Project VELG – Hot gas bag filtration system for bio-energy malt whisky distillery

CONSULTANT’S REPORT

Late in 2020, we won a project which we had first quoted in 2016.  The project involved providing a cleanPULSE bag filter, ducting, cleanSPARK box, 75kW fan and a spark detection and extinguishing system for a bio energy plant at a distillery situated in the stunning Speyside region in the Scottish Highlands. 

In visitscotland.com's words: 

‘Speyside is whisky heaven! By far the largest (by number of distilleries) and arguably the most famous of Scotland’s whisky regions, this breath-taking area sits in a fertile valley of rivers and secluded glens and is home to over half of Scotland’s distilleries’. 

As well as designing and supplying, our scope extended to Installation, including insulation and cladding of all the ducting from the connection to the existing economiser outlet through to the stack inlet. 

An initial site survey had been conducted back in 2016 but knowing the space for a new filter was tight and difficult to access an additional site visit was required with a draughtsman to plan the full layout and ducting route.  Access to site was initially delayed several weeks due to COVID but was subsequently conducted as soon as the UK government restrictions were lifted. Spare space was minimal, but a layout was agreed that allowed sufficient access for future maintenance and sufficient ducting linear length for the Grecon system.  Sam had been recruited by FDL in the middle of the COVID pandemic and his home location was in Aberdeen. This meant his travel to site was a mere 2-hour drive North to the distillery, and so he was best placed to design this project as he could visit site within a day to check on details, dimensions etc. 

Supply Highlights

• Design, supply, installation, commissioning
• Insulated and clad high temperature cleanPULSE filter system
• 10kW of trace heating applied to the cleanPULSE hopper 
• Insulated and clad cleanSPARK box
• Insulated and clad ducting from clients Economiser through to existing stack  
• Grecon spark detection system
• Heated and insulated water pipework to spark suppression 
• 75kW centrifugal fan 
• Hopper screw conveyor
• Chute from screw conveyor to clients existing rotary valve

Supply Detail

• Design, supply, installation, commissioning
• Filter bag diameter: 127mm
• Filter bag length: 5000mm
• Filter arrangement: 2 sections of 14 rows of 12 filter bags
• Total filter media: 686m²
• Filtration gas volume: 35,720Am³/hr
• Matrix system pulse controller with 4-20ma output 
• Integrated pulse valves in 
• Inlet gas distribution baffles 
• Hopper trace heating: 10kW
• Filter and hopper insulated in 75mm thick Rockwool
• Insulated access doors to filter bags and hopper
• Filter and hopper clad with 0.7mm Goosewing Grey profiled cladding
• Galvanized filter support frame with heat isolation pads on each leg
• Galvanized access ladder with intermediate platform
• Hopper trough conveyor: purposely limited to 1t/hr throughput
• Induced draft fan: 75kW motor 
• 75mm Rockwool insulation and 0.9mm stucco aluminium cladding on fan 
• Ducting design in S275JR mild Steel - 4mm thick duct, 6mm thick bolted flanges. 
• 2 x internally profiled bolted duct inspection doors 
• Spark detection ports, spark arrest ports in duct
• A total of 4, 1” bsp ports for gas inlet and outlet temperature instruments
• Accommodate clients existing dust monitoring probe. 
• Ducting finished in Firwoods 75 high temperature paint 
• Ducting and CleanSPARK insulated with 75mm rockwool
• Ducting and CleanSPARK clad with 0.9mm stucco aluminium cladding. 
• cleanSPARK box from 4mm S275JR mild Steel with external stiffening angles
• cleanSPARK box internal arrangement proven using CFD modelling
• cleanSPARK inspection and cleanout doors double skinned and internally insulated 
• Grecon spark detector FM 3/8 
• Grecon extinguishing module LB1 Ex 111/3D
• Grecon COMPACT System (CC5001)
• Heated and thermally insulated pipes from water tank to spray nozzles
• On-site installation and commissioning by Grecon  

The order for the filter itself came well before the final supply and layout were finalised and therefore the filter was completed well ahead of the due date for the installation to begin.  The filter was fabricated in Leicester as normal for FD but with the ducting connection details either end remaining an unknown until the installation, following a pre manufacture approval check measure visit to site by Sam we gave the task of fabricating all the ducting and the installation of the full scope of supply to Taylor Engineering, a company based close to the site with the capabilities to handle both the manufacture and installation. Taylors also offered the advantage of considerable first hand experience of working for the client and on their site. 

Following a fairly lengthy time in storage in Leicestershire, the loading and delivery of the cleanSPARK filter and cleanSPARK box was organised.  This would be via 3 lorries and an escort vehicle.  Following the long journey North, the arrival of the vehicles on site was managed in order to align with clients earlier the same day arrival of a crane on site to offload the filter sections.  Prior planning ensured it was a straightforward and simple task unloading the delivery vehicles. 

Taylors assembled a small but experienced team of erectors to handle the installation.  With time constraints being applied to our client by the site operators we had a time limited window to erect the equipment in.  The co-ordinated and well managed effort on the part of our client, Taylors and ourselves (not to mention some pleasantly co-operative weather) saw the filter largely assembled in its snug location inside the first three days of week 1.  

Later in week 1 saw the ducting installation begin, working from the connection with the existing ducting inside the working out to the cleanSPARK box which itself, needed carefully positioning to ensure full access to both its doors in its tight location. 

By the end of the second week all the ducting including the cleanSPARK box, fan as well as filter bags and cages were installed. 

Week 1 – cleanPULSE Filter installation

Week 3 saw Taylors managing the start of the insulation and cladding on site.  The work being carried out on their behalf by another Scottish company who came recommended based on their previous work on the site.   Week 3 also saw the start of containment for cabling, the compressed air needed for the manifold tanks and the water supply and drain for the spark detection system were also still in our client’s scope.

In addition to our CFD aided design of cleanSPARK box this system has a spark detection and arrest system supplied, installed, and commissioned by Grecon. This detects sparks just after the spark arrest box.  Should the system detect a spark, 6 litres of water is sprayed at 6 bar by a single water nozzle in fractions of a second.  This gives a higher level of protection against fire for the filter bags in a system which doesn’t require a flue gas cleaning re-agent like Sodium Bicarbonate.  Should the system detect multiple sparks within a short time, the main fan will be shut down.  This can offer the possibility of an insurance costs saving for our client.  Although the water from an arrest action should vaporise in the duct, we took the precaution to install the nozzles in a vertical duct and installed a drain tap in the base of the ducting where this would likely drain too should it ever happen. 

The project was completed and commissioned on schedule.  Taylor Engineering and their subcontractors did a fantastic job, just as we were advised they would and whilst we encountered a few snags along the way, the combination of a proactive and motivated client, Taylors and Filter Designs all pulling in the same direction ensured project success.

Our thanks on this project go all those involved, all those employed on site in whatever capacity and not to forget good old mother nature herself!  A full 10 or 11 hours of driving just to get site shouldn’t be enjoyable, but when so many hours on route the scenery and the final destination are so stunning, I will always be happily called upon to visit site.  

What’s the next project going to be?... probably the North Coast 500!