CHE505 Reaction Engineering 2 - Assignment 2 (My Answer) PDF

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1 EH/MAC-JUNE 2021/CHE505 UNIVERSITI TEKNOLOGI MARA ASSIGNMENT 2 COURSE : REACTION ENGINEERING II COURSE CODE : CHE505 SUBMISSION DATE : 25 JULY 2021 INSTRUCTIONS TO CANDIDATES 1. This assignment consists of one (1) question. 2. Drawing and calculations must be shown clearly. All references must be ...

Description

1

EH/MAC-JUNE 2021/CHE505

UNIVERSITI TEKNOLOGI MARA ASSIGNMENT 2

COURSE

:

REACTION ENGINEERING II

COURSE CODE

:

CHE505

SUBMISSION DATE

:

25 JULY 2021

INSTRUCTIONS TO CANDIDATES 1.

This assignment consists of one (1) question.

2.

Drawing and calculations must be shown clearly. All references must be listed.

IMPORTANT NOTES: 1. This is a group assignment (3 members in a group). 2. Plagiarism is not allowed. PENALTY will be given to those involved. 3. Answer all questions and submit before/on the date mentioned. 4. Use the following file name for the assignment submission: NAME_ID_EH2205GROUP_ASSGN2 (example: SharmeeMatali_2015671274_EH2205C_ASSGN2) List the name of the group members and student ID on the front cover of the assignment. 5. The answers should be submitted in a pdf file to the assignment folder instructed by your lecturer. 6. Late submission will not be entertained and considered as no submission.

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EH/MAC-JUNE 2021/CHE505

QUESTION (PO2, CO2, CO3, C4, C5) Hydrogen peroxide (H2O2) is a mild antiseptic used on the skin to prevent infection of minor cuts, scrapes, and burns. Hydrogen peroxide is also known as a potential “green” cleaning agent that can avoid the formation of halogenated by-products. It may also be used as a mouth rinse to help remove mucus or to relieve minor mouth irritation. This product works by releasing oxygen when it is applied to the affected area. The release of oxygen causes foaming, which helps to remove dead skin and clean the area. Hydrogen peroxide can also be used occasionally at higher concentrations for maintenance cleaning purposes of fouled heat exchangers, cooling water loops, and process water loops. Performing an occasional shock cleaning of a heat exchanger with hydrogen peroxide can remove buildup from surfaces and can result in improved heat transfer efficiency. By removing surface fouling, hydrogen peroxide may also improve the efficiency of other biocides such as bleach, bromine, and non-oxidizers. You are working as a Research Engineer in one of Malaysian-based global company. Recently, your company has decided to expand its operation to mitigate the fouling problem of the pipeline in the renewable energy, and oil and gas industry by using the biochemical process. The plan is to produce hydrogen peroxide from microorganisms, preferably from seawater. Your team has been assigned to this project which required you to propose a suitable biocatalytic process in obtaining hydrogen peroxide via. fermentation process. Using your background study in biochemical reaction engineering, prepare a detailed technical report which includes: a) Process Background i) The target amount of production. ii) Selection of substrate to be used in the synthesis and justifications. iii) Selection of microbes used and justifications. iv) Explanations on the product synthesis and fermentation process. b) Biochemical Reaction i) Explanations on the reaction occur in the process to produce the product. ii) Relationship between product formation, substrate consumption, and cell growth. iii) All related balanced stoichiometric equations, reaction mechanism, and rate law with reference and direction of the reaction. iv) Kinetic parameters of the enzymatic and fermentation process (biocatalytic reaction). v) Yield coefficient related to process. vi) Mass transfer occurs in the process (if it is an aerobic fermentation).

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EH/MAC-JUNE 2021/CHE505

c) Bioreactor Design i) The suggestion of an appropriate bioreactor to be used and devices to be installed. ii) Justifications and assumptions of selected bioreactor. iii) The reactor design (volume, height, diameter, impeller, and the residence time based on the compositions when the reaction has gone to completion).  Schematic diagram of selected bioreactor and dimensions.  Clear calculation basis and details on the information required for calculation.  Clear and complete statements of valid assumptions used in the calculations.  Appropriate units for the calculations performed. iv) Reaction conversion for all limiting cases that might be happening during the process. d) Mitigation of Fouling i) The suggestion of an appropriate method to mitigate fouling in the pipeline using the product produced. ii) Explanations on the product reaction to mitigate fouling. iii) Provide all related balanced stoichiometric equations and the reaction mechanisms of fouling and mitigation with reference and direction of the reaction. Proper references and citations are required in this report. Hand over your proposal to the Operation Manager in a well-organized technical report. There will a meeting on 26th July 2021. Therefore, you need to submit the report by 25th July 2021 (11.59 p.m). Failure to submit the report on time will affect your salary and annual performance.

