Operational excellence can be assured through the increased availability of gas analysis equipment via digital transformation.
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A wide range of industrial production processes depend on accurate, reliable, and stable gas measurements. These measurements are required to maintain safety, optimize operations, and adhere to regulatory requirements.
Gas analysis companies are delivering ongoing innovation in this area, but the solution to meeting ever more stringent gas measurement requirements could stem from developing technology and digitalization.
Today’s Industry 4.0 sees a combination of economic, competitive, and regulatory pressures, alongside the challenges arising from cultural and workforce shifts. These challenges are prompting a change in operations and a focus on operational excellence that is paying dividends, including the optimization of processes, assets, and people.
Top-quartile performers stand out in terms of safety, efficiency, reliability, sustainability, and financial performance versus those at the opposite end of the spectrum.
For example, top performers average a 4 % increase in operational availability, three times fewer recorded safety incidents, 50 % lower maintenance costs, and a 30 % reduction in emissions and energy use. These figures clearly highlight the importance of these factors in maximizing profits and margins.
Continued focus on operational excellence could be key to competitiveness and survival as the industry continues to pose a range of challenges. Operational excellence tends to result from thoughtful, focused, and incremental digitalization initiatives, including the improvement of situational awareness and the automation or streamlining of manual, error-prone, or slow activities.
It is possible to leverage low-cost sensing, data storage, connectivity, and processing in order to enable more informed and responsive operations and maintenance. This approach is also essential in delivering new levels of efficient asset management and optimization.
Offline Gas Analysis and Operational Excellence
A significant number of industrial processes are reliant on gas concentration measurements to support operational excellence objectives. Should these measurements become unavailable, the organization will likely see decreased operational revenue, increased operational costs, and increased operational risks.
An offline gas analyzer can increase operational costs because the process control system has less information on which to base adjustments. This ultimately results in the degradation of control, and while a process can continue operating and avoid a shutdown in most cases, it cannot run optimally.
Suboptimal processes may result in increased fuel or other resource use, higher energy consumption, adverse effects on other assets, and the incurring of additional overhead costs to bring the analyzer back online.
For example, reducing NOx emissions in combustion power plants (DeNOx) is typically achieved using selective catalytic reduction (SCR). This process involves injecting ammonia (NH3) into the gas stream from the combustion process, where it reacts with NOx in the flue gas in the presence of a catalyst to form H2O and N2.
The presence of surplus unreacted NH3, typically referred to as ‘ammonia slip,’ is both costly and wasteful, and may also result in harmful deposition effects that adversely affect the catalyst and can cause corrosion of downstream air preheaters.
An offline gas analyzer can also decrease operational revenue, with the resulting degradation in control capability potentially resulting in lower product yield, off-spec product quality, or even product scrappage.
For instance, ultra-pure gases are required for semiconductor wafer manufacture, and the smallest impurities in these gases can lead to major defects that necessitate product scrappage.
An offline gas analyzer also increases operational risks; for example, ammonia slip can cause an increase in harmful emissions that can have severe regulatory consequences.
Some processes also rely on accurate gas analysis to ensure safe operation. For instance, the process of combustion in control-fired heaters is integral to a number of hydrocarbon processes, and these heaters are extremely dependent on the reliable, continuous measurement of excess air.
A delicate balancing act is required to efficiently and safely operate larger, fuel-hungry units, such as those on ethylene crackers. This is necessary to maintain a balance between efficient, low-emission operating conditions without veering into potentially explosive low-oxygen and fuel-rich conditions.
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Factors Reducing Gas Analyzer Availability
It is important to ensure high gas analysis availability while balancing risk and cost. Reduced availability can occur due to a range of factors, however.
Issues around installation and commissioning can adversely affect tightly planned and coordinated construction, upgrades, and shutdowns. This may also result in delayed production start-up, potentially costing hundreds of thousands of dollars a day, including lost revenue and the need to reschedule dependent works.
Late delivery, poor installation, defective materials, and limited field access to information can all contribute to these delays.
Analyzer diagnostics can generally, but not always, detect exposure to unexpected process and operating conditions. Gas measurements may stop while the analyzer reports faults or out-of-specification indications to the plant control system, but this is dependent on the exact nature of the conditions.
The temperature, pressure, or flow of ambient or sample gas, rate of change beyond specification, excessive vibration, poor power supply, and electromagnetic interference are all examples of these types of conditions.
Specific gas concentration measurement technologies may also detect some conditions; for instance, high dust or particulate loading or unexpected background gases in the process gas stream can compromise spectral shape quality, impairing measurements acquired via Tunable Diode Laser Spectroscopy (TDLS). Some of these conditions may result in instrument damage, necessitating the purchase and installation of replacement parts.
Inadequate maintenance can also lead to degraded performance and ultimately to offline instruments.
For instance, sampling systems and analyzers typically include filters designed to protect the gas sensors from expected contaminants such as moisture and particulates, but it is necessary to clean or replace these filters periodically. Obscuration can build up over time on analyzers’ optics, even under expected operating conditions.
Analyzers must generally be taken offline for maintenance tasks such as cleaning optics, cleaning or replacing filters, or performing routine validation of measurement accuracy and any required calibration.
Incorrect operation of the analyzer, for instance, the inadvertent adjustment of critical configuration, can create effects that essentially render the analyzer offline or unreliable.
This may include altering or disabling the pressure or temperature compensation configuration, modifying assigned output behavior, or changing essential measurement details like the optical path length of an in-situ installation.
Unexpected component failures can also be detected and diagnosed to identify faulty parts. The nature of the faulty part in question will dictate its impact on the gas measurement and its availability to the control system.
Acknowledgments
Produced from materials originally authored by Tony Dodd from Servomex Group Limited.
This information has been sourced, reviewed and adapted from materials provided by Servomex.
For more information on this source, please visit Servomex.