Monitoring of Exhaust Gas Parameters of Stationary Combustion Systems In View of Environmental Standards

Transcription

1 ENGINEER - Vol. XLVIII, No. 01, pp. [51-60], 2015 The Institution of Engineers, Sri Lanka ENGINEER - Vol. XLVIII, No. 01, pp. [page range], 2015 The Institution of Engineers, Sri Lanka Monitoring of Exhaust Gas Parameters of Stationary Combustion Systems In View of Environmental Standards K. T. Jayasinghe Abstract: During the last few years, fossil fuel consumption for electricity generation and industrial process activities has gradually increased with the rapid development of energy and industrial sectors in Sri Lanka. When the fuel consumption increases, the relative quantities of emissions released to the environment too will increase. Such types of common emissions are toxic gases (Pb, Cl 2), noxious gases (SO x, NO x), green house gases (CO 2, O 3), unburned gases (CO, C xh y), volatiles and respirable particles. Those emissions will harmfully affect, in different ways, the human health and the environment. The regulatory bodies have actively monitored the industrial emissions by implementing & amending old inactivated policies, regulations and standards. As a result of such implementaions, under the Section 32 of National Environmental Act No. 47 of 1980 as amended by Acts 56 of 1988 and 53 of 2000, the latest enviormnetal standard for emission regulations for staionary combustion systems has emerged. In this regard, this paper aims to broadly discuss the experience gathered by the author in this area,in (view of) relation to? industrial impacts, instrumentations, pre facility requirement & resource availability and external interferences. Further the recommendations made in this paper for individual combustion systems, such as, thermal power plants, standby generators, industrial boilers & thermic fluid heaters, incinerators and cupola furnances, kilns etc. might be helpful to the regulatory bodies, industries, instruments & equipment suppliers and monitoring organizations in different ways when introducing (introduce) those emission standards to the industries. Finally, the outcomes of this study will help not only the local industries, but also Asian regional countries which have been operating similar combustion systems, to upgrade their systems to comply with particular environmental standards, because the proposed local standards have been prepared based on the other Asian and Europian regions environmental standards. Keywords: Particulate Matter, Smoke Opacity, Isokinectic, Ringelman, Transmissivity, Themic Fluid 1. Introduction: Sri Lankan Statistics reveal that the industrial growth and electricity generation had increased by 11.0% and 7.9% respectively in 2010 [SEA Annual Report 2010]. It is expected that the industrial growth and electricity generation will further increase in the coming years due to the introducion of new development projects and rapid increase in electricity demand island wide. According to the current statistics, electricity generation heavily depends on the thermal power plants and in 2010 around 60% of the total generation had been shared by thermal power plants [SEA Annual Report 2010]. The main energy sources used in thermal power plants are fossil fuels and coal. In addition to that few bio fuel in-house electricity generation facilities have ENGINEER 51 1 been operated especially in process industries such as activated Carbon production, rice processing, Sugar industries etc. Industrial development also contributes to the exponential increase of fossil fuel consumption to obtain required thermal and electrical energy. The common systems practices are steam & hot water boilers, thermic heaters, diesel electricity generators etc. In addition to those electrical and thermal energy generating systems, a remarkable number of different types of stationary combustion systems such Eng. K T Jayasinghe, CEng., MSc (Energy), MIE(Sri Lanka), Research Fellow, National Engineering Research & Development Centre (NERDC), 2P/17B, Industrial Estate, Ekala, Ja-Ela. Sri Lanka. ENGINEER

2 as incinerators, crematoria, cupolas, kilns, furnaces etc. are in operation island wide. Out of those, many plants are out dated and they are operated under very low efficiency levels. Setting up of unplanned and inefficient combustion systems will increase the pollution gases and contaminants emitted to the atmosphere. The common emissions released to the atmosphere are toxic gases (Pb, Cl 2), noxious gases (SO X, NO X), green house gases (CO 2, O 3), unburned compounds (CO, C XH Y), Suspended Particles (SP) and respirable particles etc. Different kinds of emissions in small and medium processing plants such as boilers, thermic heaters, incinerators etc. are rather difficult to control than the emmisions in centralized large processing plants in thermal power generation, co generation, cement processing etc. In this context, adverse effects from small and medium stationary combustion systems to the environment might be high. Even though the environmental policies have been introduced since Colonial times, policies related to emission from stationary combustion systems had not