ALL THE BEST!

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CHE505 REACTION ENGINEERING II

ASSIGNMENT 2 BIOREACTOR ENGINEERING

Lecturer MIRADATUL NAJWA

Team Members Arif Hanafi Bin Md Zaki Nellisa Shariza Binti Awang Ramli Muhamad Azrin Bin Mohamad Yamin

2020983171 2020970415 2020975413

Table of Contents 1.

2.

3.

PROCESS BACKGROUND .......................................................................................................... 4 1.1.

Target Amount of Production ................................................................................................. 4

1.2.

Selection of Substrate.............................................................................................................. 5

1.3.

Microbes used ......................................................................................................................... 6

1.4.

Product Synthesis .................................................................................................................... 7

BIOCHEMICAL REACTION ........................................................................................................ 8 2.1.

Reaction occur in the process to produce the product ............................................................. 8

2.2.

Relationship between product formation, substrate consumption and cell growth ................. 9

2.3.

Stoichiometric Equation, Reaction Mechanism, Rate Law and Direct of reaction ............... 11

2.4.

Kinetic Parameter of enzymatic and fermentation process (biocatalytic reaction) ............... 14

2.5.

Yield coefficient related to the process ................................................................................. 17

BIOREACTOR DESIGN ............................................................................................................. 18 3.1

Type of Bioreactors ............................................................................................................... 18

3.1.1

Batch bioreactor (batch culture) .................................................................................... 18

3.1.2

Fed-Batch bioreactor (continuous culture).................................................................... 19

3.1.3

Continuous bioreactor (continuous culture) .................................................................. 19

3.2

Bioreactor selection............................................................................................................... 21

3.3

Design of Bioreactor ............................................................................................................. 22

3.3.1

Determination of reactor volume .................................................................................. 23

3.3.2

Determination of Impeller Dimension .......................................................................... 25

3.4

Reactor Schematic Diagram.................................................................................................. 26

3.5

Reaction Conversion ............................................................................................................. 27

4.

FOULING MITIGATION ............................................................................................................ 28 4.1.

5.

Mitigation of Fouling ............................................................................................................ 28

REFERENCES ............................................................................................................................. 32

1. PROCESS BACKGROUND 1.1. Target Amount of Production Hydrogen Peroxide (H2O2), is a colourless liquid chemical state in room temperature that has widely used for cleaning in personal care products such as in toothpaste, bleaches and mouthwash, bathroom cleaners and laundry stain removers (About Chemical Safety Facts, 2019). In addition, H2O2 at high concentration is use for cleaning fouled heat exchangers. Fouling in heat exchanger usually caused by the deposition and accumulation of unwanted material where the fluid that deposited onto the inner tube/shell wall of heat exchanger. This will further cause thermal resistance which is capable of decreasing process efficiency (Understanding and preventing heat exchanger fouling, 2019). Aquaculture having intensive activity becoming the source of infectious diseases which causing significant stock losses and problems to marine creature (Cynthia S. et al, 2014 – sequeros). Biohydrogen is the hydrogen produced by bio process which commonly produced by algae, bacteria and archaea. Microalgae is used as the microbes for fermentation to produce Hydrogen, H2. This process is used to produce the next step as a feedstock to react with Oxygen to produced Hydrogen Peroxide, H2O2. Our target for this experiment is to produced Hydrogen Peroxide, H2O2 from biohydrogen.

