Air Pollutant Emissions and their Control – with the focus on waste incineration facilities –

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Dorfstraße 51

D-16816 Nietwerder-Neuruppin

Tel. +49.3391-45.45-0 • Fax +49.3391-45.45-10 E-Mail: tkverlag@vivis.de

Order now: www. .de

TK Verlag Karl Thomé-Kozmiensky

– with the focus on waste incineration facilities –

This comprehensive text and practical handbook thoroughly presents the control of air pollutant emissions from combustion processes focusing on waste incinerators. Special characteristics are emphasised and the differences to emission control from combustion processes with other fuels are explained.

The author illustrates the origin and effects of air pollutants from incineration processes, the mechanics of their appearance in the incineration process, primary and secondary measures for their reduction, processes of measuring the emissions as well as the methods of disposing the residues. In particular, the pros and cons of procedual steps and their appropriate combination under various conditions are emphasised.

Moreover, the book contains information and analyses of the emissions situation, the consumption of operating materials and of backlog quantities as well as of the cost structure of waste incinerators with regard to their applied control system.

Furthermore, the author explicates the contemporary legal, scientific and technological developments and their influence on air pollutant emission control. An evaluation of the status quo of air pollutant control at waste incinerators in Germany, practical examples about possible combinations and typical performance data complete the content.

Accordingly, this book is a guideline for planing a reasonable overall concept of an air pollutant control that takes the location and the segregation tasks into consideration. This book is addressed to students, decision makers, planners and the operating practicioners if for example the construction of a new system or the implementation of improvement measures have to be conducted.

Released: August 2017 120.00 EUR

Emissions and Emission Monitoring

340 Fixed mirror

Focussing mirror Beam splitter

with compensator

Moving mirror

Light source Gas sample Gas sample Collimator

Detector Sample cell

Figure 242: Measurement principle of an FTIR multi-component spectrometer with a Michelson interferometer setup

Source:

TÜV Süd Industrie Service GmbH, UBA-Texte 05/08, adapted

splitter where they are brought together to interfere with each another in intensity as they recombine. Depending on the mirror displacement, the interference may be constructive (increasing) or destructive (decreasing). When using polychromatic light, the interference occurs for each wave length so that the interference intensities of the individual wave lengths superpose one another [369].

of the target component and are directed by a focusing mirror to an infrared detector is computed from the recorded interferogram (intensity at detector as a function of mirror displacement) by mathematical Fourier transformation. For quantitative evaluation, the calculated infrared spectrum is compared with a reference spectrum [380].

An alternative to the Michelson interferometer is the vibration-insensitive RockSolid arrangement [356].

9.2.3.3.2 Multi-component measurement by non-dispersive infrared spectroscopy Non-dispersive infrared (NDIR) spectroscopy is based on the absorption of an infrared spectrum wavelength that is unique to the gaseous component to be detected.

In contrast with dispersive infrared spectroscopy, non-dispersive methods do not spectroscopy is applicable to multi-component analysis, i.e. the simultaneous analysis of several emission parameters, and is frequently also used for raw gas measurements.

detector Light source Sample cell Calibration filter

Lens Detector

Filter wheels Chopper

Figure 243: Measurement principle of a multi-component NDIR spectrometer with heated sample gas cell Source: Boneß, M.: Messsysteme und Analysatoren zur kontinuierlichen Prozesskontrolle und Emissionsüberwachung in und Betrieb von Anlagen, Vol. 1, pp. 527–538. Neuruppin: TK Verlag, 2010 As infrared detectors can only detect changes in the infrared radiation, they require a modulated (pulsed) infrared source that is temporarily interrupted by a mechanical

component and selects the spectral region of its absorption band. If several gas components are to be analysed, chopper wheels covering several infrared spectral regions to calculate the gas concentration, which requires a concentration-independent reference signal for comparison. For this purpose, NDIR analysers may be equipped with absorption band of the analysed component (bi-frequency technique). Alternatively,

.

Continuous Emission Monitoring

Also available in German!

50.00 EUR

Author: Margit Löschau • Publisher: TK Verlag Karl Thomé-Kozmiensky • Hardcover: about 480 pages, numerous coloured images

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Flue Gas Treatment

SNCR Technology

to Meet Challenging NO

_x

Reduction Requirements

Wolfgang Schüttenhelm and Philip Reynolds

1. State-of-the-art ...392

2. Challenging NO_x reduction ...394

3. Dual injection SNCR technology ...397

4. Improved monitoring and control ...400

4.1. Plausibility check ...401

4.2. Online check of the measured value drift ...401

4.3. Online calorific value ...401

4.4. Fractionation ...402

5. Profitability...402

6. Flexibility or simplification? ...403

7. Conclusion ...404

8. Literature ...405

NO_x reduction by means of SNCR-Technology is continuously developing to increase its performance potential. This ongoing development is based on more and more sophisticated control concepts, modified hardware and software as well as improved designs. Consequently, increased requirements in respect to higher levels of process safety, increased reliability of mechanical components, better efficiency of the injected reduction agents as well as higher degree of automation are achieved.