been strictly practiced by responsible parties. However, the regulatory bodies have been actively involved, in the last few decades, to implement such regulations aiming to control environmental emissions from stationary combustion systems. In fact, this paper is not going to discuss the policy implementations or regulation practices by different organizations to monitor the environmental pollutions of stationary combustion systems. However, it broadly discusses the experience gathered by the author; under different types of stationary combustion systems, with respect to industrial impacts, instrumentations, pre facility requirement etc. 2. Review of Emission Standards of Combustion Systems in Sri Lanka The implemented emission standards of stationary combustion systems have mainly focused on three major areas such as source categorizations & measuring parameters, measuring regulations & techniques, and system requirements. 2.1 Source Categorizations & Measuring Parameters According to the type of plants available in the country, stationary combustion systems have been divided in to 5 categories such as thermal power plants, boilers, thermic fluid heaters, incinerators, and cupolas, furnaces, ovens, kilns etc. The recommended monitoring parameters and emission levels of each category depend on the plant capacity and fuel used. The recommended monitoring parameters of different combustion sources are summarized in Table 1. Table 1 - Summarized Monitoring Parameters of Stationary Combustion Systems Plant Category Particulate Matter Smoke Opacity Cupolas, Furnaces, X X X X Ovens, Kilns [Source Schedule II Part I to Part V of National Environmental Act No. 47 of 1980] According to Table 1 the common monitoring parameters of each combustion system are Particulate Matters (PM), Smoke Opacity, Oxides of Sulfur (SO X) and Oxides of Nitrogen (NO X). In additions to these common parameters, thermal power plants driven by solid wastes and waste combustion incinerators require to monitor CO, HCl, Hg, Pb and Dioxin & Furans. The recommended emission levels of each substance are not discussed in this paper. [Reference: - Section 32.0 of National Environmental Act. No 47.0 of 1980 for the recommended values]. 2.2 Measuring Regulations & Techniques The emission monitoring methods described in this standard are based on the standard conditions, and the monitoring parameters are SOX NOX CO HCl Hg Pb Dioxin & Furans Thermal Power Plants- Any Fuel Except Solid X X X X Waste Thermal Power Plants Solid Waste Fuel X X X X X X X X - Boilers X X X X Thermic Fluid Heaters X X X X Incinerators X X X X X X X X X ENGINEER 2 ENGINEER 52

3 estimated based on the reference levels in order to bring the monitoring parameters by different organizations to a common standard format. Based on the regulations, the emission parameters shall be, - Monitored by instrument/ equipment based - Converted in to dry basis & normal condition (0 0 C and 760mm Hg) - Corrected for relevant reference Oxygen level. [Schedule 1 of National Environmental Act. No 47 of 1980 for reference Oxygen levels]. However the detailed descriptions of equations, conversions and regulations are not included in this paper. [Reference: - Section 32 of National Environmental Act. No 47.0 of 1980 for details]. 2.3 System Requirements and Limitations System requirements of this standard are described in order to control the toxic gases; especially SO 2 and NO X. The key factors discussed under the system requirements are; - In any case, the stack (chimney) height shall not be less than 20m - In case of power plants, SO 2 shall be controlled by fuel quality and stack height, if SO 2 emission levels are not specified in the standards. - Dioxin and Furan emission from incinerators shall be controlled by maintaining temperature within C to C and 2-3 seconds retention time in secondary chamber. 3. Monitoring Methodologies and Techniques In-depth analysis of monitoring methodologies and techniques related to PM, Smoke Opacity, SO X and NO X are important, since all the combustion systems shall be required to monitor those emissions as common parameters. In general, two monitoring methodologies, instrument/equipment based and titration based, are available for gaseous emission estimations. However only the instrument/ equipment based methods are described in this paper, since the monitoring methods described in particular standards are based on the instrument / equipment method. 3.1 Monitoring of Particulate Matters (PM) Test Method and Instrumentation The common method used for stack PM monitoring is In-stack Filtration Method. In this method, PM is withdrawn isokinetically from the source and collected on a glass fiber filter maintained at a temperature, as specified by applicable standards, or approved by particular application. The PM mass which includes any material that condenses at or above the filtration temperature is determined gravimetrically after the removal of uncombined water. The basic components of standard PM monitoring sampling train are probe nozzle; probe extension, filter holder, barometer, Pitot tube, differential pressure gauge, condenser, metering system, vacuum pump and heating element. The common arrangement of the instrument train is illustrated in Figure 1. Figure 1 Basic Components of PM Monitoring Sampling Train [Source-Envirotech APM 621] ENGINEER 3 53 ENGINEER

