Determination of S02 Emission from Oil Combustion Sources by Fuel Analyses and S02/C02 Relations

The current S0₂ emission test methods, based on wet chemistry, are time consuming and costly. Final results depend on at least 10 separate measurements of quantities which may introduce significant errors due to human factors especially under unfavorable field environment. Performance evaluation of several promising S0₂ instrumental methods indicated that results were reliable and reproducible, but instrumental problems still exist. The problems were found to be calibration, mechanical and electronic components, and sample conditioning system. An alternative method proposed requires only two separate analyses: ultimate fuel analysis and stack gas analysis for C0₂. This method can be further simplified with reasonable accuracy by a single measurement of sulfur in the fuel if results are corrected to 12% C0₂. The method can be a useful addition to the current methods, especially if cost and manpower preclude actual stack tests. A test program was conducted at four industrial and utility power plants. Results are presented with discussion to show the application and validity of the simplified method.     

Emission measurements of heavy metals with the European standard reference methods EN 14385 and EN 13211—observations from interlaboratory comparison (ILC) measurements performed at waste-to-energy plant in Finland

ABSTRACT

This study presents the heavy metal results obtained during Finnish interlaboratory comparison (ILC) measurements made during 2019. The aim of this measurement campaign was to verify the skills of accredited emission measurement teams and also to evaluate the challenges that stack testing teams face in the future when emission levels decrease. ILCs have been organized in Finland since the 1970s. ILCs provide an important platform for stack testing teams so that they can verify their measurement skills and also for the dissemination of knowledge. The knowledge about the measurement standards and their requirements has improved among stack testing teams during past years in Finland. As emission levels get lower, they still need to pay more attention to some quality assurance procedures, e.g. to method and field blanks. Based on the observations of this ILC for heavy metals it can be noted that the challenges that stack testing teams face are related to the fact that no guidance is given in the standard reference methods EN 13211 and EN 14385 for example on the calculation of measurement uncertainties and how results below limit of quantification should be taken into account. These reference methods were suitable for their purpose at the time they were validated. However, emission levels are now more stringent and it is challenging to measure them with acceptable uncertainty criteria. As a consequence, there is a clear need for harmonized approaches in Europe for consistent implementation of standards and regulations. Key issues where guidance should be provided include realistic measurement uncertainties at low concentration levels, reporting low concentrations and guidance on how measurement uncertainties should be taken into account when the results are used for compliance assessment. The overall aim is to ensure that even with low emission levels, the emission measurement results would be transparent and robust throughout the EU.

Implications: Interlaboratory comparison measurements between stack testing teams are the most important tool to verify the quality of the measurements. Participation in an appropriate ILC is often mandatory to successfully achieve accreditation under ISO/IEC 17025. Such campaigns also provide an efficient platform for dissemination of knowledge. In addition, ILCs can be used to clarify the challenges that teams nowadays face when measuring low emission levels, thus creating important information for the revision work of standards.     

Estimate of the uncertainty in measurement for the determination of mercury in seafood by TDA AAS

An approach for the estimate of the uncertainty in measurement considering the individual sources related to the different steps of the method under evaluation as well as the uncertainties estimated from the validation data for the determination of mercury in seafood by using thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) is proposed. The considered method has been fully optimized and validated in an official laboratory of the Ministry of Agriculture, Livestock and Food Supply of Brazil, in order to comply with national and international food regulations and quality assurance. The referred method has been accredited under the ISO/IEC 17025 norm since 2010. The approach of the present work in order to reach the aim of estimating of the uncertainty in measurement was based on six sources of uncertainty for mercury determination in seafood by TDA AAS, following the validation process, which were: Linear least square regression, Repeatability, Intermediate precision, Correction factor of the analytical curve, Sample mass, and Standard reference solution. Those that most influenced the uncertainty in measurement were sample weight, repeatability, intermediate precision and calibration curve. The obtained result for the estimate of uncertainty in measurement in the present work reached a value of 13.39%, which complies with the European Regulation EC 836/2011. This figure represents a very realistic estimate of the routine conditions, since it fairly encompasses the dispersion obtained from the value attributed to the sample and the value measured by the laboratory analysts. From this outcome, it is possible to infer that the validation data (based on calibration curve, recovery and precision), together with the variation on sample mass, can offer a proper estimate of uncertainty in measurement.     

