A Single-Supplier Solution For Impurity Monitoring In Fuel-Cell Hydrogen

A Single-Supplier Solution For Impurity Monitoring In Fuel-Cell Hydrogen

Global efforts to reduce the impact of harmful emissions on the environment have increasingly focused on lowering carbon emissions.  The key to meeting this challenge lies in replacing fossil fuels with alternative, renewable fuel sources, particularly to power vehicles.

Fuel cells offer a uniquely flexible solution in this market and can be used for a wide range of applications, powering systems from laptop computers to utility power stations.

The move to a hydrogen economy is widely regarded as the next step in the global transition towards a zero-emission energy sector. A hydrogen fuel cell uses chemical energy to cleanly and efficiently produce electricity; the only byproducts are water and heat. It can also be combined with electric motors to power a zero-emission vehicle.

While most hydrogen (H2) today is still produced from fossil sources, an established H2 infrastructure allows a future seamless transition to renewable and truly carbon-free H2 production. Fuel cells are also far more efficient than conventional combustion engines while offering a similar range (typically, about 500-700 km). H2 can also be refilled quickly at a fueling station, avoiding the delays of charging a battery-electric vehicle.

However, the performance of a fuel cell is dependent on the purity of the hydrogen. There are multiple impurities that can affect the fuel cell, and their presence and concentration levels depend largely upon the method used to generate the H2.

For example, most hydrogen is produced through steam methane reforming. This process can generate several contaminants ranging from methane and moisture to carbon monoxide and carbon dioxide (CO2). If H2 is created through electrolysis, splitting water into hydrogen and oxygen, then moisture and oxygen are the most common contaminants. Additionally, many impurities can come from the atmosphere, mostly nitrogen, oxygen, and moisture.

Eliminating impurities from H2 altogether is not practical. Maintaining an efficient fuel cell requires the presence of these contaminants to be limited to specific levels, set by international purity standards such as ISO 14687 or SAE J2719.

It is essential to monitor the wide range of impurities listed in the table above to prevent performance being compromised, or worse, irreparable damage to the fuel cell.  In the past, a monitoring solution for H2 purity involved a complex setup using as many as seven different analyzers from multiple providers, with no integration.

A typical arrangement requires:

  • A gas chromatograph for total sulfur and total halogenates
  • Another gas chromatograph for helium, nitrogen & argon, and methane/THC
  • An electrochemical analyzer for oxygen
  • An FTIR to measure CH2O2, CO and CO2
  • Three separate CRDSs, measuring water, ammonia, and CH2O

Process Insights provides a full portfolio of solutions for monitoring hydrogen purity throughout its supply chain, from production, through transport and storage, to fueling.  The contaminant detection limits of these instruments are ideally suited to qualify H2 for compliance with global purity standards.  The real benefit, however, lies in Process Insights’ total solution, which links products from its Extrel and Tiger Optics brands.  Only three analyzers are required, and these can be fully integrated into one single-provider system.

The components are:

The Prismatic 3 multi-species Cavity Ring-Down Spectroscopy (CRDS) analyzer allows simultaneous detection of up to four impurities with wide dynamic ranges, delivering simple, real-time, direct measurements. Highly reliable and with low maintenance requirements, the Prismatic 3 is ideal for remote operations and has a low cost of ownership.  Tiger Optics’ analyzers are used to support fuel-cell hydrogen quality control by organizations including the Korean Gas Safety Corporation (KGSC) and California’s Division of Measurement Standards and is approved by ISO.

The MAX300-LG is a compact benchtop mass spectrometer that delivers complete, real-time sample analysis from 100% concentration down to parts-per-billion (ppb) levels. It is supported by our Extrel easy-to-use Questor5 process control software, which is designed for continuous gas monitoring with automated calibrations, analysis sequences, and data outputs.

The combination of Process Insights’ Prismatic 3 analyzer and MAX300-LG mass spectrometer with a Sulfur & THC GC Analyzer to provide the remaining measurements provides a powerful solution for monitoring contaminants in fuel-cell hydrogen.

