Analyzer underpins growth of container inspection company.

10/02/2017

After a career as a customs officer in the Netherlands, Wim van Tienen was well aware of the toxic gas hazards presented by some freight containers, so in 2009 he started a company, Van Tienen Milieuadvies B.V., offering gas analysis and safety advice. The company grew quickly and now employs 23 staff. Wim attributes a large part of this success to the advanced FTIR gas detection and analysis technology upon which the company’s services depend.

Background

Wim van Tienen

Wim van Tienen

It has been estimated that there are more than 17 million shipping containers in the world, and at any time about one third of them are on ships, trucks, and trains. Over a single year, the total number of container trips has been estimated to be around 200 million.

The air quality inside containers varies enormously, depending on the goods, the packing materials, transit time, temperature, humidity and the possible presence of fumigants. Consequently, many containers contain dangerous levels of toxic gases and represent a major threat to port and transport workers, customs officials, warehousemen, store employees and consumers. It is therefore essential that risks are assessed effectively before entry is permitted.

Solvent vapours and most fumigants, whilst harmful, can be detected by the human nose, but Wim says: “Some gases are odourless and some have a high odour detection threshold, which means that you can only smell the substance in high concentrations; ethylene oxide for example, is commonly used as a sterilant in relation to medical devices. It is extremely toxic and has a low TLV limit of 0,5 ppm. However the odour threshold limit of ethylene oxide is 500 ppm, so detection with instrumentation is essential.”

The wide variety of potential contaminants represents a technological challenge to those responsible for testing, because if testers seek to detect specific gases, they risk failing to detect other compounds. It is also not practical to test every single container, so logical procedures must be established in order to minimise risks.

Gas Detection and Measurement
In 2009, when Wim first established the company, container gas detection was carried out with traditional field measurement techniques (gas detection sensors and tubes). “This approach was complicated, costly and time-consuming, and it was impossible to cover all risks,” he says. “With sensors and tubes, only a limited number of compounds can be measured specifically. Furthermore, the accuracy of detection tubes is poor and they can suffer from cross-sensitive reactions by interfering substances.

“Technologies such as PID-detectors respond to a wide variety of organic compounds, but they are not selective and unable to detect commonly found substances with high ionisation potentials such as 1,2-dichloroethane and formaldehyde.” Wim does not, therefore, believe that traditional measurement techniques are the best approach for covering all risks. “In order to test for the most common gases, it would be necessary to utilise a large number of tubes for every container, but this would still risk failing to detect other compounds and would be very expensive.

“It is possible to speciate organic compounds when using a Gas Chromatograph, but the number of compounds that can be tested is limited, and the use of a GC necessitates frequent calibration with expensive standard gases.”

Simultaneous multigas analysis
As a result of the problems associated with traditional gas detection techniques, Wim was keen to find an alternative technology and in 2013 he became aware of portable FTIR multigas analyzers from the Finnish company Gasmet Technologies. “The Gasmet DX4040 appeared to be the answer to our prayers,” Wim says. “The instrument is able to both detect and measure hundreds of compounds simultaneously; with this technique all inventoried high risk substances, such as ethylene oxide and formaldehyde, are always measured in real-time.

“With the help of Peter Broersma from Gasmet’s distributor Reaktie, a special library of over 300 gases was developed for our container monitoring application, and 8 Gasmet DX4040 FTIR instruments are now employed by our team of gas testing specialists.”

The major advantage of the Gasmet FTIR analyzers is the simultaneous multigas analysis capability. However Wim says: “Our testing work is now much faster, efficient and cost-effective, not least because the analyzers are small, lightweight, relatively simple to run, and no calibration is required other than a quick daily zero check with Nitrogen.”

Van Tienen Milieuadvies also employs a fully trained and highly qualified chemist, Tim Gielen, who is able to conduct in-depth analysis of recorded FTIR spectra when necessary. This may involve comparing results with Nist reference spectra for over 5000 compounds.

Most of the gases that are detected and measured by FTIR analyzers are cargo related. Wim says: “Off-gassing during shipment is the greatest problem, producing VOCs such as Toluene, Xylenes, MEK, 1,2 dichloroethane, blowing agents such as isopentane, and butanes from the packing materials and products.

“Formaldehyde, which evaporates from glued pallets, is most commonly found. On the other hand, less frequently found fumigants, such as sulfuryl difluoride and hydrogen cyanide are also always monitored with our FTIR analyzers.”

Container management
The need for container gas testing is driven by employers’ duty of care for employees, which is embedded in international health and safety regulations. Companies receiving containers must investigate whether employees that open or enter containers, may be exposed to the dangers of suffocation, intoxication, poisoning, fire or explosion. In order for employers to protect staff from these hazards, a risk assessment is necessary, coupled with an effective plan to categorise and monitor container flows. “This is how we develop an effective testing strategy,” Wim explains. “If a flow of containers from the same source containing the same goods and packing materials is found to be safe, the number of containers being tested within that flow can be reduced. Similarly, if toxic gases are identified regularly in a container flow, the frequency of testing will be increased.”

Once a container has been found to contain toxic levels of a gas or gases, it is necessary for that container to be ‘de-gassed’ which is a service that Van Tienen Milieuadvies provides. The process involves fitting a powerful ventilator to the door and capturing the gases with activated carbon. Once degassing is complete, it is important that the container is unloaded promptly, because the gases involved will re-accumulate quickly in a closed container, resulting in the need for repeat testing.

With the benefit of many years of experience, Wim estimates that around 10% of containers contain toxic gases. “This means that hundreds of thousands of containers are travelling the world, representing a major risk to anyone that might enter or open them, so it is vital that effective testing strategies are in place wherever that risk exists.”

“FTIR gas analysis has benefited this work enormously. For us, the main advantages are speed and peace of mind – we are now able to test more containers per day, and by testing for such a large number of target compounds, we are able to dramatically lower the risks to staff. The speed with which we are now able to test containers, coupled with the negligible requirement for service, calibration and consumables, means that the ongoing cost of monitoring is minimal.

