The final step of the malting process is to kiln the germinated grain to stop it growing and prepare it for use in the distilling and brewing processes. Kilns use burners to heat air that is then blown from below, up through a bed of green malt. Any of the hot air that has already passed through the malt that can be recaptured can result in a saving of burner fuel.
The three original kilns at Tweed Valley Maltings are still operating, demonstrating the resilience of the engineering in their construction. Square, brick built kilns take batches, their energy efficiency had been eroded over time as heat was escaping through their ceilings and the capture of heat from the air off the kiln was being hindered by damaged heat exchangers in the recirculation ductwork.
While the opportunity from addressing these issues was clear, to extend the life of these assets, the kilns operate continually and Simpsons Malt were very keen to maximise production as much as possible throughout the upgrade project.
The Kiln Upgrade scope was broken into three areas focusing on the ceiling repair, the ductwork upgrade and the replacement of the glass tube heat exchangers.
The work was approached such that only one kiln would be out of operation at any one time. The ceiling replacement involved modular stainless steel panels being installed and welded together to prevent any leakage of hot air or moisture from the kilns themselves. The joints between the stainless and the brickwork were also carefully sealed and insulation installed. Working adjacent to operating kilns made for a cosy environment and our team of engineers monitored their water intake carefully in the hot conditions!
The external ductwork could be addressed independently outside the building with careful demolition followed by rapid installation of the bespoke designed stainless ductwork sections and insulating panels.
The heat exchangers, comprising a large number of thin walled glass tubes, were on a long lead time and were ordered well ahead of when the project would be ready to install them. Cranage into place ensured no breakages and the ductwork at height created the optimal air flows for the escaping heat to be captured and transferred to the ambient air on the intake side of the kiln fans.
The Kiln Upgrade project was successfully implemented, extending the life of these key Simpsons Malt assets. The work was coordinated well around operational requirements and an unerring focus on safety ensured no incidents occurred.
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Working with Edwards to repair the three Kilns ensures we have a robust infrastructure that will work efficiently for many years to come.
Pat Richards, Chief Engineer for Simpsons Malt
