Gas sensing

Vaisala probes facilitate rollout of environmentally friendly refrigeration

Supermarkets all over Australia and New Zealand are benefiting from advanced carbon dioxide monitors as new natural refrigeration systems are installed in the fight against climate change.

The Woolworths Group employs over 205,000 staff and serves 900 million customers each year. As a large and diverse organisation, Woolworths knows that its approach to sustainability has an impact on national economies, communities and environments, and this is reflected in the Group’s Corporate Responsibility Strategy 2020.

The strategy is built around twenty key targets which cover Woolworths’ engagement with customers, communities, supply chain and team members, as well as its responsibility to minimise the environmental impact of its operations. One of the twenty commitments within the strategy is to innovate with natural refrigerants and reduce refrigerant leakage in its stores by 15 per cent (of carbon dioxide equivalent) below 2015 levels.

Carbon dioxide (CO2) is commonly regarded as the ideal natural refrigerant. It is a non-toxic, non-flammable, odourless, colourless gas, however, high concentrations can cause unconsciousness and even death, so accurate, reliable monitoring is necessary for safety reasons and for the rapid detection of potential leaks. Woolworths, and its cold chain partner Emerson, therefore needed an accurate, reliable CO2 monitor that could fulfil this vital role as the Group expands the use of natural refrigerants in its stores.

Over the last 8 years, Vaisala carbon dioxide probes have been employed widely across Woolworths Group stores, delivering a range of benefits and helping the group to achieve its strategic goals.

Global move to natural refrigerants

Synthetic refrigerant gases have been utilised in a wide variety of industries for many decades. However, Chlorofluorocarbons (CFCs) caused damage to the ozone layer and were phased out following the Montreal Protocol in 1987. Production of Hydrochlorofluorocarbons (HCFCs) then increased globally, because they are less harmful to stratospheric ozone. However, HCFCs are very powerful greenhouse gases so Hydrofluorocarbons (HFCs) became more popular. Nevertheless, most HCFCs and HFCs have a global warming potential (GWP) that is thousands of times higher than that of carbon dioxide, so many countries have been lowering the use of HFCs, and the Kigali Amendment (2018) to the Montreal Protocol, will bring about a global phasedown of HFCs. Consequently, there is a strong push for the adoption of natural refrigerants such as carbon dioxide.

In Australia and New Zealand, Woolworths Group is leading the way in the move to refrigerants that have a dramatically lower GWP. Luke Breeuwer, Senior Commissioner at Woolworths, says: “I believe that ultimately all supermarket refrigeration, in store and back of house, will move to transcritical CO2, unless a better method emerges.

“CO2 refrigeration technology has improved markedly in recent years, which is enabling us to roll it out in most regions, except for parts of Queensland where humidity levels currently dictate the deployment of hybrid CO2 systems.”

The move to transcritical CO2 refrigeration systems involves a significant capital outlay, which may limit the speed of implementation at other supermarkets. At Woolworths Luke says: “There is pressure from our finance department to push ahead with the new systems; not just to deliver environmental benefits, but also to ensure that at some point in the future, we are not left with refrigeration assets that cannot be maintained. The capital costs of the initiative are being offset by also utilising this technology for in-store heating.”

Monitoring Carbon Dioxide

To protect the health and safety of customers, staff and contractors, around six CO2 sensors would be necessary in a traditional store. However, those with transcritical CO2 refrigeration would typically require twenty four sensors or more.

Many of the Woolworths stores’ refrigeration and HVAC control systems are supplied by Emerson. Looking back, Shannon Lovett, Senior Business Manager Cold Chain ANZ for Emerson, says: “Around 8 years ago we evaluated a locally sourced CO2 sensor, but it suffered from quality issues and failures, so we equipped one store with the Vaisala sensors as a ‘proof of concept’.

“Happily, the Vaisala probes performed extremely well, and have been rolled out in the Woolworths Group stores in Australia and New Zealand. We have also utilised Vaisala humidity and temperature sensors in a variety of similar applications. In comparison with some other CO2 sensors, the Vaisala monitors were more expensive, but they were very popular with our contractors and we found that Vaisala’s product reliability lowered the cost of ownership.”

