Revamps 2022 Issue

Figure 4 Automation of existing air devices

• Corrosion or fouling problems • Produce tubes overheating and coking • Jeopardising unit operational safety.

Monitoring of combustion air is performed by four O 2 probes, two placed at each cabin, at the North and South walls. Burners are equipped with manual secondary air regulation capabilities, and one manual draft damper, located after the crossover, is used for overall combustion air control. Excess O₂ has been historically controlled at around 4.0-4.5%. Specific configuration of applied technology ABACO technology was implemented in the crude oil unit with the objective of improving the combustion control capability and reaching optimised operating conditions. Application of the technology to this unit includes the fol- lowing capabilities (see Figure 6 ): • ABACO-Opticom monitoring system, including 80

Acquiring the capability to identify these bespoke operat- ing issues makes possible the supervision and optimisation of operating conditions for all load scenarios and changing conditions, such as co-firing and the use of different fuels while maintaining adequate control of safety limits. Regulation capabilities improvement Optimised operating scenarios are performed by the improvement of the fired heater regulation. These include: • Automation of existing manual regulations from the con- trol room, including both burners and draft dampers (see Figure 4 ) • Revamping of existing equipment, such as burners or wind box, to increase the tuning potential. Expert system for optimised combustion control Management and optimisation of the combustion process is performed through ABACO Control System. This is based on flexible control architecture, incorporating ABACO-Opticom technology and the existing and new regulation devices. Closed-loop control is implemented within an Expert System, individually configured by INERCO, for each com - bustion unit based on specific testing and combustion exper - tise. The Expert System continuously analyses and oversees that the conditions of the combustion process are safe and always controls critical process variables of the unit. Case study: characterisation of target facility The target facility is a double cabin-fired heater with opera - tion based on crude oil duty requirements. Typical fuels are refinery fuel gas, in a wide variety of proportions depending on overall refinery fuel gas balance, and natural gas. The fired heater is equipped with 80 horizontal gas burn - ers, 40 per cabin, placed in two opposite rows (see Figure 5 ).

Draft damper, manually controlled

Excess O analyser, only in exterior bands

Horizontal burners

Figure 5 Fired heater general scheme

Revamps 2022