The project aimed at finding the possible ways in which the abundant amount of rice husk produced each year (around 21 million tons) can be used. After doing a lot of research and experiments it can be concluded that it can be used as a source of electricity as well as a fuel in industry after increasing its carbon content by pyrolysing rice husk at elevated temperatures.

1. 1
EXPLORATORY PROJECT
Model for Rice Husk Utilization
(July 2017-Nov2017)
Presented By,
Avnish Singh 16045118
Patel Vaidikkumar 16045119
B. Tech. Part II
Chemical Engineering
Under the guidance of
Dr. DS Chakraborty

2. 2
Table of Content
Page No.
Acknowledgement 3
Abstract 4
Introduction 4
Literature 5
Proximate Analysis 5
Bomb Calorimeter 6
Pyrolysis 7
Experimental 7
Biomass 7
Proximate Analysis of Rice Husk 8
Calorific Value of Rice Husk 9
Pyrolysis 11
Results and Discussion 11
Use of Rice Husk as a fuel in cogeneration plant 11
Proximate Analysis of Rice Husk 13
Pyrolysis 14
Conclusion 18
References 19

3. 3
Acknowledgement
The success and final outcome of this project required a lot of guidance and assistance from
many people and we are extremely privileged to have got this all along the completion of our
project. All that we have done is only due to such supervision and assistance and we would
not forget to thank them.
We owe our deep gratitude to our project guide Dr. DS Chakraborty, who took keen interest
on our project work and guided us all along, till the completion of our project work by
providing all the necessary information for developing a good system.
We respect and thank Dr. H Pramanik, for providing us an opportunity to do the project work
in Energy Resources Lab, IIT (BHU) Varanasi and giving us all support and guidance which
made us complete the project duly. We are extremely thankful to him for providing such a
nice support and guidance, although he had busy schedule managing academic affairs.
We would not forget to remember Vinay Kumar sir and P Gaud sir, for their encouragement
and more over for their timely support and guidance till the completion of our project work.
We are thankful to and fortunate enough to get constant encouragement, support and
guidance from all Teaching staffs of Department of Chemical Engineering and Technology
which helped us in successfully completing our project work. Also, we would like to extend
our sincere esteems to all staff in laboratory for their timely support.
Avnish Singh 16045118
Patel Vaidikkumar 16045119
B. Tech. Part II
Department of Chemical Engineering and Technology
IIT (BHU) Varanasi

4. 4
Report: Model for Rice Husk Utilization
Avnish Singh and Patel Vaidikkumar
Under the guidance of Dr. DS Chakraborty
Abstract
Every year approximately 120 million tonnes of paddy is produced in India. This gives
around 24 million tonnes of rice husk. In India rice husk is used for cattle feeding, partition
board manufacturing. But theses uses are not in a systematic manner and also rice husk has
very low food value. Being fibrous it can prove to be fatal for the cattle feeding. Use of rice
husk ash or rice husk in land filling is also an environmentally hazardous way of disposing
waste.
In this project we have worked on the various uses of rice husk. The use of rice husk as a
valuable fuel for industries might help in boosting the farm economy and rural development.
India being the second largest rice producer in the world, systematic approach to this material
can give birth to a new industrial sector of rice husk ash in India.
Keywords
Economy, Fuel, Rice Husk, Pyrolysis, Proximate Analysis, Electricity
Introduction
Energy availability in the rural as well as urban areas of India is fast becoming a great
challenge with the high cost of cooking gas and kerosene and environmental problems
associated with firewood. This has drawn attention to the need for an urgent transition to a
more sustainable energy system that would be affordable and eco-friendly. As such many
researches are on-going on the prospects of using agro wastes and other biomass for the
production of solid fuels called briquettes which would serve as substitutes to the depleting
non-renewable energy sources.
A briquette is a block of flammable matter used as fuel to start and maintain a fire. Briquettes
are produced through a process known as briquetting. This process involves the densification
of loose biomass residues, such as sawdust, straw, rice husk etc, into high density solid
blocks that can be used as a fuel. Common types of briquettes are charcoal and biomass
briquettes. Biomass briquettes (including pellets, which are very small briquettes) replace
fossil fuels or wood for cooking and industrial processes. They are cleaner and easier to
handle, and cut greenhouse gas emissions.
The utilization of biomass had a long history until it was largely replaced by fossil fuels such
as petroleum and coal. With the energy crisis and increased environmental pollution in recent
years, biomass energy has attracted attention as a renewable and clean energy resource. Zero
carbon dioxide emission may be realized in the utilization of biomass, and the greenhouse
effect may be reduced.
Biomass energy is a renewable resource that may completely replace fossil fuels because of
its diversity and richness on the earth. India has the second largest rice cultivation region in
the world, and rice husk accounted for 20% of the main by-product. The use of rice husk for
energy may reduce pollution while generating economic benefits.
In this project we have analysed the changes that take place when we pyrolyse rice husk at
various temperatures. We have also looked into the technical and economical aspects of