Luke Breeuwer agrees with Shannon on the longer term benefits of investing in higher quality instruments, adding: “The MODBUS communications capability of the Vaisala Indigo200 Transmitter with the GMP252 probe is also a major advantage for us; it means that the amount of wiring required is substantially reduced, which lowers both complexity and costs.”

Commenting on the reliability of the Vaisala probes, Luke says: “We have large numbers of these sensors in operation but there have been no breakdowns or urgent call-outs, so the ongoing costs have been negligible. We are required to check sensor calibration every two years, but they are so stable that this check always shows the sensors to be within specification, which is great.”

Luke does recall one occasion when the accuracy of a Vaisala CO2 sensor was called into question. An installed probe was providing readings that were abnormally low, so a site visit was necessary. However, such was their faith in the sensors that an alternative explanation was sought, and after a period of speculation a Google search solved the mystery by revealing the propensity of (nearby) curing concrete to absorb CO2 through a process known as carbonation.

Advanced sensor technology

The Vaisala CARBOCAP Carbon Dioxide Probe GMP252 is an intelligent carbon dioxide sensor designed for harsh and humid environments where stable and accurate CO2 measurements are required. Importantly, the probe features second generation CARBOCAP technology. In addition to measuring CO2, an electrically tunable micromechanical filter enables a reference measurement at a wavelength where no absorption occurs. The reference measurement compensates for any potential changes in the light source intensity, as well as for contamination in the optical path, which means that the sensor is extremely stable over time. The probe also automatically compensates for temperature, pressure, oxygen and humidity, and with an operating temperature range from -40 to +60 °C, the sensor is able to measure CO2 accurately from 0 to 10,000 ppm, and up to 30,000 ppm with reduced accuracy.

Benefits of the Vaisala technology

From Woolworths’ perspective Luke says: “The main advantages are reliability, low maintenance and MODBUS communications. However, flexibility is important because we also utilise the Vaisala probes in-store to ensure that CO2 levels do not rise excessively. We achieve this by using monitoring data to automatically control and optimise fresh air intake.”

Emerson integrates the probes within its building management systems and Shannon highlights the facility to utilise a dual relay output for local alarms as a particularly useful feature. “Reliability is of course the main advantage for us,” he adds. “But the negligible maintenance requirement, the two year calibration check and MODBUS comms provide us with competitive advantages.”

Looking forward

By identifying the role of natural refrigerants in its Corporate Responsibility Strategy, Woolworths has made a very clear statement of intent. Two years ago, there were no transcritical CO2 stores in the group, but seven stores have now been converted and up to a dozen largely metropolitan stores will be converted in the coming year.

Summarising Luke says: “By utilising CO2 in our refrigeration systems we are helping to lower greenhouse gas emissions whilst also lowering operational costs. However, reliable CO2 monitoring plays a vitally important role; protecting staff and the public, while helping to identify and reduce leakage – a win win situation!”

Bats inspire detectors to help prevent oil and gas pipe leaks

Engineers have developed a new scanning technique inspired by the natural world that can detect corroding metals in oil and gas pipelines.

By mimicking how bats use differing wavelengths of ultrasound to detect objects, hunt, and avoid predators, engineers have developed a new system that combines two separate types of radiation, fast neutrons and gamma rays, to detect corrosion – a major cause of pipeline leaks.

With thousands of kilometres of pipelines used to transport oil and gas over huge distances globally, leaks are a major issue costing millions annually and have the potential to cause accidents and injuries as well as significant environmental damage.

Typically, corrosion in oil pipelines is measured with ultrasonic or electromagnetic techniques. However, these are not practical for underground pipelines, or for pipelines covered with insulating layers of concrete or plastic.

The new system, developed by Engineers from Lancaster University, the National Physical Laboratory, and a technology company, Hybrid Instruments Ltd, exploits the reflected signals, known as ‘backscatter’, of a combination of isolated fast-neutron and gamma radiation.

Neutrons and gamma rays have useful complementary characteristics. Neutrons interact mainly with low-density materials like plastics. In addition, fast neutrons have a high penetrating power, so they are suitable for probing thick materials. Gamma rays interact mainly with metals and not always are able to penetrate very thick materials of high density.