“Van Tienen combines the Gasmet DX4040 measurements with risk analysis, which provides the best protection for staff responsible for opening containers. We have LRQA certification for the procedures that we have developed to demonstrate compliance with occupational health and safety legislation.

“Risk analysis provides cost reduction for our clients, due to the fact that measurement frequencies in safe flows can be reduced significantly. Root cause analysis is also part of our risk analysis.”

Looking forward Wim believes that the use of Gasmet FTIR will expand rapidly around the world as the risks associated with containers become better understood, and as employers become more aware of the advantages of the technology.

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Innovation drives flue gas treatment.

08/11/2016
Working closely with Gasmet’s Belgian Distributor, Kelma NV, Lhoist has developed laboratory, pilot scale and mobile process monitoring capabilities to evaluate FGT products that are still in the development phase or to demonstrate the effectiveness of existing FGT products at customers’ sites.
lhoistpilotA business strategy with a heavy focus on innovation has enabled Lhoist, a family owned Belgian company, to become one of the world’s leading providers of Flue Gas Treatment (FGT) products and solutions. In this following article, Johan Heiszwolf, Lhoist’s R & D Director for environmental applications and Antti Heikkilä from gas analyser manufacturer Gasmet Technologies explain how Lhoist’s continual investment in innovation has led to impressive growth in a variety of market sectors, including FGT.

Sharing a common goal, experts in emissions monitoring and emissions abatement have formed a working partnership to develop innovative new materials for treating pollutants in flue gas emissions.

Lhoist history
Lhoist’s roots go back to 1889 when Hippolyte Dumont opened a factory in Belgium. Since that time, the firm has spread internationally: first to France in 1926 on the impetus of the founder’s son-in-law, Léon Lhoist, who further developed the company by acquiring lime, limestone and dolomite plants in Belgium and France. Today, Lhoist is a world leading producer of lime, dolime and minerals, with facilities across Europe, the Americas and Asia.

Over the past 35 years, Lhoist’s production has grown significantly and Lhoist now operates more than 100 facilities in 25 countries, with around 6,000 employees of around 40 nationalities.

Lime, clay and the derivatives of these materials are used in an extremely broad spectrum of industries including agriculture, construction, oil and gas, chemicals, glass, metals and environmental protection including water, wastewater and FGT.

The FGT market has grown considerably in recent decades as a result of higher environmental standards and the development of regulations that imposed emissions limits on industrial processes. These regulations have also driven growth in Gasmet’s business as process operators around the world have sought to monitor multiple gases simultaneously with FTIR analysers in order to demonstrate compliance with emission limits.

One of the reasons for the diversity of Lhoist’s markets is the company’s focus on innovation. Just outside Brussels, the company has established a ‘Business Innovation Centre’ (BIC) which is known as a ‘360 degree talent incubator’ because many of the group’s new recruits spend time at the BIC in order to learn about the group’s culture and its core competencies. Focusing on Research & Development, Intellectual Property, and Strategic Marketing, the BIC staff come from 15 different nations and are given time to spend ‘scouting’ for new scientific solutions to commercial challenges. This strong focus on inorganic and application research is one of the ways in which Lhoist retains its position as a leader in key markets and ensures that innovation continues to drive the growth of the company.

FGT Research
One of the first product groups to be developed by the Lhoist BIC was Sorbacal® which is employed for the removal of major acid pollutants (SOx, HCl and HF) in gaseous emissions from combustion plants such as power stations and incinerators. A number of different products within the Sorbacal® range were developed to meet the needs of different processes. For example, particles of Sorbacal® SP/SPS have a much larger surface area and pore volume in comparison with standard hydrated lime, so this product is employed in applications that require enhanced performance.

An enormous number of tests have to be undertaken to evaluate potential new products and in the case of FGT, the effectiveness of candidate products to remove pollutant gases is key. The BIC laboratory therefore developed a capability to generate artificial flue gas mixtures containing acid gases (SO2 and HCl) in a mixture of N2, O2, CO2, H2O and NOx. The gas composition of this artificial flue gas was tightly managed with mass flow controllers in order to ensure an accurate comparison of pre- and post-treated gas for each product under evaluation.

Different gas analysers were initially used to measure different gases. For example, an InfraRed analyser was used to measure SO2, but for this instrument it was necessary to remove moisture from the sample gas before analysis and some SO2 was lost from the sample as a result. “This complicated the work and incurred delays,” comments Alain Brasseur, Lhoist FGT Senior Research Engineer. “It was also necessary to operate a separate bench for HCl, which further extended the time taken for the tests and introduced a higher possibility of experimental error. A key advantage of FTIR is that it measures both SO2 and HCl, and does so without removing water from the sample.”

Bart De Backer from Gasmet’s local distributor Kelma was therefore contacted and asked to provide information on multigas monitoring with FTIR, which led to the utilisation of a Gasmet DX4000 analyser within the BIC laboratory. At the same time, the staff developed an automated system for running the test unattended, and as a result of the FTIR’s ability to monitor multiple gases in almost real-time in conjunction with test automation, the throughput of the laboratory was increased 10-fold. “The use of Gasmet FTIR gave us a greater insight into the characteristics of the sorbent and facilitated a major step forward in our development programme,” comments Alain Brasseur. “By dramatically increasing the throughput we were able to evaluate a larger number of samples in a shorter period of time, which enabled us to discount those products that failed to meet the required levels of performance at an early stage.”

The laboratory trials effectively assess the intrinsic capacity of the sorbents and if they perform well, the assessment process is continued in a pilot plant to evaluate performance under simulated operating conditions. The pilot plant was also developed by the Lhoist BIC, and is capable of generating a mixture of gases and steam at 180 Deg C to mimic aggressive emissions. The pilot plant is also able to measure sorbent performance under dynamic conditions with varying gas concentrations and temperature.

The pilot plant consists of two separate units – each capable of generating dynamic emissions across a broad range of conditions. The emissions from the older of the two units are monitored with a Gasmet DX4000 heated multigas FTIR analyser. A new pilot unit is monitored by Gasmet’s fixed Continuous Emissions Monitoring System (CEMS) which analyzes gas both before and after treatment using a heated switch-over system.

