Evaluating Naphtha Reforming Catalysts

The ability to test all catalysts simultaneously, under rigorously the same feed and conditions, combined with the proprietary Flowrence® technology used to accurately control all the key process parameters, provides unparalleled precision to discriminate the fine differences between the various catalysts.

Every reforming unit has its own constraints, and the portfolio of catalyst vendors often tries to strike the right balance between performance and the ability to accommodate those constraints. Further than paper estimates, the possibility to simultaneously compare catalysts under various plant conditions and with specific feed properties (e.g. amount of coke precursors, the presence of contaminants such as sulfur, etc.) is thus critical to determine the right catalyst.

The approach presented here for CCR catalysts can be applied to any system that has a noticeable deactivation over the duration of days, or even up to months e.g Semi Regen Reforming Catalysts.

 

Background

Avantium provides comparative catalyst testing for refineries. Our industry-proven Flowrence® 16-reactors pilot plant enables the parallel comparison of multiple catalysts under the exact same conditions. For some years now, Avantium has been helping refineries select the best-reforming catalysts. The tools, methods applied and resulting data quality (precision, accuracy and reproducibility) have been independently verified and accepted by the catalyst vendors.

Axens wanted to evaluate the performance of some naphtha reforming catalysts. Four Axens CCR reforming catalysts were evaluated in a fixed-bed 16 parallel reactor high throughput Flowrence® micro-pilot plant. The performance of the catalysts, defined by activity (temperature required), selectivity (C5+ yield) and stability, was evaluated at fixed product severity. For this test, two octane targets were used but aromatic yield can also be targeted.

Result

The so-called iso-RON operation is achieved by using an automated feedback loop between the GC analysis of the effluent and the reactor’s temperature which is thus continuously adjusted. Key results for catalyst performance with time-on-stream are shown in Figure 1.

Results obtained through iso-RON operation are easy to interpret for fixed-bed units (SR reforming) but also provide invaluable information about catalyst performance for moving-bed CCR units, which would otherwise be too difficult to operate on a lab scale. Lower temperature-required (higher activity) to reach the specific octane means greater flexibility for CCR operation, while a lower temperature slope is typically indicative of a low coke-make.

For a CCR unit, the lower coke-make will provide greater flexibility to increase the product severity (e.g. increased aromatic yield) or to process more demanding feeds like thermal cracked Naphtha. Finally, high catalyst selectivity (C5+ yield) is always desired as long as product severity can be maintained. The stability of the selectivity is typically measured by the length and slope of the stable C5+ yield output before the temperature rises sharply.

Analysis of the coke content (Table 1) of the all the spent catalysts confirms the relationship between coke-make and catalyst stability.

Table 1 – Relative coke content (%wt) on spent samples.

 Catalyst Coke (%wt) for RON = base samples Coke (%wt) for RON = base+ samples
A Ref±0.02 Ref±0.1
B +2.40±0.01 +2.33±0.04
C +5.99±0.07 +4.11±0.22
D +2.71±0.23 +1.99±0.12

Due to differing yield stabilities the selectivities of the catalysts are different relative to one another at different Time on Stream (hr). The appropriate interpretation of this data is dependent upon the coke content in the spent samples. For typical CCR operation, the weight percentage coke on catalyst passing out of the last reactor and entering the regenerator is generally specified to be less than 5%. Since the CCR catalyst’s coke content increases as it passes through the CCR reactors, the average coke for the CCR catalyst, averaged over all the CCR reactors, is then less than 5%.

It is therefore relevant to make the comparison of the relative catalyst yields and activities at appropriate (i.e. coke content <5%) Time on Stream in the iso-RON test analogous to the Time on Stream seen commercially.

These trends are completed with the continuous analysis of the product effluent, which provides vendors and refineries with a complete hydrocarbon breakdown for every point in time. The baseline separation of ethyl-benzene and all xylenes isomers, or the breakdown of the C1 to C6 products for example, are crucial for economic and integration studies.

An example of the precision and discriminative power obtained is illustrated in Figure 2 plots, where key selectivities are plotted against temperature required at a fixed time-on-stream (80 hrs), with clearly non-overlapping confidence intervals.

Thanks to the availability of multiple reactors in the micro-pilot plant, each catalyst system was tested in duplicate for each octane target, in order to provide repeatability and confidence interval on the results.

Flowrence® products specifications

Reactor Section

Easy and quick reactor exchange system. Possibility to use quartz reactors at high pressure.