4 3.1.2 Applicability, Limitations and Facility Requirements for PM Monitoring The fundamental principle behind any sampling analysis is that a small amount of collected sample should be a representative of all the particles being monitored. Therefore variations in concentration, temperature or velocity across the duct, moisture, gas leakage or air infiltration can affect the measurements. Further the number of samples, monitoring locations and port sizes will depend on the homogeneity of the gas stream. Therefore for accurate measurements, it is required to follow the basic and standard methods. [Reference - BS EN :2002 or any other acceptable standards]. According to the standards, PM sampling stations should be located at few meters above (depends on the stack arrangement) the ground level. Therefore it is important to facilitate a safe system set up for both operators and instruments. In this regard, a safe and permanent working platform and a lifting arrangement shall be required to reach the sampling locations. However, in exceptional circumstances; such as old plants or where the owner cannot bear the setting up facility cost (especially in small scale industries), temporary structures; scaffolding, mobile crane/lift etc. can be used. All the platforms, whether permanent of temporary, shall meet the standard dimensions, weight criteria, protection, facility requirements etc. [Reference - EN :2002 or any other acceptable standards]. 3.2 Monitoring of Smoke Opacity Smoke Opacity is a property of a substance, especially unburned Carbon, which renders it partially or wholly obstructive to the transmission of visible light and it is expressed as the percentage to which the light is obstructed. [New Jersey Air pollution Control Act N.J.A.C. 26:2C-1]. Based on the standards [Ref. - Table 1.0], smoke opacity monitoring is common for any combustion system and shall be maintained below the recommended levels such as 10%, 15%, 20% etc. Usually, two monitoring methods have widely been practiced to measure smoke opacity. Those are the plume visual inspection method - Ringelmann and the Dual Beam Method Test Methods, Instrumentations and Limitations (a) Ringelmann Method:- Ringelmann Method is a visual assessment method and the darkness of smoke emitting at the top of the stack is compared with the standard shades of grey chart (called Ringelman) placed at a certain distance from the observer. The system arrangement is illustrated in Figure 2. The Ringlmann method cannot be applied to many combustion systems operated island wide. This is because according to the physical set up of the Line system, of Sight, most of the stacks are covered or obstructed by adjacent buildings, trees or any other objects. Further the accuracy of test results totally depends on the appearance of a plume as viewed by an observer, angles of the observer with respect to the plume & the sun, the point of observation of attached & detached stem plume, nature of day light and the wind velocity. Figure 2 Ringlemann Chart for Smoke Opacity Monitoring (b) Dual Beam Method Dual Beam Method is a universally accepted method to monitor smoke opacity. The basic principle of this method is to transmit a light beam through the flue gas (to be tested) and measure the reduction in its intensity. Main components of the system are a twin beam transmitter, a high-intensity light source and detectors. The system arrangement is illustrated in Figure 3. The main issue in this method is locating the monitoring system across the pre defined cross section of the stack at a certain height. [This height is defined to obtain a Laminar Flow Region and the level depends on the system set up]. Further, pre facility requirements to handle the instruments, to monitor/measure the parameters are not incorporated in many existing combustion systems. ENGINEER 4 ENGINEER 54

5 Figure 3 Dual Beam Method Smoke Opacity Monitoring Figure 3 Kit Dual [Source Beam Method Forbes Smoke Marshall Opacity DCEM Monitoring 2100 Unique Kit [Source Dual Beam Forbes Opacity/Dust Marshall Monitor] DCEM 2100 Unique Dual Beam Opacity/Dust Monitor] 3.3 Monitoring of Dioxins and other 3.3 Gaseous Monitoring Components of Dioxins and other The most common Gaseous gaseous Components emissions described in The this most particular common standard gaseous are emissions SO X, & described NO X. However, in this in particular many cases, standard this standard are SO X, has & not NO X. described However, the in marginal many cases, figures this of standard SO X, & NO has X not and described has advised the marginal to control figures those of SOgaseous X, & NO X emissions and has by advised maintaining to control the stack those height & temperature emissions by by maintaining incorporating the stack emission height & reduction temperature utilities. by In addition incorporating to that emission it important reduction to monitor utilities. CO, In CO addition 2, excess to air that levels it