The two radiation types produce a different electronic signal. This means researchers can retain data on both types of radiation simultaneously using a novel detecting device called a ‘Mixed Field Analyser’, previously developed by Lancaster University and Hybrid Instruments Ltd.

The system produces a pencil-like beam of probing radiation, of neutrons and gamma, which is directed at the steel section being inspected.

The team tested the two imaging techniques in real time in a laboratory on samples of carbon-steel of different thicknesses.

The researchers were able to see differences in steel thickness. The sensors also worked when an insulating layer was replicated, with concrete or plastic, indicating the likelihood that defects in steels, as well as corrosion and rust, would produce variations in the backscatter.

These results indicate that if used on real pipelines then potential issues could be more easily detected and resolved before oil and gas is able to escape.

“The combined beams of neutrons and gamma rays in parallel bouncing back to an array of detectors yield a comprehensive and fast representation of the inner structure of steel,” said Mauro Licata, PhD researcher on the project from Lancaster University.

“This system works a bit like the chirps made by bats. These chirps are a superposition of different ultrasound wavelengths, which bounce back to the bats’ ears. As well as highlighting the benefits of combining multiple reflection sensing techniques to detect for problems such as corrosion, our work further illustrates the significant potential that can be had from taking inspiration from, and mimicking, systems that have evolved in the natural world.”

“Isolating neutrons and gamma rays backscattered from a steel surface in real time, in a way analogous to the way bats’ brains isolate backscatter ultrasound and thus avoid confusion with their own chirps, could help us isolate flaws in pipe walls more quickly and effectively,” said Professor Malcolm Joyce of Lancaster University and Hybrid Instruments Ltd. “This is a great example of NPL’s world-leading neutron facilities being used for innovative science with a positive impact,” said Neil Roberts of the National Physical Laboratory.

The intention is that the detector system would be further developed and used to detect faults by pointing it at sections of pipeline from the outside. However, the investigators say more research is needed in the field of neutron detectors to make the system faster.

The researchers suggest the technology could also be used in other applications, such as inspecting the integrity of structures such as bridges.

The research has been outlined in the paper ‘Depicting corrosion-born defects in pipelines with combined neutron/γ ray backscatter: a biometric approach’, which has been published by the journal Scientific Reports.

Research zeroing in on electronic nose for monitoring air quality

Research at Oregon State University has pushed science closer to developing an electronic nose for monitoring air quality, detecting safety threats and diagnosing diseases by measuring gases in a patient’s breath.

Depiction of a gas sensor array composed of microscale balances coated with thin films of nanoporous materials called metal-organic frameworks. Credit: Arni Sturluson, Melanie Huynh, OSU College of Engineering

Recently published research led by Cory Simon, assistant professor of chemical engineering in the OSU College of Engineering, in collaboration with chemical engineering professor Chih-Hung Chang focused on materials known as metal-organic frameworks, or MOFs.

The research took aim at a critical yet understudied hurdle in using MOFs as gas sensors: Out of the billions of possible MOFs, how do you determine the right ones for building the optimal electronic nose?

MOFs have nanosized pores and selectively adsorb gases, similar to a sponge. They are ideal for use in sensor arrays because of their tunability, enabling engineers to use a diverse set of materials that allows an array of MOF-based sensors to deliver detailed information.

Depending on which components make up a gas, different amounts of the gas will adsorb in each MOF. That means the composition of a gas can be inferred by measuring the adsorbed gas in the array of MOFs using micro-scale balances.

The challenge is that all MOFs adsorb all gases – not to the same extent, but nevertheless the absence of perfect selectivity prevents an engineer from simply saying, “let’s just dedicate this MOF to carbon dioxide, that one to sulfur dioxide, and another one to nitrogen dioxide.”

“Curating MOFs for gas sensor arrays is not that simple because each MOF in the array will appreciably adsorb all three of those gases,” Simon said.

Human noses navigate this same problem by relying on about 400 different types of olfactory receptors. Much like the MOFs, each olfactory receptor is activated by many different odours, and each odour activates many different receptors; the brain parses the response pattern, allowing people to distinguish a multitude of different odours.

