718, 1970.

6. Raw Material Data Handbook, Vol. 1: Organic Solvents, Nat. Assoc. Print. Ink Res. Inst., 1, 44, 1974.

7. National Institute for Occupational Safety and Health, U. S. Dept. of Health, Education, and Welfare, Reports and Memoranda, DHHS, 92-100, 1992.

Carlo N. Hamelinck

(currently working with Ecofys b. v. Utrecht,

The Netherlands)

Andrn P. C. Faaij

(Utrecht University, Copernicus Institute of Sustainable Development and Innovation, Utrecht, The Netherlands)

CONTENTS

Introduction………………………………………………………………………………………………………. 8

Technology……………………………………………………………………………………………………….. 9

Overview……………………………………………………………………………………………….. 9

Pretreatment………………………………………………………………………………………….. 9

Gasification…………………………………………………………………………………………. 10

IGT Gasifier……………………………………………………………………………….. 10

BCL Gasifier……………………………………………………………………………… 12

Oxygen Supply………………………………………………………………………….. 13

Gas Cleaning and Contaminant Limits………………………………………………. 13

Raw Gas versus System Requirements……………………………………… 13

Tar Removal……………………………………………………………………………… 15

Wet Gas Cleaning………………………………………………………………………. 17

Dry/Hot Gas Cleaning……………………………………………………………….. 19

Gas Conditioning………………………………………………………………………………… 20

Reforming………………………………………………………………………………….. 20

Water Gas Shift…………………………………………………………………………. 22

CO2 Removal…………………………………………………………………………….. 23

Methanol Synthesis…………………………………………………………………………….. 25

Fixed-Bed Technology………………………………………………………………. 26

Liquid-Phase Methanol Production…………………………………………… 27

Options for Synergy………………………………………………………………………………………… 28

Electricity Cogeneration by Combined Cycle…………………………………….. 28

Natural Gas Cofiring/Cofeeding…………………………………………………………. 29

Black Liquor Gasification…………………………………………………………………… 29

Other Biofuels via Gasification…………………………………………………………… 30

Hydrogen…………………………………………………………………………………… 30

Fischer-Tropsch (FT) Diesel……………………………………………………….. 30

Methanol to Diesel…………………………………………………………………….. 31

Methanol to Gasoline………………………………………………………………… 31

Dimethyl Ether (DME)……………………………………………………………….. 31

Techno-Economic Performance……………………………………………………………………… 32

Selection of Concepts…………………………………………………………………………. 32

Modeling Mass and Energy Balances………………………………………………… 33

Costing Method………………………………………………………………………………….. 36

Results………………………………………………………………………………………………… 37

Conclusions……………………………………………………………………………………………………… 44

References……………………………………………………………………………………………………….. 45

INTRODUCTION

Methanol (CH3OH), also known as methyl alcohol or wood alcohol, is the sim­plest alcohol. It can be used as a fuel, either as a blend with gasoline in internal combustion engines[2] or in fuel cell vehicles.[3] Also, methanol has a versatile function in the chemical industry as the starting material for many chemicals.

Methanol is produced naturally in the anaerobic metabolism of many varieties of bacteria and in some vegetation. Pure methanol was first isolated in 1661 by Robert Boyle by distillation of boxwood. In 1834, the French chemists Dumas and Peligot determined its elemental composition. In 1922, BASF developed a process to convert synthesis gas (a mixture of carbon monoxide and hydrogen) into methanol. This process used a zinc oxide/chromium oxide catalyst and required extremely vigorous conditions: pressures ranging from 300-1000 bar, and temperatures of about 400°C. Modern methanol production has been made more efficient through the use of catalysts capable of operating at lower pressures. Also the synthesis gas is at present mostly produced from natural gas rather than from coal.

In 2005, the global methanol production capacity was about 40 Mtonne/year, the actual production or demand was about 32 Mtonne (Methanol Institute 2005). Since the early 1980s, larger plants using new efficient low-pressure technologies are replacing less efficient small facilities. In 1984, more than three quarters of
world methanol capacity was located in the traditional markets of North America, Europe, and Japan, with less than 10 percent located in “distant-from-market” developing regions such as Saudi Arabia. But from that time most new methanol plants have been erected in developing regions while higher cost facilities in more developed regions were being shut down. The current standard capacities of conventional plants range between 2000 and 3000 tonnes of methanol per day. However, the newest plants tend to be much larger, with single trains of 5000 tonnes/day in Point Lisas, Trinidad (start-up in 2004), 5000 tonnes/day in Dayyer, Iran (start-up in 2006), and 5000 tonnes/day in Labuan, Malaysia (start construc­tion in 2006).

Methanol produced from biomass and employed in the automotive sector can address several of the problems associated with the current use of mineral oil derived fuels, such as energy security and greenhouse gas emissions.

This chapter discusses the technology for the production of methanol from biomass. For a selection of concepts, efficiencies and production costs have been calculated.

Overview

Methanol is produced by a catalytic reaction of carbon monoxide (CO), carbon dioxide (CO2), and hydrogen (H2). These gases, together called synthesis gas, are generally produced from natural gas. One can also produce synthesis gas from other organic substances, such as biomass. A train of processes to convert biomass to required gas specifications precedes the methanol reactor. These processes include pretreatment, gasification, gas cleaning, gas conditioning, and methanol synthesis, as are depicted in Figure 2.1 and discussed in Sections 2.2-2.6.

Pretreatment

Chipping or comminution is generally the first step in biomass preparation. The fuel size necessary for fluidized bed gasification is between 0 and 50 mm (Pierik et al. 1995). Total energy requirements for chipping woody biomass are approx­imately 100 kJe/kg of wet biomass (Katofsky 1993) down to 240 kWe for 25-50 tonne/h to 3 x 3 cm in a hammermill, which gives 17-35 kJe/kg wet biomass (Pierik et al. 1995).

The fuel should be dried to 10-15% depending on the type of gasifier. This consumes roughly 10% of the energy content of the feedstock. Drying can be

FIGURE 2.1 Key components in the conversion of biomass to methanol.

done by means of hot flue gas (in a rotary drum dryer) or steam (direct/indirect), a choice that among others depends on other steam demands within the process and the extent of electricity coproduction. Flue gas drying gives a higher flexibility toward gasification of a large variety of fuels. In the case of electricity generation from biomass, the integration in the total system is simpler than that of steam drying, resulting in lower total investment costs. The net electrical system effi­ciency can be somewhat higher (van Ree et al. 1995). On the other hand, flue gas drying holds the risk of spontaneous combustion and corrosion (Consonni et al. 1994). For methanol production, steam is required throughout the entire process, thus requiring an elaborate steam cycle anyway. It is not a priori clear whether flue gas or steam drying is a better option in methanol production. A flue gas dryer for drying from 50% moisture content to 15% or 10% would have a specific energy use of 2.4-3.0 MJ/ton water evaporated (twe) and a specific electricity consumption of 40-100 kWh^twe (Pierik et al. 1995). A steam dryer consumes 12 bar, 200°C (process) steam; the specific heat consumption is 2.8 MJ/twe. Electricity use is 40 kWh/twe (Pierik et al. 1995).