is etc. important in flue gas to for monitor efficient CO, combustion CO 2, excess systems. air levels etc. in flue gas for efficient combustion systems Test Methods, Instrumentations and Limitations Test Methods, Instrumentations and In general, Limitations two methods of gaseous components determination, In general, two viz. methods extractive of sampling gaseous components method and determination, non-extractive viz. sampling extractive method, sampling have been method practiced. and non-extractive Out of those sampling two methods, method, extractive have been sampling practiced. method Out of is those the two most methods, common extractive and widely sampling used. method In this method is the most effluent common gaseous and samples widely are used. passed In this through method the moisture effluent gaseous and contaminant samples are absorbent passed through filters to the remove moisture the and moisture contaminant (analysis absorbent under dry filters basis) to and remove to clean the the moisture gas sample (analysis respectively under dry basis) before and being to clean conveyed the gas to sample the instrument. respectively Then before the being conditioned conveyed gas to is the passed instrument. through different Then the chemical conditioned sensors gas (in built is passed sensors) through for necessary different reactions. chemical The sensors composition (in built of sensors) particular for gaseous necessary components reactions. are The measured composition based of particular on the number gaseous of components electrons emitted are measured by different based on chemical the number reactions. of electrons The common emitted system by different arrangement chemical is illustrated reactions. in Figure The common 4. system arrangement is illustrated in Figure 4. Figure 4 Instruments for Exhaust Gas Monitoring Figure 4 Instruments for Exhaust Gas Monitoring The location of sampling points to monitor the gaseous The location concentrations of sampling is not points critical to monitor like in the monitoring gaseous concentrations PM. Because is the not variations critical like of in velocity monitoring profiles PM. do not Because affect the the homogeneity variations of of the velocity gaseous profiles concentration. do not affect This the means homogeneity that the of proximity the gaseous to bends, concentration. branches, obstruction This means by that fans the and proximity dampers to bends, are less branches, important. obstruction But the by sampling fans and after dampers dilution are air less must important. be avoided. But the Therefore sampling monitoring after dilution of gaseous air must parameters be avoided. is convenient Therefore and monitoring can be commonly of gaseous implemented parameters is in convenient many types and of can combustion be commonly systems, implemented since those in do many not types require of any combustion special and systems, expensive since pre-facilities those do not arrangement. require any special and expensive pre-facilities arrangement. 4. Implementation Difficulties of 4. New Implementation & Proposed Environmental Difficulties of Standards New & Proposed Environmental Standards Not only the plant owners or industries, but also regulatory Not only bodies the plant and owners monitoring or industries, parties have but also come regulatory across different bodies and issues monitoring and difficulties, parties have while come implementing across different such issues requirements. and difficulties, Few such while important implementing factors such are discussed requirements. herein Few from such the important point of factors view of are industries/plant discussed herein owners, from third the parties point and of view instrumentation. of industries/plant owners, third parties and instrumentation. ENGINEER 5 ENGINEER 5 55 ENGINEER

6 4.1 Implementation Difficulties 4.1 The implementation Implementation of environmental Difficulties standards The for implementation small & medium of industries environmental is rather standards difficult for compared small & medium with these industries for large is rather combustion difficult compared systems due with to the these under for mentioned large combustion reasons. - systems New standard due to the pre under facility mentioned requirements reasons. such as - New platforms, standard sample pre facility points, requirements safe ladders such as etc. platforms, cannot be sample introduced points, to the safe existing ladders systems etc. cannot due to be structural introduced weakness, to the existing failures, corrosion, systems due space to availability structural weakness, etc. failures, corrosion, - space Low availability income industries etc. cannot bear the high - Low capital income (expenses) industries to cannot modify bear their the existing high capital combustion (expenses) systems to modify to meet their existing standard combustion requirements. systems to meet standard - requirements. Industries that periodically operate (i.e Industries times per that month); periodically especially operate foundry, (i.e. DG 2-4 sets times etc. per will month); have especially to meet foundry, same