Use of scrap tires in cement production and their impact on nitrogen and sulfur oxides emissions

Abstract

Cement production is characterized by extremely high energy consumption per unit of product. Energy costs and environmental standards encouraged cement manufacturers worldwide to evaluate to what extent conventional fuels can be replaced by alternative fuels, i.e., processed waste materials, such as scrap tires. The decisive factors promoting the use of cement kilns for the utilization of scrap tires are: the high incineration temperature, the large area of the furnace, the significant length of the kiln, the long period of time the fuel stays inside the kiln, and the alkaline environment inside the kiln. The use of scrap tires in cement kilns is one of the best technologies for a complete and safe destruction of these wastes, due to the fact that there is a simultaneous benefit of destroying wastes and getting the energy. Thus, the use of scrap tires as alternative fuel in cement kilns has energy and economic justifiability, and it is environmentally friendly. In this article, monitoring results of nitrogen and sulfur oxides emissions from cement kilns in a cement factory in Serbia are given, depending on the ratio of scrap tires in total fuel quantity. Research was carried out for 0 to 15% share of scrap tires in total heat production. Nitrogen and sulfur oxides emission measurements from cement kilns were done during a trial use of scrap tires as a secondary fuel in a cement factory. During nitrogen and sulfur oxides emissions monitoring from the cement kiln, coal and petroleum coke were used as primary fuel, and whole or shredded tires were used as secondary fuel. Experimental results have shown the encouraging results: in particular, clinker characteristics were unmodified, and stack emissions of NOx and SO2 were, in the case of tires, slightly decreased, in some cases were incremented, but remaining always below the law imposed limits.

Full text

Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=ueso20
Download by: [Zoran Cepic] Date: 10 February 2016, At: 01:04
Energy Sources, Part A: Recovery, Utilization, and
Environmental Effects
ISSN: 1556-7036 (Print) 1556-7230 (Online) Journal homepage: http://www.tandfonline.com/loi/ueso20
Use of scrap tires in cement production and their
impact on nitrogen and sulfur oxides emissions
B. Nakomcic-Smaragdakis, Z. Cepic, N. Senk, J. Doric & Lj. Radovanovic
To cite this article: B. Nakomcic-Smaragdakis, Z. Cepic, N. Senk, J. Doric & Lj. Radovanovic
(2016) Use of scrap tires in cement production and their impact on nitrogen and sulfur oxides
emissions, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 38:4,
485-493, DOI: 10.1080/15567036.2013.787473
To link to this article: http://dx.doi.org/10.1080/15567036.2013.787473
Published online: 08 Feb 2016.
Submit your article to this journal
View related articles
View Crossmark data

Use of scrap tires in cement production and their impact on
nitrogen and sulfur oxides emissions
B. Nakomcic-Smaragdakis
a
, Z. Cepic
a
, N. Senk
a
, J. Doric
a
, and Lj. Radovanovic
b
a
University of Novi Sad, Faculty of Technical Sciences, Novi Sad, Serbia;
b
University of Novi Sad, Technical Faculty
“Mihajlo Pupin”, Zrenjanin, Serbia
ABSTRACT
Cement production is characterized by extremely high energy consumption
per unit of product. Energy costs and environmental standards encouraged
cement manufacturers worldwide to evaluate to what extent conventional
fuels can be replaced by alternative fuels, i.e., processed waste materials,
such as scrap tires. The decisive factors promoting the use of cement kilns
for the utilization of scrap tires are: the high incineration temperature, the
large area of the furnace, the significant length of the kiln, the long period
of time the fuel stays inside the kiln, and the alkaline environment inside
the kiln. The use of scrap tires in cement kilns is one of the best technol-
ogies for a complete and safe destruction of these wastes, due to the fact
that there is a simultaneous benefit of destroying wastes and getting the
energy. Thus, the use of scrap tires as alternative fuel in cement kilns has
energy and economic justifiability, and it is environmentally friendly. In this
article, monitoring results of nitrogen and sulfur oxides emissions from
cement kilns in a cement factory in Serbia are given, depending on the
ratio of scrap tires in total fuel quantity. Research was carried out for 0 to
15% share of scrap tires in total heat production. Nitrogen and sulfur oxides
emission measurements from cement kilns were done during a trial use of
scrap tires as a secondary fuel in a cement factory. During nitrogen and
sulfur oxides emissions monitoring from the cement kiln, coal and petro-
leum coke were used as primary fuel, and whole or shredded tires were
used as secondary fuel. Experimental results have shown the encouraging
results: in particular, clinker characteristics were unmodified, and stack
emissions of NOx and SO
2
were, in the case of tires, slightly decreased, in
some cases were incremented, but remaining always below the law
imposed limits.
