FACULTY OF ENGINEERING AND BUILT ENVIRONMENT

DEPARTMENT OF CHEMICAL AND PROCESS ENGINEERING

KKKB2424, KKKR2034, KKKR2324, KKKR2364

BIOCHEMICAL ENGINEERING PROGRAM

REPORT TITLE:

PRODUCTION OF CITRIC ACID

KKKB2424: PROF DR JAMALIAH MD JAHIM

KKKR2034: PROF DR MEOR ZAINAH & DR MASLI IRWAN ROSLI

KKKR2324: PROF IR DR MASTURAH MARKOM & DR DARMAN NORDIN

KKKR2364: DR MOHD SHAHBUDIN MASDAR

GROUP 3

GROUP MEMBERS

NAME MATRIC NO.

MUHAMMAD KHAIRIL AZIM BIN ABDULLAH A133275

SONIA DILIP PATEL A133115

WONG MEI FANG A132213

ZURAIFAH BINTI MINHAT A132221

INTRODUCTION

• Citric acid– Citric acid is a week organic acid found in citrus fruits

– Molecular formula is C6H8O7 and belongs to the carboxylic acids groups

– Stronger acid compared to other typical carboxylic acid.Produced by fermentation and suitable pH is around 3-6

• Application In Industry– Beverages

– Food

– Pharmaceutical

– Agriculture

– Metal Industry Structural Formula of Citric Acid

SOURCE OF RAW MATERIALS

Beet Molasses• the source of sugar for microbial

production of citric acid

• low cost and high sugar content

• low content of trace metals

• acts as carbon source of the fermentation

Microorganism• mycomycetes of A.niger species

can produce high yield

• consequence of incomplete respiration

Aspergillus Niger• filamentous ascomycete fungus

• maintained at pH 4.5 and temperature at 5 °C

• The best strain for citric acid production

• Scientific classification of A.niger

Domain Eucaryotes

Kingdom Fungi

Phylum Ascomycota

Subphylum Pezizomycotina

Class Eurotiomycetes

Order Eurotiales

Family Trichocomaceae

Genus Aspergillus

Species A.Niger

DEMAND AND SUPPLY

• The high demand in citric acid is the wide usage as acidulent in food and beverage industry.

• In the 1980s, U.S.A has been the leading country in producing citric acid. But, in the year of 1995, the Chinese production volume of citric acid has surpasses that of United States (Connor 2008) due to the lower cost of raw materials and the lower price of citric acid.

• In the year of 2007, worldwide annual production was approximately 1.7 million metric tons. According to Carlos (2006), the production rate of citric acid has growth of 3.5 to 4.0% per year.

0

0.5

1

1.5

2

2.5

3

3.5

2007 2008 2009 2010 2011 2012

me

tric

to

nn

es

(mill

ion

)

Year

Global Citric Acid Demand and Supply Graph

Demand

Production

PROCESS DESCRIPTION

1. Inoculation of Aspergillus Niger

2. Fermentation of Citric Acid

3. Biomass Removal

4. Liquid-liquid extraction

5. Crystallization

6. Drying

STOICHIOMETRY EQUATIONS

• Given the yield of product with respect to substrate, YP/S =

0.77, the stoichiometry coefficients is solved.

MATERIAL BALANCE

Ci

(gL-1)

Co

( gL-1)

Ni

( molh-1)

No

( molh-1)

Fi

(kgh-1)

Fo

(kgh-1)

Sucrose 20.0 2.157 128.5 13.78 43.95 4.71

Ammonia 0.5 0.0745 64.31 9.58 1.23 0.16

Biomass 0 3.670 0 322.046 0 8.020

Product 0 13.740 0 156.36 0 30.02

Water 0 3.570 0 433.36 0 7.80

Oxygen 3 281.25 2 947.44 105 94.32

Carbon dioxide 0 108.09 0 4.76

Nitrogen 12 343.75 12 343.75 345.63 345.63

Σ Fi

= 501.45

Σ Fo

= 501.422

ENERGY BALANCE

Hi ( Jmol-1) Ho( Jmol-1)