5. 5
production of electricity in a 5KW power plant in detail. For accomplishing this aspect we
used bomb calorimeter to find the calorific value of rice husk, so as to provide an idea of the
amount of husk required for production of energy.
Literature
Sampling and Preparation for Analysis
Before undertaking an analysis the results of which are to be used to represent the
composition of a consignment of a feedstuff, it is important that the sample is sufficient in
amount and that it is selected properly from the bulk so as to be fairly representative of it.
Sampling is however not a laboratory operation. The sample to be used, if necessary, is
expected to be sufficiently dried to enable it to be finely ground.
Proximate Analysis
This refers to the determination of the major constituents of feed.
Moisture Determination
To determine the moisture content of the feed, the feed is firstly weighed and then kept in a
silica crucible.
Then the crucible is kept in oven and heated for 30 min. at 1080
C.
The crucible is then allowed to cool in desiccators. It is then weighed and the moisture
content is found according to the following formula:
%Moisture =
(wt of sample + dish before drying)− (wt of sample+ dish after drying)
Wt of sample taken
× 100
Ash Determination
To determine the ash content of the feed, the feed is firstly weighed and then kept in a silica
crucible (ash crucible).
Then the crucible is kept in electric furnace and heated for 60 min. at 5000
C.
The crucible is then allowed to cool in desiccators. It is then weighed and the moisture
content is found according to the following formula:
%Ash =
wt of crucible+ash – wt of crucible
Wt of sample taken
× 100
Volatile Matter Determination
To determine the volatile of the feed, the feed is firstly weighed and then kept in a silica
crucible.

6. 6
Then the crucible is kept in electric furnace and heated for 15 min. at 6000
C.
The crucible is then allowed to cool in desiccators. It is then weighed and the moisture
content is found according to the following formula:
%Volatile Matter =
(wt of sample + dish before heating)− (wt of sample+ dish after heating)
Wt of sample taken
× 100
Fixed Carbon
%Fixed Carbon = 100 – (%Moisture + %Ash + %Volatile Matter)
Why do we do proximate analysis?
The following two are the main reasons behind doing proximate analysis:
1. To check if there is any adulteration done in the feed.
2. To compare the contents of various biomasses.
Note:
1. Use tong to put crucible in the oven.
2. Top Pan Balance is used to “Weigh the Whole Sample.” Air should not be allowed to
enter the machine.
Bomb Calorimeter
A bomb calorimeter is a type of constant-volume calorimeter used in measuring the heat of
combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure
within the calorimeter as the reaction is being measured. Electrical energy is used to ignite
the fuel; as the fuel is burning, it will heat up the surrounding air, which expands and escapes
through a tube that leads the air out of the calorimeter. When the air is escaping through the
copper tube it will also heat up the water outside the tube. The change in temperature of the
water allows for calculating calorie content of the fuel.
Basically, a bomb calorimeter consists of a small cup to contain the sample, oxygen, a
stainless steel bomb, water, a stirrer, a thermometer, the dewar or insulating container (to
prevent heat flow from the calorimeter to the surroundings) and ignition circuit connected to
the bomb. By using stainless steel for the bomb, the reaction will occur with no volume
change observed.