In addition to the chemical characteristics of the sorbent, Lhoist also places a heavy emphasis on its physical characteristics. For example, the grains of a dry powder product have to be fine enough to be reactive, but not too small to negatively impact the flow behavior of the powder.

In addition to the laboratory and pilot plant facilities, Lhoist has also developed a mobile system that is able to operate at customer sites. Historically, this necessitated the deployment of a large truck, but thanks to the compact nature of the portable FTIR analysers, this is no longer necessary; KELMA has supplied two Gasmet DX4000 portable FTIR analysers in customised rugged transport cases so that the monitoring equipment can be quickly and simply shipped around the world to customer sites. The FTIR analysers can even be operated completely remotely at a customer site. For example in a recent trial two FTIR analyzers, measuring inlet and outlet gas composition, were installed in a plant in the USA while they were monitored remotely from Belgium. The experts from KELMA could log-in to the FTIR analyzers and could perform a software update and calibration.

Onsite monitoring is conducted by Lhoist technical support teams to:

  • demonstrate the enhanced performance of the Sorbacal® products
  • show customers how to maximise treatment efficiency
  • help customers troubleshoot abatement issues

The benefits of onsite demonstrations are considerably advanced by the capabilities of FTIR gas analysis.

Advantages of FTIR gas analysis
FTIR (Fourier Transform InfraRed) is a sophisticated technology for analysing sample gases both qualitatively and quantitatively. The key feature of these instruments is their ability to monitor multiple compounds simultaneously. The Gasmet FTIR analysers are capable of measuring almost any gas and have been developed over many years specifically for the emissions monitoring market. This means that they are extremely rugged and work reliably in both fixed and portable versions. However, a key benefit for environmental applications is their ability to analyse hot, wet, aggressive gas mixtures.

All of the company’s FTIR instruments, fixed and portable, contain exactly the same core analyser which means that they can be operated with the same software, no extra training is necessary and results are directly comparable.

Using Calcmet™ software users of Gasmet analysers are able to analyse sample spectra, producing almost real-time data for pre-selected compounds. However, the retention of recorded spectra offers an opportunity to identify ‘unknowns’ by comparison with reference spectra, and to analyse recorded spectra retrospectively for compounds that were not necessarily of interest at the time of the measurement. For example, Lhoist now includes SO3 in many of its measurements and now has the ability to study measurements for this compound from readings that were taken in the past. This highlights an important advantage of FTIR – when it becomes necessary to measure new compounds, because of new legislation for example, no extra hardware is necessary, so the additional costs are negligible.

In contrast with many traditional gas analysers, the Gasmet FTIR instruments do not require periodic recalibration. A daily background spectrum measurement with zero gas (nitrogen) is enough to preserve measurement accuracy. Instead of periodic span calibrations, reference spectra for analysed gases are measured at the factory when the instrument is made and these do not drift.

From Lhoist’s perspective, Alain Brasseur says: “The ability to work with wet, corrosive gases is obviously a major advantage, and since we routinely analyse over 10 gases, monitoring is much less complicated now that we can do so with just one analyser.

“The size of the Gasmet analysers is also a major advantage for us – they fit neatly into the automated testing system which is installed in a normal lab fume cupboard, and the portable equipment is easy to transport to remote customer sites.

“We have found the instruments to be extremely reliable, requiring minimal maintenance. Also, the support from Gasmet and Kelma has been extremely good and the facility to connect to overseas instruments from Brussels via the internet has been a significant benefit.”

In summary, the evolution of Lhoist’s FGT products has been made possible by giving a talented pool of international experts the freedom to innovate and by working in partnership with like-minded technology leaders such as Gasmet.

@Gasmet_Tech #PAuto #Sorbacal #Lhoist

A fascinating story: Trash to gas project to help life on Mars!

30/11/2014
If you are travelling to Mars on a journey that will last for several months, you need to maintain good breathing air quality and you need to manage your resources very carefully. This article describes research on the off-gases from astronaut waste; checking that they are not harmful and figuring out if they can be converted into water, oxygen and rocket propellant.

As part of a project to measure the effects of long-term isolation on astronauts, small groups of individuals have been selected to live in a tiny ‘Habitat’ perched on the upper slope of a volcano in Hawaii. In doing so, the project team has contributed to the understanding of issues that would confront a manned mission to Mars.

NASA’s Anne Caraccio analyzing waste gases during simulated Mars mission

NASA’s Anne Caraccio analyzing waste gases during simulated Mars mission

For example NASA’s Anne Caraccio studied off-gases from the crew’s trash with a portable Gasmet FTIR gas analyzer. “Waste from the crew’s everyday activities are routinely sorted and stored, but we need to know the composition of the off-gases from these materials for health and safety reasons, and also to determine whether these gases could be utilised beneficially,” Anne reports.

The work was undertaken during the second of four HI-SEAS (Hawaiʻi Space Exploration Analog and Simulation) missions which involved living with 5 other crew members for a period of 120 days in a two-story solar powered dome just 11 metres in diameter with a small attached workshop the size of a shipping container. In addition to the completion of a range of tasks that were set by the project, each crew member conducted their own research, which in Anne’s case was known as ‘Trash to Gas’, a programme working on the development of a reactor to convert waste from long-duration missions into useful commodities such as water, life-support oxygen and rocket propellant.

The main objective of the second HI-SEAS mission was to evaluate the performance and the social and psychological status of the crew members whilst they lived in cramped isolated conditions in a lava rock environment that resembled Mars.

Crew members were allowed outside of the Habitat, but in order to do so they had to wear simulated spacesuits and undergo a 5 minute mock compression/decompression. Since the FTIR gas analyser is portable (14Kg), Anne was able to conduct additional monitoring both inside and outside the Habitat in order to compare data with the waste off-gas measurements. “Size, weight and portability are obviously of major importance on a project such as this, but the main advantage of this technology was its ability to measure a large number of compounds simultaneously; I measured 24 VOCs such as acetaldehyde, methane and ethylene, but the instrument also stores spectra for the measurements so it is possible to retrospectively analyze data if it becomes necessary to look for a particular compound at a later stage.”