This paper addresses ERC’s most recent developments of the SNCR technology.

Today, this well-proven denitrification process is able to meet even very challenging requirements due to the combination of new control concepts with new and improved injection processes.

As already described in [1] new emission limits for NO_x and NH₃ are set in the German 17. BImSchV for waste-to-energy plants. In detail, daily average limits of 150 mg/Nm³ NO_x and 10 mg/Nm³ NH₃ at actual O₂ content are to be met for new and existing waste- to-energy units of more than > 50 MW thermal capacity from 01.01.2019.

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Many existing units are equipped with SNCR meeting the more moderate existing limits of today. These units have been able to safely comply and these more relaxed requirements could be fulfilled with the typical deviating combustion conditions of waste-to-energy plants. However, the new more stringent limits are requesting much more flexible SNCR solutions to provide the same safe operation. Thus, adaptions, modifications and upgrades are necessary for many units in order to cover the whole operational range of fuels and loads. The set of measures usually has to be determined for each individual plant due to different site conditions, firing systems as well as local requirements and factors. Potential measures, impacts and concepts will be presented to show efficient and high performance modernization solutions of SNCR installations.

Of course, modernization requires new investments. However, such measures are also increasing the efficient use of the reduction agent which at least is going to compensate for a part of the spent costs. Besides, longer boiler running times and/or load increases can be a part of the measures which might even turn the expenses into a benefit after a short time period.

1. State-of-the-art

The NO_x reduction by Selective Non Catalytic Reaction (SNCR) is next to the Selective Catalytic Reaction the most common way to reduce NO_x in flue gas.

A reduction agent is mixed with water for distribution, atomized by compressed air and sprayed by lances into the flue gas. Urea or ammonia are common reduction agents.

The amount of reduction agent is controlled by the resulting NO_x reduction which is measured by means of the NO_x emission measurement system. Most components of the SNCR system are located in so-called mixing and dosing modules adjusting the flows to the injection lances. These lances have to be arranged in a way to provide a very good distribution of the reduction agent in the boiler cross section within the required reaction temperature range. Moreover, sufficient reaction time is required to achieve an optimum NO_x reduction with minimum NH₃ slip at the same time.

The basics of the SNCR technology are well-known [1]. Furthermore, sample projects have already been presented demonstrating that 100 mg/Nm³_tr. NO_x together with 10 mg/Nm³ had been met in a first phase of developments of the SNCR Technology [6]. The introduction of online temperature measurement systems has been a very important step forward. Existing units are requiring a case-by-case analysis to engineer the best possible process and components improving the plant’s denitrification in order to meet the new targets of 150 mg/Nm³ NO_x and 10 mg/Nm³ NH₃.

The following impacting parameters have to be analysed and evaluated when developing a new SNCR concept:

• Temperature at the injection points

• Impact of the boiler running time to the temperature profile

• Variation of the fuel heating value including seasonal variation of humidity in waste

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• NO_x raw gas concentration including their range

• Retention/reaction time for the SNCR reaction

• CO levels in the injection zone

• Load variations

• Distribution of the reduction agent

• Distance of the injection levels

• Instrumentation and control of the SNCR

• Type of reduction agent

Figure 1 is showing a sample of NO_x reduction and NH₃ slip depending on flue gas temperature for a given flue gas composition. The NO_x control efficiency is increasing up to an optimum temperature of about 980 °C. At higher temperatures, the NO_x reduction is decreasing due to the increased side reaction of oxidizing ammonia instead of reacting with NO_x. On the other hand the ammonia slip is decreasing with higher temperatures. At very high temperatures, NH₃ is oxidized and N₂ or even more NO_x is formed. Figure 1 also shows the older and actual temperature design range to meet even challenging NO_x reduction limits as well as the new ammonia limit of 10 mg/Nm³. Since there was no ammonia slip limit defined in Germany before 2016 it was possible to inject the reduction agent in a very wide temperature range of about 850 °C to 1,095 °C.