7. 7
Bomb Calorimeter
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in
the absence of oxygen (or any halogen). It involves the simultaneous change of chemical
composition and physical phase, and is irreversible. The word is coined from the Greek-
derived elements pyro "fire" and lysis "separating".
Pyrolysis is a type of thermolysis, and is most commonly observed in organic materials
exposed to high temperatures. It is one of the processes involved in charring wood, starting at
200–300 °C (390–570 °F). It also occurs in fires where solid fuels are burning or when
vegetation comes into contact with lava in volcanic eruptions. In general, pyrolysis of organic
substances produces gas and liquid products and leaves a solid residue richer in carbon
content, char. Extreme pyrolysis, which leaves mostly carbon as the residue, is
called carbonization.
Pyrolysis differs from other processes like combustion and hydrolysis in that it usually does
not involve reactions with oxygen, water, or any other reagents. In practice, it is not possible
to achieve a completely oxygen-free atmosphere. Because some oxygen is present in any
pyrolysis system, a small amount of oxidation occurs.
The term has also been applied to the decomposition of organic material in the presence
of superheated water or steam (hydrous pyrolysis), for example, in the steam cracking of oil.
Experimental
Biomass
The biomass sample used in this project is rice husk from plantations in Faculty of
Agricultural Sciences, BHU.
The sample was sun-dried and was then kept in hot air electric- oven for 30 min to remove
moisture. The sample was then kept in desiccators.

8. 8
Desiccators Used
Proximate Analysis of Rice Husk
Characteristics of Rice Husk and Lignite
Characteristics Rice husk Lignite
Proximate analysis (wt %)
moisture 01.6688 13.9
ash 13.1083 15.5
volatile matter 70.1622 40.1
fixed carbon 15.0607 44.4
Furnaces and Oven Used in Proximate Analysis

9. 9
Calorific Value of Rice Husk
Fuse Wire Used: Nichrome Wire
Pressure of O2: 25lb/inch2
Apparatus Used: Bomb, Jacket, Digital Bomb Calorimeter
Water Bath (Volume): 1750mL
Room Temperature: 31.40
C
ΔT: 1.630
C
Time of Experiment: 30min
Formula Used
CV= (W× ΔT – (CV t + CV w))/M
CV t : CV of thread
CV w : CV of Nichrome Wire
W : Water Equivalent
Tablet Maker Machine
Tablet formation for Calorific Value
Rice Husk was weighed and then put in the Tablet Maker.
Mass of feed taken initially = 1.1g
Mass of tablet formed = 0.9479g
 The mass that is put in the machine is not exactly converted into tablet. Some of it
sticks the walls of the machine. Thus, it is important to weigh the sample after it gets
formed.
If the sample is not easily convertible into tablet then a small amount of additive is
used.

10. 10
Table for ΔT vs. Time in Bomb Calorimeter Experiment
Time(in min) ΔT(0C)
1 0.45
2 0.80
3 0.97
4 1.13
5 1.20
6 1.26
7 1.30
8 1.35
9 1.38
10 1.42
11 1.45
12 1.47
13 1.48
14 1.50
15 1.52
16 1.54
17 1.55
18 1.56
19 1.57
20 1.58
21 1.58
22 1.59
23 1.60
24 1.60
25 1.61
26 1.62
27 1.62
28 1.63
29 1.63
30 1.63

11. 11
Pyrolysis
Rice husk was pyrolysed at a temperature 5000
C, 6500
C and 8000
C to see what changes come
in the proximate analysis of the char obtained. The result obtained shall define on what can
be the use of biomass as a cleaner and efficient fuel.
Dimensions of the Grey King Analysis Tube:
Length = 29.2cm Diameter = 23.2mm
Glass wool was used to prevent losses. The amount of feed was less than 10g.
Grey King Analysis Tube and Reactor Used for Pyrolysis
Results and Discussion
Calorific Value of Rice Husk
CV= (W× ΔT – (CV t + CV w))/M
= (2248×1.63 – (21+9.31))/0.9479 = 3833.6639 Cal.
Use of Rice Husk as a fuel in Cogeneration Plant
Rice husk boilers are being used throughout the country for the generation of process steam
at a large number of locations. The decision regarding the choice of fuel for process steam is
made based on the availability of rice husk, other techno-commercial consideration and cost
benefits. Small-sector process industries use fixed, great fire-tube boilers with low capacity,
which are manually fired, using rice husk as a fuel. These industries employ primitive boiler
designs and combustion practices and thus face the problems of partial fuel combustion and
low efficiency. Partial and uneven combustion of husks in the furnaces of the boilers also
leads to smoke emissions. Combusted rice husk gives Rice Husk Ash (RHA). Many more

