Конструкція, класифікація та принцип дії установок для глибинного культивування організмів

 

 Ministry of Education, Science, Youth and Sports of Ukraine. 
National Aviation University 
Department of biotechnology 
 
 
 
 
 
Coursework 
(Explanatory Note) 
With discipline "Construction Equipment biotech industries" 
 
 
 
Theme: Construction, classification and principle of the submerged liquid fermentors.

 

 

 

Executor: student of 303 group

Institute for Environmental Security

Pasinskaya Katya.

                                                            Supervisor : Kuznetsova O. 
 

 

 

 

 

 

Kyiv 2012

МІНІСТЕРСТВО ОСВІТИ І  НАУКИ, МОЛОДІ ТА СПОРТУ УКРАЇНИ

Національний авіаційний університет

Кафедра біотехнології

 

 

 

 

 

КУРСОВА РОБОТА

(пояснювальна  записка)

З дисципліни «Конструкція обладнання біотехнологічних виробництв»

 

 

 

Тема: Конструкція, класифікація та принцип дії установок для  глибинного культивування організмів

 

 

 

 

 

Виконала студентка 303 групи

Інституту екологічної безпеки

Пашинська  Катерина

Керівник: Кузнєцова О. О.

 

 

 

 

 

Київ 2012

 

NATIONAL AVIATION UNIVERSITY 
INSTITUTE OF ENVIRONMENTAL SAFETY

 

Department of biotechnology 
Discipline: Design of Equipment of Biotechnological Production. 
Specialty: Biotechnology 
Course: Third Group: 303 Semester: Five.

 

OBJECTIVES 
for course work the student

Pashinskaya Katya

 _{(last name, middle student in the genitive case)}

1.TASK for course work of student: Construction, classification and principle of the submerged liquid fermentors.

2. Term of work execution : "1" December 2012 
3. Data given:

 

 4. Content of explanatory note: theoretical part contains a description of the construction of Fermenters ; Selection of Fermenters equipment.

 

 

 

 

 

 

 

 

 

 

НАЦІОНАЛЬНИЙ  АВІАЦІЙНИЙ УНІВЕРСИТЕТ

ІНСТИТУТ ЕКОЛОГІЧНОЇ  БЕЗПЕКИ

 

Кафедра біотехнології

Дисципліна: Конструкція  обладнання біотехнологічних виробництв

Спеціальність: Біотехнологія

Курс: третій Група: 303 Семестр: п’ятий.

 

 

 

 

ЗАВДАННЯ

на курсову  роботу студента

Пашинської Катерини                                

^{(прізвище  ім’я, по батькові студента в родовому відмінку)}

1. Тема роботи: Конструкція, класифікація та принцип дії установок ферментерів глибинного культивування.

 2. Строк здачі студентом закінченої роботи: «1» грудня 2012 р.

3. Вихідні дані до роботи:

 

 

 

4. Зміст розрахунково-пояснювальноїзаписки (перелік питань, які підлягають розробці): теоретична частина вміщує в себе опис ферменторів; вибір ферментерів.

 

 

 

 

 

 

 

5. Defence of the course work:

№ п/п	Name stage	Deadline	Evaluation of the performance
1	Preparation of term paper topics
2	Finding Information
3	Writing the theoretical part
4	Writing Computation part
5	Additions and Changes
6	Protection coursework

 

6. Date of task receiving:

Supervisor of the course work__________ Kuznetsova A.A                                    

Task of execution was taken over by____________ Pashinskaya K.

 

 

 

 

 

 

 

 

 

 

 

 

                               

 

5. Календарний план

№ п/п	Назва етапу	Термін виконання	Відмітка про виконання
1	Отримання теми курсової роботи
2	Пошук інформації
3	Написання теоретичної частини
4	Написання розрахунково-аналітичної  частини
5	Доповнення та редагування
6	Захист курсової роботи

 

6. Дата видачі завдання:

Керівник курсової роботи (проекту) __________  Кузнєцова О.О.

                                                                  ^{(підпис керівника)                        (П.І.Б.)}

Завдання прийняла до виконання ____________ Пашинська К. Л.

                                                                                                     ^{(підпис студента)                        (П.І.Б.)}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ABSTRACT

Explanatory note to the course work 
" Construction, classification and principle of the installations for submerge liquid fermenter.":

The object of research – fermenters process.

Subject of research - fermenters equipment.

The purpose of this work- to examine and analyze the design of Fermenters.

Research methods - analysis, a systematic approach of observation.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

РЕФЕРАТ

 

Пояснювальна записка  до курсової роботи

«Конструкція, класифікація та принцип дії установок для  ферментерів глибинного культивування.