1.2. Selection of Substrate Substrate is a medium for a substance to grow. Chemical component of a reaction operated on the material is transformed into a new product and change the final composition in the end of the reaction (Toppr-guides, 2020). Several types of substrates is available and varies according to the type of the reaction. Milling, ultrasonic, microwave, steam explosion, chemical oxidation, and enzymatic hydrolysis are the most popular methods for pre-treatment of microalgae to improve carbohydrates hydrolysis. This is to disrupt the cell wall to release the organic substances from the cells which is then to produce the biohydrogen production. Also, the purpose is to enhance the conversion process (Wang & Yin, 2018). Here, we are discussing about the pre-treatment micro-algae of using chemical and physical method. Scenedesmus obliquus are investigated for fermentative process producing Hydrogen using biomass as the feedstock. It is a unicellular green alga which can generate molecular hydrogen in the presence of light. Anaerobic alteration is required to activate the relevant enzyme hydrogenase. The mechanism of hydrogen generation is described, as well as its connection to the photo synthetic electron transport chain (Scenedesmus Obliquus - an overview | ScienceDirect Topics, 2011). It is expected to have the Scenedesmus obliquus as the substrate with the inoculum of Clostridium Butyricum DSM with initial concentration of 50g/L (Wang & Yin, 2018).

1.3. Microbes used Microalgae are unicellular photosynthetic microorganisms which can be found in seawater or freshwater. The microorganism is characterized by a short generation time and multiplying exponentially under desirable environmental conditions (Microalgae - an overview | ScienceDirect Topics, 2011). This can be differed in few different ways as they grow in 3 different ways such as; autotrophy, heterotrophy and mixotrophy as the carbon source and sunlight is the main energy source. Microalgae have potentially attracted as worldwide microbes as it is extensively has likely in the renewable energy, biopharmaceutical and nutraceutical industries (Khan et al., 2018). This Microalgae has a different component according to their source and cultivation environment species. Generally, it chemical composition is mainly composed of Proteins (4060%), Carbohydrates (20-30%) and Lipids (10-20%). The main function of microalgae structures is energy conversion, and their simple growth allows them to acclimate to changing environmental conditions. Microalgae are a relatively new energy source when related to cellulose-based biomass and waste activated sludge produced by wastewater treatment plants. They also have many advantages, including a rapid growth rate due to CO2 complex, the ability to combine microalgae culture with wastewater treatment and help the environment, also the ability to be utilised as a substrate due to their high Carbohydrate content and simple structure.

1.4. Product Synthesis Hydrogen Peroxide is the final product target for this experiment. The Hydrogen produced from the microalgae as the feedstock is being react with Oxygen to produce Hydrogen Peroxide, H2O2. Hydrogen production from physically and chemically pre-treated microalgae is expected to increase the yield of Hydrogen compared to the non-treated. Microalgae may produce large amounts of carbohydrates as reserve materials, such as starch or cellulose, which are suitable feedstocks for hydrogen generation. Also, it has the potential to be used to produce biohydrogen in a cost-effective and ecologically friendly way. Biohydrogen generation from microalgae can be combined with CO2 mitigation, wastewater treatment, and the manufacture of high-value compounds. The microalgae as the feedstock to biohydrogen production has several benefits such as to the environment where the microalgae production does not necessitate the use of herbicides or pesticides. When they're utilised to make biofuels, therefore, Nitrous Oxide emissions might be reduced. Microalgae do not require arable land to grow and instead grow in aqueous medium, so, they may not require land-use change, reducing environmental consequences, and their production uses less water. It is assumed to have product of biohydrogen with yield of 113.1 mL/g. Reactor was design to get the production target where the final calculation is the diameter of reactor is 2.241m with height of 2.802m equip with Ruston Turbine impeller of 0.740m diameter.

2. BIOCHEMICAL REACTION 2.1. Reaction occur in the process to produce the product In this project, the microalgae derived from seawater is used to produce biohydrogen. After that, the biohydrogen that produced from the microalgae fermentation process is then reacted with oxygen to produced hydrogen peroxide. There will be two stage of reaction that occurs in the production of hydrogen peroxide. The main reaction is the photofermentation of glucose to produce biohydrogen from microalgae which specifically taken from seawater. Photofermentative hydrogen production is a bioprocess in which photosynthetic bacteria fermented with glucose or organic acids like acetic acid, lactic and butyric acid which produced from the dark fermentation to produce biohydrogen in the presence high intensity light such as sunlight under the anaerobic condition (Energy, 2015). Below is the reaction involving photo-fermentation of microalge bacteria; HV