12. 12
plants in range of 2-10 MW range can become commercially viable in the country and this
biomass resource can be utilized to a much greater extent than at present.
In this project we have discussed the use of rice husk in cogeneration power plants of
capacity varying from 2MW to 10 MW.
The technical and economical analysis is as follows. Energy balance and related analysis
of 5 MW power plants are given below:
Energy Balance and Related Analysis of 5 MW Power Plants
Given,
Number of hours for which the plant runs in a day= 24hours
Number of days of operation in a year= 350 days
Minimum amount of electricity generated will be= 5 x 24 x 350 = 42000 MWh/year.
Amount of heat required to be produced to produce 42000MWh/year = 42000 x 3600 =
151200 GJ/year
Considering that the approximately 30% of the heat generated in boilers is converted into
electricity, the heat that must be provided by the boiler= 151200÷ 0.3 = 504000 GJ/year
Calorific Value of Rice Husk = 4.184 x 3833.6639 x 103
= 16.04 GJ/tonne.
Quantity of rice husk required considering that combustion efficiency is 80%
= (504000 ÷ 0.80) ÷ 16.04 = 39277 tonnes/year (approx.)
For 42000 MWh of electricity, rice husk required is 39277 tonnes.
Thus, to produce 1 MWh of electricity, rice husk required is 0.935 tonne.
Amount of Rice Husk Ash (RHA) produced = 13.1083% x 39277 = 5148.55 tonne/year
Costs Benefit Analysis of using Rice Husk as a Fuel in the 5 MWh Power Plants
Number of units produced in one hour will be 5000 KWh (5000 units)
We have assumed that production cost is approximately equal to Rs. 2/KWh.
Any industry persons would be ready to have power at Rs.2/KWh
Cost of 5MWh = Rs. 10000.
Considering cost of fuel at 50 % of production cost, fuel cost will be Rs.1000/MWh.
(10000 x 0.50) ÷5 = Rs.1000/MWh
Cost of purchasing one truck load of rice husk, of pay load capacity of 8 tonnes, will be
Rs. 8000 to produce 8.556 MWh. Let us consider Rs. 4000/truck is the cost of rice husk at
rice mill and Rs.4000/truck is the transportation cost of rice husk from rice mill to Power
Plant. In Rs.4000/truck it is practically possible to convey the rice husk from the distance of

13. 13
100kms. In this case rice mill owner will earn around Rs. 500/tonne from Rice Husk. If half
of this profit is transferred to farmers will get around Rs. 250/tonne.
Along with there are several fiscal incentive given by the Government of India like,
Accelerated Depreciation on high efficiency equipment, tax holiday for five years and 30%
exemption for next five years, exemption on central excise duty for renewable energy
devices, including raw materials, components and assemblies. According to statistics
available rice husk can be made available throughout year in the Northern, Southern, North-
eastern and Eastern regions baring Western region.
This analysis clearly indicates that captive power plants in the range of 2-8 MW range are
practically feasible.
Proximate Analysis of Rice Husk
Moisture
Feed of rice husk was kept in moisture dish and heated in oven at 1080C for 30 minutes.
Wt. of moisture dish = 14.9393g
Wt. of moisture dish with feed = 15.9340g
Wt. of feed = 0.9947g
Wt. of dish after heating in oven = 15.9174g
% of moisture =
15.9340−15.9174
0.9947
× 100 = 1.6688%
Ash
Feed of rice husk was kept in ash crucible and heated in electric furnace at 5000C for 1 hour.
Wt. of ash crucible with lid = 17.0655g
Wt. of crucible with feed = 18.0786g
Wt. of feed = 1.0131g
Wt. of crucible after heating = 17.1983g
% of ash =
17.1983−17.0655
1.0131
× 100 = 13.1083%
Volatile Matter
Feed of rice husk was kept in volatile crucible and heated in muffle furnace at 6000C for
15 minutes.
Wt. of volatile crucible with lid = 12.8264g
Wt. of crucible with feed = 13.8620g
Wt. of feed = 1.0356g
Wt. of crucible after heating = 13.1354g
% of volatile matter =
13.8620−13.1354
1.0356
× 100 = 70.1622%
Fixed Carbon
% of fixed carbon = 100 – (1.6688+13.1083+70.1622)
= 15.0607%