Visualisation of the crystal structure of an archetype metal-organic framework, IRMOF-1. Gas molecules readily adsorb into the nano-pores of IRMOF-1. Image provided by Cory Simon, OSU College of Engineering.

“In our research, we created a mathematical framework that allows us, based on the adsorption properties of MOFs, to decide which combination of MOFs is optimal for a gas sensor array,” Simon said. “There will inevitably be some small errors in the measurements of the mass of adsorbed gas, and those errors will corrupt the prediction of the gas composition based on the sensor array response. Our model assesses how well a given combination of MOFs will prevent those small errors from corrupting the estimate of the gas composition.”

Though the research was primarily mathematical modeling, the scientists used experimental adsorption data in real MOFs as input, Simon said, adding that Chang is an experimentalist “who we are working with to make a real-life electronic nose to detect air pollutants.”

“We are currently seeking external funding together to bring this novel concept into physical realisation,” Simon said. “Because of this paper, we now have a rational method to computationally design the sensory array, which encompasses simulating gas adsorption in the MOFs with molecular models and simulations to predict their adsorption properties, then using our mathematical method to screen the various combinations of MOFs for the most accurate sensor array.”

Meaning that instead of an experimental trial-and-error approach to decide which MOFs to use in a sensor array, engineers can use computational power to curate the best collection of MOFs for an electronic nose.

Another exciting application of such a nose could be diagnosing disease. The volatile organic compounds humans emit, such as through our breath, are filled with biomarkers for multiple diseases, and studies have shown that dogs — which have twice the number of different olfactory receptors as humans — can detect diseases with their nose.

Marvelous though they are, however, dogs’ noses aren’t as practical for widespread diagnostic use as a carefully crafted and manufactured sensor array would be.

A wearable gas sensor for health and environmental monitoring

A highly sensitive, wearable gas sensor for environmental and human health monitoring may soon become commercially available, according to researchers at Penn State and Northeastern University.

A wearable gas sensor can monitor environmental and medical conditions. Credit: Cheng Lab/Penn State

The sensor device is an improvement on existing wearable sensors because it uses a self-heating mechanism that enhances sensitivity. It allows for quick recovery and reuse of the device. Other devices of this type require an external heater. In addition, other wearable sensors require an expensive and time-consuming lithography process under cleanroom conditions.

Hand and arm showing sensor applied to inner write with moble phone sized read beside it.

“People like to use nanomaterials for sensing because their large surface-to-volume ratio makes them highly sensitive,” said Huanyu Cheng, assistant professor of engineering science and mechanics and materials science and engineering, Penn State. “The problem is the nanomaterial is not something we can easily hook up to with wires to receive the signal, necessitating the need for something called interdigitated electrodes, which are like the digits on your hand.”

Cheng and his team use a laser to pattern a highly porous single line of nanomaterial similar to graphene for sensors that detect gas, biomolecules, and in the future, chemicals. In the non-sensing portion of the device platform, the team creates a series of serpentine lines that they coat with silver. When they apply an electrical current to the silver, the gas sensing region will locally heat up due to significantly larger electrical resistance, eliminating the need for a separate heater. The serpentine lines allow the device to stretch, like springs, to adjust to the flexing of the body for wearable sensors.

The nanomaterials used in this work are reduced graphene oxide and molybdenum disulfide, or a combination of the two; or a metal oxide composite consisting of a core of zinc oxide and a shell of copper oxide, representing the two classes of widely used gas sensor materials — low-dimensional and metal oxide nanomaterials.

“Using a CO2 laser, often found in machine shops, we can easily make multiple sensors on our platform,” Cheng said. “We plan to have tens to a hundred sensors, each selective to a different molecule, like an electronic nose, to decode multiple components in a complex mixture.”

The U.S. Defense Threat Reduction Agency is interested in this wearable sensor to detect chemical and biological agents that could damage the nerves or lungs, according to the researchers. A medical device company is also working with the team to scale up production for patient health monitoring, including gaseous biomarker detection from the human body and environmental detection of pollutants that can affect the lungs.

