DISCUSSION ON UTILIZING AMMONIA FOR CAPTURING CO₂ AND PRODUCING FERTILIZERS
presentation
1. University of Khartoum
Faculty of Engineering
Department of Chemical Engineering
Ceramic products manufacture
By:
Amel Elsadig Alamir 092006
Shadin Hisham Suliman 092026
Maram Mujahid Mamon 092046
Supervised by:
Dr. Kmal Al deen Altayeb Yassin.
September 2014
2. • Introduction.
• Process description.
• Material balance.
• Energy balance.
• Equipment Designs.
Outlines
• Ancillaries design.
• Process control.
• Safety and environmental considerations.
• Layout.
• Economical evaluation.
3. objectives
• Plan a modern plant for ceramics production.
• The demand for ceramic in Sudan is large, but production rate is relatively small and it’s
covered from importing from Germany and Italy.
• The objective of the plant is to satisfy the local demand and to the export rest to achieve
financial revenues.
4. Introduction
Ceramics : a class of inorganic, nonmetallic materials that are typically made by taking mixtures of clay,
earthen elements, powders, and water and shaping them into desired forms by pressure and heat.
Properties:
hard, wear-resistant, brittle, refractory, thermal insulators, electrical insulators, non-magnetic oxidation
resistant, prone to thermal shock, less dense than most metals, and chemically stable.
Types:
traditional ceramics:
_pottery
_white ware (Earthenware, stoneware, chinaware, porcelain)
Advanced ceramics:
_oxides
_non-oxides
_composites
Applications:
Tiles, art-ware, kitchenware, ovenware, tableware, ball mill balls and liners, chemical-ware, insulators,
and table-ware.
advanced: cut and polish metals, in gas-turbine engines, electronic products, aerospace and automotive
engine components, pump parts, bearing sleeves and valve, microwave plasma, LED, semiconductor chips.
Some ceramics are compatible with bone and tissue.
5. Raw materials used for unglazed wall and floor tiles:
Clays (ball clay, black clay, UK clay): high plasticity.
Kaolin: contributes to Mullite forming.
Feldspar: as fluxing agent and reduces firing temperature.
Calcite: modifies the reactivity of the clayey minerals, and leads to the
formation of anorthite.
Silica: decrease plasticity, reduce shrinking, and balance the viscosity.
7. Total material balance
Total losses of 2% per day.
Water is added later to the raw materials.
Assumptions in the kiln:
90% conversion of the decomposition reaction of kaolinite.
90% conversion of the decomposition reaction of calcite.
Conversion of 42.64921 % of total metakaolin.
Selectivity of 90.139854 % for mullite from reacted
metakaolin.
Raw material Chemical
composition
In term of oxides Percentag
e (%)
Feldspar KAlSi3O8 1/2
(K2O.Al2O3.6SiO2) 30
Kaolin (china)
clay
Al2Si2O5(OH)4 Al2O3.2SiO2.2H2O
20
Ball clay Al2Si4O9(OH)4 Al2O3.4SiO2.2H2O
20
Black clay Al2Si4O9(OH)4 Al2O3.4SiO2.2H2O
10
UK clay Al2Si4O9(OH)4 Al2O3.4SiO2.2H2O
10
calcite CaCO3 CaO.CO2 6
silica SiO2 - 4
production rate = 200 ton/day. Working 24hr/day, 300
days/year.
9. 0
100
200
300
400
500
600
700
800
900
1000
1100
0 0.5 1 1.5 2 2.5 3 3.5
KILN HEAT BALANCE
Total heat balance
Assumptions:
The remaining moisture is released as sat. vapor at 130 C°.
The gases are released as soon as they are formed , carbon
dioxide at 850 C° , water vapor at 130 C°, and lattice water
vapor at 550 C°.
kaolin ∆𝐻𝑟 = +146.44 𝑘𝑗/𝑚𝑜𝑙
Calcite ∆𝐻𝑟 = +9.5512𝑘𝑗/𝑚𝑜𝑙
Mullite ∆𝐻𝑟 = −509.1505 𝑘𝑗/𝑚𝑜𝑙
Anorthite ∆𝐻𝑟 = −111.78808 𝑘𝑗/𝑚𝑜𝑙
= 7.597 tons
10. Ball mill design
Bond method: depends on a standard laboratory test to obtain
the material work index. Then calculating the power
consumption and relate it to the ball length and diameter.
Denver model: is derived for the various types of ore referring to
its hardness: soft ore, hard ore, or medium ore.
specification Bond’s method Denver’s
model
Mill diameter (m) 3.237 3.287
Mill length (m) 4.8555 4.93074
Mill power (kw) 644.585 919.9907
Actual rotating speed
(rpm)
16.4635 16.3374
Top ball size (mm) 34.1873 31.846
Charge height (m) 2.1323 2.1654
Loading (%) 30.9887 30.97361
Residence time (min) 1.7336 1.91226
Grinding conditions:
Feed size =2.624 mm, product size = 0.08338 mm
30% balls loading, 0.7 fraction of critical speed
L/D = 1.5, operating 6 hr/day (55 ton/hr).