Comparison of variability in dioxin and furan data acquired using single train and simultaneous multiple train stack sampling methods

The variance of polychlorinated dibenzo-p-dioxin (PCDD; dioxin) and polychlorinated dibenzofuran (PCDF; furan) data obtained from single- and simultaneous multiple train methods was compared. Single train triplicate data were used from 4 stack tests obtained from a long dry kiln cement plant and 18 stack tests from a municipal solid waste (MSW) incinerator. Data from the American Society of Mechanical Engineers (ASME) report Reference Method Accuracy and Precision (ReMAP) (Lanier and Hendrix, 2001) were used for the simultaneous multiple samples, which accounted for 27 data points. Nineteen data points were acquired from an ASME research facility, 5 from a MSW incinerator unrelated to the single train MSW incinerator, and 3 from a lightweight aggregate kiln (LWAK). The ReMAP procedure was used to determine the relationship between the standard deviation and the concentration of the single train and simultaneous multiple train data. Results indicated that there was benefit from the use of simultaneous multiple train sampling for concentrations above 129 pg toxic equivalency (TEQ)/m³. There was no indication of benefit from the use of simultaneous multiple train sampling at concentrations below 129 pg TEQ/m³.

Implications:Precision of stack sampling data can be the difference between meeting and failing compliance limits. Generally, three dioxin/furan samples are acquired when stack sampling to meet compliance regulations. A reliable estimation of the data’s true concentration is not possible with this small amount of data. Increasing the precision decreases the chance that the acquired concentration deviates greatly from the true concentration. Facilities that use the appropriate stack sampling method will benefit by either improved data precision or minimal stack sampling expenses. The observations made suggest that facilities that are expected to have dioxin/furan concentrations above 129 pg TEQ/m³ would increase the precision of samples by using simultaneous multiple train sampling.     

Measuring Inorganic and Alkyl Lead Emissions from Stationary Sources

Described are the results from studies done to provide test methods for state and local air pollution control agencies to measure accurately the lead emissions from stationary source stacks as required in the National Ambient Air Quality Standard for Lead. Separate test methods were developed for measuring inorganic lead and alkyl lead compounds. Inorganic lead is collected in a standard particulate sampling train, digested with 50% (V/V) nitric acid and 3% hydrogen peroxide and analyzed by atomic absorption spectrometry. Alkyl lead compounds are collected in iodine monochloride and analyzed by atomic absorption spectrometry without prior solvent extraction. Standard solutions of inorganic lead in dilute nitric acid are used to calibrate the spectrophotometer in both methods. The inorganic lead test method was evaluated using baghouse dust samples from a primary copper and a primary lead smelter and stack samples from a lead recovery furnace, a primary battery manufacturing plant, a gray iron foundry and a secondary lead smelter. The alkyl lead method was evaluated using alkyl lead motor mix fluids and samples from an alkyl lead manufacturing plant vent stack.     

Linking Fine-Scale Sub-Arctic Vegetation Distribution in Complex Topography with Surface-Air-Temperature Modelled at 50-m Resolution

This article presents the impact of the ecological investment in ironworks (dust filter installation) and construction works at a highly contaminated brownfield site on the chemical composition of household dust (HD) and street sediment (SS) in Celje, Slovenia. The evaluation is based on two sampling campaigns: the first was undertaken 1 month before the ecological investment became operational and the second 3 years later. The results show that dust filter installations reduced the content of Co, Cr, Fe, Mn, Mo, W and Zn on average by 58% in HD and by 51% in SS. No reduction was observed at sampling points in the upwind direction from the ironworks. By contrast, the impact of the construction works on the highly contaminated brownfield site was detected by a significant increase (on average by 37%) of elements connected to the brownfield contamination in SS. Such increase was not detected in HD.     