1 block of 4 reactors

HT = High Temperature max. 800°C nominal, limited to 925°C (<0.5°C reactor to reactor deviation)

4 blocks of 4 reactors

HT  or MT = Medium Temperature max. 525°C (<0.5°C block-to-block deviation)

16 reactors with iRTC

individual Reactor Temperature Control
max. 550°C (<0.5°C reactor-to-reactor)

4 reactors with iRTC

individual Reactor Temperature Control
max. 550°C (<0.5°C reactor-to-reactor)

Temperature Ranges (°C)

100 – 800°C
up 925°C (Option)

50 – 525°C
100 – 800°C
up 925°C (Option)

50 – 550°C

50 – 550°C

Reactor Types

L= Length
OD= Outer Diameter
ID= Inner Diameter
SS= Stainless Steel (< 550⁰C)
Qz= Quartz (< 925⁰C)

L 300 mm 561 mm
OD 3 mm 6 mm
ID SS 2 / 2.6 mm 2 / 3 / 4 / 5 mm
ID Qz 2 mm 2 / 4 mm
300 mm 561 mm 561 mm
3 mm 3 mm 6 mm
2 / 2.6 mm 2 / 2.6 mm 2 / 3 / 4 / 5 mm
2 mm 2 mm 2 / 4 mm
561 mm
3 mm
2 / 2.6 mm
2 mm
561 mm
3 mm
2 / 2.6 mm
2 mm

Maximum Catalyst Bed Length

(isothermal zone tolerance ± 1°C)
Note: isothermal length is dependent on the temperature range

300 / 3 HT 561 / 6 HT
>120 mm @ 450°C >200 mm @ 500°C
>90 mm @ 800°C >150 mm @ 800°C
>140 mm @ 925°C
300 / 3 HT 561 / 3 MT 561 / 6 HT
>120 mm @ 450°C >310 mm @ 450°C >200 mm @ 500°C
>90 mm @ 800°C >150 mm @ 800°C
>140 mm @ 925°C
561 / 3 MT iRTC
250°C ±0.5°C 41cm (4reactors)
350°C±0.5°C 38cm (4reactors)
550°C±0.5°C 28cm (4reactors)
3 reactors at 550°C, 1 reactor 350°C:
550°C=27cm 350°C=41cm ±0.5°C
561 / 3 MT iRTC
250°C ±0.5°C 41cm (4reactors)
350°C±0.5°C 38cm (4reactors)
550°C±0.5°C 28cm (4reactors)
3 reactors at 550°C, 1 reactor 350°C:
550°C=27cm 350°C=41cm ±0.5°C

Catalyst Volume (mL)

(isothermal zone)

0.2 - 0.6 mL 0.4 - 2.0 mL
0.2 - 0.6 mL 0.4 - 1.0 mL 0.4 - 2.0 mL
0.4 - 1.0 mL
0.4 - 1.0 mL

Pressure Ranges (barg)

2 – 80 barg
0.5 – 180 barg (option)

2 – 100 barg
0.5 – 180 barg

2 – 80 barg
0.5 – 180 barg

2 – 20 barg
2 – 50 barg (option)

Reactor Pressure Control

Advanced control RSD ±0.1 barg at reference conditions (gas phase only and 20 barg). For trickle flow Advanced control RSD ±0.5barg.

Standard (±0.5 barg)
Advanced (±0.1 barg) (option)

Standard (±0.5 barg)
Advanced (±0.1 barg) (option)

Advanced (±0.1 barg)

Advanced (±0.1 barg)

Gas Feed Lines

(#Gas Feeds)

Up to 6 + Diluent gas

He, Ar, N2, H2, CH4, CO2, C2H4, C2H6, O2/Inert (≤5%), CO, Other gases

Up to 7 + Diluent gas

He, Ar, N2, H2, CH4, CO2, C2H4, C2H6, O2/Inert (≤5%), CO, Other gases

Up to 7 + Diluent gas

He, Ar, N2, H2, CH4, CO2, C2H4, C2H6, O2/Inert (≤5%), CO, Other gases

Up to 6 + Diluent gas

He, Ar, N2, H2, CH4, CO2, C2H4, C2H6, O2/Inert (≤5%), CO, Other gases

Online Analysis

Full integration GC, MS , GC/MS with data visualisation (option)

Full integration GC, MS , GC/MS with data visualisation

Full integration GC, MS , GC/MS with data visualisation

Full integration GC, MS , GC/MS with data visualisation

Liquid Feed

 Split feeding 8 + 8 reators (option)

Pump-Coriolis dosing system
(ambient, cooled)

Pump-Coriolis dosing system
(ambient, cooled, heated 80°C)

Pump-Coriolis dosing system
(ambient, cooled, heated 80°C)

