Environmental Engineering and Management Journal [619163]

Environmental Engineering and Management Journal
July 2014, Vol.13, No. 7, 1657-1663
http://omicron.ch.tuiasi.ro/EEMJ/

“Gheorghe Asachi” Technical University of Iasi, Romania

MONITORING EMISSIONS FROM LARGE COMBUSTION PLANTS

Mirela Panainte, Marius St ănilă, Emilian Mo șneguțu, Oana Irimia, Doina Cap șa,
Florin Nedeff, Claudia Tomozei, Ion Joi ța, Gabriela Teliba șa

"Vasile Alecsandri" University of Bacau, Romania, 600115, Bacau, Romania

Abstract
The most important aspect of the national environmental policy co ncerns air pollutant emission de crease. The studies led in ord er
to identify the atmospheric pollution sources have revealed that the energy sector is one of the biggest pollutants in the econ omy.
Given the negative impact of the polluta nt emissions on the environment and the po ssibility of closing the large combustion
plants in case necessary measures to comp ly with the legal regulations in the field are not taken will significantly reduce the
amount of air pollutants from these installa tions. This paper presents a case study re garding the monitoring of emissions from the
large combustion plants on the platfo rm of S.C. CET S.A. in Bacau.

Key words: combustion plant, em ission limit value, fuel , monitoring, reduction

Received: March, 2014; R evised final: July, 2014; Accepted: July, 2014

 Author to whom all correspondence should be a ddressed: e-mail: [anonimizat], telephone:+[anonimizat] 1. Introduction

Energy saving together with the decrease of
the greenhouse gas emissions and global warming
attenuation have become problems with major
technological, social and political impacts (Friedler, 2010). Since 1970, en ergy efficiency and
conservation have become key components of energy
security approach. They were also considered effective ways to cut down the emissions of
greenhouse gases from burning of fossil fuels (Neelis
et al., 2007).
Electricity production in the world is expected
to exceed over the next 25 years, mainly due to the
demand of emerging economies. In this context, the
charcoal will likely remain one of the most important
energy sources, which will entail significant amounts of pollutant emissions unless measures to reduce
them are being taken (Yeh and Rubin, 2007).
Researches in the Chines e energy sector have
shown that the use of ecological processes together
with the emission of control technologies could lead
to the decrease of SO
2 emissions with about 67% until 2020 compared with the levels in 1995. Instead,
an increase of approximately 180% towards the
levels in 1995 could be recorded unless control devices will be installed and measures to diminish
the emissions from industrial processes will not be
taken. In addition, NO
x emissions are expected to
increase with approximately 150% over the levels in
1995, exceeding the emissions from North America
and Europe (Kanako, 2011; Streets et al., 2000).
Targets regarding pollutant emissions
decrease can be achieved by implementing specific
climate policies, in particular significant economic sanctions which could stimulate the rehabilitation of
a large number of charcoal power plants (Stigson et
al., 2009). An Eurobarometer report (EC, 2013)
shows that a majority of the Europeans of 56%
believes that, air quality deteriorated in the last 10 years. Approximately four out of five participants
(79%) in the study believe that the European Union
should propose additional measures to solve the problem of air pollution (EC, 2013). Regarding the
most effective way to fight against air pollution, 43%
of respondents suggested tighter controls of the

Panainte et al./Environmental E ngineering and Management Journal 13 (2014), 7, 1657-1663