The Nonlinearity and Related Band Strength of Carbon Monoxide When Applied in Ambient Air Measurement Using Open Long-Path Fourier Transform Infrared Spectrometry

ABSTRACT

The accuracy of CO concentration determination by open-path Fourier transform infrared (FTIR) spectrometry has been re-evaluated in detail. The evaluation focuses on the correction of the calibration curve—the integrated intensity of a standard spectrum—that is used as a comparison spectrum when doing quantitative analysis of CO. Results show that the calibration curve (with 0.5 cm^-1 or 1 cm^-1 resolution) is apparently inclined to be nonlinear under standard conditions, and that the threshold point of nonlinearity is ~0.1 atm-cm. Two commercial FTIR field monitoring systems have been used to investigate the nonlinearity trend. The experimental method consists of using open-path FTIR systems in combination with nondispersive infrared (NDIR) monitors to establish the calibration curve in a semi-closed corridor. The results have been double-checked using closed-cell dynamic equilibrium systems.

When the optical density is larger than a certain value, the curves begin to bend, and when the optical density approaches zero, the band strength is around 178 ± 3 atm^-1 cm^-2 and 173 ± 2 atm^-1 cm^-2, respectively, for 0.5 and 1 cm^-1 resolution at standard temperature and pressure (STP). These values are quite different from other published data that have been acquired by the pressurized method or by high-resolution     

The nonlinearity and related band strength of carbon monoxide when applied in ambient air measurement using open long-path Fourier transform infrared spectrometry

The accuracy of CO concentration determination by open-path Fourier transform infrared (FTIR) spectrometry has been re-evaluated in detail. The evaluation focuses on the correction of the calibration curve--the integrated intensity of a standard spectrum--that is used as a comparison spectrum when doing quantitative analysis of CO. Results show that the calibration curve (with 0.5 cm(-1) or 1 cm(-1) resolution) is apparently inclined to be nonlinear under standard conditions, and that the threshold point of nonlinearity is approximately 0.1 atm-cm. Two commercial FTIR field monitoring systems have been used to investigate the nonlinearity trend. The experimental method consists of using open-path FTIR systems in combination with nondispersive infrared (NDIR) monitors to establish the calibration curve in a semi-closed corridor The results have been double-checked using closed-cell dynamic equilibrium systems. When the optical density is larger than a certain value, the curves begin to bend, and when the optical density approaches zero, the band strength is around 178 +/- 3 atm(-1) cm(-2) and 173 +/- 2 atm(-1) cm(-2), respectively, for 0.5 and 1 cm(-1) resolution at standard temperature and pressure (STP). These values are quite different from other published data that have been acquired by the pressurized method or by high-resolution (<0.006 cm(-1)) spectrometers. It is thought that a higher accuracy is achieved when these new calibration results are used to quantify the CO concentration. The error in concentration determination within 0.1 optical density is less than 2%, and that in the higher optical density region is less than 5%.     

Nomograph for Field Checking Meter Calibrations on EPA-Type Stack Sampling Trains

In a typical "EPA train" for stack sampling, there are two meters, the dry gas meter and the orifice meter, which require periodic calibration. The controversy which presently exists over the required frequency of calibration is the result of using meters which rarely need calibration, but which have the potential of changing calibration at any time.     

A Portable,Battery-Operated,Immediate-Readout Dust-Particle Analyzer

A portable, battery-operated, electro-optical dust analyzer operating on the principle of light scattering from individual dust particles in air drawn through a high-intensity light field has been developed for monitoring dust levels where external power may be unavailable. The instrument counts and size-discriminates airborne particles over two size ranges upwards of 0.3 microns with immediate readout. A dilution mechanism permits analysis of particulate concentrations as high as 2400 particles/cm³ on each channel. The self-contained Ni-Cd batteries are rechargeable. Total weight, including batteries and all components, is approximately 14 Ib. Total power used, mainly for pumping a filtered air sheath at 300 cm/sec and for the light source, is less than 34 watts. Another unique feature is the flow system designed for turbulence suppression.

