Since 1930, chemical manufacturing has been carried out at our Cassel site on Teesside in the North East of England. The site is home to 12 plants, employing 240 people, producing five products and is the largest MMA production site in Europe.

The next two years will see some significant upgrades at Cassel, demonstrating Mitsubishi Chemical’s commitment to the long-term future of the biggest MMA production plant in Europe and one of the group’s longest serving assets.

These upgrades will see the installation of a heat recovery plant to reduce the site’s energy consumption/carbon emissions; and the replacement and upgrade of the site’s 30-year old SAR (Sulphuric Acid Recovery) Furnace and the SAR Converters, both of which are nearing the end of their designed service life.

Energy generation with new heat recovery plant

The creation of a new heat recovery plant at Cassel is part of a wider investment project that also includes the replacement of the SAR Blower and a necessary upgrade of the site’s electrical infrastructure. Once complete, the new steam turbine generator will meet the site’s full power demands, utilising waste process steam alongside gas-fired boilers which generate any additional steam required for the turbine.

Pictured: a model of the new steam turbine generator.

Alongside the new heat recovery plant, the replacement of the existing steam-driven SAR blower with an electrically powered unit will deliver 10% more processing capacity, freeing up additional process steam to supply the steam turbine and removing a current SAR plant bottleneck created by the existing blower.

The new, internally generated electricity from the heat recovery plant will immediately reduce the total energy usage and carbon emissions of the site, making an important contribution to MCC’s KAITEKI targets. Longer-term, these improvements in energy efficiency will help to protect the site from expected electricity price increases, while the simultaneous replacement of ageing electrical infrastructure will help to secure the ongoing reliability of the Cassel site’s current technology best practice.

SAR Furnace replacement

This project will replace the 30-year-old furnace and associated ductwork and burners with a larger horizontal furnace in the same location as the existing furnace, and an upgraded Burner Management System.

When the Cassel Project Team were considering the options for the replacement furnace, they wanted to build in several performance improvements. The following have been incorporated into the design:

– The furnace volume has been increased by 30% which allows a longer residence time

– This allows the furnace to operate at reduced temperatures, minimising key emissions such as NOX

– This increased size also allows for a reduction in natural gas usage which, again, reduces air and water emissions

– The new furnace design has allowed for better positioning of the burners, which improves mixing and therefore efficiency

– The new furnace will be fully brick lined, which will allow for easier and quicker repair through its life

The initial project feasibility study also looked at radically changing its configuration by relocating it or replacing the horizontal furnace with a vertical unit. Whilst the experience within the MCC/LI group has shown that there are pros and cons for horizontal vs vertical furnaces, switching from a horizontal to a non-standard, unproven vertical design, limited by the space constraints, was not recommended by the technology provider.

Primarily because of the restricted space available, a replacement horizontal furnace in the existing location was considered the only feasible option, allowing sensible design improvements to meet current technology best practice.

Having approved the projects in principle and the investments required, detailed designs for the furnace and converter replacement as part of the 2021 outage are currently underway.  Manufacture of the components will start later this year and on-site fabrication is scheduled to commence in March 2021 with the replacement units coming into operation by the end of 2021.

SAR Converter replacement

The SAR Converter at Cassel is a 30 year old Chemetics Proprietary Design. As with the SAR furnace, several options and performance improvements were considered by the Cassel Projects Team.

Pictured: the existing SAR Converter

The new vessel is 10% larger to incorporate future site upgrades and design enhancements which, for example, allow for safer and easier access during outages to refresh the internal catalyst.

Having approved the projects in principle and the investments required, detailed designs for the furnace and converter replacement as part of the 2021 outage are currently underway. Manufacture of the components will start later this year and onsite fabrication is scheduled to commence in March 2021 with the replacement units coming into operation, again, by the end of 2021.