This system dramatically reduces the number of instruments required for measuring hydrogen samples and reduces the cost of manpower and operation through ease of use and low maintenance needs. It also means operators only deal with a single provider, reducing the complexity of ordering, integration, and usage.

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Parts-Per-Trillion Moisture Detection in Electronic-Grade Bulk Gases

Parts-Per-Trillion Moisture Detection in Electronic-Grade Bulk Gases

The semiconductor market is seeing a new era of innovation, with new applications fueling demand for advanced semiconductor devices that put more stringent requirements on reliability, power handling capability and power consumption, while packing more functionality into a smaller package and decreasing technology nodes.

Among these demanding applications are increasingly more powerful smartphones and tablets that aim—at the same time—to improve battery life. More recently, automotive sensor systems, the Internet of Things (IoT), the next generation of wireless communication (5G), and smart power grids have emerged as applications with enormous expansion potential over the coming years and decades. Future self-driving vehicles, for instance, require massive amounts of computing power to process the input from cameras and sensors in real-time; and the necessary high-performance processors must be both reliable and power efficient.

The Demand for Higher-Quality Gases and Better Analytics
To meet the challenges of these new applications, the semiconductor industry’s International Roadmap for Devices and Systems (IRDS) outlines manufacturing quality as one key aspect; therefore, semiconductor device manufacturers are implementing more stringent control into all aspects of the manufacturing process, from the cleanroom environment and the wafer processing tools to the raw materials used for production, many of which are gases. Consequently, improved gas quality control is one of the most important measures that are employed by semiconductor fabs to increase yields and reduce failure rates.

With the need to monitor and ensure stricter and more consistent gas quality comes a demand for more sensitive and accurate analytical technologies. At the same time, speed of response has become more important as well, as fab operators rely heavily on real-time process control to

In many state-of-the-art semi fabs, Cavity Ring-Down Spectroscopy (CRDS) analyzers are the gold standard for ensuring quality of the major bulk gases that are used in the manufacturing process, which are typically N2, CDA, O2, H2, Ar, and He.

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HCl Continuous Emissions Monitoring

HCl Continuous Emissions Monitoring

Hydrogen Chloride (HCl) is a major atmospheric pollutant associated with the combustion of fossil fuels, such as coal and heavy oils, and also with a number of manufacturing processes, including cement production.

HCl in the atmosphere has an adverse effect on both human health and the wider environment. The inhalation of even low concentrations of HCl can cause irritation of the respiratory tract in healthy individuals and exacerbate symptoms associated with conditions such as asthma and emphysema.

Dissolved HCl is a contributor to acid rain pollution, the results of which include damage to building materials and reduced crop yields.  Atmospheric HCl pollution is also a factor in the production of photochemical smog. The economic impact makes the reduction of HCl pollution a priority for regulators and industry. HCl is generated by multiple industrial processes, with combustion of coal and oil for household and industrial power generation as the primary source. Here, chlorides present in the fuel are converted to HCl in the combustion process and emitted with other by-products. In addition, industrial processes emit HCl as a result of chlorides present in raw materials that are converted to HCl during production. In cement production, for instance, raw materials, including calcium carbonate, silica, clays, and ferrous oxides, all contain chlorides, resulting in generation of HCl.

Regulators worldwide dictate strict emissions limits for many atmospheric pollutants, including HCl. In the United States, the Environmental Protection Agency (EPA) has recently reduced emissions limits to further lessen the impact of the issues.  These emissions limits require HCl emitters to monitor and report the level of the gas present in stack emissions and to ensure that steps are taken to guarantee that emissions fall below the specified limits. This may require the emitter to either refine their process, via the use of cleaner fuels, for example, or to add abatement technology downstream of the process to reduce emissions of HCl.