Usually, one active injection level was sufficient in order to meet the required moderate NO_x reduction level. The load had to be slightly reduced at the end of the boiler running period in order to reduce the temperature at the injection level. The new limits and even locally lower NO_x emission limits are requiring an improved NO_x reduction. Therefore, the lower SNCR temperature limit needs to be increased to limit the slip and the upper SNCR temperature limit needs to be reduced to achieve the higher NO_x reduction.

100

80 90

70 60 50 40 30 20 10 0 NO_X Reduction

%

NH₃ Slip mg/m³ 20

16

12

8

4

0

750 850 950 1,050 1,150

Reaction Temperature °C operatingnew

range

old operating range

Figure 1:

NO_x reduction and NH₃ slip depending on temperature, former and new SNCR design base

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In order to meet the 150 mg/Nm³ NO_x limit the permitted operational temperature is ranging from about 930 °C to 1,075 °C. The new temperature range being shown in Figure 1 is even more restricted since it shows a very challenging NO_x reduction efficiency of about 75 %. Please note that these temperature windows have to be adapted for special plants in order to take the available residence time and other constraints such as residual CO contents into consideration.

Consequently, the reduction of the permitted SNCR temperature operational range is influencing the denitrification result, the SNCR design and firing system operation as well as the achievable boiler running time. Usually, more injection levels and modified controls of the injections are required, see also [1] and [5]. In case of a non-ideal initial design of the original SNCR the distance between the levels has to be reduced in order to also reduce temperature imbalances between injection levels and to switch the lances as close as possible to the optimum SNCR operational temperature.

Much more care has to be taken to consider impacts of load changes, differences in fuel composition and heating value as well as oxygen distribution. Especially, the fast varying heating value of the waste requires new SNCR control concepts as well as a more sophisticated novel approach of the SNCR design.

Besides temperature deviations, larger deviations of primary NO_x emissions result in increased emissions of NH₃ and clean gas NO_x. Conventional SNCR control schemes are based on the comparison of actual to target NO_x clean gas value. Thus, it is a backwards orientated control always requiring to measure the result of the denitrification. Deviations of the raw gas NO_x-content cannot be taken into consideration. Therefore, such deviations of the raw gas NO_x – either produced by higher N-content of the waste or due to more primary NO_x production – are another source of not meeting stringent emission limits.

To sum up, the new emission limits require a modified approach and a very careful process design. The mentioned conflict between matching a narrower SNCR temperature range despite high temperatures at high loads at the end of the boiler running time is worth a detailed analysis and upgrades of non-flexible SNCR installations. Respective conventional samples are presented in [4].

2. Challenging NO

_x

reduction

All operators of waste-to-energy plants are focusing on burning waste and producing energy while minimising operating and maintenance cost. Providing ideal conditions for SNCR operation is of secondary importance. How to define Challenging NO_x Re- duction in case of a thermal waste treatment facility?

In chapter 2 the main factors are listed in details which are important to achieve high NO_x reduction with low ammonia slip. An even more detailed overview is described in [2].

As far as these factors such as temperature window, residence time, fast response to deviating fuel and combustion conditions cannot be controlled in a proper way the results will substantially differ from the requested performance level. Therefore, it is a challenge to design a system which is able to overcome those obstacles.

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Besides, the following items are often monitored in waste-to-energy plants resulting in not meeting the constraints laid down in chapter 2 being required for a high efficient denitrification:

• Deviating heating value of the fuel,

• Large seasonal differences of the waste composition including humidity,

• Fast slagging of the first boiler pass,

• Fast changing loads,

• Insufficient burn-out,

• Strong temperature imbalances,

• Non-adjusted firing control system.

The result of challenging conditions can be graphically shown by means of the so-called scale. The measured values of NH₃ and NO_x downstream of the SNCR are reverse pro- portional to each other. While trying to improve one of them by means of adjustments this will result in an increase of the other emission value. Figure 2 shows a sample for 100 mg/Nm³ NO_x and 10 mg/Nm³. The axis of the diagram are scaled in a way that the limits of both pollutants NO_x und NH₃ are on the same horizontal line. As soon as the intersecting points are meeting in another horizontal line above the limits-line it is a challenging NO_x reduction system. If the NO_x-concentration is reduced below the limit-line by means of adding more reduction agent, the ammonia slip is immediately increasing above its limit. As a reaction of the control system the reduction agent flow will be reduced to meet the ammonia slip limit, however, resulting in a fast increase of the NO_x concentration above the NO_x limit.