KEYWORDS
Alternative fuel; cement
industry; nitrogen oxides
emission; scrap tires; sulfur
oxides emissions
1. Introduction
Cement is the main component of concrete, which is, in turn, the second most consumed material
on earth; in addition, the cement industry has one of the most intensive energy consumptions. The
modern plants often have nominal production capacity exceeding one million tons per year (Lamas
et al., 2013). The worldwide production of cement has more than quadrupled over the last 25 years,
reaching 3 million tons in 2009. Production is expected to further increase because of the exponen-
tial growth rates in developing countries, such as China and India, which are the major cement
producersintheworld(Oggionietal.,2011).
It is estimated that the cement industry is responsible for approximately 2% of the world’s
primary energy consumption (Nielsen, 2012). Fossil fuels, such as coal and petroleum coke, have
CONTACT Lj. Radovanovic ljiljap@tfzr.uns.ac.rs University of Novi Sad, Technical faculty “Mihajlo Pupin”, Djure Djakovic
bb, 23000 Zrenjanin, Serbia.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ueso.
© 2016 Taylor & Francis
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS
2016, VOL. 38, NO. 4, 485–493
http://dx.doi.org/10.1080/15567036.2013.787473
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

traditionally been used as energy sources in the cement manufacturing industry; however, in recent
decades, these fuels are increasingly being substituted with alternative, typically residue-based sources
(e.g., sorted municipal solid waste, tires, and waste wood) (Albino et al., 2011; Zabaniotou et al.,
2002).
Many years of experience have shown that the use of wastes as alternative fuels by cement plants
is both ecologically and economically justified. The use of alternative fuels will help reduce the costs
of cement production.
The main end-markets for scrap tires are tire-derived fuel (TDF); civil engineering applications;
ground rubber applications; and cut, punched, and stamped rubber products.
While tire-derived fuel is the major end-market in most countries at the moment, growth in civil
engineering applications is likely to be much stronger over the long term as the latter is more
profitable. However, in Europe, tire-derived fuel could benefit in the short term. This is because the
demand from civil engineering market takes more time to get established than tire-derived fuel. As
supply takes off the civil engineering market might not be able to absorb the excess supply, some of
which could be diverted for use as fuel.
The average energy demand for the production of one ton of cement is about 3.3 GJ thermal
energy, which corresponds to 120 kg of coal with a calorific value of 27.5 MJ/kg and approximately
110 kWh/t of electrical energy (with 40% directed to clinker grinding) (Mokrzycki and Uliasz-
Bocheńczyk, 2003;Jankovicetal.,2004). Thermal energy accounts for about 20–25% of the cement
production cost (Madlool et al., 2011). The main thermal energy is used by burning processes, while
cement grinding consumes electrical energy (Madlool et al., 2013). On average, energy costs, in the
form of fuel and electricity, represent 40% of the total production costs for one ton of cement
(Oggioni et al., 2011). The substitution of fossil fuels with alternative fuels will help reduce energy
costs and therefore production costs, providing a competitive edge for a cement plant using this
source of energy.
The capital costs associated with modifying feed and emission control equipment for TDF
burning in cement kilns are minor in most cases. Therefore, the cost savings from TDF is essentially
equal to the savings in fuel cost by using TDF in the kiln. This fuel cost advantage is attractive to
cement plants because the process is so energy intensive. However, cement kilns can accommodate
many alternate fuels, so that regional availability and price of alternatives may affect the cost
advantage. Because of their consumption, cement plants are able to buy conventional fuels in bulk
and at somewhat lower prices in general.
