Biofuels: By Group 7 – May 07, 2018 Mamba, Rhea Manaligod, Laica Maquera Kricel-mae Maruquin, Elha

BIOFUELS

By Group 7 – MAY 07, 2018 Mamba, Rhea Manaligod, Laica Maquera Kricel-Mae Maruquin, Elha

CONTENTS What are Biofuels? Biofuels vs Fossil Fuels History of Biofuels Classification of Biofuels Biofuel’s Main Production Processes 1st Generation Biofuels 2nd Generation Biofuels

3rd Generation Biofuels 4th Generation Biofuels

WHAT ARE BIOFUELS?

Biofuels are fuels derived from biomass. Biomass (biological matter) is an organic matter taken from or produced by plants and animals. It comprises mainly wood, agricultural crops and products, aquatic plants, forestry products, wastes and residues, and animal wastes.

BIOFUELS All types of solid, gaseous and liquid fuels that can be derived from biomass.

1 SOLID FUELS  Wood  Charcoal  Bagasse

2 LIQUID FUELS  Methanol  Ethanol  Plant oils  Methyl esters

3 GASEOUS FUELS  Methane gas  Producer gas

Biofuels vs Fossil Fuels

B

F

Biofuels

Fossil Fuels

Renewable and Sustainable

Nonrenewable energy sources

Cheap

High market price

Fossil fuels such as gasoline are

Have high efficiency

added to biofuels to add to their efficiency Are carbon neutral, i.e. they absorb

Release greenhouse gases, such as the

whatever amount of carbon dioxide

carbon dioxide and carbon monoxide,

they produce, and thus do not add to in the atmosphere. the atmospheric concentration of carbon dioxide Note: The advantages, disadvantages and benefits of biofuels, however, depend on the categorization of the specific biofuel, type of feedstock used and technology applied to produce it.

Biofuels

Figure 1: Substitutability of various biofuels for common petroleumderived fuels.

Biofuels

Figure 2: Greenhouse gas emission of various fuels

Biofuels

Figure 3: Energy usage in the road transport sector 2015, preliminary statistics.

Classifications of Biofuels

Figure 4: General Classification of Biofuels

Classification of Biofuel

01

03

02

SOLID FUELS

LIQUID FUELS GASEOUS FUELS

LIQUID BIOFUELS BIODIESEL

Biodiesel is used as a petroleum diesel replacement

01 02 BIOETHANOL

Bioethanol is used as a gasoline replacement

Liquid Biofuels

Figure 5: Sources of main liquid biofuels for automobiles

Liquid Biofuels

Figure 6: Distribution of ethanol and biodiesel production by country/region in 2011

LIQUID FUELS

BIO-ALCOHOLS The alcohols such as bioethanol, propanol and butanol are produced by microbial fermentation of sugars or starches, derived from feedstocks of wheat, corn, sugar beet, sugarcane, molasses, potato, etc. In the first step complex sugars are hydrolysed and glucose released undergo second fermentation step carried out by yeasts such as Saccharomyces cerevisiae producing ethanol and carbon dioxide. Further diluted ethanol undergo distillation to obtain highly concentrated ethanol in the final step

BIO-ALCOHOLS 2

1

3

BIOETHANOL

PROPANOL

BUTANOL

Ethanol is the most widely used biofuel with 13 billion gallons produced and consumed in 2010 all primarily from corn.

Propanol contains 3 C-C bond that require higher energy to break. As a consequence, the temperature and reaction time of the process will increase.

Butanol (C4H9OH) formed by ABE fermentation (acetone, butanol, and ethanol) is a better biofuel as it will produce more energy and allegedly can be burned "straight" in existing gasoline engines without modification to the engine or car and is less corrosive and less water soluble

LIQUID FUELS BIODIESEL Biodiesel is produced mainly by transesterification of fatty acids of lipids (vegetable oils or aimal fat) with alchol to form a mix of fatty acid alkyl esters (FAAE). The characteristics of the biodiesel concerned from ethanol or methanol are very similar, but methanol is the preferred alcohol despite its toxicity and fossil fuel origin because of its low cost and wide availability.

Biodiesel can be used in any diesel engine either in pure form or mixed with mineral diesel (eg.B20 means blending of 20 percent biodiesel to diesel).