Unfortunately, the average values are not adjustable in a more appropriate way in such cases due to limitations of the installed SNCR process and its controls. Consequently, only one emission limit will be met in average and it has to be accepted that the other one is above its limit.

0 5 10 15 20

0 50 100 150 200

NH₃ mg/Nm³ NO_x

mg/Nm³

Scale for insufficient denitrification

NO_x mg/Nm³ NH₃ mg/Nm³

Figure 2:

Schematic showing the balance between NO_x and NH₃ values during insufficient denitrification above 100 mg/Nm³ NO_x and 10 mg/Nm³ NH₃

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As a result of such analysis the only solution is a modification of the SNCR. Flexibility and more reduction potential below the limits are required to lower the actual line of the intersection points below the level of the limit-line. ERC Technik GmbH developed respective solutions covering also such challenging NO_x reduction issues.

Improving NO_x reduction has to be the target in order to lower the intersection-line below the limit-line, Figure 3.

0 5 10 15 20

0 50 100 150 200

Scale for a good denitrification NH₃ mg/Nm³ NO_x

mg/Nm³

NO_x in mg/Nm³ NH₃ in mg/Nm³

Figure 3:

Schematic showing the balance between NO_x and NH₃ values during good denitrification below 100 mg/Nm³ NO_x and 10 mg/Nm³ NH₃

Figure 4 shows a SNCR Mixing and Metering module of a standard denitrification.

Figure 4:

Standard mixing and metering module

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Figure 5 shows the result of a standard denitrification SNCR before installing a novel Dual Injection SNCR system. It can be recognized that the average values of the NO_x and NH₃ curves are above the respective limits of this sample 100 mg/Nm³ NO_x and 10 mg/Nm³ NH₃. If one of those values is decreasing below its limit the respective other limit is increasing above this limit.

NOx mg/Nm³ NH3 mg/Nm³

Fuel mass flow t/h 200

100

0

20 36

10 18

0

10:00 16:00 22:00 0

04:00

30.08.2013

Figure 5: Insufficient NO_x reduction before SNCR refurbishment – scale above limit values

3. Dual injection SNCR technology

In order to increase flexibility and provide process margins ERC Technik developed its Dual Injection SNCR process. The amount of reduction agent is calculated and it is injected by means of those levels which are above and below the optimum SNCR operation temperature.

The Dual Injection process is based on the following principle:

The first reaction step is taking place at higher temperatures. Thus, there is very limited risk of slip production. The amount of reduction agent to the first level is serving for a pre-removal of NO_x. However, the temperature at this first level is too high to meet the required total NO_x reduction. Therefore, a second reaction stage is located just upstream of the first level showing a lower temperature being close to the optimum SNCR temperature. Usually, the NO_x reduction efficiency is somewhat higher compared to the first stage. However, at this lower temperature there is a tendency to emit more ammonia being necessary to limit the NO_x reduction efficiency of this level below the maximum one. Figure 6 shows both reaction stages within the SNCR temperature window diagram and explains the process of the Dual Injection system.

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It is expected that larger and more recently installed waste-to-energy plants are not necessarily requiring this Dual Injection technology to meet the new German emission limit of 150 mg/Nm³ NO_x in combination with 10 mg/Nm³ NH₃. In most of such cases these plants are having larger cross sections with reduced flow velocities in the first boiler pass. Consequently, their burn-out is very good, disturbing CO concentrations are low and the retention time for the SNCR reaction is long enough to achieve a very good performance. However, the new Dual Injection technology has been proven as been very effective for boilers targeting even lower emissions such as 100 mg/Nm³ NO_x combined with 10 mg/Nm³ NH₃. Moreover, the Dual Injection technology is applicable for smaller boilers operating with high flue gas speeds and very often at overload. In some cases this novel technology was the only successful process to solve a very challenging NO_x reduction problem.

100

80 90

70 60 50 40 30 20 10 0 NO_X Reduction

%

NH₃ Slip mg/m³ 20

16

12

8

4

0

750 850 950

Reaction Temperature °C

reaction zone 2 reaction zone 1

1,050 1,150

Figure 6:

SNCR reaction window, dual injection

Altogether, the amount of reduction agent of this process is similar or even below the reduction agent amount of a single stage injection being secured by means of a special controller.

The total amount of reduction agent is determined by means of the NO_x-difference across both stages. The result of the Dual Injection system is significantly improved in comparison to the less flexible single stage injection systems.

All injection levels are designed and arranged in a comparable way to the conventional single stage process. Therefore, it is not mandatory to install a second level of lances just below an existing level.

injection in reaction zone 2

injection in

reaction zone 1 flue gas

Figure 7: Schematically lance arrangement, dual injection SNCR

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It is more important to achieve a better coverage of the boiler’s cross section by means of arranging of the lances in an appropriate way to react to the temperature profiles.