Materials of construction:
The balls are made of steel.
The inner surface is lined with rubber.
The mill is made of mild steel which has a carbon
content of 0.15%.
11. Ball mill control
In closed-circuit system a classifier returns coarse
material back to the mill feed.
Using decentralized PID controller.
General process transfer function 𝐺 𝑃 =
𝐾
𝜏𝑆+1
. 𝑒−𝑇 𝑑 𝑆
Problems with decentralized PID controller are solved
using Detuned multi-loop PID controller, introducing de-
couplers.
Process Ball mill
Controlled variable Particle size of classifier over flow.
Classifier feed rate.
Measuring element Classifier.
Regulating element Weight feeders
Manipulated element Fresh solids feed rate.
Dilution water.
Load variables mill critical speed fraction.
ore hardness changes.
feed size variations.
12. Kiln performance as a reactor
Since anorthite formation and calcite decomposition have little
contribution to the final products, they can be neglected.
Kaolin kinetics: −𝑟𝐴 = 𝑘. 𝐶𝐴
𝑛
= 2.21 × 108. 𝑒
−242000
8.314.𝑇 𝐶𝐴
3
Mullite kinetics: −𝑟𝐴 = 𝑘. 𝐶𝐴 = 8.21 × 1022. 𝑒
−599000
8.314.𝑇 𝐶𝐴
𝑇 = 𝑇0 + 𝜃. 𝑡, and 𝑑𝑡 =
𝑑𝑇
𝜃
where 𝜃 is the heating rate
𝑋𝐴 = 1 −
𝐶 𝐴
𝐶 𝐴0
= 94.65% at 950°C , and 99.896% at 1190°C
𝑋 𝑅 = 1 −
𝐶 𝑅
𝐶 𝑅0
= 0.01484% at 1190°C 0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400 1600
T vs X
kaolin
3 Al2Si2O5(OH)4 3 Al2Si2O7 + 6 H2O 3 Si₂Al₆O₁₃ + 4 SiO₂
3 CaCO3 3 CaO + 3 CO2. 3 [CaO.Al2O3.2SiO2]
kaolin Meta kaolin mullite
anorthit
e
calcite
500-600 °C > 980 °C
800-900 °C
> 1000 °C
13. kiln selection (roller hearth kiln)
RHK is more efficient than tunnel kilns.
Heating sections of the kiln :the pre-kiln, the pre-heating zone, the
high temperature firing zone.
Cooling sections: the rapid cooling zone, the gentle cooling zone, the
final cooling zone.
RHK parameters value
Maximum firing
temperature
1190°C
firing atmosphere oxidizing
Dimensions 15 * 2.3
m
Combustion fuel LPG
14. Roller hearth kiln control
The mathematical model of the system is:
𝐺 𝑃 =
𝐾
𝜏𝑆 + 1
. 𝑒−𝐿𝑆
First by P-controller: which may lead either to oscillation or take a
relative long time.
Second by PID-controller:
D-action: reduces oscillation and settling time.
I-action: reduces steady-state error.
Tuning the system by finding critical gain and critical time period
associated with it.
based on Ziegler-Nichols method 𝐾 𝑃, 𝐾𝐼, and 𝐾 𝐷 gain values are
parameter Ziegler-Nichols PID controller tuning formula
Ti
𝑇𝑖 =
𝑇𝐶
2
Td
𝑇𝑑 =
𝑇𝐶
8
KP 𝐾 𝑝 = 0.6 × 𝐾𝐶
Process Roller hearth kiln
Controlled variable Temperature at various
locations in the kiln.
Measuring element Thermocouple.
Regulating element Valve.
Manipulated
element
LPG flow rate.
Load variables ambient temperature.
Humidity.
Fuel quality.
Materials load.
15. Ancillaries design
tanks Material
handled
Amount
(kg/day)
Volume
(m³)
Fixed roof
tanks
slurry 330102.6978 301
Open top tank Dust powder 225859.7406 128
Ball mill
classifier
Material
handled
Amount
(kg/hr)
separation of
particles
Product diameter
(µm)
Diameter of hydro-cyclone
(cm)
hydro-cyclone slurry 55017.1163 90% 83.38 80
Pump(101) Head (m) Power (KW) Rotational velocity
(rpm)
Capacity (𝑚3
/ℎ)
Horizontal centrifugal
pump
18 m 4 2000 8.574
Air
heater
Gas
type
Dimensions
(mm)
Weight
(kg)
Heat output
(KW/h)
Steam
heated
LPG 423*80*94 3.8 2.4
Cyclone Efficien
cy
Ring leman
blackness
Emission
concentration
Dry cyclone 97 % 0.5 50
16. Spray Dryer Design
Specifications:
Drying intensity 26.21709
(Kg/𝑚3)
Power 38.00136988 kw
Efficiency 92.3077%
Wheel atomizer diameter 6 m
Chamber height 18 m
Droplet diameter 0.000355 m
Particle size diameter 0.000037261 m
Inlet air temperature 600˚C
Outlet air temperature 120˚C
Outlet moisture content 5%
Van type Rectangular van
Liquid-air layout Co-current
Material od construction Stainless steel
17. Control of spray dryer
the moisture content is not directly measurable, it is indirectly controlled by
maintaining the outlet air temperature at a set value by varying either the
feed rate to the dryer or the main inlet air drying temperature (feedback
control strategy).