Ning Yi, a doctoral student in Chen’s lab and co-lead author of the paper posted online in the Journal of Materials Chemistry A, said, “In this paper, we showed that we could detect nitrogen dioxide, which is produced by vehicle emissions. We can also detect sulfur dioxide, which, together with nitrogen dioxide, causes acid rain. All these gases can be an issue in industrial safety.”

The researchers said their next step is to create high-density arrays and try some ideas to improve the signal and make the sensors more selective. This may involve using machine learning to identify the distinct signals of individual molecules on the platform.

IGE Consulting uses Ion Science TigerLT instrument for risk assessments of on-site contamination

Geo-environmental consultancy, IGE Consulting, is using a TigerLT handheld photoionisation detector (PID) from Ion Science to provide comprehensive risk assessments of on-site contamination. Supplied by UK-based distributor, Shawcity, the instrument was chosen for its flexible lamp design options that target different ranges and types of gases, and is monitoring potentially dangerous volatile organic compounds (VOCs) in soils which may cause harm to human health or compromise safety.

Manchester-based IGE Consulting undertakes desk studies and intrusive site investigation works on sites to be developed into residential or commercial developments. The company operates across the UK and provides a tailored service to meet client requirements such as pre-acquisition / planning development, abnormal costing evaluations, site investigation works and construction efficiency savings.

Molly Brown, Geo-environmental Engineer at IGE Consulting comments: “We previously hired the Ion Science TigerLT for monitoring VOCs in soils so have used it numerous times with great success. To save costs in the long term, it made sense to purchase one of the instruments. It also adds value to our site investigations and reports as we are able to provide a more comprehensive risk assessment.”

Molly continues: “One of the most appealing features of the TigerLT for us is the different options for lamps which allow various VOC gases to be detected. For example, we can choose lamps that give us a wide range or target specific ranges if we need to look for a particular type of VOC gas.”

Ion Science’s TigerLT, which offers worldwide Intrinsic Safety (IS) certification for use in potentially explosive atmospheres, is a streamlined, low-cost version of Ion Science’s well proven Tiger PID model.

Like all Ion Science PID instruments, the TigerLT incorporates the company’s market-leading PID technology with advanced patented fence electrode system. This three-electrode format ensures increased resistance to humidity and contamination for ultimate reliability and accuracy in the field.

With a detection range of 0.1 – 5,000 ppm utilising a standard two-point calibration protocol, Ion Science’s robust TigerLT also offers an unrivalled industry response time of just two seconds and equally quick clear down.

Both simple to operate and service, the TigerLT offers easy access to the lamp and sensor with batteries that can be safely replaced in hazardous environments. The intrinsically safe instrument also meets ATEX, IECEx, North American and Canadian standards.

Molly continues: “The TigerLT instrument is working well and enables us to provide a more comprehensive risk assessment of on-site contamination and the associated human health risk.

“In fact, the TigerLT PID instrument has already reduced costs for one of our clients by locating a VOC hotspot and proving blanks elsewhere on site meaning they did not have to install a VOC barrier on proposed plots. This client now only has to install VOC barriers on four out of 54 locations.”

The key advantage of TigerLT over other similar, low-cost handheld PID instruments is its market-leading accuracy and run time due to its anti-contamination and humidity-resistant design. Another attribute is its global Intrinsic Safety certification. Although the accreditation process can differ from country to country, the TigerLT can be used in explosive hazardous areas such as within petrochemical plants that are located anywhere in the world.

The TigerLT six pin MiniPID detector cell with anti-contamination design dramatically extends run time in the field. Low cost filters and lamps can be easily changed in minutes, minimising downtime.

It features long life rechargeable Li-ion batteries which give up to 24 hours usage. Fast battery charging allows the instrument to be fully charged in 6.5 hours, while eight hours of use can be achieved from 1.5 hours of charging time.

TigerLT features a protective, removable boot for harsh environments while a large, clear back-lit display allows for easy viewing in any light condition. It is IP65 rated against water ingress. An integrated torch is designed for directing the instrument’s probe into dimly lit areas. Other features include a loud 95 dB audible alarm and multiple language support.

