System Integration & Control Systems Design


Safe burn off

January 2016 System Integration & Control Systems Design

Natural gas flare stacks are used in the petrochemical industry to burn off any gas that is produced in the production plant. These natural gas flare stacks process the flare gas and other exhaust gases, and ensure the safety and stability of the entire process.

Customer requirement

The plant of a major Chinese coal company produces 400 000 tons of acetic acid a year. Flare stacks play a particularly important role here in ensuring the safety of the entire plant. During the production of acetic acid, excess gases must be flared off during specific process incidents. Otherwise the entire plant would be facing an incalculable risk. Conventional natural gas required to ignite the gas flare is also present in the gas flare stack, as well as other explosive gases. Intrinsically safe electronic components must be used in the hazardous area at the flare stacks.

A wide range of different field instruments, such as pressure and temperature transmitters, level transmitters, gas detectors, valve controls, solenoid valves, and other instruments, are used at the gas flare stacks. In all, 44 measuring signals (sensor signals) and 39 control signals (actuator signals) have to be connected in the field to the DCS. In order to ensure the interference immunity of the signals, the customer required galvanic isolation of the individual signals.

The enormous safety relevance of the gas stacks meant that the plant owner placed a great deal of importance on the standard and quality of the electrical components used. However, these components also had to be cost efficient and easy to maintain in spite of the high level of quality and reliability required. The gas flare stacks required the use of intrinsically safe technology due to the explosion protection specified.

The customer also required a redundant connection for the communication between the flare stacks and the DCS. As the flare stacks were located far away from the DCS, it must also be ensured that the data reaches the control system fast enough and vice versa in spite of the long signal distance involved.

Perfect combination

The customer uses two excom remote I/O stations from Turck for the connection of the 83 signals of the gas flare stacks. The system fully meets all the customer›s requirements: The remote I/O station is compact, easy to install and can be implemented with explosion protection in Zone 1. excom can also be implemented with a redundant communication and power supply in order to provide the required level of failsafe performance. The customer was also impressed by the optocouplers used, which enabled the required communication speed to the DCS to be achieved. The optocouplers transfer the Profibus signal to the fibre optic cable for the long transmission section.

An excom station consists of the module rack, power supply unit, gateway and the individual I/O modules. With its diverse I/O modules the system offers outstanding performance and high channel density. With its safety barrier function, the I/O system can connect intrinsically safe field devices directly as the associated equipment. Unlike the standard I/O systems available which are isolated in groups, all I/O of excom come with integrated galvanic isolation for each individual input and thus provide the level of interference immunity required by the customer without the need for external signal isolators.

The excom system uses Profibus DP, a mature and reliable bus protocol which can transfer detailed diagnostic data as well as controlling and monitoring the field instruments. A redundant communication connection and power supply is provided throughout: starting with the power supply units and the gateways, to the optocouplers, right through to the redundant implementation of the DP communication modules of the DeltaV DCS from Emerson. If a field device fails, this is indicated by the DCS or the LED on the excom station. The technicians on site can swap the appropriate device during operation, which ensures that the communication with the field devices is absolutely reliable and fail-safe.

Conclusion

Compared to some other remote I/O solutions, the Turck option was more user-friendly, efficient and reliable for use at the gas flare stacks. The modular structure of excom reduces error sources and considerably simplifies maintenance as well as system expansion. These were the key benefits for the customer.

For more information contact Brandon Topham, RET Automation, +27 (0)11 453 2468, [email protected], www.retautomation.com



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Status display for conveying sensor, machine and device data
Turck Banner Southern Africa Operator Interfaces, Switches & Relays
Enhance application accuracy and efficiency with the SD50 Status Display, which conveys sensor, machine and device data via text and multicolour LEDs.

Read more...
Inductive IO-Link sensors
Turck Banner Southern Africa Sensors & Transducers
Turck Banner is expanding its sensor range, with inductive measuring sensors with IO-Link and an analogue output for flush and non-flush mounting.

Read more...
The state of the SI industry remains strong and is expanding
System Integration & Control Systems Design
The system integration (SI) industry is expanding with the adoption of AI, automation and data sharing, allowing companies to improve operational efficiency and competitiveness across diverse sectors.

Read more...
The symbiotic relationship between OEMs and SIs
Schneider Electric South Africa Editor's Choice System Integration & Control Systems Design
While businesses tend to turn directly to original equipment manufacturers OEMs or vendors when embarking on IT projects, the role of the SI as a key facilitator and partner cannot be overstated.

Read more...
Flexible and precise dispensing technology
Beckhoff Automation System Integration & Control Systems Design
The Scheugenpflug ProcessModule axis system forms the basis of Atlas Copco’s dispensing and screwing cells and a flexible integration platform for general contractors and machine builders. Precise process sequences are ensured by TwinCAT CNC and servo drive technology from Beckhoff.

Read more...
New toolset for Turck Automation Suite
Turck Banner Southern Africa Industrial Wireless
Turck is expanding its Turck Automation Suite IIoT and service software platform with the TAS Cloud industrial cloud service for remote maintenance and condition monitoring.

Read more...
Condition monitoring to go
Turck Banner Southern Africa Fieldbus & Industrial Networking
Anyone who wants to efficiently monitor the climate in control cabinets will find a comprehensive range of control cabinet monitors for the DIN rail in Turck Banner’s cabinet condition monitoring family.

Read more...
Compact UHF RFID reader with integrated Ethernet interface
Turck Banner Southern Africa Industrial Wireless
Online teaser: Turck Banner’s Q150 UHF RFID reader has an integrated Ethernet interface. The IP67 reader communicates directly with PC or PLC systems in industrial Ethernet networks having the four most important protocols, without the need for an additional interface.

Read more...
Monitoring voltage continuously
Turck Banner Southern Africa Electrical Power & Protection
Get a more comprehensive view of equipment and overall plant health while improving the accuracy of power calculations with Turck Banner’s new AC voltage sensor.

Read more...
Magnetic field/temperature sensor with IO-Link
Turck Banner Southern Africa Temperature Measurement
Turck Banner’s CMMT condition monitoring sensor detects magnetic field changes on three axes, and thus opens up new application fields.

Read more...