The temperature control system by feed rate variation. Gfeed(s) is the
transfer from feed input to output. Gc - controller transfer function. Gsolid(s)
is the transfer function of the disturbance
19. Hydraulic press control
Process Hydraulic press
Controlled variable Position of piston.
Measuring element Flow rate indicator.
Regulating element Valve of the oil.
Manipulated element Oil flow rate.
20. Dryer design
Flow rate of hot air (Gₒ) 4 m/s
Flow rate of wet
material(Fₒ)
0.128077 kg
wet/s
Flow rate of dry material
(Fdₒ)
0.121979 kg dry/s
Inlet air temperature (Tgₒ) 300°C
Outlet air temperature (Tg₁) 130°C
Temperature of wet material
(Tₒ)
35°C
Temperature of dry material
(T₁)
100°C
Moisture content of wet
material (wₒ)
0.05
Moisture content of dry
material (w₁)
0.003
Length of the dryer at
critical moisture content
(Zc)
1.3 m
21. environmental considerations
SO₂: function of sulfur content of fuel used, sulfur content of raw materials.
NOₓ:The raw flue gas but the raw flue-gas coming from spray dryer contains more Nox.
Greenhouse Gas(GHG): especially CO₂, the volume of these pollutant depends on the use of energy in
the kiln and spray dryer.
Emissions of HF: from the kiln when raw materials contain fluorine impurities.
Volatile organic compounds(VOC): from incomplete combustion and volatilization of the organics with
the raw material.
particulate matter: PM less than 10μm
How do we reduce these emissions???
Air emissions
Waste water
Solid waste
22. Health& safety issues
Types of hazards:
- Respiratory hazard.
- exposure to heat.
- exposure to noise/vibration.
- physical hazard.
- electrical hazards.
23. Respiratory hazard:
silica dust is crystalline silica that may become respirable size particles when
work chip, cut, drill and grind quarts that contain crystalline silica .
Silicosis: is a disease caused by the prolonged breathing of crystalline silica
dust.
A worker may develop any of the following three types of silicosis:
1. Chronic silicosis
2. Accelerated silicosis
3. Acute silicosis
What do to help protect workers from silica exposure??
24. Plant location and layout
To choose the best location we have to Consider the following factors:
- market and transportation
-climate
- raw material
- labor & water supply
- waste disposal
-site characteristics
The best location is west Omdurman.
For plant layout we must consider the type an quantity of product, types of process, economic
distribution of utilities, health an safety considerations, space availability and finally roats and
railways.
26. • Costs of equipment were obtained from quotations. Tanks
costs were estimated and modified for production year.
• The following assumptions were made:
The plant life span is twenty years.
All costs in U.S. Dollar when it equals 9 SDG on September 2012.
The price of raw materials, catalyst and product is fixed for the whole
period of operation.
Interest rate is taken as 15%.
Economic evaluation
27. Costs are determined as follows
Total capital investment Value
Fixed capital investment $
8,186,141.22
Working capital investment $
818,614.1221
Total capital Investment
(10% working capital)
$
9,004,755.34
Total product cost (TPC) Value
Manufacturing cost components:
Fixed charges (depreciation, insurances and local taxes) $ 818,614.122
Direct production cost (raw materials, operating labor, utilities, …) $ 8,642,538.095
Plant overheads $ 1,999,579.888
Total Manufacturing cost $ 11,460,732.1
General expenses (administrative costs, interest, distribution costs and research) $ 4,130,177.97
Total product cost (operating cost) $ 15,590,910.07
28. Sensitivity analysis $1,916,913.09
Net Present value
(NPV)
$9,421,758.741
Internal rate of
return(IRR)
32.06853%
Profitability Index(PI) 2.04631
Pay back period (PBP) 3.142 years
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
9000000
10000000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
cash flow diagram
income WCI TCI
Sensitivity analysis
29. Results and recommendations
Respiratory hazards in the ceramic manufacturing process are of a great
importance, therefor most care must be taken for this kind of risks.
The power consumption in ceramic manufacturing is considered very
high, so its recommended to use either more efficient equipment or more
efficient process.
Better understanding of basic raw materials of ceramic can result in
different efficient recipes.
Ceramics manufacturing is based on years of practice due to the
complications of clay minerals and their interactions.