Fuel Type

Feedstock

Conversion Technology Hydroprocessing

Green Diesel

Vegetable oil Animal fat Grease

Fischer Tropsh (FT) Diesel

Lignocellulosic Gasification and biomass FT synthesis

Bio-DME Lignocellulosic Gasification and (Dimethyl biomass DME-synthesis Ether)

Description Biomass oils conversion to diesel and other hydrocarbons via hydrotreating methods as in petroleum refinery

Benefits

Low sulfur diesel. Capital and operating costs could be substantially lower than those for transesterification. Gasification to produce syngas, FT diesel can which is then cleaned and substitute directly purified. The clean syngas then conventional diesel undergoes a catalytic process to with lower synthesize hydrocarbons and emissions. Feedstock their oxygen derivatives by the flexibility. controlled reaction of hydrogen and carbon monoxide. The product is separated and upgraded. Bio-DME is produced from Bio-DME can be used syngas by means of oxygenate as a fuel in diesel synthesis. engines; the process is highly efficient and permits a large scale production. It doesn't corrode metals.

Issues/Challenges

Status

Feedstock availability.

Early stage of commercialization in Brazil by Petrobras; NESTE in Finland is constructing a plant

Gasification requires dried biomass. High level of syngas cleanup required. Catalysts sensitive to poisoning and sintering. Requires improved yields.

Demonstrational facilities underway in Germany, Austria, Finland.

Bio-DME can't be blended with fossil diesel and it has a low energy content (half that of diesel). Can affect certain plastics and rubbers.

Pilot plants under development in Sweden; R&D in China

Straight Vegetable oil vegetable Animal fat oil (SVO) Grease

Mechanical pressing or solvent extraction

Filtering out particles and removing water

Biodiesel Algae Green Diesel

Transesterificatio n or catalytic hydroprocessing

Lipids are derived from microalgae and biodiesel is produced using conventional transesterification technology. Alternatively, the oils can be used to produce “green” diesel via catalytic hydroprocessing .

Viable fuel for tropical regions where saturated oils are available. Coconut oil can be blended directly with diesel and used in unmodified engines in tropical regions High yield per acre; could be used for CO2 capture and reuse.

Not suitable for use Commercial (The in regular diesel Philippines, Papua engines (except New Guinea, EU) coconut oil and other saturated oils).

High cost

R&D programs in the US, Japan, New Zealand, South Africa, and Western Europe

GASEOUS FUELS BIOGAS Biogas consists of methane and carbon dioxide produced by process of anaerobic digestion of organic material by anaerobic microorganisms. This is used as an energy source and the solid byproduct, digestate, is used as an organic fertilizer. The biogas can be produced from any waste with organic fraction in comparison to ethanol ad biodiesel production from crops. The net energy yield per hectare per year is also comparatively higher. The biogas could be even produced from the by-products and waste released from the current bioethanol and biodiesel industries

Methane Gas

GASEOUS FUELS SYNGAS Syngas is a mixture of carbon monoxide, hydrogen and other hydrocarbons produced by partial combustion of biomass, that is, the burning with a volume of oxygen that is not sufficient to transform the biomass waste completely to carbon dioxide and water. Syngas may be burned directly in internal combustion engines, turbines or hightemperature fuel cells. Syngas can be utilized to produce methanol, DME, and hydrogen, or converted via the FischerTropsch process to produce a diesel substitute or a mixture of alcohols that can be blended into gasoline.

GASEOUS FUELS BIOHYDROGEN H2 can be used either as the fuel for direct combustion in an internal combustion engine or as the fuel for a fuel cell. Carbohydrate rich, nitrogen deficient solid wastes such as cellulose and starch containing agricultural and food industry wastes and some food industry wastewaters such as cheese whey, olive mill and bakers yeast industry wastewaters can be used for hydrogen production by using suitable bio-process technologies.

SOLID FUELS

DENSIFIED FUELS When the raw material is already in a suitable form (i.e. firewood), it can burn instantly in a stove or furnace to produce heat or steam. The other kinds of densification are bigger in size compared to wood pellet and are compatible with a wide variety of input feedstocks.

BIOCHAR Biochar is one of the product of pyrolysis and is often used to pre-dry biomass feedstock or sold as charcoal briquettes. Its high stability against decay and ability to retain more plant nutrients as compared to other forms of organic matter made the biochar as a good soil amendment.

SOLID FUELS

Figure 7: Graphical representation of biochar production process. .

BIOFUEL’S MAIN PRODUCTION PROCESSES

Chemical Conversion Process Thermochemical Conversion Process

1  TRANSESTERIFICATION

Biochemical Conversion Process

3

2  GASIFICATION  PYROLYSIS  LIQUEFACTION

 ANAEROBIC DIGESTION  FERMENTATION

CHEMICAL CONVERSION PROCESS TRANSESTERIFICATION Transesterification is a well-known chemical reaction between an ester and an alcohol to produce a new ester and a new alcohol. Thus, during the reaction, there is an exchange of the organic groups R’ of an ester with the group R’’ of an alcohol. These reactions are often catalyzed by an acid or base catalyst.