Electronic calibration in terms of number of particles/cm³ for each size range is accomplished in the laboratory by means of a pulse generator with respect to which the readout indicator is calibrated for count. The input voltages to the pulse-height discriminators are appropriately attenuated for various pulse amplitudes simulating the output of the light-sensitive pickup, a photomultiplier tube.Pulse height as a function of particle size was measured for polystyrene latex beads ranging from 0.3 to 2 microns in diameter. Good correlation is obtained with results from commercial analyzers.

Field surveys have been undertaken with the CAES prototype analyzer at various sites in central Pennsylvania and at numerous sampling points within the cities of Pittsburgh and Philadelphia. Particulate concentrations as high as 1400 particles/ cm³ have been measured at a coal cleaning plant.     

Comparison of stack measurement data from R&D facilities to regulatory criteria: A case study from PNNL

Chemical emissions from research and development (R&D) activities are difficult to estimate because of the large number of chemicals used and the potential for continual changes in processes. In this case study, stack measurements taken from R&D facilities at Pacific Northwest National Laboratory (PNNL) were examined, including extreme worst-case emissions estimates and alternate analyses using a Monte Carlo method that takes into account the full distribution of sampling results. The objective of this study was to develop techniques to estimate emissions from stack measurement data that take into account a high degree of variability in the actual emissions. The results from these analyses were then compared to emissions estimated from chemical inventories. Results showed that downwind ambient air concentrations calculated from the stack measurement data were below acceptable source impact levels (ASILs) for almost all compounds, even under extreme worst-case analyses. However, for compounds with averaging periods of a year, the unrealistic but simplifying extreme worst-case analysis often resulted in calculated emissions that were above the lower level regulatory criteria used to determine modeling requirements or to define trivial releases. Compounds with 24-hr averaging periods were nearly all several orders of magnitude below all, including the trivial release, criteria. The alternate analysis supplied a more realistic basis of comparison and an ability to explore effects under different operational modes.

Implications:

Air emissions from research operations are difficult to estimate because of the changing nature of research processes and the small quantity and wide variety of chemicals used. Stack measurements can be used to verify compliance with applicable regulatory criteria. This study shows that while extreme worst-case assumptions can be used for a relatively simple initial comparison, methods that take into account the full range of measurement data are needed to provide a more realistic estimate of emissions for comparison to regulatory criteria, particularly those criteria that define trivial levels of environmental concern.     

Studies into the formation of dioxins in the sintering process used in the iron and steel industry. 1. Characterisation of isomer profiles in particulate and gaseous emissions

Dioxin analyses using a DB5MS chromatography column are presented for samples of dust from an electrostatic precipitator and emissions from the main stack of a UK sinter plant. The analyses have been repeated using the SP2331 column, for which the elution order has been determined for the whole range of tetra to octachlorodibenzo-p-dioxins and dibenzofurans, and which provides a larger degree of separation than the DB5MS column. Polychlorinated dibenzofurans are present in significantly larger amounts in both the dust and stack emissions, and are the main contributors to the I-TEQ. Analysis using the SP2331 column for dioxins show considerable similarity to those of Bacher et al. for soot from a wood-burning fire, but differ markedly from those of Addink et al. for simulation of waste incineration. The similarities to Bacher's results are less for the dibenzofurans. Comparison of absolute concentrations with reported vapour pressures shows the retention of significant dioxin in the dust to involve mechanisms other than pure condensation.     

Detection of Asian dust (Hwangsa) over the Yellow Sea by decomposition of unpolarized infrared reflectivity

The periodical occurrence of Asian dust (Hwangsa) in East Asia during every spring and winter is of great consequence to regional human health and visibility. One weakness of the previous methods based on the brightness temperature (BT) differences or optical depths is that they can not accurately detect the dust events over the Yellow Sea. This study proposes a unique technique of decomposing unpolarized reflectivities to distinguish between dust and clouds over the sea surface. Many current infrared (IR) satellite instruments such as MTSAT-1R measure the unpolarized radiance. In this process, an approximate relationship between vertically and horizontally polarized reflectivities is validated for the IR wavelengths of 3–12 μm. The radiances observed from an IR geostationary satellite and the simulated sea surface temperature (SST) are used for a case study of Asian dust events. The results show qualitatively the reasonable spatial agreements with MODIS true color images for these Asian dust events. The proposed method in this study can be utilized for the operational purpose to detect the signal of Asian dust over sea surface.     