Current analytical methods for HCl CEM applications include GFC/NDIR, FTIR, and cross-stack TDLAS. These methods have, to date, been adequate to monitor HCl emissions, based on existing emissions limits. The detection limits for some of these techniques will not be sufficiently low, however, to meet the revised limits, and so alternative techniques will be necessary.

CRDS offers the performance and range to cope with these regulations, delivering accurate measurements at levels far below the new limits in diluted stack gas.

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Next-Generation Monitoring of Airborne Molecular Contaminants in Cleanrooms

Airborne Molecular Contaminants in Cleanrooms

Airborne Molecular Contaminants in Cleanrooms

The dust-free and controlled environment of a cleanroom is vital to prevent product failure in semiconductor manufacturing but controlling particulates in cleanrooms is not nearly sufficient to protect semiconductor devices that feature structural sizes on a molecular level. Micro-particles are the main source of physical contamination, but modern filtration systems for air supply, cleanroom attire and specialized surface materials have been successful in keeping particle contamination under control.

There are, however, molecular contaminants, which can range from small inorganic molecules like acids and bases, to more complex organic species like VOCs. These molecules are known to cause chemical contamination, i.e., they react with the materials and surfaces of the semiconductor devices to cause oxidation, unintended doping, dislocations, and more.

This class of contaminants is collectively known as Airborne Molecular Contaminants (AMCs). They are harder to control than particles. Firstly, the molecules are much smaller than particles and require more advanced chemical filtration of the cleanroom air. Secondly and more importantly, however, many AMCs are created within the cleanroom itself. For instance, HF is used for wafer cleaning within the process, and NH3 is emitted naturally by any person present in the cleanroom. As feature sizes have decreased over the decades, both devices and equipment became more and more susceptible to significant damage from AMCs. They can have various detrimental effects: Acids, such as HF or HCl, can cause micro-corrosion and accelerate oxidation. Bases, such as NH3, can cause hazing and attack coatings on the optics of UV lithography equipment. Hydrides, such as AsH3, PH3, or B2H6, can cause unintended doping, which can dramatically impact a devices functionality.

Monitoring AMCs is Key to Contamination Prevention
Because many AMCs are generated within the cleanroom, they cannot be completely avoided, even though wafers are shielded as much as possible from exposure nowadays, e.g., by transporting them in closed pods (FOUPs) between process steps. Precise monitoring of the cleanroom environment for these molecules has emerged as a key for semi fabs to further mitigate the threat of AMCs. By immediately detecting the presence of harmful molecules, engineering controls can be implemented to protect devices and processes from exposure.

Due to the low concentration of AMCs and the need for fast detection, measurement instruments have to fulfill stringent requirements. As a result, ultra-sensitive laser-based analyzers have emerged as the primary class of instrument used to detect small AMCs, such as HF, HCl or NH3. Semiconductor fabs require all of these molecules to be measured at levels below 1 part per billion (ppb) with a response of 1-3 minutes to any presence of molecules. More importantly, the instruments readings have to return to baseline as fast as possible after the molecules’ presence is eliminated to minimize delays in the manufacturing process. The International Roadmap for Devices and Systems (IRDS) even calls out detection requirements below 0.1 ppb as part of the future technological challenges.

Introducing the T-I Max Next-Generation AMC Monitors
To address this challenge, Process Insights manufacturers the Tiger Optics T-I Max series of cleanroom analyzers for detecting AMCs like HF, HCl, and NH3 with unprecedented speed and sensitivity. The T-I Max uses powerful Cavity Ring-Down Spectroscopy (CRDS) Technology but uses an all-new electronic and optical platform that enables lower measurement noise and up to ten times faster measurement rate. This platform takes CRDS to the next level and dramatically lowers detection limits compared to previous generation analyzers.

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Cost-Effective Purity Analysis in the Cryogenic Air Separation Process

Cost-Effective Purity Analysis in the Cryogenic Air Separation Process

Did you know you can improve safety and your process efficiency with CRDS analyzers?   

CRDS analyzers offer many opportunities to improve the air separation process by saving time and money, and alerting plant operators quickly in case of unsafe impurity levels.

