Algae Growth for Biodiesel Fuel Production Jalisa ... chemical methods, inventions and processes that

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  • Algae Growth for Biodiesel Fuel Production

    Jalisa Richardson

    MTH 496: Senior Project

    Advisor: Shawn D. Ryan, Asst. Professor, Dept. of Mathematics

    Spring 2017

  • Abstract

    As the world and technology continue to grow, there is an increasing need to develop

    many different forms of energy. For more than 100 years as a planet the typical form of energy

    has been through the burning and consumption of fossil fuels. Fossil fuels are advantageous

    because we have the infrastructure in place to continue advancing this technology and it is easy

    to cultivate. The disadvantages to the burning and consumption of fossil fuels are the negative

    impact on the environment and the fact that this form of energy is not being replaced. With this

    in mind there has been a great push to study and implement the use of renewable energy. There

    are many different ways to do this including the more known solar, wind, and hydroelectric

    power systems. There are also alternative renewable energies such and biomass and biofuel. The

    purpose of this project is to investigate and mathematically model the growth of algae in an

    attempt to use algae as an alternative source of energy. Algae is an excellent alternative energy

    source because it can provide energy in the form of biofuel and it also has the ability to clean

    wastewater by consuming minerals during its growth process. This exploration will be done by

    developing and analyzing ordinary differential equation based models such as the classic

    chemostat model and variations of this model. This paper is organized into several different

    sections including an abstract, background information, a brief literature review of current

    mathematical models, an extension of these models, results, and a brief discussion/conclusion.

  • Introduction

    Since the turn of the century, rising oil prices have enhanced the need for finding

    renewable energy sources that can replace fossil fuel. With that search there has been a

    resurfacing of interest in algae biofuels and the increase of funding to create programs on

    creating algae biofuel. It was this resurgence on wanting to learn about algae biofuels and the

    start of the so-called “green chemistry” movement that helped increase the funding for safe

    alternate methods of fuel.

    The term “green chemistry” was coined by Paul Anastas in 1991 and can be defined as

    “the design of chemical products and processes that are more environmentally friendly and

    reduce negative impacts to human health and the environment.”17 Green chemistry takes a look at

    chemical methods, inventions and processes that are environmentally friendly and work to either

    reduce or eliminate generations of hazardous substances. The concept of green chemistry was

    formally established at the Environmental Protection Agency in response to the Pollution

    Prevention Act of 1990. Green chemistry can be applied to organic chemistry, inorganic

    chemistry, biochemistry, analytical chemistry and even physical chemistry.

    There are 12 principles of green chemistry that were developed by Anastas and John C.

    Warner, which help explain what green chemistry means in practice.16 The 12 principles are:

    • Prevention

    • Atom economy

    • Less Hazardous Chemical Synthesis

    • Designing Safer Chemicals

    • Safer Solvent and Auxiliaries

    • Design for Energy Efficiency

    • Use of renewable feedstock

    • Reduce Derivatives

    • Catalysis

    • Design for Degradation

    • Real-time Analysis for Pollution Prevention

    • Inherently Safer Chemistry for Accident Prevention

  • The principle of “Prevention” states “it is better to prevent waste than to treat or clean up

    waste after it is formed.”16 It is in the best interest of the environment to carry out a synthesis in a

    manner that the waste product is minimum or non-existent. Designers need to take into account

    the nature of the materials that they are using to ensure that it is either as non-toxic as possible or

    uses minimal energy and materials to lessen the environmental and social impacts. The next

    principle, “Atom economy”, states, “Synthetic methods should be designed to maximize the

    incorporation of all materials used in the process into the final product.”16 In other words atom

    economy takes into account the atoms wasted during the chemical processes. The high the atom

    economy the more greener the process is deemed to be. Less Hazardous Chemical Synthesis

    entails “wherever practicable, synthetic methodologies should be designed to use and generate

    substances that possess little or no toxicity to human health and the environment.”16 The goal is

    to avoid using known hazardous materials as a starting point, if there are safer alternatives

    available. In addition to this, having hazardous waste from these chemical processes is

    something that should be avoided, if possible. Designing Safer Chemicals states, “Chemical

    products should be designed to preserve efficacy of function while reducing toxicity.”16

    Designers must aim to product chemical products that fulfill their function while also having

    minimal toxicity to humans. Within this you strive to minimize the toxicity of the materials,

    while maintaining its function and efficiency. To reach this goal you must have an understanding

    on chemistry, toxicology and environmental science.

    Safer Solvents and Auxiliaries states that “The use of auxiliary substances (e.g. solvents,

    separation agents, etc.) should be made unnecessary wherever possible and innocuous when

    used.”16 While solvents are not always avoidable those that are chosen should reduce the energy

  • that is required for a reaction, should have minimal or no toxicity and if possible be recyclable

    with no major impacts on the environment or safety. Design for Energy Efficiency states that

    “Energy requirements should be recognized for their environmental and economic impacts and

    should be minimized. Synthetic methods should be conducted at ambient temperature and

    pressure.”16 It is better to minimize the energy needed to create a chemical product by having

    considerations of the reaction design. By carrying out the reactions at room temperature and

    pressure, removal of solvents, or the process used to remove impurities in the products you can

    increase the energy that is required for the chemical product and by that increase the process’s

    environmental impacts. Use of Renewable Feedstock states that “A raw material or feedstock

    should be renewable rather than depleting wherever technically and economically practicable.” 16

    Products that last beyond their life cycle are often the cause of environmental issues, such as

    petrochemicals and landfills filled with non-recyclable plastics, clothing and other dangerous

    materials. By developing and designing products that will withstand their operating purpose

    while also being renewable that is non-toxic or dangerous to human life and the environment we

    can solve this issue. Reduce Derivatives states that “Reduce derivatives - Unnecessary

    derivatization (blocking group, protection/deprotection, and temporary modification) should be

    avoided whenever possible”. 16 The best way to reduce derivatives is by using enzymes, since

    they often only react with one site of the molecule and leave the rest of it alone. Using this

    method protecting groups are not necessarily required. One of the best examples of the use of

    enzymes that avoid protecting groups is the synthesis of ampicillin and amoxicillin antibiotics.

    Catalysis states, “Catalytic reagents (as selective as possible) are superior to stoichiometric

    reagents.” 16 Catalysts do not get used up when they are used by chemical processes, and because

    of this they can be recycled many time, and they also do not contribute to waste. Using catalysts

  • can enable chemical reactions with higher atom economics and because of this they can allow

    the utilization of reactions that wouldn’t be possible under normal circumstances, but also

    produce less waste. Design for Degradation states that “Chemical products should be designed so

    that at the end of their function they do not persist in the environment and break down into

    innocuous degradation products.” 16 This is an ideal principle because when you have products

    that do not break down once they have fulfilled their use they typically accumulate and remain in

    the environment. Chemical products should be designed in a way that allows them to break down

    into harmless products so they will not contribute to the harm of the environment. ” Real-time

    Analysis for Pollution Prevention states that “Analytical methodologies need to be further

    developed to allow for real- time, in-process monitoring and control prior to the formation of

    hazardous substances.” 16 By monitoring the chemicals when they have a reason we are able to

    help prevent the release of hazardous substances that arise from accidents or unex