Zeopore enables breakthrough in hydrocracking by leveraging zeolite mesopore quality
Targeting higher fractions of middle distillates in hydrocracking installations is highly desired but challenging, especially when aiming to maintain process activity and energy consumption. Over recent years, Zeopore has introduced innovative technologies to increase mesoporosity and retain intrinsic zeolitic properties. Now, after having completed a high-throughput testing campaign at a major refining company, Zeopore demonstrates excellent hydrocracking performance in comparison to un-mesoporised zeolite catalysts. In addition, Zeopore is able to eliminate the typical corresponding decline in process efficiency.
Kurt Du Mong, CEO of Zeopore: "Next to FCC and dewaxing refining applications, our mesoporised zeolites have now also shown substantial value in hydrocracking, yielding benefits of 15 mln USD per refinery. Furthermore, we have gained unique insights in performance drivers, which we can reach starting from low quality or intermediate faujasites, hereby enabling opening up global supply chains toward low-cost and high-quality hydrocracking catalysts."
Hydrocracking as main value contributing refinery operation
As the key value generator in many established refineries, increasing the output towards desired fractions in a hydrocracker is a major commercial and efficiency driving force. Hydrocracking (HDC) is a key refining operation whereby mesoporised zeolite catalysts are known to deliver more middle distillates, but so far at the expense of decreased activity and thus higher energy need.
A reason for this is the lacking understanding of the key zeolitic descriptors that bring optimal hydrocracking performance for the case of mesoporised zeolites. This may be due to the limited access of industrial supply to high quality and, moreover, tunable mesoporous zeolites, such as mesoporous faujasites for HDC.
High throughput testing unlocks higher selectivity even at increased activity
Fueled by Zeopore’s unique capability of extensive zeolite tuning, a high-throughput testing campaign at a major refining company was launched to evaluate several different mesoporous zeolites under various reaction conditions. Concretely, Zeopore has invested in catalytic testing using NiW mesoporous USY-based catalysts with a refiner's high-throughput testing units on an industrial feed. The aim was to attain excellent HDC performance in comparison to untreated (parent) HDC zeolites, but also to gain in-depth understanding of the influential parameters driving HDC activity and selectivity.
Figure 1: Evolution of the middle distillates yield as a function of conversion. Inset: conversion as a function of reactor temperature.
The results demonstrate strongly enhanced selectivities, but equally an increased activity, as evidenced by lower reaction temperatures at equal conversions. This is unique, as it allows to significantly lift the performance bar as compared to other levers like zeolite content, process conditions, etc.
A remarkable fact is that two zeolite catalysts, despite very similar general meso-zeolitic properties, exhibit very different performance characteristics in hydrocracking, as shown in Table 1. Both zeolite catalysts feature a roughly doubled mesopore volume, and a large preserved microporosity, total surface area, and acidity. The different performance of the materials illustrate clearly that common descriptors fail.
|
Aspect / as compared to standard HDC zeolite (base) |
Meso-zeolite A |
Meso-zeolite B |
|
Micropore volume / % |
80 |
85 |
|
Mesopore volume / % |
191 |
193 |
|
Total surface area / % |
118 |
120 |
|
Overall acidity / % |
89 |
82 |
|
|
|
|
|
|
MEDIOCRE PERFORMANCE |
HIGH PERFORMANCE |
|
T / °C |
+3 |
-2.5 |
|
Gas / wt% |
-0.3 |
-0.7 |
|
Naphtha / wt% |
-1.1 |
-3.0 |
|
Middle Distillates / wt% |
+1.5 |
+3.8 |
|
|
|
|
Table 1: Properties and catalytic HDC performance of two similar mesoporous USY zeolites as compared to a standard USY base case.
Mesopore quantity and quality
Classic descriptors of USY activity in hydrocracking play an important role in predicting and designing the optimal hydrocracking performance. These descriptions have focused traditionally on the molar SiO2/Al2O3 ratio (SAR), and the total acidity, relatively crystallinity and unit cell size. Secondary porosity, as measured using N2 or Ar sorption or Hg intrusion, has been accepted more recently as additional relevant influencer.
Zeopore has now learnt that the classic descriptors only function well for a similar group of USYs: those obtained using the standard methods to prepare USYs for HDC starting from NaY zeolites: using ion exchange, framework dealumination through steam, and bulk dealumination through acid.
However, when Zeopore’s targeted and optimized mesoporization technologies are applied, the tunability of the resulting materials is much higher, leading to fundamentally different materials in overall porosity, bulk and framework composition, and acidity. It is therefore not surprising that classic descriptors of mesoporous zeolites do not yield a clear picture when related to the middle distillates yields (Figure 2, top).