Figure 7 presents a schematic arrangement of a Dual Injection system.

Figure 8 shows the mixing and metering module of a Dual Injection SNCR after refurbishment of the original single stage SNCR. It is arranged close to the mixing and metering module of the former single stage process as shown in Figure 4.

Figure 9 shows the result of the refurbished system with Dual Injection System employ- ing the new module, Figure 8. The NO_x reduction is clearly improved. Both limits NO_x and NH₃ are met. The intersection line is arranged below the limit-line of NO_x und NH₃.

Figure 8:

Mixing and metering module after modification to dual injection SNCR

NOx mg/Nm³ O2 Vol.-%

NH3 mg/Nm³

100

0

13 10

0

16:00 17:00 18:00 0

15:00

30.08.2013

Figure 9: Good NO_x reduction after dual injection SNCR refurbishment – scale below limit values

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4. Improved monitoring and control

As shown in chapter 2, the control of the SNCR, more precisely the control of the reduction agent’s quantity, is of decisive importance for the quality of the real process.

The quality of the control depends on the type of control parameters as well as on the speed with which it can be used. Thus, for example, the value of the load respectively of the steam production, as still used in some old systems, is entirely unsuitable to control the SNCR. In fact, the control has to be depend on absolutely current values of temperature, flue gas amount and NO_x content.

Proven systems are available to measure the temperature as well as the flue gas quantity.

These correspond to the technical standard.

The NO_x raw gas value is required in order to adjust the quantity of reduction agent.

However, this value cannot be measured prior to the SNCR. Therefore, in case of a classical SNCR control, the quantity of reduction agent is controlled according to the deviation of the result of the denitrification from the set point. In this case, the nitrogen measurement provides the NO_x pure gas value. Indeed, the delay of the SNCR process to the pure gas measurement became apparently disadvantageous when tightening the limit values. A NO_x measuring unit can be installed behind the combustion chamber in the cooler temperature range to reduce the dead time. Moreover, it is also possible to install a NH₃ measuring unit. By means of contemporary measured values of NH₃ or NO_x behind the boiler the SNCR can be controlled precisely due to the fact that the dead time is drastically reduced. Several plants are already controlled in such a way.

If such measurements are not available, the Opti-Link system can be used [2]. The NO_x raw gas value can be calculated by balancing of measured energy and material flows and can be used for the contemporary control of reduction agent’s quantity. If the SNCR is switched off during a test, the calculated and measured value for NO_x can be directly compared. Figure 10 shows both values in comparison.

NO_x mg/Nm³ 500

400

300

200

100

0

NO_x calculated NO_x measured

00:00:00 00:11:31 00:23:02 00:34:34 00:46:05 00:57:36 01:09:07

Figure 10: NO_x raw gas value, measured and calculated via Opti-Link

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A measured value is preferable in case it is used for control only and provided the measurement is sufficiently accurate.

Furthermore, the benefits of balancing the NO_x-value are additionally based on other positive side-effects [3]. Through this arise advantages which also take effect if one measuring unit is installed directly downstream of the boiler.

4.1. Plausibility check

A plausibility check can be used to determine whether the indicated measured values are correct. If there are large differences within the balances after recalculation, at least one of the measuring units must be incorrectly calibrated or the conversion factor programmed at commissioning is not accurate.

4.2. Online check of the measured value drift

If online monitoring is carried out within the system according to the principle of the plausibility check, the drift of the measuring devices can be monitored. Thus, the system indicates whether one of the measuring instruments operates outside the permissible tolerance range.

4.3. Online calorific value

fuel mass flow t/h

calorific value MJ/kg

time

time 25

20 15 10 5 0

25 20

15

10 5

0

mass balance study (online balancing) indicated value

energy balance (with fuel mass flow indicated value)

energy balance (with online mass balance study) calorific value

formula

Figure 11: Fuel mass flow and calorific value over period of time

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Opti-Link allows the extraction of those parameters from the balancing, which cannot be measured with measuring instruments contemporarily or with difficulties only. Besides the NO_x raw gas value, this also applies to the calorific value of the combusting waste.

The calculation of the calorific value is carried out without the input of the crane scale.

It is immediately generated from available values and, thus, is actually available online.

Figure 11 shows the fuel mass flow and calorific value over a period of time. The dotted lines illustrate the values indicated in the control room, including in its calculation time-delayed values of the crane scale. The solid lines are derived from the balancing.