1658 emissions from industry and energy production. The
sources of emissions with the greatest influence on
air pollution are: vehicles (96%), industry (92%) and
international transport (86%) (EC, 2005).
In order to reduce the impact produced by
climate change, governments should implement
adequate policies and regulations to improve energy efficiency in industry. Particularly, this should
address large combustion plants, which are the main
suppliers of heat and hot water for urban consumers
but also the main sources of air pollution due to fossil
fuels (charcoal, petroleum) they use (Kondili et al., 2005; Rao et. al, 2002).
Taking into consideration the negative impact
of the pollutant emissions upon the environment and
the possibility of closing the large combustion plants
within a transition period in the view of greenhouse
gases emissions reduction, their rehabilitation is top
priority for the economic agents which use these
types of installations (Kondili et al., 2005; Rao et al.,
2002). The control of emissions from large
combustion plants – those whose rated thermal input
is equal to or higher than 50 MW
t – plays an
important role in the EU's efforts to stop
acidification, eutrophication and greenhouse gas
emissions, as part of the overall strategy to reduce
environmental pollution.
The EC Directive (2001) (the LCP Directive)
addresses the reducing of the emissions of acidifying
pollutants, powders and ozone precursors, as its
overall objective. The Directive encourages the
production of combined thermal energy and
electricity and sets specifi c emission limit values for
sulphur dioxide, nitrogen oxides and dust. The
requirements of EC Directive (2001) were transposed
into the national legislation by a Governmental
Decision (GD 541, 2003).
The reduction of pollution produced by large
combustion plants can be the best achieved by their rehabilitation. Some rehabilitation techniques include
(Cristóbal et al., 2012; EC, 2005; Kanako, 2011;
Măcărescu et. al, 2010; St ănilă et al., 2013):
‐ implementation of best available techniques for
reducing pollutant emissions (investments in plant
flue gas desulphurization, burners with NO
x slow
content, filters for large combustion plants);
‐ good maintenance and equipment upgrading for
environmental protection;
‐ reuse of materials and heat resulted from the
production process;
‐ improvement of process co ntrol for an efficient
use of raw materials, energy as well as for productivity growth;
‐ reuse and recycling of products and materials;
‐ CO
2 capture and storage;
‐ ensuring the access to the implementation of
effective technologies and equipment (including the
achievement of technology transfer) and developing the capacity of energy production.
This paper analyses the results of SO
2 and
NOx emissions monitoring from IMA 1 – S.C. CET S.A. combustion plant in Bacau city, Romania. 2. Measurement technique

District heating power-station type I has the
mission to provide Bacau ci ty with thermal energy
according to the required parameters, having a rated
thermal input of 419 MW
t and two large combustion
plants, including ancillary installations:
‐ IMA 1, with a thermal power of 343 MW t is built
up of an energy boiler type CRG 1870 which can
produce a steam flow of 420 t/h. The steam produced by the boiler is used to generate electricity and
cogenerate heat by its expansion in a turbine DSL 50
type. The main fuel is lignite with addition of natural gas or fuel oil. The energy input of the boiler given
by the natural gas or the fuel oil can vary from 10%
(minimum required to ensure the stability of the
combustion process in the furnace) to 100%,
depending on the availability of the supply system with solid fuel;
‐ IMA 2, with a thermal power of 76.5 MW
t is
composed by the indust rial steam boiler (CAI)
BABCOCK type, which can produce a steam flow of
100 t/h. The boiler uses natural gas or fuel oil. The
steam produced is delivered to industrial consumers or is used to heat the water which circulates through
the district heating networks. The industrial steam
boiler with a capacity of 100 t/h constitutes a reserve for the secure supply with thermal energy in Bacau
city and works on the following conditions only:
‐ during winter, when the boiler of 420 t/h
capacity is unavailable;
‐ during summer, when the boiler of 100 Gcal/h
type CAF is unavailable.
The residual gases from the two combustion
plants (which operate alternatively) are released
through a gas chimney of 220 meters height. This chimney has the role of ensuring the gases dispersion
into the atmosphere and was designed so as the to not
attend the permissible limit values for the concentrations of pollutants in the atmosphere.
The gases resulting from the burning
processes of coal (lignite) in the boiler with a capacity of 420 t/h contain a large amount of ash (70
g/Nm
3). To clean the gases of this pollutant, the
energy system was designed with a retention equipment of the solid powder s that are in suspension
in the flue gas discharged through the chimney.
S.C. CET S.A. Bacau benefits of a compliance
period according to GD 440 (2010), (Tables 1 and 2)
stipulated by EC Directive (2001) addressing the
limitation of emissions of certain pollutants into the
air from large combustion plants, from the
Commitments Resulting from the Negotiations of Chapter 22-The Environment (AM, 2006). Up to the
complying with these regulations, the the plant
exploitation is allowed provided that the annual emission limits negotiated are fulfilled (AM, 2006).
According to the integrated environmental
permit (AM, 2006), the monitoring of the SO
2 and
NO x emissions for or the two plants is performed
three times per week. The resulting values of the
measurements are compared with the emission limit

Monitoring emissions from large combustion plants

1659values imposed by the environmental authorization,
respectively the standards imposed by GD 440,
(2010), The data of the measurements performed
during November 2010 and March 2011 (the period of time when the boiler (IMA 1) operates in normal
regime) are analyzed in th is paper with the aim to
determine the SO
2 and NO x emission levels. The exhaust gas analyzer DELTA 2000CD-IV
was used to determine the gaseous emissions. The
placement of the measurement points for the
collection of the pollutants emitted from the CRG 1870 (IMA 1) type of boiler are shown in Figs. 1 and
2.

