Revamps 2023 Issue

Before Turnaround

After Turnaround

890

~5 Gcal/hr Firing duty decrease under the same throughput

860

830

21˚C lower weighted average BWT

Fuel ring, Gcal/hr Weighted average BWT, ˚C

800

Time (hours)

Figure 5 Weighted average BWT and fuel firing before and after the Cetek application

was carried out. Figure 4 vividly illustrates the noticeable distinction between the uncoated cell and the coated ones. As an additional advantage, the heat distribution along the length of the tubes became more even. Moreover, deter- mining tube metal temperature through IR thermography became possible, owing to the well-established ΔT (tem - perature difference) and a constant emissivity value attrib- uted to the coating. Data trends on energy efficiency Data trends on BWT, excess air, combustion air tempera - ture, and fuel consumption were analysed for periods before application and two months after application (see Figure 5 ).

After the application, BWTs were lower than before. These lower BWTs led to a fuel consumption decrease under the same throughput. A weighted average BWT reduction of 21°C and fuel savings reduction of circa 5.0 Gcal/hr were observed. Full evaluation results The initial full data set was collected before the turnaround and compared with data after application. Process data (see Table 1 ) shows that the application has improved radiant efficiencies and debottlenecked the fired heater limitations. The Cetek coating application has accomplished the objectives of increasing fired heater effi -

ciency and protecting process tubes from corrosion and oxidation, thereby prolonging tube service life. Data from a year before the application was selected as a base case condition due to the established throughput and similar weather conditions with the post-application case after the pro- ject’s execution.. This project has provided an imme - diate economic benefit and long- term reliability for the refinery. It has achieved 13.2% of fuel savings under the same production or a correspond- ing production increase under the same fuel firing potential. Based on the fuel consumption reduction, the estimated CO 2 savings are circa 9,600 MTPA accompanied by thermal NOx emissions reduction due to lower radi- ant box temperatures. The benefit (in Gcal/hr fuel savings) is very similar to the benefit after other independent modifications (see Table 2 ).

Cetek Evaluation Results

Parameter

Before Turnaround After Turnaround

Throughput (hydrotreated naphtha), % of design

100

H 2 :HC ratio, mole/mole Heaters combined ΔT, °C Total absorbed duty, Gcal/hr Fuel consumption, Gcal/hr

1.8

1.7

211.2

213.8

Base case Base case

Base case – 0.2 Base case – 4.7 Base case + 6.4

Apparent radiant efficiency (interheaters only), Δ% Base case

Achieved fuel savings (interheaters only), %

–

13.2

Table 1

Cetek Ceramic Coating and Independent Modifications Results Comparison

Table 1

Parameter

Before Turnaround

After Turnaround

Throughput (hydrotreated naphtha), % of design

100

H 2 :HC ratio, mole/mole

1.8

1.7

Fresh BFW consumption, vol. flow Charge heater inlet temperature, °C Charge heater bridgewall temperature, °C Fuel consumption (charge heater), Gcal/hr Fuel savings (by ceramic T&R coatings), %

Base case

Base case – 35%

414 842

444 647

Base case

Base case – 5.0

– –

48.4 51.6

Fuel savings %

Table 2

Revamps 2023