DG standard sets etc. requirements will have like to other meet continuous same standard operating requirements plants. like other continuous operating - plants. The systems that have been already purchased; - The especially systems the that waste have been combustion already purchased; incinerators, especially crematoria the etc. waste have combustion not incorporated incinerators, with crematoria emission control etc. have devices not and incorporated techniques such with as emission dual chamber, control wet devices scrubbers, and techniques standard such retention as dual time chamber, etc. wet scrubbers, standard retention - time The etc. chimney height can not be extended; - The especially chimney in DG height sets, furnaces, can not kilns, be extended; cupola etc., especially to meet in the DG standard sets, furnaces, requirement kilns, cupola due to etc., the to existing meet the system standard set up, requirement space availability, due to plant the existing performance, system structural set up, space failures availability, etc. plant - performance, structural failures etc. - - Low graded fuel; especially fossil fuels having - Low high graded moisture, fuel; unexpected especially foreign fossil fuels particles having etc. high can moisture, not be controlled unexpected by plant foreign owners. particles etc. - can Expensive not be controlled monitoring by charges plant owners. due to the limited - Expensive number of monitoring charges parties due and to their demand. limited number of monitoring parties and their demand. 4.2 Monitoring Difficulties in View of 4.2 Monitoring Third Parties Difficulties in View of Even Third though Parties the combustion systems are Even incorporated though the with combustion continuous systems monitoring are incorporated facility not, with the third continuous party inspection monitoring and facility recommendation or not, the reports third party are required inspection to confirm and recommendation whether the particular reports are combustion required to confirm systems whether comply with the the particular environmental combustion regulations systems and comply are operated with the below environmental the standards regulations emission and are levels. operated Such below monitoring the standards parties should emission be levels. registered Such under monitoring the Central parties Environmental should be registered Authority. under the Central Environmental Authority. Out of 47 numbers of registered licensees in Out CEA of for 47 numbers the year of 2012, registered only 12 licensees parties; in 5 CEA government for the year organizations 2012, only and 12 parties; 7 private 5 government institutions, organizations have been and involved 7 private in institutions, environmental have monitoring been practices. involved However in environmental many of them monitoring are having practices. capacities However to monitor many fugitive of them air quality are having but they capacities do not have to monitor capacity fugitive to monitor air quality combustion but they emission. do not have Out of capacity those 12 to registered monitor combustion parties, emission. only three Out of government those 12 registered organizations parties, are having only three capacity government to monitor organizations PM and gaseous are having emissions. capacity However, to monitor no one PM has and facility gaseous to monitor emissions. all However, the basic no emission one has parameters facility to highlighted monitor all in the the standards. basic emission parameters highlighted in the standards. Further the under mentioned difficulties are met Further by the monitoring under mentioned parties while difficulties practicing are met the by measurements. the monitoring parties while practicing the - measurements. - Personal safety Personal Instrument safety protection & safety, handling - - difficulties Instrument protection & safety, handling - difficulties - Interferences of modified devices, such as - - moisture Interferences and water of modified vapor devices, released such by wet as moisture scrubbers/wet and water bottom vapor etc. released by wet - scrubbers/wet - Repeatability bottom due etc. to uneven combustion - - [Variations Repeatability of due process to uneven demand combustion during [Variations monitoring] of process demand during - monitoring] - Lack of knowledge under different - - combustion Lack of systems knowledge under different - combustion - High systems expenses required to maintain - - accreditation High expenses laboratory. required to maintain accreditation laboratory. 