Bespoke Filter Solution for Catalyst protection on Diesel Hydrotreating Unit

Product

Nylon HFC Supapleat

Client

Global Petrochemical Company

Application

Hydrotreating

Location

Malaysia

Value Added

Improved on-stream lifetime

Sector

Oil & Gas

Background

Hydrotreating or hydrodesulphurisation is one of the most important steps in the production of Euro 5 diesel. Although the current drive is towards electrification there is still and will remain for the foreseeable future, a strong demand for diesel fuel.

The combination of ever increasingly tighter regulation on NOX and SOX emissions coupled with the reduced availability of low sulphur crude oil means the process of hydrotreating is increasingly critical. Efficient hydrotreating also increases the stability and decreases the volatility of the diesel resulting in longer storage life.

The Process

The process begins with the on-line mixing of various straight run and heavy diesels prior to the fluid passing through a filter to remove unwanted particulate.

This prefiltration stage is critical in ensuring that the catalyst bed (typically Cobalt- Molybdenum) is adequately protected. Particulate contamination onto the bed can severely impact process flows and efficiency, which would result in an increase in OPEX.

The problem

The diesel process stream typically operated at 120 °C (248 °F) and with peak temperatures up to 170 °C (338 °C). There were a combination of problems reported by the process engineers around the service life of the original filters.

The Operators reported that the filters (utilising glass microfibre media) were suffering from short life (having to change every shift to a maximum of 3 days)
Filters were becoming stuck in the tube sheets. This resulted in not only the expense of significant additional consumable filter costs but also the extended maintenance time required for change out.

The diesel hydrotreating is a continuous process and housings are installed as 1 duty and 2 standby. The process was therefore not interrupted but the implications of excessive filter consumable costs and potential filter bypass due to filter damage had to be addressed.

The solution

Our technical teams worked closely with the company's process engineers to establish a more suitable filtration media in terms of material compatibility and efficiency rating.

A number of prototype filters of varying micron ratings were manufactured for proving trials both in terms of performance and fit. The initial three trial sets were designed, manufactured, and supplied to the customer's site in Malaysia within 4 weeks.

CASE STUDY Test fitting of prototype filters by process engineers

The filters were also supplied as a single piece construction (seen on the left in the photo below), eliminating the multi weld which was another potential source of failure in this aggressive environment.

Asset 12@3x

Asset 11@3x

The results

The new filters based on pleated Nylon media were successfully tested at production capacity while showing no signs of material degradation while in service. The filtrate quality was monitored during the process and qualified as being in the specification.
Since installation, the new filters have demonstrated a significant increase in on-stream life.

The hydrotreating process is run at different capacity levels depending on demand. The table below shows the increase in on stream life at different process capacities.

table

Key takeaways

Compatibility of filtration materials is key in refinery applications
Working with a supplier that can develop and produce bespoke filters is priceless when needing to quickly problem solve

Bespoke Filter for Catalyst protection on Hydrotreating Unit