PTQ Q2 2023 Issue

case, this would mean cooling flue gases below the acid dew point. If operating with sacrificial heat recovery equip - ment is not the real intent, it is prudent to take caution while deciding on the stack temperature set values and revisit them periodically every time fuel undergoes a change. Conversations such as these paved the way for a digitisa- tion initiative in fired heaters through EngRT-Htr. It is clear that the fired heater market needs the ‘knowledge’ to oper - ate heaters ‘more effectively and efficiently’. A solution was to put this feedback into one common platform to analyse the current operation and recommend changes for further trimming. The developed digital tool can empower the user to overcome understandable inertia and utilise all available improvement potential in existing asset operation. Software features The digital platform works on a robust data structure that allows the refiner to feed in the current operating data as well as fuel and ambient conditions at any point in time. EngRT-Htr, through its optimiser module, analyses the oper - ating data and makes refinery operators aware of various hardware-related actions and re-adjustment of operating set points to maximise furnace efficiency (see Figure 3 ). Additionally, the digital intervention addresses hardware limitations that may prevent further optimised operation and plays a dual role in preventive maintenance of fired heaters in refineries. This unique feature makes a refiner aware of lost opportunities due to hardware limitations. Hardware limitations in reaching the maximum efficiency improve - ment potential could be due to the underperformance of the existing setup or less than required heat recovery equipment area availability. In both cases, improvement potential iden- tification paves the way for making a well-informed decision regarding future capital investments. For a broader outreach, the software has been devel- oped as a ready-to-use web version that can be accessed from any secure server connection, providing the flexibil - ity to optimise from anywhere and at anytime. Currently,

Ensures heater operation in safe zone Helps in extending the life of heater components Preventive maintenance

Optimising red heaters for current operating parameters Adapting to changes

Identies and highlights opportunities Forms basis for further capital investment Hardware limitations

Real - time optimisation

Figure 3 EngRT-Htr features

and fuel gas, with appreciable heat input from fuel gas. It is observed that such recommendations are not read- ily accepted. In this case, the supervisor insisted, “We are operating correctly. We have been keeping oxygen at arch level at 4.0 vol% for decades.” As per global engineering practices, varying O 2 require- ments for combination fuel firing are not included in typical operating instructions. The point being addressed here by the refinery was that the excess O2 vol% being maintained was appropriate for heavy fuel oil firing. However, as the refinery had moved to comparatively lighter oil with more than 50% heat from fuel gas, there was scope for improve- ment. All it had to do was change the airflow settings and gain some percentage points in efficiency. Sometimes the story can be reversed. Those providing services for fired heater revamps are often asked to trou - bleshoot corrosion issues in flue gas heat recovery equip - ment or ID fans. This is often a case where flue gases are cooled to such an extent that equipment safety seems to have taken a back seat against an attractive efficiency fig - ure. To keep up with ever-changing market dynamics, some refiners are trying to bring their furnace stack temperatures in sync with the latest trend of 110-120°C. For the oil firing

EngRT-Htr Dashboard Look

Figure 4 EngRT-Htr output card

PTQ Q2 2023