International University - Vietnam National University
School of Chemical and Environmental Engineering
COURSE: INDUSTRIAL CHEMISTRY_S1_2022-23_G01
INSTRUCTOR: Dr. Phùng Thanh Khoa - Dr. Vũ Bảo Khánh.
GROUP 01:
● Lê Huỳnh Minh Anh - BTCEIU20010
● Nguyễn Quang Khang - BTCEIU20034
● Lê Quỳnh Phương Thảo - BTCEIU20039
● Nguyễn Đoàn Minh Tú - BTCEIU20083
DUE DATE: 04/12/2022.
PROJECT: INDUSTRIAL PROCESS OF ASCORBIC ACID
I.
INTRODUCTION
Ascorbic acid - a common substance that exists crucial in the food and cosmetic industry is
introduced. 4 aspects of it will follow up the outline. The mechanism and lab-scale synthesis
won’t be mentioned. Instead, the industrial scale and the way to optimize reaction for
building up plants are what we considered. First, for the process and technology, we will
focus on the process that is most optimized and widely applied - 2 step fermentation. Then,
some aspects that require consideration in plant construct to gain profit will be introduced.
Finally, what vitamin C serves for our life are brought in to gain the whole view of this
substance.
II.
PROCESS AND TECHNOLOGY
Materials and Methods:
D-sorbitol, which can be used as a sugar substitute, is also commonly applied in the industrial
manufacturing of food, humectant, dietary supplement and ascorbic acid. Therefore, ascorbic
acid is generally produced from D-sorbitol. Compared to other feedstocks such as corn,
wheat, molasses; the current price for sorbitol is approximately 500 USD per tonne, while
corn is 146 USD per tonne, wheat is 232 USD per tonne, molasses is 261 USD per tonne.
Besides, glucose extraction from corn, molasses and wheat is required before the conversion
of glucose into D-sorbitol, which is called “Pre-treatment”.
Process technology selections:
In fact, the Reichstein process, the two-step fermentation with a single culture, and the
two-step fermentation with mixed culture are three available process technologies used to
produce ascorbic acid. The similar overall yield of production is 60%. Nevertheless, the
two-step fermentation seem to be economical and eco friendly than the Reichstein process.
The chemical equation for the Reichstein process:
Figure 1: Details for reaction from D-glucose into L-ascorbic acid
C6H14O6 + 1/2 O2 + NaHCO3 → C6H8O6 + NaOH + CO2 + 2H2 + H2O
(Sorbitol + Oxygen + Sodium bicarbonate → Sorbose + Sodium hydroxide + Carbon dioxide
+ Hydrogen + Water)
-
This is considered the first industrial process of ascorbic acid through five chemical
reactions and one biochemical reaction and has been applied for 60 years before the
2nd fermentation step exist.
Comparison of Two-step and Reichstein? Why is the first one preferred?
3 Kinds: Reichstein process, the two-step fermentation with a single culture, and the two-step
fermentation with a mixed culture.
-
Reichstein: Higher conversion efficiency
-
Two-step fermentation:
+ Production cost is 2-third of Reichstein, involves lesser steps, reduces energy
and water consumptions, operates at milder, cheaper, safer conditions;
environmentally friendly.
+ Reduce the use of solvent → Harmful, toxic.
Small comparison of single and mixed culture of 2 step fermentation
Single culture only uses one bacterium, whereas the mixed culture uses two different
bacteria; Mixed: fermentation step is manipulated harder; Difficult to obtain an optimum
balance among the microorganisms involved, and the cultivation of two different bacteria
requires more time and space, more complicated than the previous culture, unable to take
over the contamination
Two-step fermentation process with single culture:
The chemical equation for the two-step fermentation process:
(For a single culture and a mixed culture)
C6H14O6 + 3/2 O2 + Na2CO3 + NaHCO3 → C6H8O6 + 3 NaOH + 2 CO2 + 2 H2O
(Sorbitol + Oxygen + Sodium carbonate + Sodium bicarbonate → Sorbose + Sodium
hydroxide + Carbon dioxide + Water)
Table 1: Thermodynamics and chemistry data for equipment
Figure 2: Two Pathways - Classical 2 fermentation step and Novel one
Figure 3. Overview of Ascorbic acid manufacturing pathway of 2 step fermentation
-
1st Fermenter: Conversion of sorbitol to sorbose
+ 200g/L Sorbitol solution (70%) + ammonia, water, air undergo oxidative
fermentation under 30 °C and pH 6 to First fermenter.
+ Sorbitol is converted to sorbose by Gluconobacter oxydans, 98% conversion.
+ Before entering the second fermenter, the biomass produced in the first fermenter is
being removed by passing the fermentation broth through a microfilter. The
fermentation Broth is fermented in the 2nd fermenter by Pseudoglyconobacter
Saccharoketogenes for 72 h to produce sodium keto-gluconic acid.