The conditions in rotary kilns, such as high temperature, the high speed of the gas stream, and the
long particle-storage period, guarantee that the use of alternative fuels is ecologically safe. The
energy-intensiveness of cement production processes and increasing fuel prices, combined with fuel
deficit, force the cement industry to search for technologies based on waste-derived and alternative
fuels (Mokrzycki and Uliasz-Bocheńczyk, 2003; Mokrzycki et al., 2003).
The use of fuels made from waste in cement plants results not only in financial benefits for the
industry, but also for society (Mokrzycki et al., 2003). The cement industry may give a significant
contribution to the resolution of a problem, which seriously affects most of the industrialized
countries, namely the continuous growth of wastes that have to be adequately disposed of, e.g.,
scrap tires.
Worldwide, almost one billion tires for passenger cars, utility vehicles, trucks, and off-road
vehicles are manufactured each year, and almost an equal number of tires is permanently removed
from vehicles and defined as waste. On average, approximately one scrap tire per person per year is
accumulated in industrialized countries. Over the years, new amounts are added to the billions of
tires already stored or buried in landfills, as well as at some illegal sites, warehouses, and other fields
around the world.
In the EU alone, approximately 3.5 million tones of passenger car, utility vehicle, and truck tires
become waste each year. Their use as an alternative fuel could provide 112 million GJ of energy and
save 18.5 million barrels of crude oil (ETRA, 2013).
486 B. NAKOMCIC-SMARAGDAKIS ET AL.
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

In Serbia considering that the average lifespan for car tires is about 8 years and that annual
production is approximately 1.1 million pieces or around 15,000–18,000 tons and with the additional
value of technical products from rubber industry production there is approximately 30,000 tons of
scrap tires annually. The use of tires as alternative fuels in Serbia could provide one million GJ of
energy and save 160 thousand barrels of crude oil (Djekic et al., 2010).
In fact, the European Directive (directive of the European Union, En 197/1) makes it possible to
use alternative fuels in the clinker kilns. Actually, due to very high temperatures reached (≈1400°C)
by clinker kiln, the cement industries provide a means to reuse both waste tires and oils, whose
utilization is recommended by the European Union (directive of the European Union, 91/156/CEE,
91/689/CEE, and 94/62) (Prisciandaro et al., 2003).
Utilizing tires as alternative fuel has the following advantages for the cement manufacturing
process:
(1) The cement burning process is a closed system where the dust removed from the exhaust gas
by an electrical precipitator is recycled into charge material. Thus, the ash in tires is not
discharged from the system. Moreover, sulfur contained in tires will be absorbed by the raw
materials of cement and will not create harmful sulphur oxides.
(2) The temperatures within the process will reach a maximum of 1800°C in the burning gas
and about 1500°C in the clinker. Therefore, tires fed to the kiln will burn completely within
a short time.
(3) Tire is composed of rubber, carbon-black, sulfur, and steel. Steel, which is not a combustible
component, will be oxidized and will be transformed into one of the cement components
(Nakajima and Matsuyuki, 1981).
Worn tires, although a particular residual material, are excellent sources of energy, especially
when used as secondary fuels. Tires can be completely destroyed in the rotary kiln due to the
characteristics of these devices that combine extremely high temperatures with an oxidizing atmo-
sphere and a residence time of material relatively long. The complete combustion prevents the
formation of soot or odors.
Tires are composed of about 88% of carbon and oxygen, which have a very low heating value
of about 32 MJ/kg, and burn quickly. The high calorific value of the tires contribute to lower
consumption of non-renewable fuels (coal and oil), thus saving natural resources (Lamas et al.,
2013).Buttheuseoftireasafuelislimitedtoamaximumof30%forcementindustrydueto
the presence of heavy metals in their composition, mainly zinc. This has the effect of lowering the
initial resistance, but ensures higher final strength of the cement (Bhatty, 1995; Pipilikaki et al.,
2005).