Pump-Coriolis dosing system
(ambient, cooled, heated 80°C)

Liquid Distribution

Microfluidic Distribution
(4-channel glass-chip)

Microfluidics Distribution
(4x4-channel glass-chip)
(16-channel glass-chip)
Active Liquid Distribution (option)
(with automatic isolation valves)

Active Liquid Distribution
(with automatic isolation valves)

Microfluidic Distribution
(4-channel glass-chip)

Liquid Sampling

(G/L Separation)

Parallel liquid sampling (4 x 20ml vials) with sequential on-line gas phase sampling (option)

Automated liquid sampling (4 rows x 16 vials x 8ml) with sequential on-line gas phase sampling (option)

Automated liquid sampling (4 rows x 16 vials x 8ml) with sequential on-line gas phase sampling (option)

Parallel liquid sampling (4 x 20ml vials) with sequential on-line gas phase sampling (option)

Reactors Effluent Handling

(Off-line Analysis Connection)

Full heated circuit up to 180°C with sequential on-line full gas phase sampling (option)

Full heated circuit up to 200°C with sequential on-line full gas phase sampling

Full heated circuit up to 200°C with sequential on-line full gas phase sampling

Full heated circuit up to 200°C with sequential on-line full gas phase sampling

Offline Analysis

Integrated Workflow: SimDist, total S/N, liquid density, balance, label printer, barcode (option)

Integrated Workflow: SimDist, total S/N, liquid density, balance, label printer, barcode

Integrated Workflow: SimDist, total S/N, liquid density, balance, label printer, barcode

Integrated Workflow: SimDist, total S/N, liquid density, balance, label printer, barcode

Waste Handling

Ambient temperature
Heated wax trapping (option)

Ambient temperature / Cooled containers / Heated compartment (wax trapping, heavies)

Ambient temperature / Cooled containers / Heated compartment (wax trapping, heavies)

Ambient temperature / Cooled containers / Heated compartment (wax trapping, heavies)

Safety

Gas sensors and control box (CO, LEL, VOC)

Gas sensors and control box (CO, LEL, VOC)

Gas sensors and control box (CO, LEL, VOC)

Gas sensors and control box (CO, LEL, VOC)

Flowrence® Software

Flowrence® recipe builder, control & database builder

Flowrence® recipe builder, control & database builder

Flowrence® recipe builder, control & database builder

Flowrence® recipe builder, control & database builder

Microfluidics modular gas distribution

Unrivalled accuracy in gas distribution with patented glass-chips for 4 and 16 reactors, with a guaranteed flow distribution of 0.5% RSD. Quick exchange of glass-chips for different operating conditions. Flexibility to cover a wide range of applications.

TinyPressure glass-chip holder with integrated pressure measurement

Compact modular design for gas and liquid distribution. No high-temperature pressure sensors required. Quick exchange of the microfluidic glass-chips, without the need for time-consuming leak testing.

Tube-in-tube reactor technology with effluent dilution

Unique tube-in-tube design with easy and rapid exchange of the reactor tubes (within minutes!). No need for any connections. Use of inert diluent gas (outside of reactor) to maintain the pressure prevents dead volumes and back flow. Possibility to use quartz reactors at high pressure applications.

Automated liquid sampling system

Programmable, fully automated liquid product sampling robot for 24/7 hands-off operation. Robot equipped with a compact manifold aiming at depressurizing the effluent immediately after each reactor to atmospheric pressure. Eliminates the use of high pressure valves.

Reactor Pressure Control (RPC)

The most accurate and stable pressure regulator for a 16-parallel reactors with just ±0.1bar RSD. The RPC uses microfluidics technology to regulate the pressure of each reactor, maintaining equal distribution of the inlet flow over the 16 reactors.

Auto-calibrating liquid feed distribution, measurement, and control

Distribution of difficult feedstocks e.g., VGO, HVGO, DAO. Liquid distribution 0.2% RSD, making it the most accurate liquid distribution device on the market. Option to selectively isolate each reactor.

Single-Pellet-String-Reactors (SPSR)

No dead-zones, no bed packing & distribution effects. The catalyst packing is straightforward and does not require special procedures. A single string of catalyst particles is loaded in the reactors avoiding maldistribution, eliminating channeling and incomplete wetting.

EasyLoad®

Unique reactor closing system with no connections. Rapid reactor replacement minimizing delays, improving uptime and reliability. Stable evaporation by liquid injection into reactor.

Contact us

We are here to help you

 

 

 

 

 

 

 

 

Avantium Headquarters

+31 (0)20 586 8080

Zekeringstraat 29
1014 BV Amsterdam
The Netherlands

Contact us