Zinc acclimation and its effect on the zinc tolerance of Raphidocelis subcapitata and Chlorella vulgaris in laboratory experiments.

The effect of zinc acclimation of Raphidocelis subcapitata (syn. Selenastrum capricornutum) and Chlorella vulgaris on their sensitivity towards this metal was examined in a series of laboratory experiments. These two commonly used algal species were acclimated to 65 microg Zn/l and changes in zinc tolerance were monitored using standard growth inhibition tests. The chemically defined ISO medium was used as a control culture medium. Both species demonstrated a maximum increase in zinc tolerance of a factor of 3 after 100 days of acclimation. Shifts in the shape of the concentration-response curve due to acclimation were observed for R. subcapitata. Compared to non-acclimated algae, acclimated R. subcapitata exhibited higher growth rates in all zinc treatments as well as in the controls. This suggests that the use of ISO-medium results in sub-optimal growth due to zinc deficiency. These effects could not be demonstrated for C. vulgaris. The zinc tolerance of both species decreased significantly one week after returning the acclimated algae to control (ISO) medium. 72hEC50 values based on growth rate were two to four times higher than those calculated using biomass measurements. Algal toxicity test results, particularly if used for metal risk assessments, must not be conducted using nutrient deficient media.     

Comparison of concentration/flux ratios measured with a backscatter Lidar and with a chemical tracer

A series of backscatter Lidar measurements were made around a bio-waste power station at Eye in Suffolk over a period of 10 days in May 1999. These measurements were supplemented with bag samples of SF₆ tracer, analysed on site using gas chromatography with an electron capture detector. Despite problems with contamination, a detection limit of 20 ppt was eventually achieved and this permitted useful plume measurements from a release rate of 1–2 l min⁻¹. Concentration/flux ratios were estimated from the Lidar measurements using an integral technique. Of the Lidar runs obtained, 24 were coincident with a tracer release. After allowing for the background of both aerosol and tracer, it was apparent that the independent calibrations of concentration/flux ratio from Lidar or tracer agreed with each other to within 20–60%. This permits the Lidar scans to be used to estimate peak near-ground concentrations, though because of various technical difficulties (poor alignment, background sources of aerosol, or an inconvenient wind direction) this cannot always be achieved. Besides giving confidence in the Lidar calibration, the tracer measurements were valuable in permitting aerosol from the stack to be distinguished from aerosol from fugitive sources. Meteorological parameters were logged simultaneously with the dispersion measurements. These parameters included conventional means of wind speed and direction, temperature, humidity and insolation, and also micrometeorological measurements of turbulence and of turbulent fluxes. The Lidar was used to estimate wind speed and direction at plume height and the boundary layer depth and cloud-base where possible. Source emission characteristics were also logged.     

Thermal destruction of wastes containing polychlorinated naphthalenes in an industrial waste incinerator

A series of verification tests were carried out in order to confirm that polychlorinated naphthalenes (PCNs) contained in synthetic rubber products (Neoprene FB products) and aerosol adhesives, which were accidentally imported into Japan, could be thermally destroyed using an industrial waste incinerator. In the verification tests, Neoprene FB products containing PCNs at a concentration of 2800 mg/kg were added to industrial wastes at a ratio of 600 mg Neoprene FB product/kg-waste, and then incinerated at an average temperature of 985 °C. Total PCN concentrations were 14 ng/m³N in stack gas, 5.7 ng/g in bottom ash, 0.98 ng/g in boiler dust, and 1.2 ng/g in fly ash. Destruction efficiency (DE) and destruction removal efficiency (DRE) of congener No. 38/40, which is considered an input marker congener, were 99.9974 and 99.9995 %, respectively. The following dioxin concentrations were found: 0.11 ng-TEQ/m³N for the stack gas, 0.096 ng-TEQ/g for the bottom ash, 0.010 ng-TEQ/g for the boiler dust, and 0.072 ng-TEQ/g for the fly ash. Since the PCN levels in the PCN destruction test were even at slightly lower concentrations than in the baseline test without PCN addition, the detected PCNs are to a large degree unintentionally produced PCNs and does not mainly stem from input material. Also, the dioxin levels did not change. From these results, we confirmed that PCNs contained in Neoprene FB products and aerosol adhesives could be destroyed to a high degree by high-temperature incineration. Therefore, all recalled Neoprene FB products and aerosol adhesives containing PCNs were successfully treated under the same conditions as the verification tests.     

