Fuels and bottoms upgrading Lastly, Figure 8 was generated for a historical understand- ing of transportation fuels and bottoms upgrading over two decades. As expected from the previously discussed points, namely the drop in REO content and the increase in phos- phorous content on Ecat, the gasoline yield has decreased significantly in all regions. Over the 21-year history, the global gasoline yield has decreased from 48% to 45%, indi- cating a major shift in FCC operating strategy. The decrease is driven by the lower gasoline need from refined oil and the higher need for light olefins for chemi - cals. Other global drivers are contributing to this trend, such as renewable fuel sources, improved fuel efficiency, and increase in the adoption of light-duty electric vehicles. As seen with the prior LPG figures, the spread in the data has increased over the years. Back in 2002, most gasoline selectivities were between 45-51 wt% (Δ6 wt%), and in 2022 that spread is now 40-49 wt% (Δ9 wt%). The Ecat LCO-to-bottoms (LCO/BOT) ratio is a measure of the bottoms upgrading selectivity of the catalyst to LCO. Since the start of the pandemic, the LCO/BOT ratio has increased in all regions except EMEA. This also corresponds to when IMO 2020 went into effect, limiting the amount of sulphur in bunker fuel, which is an outlet for FCC bottoms product, for marine vessels without SOx capture technol- ogy. The improvement in LCO/BOT correlates well with the decrease in Z/M for the previously shown regions. Conclusions In summary, two decades of FCC catalyst trends are cov- ered, providing insights into refiner and consumer behav - iours, with the focus on recent trends through Covid-19 and post economic recovery. The FCC, which historically has been the gasoline machine of the refinery, shows a drastic gasoline selectivity decline over the two-decade history in favour of other more valuable products like LPG and LCO, the latter being a diesel precursor. This trend is expected to continue, given recent regulations, such as the Inflation Reduction Act in the US and various policies in the European Union, which will drive the long-term adoption of electric vehicles and more stringent fuel economy stan- dards on internal combustion engine vehicles. During the pandemic, catalyst activity decreased as units targeted the production of LCO, a diesel precursor, over gasoline. In addition to diesel, during the pandemic, demand for chemical precursors including propylene (used in the production of medical face masks and other medi- cally necessary equipment and supplies) was stronger than gasoline. Refiners used olefins additives to selectively crack gasoline range molecules into LPG. An increase in olefins additive usage through the phospho - rous chemical marker is seen. With the economic recovery of 2022, catalyst activity is increasing again. However, instead of olefins additives decreasing, it is increasing or holding steady in all markets. This shows a larger global trend toward making LPG olefins during the economic recovery. This trend of higher LPG olefin production from the FCC is expected to continue with recent investments in petro- chemical integration, particularly in the Middle East and
to unit bottlenecks and niche regional economies), while those in the 90th percentile show a significant increase over the years of ~4 wt%! In addition to the LPG olefin yields, we also looked at the selectivity within the LPG olefins stream and, in particu - lar, the propylene-to-butylenes ratio. This ratio is a factor of many variables, including catalyst activity, REO, olefins additive, and Z/M ratio. For olefins additives, the most widely used variant is ZSM-5 based, which significantly increases the propylene-to-butylene ratio. Based on the increase of phosphorous, which indicates higher ZSM-5 usage, we would expect higher propylene-to-butylene ratios. The global ratio increased in 2020 during the pandemic with the rise in phosphorus, but in the two years following it decreased despite global phosphorous levels staying the same (indicating a similar level of ZSM-5 usage). This implies that catalyst selectivity, aside from additive selectivity, is driving towards higher butylenes. This is in line with recent technology advancements in the maximum butylenes segment, with refiners adapting the latest tech - nologies to drive profitability from butylenes. This is fur - ther supported by the trends within the regions, with Asia and EMEA showing higher propylene-to-butylenes ratios. The Americas, with the largest alkylation capacity globally, has the lowest ratio and has historically been the greatest adopter of the max butylenes catalyst technologies. Similar to the total LPG olefins graph, we see the spread of data widening over time with units geared towards maximising propylene (high C 3 =/C 4 = ratio) and others geared towards the other extreme of maximising C 4 =s (low C 3 =/C 4 = ratio).
35 39 37 41 43 45 47 49 51 53
Global
Americas
Asia
EMEA
0.5 0.9 0.7 1.1 1.3 1.7 1.5 1.9 2.1
Global
Americas
Asia
EMEA
Figure 8 Global transportation fuels and bottoms upgrading trends; gasoline yield (top) and LCO-to- bottoms ratio (bottom)
40
Catalysis 2023
www.digitalrefining.com
Powered by FlippingBook