-
2nd
Fermenter:
Conversion
of
sorbose
to sodium
keto-gluconic acid
by
Pseudoglyconobacter Saccharoketogenes:
+ Slurry from the fermenter is then transferred to a microfilter (MF-101) to separate
biomass. ~1% sol. loss.
-
Recovery of 2-keto-gluconic acid from sodium keto-gluconic acid:
+ By bipolar membrane electrodialysis (GBX-101) through the exchanges of cation
and anion with water molecules.
+ The recovered 2-keto-glconic acid is fed to an evaporator (TFE-101) to remove the
water before entering a continuous stirred tank reactor => increase product in
R-101. In the CSTR (R-101), 2-keto -gluconic acid undergoes an esterification
process with methanol at 64 °C to produce methyl gluconate [17].
+ Reaction
between
methyl
gluconate with sodium carbonate in R-102:
2-keto-gulonic acid is cooled to 30 °C by a cooler (HX-103), product formed:
sodium ascorbate → Another bipolar membrane electrodialysis (GBX-102) to
recover ascorbic acid. The water produced in the reactor is evaporated in a vacuum
evaporator (TFE-102) before feeding the ascorbic acid to crystallization process
(CR-101) for 54 h at 4 °C. Solid ascorbic acid is then freeze-dried to −35 °C after
filtration (NFD-101) process due to the heat sensitivity properties of a solid
ascorbic acid. Since the optimum storage temperature for solid ascorbic acid is 4
°C, it is heated before feeding into a storage tank.
Process optimized and heat integration:
-
Optimized by recycling sorbose back to the second fermenter. As it contains more
sorbose than sorbitol → Affects the conversion of sorbitol to sorbose if it is recycled
back to the first fermenter. This was done to minimize waste and to increase
production. Production of ascorbic acid has increased by 24% after optimization.
Purity: of the base case is 99.3%, whereas the purity of the recycled process is 99.2%.
-
Heat integration was performed to minimize the consumption of energy and total
operating cost
-
The plant-wide control philosophy: Top-down control which means we identify the
process variables, control degrees of freedom, control structure, and options for
decomposition. Then establish the overall control structure (in conceptual form)
Control objectives for the plant:
1. To achieve production capacity of 500 tonne per year
2. To control of reactant ratio to minimize waste and increase reaction conversion
3. To control of microenvironment for bacterial fermentation as the performance of bacteria is
strongly dependent on the microenvironment
4. To achieve product specification of 95% purity
5. To maximize heat exchange between process stream to minimize energy consumption
6. To control of optimum operating conditions
7. To ensure safe operation
III.
COMMERCIAL USE
The main use of ascorbic acid is as an antioxidant. In terms of health, it supports quick
wound healing or improves flu. In terms of skin tone, it aids in skin lightening and even skin
tone. To take advantage of that, the researchers created commercial value for this active
ingredient by manufacturing products that contain the ingredient vitamin C.
Cosmetic
The forms of acid ascorbic in cosmetics are commonly used and most of them work well on
the skin, including the following active ingredients:
● L-ascorbic acid: This active ingredient has the ability to affect the dermis layer of
the skin and is the closest form to the natural form of Vitamin C in the skin. When
added to cosmetics at a pH less than 4 (from 2.6 to 3.2) and used at a rate of 5% or
more, skin problems such as dark spots, uneven skin tone are resolved and
supported. skin becomes bright. L-ascorbic Acid helps fortify the natural skin
barrier by neutralizing free radicals from the environment, minimizing negative
effects on the skin.
● Ascorbyl Palmitate: It is an oil-soluble Vitamin C derivative that does not cause
irritation to the skin. It has a positive effect on inflammation levels and plays a role
in energy generation, protein transformation and the formation of membrane
phospholipids.
● Ascorbyl Glucoside: Because of its hydrating properties, this ingredient is safer for
the skin because it is just a derivative of Vitamin C instead of pure Vitamin C,
especially suitable for sensitive skin areas such as the skin around the eyes.
Vitamin C is found in serums, cleansers or creams and many other cosmetics. But serums and
creams containing Vitamin C ingredients are always best-selling because it really works on
the skin. Example:
Health and Nutrition
Vitamin C is most commonly used and most commonly through supplements, usually in
powder or tablet form. It is used to protect cells, maintain healthy skin and increase recovery
time from colds, flu and other similar illnesses. Especially on days with erratic weather,
people often catch colds, so people are more conscious of their health and more affordable
and readily available solutions, the use of supplements, etc. Vitamin C supplementation has
greatly increased. Research carried out by the Health Food Manufacturers Association in
2016 found that around 27% of Britons take vitamin C regularly.
Ex: This is an illustration of some oral vitamin C commercially available. These products
always gain a certain amount of purchase, especially during the covid pandemic. Vitamin C
became one of the products to prevent this epidemic from becoming serious.