14. 14
Pyrolysis Result
Pyrolysis at 5000C
Mass of the tube = 67.3485g
Mass of tube after putting feed (rice husk) = 75.2058g
Mass of feed = 7.8573g
Mass of tube after pyrolyzing = 72.7472g
Mass of the char obtained = 5.3987g
Proximate Analysis of the char obtained by pyrolyzing at 5000C
Moisture
Feed of rice husk was kept in moisture dish and heated in oven at 1080C for 30 minutes.
Wt. of moisture dish = 14.9399g
Wt. of moisture dish with feed = 15.8965g
Wt. of feed = 0.9566g
Wt. of dish after heating in oven = 15.8815g
% of moisture =
15.8965−15.8815
0.9566
× 100 = 1.5681%
Ash
Feed of rice husk was kept in ash crucible and heated in electric furnace at 5000C for 1 hour.
Wt. of ash crucible with lid = 17.0545g
Wt. of crucible with feed = 17.8961g
Wt. of feed = 0.8416g
Wt. of crucible after heating = 17.2440g
% of ash =
17.2440−17.0545
0.8416
× 100 = 22.5166%
Volatile Matter
Feed of rice husk was kept in volatile crucible and heated in muffle furnace at 6000C for
15 minutes.
Wt. of volatile crucible with lid = 12.8260g
Wt. of crucible with feed = 14.2176g
Wt. of feed = 1.3916g
Wt. of crucible after heating = 13.7201g
% of volatile matter =
14.2176−13.7201
1.3916
× 100 = 35.7502%
Fixed Carbon
% of fixed carbon = 100 – (1.5681+22.5166+35.7502)
= 40.1651%

15. 15
Pyrolysis at 6500C
Mass of the tube = 67.1460g
Mass of tube after putting feed (rice husk) = 75.3174g
Mass of feed = 8.1714g
Mass of tube after pyrolyzing = 71.4745g
Mass of the char obtained = 4.3285g
Proximate Analysis of the char obtained by pyrolyzing at 6500C
Moisture
Feed of rice husk was kept in moisture dish and heated in oven at 1080C for 30 minutes.
Wt. of moisture dish = 14.9385g
Wt. of moisture dish with feed = 16.6467g
Wt. of feed = 1.6308g
Wt. of dish after heating in oven = 16.5630g
% of moisture =
16.6467−16.5630
1.6308
× 100 = 5.1876%
Ash
Feed of rice husk was kept in ash crucible and heated in electric furnace at 5000C for 1 hour.
Wt. of ash crucible with lid = 17.0546g
Wt. of crucible with feed = 17.6767g
Wt. of feed = 0.6221g
Wt. of crucible after heating = 17.1944g
% of ash =
17.1944−17.0546
0.6221
× 100 = 22.4723%
Volatile Matter
Feed of rice husk was kept in volatile crucible and heated in muffle furnace at 6000C for
15 minutes.
Wt. of volatile crucible with lid = 12.8264g
Wt. of crucible with feed = 14.3750g
Wt. of feed = 1.5486g
Wt. of crucible after heating = 13.9817g
% of volatile matter =
14.3750−13.9817
1.5486
× 100 = 25.3971%
Fixed Carbon
% of fixed carbon = 100 – (5.1876+22.4723+25.3971) = 46.9431%

16. 16
Pyrolysis at 8000C
Mass of the tube = 66.0248g
Mass of tube after putting feed (rice husk) = 75.6131g
Mass of feed = 9.5883g
Mass of tube after pyrolyzing = 70.6247g
Mass of the char obtained = 4.5999g
Proximate Analysis of the char obtained by pyrolyzing at 8000C
Moisture
Feed of rice husk was kept in moisture dish and heated in oven at 1080C for 30 minutes.
Wt. of moisture dish = 16.4418g
Wt. of moisture dish with feed = 17.5660g
Wt. of feed = 1.1242g
Wt. of dish after heating in oven = 17.5648g
% of moisture =
17.5660−17.5648
1.1242
× 100 = 0.1067%
Ash
Feed of rice husk was kept in ash crucible and heated in electric furnace at 5000C for 1 hour.
Wt. of ash crucible with lid = 17.8480g
Wt. of crucible with feed = 18.6912g
Wt. of feed = 0.8432g
Wt. of crucible after heating = 18.1229g
% of ash =
18.1229−17.8480
0.8432
× 100 = 32.6020%
Volatile Matter
Feed of rice husk was kept in volatile crucible and heated in muffle furnace at 6000C for
15 minutes.
Wt. of volatile crucible with lid = 12.6700g
Wt. of crucible with feed = 14.0697g
Wt. of feed = 1.3997g
Wt. of crucible after heating = 14.0072g
% of volatile matter =
14.0697−14.0072
1.3997
× 100 = 4.4652%
Fixed Carbon
% of fixed carbon = 100 – (0.1062+32.6020+4.4652)
= 62.8261%