4.4. Fractionation

To determine the NO_x raw gas value, the fractionation of the waste is first approxima- ted. It may be interesting for the operator to record the data on the composition of the waste over the annual course. Figure 12 shows a calculated fractionation of the waste combusted during the calculation period.

paper, cardboard 10 %

textiles 23 %

plastic 20 %

wood 20 % organic

5 % inert 16 %

bulky waste 4 %

Fe und NE 2 % glass 1 %

hu MJ/kg 14.776

C kg/kg 0.36

H kg/kg 0.05

O kg/kg 0.20

N kg/kg 0.01

S kg/kg 0.00

C/H 7.59

W kg/kg 0.27

A kg/kg 0.10

CI,_total kg/kg 0.01

C_fossil %C 41.83

L_min,dry m³L/kgBS 3.82

Figure 12: Examplary Waste Fractionation

5. Profitability

Figure 13 shows the temperature of the flue gas at the last injection level as well as the steam load at a continuous operating period. It can be clearly seen that the load has to be lowered at the end of the operating period in order to obtain the required temperature for denitrification. In such a case an extension of the plant by an additional level and the Opti-Link with dual injection is profitable in two aspects. Firstly, the load can be kept constant over the entire operating period so that the waste incineration plant can process constant amounts of waste at any time. Secondly, the efficiency of the denitrification is improved, i.e. reduction agents can be reduced by up to twenty percent based on the new limit values.

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Flue Gas Treatment Figure 13: Temperature and load during continuous operating period

A further advantage of upgrading the plant with the Opti-Link is the detection of possible measurement errors during the O₂ measurement due to the plausibility check as well as the online drift detection. Even small deviations of the O₂ value cause high amounts of additional flue gases and, thus, an overall energy efficiency loss.

6. Flexibility or simplification?

The more the mentioned parameters of a combustion vary, the higher the degree of flexibility of the SNCR has to be. Consequently, the quality of the input parameters increases, too.

Opti-Link and Dual Injection as well as a detailed investigation of the incineration plant’s operation [4] continue to pursue this direction.

The tendency must therefore clearly lead to thorough analysis and flexible high-performance SNCR systems, which will cope with every situation. The reduction of the temperature window as shown in Figure 1 requires that, due to the more complicated conditions, the optimum ranges are accurately hit, NO_x flue gas values are contemporarily recorded or the raw gas value is calculated.

Sometimes attempts are being made to save expenses in improved plant technology in order to reduce the initial investment costs. However, in such cases the effects of deviations of the conditions in the combustion chamber are from time to time substantial

time (00:00:00) 01.07.1301.08.1

3

01.09.1301.10.1301.11.1301.12.1301.01.1401.02.1401.03.1401.04.1401.05.1401.06.1401.07.1 4 1,000

900

800

700

600 60.0

52.5

45.0

37.5

30.0

∆ Load

T ≈ const.

Temperature

°C Load

t/h steam

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and cannot be treated without limiting operation of the boiler. Indeed, the NH₃ slip can be excessively high and/or the consumption of the reduction agent also increases significantly.

The knowledge and use of the characteristic of the atomization is a fundamental component of a successful denitrification concept. Easier more simple injection systems are only limitedly successful.

7. Conclusion

By using technologies that increase the degree of detailing and flexibility, the challenges of denitrification can be overcome.

A modern SNCR is able to use the best possible reaction areas which can be reliably detected by means of sophisticated analytics.

Gaps in the analysis can now be concluded with special calculation algorithms. The calculated parameters are directly incorporated into the control of the SNCR. As a result the SNCR is resistant against occurring fluctuations. Using Opti-Link, it is also possible to calculate parameters required to standardize the combustion control system. Thus, the conditions for a denitrification are improved and the operator is given further advantages due to a steadied operation.

The plausibility check of the measured values and the control of the measured value drift means safety for the operator since he can protect himself against false measured values and their consequences.

The novel Dual Injection process significantly increases the process stability of the SNCR. The different, adapted concentrations in the double denitrification provide excellent denitrification results. The additional constructional effort required for this technology is limited to a few additional fittings. In most cases the injection can be effected on layers being necessary for covering the occurring temperature fluctuations anyway.

The combination of the processes ensures the sustainability of the SNCR beyond the new limit values.

Non-flexible SNCR systems must necessarily fail if the parameters of the combustion system are not kept absolutely constant. It was shown that the necessary complexity of the SNCR system depends on the conditions of the combustion, the required limit values as well as the permitted consumption rates. Simplified plant concepts often ignore this context. In the end the operator of an incineration plant does not save anything when purchasing a cheap SNCR as the money saved is quickly spent due to a more expensive operation of the plant. In addition, less income is generated during the subsequent operating period.