Water treatment
Chlorine is used in water treatment facilities to eradicate microbes from the water supply. It is
an effective bacteria neutralizer and makes the water safe to drink, the chlorine solution
released after water treatment can contaminate streams and affect aquatic life. It is an
effective bacteria neutralizer and makes the water safe to drink, the chlorine solution released
after water treatment can contaminate streams and affect aquatic life. Leaving water in an
open container and waiting for air and sunlight to naturally dissolve the chlorine over time is
one of the 'passive' methods of dechlorination. In large scale operation, this method is not
suitable to use because it is time consuming and not feasible. So ascorbic acid is an effective
chemical method for chlorine neutralization that is being used more and more often,
effectively and much safer than other chemical dechlorination methods through the use of
chemicals. sulfur-based. Because of this, the addition of ascorbic acid and sodium ascorbate
to chlorinated water renders it environmentally safe enough to be used.
IV.
ECONOMIC
3 Parts that need to be set up before building a plant: Cost estimation, Production cost and
Profit.
Cost estimation (definition): Cost estimation in project management is the process of
forecasting the financial and other resources needed to complete a project within a defined
scope. Cost estimation accounts for each element required for the project—from materials
to labor—and calculates a total amount that determines a project’s budget (1).
Cost production: Include direct cost, indirect cost, and FCI (Fixed Capital Investment).
+ Direct cost includes cost of purchased equipment and transportation charges [USD
126.77 million].
+ Indirect costs include the expenses [USD 12.43 million].
+ FCI is the total summation of direct and indirect cost.
+ As for the working capital, it is approximately 15% of the Total Capital Investment
(TCI). [USD 7.78 million]
+ TCI is obtained by adding the FCI and working capital.
[[Direct cost + Indirect cost + FCI + Working capital + TCI - example Table 2]]
Table 2: Lang factors for approximation for capital investment
+ POC - Plant Overhead Cost = cost ( raw materials + operating labor + utilities +
operating supervision + maintenance + repair + operating supplies + laboratory
charges + royalties)
+ TMC - Total Manufacturing Cost includes taxes for the property, insurance, financing
and depreciation cost
+ TPC - Total Production Cost is the summation of POC, TMC and total general
expenses (TPC = POC + TMC + TGE) [USD 43.56 million]
[[POC, TMC, and TPC - example Table 3]]
Table 3: Estimation of operating costs
Economic analysis & Profitability analysis & Sensitivity analysis
According to the data of total investment,, total capital, and total operating costs, we will
have three scenarios: base case, best case, and worst case. These cases are compared, and
then the most feasible case is chosen.
+ The best case indicates a 20% increase of the product selling price, 20% decrease of
the raw material cost, and 20% decrease of tax rate.
+ The worst case is when the product selling price decreases by 20%, the raw material
cost increases by 20%, and the tax rate also increases by 20%.
[[The profitability analysis for these three different cases is generated and shown in Table 4.
The cumulative cash flow diagram for these three cases was shown in Fig. 6.]]
Table 4: Profitability analysis for base case, best case and worst case
Figure 6: Cumulative cash flow diagram for base, best and worst case
→ From the data in Tab. 4 and Fig. 6, we have the payback period, return of investment, and
net profit of each case and compare them.
V.
CONCLUSION
In summary, based on popularity in industries and cosmetics, ascorbic acid is increasingly
widely used and produced on a large scale. Therefore, we decided to choose the 2-step
fermentation process because of its advantages in terms of time and cost. At the same time,
the problem of construction and production costs in order to make a profit is carefully
considered in each case. From those factors, a perfect plan will be set up and operated for a
long time.
VI.
REFERENCE
1. A-63 Appendix G Plantwide Control System Design G.1 PROCEDURES FOR THE
DESIGN OF PLANTWIDE CONTROL SYSTEMS. (n.d.). Retrieved November 26,
2022, from Plantwide Control System Design
2. Lim, S. M., Lau, M. S. L., Tiong, E. I. J., Goon, M. M., Lau, R. J. C., Yeo, W. S., Lau,
S. Y., & Mubarak, N. M. (2020). Process design and economic studies of two-step
fermentation for production of ascorbic acid. SN Applied Sciences, 2(5). Process
design and economic studies of two-step fermentation for production of ascorbic acid
| SpringerLink
VII.
WORKLOAD DIVISION
Team members
Task
Nguyễn Quang Khang - BTCEIU20034
Present + Edit clip + Record + Slide
prepare
Lê Huỳnh Minh Anh - BTCEIU20010
Present + Content + Slide prepare
Nguyễn Đoàn Minh Tú - BTCEIU20083
Present + Content + Slide prepare
Lê Quỳnh Phương Thảo BTCEIU20039
Present + Edit clip + Slide prepare