Measurement of Opacity and Particulate Emissions with an On-Stack Transmissometer

An on-stack transmissometer system which is designed to provide a precision measurement of the opacity of visible emissions is described. The sources of error in opacity measurements with regard to recent EPA emission monitoring requirements and planned specifications are discussed. Sources of error are voltage changes, temperature changes, light source and detector aging and effects of ambient light. Other major operational errors are caused by alignment drift and soiling drift. The methods employed to minimize these errors achieve an accuracy of ±3% of span and a maintenance free operational period of 3 months. The relationships between optical density, opacity and transmittance are described. The instrument measurement can be correlated with dust loading provided the particle size distribution is constant. Examples are given of correlations obtained between optical density and particulate concentration in the gas on various types of emission sources and the observed error margins are summarized.     

以废纸为原料制备煤尘抑制剂的合成及应用

采用碱化、醚化法制备了以废纸为原料的煤尘抑制剂,借助FTIR、SEM、TG-DTA及XRF等手段对合成物进行了表征,并将其用于抑制煤尘进行性能测试。结果表明,羧甲基纤维素的取代度为0.69;选用羧甲基纤维素含量为0.5g/mL的煤尘抑制剂进行应用实验,效果最佳。9 h内,喷洒含有羧甲基纤维素的煤尘抑制剂的煤样表面已经结壳,抗七级风,抑尘率在130 h都可保持在99%以上。在较高温燃烧条件下,煤尘抑制剂以H2O和CO2的形式失去,不会产生有害物质。     

Comparison of measurement methods for the characterization of the black carbon emissions from a T63 turboshaft engine burning conventional and Fischer-Tropsch fuels

Emission measurements of black carbon (BC) mass were conducted on a T63 turboshaft engine, operated at idle and cruise power with conventional and alternative fuels, using an Artium LII-300 laser-induced incandescence analyzer (LII) and AVL model 483 micro soot sensor (MSS) photoacoustic instrument using the manufacturer’s calibration for both instruments. These measurements were compared with elemental carbon (EC) determined by manual and semicontinuous thermal-optical transmission analyses according to National Institute for Occupational Safety and Health (NIOSH) method 5040 as the reference method. The results indicate that both the LII and MSS instruments show good linear correlation with EC for the two fuels and two engine power conditions evaluated. The LII measurements were observed to be biased high (27–49%) and the MSS measurements were biased low (24–35%) relative to EC. The agreement between the instruments and the reference method was substantially improved by applying a calibration of the instruments against a common BC aerosol source. Test data also suggest that the two instruments show some sensitivity to particle size (or properties related to size), specifically for particles with a geometric mean diameter (GMD) <30 nm. This sensitivity is problematic, since new engines or certain combustion conditions in current engines will produce smaller particles compared with the T63 model tested in this study. Further assessments of instrument performance for particles within this size range are therefore warranted.

Implications: Accurate black carbon emission measurements are needed to certify new and in-production commercial aircraft engines. Both the Artium LII-300 and AVL 483 micro soot sensor are currently approved by the International Civil Aviation Organization for this purpose. This study compares the two instruments against elemental carbon (EC) using NIOSH method 5040 as the reference using a T63 turboshaft engine. The results indicate that both instruments correlate reasonably well with EC, and the correlation substantially improved when applying a calibration against a common aerosol source. Sensitivity to particle size may be an issue for both instruments.