Thus, the investment into an optimized SNCR pays off for the operator, since the optimal use of reduction agents, lower maintenance costs and the extension of the operating period lead to increased profits.

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8. Literature

[1] Hukriede, J.; Pachaly, R.; Reynolds, P.: Neue 17. BImschV – Auswirkungen auf bestehende Ab- fallverbrennungsanlagen mit SNCR-Technik sowie Lösungskonzepte. In: Thomé-Kozmiensky, K. J.; Beckmann, M. (eds.): Energie aus Abfall, Band 11. Neuruppin: TK Verlag Karl Thomé- Kozmiensky, 2014, pp. 559-574

[2] Pohl, M.: Vom Brennstoff zum Rauchgas über Combustion 4.0. In: Kraftwerkstechnik 2015.

Freiberg: Saxonia, 2015, pp. 367-375

[3] Reynolds, P.: Günther, C.: Technisches und wirtschaftliches Potential der Online-Bilanzierung.

In: Thomé-Kozmiensky, K. J.; Beckmann, M. (eds.): Energie aus Abfall, Band 13. Neuruppin:

TK Verlag Karl Thomé-Kozmiensky, 2016, pp. 303-316

[4] Schüttenhelm, W.; Reynolds, P.: SNCR for Low NO_x Emissions – Case Study of a Swedish Waste- to-Energy plant. In: Waste managment. Neuruppin: TK Verlag Karl Thomé Kozmiensky, 2015, pp. 221-236

[5] Schüttenhelm, W.; Reynolds, P.; Hukriede, J.: Einhaltung verschärfter NO_x- und NH₃-Grenzwerte bei bestehenden Anlagen – Vorgehen und Lösungsansätze anhand von Praxisbeispielen. [book auth.] Karl J. Thomé-Kozmiensky and Michael Beckmann. Energie aus Abfall, Band 12. Neu- ruppin: TK Verlag Karl Thomé-Kozmiensky, 2015, 373-390

[6] Tappe, T.: Feuerraumdiagnose und SNCR-Optimierung in einem EBS Kraftwerk. Potsdam:

Potsdamer Fachtagung, 2011

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Schwenksegement Nullzyklus (Nullpunktreflektor und Dunkelblende)Schwenksegement Nullzyklus (Nullpunktreflektor

(Nullpunktreflektor

, ThielIMMISSIONSSCHUTZ

4

Thomé-Kozmiensky • Löschau

K.J. Thomé-Kozmiensky Michael Hoppenberg

IMMISSIONSSCHUTZ

– Planung, Genehmigung und Betrieb von Anlagen – Band 1

1

Thomé-Kozmiensky, Hoppenberg , ThielIMMISSIONSSCHUTZ

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Karl Joachim Thomé-Kozmiensky Matthias Dombert

Wolfgang Rotard Markus Appel

Andrea Versteyl

– Planung, Genehmigung und Betrieb von Anlagen – Band 2

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Thomé-Kozmiensky Dombert, V

ersteyl, Rotard, Appel , ThielIMMISSIONSSCHUTZ

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K.J. Thomé-Kozmiensky Stephanie Thiel

Markus Appel Andrea Versteyl

Wolfgang Rotard

– Aktuelle Entwicklungen im anlagenbezogenen Planungsprozess und Immissionsschutz

Band 3

3

Thomé-Kozmiensky Versteyl, Thiel, Rotard, Appel , Thiel

Recht – Anlagenbetrieb – Optimierung – Emission K. J. Thomé-Kozmiensky Margit Löschau

Band 4

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Thomé-Kozmiensky • Löschau , Thiel

Recht – Umsetzung – Messung – Emissionsminderung K. J. Thomé-Kozmiensky Margit Löschau

Band 5

4

5

Michael Boneß

123

Messung

Tabelle 1:

Störkomponente Konzentration QE auf die Hg-Messung

SO2 1.000 mg/m2 – 0,065 µg/m3

H2O 30 Vol.-% 0,060 µg/m3

HCI 200 mg/m3 keine QE

NO 300 mg/m3 keine QE

NO2 30 mg/m3 0,090 µg/m3

O2 21 Vol.-% – 0,120 µg/m3

Alle weiteren getesteten QE‘s < ± 0,05 µg/m3

5. Anwendungsbereich des neuen Messverfahrens für die Emissions- und Prozessmessung bei Verbrennungsanlagen Emission

Das neue Messverfahren konnte bereits für die Emissionsüberwachung des Gesamt- anlagen) ohne Leistungseinbußen oder Einschränkungen erfolgreich absolviert.

