Using a surface model to optimize the process of dilute acid hydrolysis of walnut green skin for glucose production

Number of pages: 88 File Format: word File Code: 31826
Year: 2014 University Degree: Master's degree Category: Chemical - Petrochemical Engineering
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    Dissertation for receiving the master's degree "M.Sc."

    Chemical engineering, thermodynamic and synthetic engineering

    Abstract

    In this study, the modeling of dilute acid hydrolysis of walnut green skin as an example of lignocellulosic materials in order to produce fermentable sugar in the bioethanol process is studied. has been Four parameters of temperature, time, acid concentration and solid component at three different levels have been considered as variables and the amount of production of six-carbon sugars such as glucose and five-carbon sugars such as xylan as main products and inhibitory substances such as furfural and acetic acid as side and unwanted products. The reaction was carried out in a steam bath equipped with temperature control and stirrer. Hydrolysis products after neutralization and filtration and dilution have been measured by liquid chromatography [1]. In order to investigate the role of the mentioned four variables in the amount of main and secondary products, it has been studied. Then, considering a two-square equation and using the surface model, they have been modeled to optimize the dilute acid hydrolysis process. The results show that walnut green skin can be a lignocellulosic source for the production of fermentable sugar in the bioethanol process. The concentration of these compounds increases with temperature. Also, the increase in glucose production over time is certain. When the solid content increases, the concentration of glucose and other products also increases. Modeling and hydrolysis conditions can be optimized based on temperature, time, acid concentration and solid concentration.

    Key words:

    surface model - optimization - hydrolysis - dilute acid - walnut green skin - glucose

     

    1-1 What is bioethanol?

    Ethanol with closed formula C2H5OH is from the group of organic alkalis, which is normally a colorless liquid with a special smell. The solubility of ethanol in water is high, so it can be mixed with water in any ratio. Its boiling point is 78.3 and its freezing point is 115. Its relative density at 20 degrees Celsius is 0.78. Alcohols are toxic and ethanol is medically less toxic than other alcohols. Under normal conditions, ethanol is a volatile, flammable, clear and colorless liquid that is soluble in both water and non-polar solvents.

    Bioethanol, which is a carbon fuel, with the formula CH3-CH2-OH (ethyl alcohol) can reduce more than 70% of released greenhouse gases. This fuel has an octane number higher than (108), a wider flammability range, and a higher heat of vaporization than gasoline. Due to the presence of high oxygen, it reduces gas emissions in combustion engines.

    Disadvantages of bioethanol are lower energy density than gasoline (bioethanol has 66% of the energy of gasoline), corrosiveness, less radiation of the burner, lower vapor pressure (makes cold start difficult), miscibility with water and toxicity for ecosystems. Some characteristics are shown in Table 1-1.

    (Tables are available in the main file)

    It goes without saying that higher octane numbers are preferred in internal combustion engines because it reduces cylinder knock.

    Bioethanol has 35% oxygen. The more oxygen the fuel contains, the more complete the combustion and can significantly reduce the production of NOX and suspended particles that are produced during the combustion process. Another advantage of using ethanol is that it can be produced from renewable sources of life, based on cellulosic materials, which are found to a significant extent in nature. Cheap and available materials can be used. Ethanol fuel blends are successfully used in all types of vehicles and engines that require gasoline. The most popular blend for light duty vehicles is known as E85, which contains 85% bioethanol and 15% gasoline.

    Blends with higher concentrations of bioethanol in gasoline are also used. For example, some engines can work on mixtures higher than 85% bioethanol E85.Some countries have tried the biofuel program including both forms of the bioethanol and gasoline mixture program. Three parameters, temperature, time and acid density are considered in three different factors as the variable and the amount of glucose produced that are the main products. The reaction is accomplished in a steam bath that was appointed to temperature control and a mixer. Hydrolysis products are measured after frustration, filtration and dilution by HPLC. The amount of production is tested in 3^4 experiments in order to scrutinize the role of the four variables that are given for determining the amount of the main production. Then they are modeled by using the superficial model to optimize the process of hydrolysis of attenuate acid.

  • Contents & References of Using a surface model to optimize the process of dilute acid hydrolysis of walnut green skin for glucose production

    List:

    Title.................................page

    Abstract..................................1

    Chapter one: Introduction

    1-1 What is bioethanol?.3

    1-2 The necessity of using ethanol. 4

    Chapter two: General

    2-1 Introduction... 7

    2-2 Theory Combustion. 7

    2-2-1 Burning (direct combustion). 7

    2-2-2 Bacterial decay. 7

    2-2-3 Fermentation.      7....

    2-3 Cellulosic waste hydrolysis methods.

    2-4 Raw materials used in bioethanol production..

    2-4-1 Sugar raw materials.8

    2-4-2 Starch raw materials...9

    2-4-3 Cellulosic raw materials (lignocellulose)......9

    2-4-3-1 cellulose..14

    2-7-1 Acidic hydrolysis..............21

    2-7-2 Dilute acid hydrolysis..............................

    2-7-2-1 Byproducts of dilute acid hydrolysis...........25

    2-7-2-1-1 Organic acids..............26

    2-7-2-1-2 Phenolic compounds27.................................

    2-7-2-1-3 fural compounds. 27

    2-7-3 Concentrated Acid Hydrolysis....28

    2-7-4 Enzymatic Hydrolysis..........................30

    2-8 Physical Pre-processing.............................31

    2-8-1 Steam Explosion.31

    2-8-2 Ammonia and Carbon Dioxide Explosion.32

    2-8-3 Pre-processing Chemical. 32

    2-8-4 biological pre-treatment. 34

    2-9 Fermentation.............................34

    2-10 Recovery of solids and product. 35

    Chapter three: Test method

    3-1 Materials and liquid used 37.

    2-3 Experiments 37.

    3-3 Design of test method 37.

    1-2-3 effect of concentration 40.

    2-2-3 effect of temperature 40.

    3-2-3 effect of time 41..

    3-4 xylose (XYL) test results.

    3-3-3 effect of time 42.

    3-4 furfural test results (FER).43

    1-4-3 concentration 43.............

    -2-4-3 temperature 43.

    -3-4-3 time 44.

    3-5 results of glucose test (GLU).44

    1-5-3 Concentration 44.

    2-5-3 Temperature 45.

    3-5-3 Time.45.

    Chapter Four: Charts and Tables

    4-1 Modeling the process:.48

    4-2 Examining the conformity of the results obtained from glucose in the proposed models.48

    4-2-1 first model. 54

    4-2-1-1 checking the validity of the model. 54

    Chapter five: conclusion

    Conclusion 56............................

    Suggestions. 57

    References. 58

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Using a surface model to optimize the process of dilute acid hydrolysis of walnut green skin for glucose production