Anne’s monitoring provided a clear view of the most important gases within the Habitat. For example, stored waste had the highest relative levels of ethanol (due to crew members’ hygiene wipes and cleaning products) and water vapor (due to residual water from food and plant waste). The laboratory where plants were growing had the lowest relative level of methane. The waste bins had higher relative levels of nitrous oxide and pentane, and the bathroom had the highest levels of acetaldehyde.

The FTIR gas analyser, a DX4040, was supplied by the company Gasmet Technologies. “We were very pleased to be able to help with this project,” says Gasmet’s Jim Cornish. “The simultaneous monitoring of multiple compounds is a common application for our FTIR analyzers, however, they are usually employed measuring gases in stack emissions, industrial processes, greenhouse gas research and in hazmat scenarios. We usually tell prospective customers that advanced FTIR technology is simple to use; ‘it’s not rocket science’ we tell them, so I guess we will have to rephrase that now.”

The waste produced during the HI-SEAS mission was measured during the entire mission, although this was for a shorter period than would be expected of an actual long duration mission. The Trash-to-Gas reactor processed HI-SEAS waste simulant at the Kennedy Space Center with results demonstrating that a future reactor would be most efficient with specific material processing cycles to maximize the desired output. Automation will also be needed in the future Trash-to-Gas reactor because the current technology would require too much of a crew member’s logistical time. The Trash-to-Gas reactor first converts waste into carbon dioxide, which is then mixed with hydrogen in a Sabatier reaction to produce methane and water.

The Kennedy Space Center Trash-to-Gas reactor processed three waste types and produced 9% of the power that would have been needed during the HI-SEAS mission. As part of the psychological assessment, each member of the crew completed regular surveys and kept diaries. They also wore ‘sociometric’ badges that recorded conversation patterns and voice tone.

Commenting on the psychological results of the project, Anne says “The crew were essentially strangers when they entered the Habitat, which is unlike a typical space mission in which the crew would have worked and trained together for a number of months or even years. Nevertheless, the crew coped extremely well with living and working in such close proximity, and there were no significant periods of stress in my opinion.”

The third Hi-SEAS mission began on October 15, 2014. Again, a 6 member crew will conduct a similar mission, with the exception that it will last for 8 months. Anne says: “Participation in these missions requires a real passion for science, technology and space travel. The application process includes a class 2 flight medical, a personal research project proposal, essays, interviews and educational requirements, all of which is similar to the NASA astronaut application procedure.” Looking forward, she says: “The technology to travel to Mars has not yet been fully developed, but it is anticipated that a human mission could be possible in the future. The journey to Mars would take around one year, so I hope that our Trash-to-Gas research will contribute to the science that could make such a mission possible.”


Continuous Mercury monitoring benefits cement plants.

15/05/2014
Antti Heikkilä from Gasmet Technologies highlights the challenges faced by mercury monitoring in cement kilns, and explains how a new continuous mercury monitoring system addresses these issues and provides process operators with an opportunity to improve environmental performance and demonstrate compliance with forthcoming legislation.

Background
The production of cement klinker and lime in rotary kilns is responsible for 10.7% of mercury emissions to air (3,337 kg) according to a recent study. Most of the mercury and mercury compounds pass through the kiln and preheater; they are only partly adsorbed by the raw gas dust, depending on the temperature of the waste gas. For these reasons, monitoring and controlling emissions of mercury to air is important and steps are being taken in several countries to impose emission limits. In the European Union BREF guidance for Cement kilns (CLM BREF), mercury has a BAT-associated emission level of 0.05 mg/Nm3 (50 µg/Nm3) for the half-hour average.

New monitoring technology

Figure 1

Figure 1

Gasmet Technologies has launched a new continuous mercury emission monitoring system (CMM) based on the cold vapour atomic fluorescence (CVAF) measurement principle. The analyser is integrated in an air conditioned cabinet together with a vacuum pump, an automatic calibrator and a nitrogen gas generator. The sample gas is extracted from the process duct with a dilution probe and heated sample line specially designed for sampling mercury from harsh process conditions (see figure 1 right). The analyser has a detection limit of 0.02 µg/Nm3 and the lowest measuring range for total mercury concentration is 0 – 10 µg/Nm3 when a dilution rate of 1:50 is used in the sample extraction probe.

Since the CMM analyser employs a CVAF spectrometer, the sensitivity of the instrument is excellent and the main source of measurement uncertainty that needs to be addressed by the analyser and the system design is the quenching effect; where other gases present in the sample, such as O2 and H2O, lower the fluorescence signal due to mercury atoms. In order to avoid these adverse effects, a dilution sampling approach is used and the dilution gas is synthetic nitrogen formed in a nitrogen generator inside the analyser cabinet. As the detection limit of the analyser is much lower than would be needed to monitor mercury in low µg/Nm3 ranges, dilution does not compromise the sensitivity of the instrument. On the other hand, dilution lowers the quenching effect by lowering the concentration of interfering gases by a factor of 50. Measuring mercury in a gas consisting of 98% nitrogen guarantees consistent measurement regardless of the fuel or emission abatement techniques used in the plant.

The CVAF spectrometer measures atomic mercury vapour (Hg0) and in order to measure total mercury including oxidized forms, a thermal catalytic converter is used to convert all forms of mercury such as Mercury Chloride into atomic mercury. The converter is close-coupled with the fluorescence cell to minimise the risk of recombination reactions where the atomic mercury converts back to oxidised forms between the converter and spectrometer.

The system has been field tested on various types of industrial plants (coal fired power plant, hazardous waste incinerator, sulphuric acid plant and a cement plant) to characterise the suitability and long-term stability of the sample probe and dilution system in various processes. Given the reactive nature of mercury, special care has been taken to ensure that mercury in the flue gas is not absorbed into dust accumulating in the sample probe filters. Mercury reacts readily with limestone dust, resulting in analyte loss and increased response time of the analyser. The Gasmet CMM solution includes a smaller filter element, which minimises the amount of dust deposition on the filter, and a two-stage blowback mechanism which first removes dust from the filter element and then in the second stage expels the dust from the probe tube back into the process.