Ready to use, straight out of the box, the TigerLT does not require complicated set-up procedures via a PC to perform basic functions.

“The Tiger LT is performing well and as expected from our previous experience. The service provided by Shawcity was good with fast delivery. Overall, we are very happy and would recommend the instrument to other environmental and geotechnical consultancies,” Molly concludes.

Gas Sensing Solutions Appoints Julian Hayes as new CEO

Gas Sensing Solutions (GSS) has announced the appointment of Julian Hayes as chief executive officer, taking over from Calum MacGregor who is retiring after 14 years with the company.

Hayes comes with wealth of knowledge and expertise in helping develop high technology businesses, having previously worked at a number of UK and global semiconductor, laser optics and components businesses.  GSS is a global leader in the development of high-performance carbon dioxide sensors for demanding markets such as aerospace, healthcare and environmental monitoring.

The last 12 months have been particularly strong for Gas Sensing Solutions, having launched 3 new ultra-low products to market, which have been well received by tier 1 customers.  The company has also taken the strategic decision to offer customised solutions, allowing customers to optimise the use of its CO2 sensors for the target application.

Martin Reynard, Chairman of GSS said, “Julian brings significant expertise in helping take high technology businesses to a global audience.  His experience will be invaluable in maintaining the growth GSS has achieved recently.  I would also like to take this opportunity to thank Calum for his incalculable contribution to the development of GSS and creating the platform for growth.”

Julian Hayes, CEO of GSS said, “It is an exciting time to be joining Gas Sensing Solutions. The past few years has seen GSS establish itself as the company of choice for high performance CO2 sensors across the globe.  I look forward to working with the great team at GSS and helping drive revenue growth with our partners and customers.”

Perfecting heat treatment and endothermic processing

For iron and steel, one of the most common approaches for hardening these relatively soft materials is to perform heat treatment under endothermic atmospheres. There are many methods for heat-treating metal alloys, some of which include case-hardening or surface hardening and annealing, but the general purpose of the treatment is to help improve the durability or hardness of the material.

To achieve these improvements in the hardness properties for alloys, heat treatment involves several stages. These are generally divided into annealing, quenching, and tempering. Annealing involves first heating the metal to a given temperature for a certain length of time and afterward using a controlled rate of cooling. Quenching involves rapid temperature reduction of the material to make the alloy very hard. Often such hardness can lead to brittle materials, so tempering can be used to restore some of the elasticity.

Environmental Factors

Careful control of conditions throughout all of the stages of heat treatment is required for maximum control of the final material properties, including that of the surrounding environment. Using endothermic gases, such as CO, H2, and N2, is part of maintaining fine control of the heat treatment processes.

The purpose of the endothermic environment is to ensure the right environmental conditions for the hardening process. This helps ensure that the correct chemical reactions occur to preserve the desired physical properties of the metal. Such atmospheres can also be used as carrier gases for other species in processes such as carburizing or carbonitriding. Part of the hardening process involves the decomposition of the carbon-rich gases causes migration onto the surface layers of the metal.

As well as ensuring the correct concentrations of endothermic gases in heat treatment for their thermal properties, CO2 concentrations need to be controlled as excess CO2 levels can lead to unwanted oxidation reactions. O2 can also have similar effects on metals such as iron. It can also be advantageous to control excess CO levels, as it is often produced from side reactions between oxygen and hydrocarbon gases but can be involved in ‘carbon reversal’ processes that lead to the production of soot.

Process Control

For heat treatment in endothermic conditions, it is therefore imperative to have highly controlled and monitored gas concentrations, as well as a way of monitoring potential fluctuations in the concentrations that are reliable over a large temperature range.

Non-dispersive infrared (NDIR) gas sensors are ideal for detection of a range of hydrocarbon gases and well suited for detection of many of the species involved in endothermic protection as they absorb IR light very strongly, making it a highly sensitive detection technique.

Furnace Sensors and Feedback

Edinburgh Sensors offers a range of gas monitors that are suitable for detecting one gas type at a time with built-in microcontroller processing to allow onboard corrections for changes in pressure and temperature conditions.

