Nov-2020

Arkema develops new digital features for the sulphiding of hydroprocessing catalysts (ERTC)

In 2020, Arkema successfully tested and implemented a digital environment that both eases and strengthens data communication with the refinery during the sulphiding of hydroprocessing catalysts. This digital tool is set to become the new standard for conducting modern catalyst sulphiding in years to come.

Francis Humblot
ARKEMA

Article Summary

Catalyst sulphiding with DMDS and Carelflex® service, a standard solution
Hydrotreating (HDT) catalysts must be converted to their sulphide form to obtain the desired activity. This is traditionally carried out during unit start-up by injecting a sulphiding agent into the feedstock, the sulphiding agent then being converted to hydrogen sulphide (H2S), which reacts immediately with the catalyst.

More than 15 years ago, Arkema introduced the ‘efficient sulphur’ concept, where all sulphur present in the sulphiding agent — dimethyl disulphide (DMDS) having 68 wt% sulphur — is efficiently converted to H2S on the hydrotreating catalyst under standard sulphiding conditions. Indeed, coking phenomena can interfere with catalyst activation, as they create a physical barrier to active sites and reduce catalyst activity. Hence, the choice of sulphiding agent structure plays a key role in catalyst life cycle. Over the years, DMDS has shown its superior performance compared to other sulphur chemicals.

For ease of use, Arkema also developed a better smelling DMDS called DMDS Evolution® E2. Combined with the company’s Carelflex® service, which offers high-quality equipment and a dedicated, flexible team to handle and inject the DMDS, this provides refineries with a reliable, cost-effective, and global solution for the start-up of any hydroprocessing unit such as gasoil hydrotreaters, vacuum gasoil hydrotreaters (pretreat FCC), or hydrocrackers.

A step further to improve start-up procedure: an in-line H2S analyser
In 2013, in keeping with its policy of innovation, Arkema added an extra service to its current Carelflex service: in-line H2S analysers to measure the H2S content of the recycle hydrogen, which is a key parameter in properly conducting catalyst activation (See previous articles in ERTC newspapers in 2017 & 2018). This service has met with great success, firstly because it addresses a safety concern: the risk of a refinery operator being  exposed to a toxic gas, H2S, while they use reactive tubes to manually measure its concentration.

In addition to the HSE improvement, Arkema’s H2S analysers offer continuous H2S measurement, which allows the refinery to anticipate DMDS flow rate and reactor temperature changes, saving time and significant volumes of DMDS. Moreover, the refinery is able to fine-tune the DMDS flow rate to stabilise H2S concentration at around 1% after H2S breakthrough, to mitigate the risk of recycle hydrogen compressor choking and to minimise SOx emissions related to hydrogen purge.

More than IIoT, a full digitalisation project for Carelflex service
Thanks to its extensive experience in hydroprocessing catalyst sulphiding operations, Arkema quickly identified the value of a digital sulphiding service to refineries. Until recently, the Carelflex operator shared DMDS data (flow rate and cumulated amount injected) and H2S concentration data with the refinery on a regular basis and on-demand. However, thanks to the latest advances in data management and communication, it is now possible to collect these data, format them, and make them available to the refinery on a real-time basis. The challenge was to establish a robust and reliable system, which is private, secured, and compatible with the portable equipment used in different countries.

In 2020, despite unsettled circumstances, Arkema managed to test its digital Carelflex environment and perform the first sulphiding operation with a digital DMDS injection skid and H2S analysers, together with an ATEX tablet used by Carelflex operators and the customer to access all collected and formatted data (see Figures 2 and 3).

Each test procedure has provided the opportunity to collect constructive feedback from end users (both refinery and Carelflex teams) and to continue to improve the digital system so it can be quickly paired with the existing injection equipment. The security of the system complies with the highest standards such as double identification. Thanks to its ease of use, Arkema believes  it will  rapidly become the new standard for conducting modern catalyst sulphiding.

This short article originally appeared in the 2020 ERTC Newspaper, produced by PTQ / DigitalRefining.

You can view the digital issue here - https://online.flippingbook.com/view/1029582