17. 17
Graphs Depicting Experimental Observations
0
10
20
30
40
50
60
70
80
Rice Husk Pyrolyis product
at 500°C
Pyrolyis product
at 650°C
Pyrolyis product
at 800°C
%Content
Variation in Composition with Pyrolysis
Moisture
Volatile Matter
Ash Content
0
10
20
30
40
50
60
70
Rice Husk Pyrolysis
Product at 500°C
Pyrolyis product
at 650°C
Pyrolyis product
at 800°C
Fixed Carbon Content
Fixed Carbon Content

18. 18
Conclusion
Rice Husk can be used as a potential fuel in Power Plants keeping into consideration the
major crisis of sources of energy. It will be environment friendly as well as produce a good
amount of profit.
Secondly, the fixed carbon content of rice husk can be increased by pyrolyzing it at elevated
temperatures. With the increase in fixed carbon content there is a decrease in volatile matter
and hence it turns out to be good fuel for industrial purposes.
Tablets of the char obtained (if not possible to make tablets directly, then by adding some
additives) can be made and used in industry.
On pyrolyzing rice husk at elevated temperature, the fixed carbon content even becomes
better than that of lignite.
Future Prospects
 Analysing the energy consumed in the pyrolysis process and the calorific value
evaluation of the char obtained from pyrolysis.
 Designing of a reactor to pyrolyze a large amount of husk at the same time.
 Studying the possible chances of error during the experimentation.
 Cost analysis of the fuel obtained by the pyrolysis of rice husk at elevated
temperatures.

19. 19
References
1. Waste to Wealth – Potential of Rice Husk in India a Literature Review M.R. Gidde
and A.P. Jivani
2. Xin-Ping Xie, Xiao-Dong Zhang, Lei Chen, Lai-Zhi Sun & Hong-Yu Si (2015)
Characterization of Rice Husk by Pyrolysis–Gas Chromatography–Mass
Spectrometry, Instrumentation Science & Technology
3. Physical and Thermochemical Properties of Rice Husk K. G. MANSARAY & A. E.
GHALY
4. Arun, K.; Raghunandana, K.S.; Asraf, A.; Ashok, M.; Thimmappa, B.H.S. Rapid
online Monitoring of a Heterogeneous Catalyst by a Pulsed Reactor Coupled to GC-
MS. Instrument. Sci. Technol. 2013,41, 666–679
5. The Physical, Proximate and Ultimate Analysis of Rice Husk Briquettes Produced
from a Vibratory Block Mould Briquetting Machine Andrew Ndudi Efomah and
Agidi Gbabo
6. https://www.unaab.edu.ng/attachments/459_ANN509%20Lecture%20Note%20_A_.p
df
7. Characterization of Rice Husk for Cyclone Gasifier I. Mohamad Yusof, N.A. Farid,
Z.A. Zainal and M. Azman
8. Utilization of Rice Husk and Their Ash: A Review Kumar S., Sangwan P., Dhankhar
R. Mor V., and Bidra S.
9. Properties and Industrial Applications of Rice husk: A review Ajay Kumar, Kalyani
Mohanta, Devendra Kumar and Om Parkash
10. Pyrolysis of rice husk Anshu Bharadwaj, Y. Wang, S. Sridhar and V. S. Arunachalam
11. Qiang, L.; Zhe, T.; Ying, Z.; Xifeng, Z. Catalytic Upgrading of Biomass Fast
Pyrolysis Vapors with Pd=SBA-15 Catalysts. Ind. Eng. Chem. Res. 2010, 49, 2573–
2580