Suitable for detection of CH4, CO2, and CO, Edinburgh Sensors offers the GasCard NG and Guardian NG NDIR-based gas monitors. Both are highly sensitive monitors, capable of detecting CO2 concentrations between 0 – 5000 ppm and CH4 and CO levels between 0 – 100 %.

The Guardian NG offers an accuracy of ± 2 % across the full detection range and temperature compensation between 0 – 40 °C, while measurements are unaffected by humidity conditions in the 0 – 95 % relative humidity. The sensor is housed in an IP54 compliant casing which in addition comes with a convenient monitor for showing current and historical gas concentrations and built-in alarms that can be programmed directly on the device. The low response time (T90 < 30 s from sample inlet) means that the Guardian NG is ideal for providing continual monitoring and live feedback on even the smallest changes in conditions in the heat treatment chambers.

Casella’s VAPex Sampling Pump wins New Product of the Year award

Casella, air sampling, noise and vibration specialist, has won Occupational Health and Safety’s 2019 ‘New Product of the Year Award’ for its VAPex Personal Low Flow Sampling Pump.

Casella’s VAPex Personal Low Flow Sampling Pump was selected as the best new product in the Industrial Hygiene: Air Sampling category by a panel of three highly qualified judges.

Tim Turney, Global Marketing Manager at Casella, said “We’re thrilled that the VAPex has been recognised among this year’s best products by a publication as well regarded as Occupational Health & Safety. We’re proud that the user-focused features of the VAPex have put it ahead of other air samplers, following in the footsteps of our other award-winning products.”

The 11th edition of the annual awards program was highly competitive, as Occupational Health and Safety (OH&S) editor Sydny Shepard, explains: “OH&S’ ‘New Product of the Year Award’ saw an outstanding number of entries for 2019, proving that industry manufacturers are dedicated to producing products that optimise worker safety.”

To find out more about Casella’s full range of monitoring and sampling solutions, visit www.casellasolutions.com/uk/en.html

Biogas leakage – how to protect your AD plant from the silent killer

The UK’s anaerobic digestion (AD) industry has come a long way in a short space of time, growing by 350% in a decade to 648 operational facilities. Yet while many efficiency and health & safety advancements have been made across the industry in recent years, there remains room for improvement.


Identifying a biogas leak can prevent a serious incident from occurring

In particular, the issue of biogas leakage is one which many AD operators are still failing to address; often because the problem is invisible. However, the dangers associated with it – from diminished profits to environmental pollution and health & safety risks – should not be underestimated.

Here, Tim Elsome, General Manager for AD specialists FM BioEnergy, outlines the real cost of unidentified biogas leaks – and the inexpensive steps you can take to reduce the risks on your plant…

The scale of the problem

While most responsible plant operators will be monitoring key parameters such as temperature, digester biology and biogas production on a regular basis, the vast majority are not checking for gas leaks, believing it’s an issue which doesn’t affect their plant.

The evidence proves otherwise. Over the last eight years, 85% of the 964 plants we have surveyed in the UK and Germany were suffering from biogas leakage. A quarter of these were deemed ‘significant’ (>1,000l CH4/h), causing serious financial losses and safety concerns; half had only minor leakages (< 100l CH4/h); while the rest were deemed ‘medium’ (< 1,000l CH4/h). In most cases, more than one leakage type was present.

Translating this to the UK as a whole could mean that 550 plants are currently at risk; with 137 in danger of a serious financial or safety breach. Furthermore, if each of these 550 plants was to leak an average of just 0.5% of their capacity, it could equate to a potential loss of 37 GWhe-e a year, resulting in 6,000 tonnes of methane escaping into the atmosphere annually.

The risks of doing nothing

The implications of this volume of methane being released are significant. According to the latest IPCC Assessment Report, methane is 34 times more potent than CO2 as a greenhouse gas over a 100-year period. For any industry to be emitting this volume of methane would be a concern; but for a renewable sector, whose entire premise is based on being green, this is catastrophic.