Key advantages of CRDS analyzers include:

  • Freedom from calibration
  • No consumables or service gases required
  • All solid-state design, no moving parts
  • Plug-and-play, easy to operate
  • Accurate detection of H2O, CO2, CH4, C2H2 and H2
  • Fast speed of response, ideal for process control

Cryogenic Air Separation
Cryogenic air separation units (ASUs) are the gas industry’s workhorses for the production of gaseous and liquid high purity nitrogen, oxygen and argon. The cryogenic process can be modified to manufacture a range of desired products and mixes.

Controlling Impurities to Ensure Safe ASU Operation
Following compression, the air pre-treatment step consists of cooling and purification to remove process contaminants, such as H2O, CO2 and others. The most common purification methods are Temperature Swing Adsorption (TSA), which exploits the difference in adsorption capacity of adsorbents at different temperatures, and Pressure Swing Adsorption (PSA), which operates similarly via pressure variations.

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Validating CRDS for Moisture Analysis in Medical Oxygen

Validating CRDS for Moisture Analysis in Medical Oxygen

Medical oxygen is one of the most commonly used gases in the healthcare industry, from giving O2 to critical care patients, providing the basis for anesthesia, to supplementing O2 to patients with chronic lung diseases, such as COPD.

To ensure that the oxygen meets the necessary quality to prevent harm to patients, strict standards outline limits to a variety of possible impurities in the gas, one of them being water vapor (H2O). One of the most common standards for medical oxygen is the European Pharmacopeia (EP) standard, we will demonstrate analytical equivalency between the Process Insights’ Tiger Optics’ Spark Cavity Ring-Down Spectroscopy (CRDS) analyzers and demonstrate analytical equivalency to traditional electrolytic moisture analyzers, so the Spark can be used as a more modern and powerful alternative.

Proving Equivalency to European Pharmacopeia
The EP standard dictates that the maximum water vapor content in medical and pharmaceutical grade gas must be less than 67 parts per million (ppm), and the recommended method for analysis of moisture content in medical gases is electrolytic based sensors. Since this standard was published in 1999, gas manufacturers have significantly improved their process efficiency, resulting in considerably higher purity product; at
the same time, the state-of-art in analytical technologies for moisture measurement has evolved. The combination of improved analytical capabilities and higher purity product creates an opportunity for gas manufacturers to maximize the return on oxygen by qualifying it for multiple uses in a single validation step.

Based on powerful, proven CRDS, the Process Insights‘ Tiger Optics Spark H2O offers a wide dynamic range, from single-digit parts-per-billion to one thousand ppm for analysis of moisture in oxygen. This low-cost, fast and accurate analyzer features self-zeroing and auto-verification, eliminating the need for field calibration and saving time & money on labor and consumables. In addition to qualifying oxygen, the same analyzer can service nitrogen, argon, helium, hydrogen, clean dry air, and many other gases and mixtures. In support of the proposed use of the Tiger Optics Spark for qualification of medical oxygen, we present the following validation data, demonstrating equivalency in accuracy of the Spark H2O with two EP-approved electrolytic moisture analyzers.

The Tiger Optics Spark analyzer allows accurate measurement of moisture in oxygen to within ±4% or 6 ppb, whichever is greater, as clearly demonstrated in the present validation data. Thereby, it demonstrates equivalency with the European Pharmacopoeia standard, which mandates a relative accuracy of less than ±20%. Plus, the Spark affords a significant performance advantage over the incumbent electrolytic based sensors, including lower detection limits, wider dynamic range, higher accuracy, and faster speed of response. This allows for better throughput and simplified product qualification, ultimately saving end-users time and money. It should be noted that the ability to conduct one-step qualification of pure oxygen for multiple applications provides significant value to users.

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Accurate Online Analysis of Helium Tube Trailer Filling

Industrial gas manufacturers package and deliver gases in a variety of different ways. These include on-site pipeline distribution, bulk delivery of liquefied gas into an on-site bulk container, exchange programs for large, compressed gas vessels (i.e., tube trailers), and delivery of smaller cylinders containing gas or liquefied gas.

