Optimising green coffee reception operations based on cleaning and storaging requirements: IMA Coffee Petroncini unveils a detailed comparison among case histories.
By Marco Balboni, Senior Coffee Process Engineer at IMA Coffee Petroncini
Throughout the entire roasting process, tailored reception, storaging and handling systems are critical points to implement the business continuity plan, avoiding any downtime and maximising plant effectiveness. Whether designing a new roasting facility, expanding, or optimising an existing one, green coffee processing plays a crucial role in the overall efficiency of production.
Preliminary engineering: playing cards face up
Considering plant capacity and optimisation of handling operations, every customer can decide the preferable way to receive and treat raw coffee in their facility.
“Space availability, customer budget and the desired level of operations automation are the crucial factors that allow for a preliminary engineering analysis. A tailored engineering solution should combine the customer’s logistics needs and production expectations with the available space and budget, taking into account the necessary manual operations involved” says Marco Balboni, Senior Coffee Process Engineer at IMA Coffee Petroncini. “It’s not always easy to find the perfect match, but what makes us proud every day is the satisfaction we can share with the customer at the end of every project in which we have reached the goal together”.
Silos or grounded bags: the choice
“Suitable storage time varies from a minimum of three days up to one month, considering the overall plant production, the number of coffee origins that will be used and the type of storaging the customer has planned, be it in silos or in the warehouse. The choice of the type of storaging solution strictly depends on the availability of space and production planning” Balboni says.
“Especially when we face up to big companies, we have to deal with big plant capacity where the time range between green coffee reception, treatment and roasting is shorter and shorter. So, receiving operations are crucial to achieve production continuity. For big plant capacities, a convenient solution is receiving bags or coffee in bulk – in 20 m3 supersacks – from tilting trailers or containers. In both cases, it is necessary to discharge the coffee in one hour maximum to stay within the limits of the trailer’s free-of-charge stop.”
According to production requirements, there are several solutions for handling the coffee after discharge. The bulk coffee can be sent directly to the storaging silos or re-bagged in big bags to be picked up later, depending on the planning. The 60-70 jute bags can be sent to a singularising unit that handles them as far as the cutting machine or collected on pallet for subsequent operations.
“Over recent years, Petroncini has been witnessing more and more attention paid to in-house raw material treatments, because of the increasing impurities present in green coffee and the growing costs of buying it already cleaned.” Balboni says.
“That has allowed for a consequent increase in high performance technologies to guarantee a constant quality level of the raw product, eliminating defects and impurities, as well as increasing the value of the end product, counting on maximum control of the in-house process, especially for big companies that process tons and tons of coffee per day”.
“Nowadays, optical sorting is the most advanced technology on the market thanks to its ability to sort not only by colour, but also by shape. We usually recommend these machines as a all-round cleaning solution, combined with a sieve. Optical sorting machines are available with one to seven chutes to satisfy any production capacity requirement and for multiple passes.” Balboni advises.
The project – a detailed overview
The solution provided, says Balboni, enabled us to save the money that would have gone on a bigger cleaning machine and, as a result, a centralised filter system.
“In this project, there were no particular restrictions due to the layout of the premises, except for the limited height, so the space for storage was enough to install two pre-cleaning round silos of 22 tons each, able to receive the total amount of coffee coming from the truck. Therefore, the company could receive a truck every two hours, with a cleaning capacity of 10 tons per hour” Balboni explains.
In addition, two re-bagging stations were provided, one for the raw beans and one for the already cleaned coffee. In that way the customer could also store the coffee in the warehouse for later operations.
The indoor hopper, combined with the most advanced aspiration system, enabled big bags to be discharged at the rate of up to 10 tons per hour.
“Under the cleaning station, we installed a continuous weighing system to register the quantity of cleaned coffee sent to the storaging silos through a pressure pneumatic system able to handle up 10 tons per hour” says Balboni.
“The choice of a circular layout for the silos was strategic. Even if circular silos need more space due to their characteristic shape, they are the best solution in terms of hygiene, since they have no corners where dust can collect, especially when a company is working with several numbers of coffee origins and have to guarantee product traceability.” Balboni explains.
The limited height meant it was necessary to adopt Petroncini LINE-S for the dosing valves.
“This system has been engineered and developed by Petroncini to maximise efficiency and cost-effectiveness in lacking vertical space. LINE-S VALVE is an effective solution for green bean extraction from storaging silos and, in a minimum amount of space, can collect several modules for product loading, dosing and air filtering, also combining devices for maintenance. Due to the smaller space footprint compared to other common valves, using LINE-S valves allowed for a lot of vertical space to be saved, with reduced costs as well” Balboni explains.
Coffee warehouses with bags and big bags – case study #2
A big coffee production plant with a small number of green storaging silos is not common, but it is an option and even a necessity in some specific layout conditions.
This was the case for a big, longstanding coffee processing company that was planning to expand its production in Italy with the opening of a new production facility.
“The facility characteristics did not allow for storaging silos to be installed due to several restrictions in its layout, but the expected production was high. The company was planning to receive the coffee bags and coffee in bulk from a trailer.” Balboni says.
“Petroncini installed two reception stations: the first one is a very flexible solution to efficiently handle the bags into the facility. It consists of a belt conveyor that can be extended telescopically inside the truck thus allowing the operators to position the bags on the swivel head. After that, the bags can be palletized through the action of a robot driven by registered automation. This solution is suitable for picking the bags at a later time, according to production. Indeed, in a second step, the tilting platform for pallet depalletizing, combined with a bag cutting unit, was the ideal solution for depalletizing bags for a capacity up to 750 bags/h.” Balboni explains.
The second reception station installed was an outdoor coffee hopper for receiving coffee in bulk from trucks, connected, through a handling system in aspiration, to a re-bagging station.
“This solution was engineered to feed 1 m3 big bags, and later Cubic Bags. Through a special tubular sliding conveyor, the bags can be positioned on a pallet and prepared for storage. A cubic bag is a form-stable big bag made of woven polypropylene. These sturdy big bags have a special inner construction (baffles), which makes them less ‘bulging’. The bags can be stacked after filling, so that the space is efficiently optimised.” Balboni concludes.
For a big coffee warehouse, big bags are not usually wasted, but are recycled each time. So, an indoor big bag unloading structure is the most used solution to discharge up to 10-12 tons per hour of green coffee.