A look into the newest MPE-designed process system

A large North American roaster needed to build a new coffee roasting plant. MPE (Modern Process Equipment) Systems Group engineers managed the project from conception to commissioning.

From pre-design to commissioning, the project spanned roughly one year. The project was completed on-time, despite the coronavirus pandemic. MPE’s commitment to the project is perhaps best exemplified by one systems engineer who stayed on-site during a lockdown phase to ensure the system was installed and started without any problems.

Intake from Burlap Sacks

View the Automatic Bag Slitter in action here.

  • The Automatic Bag Slitter is capable of debagging 60,000 pounds (27,000 kilograms) per hour of green coffee.
  • A single operator can safely operate the bag opener, receive pallets from trucks or nearby warehouse, and remove stacked pallets and empty bags.
  • Finished goods are automatically conveyed to the next process step, in this case cleaning, final weighing, and storage.
  • Typical attrition rate is only 0.02 to 0.05 per cent of green coffee lost. Up to 99.98 per cent of green coffee is de-bagged successfully.
  • Automatic stacking of eight empty pallets allows for easy removal with a forklift.
  • Integrated dust collection systems keep the area clean and nearly dust free.
  • Zero strenuous, repetitive physical labour is required.

Read more on the Automatic Bag Slitter HERE.

Green bean cleaner (left) and surge bin (right) highlighted.

String Catcher & Cleaning

  • The coffee first passes through a string catcher, which as the name describes, catches any remnants of burlap string in which the coffee was shipped.
  • The green coffee then passes through a bean cleaner, which removes any debris, dirt, or out of spec beans from the process.
  • Coffee is then carried up through a pneumatic conveyor into a magnet that ensures no ferrous or non-ferrous metals made it this far into the process.
  • Then the coffee flows through a metal detector with an automatic reject valve, this process ensures minimal product loss, while maintaining uncompromising product safety.
  • The coffee then falls into a bulk weigher that measures out 500 pound (227 kilogram) increments.

Green storage

  • The green bean storage array comprises eight 20,000 pound (9072 kilogram) capacity silos.
  • The green bean storage silos are fed using pneumatics with three-way diverter valves.
  • Flex tube diverters are used in this system, which lead to less bean breakage compared to rigid tube diverters.
  • The green coffee leaves the silos and is measured using weigh belts, which are very accurate and allow the system to properly dispense contiguously, ensuring efficient operation and recipe adherence.
  • Two five-inch diameter Chain-Vey tubular drag conveyors transport coffee from the green storage silos to the roasting equipment. Read more on drag conveyors for coffee transport
View from under the post-roast mezzanine, after coffee has been blended. A sampling device (highlighted) allows for convenient quality control before transport to supersack filling or final packaging.

Post Roast Storage & Blending

  • Six four-inch diameter Chain-Veys carry coffee from the roasters to the post-roast silos.
  • The post-roast bean storage array comprises four 5000-pound (2268 kilogram) capacity silos.
  • A paddle blender with Bombay doors, as they are known in the industry, sits below the silos.
  • The roasted storage and blending system empties into Chain-Veys below, which transport the coffee to a supersack filling stations and rolling hopper.

For more information on MPE Systems Group’s process systems engineeringcontact them here, or call +1-773-839-4337.

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