Field test at Finnish Cement Plant

Figure 2

Figure 2

The CMM was installed on the emission stack of a rotary kiln cement plant with an Electrostatic Precipitator (ESP) for particulate emission control (see figure 2 above). The test period lasted 30 days. The fuels used during the test included coal, petroleum coke and recovered fuels. The flue gas composition at the measurement point is summarised in table 1. During the field trial, the raw mill was periodically stopped and the variation in mercury levels was monitored together with changes in other process parameters. Average mercury concentration when the raw mill was running was 6 to 8 µg/Nm3 and when the raw mill was stopped, the concentrations could increase to 20 – 40 µg/Nm3. The plant had an emission limit value of 50 µg/Nm3 for total mercury.

Figure 3

Figure 3

Figure 3 (above) shows a typical 24-hour period of emissions including raw mill on and raw mill off conditions. In addition to Hg0 concentration, the dust loading and raw mill state are shown because these are the main parameters expected to have an impact on the mercury analyser.

Results
The main goal of the test was to ensure the stability and repeatability of mercury measurement in demanding process conditions and to determine whether cement dust causes analyte loss and increased response time in the sample extraction probe.

The only process variable which clearly correlates with mercury concentration is the raw mill on/off state. When the raw mill is on, the variation in dust loading or other gas concentrations (O2, H2O, acid gases such as SO2 and HCl) does not correlate with variation observed in mercury concentration. When the raw mill is switched off, all gases including mercury undergo a change in concentration but this is clearly brought about by the raw mill state.

In order to estimate the repeatability of the Hg measurement at zero and span levels, the CMM analyser was configured to perform zero tests with synthetic nitrogen and span tests with Hg0 test gas generated by the mercury calibrator in the CMM system at 4 hour intervals. The normal test interval required by the analyser is 24 hours, but in the interest of creating more test data, the interval was shortened in this test. All test gases are injected into the probe upstream of particle filters so that the test gas has to pass through the potentially contaminated filters.

Figure 4

Figure 4

The results from six repeated span/zero test cycles are shown in figure 4 (above). The target level for the span check was 6.5 µg/Nm3 and the average span level was 6.60±0.036 µg/Nm3. The average result for the zero check was -0.006 ± 0.036964 µg/Nm3. If the dust accumulating in the sample extraction probe were to cause analyte loss during span tests, the later tests would show a decrease from the span check target value, but this was not observed. If the dust in the probe were to make the response time longer (memory effect), the later tests would show a slower response than the first tests. Again, there was no systematic change in the test results and the tests 1-6 exhibited very consistent results.

The span and zero checks also provided an opportunity to characterise the response time of the analyser when the span test at a known concentration is followed by a zero check with a zero concentration. The data from all six tests in figure 3 were combined together into one dataset in figure 4 by synchronising the moment when the span/zero check cycle was started. A Boltzmann sigmoidal curve (eqn 1) was fitted to the experimental data using GRG nonlinear fitting routine in the Microsoft Excel Solver package. The parameters of the response curve are summarised in table 2. The response time was evaluated as T90-10, the time interval between a reading representing 90% of the span check value and a reading representing 10% of the span check value.  The response time from this calculation was 10.15 minutes or just over two measurement cycles (measurement data is obtained as 5 minute rolling averages of the mercury concentration). The live data from the emissions shows peaks of comparable sharpness, but these were not subjected to the same analysis as the span/zero check data.

Summary
The requirements of a Continuous Mercury Monitoring system in a Cement plant are as follows:

  • capable of measuring a low baseline level with high sensitivity when the raw mill is on and the fuel feed contains low levels of metals
  • capable of measuring excursions to higher concentrations when the raw mill is off
  • low cross-interference from gases e.g. SO2
  • no analyte loss or other sampling issues in high dust loading
  • stable calibration and simplified calibration check routine with built-in calibration gas generator.

Since the main application areas for continuous Mercury monitoring systems have been in hazardous and municipal waste incineration, and coal fired power stations with conditions that are different to Cement plants; care must be taken to ensure that the monitoring system, and especially its sample extraction probe, is suitable for the process conditions. This study demonstrates that a CVAF spectrometer and dilution sampling approach can be successfully used in this application.


Wastewater treatment plant monitors Greenhouse Gas emissions!

15/04/2014

Globally, little attention is paid to gaseous emissions from wastewater treatment processes. This contrasts greatly with the regulatory monitoring that is applied to the quality of water emissions from such facilities. However, in Helsinki (FI), a large municipal wastewater treatment facility continuously monitors its emissions of greenhouse gases (GHGs) to help in the city’s efforts to combat climate change and also to help improve the wastewater treatment process.

Employing a multigas FTIR (Fourier Transform InfraRed) analyser from Gasmet, a Helsinki-based manufacturer of analytical instrumentation, the plant’s managers are able to measure the effects of process control on GHG emissions such as carbon dioxide, methane and nitrous oxide. This also provides an insight into the fate of nitrogenous compounds within the wastewater stream.

Background
The Viikinmäki wastewater treatment plant was built in 1994 to process wastewater from both domestic (85%) and industrial (15%) sources. However, the average temperature in Helsinki between December and February is around minus 4 DegC, with extremes below minus 20 and even minus 30 DegC, so the plant was built almost entirely underground to avoid the freezing temperatures. Underground construction is common practice in the Nordic countries, providing other advantages such as land availability above the plant and the provision of stable conditions for process control and odour management.

Viikinmäki Wastewater HSY (FI)

Viikinmäki Wastewater HSY (FI) (Photo courtesy of HSY)

The Viikinmäki plant is the largest wastewater treatment facility in Finland, handling approximately 270,000 m³ of wastewater per day, which amounts to about 100 million m³ per year. The wastewater is treated in compliance with the Finnish Wastewater Discharge Permit, which is stricter than the EU Water Framework Directive for parameters such as nitrogen removal, phosphate content, BOD, COD and suspended solids. Following treatment, the purified / treated wastewater is conveyed 8km out to sea and to a depth of over 20m. This might seem superfluous, but the 16 km long discharge pipe was built in the 1980s and was designed to ensure that discharged wastewater did not accumulate on the shallow and scattered shore and nature reserves along the coastline of Helsinki.