C6H12O2+4H2O → 8H2+4CO2

The last stage with the production of hydrogen peroxide. The biohydrogen produced in the earlier reaction is then reacted with O2 to produce hydrogen peroxide, H2O2. Below is the chemical reaction for the process: H2+O2→H2O2

2.2. Relationship between product formation, substrate consumption and cell growth The kinetic model of cell growth is capable of predicting product formation to a large extent. Cell growth is defined as cell having an increase in its mass and physical size, biological and chemical surroundings. Cell growth and cell division are inseparable for microbes as bacteria divides by binary fission, yeast cells by budding and viruses divide intercellularly (J. D. Wang & Levin, 2009). Mathematical models provide strategy for solving problems encountered in fermentation process. A kinetic model that describes microbial growth, product formation and substrate consumption and experimental data were fitted with modified logistic equation (Sakthiselvan et al., 2020). Beforehand, the cell growth indicates type pf phases occurred during the cultivation of cells which consist of lag phase, exponential phase or log phase, stationary phase, and death phase. These phases sum up the journey of the cell growth from newborn to its end.

Figure 1-Typical Growth Curve for a Bacteria Population

During the fermentation, cell growth is the fundamental response followed by the product formation. There are three types of growth curves which clarify the relationship between product formation and cell growth. Firstly, growth associated where growth linked products by growing cells and hence, primary metabolites. Figure 2 shows the product is simultaneously formed with the growth of cells.

Figure 2- Growth Associated

Next, non-growth associated curve where they are formed by cells which are not metabolically active and hence, are called metabolites. Figure 3 shows that product formation is unrelated to growth rate but is a function of cell concentration. The rate of microbial growth is calculated as follows:

Rearranging the equation yield the equation below:

The expression rate for product formation is:

Where; qp =the rate of formation of product.

2.3. Stoichiometric Equation, Reaction Mechanism, Rate Law and Direct of reaction Reaction condition i.

Anaerobic condition- oxygen are not required during the photofermentation process

ii.

Irreversible reaction- reaction that occur during the photofermentation and production hydrogen peroxide are irreversible. All of the products that produce can’t be change to the reactant

iii.

Sunlight- required energy sources during the photofermentation process

Stoichiometric Equation HV

C6H12O2+4H2O → 8H2+4CO2 Table 1-Stoichiometry Table Species C6H12O2

Symbol A

Initial FAo

Remaining -FAo

H2

B

FAoϴB

8FAoX

CO2

C

FAoϴC

4FAoX

Concentration 𝐶𝐴 1−𝑋 = 𝐶𝐴𝑜 ( ) 1 + 𝜀𝑋 𝐶𝐵 𝜃𝐵 + 8𝑋 = 𝐶𝐴𝑜 ( ) 1 + 𝜀𝑋 𝐶𝐶 𝜃𝐶 + 4𝑋 = 𝐶𝐴𝑜 ( ) 1 + 𝜀𝑋

Since ϴB=ϴC=0, the concentration of the product are also equal (CB=CC) Glucose, C6H12O6 Mass of glucose, C6H12O6

= 6(12) + 12(1) + 6(16) = 180 g = 0.18 kg

Density of glucose

= 1560 kg/m3

Volume of glucose

=

𝑀𝑎𝑠𝑠 𝑜𝑓 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑔𝑙𝑢𝑐𝑜𝑠𝑒

=

0.18 𝑘𝑔 1560 𝑘𝑔/𝑚3

= 1.1538 × 10−4 𝑚3

Carbon Dioxide, CO2 Mass of carbon dioxide, CO2 = 1(12) + 2(16) = 44 g = 0.044 kg Density of carbon dioxide

= 1.98 kg/m3

Volume of carbon dioxide

=

𝑀𝑎𝑠𝑠 𝑜𝑓 𝑐𝑎𝑟𝑏𝑜𝑛 𝑑𝑖𝑜𝑥𝑖𝑑𝑒 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑐𝑎𝑟𝑏𝑜𝑛 𝑑𝑖𝑜𝑥𝑖𝑑𝑒

=

0.044 𝑘𝑔 1.98 𝑘𝑔/𝑚3

= 0.0222 𝑚3

Hydrogen, H2 Mass of hydrogen, H2

= 2(1) = 2 g = 0.002 g