4.3 Monitoring Difficulties in View of 4.3 Monitoring Instrumentation Difficulties in View of As discussed Instrumentation under the section 3.0, it is As understood discussed that under special the instrumentations section 3.0, it and is understood skill operators that special assistance instrumentations are required and to skill monitor operators the assistance emission are parameters. required The to monitor instruments the recommended emission parameters. for particular The tests instruments are uncommon recommended and expensive. for particular Further, tests some are instruments uncommon and and chemicals, expensive. like Further, opacity meters, some instruments SO X& NO X and reagent, chemicals, heavy like metal opacity detectors meters, etc., SOare X& not NOlocally X reagent, available. heavy metal detectors etc., are not locally available. The emission monitoring instrumentations shall The be emission subjected monitoring an annual instrumentations calibration shall for be accurate subjected and to standard annual measurements. calibration In for this accurate regard, and the particular standard instruments measurements. shall In be this sent regard, to the the principal particular suppliers; instruments most probably shall be out sent of to the the country, principal for suppliers; re calibration most probably and it will out take of the nearly country, 2-3 months. for re calibration and it will take nearly 2-3 months. ENGINEER 6 ENGINEER 6 ENGINEER 56

7 Sudden failures of instruments; such as malfunctioning, sensor failures, physical damages etc. will also affect the regular monitoring practices. 5. Discussion and Recommendations Author has made the under mentioned recommendations through industrial experiences related to exhaust gas monitoring and existing plant behaviors of stationary combustion systems, such as large scale combustion systems, standby generators, industrial boilers & thermic fluid heaters, incinerators and cupolas, furnaces, kilns etc. maintaining a minimum 20 m stack height and fuel quality. Usually, standby generators are not incorporated with such type of taller stacks. Most of the standby generators are having only silencer with 6-8 diameter & 1-5 length (depending on the capacity). Further it is practically impossible to extend or introduce a 20m chimney to the standby generators, since such modifications will directly affect the plant performance. Typical arrangements are illustrated in Figure Large Scale Combustion Systems Almost all the large scale combustion systems have been incorporated with the particulate matter and effluent gas controlling mechanisms, such as bag filters, cyclone separators, wet scrubbers etc. and inbuilt continuous operating emissions gas monitoring systems. In addition to that pre facility requirements such as working platform, lifting arrangements, sampling ports etc. have also been made available for periodical monitoring purposes. Such an arrangement is illustrated in Figure 5. Figure 5 -Pre-Facility Requirements for Large Scale Combustion Systems Therefore implementation of proposed standards for large scale combustion systems is practicable. 5.2 Standby Generators The available standards guide to control PM, SO X& NO X emission of standby generators by Figure 6 - Silencers in Standby Generators In many industries, diesel generators have been used only for the emergency purposes (during the National power failures). Hence the emission released to the environment is comparatively less, because the average operating time and related fuel consumption are less. Therefore the impacts of gaseous emissions to the environment through standby generators are comparatively less. Even though pre facilities are required to monitor PM (normally not available), instrumentations (Pitot tube, nozzle, filter holders etc.) do not match with such types of small stack diameters. However it will not be a practical issue to monitor the opacity level using Ringlemann method in such types of shorter stacks. But monitoring of Opacity will also be an issue, if the stackheight increases up to 20m [Ref. Sections 3.2.1]. ENGINEER 7 57 ENGINEER

8 5.3 Boilers and Thermic Fluid Heaters Boilers and thermic fluid heaters are commonly used combustion systems in industries to obtain thermal energy demand. Almost all the combustion systems in these categories are incorporated with Mild Steel stacks having diameters ranging from 8 to 24 and height ranging from 5m to 10m. Some stacks have been directly extended through the boiler house roof top and the others are extended by the branch connection between boiler and the stack. The arrangements are illustrated in Figure. 7. Figure 7 - Stack Arrangement of Boilers and Thermic Heaters However in many stacks, it is practically impossible to extend the stacks to meet the standard requirements for gaseous emission controlling and to introduce pre facility requirements for PM monitoring. The main reasons found are structural failure, additional space requirements and effects to the draught etc. In addition to that the opacity monitoring by Ringelman method is not practical in many cases due to the similar issues discussed under Section Therefore only solution to monitor exhaust gas emissions of boilers and thermic heaters is to introduce new stacks instead of the existing stacks to meet the standard requirements. 