In the alkali process, sodium hydroxide (NaOH) or potassium hydroxide (KOH) is used as a catalyst along with methanol or ethanol. Initially, during the process, alcoxy is formed by reaction of the catalyst with alcohol and the alcoxy is then reacted with any vegetable oil to form biodiesel and glycerol. The alcoxy reaction is as follows: R-CH2OH + NaOH → H2O + R-CH2ONa

THERMOCHEMICAL CONVERSION PROCESS

In thermo-chemical conversion, heat and chemicals are used to break biomass into syngas (a mixture of carbon monoxide and hydrogen) and reassemble it into products such as ethanol. Table 1: Operational Conditions of Thermochemical Process

GASIFICATION

Gasification converts fossil or non-fossil fuels into useful gases and chemicals. Biomass gasification is the conversion of a carbon-rich lignocellulosic material under oxygen-reduced conditions and high temperatures. The output gas that results is referred to as producer gas, consisting of carbon monoxide (CO), hydrogen (H2), methane (CH4), nitrogen (N2), carbon dioxide (CO2), and small amounts of higher hydrocarbons and inorganic contaminants.

4 Main Steps of Gasification Heating and Drying

02

Pyrolysis Solid-Gas Reactions

Gas Phase Reaction

04

03

01

4 Main Steps of Gasification

Heating and Drying Heating and drying are endothermic processes that require the aid of a gasification agent. Although it is possible to gasify wet feedstocks such as manure and greenwood, some amount of drying of the biomass before gasification is highly desirable. Pyrolysis Pyrolysis produces the intermediate gases (mainly CO, CO2, H2, and light hydrocarbons) and condensable vapor (including water, methanol, acetic acid, acetone, and heavy hydrocarbons).

4 Main Steps of Gasification

Solid-Gas Reactions These reactions (exothermic and endothermic) convert solid carbon into gaseous CO, H2, and CH4.

.

Gas Phase Reaction Includes water-gas shift reaction and methanation

PYROLYSIS

Pyrolysis is the thermal decomposition of organic compounds in the absence of an oxidizing agent, involving a series of reactions to produce smaller and simpler molecules of liquid (bio-oil), solid (char) and gas, thus inhibiting complete combustion. Liquid phase products result from temperatures ,which are too small to crack all the long chain carbon molecules, resulting in oils, methanol, acetone, and tars, etc. Once all the volatile component has been driven off, the residual biomass is in the form of char which is virtually pure carbon.

PYROLYSIS

Table 2: Typical Operation Conditions of Pyrolysis Process

LIQUEFACTION

 Direct liquefaction consists of the direct conversion of biomass into a liquid fuel, omitting the gaseous phase. Hydrothermal liquefaction involves the reaction of biomass in water at elevated temperatures (300oC – 400oC) and pressure (5-20 MPa), usually without the presence of a catalyst. The other liquefaction process dissolves biomass in organic solvents (solvolysis) with or without a catalyst at moderate temperatures (100oC – 250oC) and atmospheric pressure. During chemical liquefaction, biomass components mixed with solvents and a small amount of a catalyst are broken into smaller molecular fragments that can re-polymerize into oily compounds with various ranges of molecular weights.

BIOCHEMICAL CONVERSION PROCESS 1 Anaerobic Digestion

2 Fermentation

Anaerobic digestion involves the breakdown of biodegradable materials by microorganisms in the absence of oxygen.

Microbial fermentation is an efficient and extensively used method for biofuels production. It includes bioethanol, biobutanol, biohydrogen, etc.

ANAEROBIC DIGESTION METHANOGENESIS The methane-forming bacteria convert acetates to methane, carbon dioxide, and alkaline water. Additionally, H2 and CO2 formed in the previous steps are converted to CH4. About 30% of the total methane is produced by this route

ACETOGENESIS Acetogenesis where acid bacteria form acetate, CO2 and H2.

ACIDOGENESIS Acid-forming bacteria promote the decomposition of the previous products into organic acids, carbon dioxide, hydrogen sulfide (H2S), and ammonia (NH3).

HYDROLYSIS Hydrolysis by anaerobic microorganisms use enzymes to break down high molecular organic substances such as proteins, carbohydrates, and fats into low molecular compounds like amino acids, sugars, and fatty acids, respectively, with production of hydrogen and carbon dioxide. .

FERMENTATION

Ethanol, butanol, and methanol are produced principally from energy crops such as sugarcane, maize, beets, yam, or sweet sorghum. A variety of microorganisms ferment sugars into ethanol i.e. Saccharomyces cerevisiae, Pichia stipitis, Candida shehatae and Pachysolan tannophilus, etc. The ethanol recovery is done by distillation and concentrated in a rectifying column to a 95%. Anhydrous ethanol (99.0 %), can be mixed with gasoline and used as fuel.