ERTC 2024
Reliable laser-based gas analysis for enhanced process safety and efficiency
Sophia Asal ENDRESS+HAUSER
Now more than ever, European refiners are facing challenges due to shifting mar- ket dynamics and strong competition while also under pressure to comply with stricter environmental guidelines and standards. Maintaining plant uptime, improving effi- ciency, ensuring process safety, and pro- ducing high-quality products has never been more critical to staying competitive. A key aspect of meeting these obsta- cles is desulphurisation. The removal of sulphur not only prevents the formation of harmful sulphur oxides (SOx) during fuel combustion but also enhances fuel qual- ity by improving combustion efficiency and reducing the risk of particulate matter in engines, such as diesel engines. In addi- tion, sulphur compounds are highly cor- rosive and can cause significant damage to refinery equipment, resulting in higher maintenance costs and reduced opera- tional efficiency. Hydrodesulphurisation (HDS) can effectively reduce sulphur con- tent, enabling refineries to meet stringent environmental standards and emission lim- its while maintaining process reliability and product quality. hydrodesulphuriSation process As a crucial process unit in oil refineries, HDS ensures the removal of sulphur com- pounds from liquid hydrocarbon streams to reduce sulphur content in fuels, such as gasoline, diesel, jet fuel, and other refinery products, to meet environmental regula- tions and prevent corrosion in pipelines or poisoning of catalysts. High availability and reliability are mandatory to guarantee safe operation in the HDS process. The preheated feedstock (crude oil frac- tions like gasoline, diesel, kerosene or heavy oils) is mixed with hydrogen gas and then fur- ther heated to 300°C to 400°C. The mixture is fed into the HDS reactor, which operates under high pressure of up to 100 bar and contains a solid catalyst (usually NiMoS/ Al₂O₃ or CoMoS/Al₂O₃). This catalyst helps in facilitating the hydrogenation reactions: the hydrogen (H₂) reacts with the sulphur com- pounds to produce hydrogen sulphide (H₂S) and desulphurised hydrocarbons (R-H). After the catalytic reaction, the mixture leaves the reactor and enters a separation section. Hydrogen sulphide (H₂S), which is now a gaseous byproduct, is separated from the desulphurised liquid hydrocar- bons. This separation is typically done in a gas-liquid separator. Unused hydrogen from the reactor efflu- ent is usually recycled back into the system for efficiency, while the desulphurised prod- uct moves on to further refining or distribu- tion. In the HDS process, H₂S is removed from the hydrogen using an amine unit before the hydrogen is recycled. importance of monitoring Gas analysis plays a critical role in the HDS process by monitoring and controlling var-
differential spectroscopy technique enables the detection and quantitation of low ppm levels of H₂S in hydrogen recycle gas. Laser and detector components are isolated and protected from process gas and entrained contaminants, avoiding fouling and corro- sion, ensuring stable long-term operation and accurate measurements. In HDS appli- cations within the refining market, these TDLAS analysers are used to monitor the hydrogen quality to ensure there is no resid- ual H₂S, as it can poison the catalyst. Endress+Hauser’s newest JT33 TDLAS gas analyser is particularly robust and reli- able, providing continuous, real-time H₂S measurements, even in the presence of contaminants, across both light and heavy streams. Its superior accuracy and repeat- ability are ensured by proven metrology and National Institute of Standards and Technology (NIST)-traceable factory cali- bration, delivering consistent results veri- fied by on-site auto-validation. With Endress+Hauser Heartbeat Technology, the JT33 offers 24/7 monitor- ing of the analyser health. It also features auto-stored historical data, spectrum log- ging, diagnostics, and verification report- ing for complete system transparency. Downtime is minimised thanks to field- serviceable and interchangeable compo- nents, allowing for quick repairs without recalibration. Additionally, the system’s minimal consumables further maximise operational uptime. The JT33 is designed for ease of use, featuring a user-friendly interface with an intuitive menu. Setup and operation are accessible remotely via integrated web server software, ensuring smooth and effi- cient operation at all times. Summary In conclusion, the JT33 TDLAS gas ana- lyser is an indispensable tool for real-time monitoring in the refining industry. Its appli- cation in the HDS process is critical for meeting environmental regulations and pre- venting issues such as pipeline corrosion and catalyst poisoning. The high availability and reliability of the JT33 ensure safe and efficient operation, reducing failures and operating costs. By enhancing the safety and integrity of refinery operations, this technology not only protects asset investments but also provides a sustainable competitive advantage in the mar- ket. Moreover, the JT33’s advanced features, such as continuous real-time H₂S measure- ments, robust design, and user-friendly inter- face, make it a preferred choice for refineries aiming to optimise their processes. This com- prehensive approach to gas analysis not only supports compliance with stringent environ- mental standards but also drives operational excellence and long-term sustainability in the refining sector.
DID you know? The high availability and reliability of the JT33 TDLAS ensure safe and efficient operation, reducing failures and operating costs pected increase in H₂S may indicate that the catalyst is deactivating, requiring regeneration or replacement. Gas analysers further provide real-time data, allowing for immediate adjustments to process variables and helping optimise the HDS process for maximum efficiency. advantages of TDLAS gas analysers Endress+Hauser’s tunable diode laser absorption spectroscopy (TDLAS) analys- ers, based on SpectraSensors technol- ogy, are proven to be highly effective in H₂S measurement. They have an extremely fast response to changes in H₂S concentra- tion, allowing operators to intervene quickly when necessary. The company’s patented
ious aspects of the operation to ensure efficiency, safety, and compliance with environmental standards. H₂S is the main byproduct of the HDS reaction. Its concen- tration in the gas stream of the recycled hydrogen needs to be closely monitored to ensure the separation process is working effectively and to avoid catalyst poisoning. By analysing the gas composition (for example, the levels of H₂S and other gases), operators can assess the perfor- mance of the HDS catalyst. A decrease in sulphur removal efficiency or an unex- Figure 1 The JT33 TDLAS gas analyser ensures highly accurate, continuous, real- time H₂S measurements
Sour gas
Hydrogen make-up
Recycle hydrogen
Rich amine
Stripper/ fractionator
Sour water Light ends
Pre-heater
HDS feedstock
Heater or furnace
Hydrogen separator
Desulphurised product
Figure 2 Hydrodesulphurisation process
Figure 3 Refineries must meet standards and specifications and comply with regulations
Contact: sophia.asal@endress.com
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