Table 1. Emission limits for sulphur dioxide (AM, 2006)

Emission limits (tons/year)
No. Combustion plant Boiler Thermal
power
MW t 2007 2008 2009 2010 2011 2012 2013
CET Bacau no.1
(IMA 1) Steam boiler CRG
1870 (420 t/h) 343 8005 8005 8005 8005 8005 1281 1281
1
CET Bacau no.2
(IMA 2) Steam boiler
Babcock (100 t/h) 76.5 127 127 127 127 127 127 127

Table 2. Emission limits for nitrogen oxides (AM, 2006)

Emission ceilings (tons/year)
No. Combustion plant Boiler Thermal
power
MW t 2007 2008 2009 2010 2011 2012 2013
CET Bacau no.1
(IMA 1) Steam boiler CRG
1870 (420 t/h) 343 1057 1057 1057 1057 1057 1057 1057
1 CET Bacau no.2
(IMA 2) Steam boiler
Babcock (100 t/h) 76.5 42 42 42 42 42 42 42

Fig. 1. The location scheme of the equi pment used to harvest the polluta nts emitted by the CRG boiler 1870

Fig. 2. Division through the flue channels

Panainte et al./Environmental E ngineering and Management Journal 13 (2014), 7, 1657-1663

1660
3. Research results

According to the requirements of the
integrated environmental permit and the GD 440
(2010) upon the functioning of large combustion
plants such as those from S.C. CET S.A. Bacau which use different fuels, the emission limit
valuesare those from Table 3.

Table 3. Thresholds of gaseous emissions from large
combustion plants IMA 1 and 2 from S.C CET S. A. Bacau

Emission limit values* (mg/Nm3)**
Pollutant Stoves
fueled by
solid fuel
(6%
++++++ O2) Stoves
fueled by
liquid fuel
(3% O 2) Stoves fueled
by gaseous fuel
(3% O 2)
IMA 1 – 343 MW t
SO 2 1028 1420 35
NO x 600 450 300
IMA 2 – 76.5 MW t
SO 2 – 1700 35
NO x – 450 300
* – limit value of 100 mg/Nm3 is applied when fuel oil has a higher
gas content of 0.06%
** according to GD 440 (2010)

Since the installation IMA 1 works with
combined fuels, the emission limit values shall be calculated by Eq. (1), (GD 440, 2010).



i ii ii
PciQPciQ VLEVLE (1)

where: VLE is the emission limit value for a
particular pollutant, in the case of mixed furnace;
VLE i – emission limit value for the pollutant when
use fuel "i"; Qi – fuel flow „i”; Pci i – power heating
value of fuel „i”.
The results of the measurements performed in
November 2010 show that the emission values for
SO 2 and NO x fall within the limit values calculated
according to GD 440 (2010). As the graphical representation in Fig. 3
shows, the measured values for SO 2 emissions varied
between 225 mg/Nm3 ÷ 580 mg/Nm3, while the
maximum value was recorded on November 24th,
2010. The measured values of emission limit values
calculated according to Gov. Decision 440/2010 ranged between 805 mg/Nm
3 ÷ 913 mg/Nm3,
according the amount of fuel and its calorific value.
The analysis of NO x emissions measurements
showed thet the measured values varied between 116
mg/Nm3 ÷ 133 mg /Nm3, the maximum value being
recorded on November 19, 2010 respectively 133
mg/Nm3 (Fig. 4). The measured values of emission
limit values calculated acc ording to GD 440 (2010)
ranged between 533 mg/Nm3 ÷ 565 mg/Nm3. The
recorded values were influenced by the lower heating
value of the fuel and not by the quantity of fuel burned.
The emission of SO
2 varied between 415
mg/Nm3 ÷ 666 mg/Nm3 in December 2010, while the
maximum value was recorded on 21 November 2010.
These emissions are combined with a large amount
of fuel burned with a lower calorific value. The measured emission values ar e in accordance with the
emission limit values calculated to GD 440 (2010),
ranging between 752 mg/Nm
3 ÷ 886 mg/Nm3 (Fig.
5). The same situation can be observed for NO x
whose measured values (103 mg/Nm3 ÷ 119
mg/Nm3) fall with the emission limit values
calculated according to GD 440 (2010), being in the
interval 517 mg/Nm3 ÷ 557 mg/Nm3 (Fig. 6).
The measurements perf ormed in January 2011
showed that SO 2 emission levels (480 mg/Nm3 ÷ 735
mg/Nm3) were also in the in terval allowed according
to GD 440 (2010), respectively 870÷ 957 mg/Nm3.
The emission levels were influenced by the lower
calorific value of the fu el burned. The maximum
measured value was recorded on 5th of January 2011,
when a larger amount of coal with low calorific value
was used as fuel (Fig. 7). The NO x emissions
measured values fall in the range 84 ÷ 172 mg/Nm3,
being in the emission limit values according to GD
440 (2010) of 552 ÷ 579 mg/Nm3 (Fig. 8).