In this article, monitoring results of nitrogen and sulfur oxide emissions from cement kilns are
given, depending on the tires share in total amount of fuel. Research was carried out in the cement
industry in Serbia with a dry method of clinker production with tires heat ratio in fuel from 0
to 15%.
2. Dosage of scrap tires as a secondary fuel in cement production
Fuel dosage in rotary kilns with pre-heater is done through the main burner at the front of a rotary
kiln (primary dosage) and at the transition between pre-heater and rotary kiln (secondary dosage).
Primary dosage involves inserting fuel into the sintering zone through the main burner, and this
area is also called the primary combustion zone. For optimal adjustment of the flame from the
standpoint of using coal as a primary fuel and different requirements from the standpoint of raw
material quality, burners with adjustable flame are used. These burners have the option of separate
or simultaneous injection of fuel, such as pulverized coal; petroleum coke; fuel oil; natural gas; and
so-called alternative fuels, such as pulverized plastics, waste oil, etc.
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS 487
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

Secondary fuel dosage in a rotary kiln is implied to be fuel injection that is not done through the
main burner. A secondary dosage system is usually used for alternative fuel dosage, such as tires.
Tires are dosed into the flue gas chamber where flue gas temperatures are around 1000°C, and
material temperatures are up to 800°C. After insertion into the flue gas chamber, tires go to the
rotary kiln where they start to burn, and then carried with material leave to the zones with higher
temperatures where they are completely burned. Organic components are entirely burned in the
calcinations zone, i.e., in areas where the temperature of flue gases is between 1100 and 1200°C, and
for material around 900°C. Oxidation of inorganic components occurs in the transition and sinter
zone of the kiln. In these zones oxides are incorporated into the clinker structure.
Figure 1 shows the simplified scheme of rotary kiln with marked movement directions and
temperatures of materials and hot gases, and the place of introducing secondary fuel into the flue
gas chamber.
In Table 1 some basic technical parameters of rotary kilns for cement production are given.
Figure 1. Simplified scheme of rotary kiln with marked place for tire dosage. © Svetlana Pavić. Reproduced by permission of
Svetlana Pavić. Permission to reuse must be obtained from the rightsholder.
Table 1. Basic technical parameters of rotary kiln (Arhitekt AD, 2007).
Characteristic Unit Value
Nominal length m 60.0
Diameter of the combustion zone m 4.8
Diameter of the calcination zone m 4.8
Diameter at the junction with the flue gas chamber m 5.0
Slope % 3.5
Capacity t/dan 4,000
Installed operating power kW 2 × 450
Maximum rotation speed min
–1
4
Specific electricity consumption kW/t 3
© Svetlana Pavić. Reproduced by permission of Svetlana Pavić. Permission to reuse must be obtained from the rightsholder.
488 B. NAKOMCIC-SMARAGDAKIS ET AL.
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

3. Experiment description and selection of measuring points
It is foreseen that, during experimental study, dosage of tires is conducted by two trailer channels
with dual movable partitions. Movable partitions are placed one below the other on the same side of
the channel. They are opened and closed pneumatically by four cylinders. One connection channel is
for the whole, and the other one for shredded tires. Capacity of connection channels is 5 t/h of tires.
Measuring nitrogen and sulfur oxides emissions from a rotary kiln occurred throughout the trial
(limited) use of tires as secondary fuels in a cement factory, while referential measurement of
emission was conducted without the use of the tire. Position of measurement points was determined
in accordance with the standards and methods anticipated for this type of measurements and
working conditions in the facility, i.e., in accordance with ISO 9096:2003. Measurement points
were chosen so that they could realistically reflect the actual state of nitrogen and sulfur oxides
emissions in the air.
Measurement points for nitrogen and sulfur oxides emission measuring during the combustion of
coal, petroleum coke, and scrap tires in a rotary kiln are the following:
●Chimney of the kiln after bag filter (measuring point 1: MP1);
●Chimney after electrofilter of raw material drier (measuring point 2: MP2).