5.4 Waste Combustion Incinerators Waste combustion incinerators are the worst stationary combustion systems among the different combustion systems discussed in this standard. Because, unlike the other combustion systems, not only the fuel combustion emissions, but other harmful gaseous substances from waste combustion also are emitted to the atmosphere. Therefore not only the SO X and NO X, the other toxic gases too have to be monitored in incinerators. [Ref.Table 1.0]. However many incinerators have not incorporated pre facility requirements to monitor either PM, opacity or any other gaseous parameters. Further the systems having water scrubbers and more than 20 m height stacks are rarely found. Even through the emission regulations for waste combustion are stricter than for the other combustion systems, it can be seen that non standardized plants (emitting gaseous pollutants) are being operated island wide. This is basically due to non recommended waste combustion, over charging (waste), employing unskilled operators, mismatched plant specifications (stack height, retention time, number of burners etc.), and incineration temperature etc. The measurement and implementation issues discussed under section 5.3 are also applicable in this category of plants. In addition to that, some stacks are made out of fire bricks and therefore one cannot introduce monitoring pre facility and water scrubbing etc. The arrangement is illustrated in Figure 8. Figure 8 Stack Arrangement of Incinerators Further the instrumentations available to monitor HCl, Mercury, Lead; Dioxin and Furans emission are hardy found. This standard has also guided to monitor the secondary chamber temperature around 1,100 0 C - 1,250 0 C and the retention time is around 2-3 ENGINEER 8 ENGINEER 58

9 seconds to control the Dioxins and Furans seconds emissions. to control Out of the those Dioxins two and monitoring Furans emissions. parameters, Out the of temperature those two can monitoring be monitored parameters, using high the temperature sensors. can be But monitored such type using of high sensors temperature and instrumentations sensors. But such are type not of commonly sensors and available. instrumentations In addition to are that, not there commonly are no any available. practical In methods addition to to ensure that, that there such are plants no any operate practical under methods recommended/designed to ensure that such plants retention operate time. under recommended/designed retention time. Therefore while considering the above Therefore limitations, while the most considering practical method the to above control limitations, emission the from most incinerators practical method is to to introduce control a emission water scrubber from incinerators the system. is to However introduce it is a not water practical scrubber to modify to the system. the existing However incinerators it is not due practical to unlimited to modify number the existing of incinerators design parameter due to variation. unlimited But number permission of design can be parameter given to variation. purchase But or permission set up new can incinerators be given having to purchase water scrubbers, or set up multi new chambers, incinerators standard having stack water height scrubbers, etc. multi chambers, standard stack height etc. 5.5 Cupolas, Furnaces, Ovens and Kilns 5.5 The stack Cupolas, arrangements Furnaces, Ovens under and this Kilns category of The combustion stack arrangements systems are under closely this category similar to of the combustion systems described systems under are closely the sections similar 5.3 to and the 5.4. systems But the described types and under quantity the sections of gaseous 5.3 and emissions 5.4. But depend the types on and the quantity fuel used, of gaseous plants emissions capacities, depend material on process, the fuel and used, operating plants time. capacities, However material some process, processes and under operating this time. category However are not some continuous processes operations under this and category those are are operated not continuous once per operations week or fortnight and those or sometimes are operated once a once month. per week or fortnight or sometimes once a month. Domestic level foundry industry belongs to this Domestic category. level Many foundry plants industry have been belongs operated to this 3-5 category. hrsper Many day and plants 2-4 times have per been month. operated The 3-5 fuels hrsper used day for and Al and 2-4 Cu times melting per month. processes The are fuels burnt used oil for and Al for and the Cu cast melting iron melting processes process are burnt is coal. oil Like and for an incinerator the cast iron not melting only the process fuel combustion is coal. Like emissions, an incinerator but also not impurities only the fuel of melting combustion metals emissions, are mixed but with also the impurities exhaust gases. of melting metals are mixed with the exhaust gases. While considering the operating times per While month, considering the quantity the of metal operating processing times and per the month, amount the of quantity fuel combustion, of metal processing it is not economical and the amount to introduce of fuel combustion, pre facility it requirements is not economical or wet to scrubbing introduce systems pre facility to processing requirements plants or of wet such scrubbing category. systems The arrangement to processing plants is illustrated of such in category. Figure 9. The arrangement is illustrated in Figure 9. ENGINEER 9 ENGINEER 9 Figure 9 - Stack arrangement of Furnaces Figure 9 - Stack arrangement of Furnaces However, out of the parameters mentioned in However, this standard;it out of the is possible parameters to practice mentioned the opacity in this test standard;it using Ringlemann is possible to method. practice the opacity test using Ringlemann method. 