The treatment process is based on the activated sludge method and includes three phases: mechanical, biological and chemical treatment. Traditional nitrogen removal has been enhanced with a biological filter that utilises denitrification bacteria.

The organic matter contained in the sludge produced in the wastewater treatment process is exploited by digesting the sludge, and the biogas generated in the digestion process is collected for further use. Thanks to the energy produced from biogas, the treatment plant is self-sufficient in terms of heating and about 70 per cent self-sufficient in terms of electricity. However, the plant aims to be fully energy self-sufficient in the near future, and around 60,000 tonnes of dried waste sludge is sold each year for landscaping purposes.

Gas monitoring
As a result of the size of the plant (E-PRTR reporting) and the commitment of the Helsinki Region Environmental Services Authority (HSY) to the protection of the environment, it was necessary to monitor or to model gaseous emissions. At the beginning of the E-PRTR reporting requirements (2007) HSY modelled the annual gaseous emissions based on grab samples. However, monitoring was relatively simple to implement because the plant is enclosed underground and a gas exhaust system was already in place.

Viikinmaki Emissions Monitor

Viikinmaki Emissions Monitor (Photo courtesy of Gasmet Technologies)

Initially, a portable FTIR analyzer from Gasmet was hired for a short period to assess the plant’s emissions and for research purposes. However, as Mari Heinonen, Process Manager at Viikinmäki, reports: “The gas emissions data were very interesting but they were not representative of the annual emissions, and posed more questions than they answered.

“We therefore purchased a continuous emissions monitoring system (CEMS) from Gasmet, which was installed in late 2012 and we now have our first full year’s data for 2013.

“Very little data has been published on the GHG emissions of wastewater treatment and as far as we are aware, Viikinmäki is the only plant in the world conducting this type of monitoring, so our data is likely to be of major significance.”

The Gasmet CEMS employs an FTIR spectrometer to obtain infrared spectra from the waste gas stream by first collecting an ‘interferogram’ of the sample signal with an interferometer, which measures all infrared frequencies simultaneously to produce a spectrum from which qualitative and quantitative data are produced. For example, the CEMS at Viikinmäki continuously displays emissions data for CH4, N2O, CO2, NO, NO2, and NH3.

Over a number of years, Gasmet has established a library of FTIR reference spectra that now extends to simultaneous quantification of 50 gases or identification of unknowns from a collection of 5000+ gases. This means that it is possible to reanalyse produced spectra with the instrument’s PC based software (Calcmet) and thereby to identify unknown gases – a major advantage of FTIR.

Whilst FTIR is able to analyse an enormous number of gases, the technique is not suitable for noble gases, homonuclear diatomic gases (e.g., N2, Cl2, H2, F2, etc) or H2S (detection limit too high).

Gasmet FTIR technology was chosen for the Viikinmäki plant because of its ability to monitor multiple gases simultaneously. However Mari Heinonen says: “The system has performed very well, with very little maintenance required. Zero point calibration with nitrogen (background) just takes a few minutes each day and is fully automated. Water vapour calibration is conducted at least once per year, but under normal circumstances no other calibration is necessary.”

With the benefit of the monitoring data, Mari Heinonen has calculated the annual emissions for methane to be around 350 tonnes, and for nitrous oxide around 134 tonnes. This means that the emissions per cubic meter of wastewater equate to 3.5g of methane and 1.34g of nitrous oxide.

Looking forward, Mari believes that it will be possible to use the gas monitoring data to improve process control: “Traditional monitoring/control systems focus on concentrations of oxygen, nitrate and ammonia in the water, but if we detect high levels of N2O gas for example, this may indicate a problem in the process that we can use as a feedback control.

“The monitoring data for gaseous nitrogen compounds (N2O, NH3, NOx) complements water analysis and provides a more complete picture of the nitrogen cycle in the treatment process.

“Clearly, further research will be required, but this work may indicate a need to consider the fate of nitrogenous compounds beyond just those in the wastewater; the removal of nitrogen from wastewater is a key objective, but if this results in high N2O emissions the process may need to be managed in a different way.”


Germany lowers biogas formaldehyde emissions

23/12/2013

Power generation from Germany’s enormous biogas industry produces emissions to air that are regulated by the Technical Instructions on Air Quality Control (TA Luft). As part of the approval process, the emissions from each plant have to be tested every three years. Formaldehyde is one of the pollutants of greatest concern because of its carcinogenicity and the TA Luft emission limit is 60 mg/m³. However, the German Government has also created a financial incentive scheme to encourage process managers to lower their formaldehyde emissions to below 40 mg/m³. To be eligible for the EEG (Erneuerbare Energien Gesetz) scheme, plants must be tested every year.

VDI_TestSiteFormaldehyde (HCHO) can be difficult to measure in hot, wet emissions, not least because it would dissolve in condensate if the sample gas is allowed to cool. Test engineers in Germany have therefore deployed portable (DX 4000 and CX4000 from Gasmet) FTIR analyzers to measure formaldehyde, and a number of systems are currently in use across Germany.

Background
The biogas industry in Germany has grown enormously in recent years; in 1992 there were 139 biogas plants in the country, but by the end of 2013 there will be almost 8,000 with an electrical capacity of about 3,400 MW – sufficient for the energy needs of around 6.5 million households. Initially, biogas plants were built to handle the by-products of human and animal food production as well as agricultural waste, but with government incentives to generate renewable energy, farmers are now growing crops such as maize specifically for energy production.

Biogas is produced by anaerobic digestion with anaerobic bacteria or fermentation of biodegradable materials. The main constituent gases are methane and carbon dioxide, with small amounts of hydrogen sulphide and water. The products of biogas combustion are mostly carbon dioxide and water, but the combustion of biogas also produces formaldehyde.

