performance of HP ThermoPro under these varying process conditions. HPCL’s refinery in Visakh processes crudes that are high in sulphur, low in sulphur, and asphaltenic. Field trials were carried out at the refinery from March 2019 to February 2020, focusing on both high-
Trial commencement
270
Low sulphur
High sulphur
260
250
240
230
Month
Figure 2 Field trials at HPCL Visakh Refinery
The temperature drop at the outlet of the tube over the run time was taken from the RPFS run results and is directly indicative of the effectiveness of the antifouling formulation. The lesser the temperature drop, the more effective the antifoulant. The results of control experiments (w/o antifoulant), benchmark antifoulants, and HP ThermoPro against crude oils, crude blends, DHDS feed, and short residue are presented in Table 4 . The shown values are temperature drop ( ∆ T) in ºC. From the results, it is evident that the in-house developed antifoulant formulation, HP ThermoPro, exhibited superior performance in comparison to control experiments and benchmark antifoulants. Importantly, it works effectively across all types of crudes, crude blends, DHDS feed, and short residue. Field trials at HPCL refineries Following a successful demonstration at the lab scale, HP ThermoPro was scaled up to tonnage levels, and field trials were conducted at HPCL refineries in both Mumbai and Visakh. These trials were carried out over an extended period to account for variations in preheating related to different crude types and process parameters, as well as to assess the sustainable
sulphur and low-sulphur crudes. The dosage was set at 10 ppm for the crude side and 20 ppm for the short residue side, adhering to the same dosages utilised for the ongoing benchmark antifoulant. HP ThermoPro notably decreased the preheat temperature drop on both the crude and short residue sides, compared to prior trial conditions, as shown in Figure 2 . For high-sulphur crude, the drop reduced from 19.1°C to 0.5°C, while for low-sulphur crude, it decreased from 9.2°C to 0.8°C during one year of trials. The data from the field trials, both prior to and during the trials, are illustrated in Figure 2. The HPCL refinery in Mumbai mainly processes waxy crudes and has a distinct crude oil composition when compared to the HPCL refinery in Visakh. To evaluate the performance of HP ThermoPro across a diverse range of crudes, field trials were also carried out at the HPCL refinery in Mumbai. These trials commenced in a fouled preheat exchanger, where the initial preheat temperature was 240°C, in contrast to 260°C in a cleaned preheat exchanger. This setup allowed for the assessment of HP ThermoPro’s cleaning action while maintaining or enhancing the preheat temperatures in the preheat exchanger.
Reduction of preheat exchanger offline cleaning
S. No.
Description
No antifoulant
HP ThermoPro
HP ThermoPro (W)
1 2 3
No. of months
10 16 1.6
18 14 0.8
6 0 0
No. of exchangers cleaned during the period Avg. no. of exchangers cleaned/month
Table 5
Refining India
26
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