A detection survey using a methane-sensitive monitor and laser, as well as infra-red devices, can spot biogas leaks invisible to the naked eye

Aside from the considerable environmental impact, biogas leaks bring other risks. In the worst-case scenario, biogas in combination with air can form an explosive gas mixture which, in a confined space near an ignition source, can result in explosion. While explosions are thankfully extremely rare, they bring a high risk of serious injuries and fatalities and, as a result, are something no plant owner ever wants to experience on their site.

Biogas also contains hydrogen sulphide (H2S), a toxic gas which has been the cause of a number of deaths in the UK agricultural industry in relation to slurry tank management. As H2S is heavier than air, it will fall to the ground. In confined, poorly-ventilated spaces it can accumulate and remain unnoticed until someone enters, resulting in sometimes fatal effects.

Gas leaks on AD plants also have a financial impact. Any volume of biogas leaking into the atmosphere will subsequently reduce a plant’s gas yield; and therefore, the owner’s profit margin. In fact, losing just 1m3 of methane per hour will result in a financial loss in the region of £5,000 per year.

There is also the issue of sustainability criteria to consider. In order to receive payments through either the Feed-in Tariff (FIT) or Renewable Heat Incentive (RHI) schemes, AD operators must demonstrate that their plant is operating sustainably. Regulators have considered clamping down on this area, as some industry reports mention very high levels of fugitive emissions. Site operators can therefore use gas leakage surveys as a way to protect against potential loss of incentives and demonstrate to the authorities that their plant is well-managed, with leaks kept to a minimum.

Leakage hotspots

While an AD operator may believe that their plant is operating at a high standard, all anaerobic digesters have inherent weak points which make them susceptible to biogas leakage. Potential hotspots include:

  • Gas membrane connections;
  • Cable grommets (where a submersible stirrer cable passes through the digester wall);
  • Flange connections;
  • Viewing windows;
  • Carbon filters;
  • Any areas where maintenance is carried out.

Reducing your risk

The risks of gas leakage are clearly significant and often expensive. However, identifying a leak is a simple and affordable process which can help prevent a serious incident from occurring. A gas leakage detection service should therefore form part of any responsible plant operator’s ongoing maintenance programme.

For example, the FM BioEnergy service covers a full AD plant survey with a methane-sensitive monitor and laser, as well as infra-red devices, including:

  • Survey of all tanks, CHP, biogas upgrading equipment, roof membranes, pipes and flanges;
  • Analysis of emissions from CHP and double-membrane covers;
  • Report with images, videos and repair priority table.

While the majority of our audits to date have uncovered minor leaks, 25% were found to have serious failings; fixing these not only prevents a more serious and costly incident from occurring, it often results in a 12-month payback on the price of the survey.

The best times to conduct a detection survey are at the start of full operation; after significant maintenance work; if your feed-to-gas conversion is lower than expected (and the biology remains stable); and of course, if you can smell biogas. After all, the cost of detecting a potential leak is minimal but the implications of leaving it to chance could be massive.

FLIR Systems completes strategic investment for quantifying gas emissions

FLIR Systems has made a strategic investment in Providence Photonics, developers of advanced software used to quantify invisible gas emissions using FLIR Optical Gas Imaging (OGI) cameras.

Providence Photonics specializes in the development and utilization of advanced technology in the field of optical gas imaging while tackling some of the industry’s most challenging environmental and safety problems. Using patented technology, advanced computer vision techniques, and state-of-the-art infrared imagers, they create solutions for several applications, including leak quantification, leak survey validation, autonomous remote leak detection, and flare combustion efficiency monitoring.

As part of the strategic investment, FLIR will gain exclusive access to certain elements of Providence Photonics’ intellectual property, while helping to expand FLIR Systems’ set of offerings to its oil and gas industry customers. The companies will work to deploy Providence Photonics’ quantification algorithms in current and future FLIR OGI cameras and digital services.

“Our investment in Providence Photonics represents another example of our evolution from solely being a leading sensor company to one that adds decision support to create intelligent sensing solutions,” said Frank Pennisi, President of the Industrial Business Unit at FLIR. “This investment enables to us to better serve our existing Oil and Gas industry customers who rely on our optical gas imaging technology to improve efficiency and safety, while ensuring compliance with methane mitigation regulations.”