Biogas-fuelled combined heat and power (CHP) plants are becoming a very popular source of renewable energy in many countries because they provide a reliable, consistent source of energy in comparison with wind and solar power. In addition to the renewable energy that these plants produce; the fermentation residue is a valuable product that can be used as a fertiliser and soil conditioner for agricultural, horticultural and landscaping purposes.

Exhaust gas tests
The exhaust emissions of each biogas plant are tested every three years for substances hazardous to air quality, such as particulates, carbon monoxide, nitrogen oxides, sulphur dioxide and formaldehyde. Most of these parameters can be measured on-site with portable equipment. However, in the early years and still to this day, the complexity of formaldehyde analysis has necessitated sampling and laboratory analysis – a time-consuming and costly activity.

FTIR_DX4000

FTIR_DX4000

In 2007 Wolfgang Schreier from the environmental analysis company RUK GmbH (now part of the SGS Group) started working on the use of portable FTIR gas analysers for formaldehyde analysis. The FTIR analysers are manufactured by Gasmet (Finland) and supplied in Germany by Ansyco GmbH, a Gasmet group company.

FTIR analysers are able to qualitatively and quantitatively analyse an almost endless number of gas species. However, Wolfgang Schreier says: “The Gasmet units are primarily employed for the measurement of formaldehyde, and whilst they are able to measure other parameters of interest such as CO, NOx and Methane, they are not yet certified for doing so in the emissions of biogas plants, unless an internal validation has been undertaken.

“The DX4000 proved to be the ideal instrument for this application because it samples at high temperatures (above 180 Deg C) so formaldehyde cannot dissolve in condensate, and the instrument provides sensitive, accurate, reliable real-time formaldehyde measurements – no other portable analyser is able to achieve this.

“Importantly, the DX4000 is also robust and weighing just 14kg, it is easy to transport from site to site. In addition to a heated sample line, the only other accessory is a laptop running Gasmet’s Calcmet™ software.”

In contrast with the portable FTIR, it is typical for the results of laboratory gas analysis to become available around 2 weeks after sampling. This highlights a further benefit of the direct-reading instrument; real-time results enable plant managers to adjust their process in order to improve efficiency and minimise the emissions of formaldehyde and other gases.

Ansyco’s Gerhard Zwick says: “We hope that the other measurements that are possible with the Gasmet FTIR will also soon be accepted. A new VDI method (VDI 3862-8) for the measurement of formaldehyde by FTIR is being established and this is likely to be published at the beginning of 2014.

“The preparation of this standard involved rigorous field tests with 5 Gasmet FTIR analysers at a live biogas plant. During testing, samples were taken for analysis according to the existing standard laboratory methods and the results showed that portable FTIR produced even better results than lab analysis.”

Formaldehyde reduction incentive
The bonus is paid to the operators of biogas plants which are subject to approval by the Federal Immission Control Act if certain conditions are met. Measurements to demonstrate the effectiveness of emission reduction have be taken each year by an organisation which is approved according to § 26 of the Act.

While the emission limit for formaldehyde is 60 mg/m3, according to the EEG legislative, the plant operator receives a bonus of 1 cent per kW when formaldehyde emission levels are below 40 mg/m3, with simultaneous fulfilment of the emission limits for nitrogen monoxide and nitrogen dioxide (combined), and for carbon monoxide.

With the benefit of real-time readings from the FTIR, process operators are able to employ process control measures to alter formaldehyde emissions. However, this may also affect the efficiency of the combustion process or the concentrations of other limited gases. In addition, it is now commonplace for modern plants to use a catalyst for formaldehyde emission reduction.

Summarising Gerhard Zwick says: “The standard formaldehyde emissions monitoring package consists of a Gasmet DX4000 analyser and a heated sampling system, so no adaptations were necessary for the measurement of biogas emissions.

“We have now supplied instruments to most of the key testing organisations as well as motor and system manufacturers in Germany. Happily, the feedback has been extremely positive because, as a portable analyser, the Gasmet FTIR systems are able to test more plants, more quickly, and this lowers costs.”


Moo gas! Ruminants with less impact on the environment

21/06/2013

Research highlights cattle emissions reduction opportunity

Author: Antti Heikkilä, Gasmet Europe Oy

Researchers in Denmark have measured the quantities of greenhouse gases in the breath of dairy cows and demonstrated a heritable variability between individual animals.  “This means that we have an opportunity to select for breeding those individuals which will produce offspring that generate less methane,” says Dr Jan Lassen who led the research project on individual methane measurements from dairy cows at Aarhus University.

Background
beithigOver the last 60 years, dairy cattle have been selectively bred to maximise milk production and as a result, cows have become extremely efficient at converting food such as grass, silage, hay and concentrates into agricultural products such as milk and meat. At the same time, feed quality, ration formulation and herd management have all contributed to the overall increase on productivity. However, one of the by-products of rumination, the process by which animals such as sheep and cattle digest food, is methane – a powerful greenhouse gas (GHG).

Retrospective calculations made by (Chase 2006) indicate there has been a 40% reduction in methane emissions per litre of milk produced in the USA from 1944 to 2007. Nevertheless, over the course of a year, the methane from one cow’s belches is currently equivalent to the carbon dioxide emission from a small car. Globally, it has been estimated that livestock account for 15% of total GHG emissions (Steinfeld et al., 2006), so there is a great deal of interest in finding ways to reduce this value.

The global warming potential of methane is about 25 times that of carbon dioxide (Forster et al., 2007), so a small reduction in methane production could have significantly beneficial effects.

Recently, researchers in a number of countries have shown that it is possible to reduce methane emission from cows by altering their diet, but this is only likely to have a beneficial effect on GHG emissions if the necessary feeds are available to farmers at a cost that does not increase the overall cost of the diet, and if these feeds do not have a negative effect on animal production. However, if those individuals that generate lower levels of methane can be identified, it would be possible to build this into breeding programmes.