Об’єкт дослідження – процес ферментації.

Мета роботи – дослідити та проаналізувати конструкції ферменторів.

Методи дослідження –  аналіз, систематичний підхід, спостереження.

 

Trickle-bed reactor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Plan

Introduction

1. Types of Fermentation
2. Factors Influencing Fermentations

3. Submerged Fermentations

1. Continuous stirred-tank reactor
1. Impellers for stirred-tank fermenters.
2. Fluidized bed reactor
3. Trickle-bed reactor
4. Bubble-column reactor

Conclusion

References

 

 

 

 

                                                                                                               

 

 

 

 

 

 

 

 

 

 

Introduction

Fermentation processes utilize microorganisms to convert solid or liquid substrates into various products. The substrates used vary widely, any material that supports microbial growth being a potential substrate. Similarly, fermentation-derived products show tremendous variety. Commonly consumed fermented products include bread, cheese, sausage, pickled vegetables, cocoa, beer, wine, citric acid, glutamic acid and soy sauce.

Types of Fermentation

Most commercially useful fermentations may be classified as either solid-state or submerged cultures. In solid-state fermentations, the microorganisms grow on a moist solid with little or no 'free' water, although capillary water may be present. Examples of this type of fermentation are seen in mushroom cultivation, bread-making and the processing of cocoa, and in the manufacture of some traditional foods, e.g. miso (soy paste), sake, soy sauce, tempeh (soybean cake) and gari (cassava), which are now produced in large industrial operations. Submerged fermentations may use a dissolved substrate, e.g. sugar solution, or a solid substrate, suspended in a large amount of water to form a slurry. Submerged fermentations are used for pickling vegetables, producing yoghurt, brewing beer and producing wine and soy sauce.

Solid-state and submerged fermentations may each be subdivided - into oxygen-requiring aerobic processes, and anaerobic processes that must be conducted in the absence of oxygen. Examples of aerobic fermentations include submerged-culture citric acid production by Aspergillus niger and solid-state koji fermentations (used in the production of soy sauce). Fermented meat products such as bologna sausage (polony), dry sausage, pepperoni and salami are produced by solid-state anaerobic fermentations utilizing acid-forming bacteria, particularly Lactobacillus, Pediococcus and Micrococcus species. A submerged- culture anaerobic fermentation occurs in yoghurt- making.

Fermentations may require only a single species of microorganism to effect the desired chemical change. In this case the substrate may be sterilized, to kill unwanted species prior to inoculation with the desired microorganism. However, most food fermentations are non-sterile. Typically fermentations used in food processing require the participation of several microbial species, acting simultaneously and/or sequentially, to give a product with the desired properties, including appearance, aroma, texture and taste. In non-sterile fermentations, the culture environment may be tailored specifically to favour the desired microorganisms. For example, the salt content may be high, the pH may be low, or the water activity may be reduced by additives such as salt or sugar.

Factors Influencing Fermentations

A fermentation is influenced by numerous factors, including temperature, pH, nature and composition of the medium, dissolved 0₂, dissolved C0₂, operational system (e.g. batch, fed-batch, continuous), feeding with precursors, mixing (cycling through varying environments), and shear rates in the fer- menter. Variations in these factors may affect: the rate of fermentation; the product spectrum and yield; the organoleptic properties of the product (appearance, taste, smell and texture); the generation of toxins; nutritional quality; and other physico-chemical properties.

The formulation of the fermentation medium affects the yield, rate and product profile. The medium must provide the necessary amounts of carbon, nitrogen, trace elements and micronutrients (e.g. vitamins). Specific types of carbon and nitrogen sources may be required, and the carbon: nitrogen ratio may have to be controlled. An understanding of fermentation biochemistry is essential for developing a medium with an appropriate formulation. Concentrations of certain nutrients may have to be varied in a specific way during a fermentation to achieve the desired result. Some trace elements may have to be avoided - for example, minute amounts of iron reduce yields in citric acid production by Aspergillus niger. Additional factors, such as cost, availability, and batch-to-batch variability also affect the choice of medium.

 

Submerged Fermentations

 

Industrial fermentations may be carried out either batchwise, as fed-batch operations, or as continuous cultures. Batch and fed-batch operations are quite common, continuous fermentations being relatively rare. For example, continuous brewing is used commercially, but most beer breweries use batch processes.

In batch processing, a batch of culture medium in a fermenter is inoculated with a microorganism (the 'starter culture'). The fermentation proceeds for a certain duration (the 'fermentation time' or 'batch time'), and the product is harvested. Batch fermentations typically extend over 4-5 days, but some traditional food fermentations may last months. In fed- batch fermentations, sterile culture medium is added either continuously or periodically to the inoculated fermentation batch. The volume of the fermenting broth increases with each addition of the medium, and the fermenter is harvested after the batch time.