By combining our know-how on the tuning of mesoporous zeolites with the results of the high-through put HDC testing, Zeopore hereby introduces a new generation of (proprietary) catalytic descriptors for middle distillates-selective HDC. This selectivity descriptor combines aspects of mesopore quantity with mesopore quality, and yields a much better picture (Figure 2, bottom).
Figure 2: (top) Classic descriptors of mesoporous zeolites do not yield a clear picture when related to the middle distillates yields. (bottom) A new generation of (proprietary) catalytic descriptors for middle distillates-selective HDC - mastered by Zeopore - yields a much better picture.
Similarly, Zeopore has learnt that also established activity descriptors, such as total acidity and SAR descriptors fail to give a full picture. Indeed, samples with suboptimal mesoporosity can display a lower Bronsted acidity as compared to the parent zeolite, which also results into a lower activity. However, remarkably, the optimal mesoporous samples, display a much different trend: at similar acidity, a temperature of 60% conversion of an impressive 4°C lower is attained. Again, using the right activity descriptor enables to get a better correlation among samples which have been synthesized using distinct manufacturing methods.
Danny Verboekend, CTO of Zeopore: “The identification of these advanced descriptors is key to unlock the full potential of mesoporous faujasites in hydrocracking, and in turn, to streamline the design and manufacture of mesoporous USY-based catalysts. In these efforts, we are excited to work with strategic partners to deliver maximum value to refiners.”
Painting the overall landscape
Our unique descriptors of the activity and selectivity in hydrocracking enable us to further develop our technology in a focused way in order to compare with today's state-of-the-art hydrocracking catalysts even more favorably.
By combining both activity and selectivity descriptor, an intuitive visualization of potential HDC performance is obtained (Figure 3). Herein, the best performing materials are positioned on the top right corner. State-of-the-art academic and patented technologies display a movement rightwards, yet also the common pitfall of mesoporous zeolites: a clear activity loss. Instead, by using Zeopore’s materials, the rightward movement is not only far more pronounced, it is also combined with an unaffected activity level.
Figure 3: Overview of conventional (orange), state-of-the-art mesoporised (red) and Zeopore mesoporized USY zeolites (blue) as a function of activity and selectivity descriptor.
Obviously, the benefits of the improved performance are clear, yielding an impressive 0.5 USD per barrel and 15 mln USD per cycle extra for an average cracker, making an attractive business case for any refiner. Moreover, secondary benefits like reduced lights, lowered hydrogen consumption, and a lower reactor temperature are becoming increasingly valuable, as they positively impact the environmental footprint of the unit.
Fast track for mesoporous faujasites
The awareness of advanced descriptors to identify superior (mesoporous) faujasites, enables to speed up further catalyst development by using them as compass for further improvements. For example, based on the use of advanced descriptors, Zeopore has already been able to prepare several distinct families of faujasites. Some are expected to outperform those tested today, whereas others offer potential from a cost perspective.
Currently, Zeopore is setting up its own industrial pilot unit. Kurt Du Mong: "This allows us to further optimize our unique mesoporization process and deliver ton-scale testing volumes of mesoporized zeolites. It is a truly exciting step in the current scale-up stage in Zeopore’s growth path, for which we receive governmental funding to further grow a zeolite catalysis knowledge and commercial stronghold. This major effort underlines the trust our investors and partners have in us and our commitment towards prospects and customers."
Zeopore is currently exploring options to further capitalize on these findings, by furthering the in-depth understanding of mesoporous USY zeolites, as well as extrapolating to different types of (sustainable) feedstocks and lighter product ranges.
Opening up global supply chains
The main achievement is that Zeopore's tunable meso-zeolites demonstrate substantial middle distillate selectivity benefits at an increased activity in the key hydrocracking operation in refining. At the same time, the high-throughput testing campaign enabled Zeopore to gain more in-depth insights into key zeolite descriptors, which are essential in focusing further on maximizing HDC performance.
Kurt Du Mong: "In our latest development tracks, we have demonstrated our capability to arrive at the defined optimal meso-zeolitic properties, not just by mesoporizing typical (high quality but expensive) hydrocracking zeolites, but already starting from (cheaper) intermediate and/or low quality faujasites. As a result, we strongly reduce the cost impact of the treated material, and also open up global supply chains for our customers towards low-cost and high-quality hydrocracking zeolites, strongly improving their security of supply position."
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