At the emitter (chimney) measuring point with circular cross-section, laminar air flow was
provided, which is in accordance with ISO 9096:2003. Key features of the bag filter after rotary
kiln and also emitter characteristics are shown in Table 2. The main characteristics of an electrofilter
of raw material drier and emitter are shown in Table 3.
Nitrogen and sulfur oxides emission measurement at point 1 was performed at the vertical section
of flue gas duct at a height of approximately 30 m, and emission measurements at point 2 were
carried out at the vertical section of flue gas duct at a height of approximately 42 m. At both
sampling points, nitrogen and sulfur emission measurements were conducted in accordance with
Table 2. Characteristics of rotary kiln’s bag filter and emitter (measuring point 1).
Bag filter
1. Filter type Bag
2. Ventilator type Radial
3. Number of chambers 10 (300 bags in every chamber)
4. Rotation speed (possibility of regulation) 740 min
–1
5. Under pressure Constant
6. Ventilator capacity 450,000 m
3
/h
Emitter (measuring point 1)
1. Emitter height 40.3 m
2. Diameter 4.002 m
© Svetlana Pavić. Reproduced by permission of Svetlana Pavić. Permission to reuse must be
obtained from the rightsholder.
Table 3. Characteristics of electrofilter of raw material drier and emitter (measuring point 2).
Electrofilter
1. Filter type Electro
2. Number of fields 4
3. Capacity 450,000 m
3
/h
4. Ventilator type Radial (M-02-01)
5. Ventilator capacity 430,000 m
3
/h
Emitter (measuring point 2)
1. Emitter height 50.9 m
2. Diameter 3.2 m
© Svetlana Pavić. Reproduced by permission of Svetlana Pavić. Permission to reuse must be
obtained from the rightsholder.
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS 489
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

ISO 9096:2003. The coal sampling point is not shown because the standard measuring point and
procedure regularly conducted in the cement factory were used.
4. Results and discussion
During monitoring of nitrogen and sulfur oxides emission from the cement kiln, coal and petroleum
coke were used as primary fuel, and whole or shredded tires as secondary fuel. Lower heating value
of coal was 26.5 MJ/kg and 31.9 MJ/kg for petroleum coke, while its value for scrap tires was around
27 MJ/kg. Coal and petroleum coke consumption varied depending on the heat ratio of scrap tires.
With the increase of heat ratio of tires, proportionally decreased the required amount of coal and
petroleum coke.
Relevant parameters, depending on the heat ratio of scrap tires, are shown in Table 4 and
Figure 2, as well as concentrations and mass flows of nitrogen and sulfur oxides measured after
bag filter (MP1), i.e., electrofilter of raw material drier (MP2) of cement production rotary kiln.
According to Ali et al. (2011), in the cement industry the typical values for NOx concentration is
<200–3,000 mg/Nm
3
and for SO
2
concentration is <10–3,500 mg/Nm
3
.
A cement production rotary kiln, as well as devices for reducing emissions, were not specifically
prepared for the research, i.e., they were in the usual operating mode. The choice of plant load was
done so that it could realistically reflect the actual state of nitrogen and sulfur oxides emission.
During experimental research, it was observed that nitrogen and sulfur oxides emissions from the
cement production kiln mostly depends on the composition of raw material mixture; also, it depends
to a considerable extent on the composition of the fuel, and almost does not depend on the fuel
dosage method.
Table 4. Relevant parameters values for MP1 and MP2, depending on the heat ratio of scrap tires.
Measured Quantity Unit Measured Value
Heat ratio of scrap tires % 0.0 3.3 6.0 9.9 15.3
MP1 Volume fraction of O
2
% 11.88 12.53 11.60 11.65 11.92
Volume fraction of CO
2
% 14.64 12.72 14.89 14.04 13.84
Gases volume flow m
3
/h 438,773 436,938 427,450 429,923 446,205
Gas temperature °C 140 166 140 146 140
MP2 Volume fraction of O
2
% 12.11 12.30 12.66 12.81 12.74
Volume fraction of CO
2
% 13.88 12.83 12.93 12.07 12.67
Gases volume flow m
3
/h 235,016 202,880 253,222 240,725 236,352
Gas temperature °C 89.5 87.9 89.3 89.7 88.6
Figure 2. Influence of heat ratio of scrap tires on the concentration (a) and mass flow (b) of nitrogen and sulfur oxides.
