328
326
SRGO feed
SRGO + 15% LCO
SRGO + 30% LCO
324
SRGO + 15% LCO
SRGO + 45% LCO
322
320
318
316
314
312
310
50
100
150
200
250
300
350
400
450
500
Elapsed run time , h
Figure 2 Temperature program followed during the test
total hydrogen circulation rate. Finally, a higher hydrotreat- ing temperature requirement accelerates catalyst deactiva- tion due to a faster coking rate. These requirements are particularly important for exist- ing hydrotreaters seeking the opportunity to process more LCO, as these old hydrotreating units are often limited in reactor volume, pressure rating, and hydrogen compression capacity. For this, it is important to evaluate the implications of introducing more LCO in diesel hydrotreating units and effectively evaluate the impact on hydrodesulphurisation (HDS) conversion and hydrogen consumption. Catalyst loading schemes In demonstrating how independent catalyst testing helped a European refiner confirm their existing hydrotreating unit’s ability to cope with different LCO blending targets, it was crucial to focus on hydrogen consumption, cycle length, and aromatics content. Moreover, different catalyst
loading schemes were evaluated to determine which one was the best fit for the existing equipment. The catalyst evaluation was performed at Avantium labo- ratories in Amsterdam using a dedicated Refinery Catalyst Testing (RCT) high-throughput unit with 16 parallel reac- tors employing Avantium’s proprietary technology, which will be discussed and described further in Figure 3 . The test program consisted of a run of about 20 days (excluding activation) where four ULSD catalyst configu - rations (CoMo, NiMo, and stacked beds of NiMo + CoMo) loaded in duplicate reactors were exposed to three different feed blends (SRGO + LCO) with three levels of LCO: 15%, 30%, and 45%. The operating temperature was adjusted to reach a product sulphur of around 8 ppm. The complete set of results obtained from the test was very consistent, showing the expected correlation among different measurements, such as hydrogen consumption, gas make, liquid product density, and product aromat-
ics content. These results, combined with an exceptional reactor-to-reactor repeatability, confirmed the experimental test’s validity, rel - evance, and accuracy. Experimental The test program aimed to determine the effect on catalyst performance when process- ing blended feeds of SRGO + LCO in diesel hydrotreating units at start-of-run conditions (SOR). Eight catalytic systems of CoMo, NiMo, and stacked beds of NiMo + CoMo were exposed to the different blends of SRGO + LCO during a period of 20 days (excluding activation). Different feeds were introduced into the catalysts by changing the amount of LCO blended with the SRGO, while the oper- ating temperature was adjusted at each con- dition to reach a product sulphur of 8 ppmw – initial temperature estimates were provided by the customer. The minimum time of stabilisation used after
Properties of the feed blends used during the test
Feed
100% SRGO 85% SRGO/ 70% SRGO/ 55% SRGO/ 15% LCO 30% LCO 45% LCO
Sulphur, ppmw Nitrogen, ppmw
5035
4778
4463
4168
77
227
361
482
Density at 15˚C, g/ml Aromatic, Mono, wt% Aromatic, Di, wt% Aromatic, Tri, wt% Aromatic, Total, wt%
0.8422
0.8574
0.8682
0.8878
16.3
17.4 14.1
18.5 16.2
19.6 20.6
7.5 0.5
2.9
4.9
7.0
24.3
34.4
39.6
47.2
SIMDIST, wt%
Boiling temperature, °C
IBP
111 158 177 223 265 297 334 351 393
111 168 188 234 274 310 354 373 429
111 167 189 233 273 311 358 380 435
111 175 197 243 282 320 373 396 457
5
10 30 50 70 90 95
FBP
Table 1
44
Catalysis 2023
www.digitalrefining.com
Powered by FlippingBook