Each delivery mechanism has unique advantages, but also unique associated costs. Here we describe the requirements and challenges of tube trailer filling, detailing the needs related to filling high purity Helium into tube trailers and showing that the Process Insights’ Tiger Optics Spark H2O analyzer can offer a perfect solution for detecting trace moisture in this application.

Challenges of Helium Filling
Helium tube trailer filling is a demanding activity with relatively high cost and process complexity. “Crude” Helium is harvested in geographic locations that have Helium-rich natural gas fields, which mostly include areas in Algeria, Australia, Canada, Poland, Qatar, Russia, and the United States. It is delivered to industrial gas packaging facilities around the world as a bulk cryogenic liquid in 11,000-gallon refrigerated ISO tankers. The bulk liquid is not thermodynamically stable and must be quickly and efficiently transferred to more stable product forms (i.e.,
pressurized gas) with longer storage potential. This is typically accomplished by decanting off some of the liquid into smaller Dewar vessels for immediate sale and use and gasifying and compressing most of the Helium for filling pressurized vessels (compressed gas cylinders and “tubes”).

In recent years, Helium has become short in supply numerous times. As a result, Helium prices have doubled in the last decade and are routinely exceeding $200 per thousand standard cubic feet (SCF). Therefore, efficient management of Helium processing and minimization of product loss directly affects the profitability of the enterprise. Additionally, Helium tube trailer filling is a time-consuming process, taking at least 14 hours for a successful fill of the largest tube bundles (180,000 SCF). With respect to other activities at packaged gas facilities, a relatively large investment in time and product value is made for Helium tube trailer products.

Typical Helium tube trailer filling operations perform several steps including gasification, compression, purification, and tube filling (schematically outlined in Figure 3). The goal is to fill the trailer tubes in the most energy and time-efficient manner possible, and there are several points where making a fast, accurate moisture measurement can assist in achieving this goal.

The major monitoring points of interest are:

  • Incoming Helium Product: Incoming crude Helium is typically too wet to be packaged without some purification. Moisture measurements made on the crude Helium allow optimization of purification procedures.
  • Post-Purification: Purification processes typically include a selective adsorptive bed that can saturate with moisture and other impurities. Once saturated, the bed loses its capacity to retain any additional moisture and it must be regenerated. The active lifetime of the bed is a function of the moisture level in the incoming gas stream and the total time of usage. Monitoring the purification system output stream helps to indicate the active lifetime of the bed between regenerations.
  • Tube Trailer Inlet: Most crucially, monitoring of the Helium product as it enters the tubes assures that the tube trailer is filled within specification product. Moisture measurements made at the point of fill will detect any quality defect stemming from bad product, inadequate
    purification, or compromised transfer lines. Since the fill is accomplished over such a long period of time, small variations in the moisture levels can indicate to an operator that minor process adjustments should be made. For example, an upward-shifting moisture level could indicate that the purification must be slowed, to better extract the moisture.

Traditional moisture measurement technologies have some drawbacks for these applications. Most demonstrate slow response time, limited range, and a high degree of signal averaging, which can miss a moisture excursion. At minimum this can lead to energy waste in the process, and in the worst case an entire tube trailer can be filled without specification product due to a missed moisture spike.  Lack of ability to change sampling points is another issue with traditional technologies. To switch from crude product to purification or final fill sampling points, the analyzer needs to be disconnected and the inlet exposed to ambient for a short period. Most technologies would experience saturation in this situation and take hours or even days to dry down again sufficiently to perform the next measurement.

Improving Measurement with the Spark
For each of the measuring points highlighted above, the Process Insights’ Tiger Optics’ Spark H2O analyzer is optimally suited to make the measurement. The absolute accuracy offered by Cavity Ring-Down Spectroscopy (CRDS) is a key advantage. There is also no requirement for a zero
gas or a span gas.