5.6 Crematoria 5.6 In this Crematoria standard, it is described that the emission In this from standard, crematoria it is described shall be that the controlled emission by from introducing crematoria emission shall control be controlled devices. by Even introducing though the emission particular controlling devices. Even are not though mentioned, the particular it may controlling be a water devices scrubber. are not But mentioned, introducing it may water be scrubber a water again scrubber. might But be an introducing issue to release water water scrubber with again toxic contaminants might be an to issue the to release environment. water with Therefore toxic contaminants only possible to the solution environment. for crematoria Therefore is to maintain only possible chimney solution height for according crematoria is the to standards. maintain chimney Further in height general, according crematoria the standards. are single Further chamber in general, combustion crematoria system. are Therefore single introducing chamber a combustion secondary system. burner (attached Therefore to the introducing stack) to burn a secondary the exhaust burner toxic (attached gases to at the higher stack) temperature to burn the will exhaust help toxic reduce gases the at Dioxin higher emission. temperature Further will it help is not to possible reduce the to implement Dioxin emission. any toxic Further gases or it is PM not monitoring possible implement procedures any during toxic gases cremation or PM due monitoring cultural/traditional procedures issues. during cremation due to cultural/traditional issues. 6. Conclusion 6. Conclusion The outcomes of this paper will be useful to the The regulatory outcomes of bodies this paper for updating will be useful the proposed to the regulatory emission bodies standards for updating more practical, the proposed flexible, emission and convenient standards in ways. more practical, For an flexible, example, and requirement convenient of ways. separately For categorizing an example, the requirement periodically of operating separately plants categorizing and continuous the periodically operating plants, operating since plants the quantity and continuous of emission operating release plants, to the environment since the quantity are different. of emission Further release the contents to the environment of this paper are will different. help industries Further to the modify contents their of this existing paper systems will help according industries to to the modify new standard, their existing pre facility systems requirements according to etc. the Also new standard, pre facility requirements etc. Also 59 ENGINEER

10 the techniques discussed under measurements will help monitoring parties to update their knowledge under the emission monitoring systems. Finally the author expect contribution from regulatory bodies, industries and monitoring parties to mitigate the environmental impacts by reducing emission release to the atmospherevia stationary combustion systems. Acknowledgement I would acknowledge Engineer D R Pulleperuma, the former Chairman, National Engineering Research & Development Centre (NERDC) for providing his valuable input to make this paper a success. Further I take pleasure in thanking Engineer D D Ananda Namal, the Director General, NERDC, for granting permission to publish this paper. I also appreciate the comments made by the Director of the Renewable Energy Department Eng. Nandana Edirisinghe and Senior Research Scientist (Mrs.) Nayana Pathiraja, of NERDC, to make this paper a Success. 6. Proposed Environmental Standards for Stationary Combustion Sources; Central Environmental Authority, Sri Lanka. 7. KM 9106 Flue Gas Analyzer Operation Manual, Kane International Limited, Kane House, Swallowfield, Welweyn Garden City, Hertfordshire, AL 7 IJG. 8. ENVIROTECH APM 621 Stack Monitoring Kit Operation Manual, VAYUBODHAN UPKARAN (Pvt.)Ltd. A 292/1, OkhlaIndustrial Area Phase 1, New Delhi Sri Lanka Environment Outlook 2009, Ministry of Environment & Natural Resource, United Nations Environment Programme. References 1. International Standards; ISO Stationary Source Emissions Automated Monitoring of mass Concentrations of Particles Performance Characteristics, Test methods and Specifications. 2. International Standards; ISO 7935 Stationary Source Emissions Determinations of the Mass Concentration of Sulfur Dioxide Performance Characteristics of Automated Measuring Methods. 3. International Standards; ISO Stationary Source Emissions - Sampling for the Automated Determination of Gas Concentrations. 4. Technical Guide Not (Monitoring) M I Sampling Requirements for Stack Emission Monitoring; Environment Agency, Version 4, July Technical Guide Note (Monitoring) M 2 Monitoring of Stack Emissions to Air; Environment Agency Version 4, July ENGINEER 10 ENGINEER 60