490 B. NAKOMCIC-SMARAGDAKIS ET AL.
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

Experimental studies have shown that nitrogen oxides form during fuel combustion (coal,
petroleum coke, scrap tires) partially as a consequence of reaction of oxygen and nitrogen in the
air at high temperatures in a rotary kiln, and partially as a result of oxidation of nitrogen compounds
in the fuel. Amount of formed NOx is influenced by several factors, such as temperature of
combustion, flow velocity in combustion space, combustion space design, burner design, fuel
composition, ratio of fuel and air dosage, heat removal rate from combustion space, etc. (Dvořák
et al., 2010). During experimental tests, content of secondary fuels (scrap tires) was increased, and
primary fuels (coal, petroleum coke) were decreased, while other process parameters have not been
changed significantly. Thus, nitrogen oxides emission from a cement production kiln depended on
the content of nitrogen compounds in the used fuel. Since the nitrogen content in scrap tires is lower
than in coal and petroleum coke, the assumption is that nitrogen oxides emission is primarily
influenced by the quantity of scrap tires in the fuel mixture. Although with the increase of tires’share
in total fuel quantity, at some point there is a reduction of NOx emissions; it cannot be concluded
that there is a direct dependence, because with 10–15% of tires content NOx emissions is increasing
but still it stays below law-imposed limits.
Experimental studies also show that during the cement clinker production process release of
sulfur dioxide (SO
2
) depends on sulfur content in organic substance and pyrite present in the raw
material mixture, while scrap tires share in fuel mixture and fuel dosage method (primary or
secondary) had no significant impact on SO
2
emission. SO
2
emission did not significantly depend
on the used fuel type, because during experimental studies the difference between primary and
secondary fuel sulfur content was almost negligible. Raw material mixture content had the greatest
impact on SO
2
concentration in flue gases. However, after conducted research there could not be
defined a specific dependence between raw material mixture content and SO
2
emission from cement
production kiln. For further study of this dependence, there is a need to monitor SO
2
emission from
the rotary kiln for different sulfur content in raw material mixture, with other process parameters
unchanged.
In the literature exists different results for NOx and SO
2
emissions from the cement industry.
Prisciandaro et al. (2003) analyzed the emissions from an Italian cement plant using petroleum coke
and less than 20% tires. Through statistical analysis, the study asserted that, as compared with using
100% petroleum coke, the combustion of tires with petroleum coke in cement kilns increases SO
2
and NOx emissions. The study found that the increase of NOx emissions could be linked to the
burning conditions of the kiln, and in particular to excess air. Increased emissions of SO
2
are
supposedly caused by the incomplete combustion of tires, even though the amount of sulfur in the
mix of petroleum coke and tires is lower than for petroleum coke alone.
Carrasco et al. (2002) studied a Canadian cement factory that used coal as well as a combination
of coal and scrap tires. That study found a decrease in NOx emissions but an increase in SO
2
and
particulate emissions. They did not cite the percentage of scrap tires used as fuel; however, they
mentioned that the combustion efficiency was one of the main causes of pollutant emissions.
The UK Environment Agency (2008) conducted a study on a cement manufacturing plant in
Dunbar (using 25% tires), which showed an impact reduction, calculated through an environmental
quotient, for NOx. For SO
2
and particulate emissions, the situation was uncertain and case specific,
as findings showed both increases and decreases. The report suggested that this was due to the
pyritic sulfur content of raw materials, which has a substantial influence on emissions. The report
also cited the same behavior in four other UK cement factories.
A U.S. Environmental Protection Agency report (2006) stated that NOx emissions depend mainly
on the combustion process, while SO
2
emissions depend on the sulfur content of the fuel. The report
found that, although the use of tire-derived fuel did not decrease NOx emissions, it did not provide
further explanation about the methodology of the research. Another U.S. Environmental Protection
Agency report (2008), however, found that the use of scrap tires in cement kilns decreases NOx
emissions.