Gas sampling during milking

Gas sampling during milking

Gas sampling
Methane is a by-product of fermentation in the rumen and is expelled by belching or eructation. Around 80% of ruminant methane emissions emerge from the mouth of the animal, with only 20% emitted from the rear (Verge et la., 2007), so the Danish workers have focused on the breath of cows in their research.  Naturally, it can be difficult to capture all of a cow’s breath under natural conditions, so the Danish workers constructed a sampling system that collected the breath of cows as they stood in an automatic milking machine – an activity which took place between 2 and 12 times per day during the research programme.

Gas analysis
The two main GHGs of interest were methane and carbon dioxide, and these were measured simultaneously with a Gasmet FTIR (Fourier Transform InfraRed) analyser. Initially, a Gasmet DX4030 portable FTIR analyzer was borrowed from the University of Copenhagen for this work, but subsequently a similar analyzer, a Gasmet DX4000 was purchased and built into a customised air-conditioned chamber that protected the analyzer from dust and dirt.

FTIR
An FTIR spectrometer obtains infrared spectra by first collecting an ‘interferogram’ of a sample signal with an interferometer, which measures all infrared frequencies simultaneously to produce a spectrum. High levels of accuracy and low levels of maintenance are achieved as a result of continuous calibration with a He-Ne laser, which provides a stable wavenumber scale. In addition, high spectral signal to noise ratio and high wavenumber precision are characteristic of the FTIR method.

FTIR Analyser in bespoke tray

FTIR Analyser in bespoke tray

While the Gasmet FTIR is able to measure methane and carbon dioxide continuously, it also produces spectra for the sampled gases from which it is possible to determine the concentrations of hundreds of other gases. This was an important consideration in the choice of FTIR. “Simpler, lower cost analyzers are available for measuring methane and carbon dioxide,” says Jan Lassen, “but we wanted to build a comprehensive picture of cattle breath analysis, over as many animals as possible and for as many chemical species as possible.

“The Gasmet FTIR is supplied with ‘Calcmet’ software which enables us to store the spectra and this is critically important, because it means that our research can be used by us or other workers in the future.

“Calcmet contains a library of reference spectra that extends to simultaneous quantification of 50 gases or identification of unknowns from a collection of 5000+ gases. This means that it is possible to retrospectively analyse produced spectra for almost any chemical species.

“Initially, we were most interested in methane and carbon dioxide, but in the future we plan to study the levels of gases such as acetone, ammonia, ethanol and nitrous oxide. These gases are very likely to be indicators of metabolic efficiency, so the FTIR spectra could open new opportunities for improving the efficiency of animal production.”

Results and conclusions
Both concentrate feed intake and total mixed ration intake were positively related to methane production, whereas milk production level was not correlated with methane production. Following research involving over one thousand cows, methane production was found to vary between individuals by around 20% and this was shown to be a heritable trait. In other research, a heritable variability of 13% was found in sheep (Robinson et al., 2010).

Similar research at the University of Nottingham, UK, also concluded that variability between individuals might offer opportunities for genetic selection (Garnsworthy et al., 2012).

Much of the success that has been achieved in the improvement of dairy cattle performance has been through the selection of bulls with offspring that display desirable traits – high milk yield or beef production efficiency for example. This research has shown that it is possible to measure the methane production rates of cattle and thereby to infer a ‘methane score’ for individual bulls, so that this could become a selection criterion for farmers when choosing sires for dairy herds.

By selecting sires with a good methane score, dairy farmers could make a significant contribution to the fight against climate change. However, it may be difficult to encourage them to make such choices unless there is a significant commercial reason for doing so. On this point, Jan Lassen says “The eructation of methane represents a loss of energy and therefore a lowering of production efficiency, so it makes commercial sense for farmers to select individuals with a better methane score, not just because it helps fight climate change, but also because it probably improves the efficiency of ruminant digestion in offspring.”

Looking forward
Dr Lassen hopes that international projects that aim to combine the data obtained from research such as his with others in other countries can be initiated soon. For example, he is aware of several researchers conducting similar work with Gasmet FTIR analyzers in other countries, and gas analysis spectra from these projects will be combined to improve the understanding of methane production heritability. However, these spectra also offer an excellent opportunity to analyse different chemical species in order to further investigate ruminant productivity.

FTIR gas analysis is now being employed for the measurement of GHGs in a wide variety of applications including industrial emissions, automotive emissions, and gas flux measurements in Arctic soils. This provides two important benefits for future research; firstly, Gasmet staff are now highly experienced in configuring systems to measure GHGs and secondly, an enormous library of stored spectra has been created, which will help future researchers to analyse both new and old measurements.

As more data is collected from larger numbers of cattle, it will become possible to establish a methane score for specific bulls and Dr Lassen is optimistic that this will become a selection criterion in the future.

References 

Chase, L.E. 2006. How much methane do cows emit? Proc. Cornell Nutr. Conf., Syracuse, NY. Pp: 219-226.

Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D. W. Fahey, J. Haywood, J. Lean, D. C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Schulz, and R. Van Dorland. 2007. Changes in atmospheric constituents and in radiative forcing. Pages 129–234 in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor and H. L. Miller, ed. Cambridge University Press, Cambridge, UK and New York, NY.

Garnsworthy P.C., J. Craigon, J. H. Hernandez-Medrano, and N. Saunders. 2012. Variation among individual dairy cows in methane measurements made on farm during milking.

Robinson, D. L., J. P. Goopy, R. S. Hegarty, and P. E. Vercoe. 2010. Repeatability, animal and sire variation in 1-hr methane emissions and relationship with rumen volatile fatty acid concentrations. Abstract no 712 in: Proc. 9th World Congress in Genetics Applied to Livestock. Book of Abstracts.

Steinfeld, H., P. Gerber, T. Wassenaar, V. Castel, M. Rosales,and C. de Haan.  2006.  Livestock’s  Long  Shadow:  Environmental  Issues and  Options. Food and Agriculture  Organization  of  the  United Nations (FAO), Rome, Italy.

Vergé, X. P. C., J. A. Dyer, R. L. Desjardins, and D. Worth. 2007.

Greenhouse gas emissions from the Canadian dairy industry in 2001. Agric. Syst. 94:683–693.