Für den Standardmessbereich von 0 bis 45 µg/m³ gilt an allen drei Anlagen ein War- tungsintervall von sechs Monaten.

Prozess (Rohgasanwendung)

Aufgrund der einfachen Bauweise und der Gasentnahme ohne zusätzliche Hilfs- und Re- Die Resultate der Testinstallationen zeigen hierbei die Flexibilität des eingesetzten Messver- fahrens, sowohl für den kleinsten Messbereich von 0 bis 10 µg/Nm³, als auch bis in den sehr hohen Konzentrationsbereich von bis zu 4.000 µg/m³ (Bild 10). Eine schnelle, zuverlässige möglich, wieder rot markierte Peak zeigt (Bild 11). Das Messsystem kommt dabei unverän- dert gegenüber der Emissionsmesseinrichtung zum Einsatz und ermöglicht dem Betreiber bzw. unbekannter Zusammensetzung. Im vorliegenden Beispiel an einer kommunalen Hausmüllverbrennungsanlage betrug die Grundlast im Durchschnitt etwa 200 µg/Nm³.

Allerdings traten auch immer wieder Spitzen von bis zu 3.000 bis 4.000 µg/m³ auf, was natürlich entsprechende Maßnahmen für die Gasreinigung, um den Grenzwert von des markierten Peaks verdeutlicht die schnelle Reaktionszeit der Messung sowohl im Anstieg, als auch im Abklingen der Hg-Konzentration (Bild 12).

Sowohl bei Abfallverbrennungsanlagen und insbesondere auch bei Sondermüllver- brennungsanlagen ist das Interesse an diesen Messungen sehr gestiegen. Denn mit der Hg-Rohgasmessung verfügt der Betreiber über eine Überwachung, die zum frühestmög- lichen Zeitpunkt eine mögliche Überladung von Hg für die Abgaswäsche signalisiert und Raum für Gegenmaßnahmen lässt.

124 Messung von Quecksilber

Messung

typischerweise durch SO2 und andere Gaskomponenten bekannt sind, treten bei diesem Verfahren nicht auf (Tabelle 1). Vergleichende Messungen an Anlagen mit bestehenden Quecksilber CEMS zeigen eine hervorragende Übereinstimmung, ebenso im Vergleich zu Optional können für die regelmäßige Qualitätskontrolle der Messungen automatisiert HgCl2-Konzentrationen über eine integrierte Verdampferapparatur aufgegeben werden.

Ejector Messgaszelle 1.000 °C Optik/Detektor Klimagerät Kalibriergas-generator (ohne Abdeckung)

blau= Untergrundmessung;

orange= Hg-Absorptionsmessung Hg-Linienaufspaltung durch Magnetfeld an der Lichtquelle Bild 7: Schrankansicht des kontinuierlichen Quecksilber-Messverfahrens MERCEM300Z (außen und innen)

Bild 8: Zeeman-AAS Messprinzip Bild 9:

Quarzmessgaszelle bei 1.000 °C zur Konvertierung und gleich- zeitigen Echtzeitmessung (pa- tentiert)

Immissionsschutz, Volume 1 Released: 2010

ISBN: 978-3-935317-59-7 Hardcover: 632 pages Price: 30.00 EUR

ISBN: 978-3-935317-90-0 Hardcover: 664 pages Price: 40.00 EUR Immissionsschutz, Volume 4

Released: 2014

Package Price

Immissionsschutz, Volume 1 – 5

150.00 EUR

save 80.00 EUR Immissionsschutz, Volume 5

Released: 2015

Editors: Karl J. Thomé-Kozmiensky et al. • Publisher: TK Verlag Karl Thomé-Kozmiensky

(18)

Bibliografische Information der Deutschen Nationalbibliothek Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.dnb.de abrufbar

Thomé-Kozmiensky, K. J.; Thiel, S.; Thomé-Kozmiensky, E.;

Winter, F.; Juchelková, D. (Eds.): Waste Management, Volume 7 – Waste-to-Energy – ISBN 978-3-944310-37-4 TK Verlag Karl Thomé-Kozmiensky

Publisher: TK Verlag Karl Thomé-Kozmiensky • Neuruppin 2017

Editorial office: Dr.-Ing. Stephanie Thiel, Elisabeth Thomé-Kozmiensky, M. Sc.

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