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS 491
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

An International Energy Agency report (2009) stated that burning tire-derived fuel in cement
kilns, instead of fossil fuels, decreased both NOx and SO
2
emissions but the report did not provide
additional insights into this finding.
A LaFarge document (2003) contained a case study about the use of scrap tires in cement kilns. In
that case, a cement plant in Atlanta that used 20% scrap tires as fuel decreased NOx emissions
by 4.6%.
Two Portland Cement Association reports (2008,2009) found that nitrogen oxide, sulfur oxide,
and particulate emissions were lower when scrap tires substituted a portion of the fossil fuels. They
also found no statistically significant differences in those emissions.
5. Conclusions
Characteristics of the cement production process presented in this article show that this is an
environmentally acceptable way of disposing of scrap tires, either whole, shredded, or granulated.
Besides the fact that use of scrap tires as an alternative fuel in the cement industry is environmentally
friendly, it is also energy and economically justified.
Dry method technology of clinker roasting in a rotary kiln with a multilevel preheater and
precalcinator is the best available technique in cement production.
Nitrogen and sulfur oxide emissions measurement was carried out for different shares of scrap
tires in fuel, and it was done after the bag filter, as well as after the electrofilter of raw material drier
of cement production kiln. The measurements have shown that the nitrogen oxides emissions are
higher at the chimney after electrofilter of a raw material drier, and that sulfur oxides emissions are
higher at the kiln chimney after the bag filter. The mass flow of nitrogen oxides and sulfur is higher
through the kiln chimney after the bag filter, than through the chimney after electrofilter of raw
material drier.
According to the experimental results, influence of heat ratio of scrap tires on the concentration
and mass flow of nitrogen and sulfur oxides have shown that NOx and SO
2
emissions were in the
case of tires slightly decreased, in some cases were incremented, but remaining always below the
local law imposed limits and it is in accordance with the European Waste Incineration Directive and
the Integrated Pollution Prevention and Control Directive.
Differing results exist for SO
2
and NOx emissions when partial replacement of primary fuel with
scrap tires in the cement industry is in place, suggesting that the issues are case specific and it has to
be further researched.
Funding
This article is partly financed within III-46009, III-42004, III-42006, and No. 69-00-102/210-02 Projects of the
Ministry of Education and Science of Republic of Serbia.
References
Albino, V., Dangelico, R. M., Natalicchio, A., and Yazan, D. M. 2011. Alternative energy sources in cement manu-
facturing—A systematic review of the body of knowledge. Department of Mechanical and Management Engineering,
Politecnico di Bari, Italy.
Ali, M. B., Saidur, R., and Hossain, M. S. 2011. A review on emission analysis in cement industries. Renewable
Sustainable Energy Rev. 15:2252–2261.
Bhatty, J. I. 1995. Role of minor elements in cement manufacture and use. Research and development bulletin RD109T.
Skokie, IL: Portland Cement Association.
Carrasco, F., Bredin, N., and Heitz, M. 2002. Gaseous contaminant emissions as affected by burning scrap tires in
cement manufacturing. J. Environ. Qual. 31:1484–1490.
Djekic, P., Temeljkovski, D., and Stojance, N. 2010. Selection of an optimal process for scrap tires recycling. Research
Des. Ind. 8:65–72 (in Serbian).
492 B. NAKOMCIC-SMARAGDAKIS ET AL.
Downloaded by [Zoran Cepic] at 01:04 10 February 2016

Dvořák, R., Chlápek, P., Jecha, D., Puchýř, R., and Stehlík, P. 2010. New approach to common removal of dioxins and
NOx as a contribution to environmental protection. J. Cleaner Prod. 18:881–888.
ETRA. 2013. European Tire Recycling Association. Available at: http://www.etra-eu.org/.
International Energy Agency. 2009. Cement Technology Roadmap 2009. Available at: https://www.iea.org/publications/
freepublications/publication/Cement.pdf.