Sucrose 1073.55 1789.25

Ammonia 240.27 401.61

Biomass 0 63.4655

Product 0 1415

Water 0 304.82

Oxygen 88.42 197.3918

Carbon dioxide 0 764.36

Ei = Σ Nik∆Hik= 443,531.06 J/hr Ei = Σ Nok∆Hok= 166,708.454 J/hr

Q = EOUT – EIN + rΔHbr = 166 708.454 - 443 531.06 + - 153 552.6(0.0015)= -277 052.934

Mass flow rate of cooling water :

Q = mCp (T2 – T1)

m = 13256kg/hr

BIOREACTOR

• Catalyst

– A small quantities of iron and limited amount of zinc

– Copper

• By Product

– Biomass

– Gluconic acid

– Oxalic acid

H=10.06m

D = 5.03m

Advantages1. Flexible and adaptable2. Wide range of mixing intensity3. Ability to handle high viscosity

media

• Typical Batch Growth Curve

0

5

10

15

20

Su

bstr

ate

, B

iom

ass a

nd

Pro

du

ct

co

nce

ntr

ati

on

(g

/l)

Dilution Rate (h-1)

A Graph of Substrate, Biomass and Product over Dilution Rate

S(g/l)

X(g/l)

P (g/l)

HEAT TRANSFER

• Heat can be transferred through– Convection

– Conduction

– Radiation

• Factors influencing Heat Transfer– Temperature diffence– Fluid flow rate– Nature of conducting materials– Surface area and length

• Glass wool which act as a cooling jacket of fermenter.

• q = 632.94 W

MASS TRANSFER

• Fick’s Law of diffusion:

• Wilke-Chang correlation:

• Factors influencing mass transfer

– Concentration gradient

– Temperature

– Phase

– Molecular distance

– Surface area

– length

SEPARATION

• Rotary filter

– To filter off mycelium(biomass)

• Sieve tray column

– Liquid-liquid extraction

– Alkyl amide as extractant

– Water as solvent in stripping

• Rotary filter

• Sieve Tray Column

DESIGN OF SIEVE TRAY COLUMN

• Smin / F = (XA)F - (XA)M /(XA)M -(XA)S = (0.3 – 0.22)/(0.22 – 0) = 0.36

• (S / F) actual = 1.5 Smin / F = (1.5)(0.36) = 0.54

• F= 495.81 kg/h

• S= (0.54) (495.81 kg/h) = 267.737 kg/h

• Use Material balance to solve R and E

• F + S = E + R

DT = (4 AC/ π)1/2=0.4869 ft

HETS =6.61 ft

Total height = (HETS) (No. of Stages) = 19.83 ft= 6.04418 m

COMPUTER ENGINEERING

• An approach in generating material balance into computer codes.

• Simple algorithm performed to check the material balance at the stirred tank fermentor.

M-FILE

FLOWCHART

• To simplify the computer codes.

• As graphical representation of a series of sequential steps of algorithm.

ENVIRONMENTAL & SAFETY ISSUE

• Waste generation

– waste water

– Waste gas

– Biomass

• Discharge Limit

– Waste water

– Carbon dioxide

• Safety Precautions

– Production plant safety

– Personal safety

– General safety for plant process

– General safety for workers

CONCLUSION

• Citric acid – major production by Aspergillus niger

• Demand in 2012 – 2.9 metric tonnes

• Flow rate = 501.45 kg/hr , Q = -277 053 kJ/s

• Separation by alkyl amide

• Bioreactor of 5.03 m width & 10.06 m height

• Heat transfer in fermenter , q = 632.94W

• Flux = 1.286 x 10-10 kgmol/s.m2

• Column height, H=6.04418m