Fig. 3. Variation emissions of SO 2 discharged into the
atmosphere in November 2010
Fig. 4. Variation emissions of NO x discharged into the
atmosphere in November 2010

Monitoring emissions from large combustion plants

1661

Fig. 5. Variation emissions of SO 2 discharged into the
atmosphere in December 201
Fig. 6. Variation emissions of NO x discharged into the
atmosphere in December 2010

Fig. 7. Variation emissions of SO 2 discharged into the
atmosphere in January 2011
Fig. 8. Variation emissions of NO x discharged into the
atmosphere in January 2011

Some measurements performed in February
2011 show an exceede d emission limit value
calculated for SO 2 (771 mg/Nm3 ÷ 973mg/Nm3), in
particular on February 26th, 2011, when a value of
846 mg/Nm3 SO 2 has been recorded for emissions
due to the use of a lower calorific fuel (Fig. 9). NO x
measured emissions values fall in the range 84÷ 117
mg/Nm3, all within the emission limit values allowed
by GD 440 (2010), of 522 ÷ 583mg/Nm3. The
maximum value was found on February 26th, 2011
(Fig. 10). In March 2011, the recorded values of SO 2
emissions, namely 535 ÷ 723mg/Nm3 fall within the
emission limit values according to GD 440 (2010), (696 mg/Nm
3 ÷ 954 mg/Nm3). The maximum
measured value for SO 2, respectively 723mg/Nm3 was
recorded on March 18, 2011 (Fig. 11). The the measured values of NO
x emissions, (92 mg/Nm3 ÷
138 mg/Nm3) were under emission limit values (500
÷ 578 mg/Nm3). The maximum value recorded
corresponds to the date of March 4th, 2011 (Fig. 12).

Fig. 9. Variation emissions of SO 2 discharged into the
atmosphere in February 2011
Fig. 10. Variation emissions of NO x discharged into the
atmosphere in February 2011

Panainte et al./Environmental E ngineering and Management Journal 13 (2014), 7, 1657-1663

1662

Fig. 11. Variation emissions of SO 2 discharged into the
atmosphere in March 201
Fig. 12. Variation emissions of NO x discharged into the
atmosphere in March 2011

4. Conclusions

Because S.C. CET S.A. Bacau, Romania
received a transitional period for complying with
environmental norms concerning atmospheric emissions, its functioning is permitted provided that
the plant complies with the negotiated annual
emission limits.
Measurements of SO
2 and NO x emissions
were carried out during November 2010 – March
2011, given the fact that the large burning facility worked relatively constant, without major changes in
load or fuel quality.
The resulted data emphasizes that:
‐ SO
2 emissions usually fall within the limit values
imposed by Romanian regulations, excepting that
recorded on February 26th, 2011 of 846 mg/Nm3 SO 2
which exceeds the maximum allowed value of 776
mg/Nm3, due to lower calorific fuel;
‐ the measured levels of NO x emissions were found
within the accepted limit va lues according Romanian
regulations for the entire monitoring period
(November 2010 – March 2011);
In order to comply with the requests viewing
the emission limit values and with the annual
emission limits, the company's management focused on the implementation of measures acccording to the
best available techniques in the field (BAT), as
follows:
‐ the reduction of NO
X emissions by primary
measures and the use of low NO x burners;
‐ putting into action of the group cogeneration of
gas-steam combined cycle of 14 MW t.
Acknowledgements
The work has been funded by contract research no. 6/2010
ʺResearch on monitoring th e exhaust emissions from
combustion plants from platform S.C. CET S.A. Bacau, as
well as using the measuring device DELTA 2000, the
purpose of acquiring of data on continuous flow from IMA
I and 2".

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