In continuous fermentations, sterile medium is fed continuously into a fermenter and the fermented product is continuously withdrawn, so the fermentation volume remains unchanged. Typically, continuous fermentations are started as batch cultures and feeding begins after the microbial population has reached a certain concentration. In some continuous fermentations, a small part of the harvested culture may be recycled, to continuously inoculate the sterile feed medium entering the fermenter (Fig. 1(D)). Whether continuous inoculation is necessary depends on the type of mixing in the fermenter. 'Plug flow' fermentation devices (Fig. 1(D)), such as long tubes that do not allow back mixing, must be inoculated continuously. Elements of fluid moving along in a plug flow device behave like tiny batch fermenters. Hence, true batch fermentation processes are relatively easily transformed into continuous operations in plug flow fermenters, especially if pH control and aeration are not required. Continuous cultures are particularly susceptible to microbial contamination, but in some cases the fermentation conditions may be selected (e.g. low pH, high alcohol or salt content) to favour the desired microorganisms compared to potential contaminants.

In a 'well-mixed' continuous fermenter (Fig. 1(C)), the feed rate of the medium should be such that the dilution rate, i.e. the ratio of the volumetric feed rate to the constant culture volume, remains less than the maximum specific growth rate of the microorganism in the particular medium and at the particular fermentation conditions. If the dilution rate exceeds the maximum specific growth rate, the microorganism will be washed out of the fermenter.

Industrial fermentations are mostly batch operations. Typically, a pure starter culture (or seed), maintained under carefully controlled conditions, is used to inoculate sterile Petri dishes or liquid medium in the shake flasks. After sufficient growth, the pre-culture is used to inoculate the 'seed' fermenter. Because industrial fermentations tend to be large (typically 1 JO- ISO m³), the inoculum is built up through several successively larger stages, to 5-10% of the working volume of the production fermenter. A culture in rapid exponential growth is normally used for inoculation. Slower-growing microorganisms require larger inocula, to reduce the total duration of the fermentation. An excessively long fermentation time (or batch time) reduces productivity (amount of product produced per unit time per unit volume of fermenter), and increases costs. Sometimes inoculation spores,

produced as seeds, are blown directly into large fermentation vessels with the ingoing air.

 

Continuous stirred-tank reactor

 

 

 

 

Stirred-tank Fermented is a cylindrical vessel a working height-to-diameter ration of 3-4. A central shaft supports three to four impellers, placed about 1 impeller-diameter apart. Various type of impeller, that direct the flow axially oк radically. Sometimes axial- and radical-flow impellers are used on the same shaft. The vessel is provide with four equally spaced vertical baffles, that extend from near the walls into the vessel. Typically, the baffle width is 8-10% of the vessel diameter.

 

 

 

 

 

CSTR symbol

The continuous stirred-tank reactor (CSTR), also known as vat- or backmix reactor, is a common ideal reactor type in chemical engineering. A CSTR often refers to a model used to estimate the key unit operation variables when using a continuous agitated-tank reactor to reach a specified output. (See Chemical reactors.) The mathematical model works for all fluids: liquids, gases, and slurries.

The behavior of a CSTR is often approximated or modeled by that of a Continuous Ideally Stirred-Tank Reactor (CISTR). All calculations performed with CISTRs assume perfect mixing. In a perfectly mixed reactor, the output composition is identical to composition of the material inside the reactor, which is a function of residence time and rate of reaction. If the residence time is 5-10 times the mixing time, this approximation is valid for engineering purposes. The CISTR model is often used to simplify engineering calculations and can be used to describe research reactors. In practice it can only be approached, in particular in industrial size reactors.

Assume:

• perfect or ideal mixing, as stated above

Integral mass balance on number of moles N_i of species i in a reactor of volume V.

1.

 

Cross-sectional diagram of Continuous stirred-tank reactor

where F_io is the molar flow rate inlet of species i, F_i the molar flow rate outlet, and stoichiometric coefficient. The reaction rate, r, is generally dependent on the reactant concentration and the rate constant (k). The rate constant can be determined by using a known empirical reaction rates that is adjusted for temperature using the Arrhenius temperature dependence. Generally, as the temperature increases so does the rate at which the reaction occurs. Residence time, , is the average amount of time a discrete quantity of reagent spends inside the tank.

Assume:

• constant density (valid for most liquids; valid for gases only if there is no net change in the number of moles or drastic temperature change)
• isothermal conditions, or constant temperature (k is constant)
• steady state
• single, irreversible reaction (ν_A = -1)
• first-order reaction (r = kC_A)