Jankovic, A., Valery, W., and Davis, E. 2004. Cement grinding optimisation. Min. Eng. 17:1075–1081.
LaFarge. 2003. LaFarge and the Environment 2003. Available at: http://www.lafarge.com/sites/default/files/import/
publication/09212004-publication_sustainability-Environment_brochure_2003-uk.pdf.
Lamas, W. Q., Palau, J. C. F., and Camargo, J. R. 2013. Waste materials co-processing in cement industry: Ecological
efficiency of waste reuse. Renewable Sustainable Energy Rev. 19:200–207
Madlool, N. A., Saidur, R., Hossain, M. S., and Rahim, N. A. 2011. A critical review on energy use and savings in the
cement industries. Renewable Sustainable Energy Rev. 15:2042–2060.
Madlool, N. A., Saidur, R., Rahim, N. A., and Kamalisarvestani, M. 2013. An overview of energy savings measures for
cement industries. Renewable Sustainable Energy Rev. 19:18–29.
Mokrzycki, E., and Uliasz-Bocheńczyk, A. 2003. Alternative fuels for the cement industry. Appl. Energy 74:95–100.
Mokrzycki, E., Uliasz-Bocheńczyk, A., and Sarna, M. 2003. Use of alternative fuels in the Polish cement industry. Appl.
Energy 74:101–111.
Nakajima, Y., and Matsuyuki, M. 1981. Utilization of waste tires as fuel for cement production. Conserv. Recycl. 4:145–
152.
Nielsen, A. R. 2012. Combustion of large solid fuels in cement rotary kilns. Ph.D. Thesis, Department of Chemical and
Biochemical Engineering Technical University of Denmark, Kongens Lyngby, Denmark.
Oggioni, G., Riccardi, R., and Toninelli, R. 2011. Eco-efficiency of the world cement industry: A data envelopment
analysis. Energy Pol. 39:2842–2854.
Pavić, S. 2011. Comparative analysis of the flue gases composition during the transition from fossil to alternative fuels
in Lafarge Beocin cement factory. MSc Thesis, University of Novi Sad, Faculty of Technical Sciences. Novi Sad,
Serbia. [in Serbian]
Pipilikaki, P., Katsioti, M., Papageorgiou, D., Fragoulis, D., and Chaniotakis, E. 2005. Use of tire derived fuel in clinker
burning. Cement Concrete Compos. 27:843–847.
Prisciandaro, M., Mazziotti, G., and Veglió, F. 2003. Effect of burning supplementary waste fuels on the pollutant
emissions by cement plants: A statistical analysis of process data. Resourc. Conserv. Recycl. 39:161–184.
Portland Cement Association. 2008. Tire-derived Fuels. Available at: http://cement.org/Briefingkit/pdf_files/
TDFBrochure.pdf.
Portland Cement Association. 2009. Report On Sustainable Manufacturing. Available at: http://cement.org/smre
port09/images/shared_images/sustainreport08.pdf.
UK Environment Agency. 2008. The Use of Substitute Fuels in the UK Cement and Lime Industry. Available at: https://
www.gov.uk/government/uploads/system/uploads/attachment_data/file/291698/scho1207bnna-e-e.pdf.
U.S. Environmental Protection Agency. 2006. Controlling Fine Particulate Matter Under the Clean Air Act: A Menu of
Options. Available at: http://www.4cleanair.org/PM25Menu-Final.pdf.
U.S. Environmental Protection Agency. 2008. Trends in Beneficial Use of Alternative Fuels and Raw Materials –
Cement Sector. Available at: http://archive.epa.gov/sectors/web/pdf/cement-sector-report.pdf.
Zabaniotou, A., Lagoudakis, J., Toumanidou, E., and Stavropoulos, G. 2002. Energetic utilization of used tires. Energy
Sources Part A 24:843–854.
ENERGY SOURCES, PART A: RECOVERY, UTILIZATION, AND ENVIRONMENTAL EFFECTS 493
Downloaded by [Zoran Cepic] at 01:04 10 February 2016