New control system for JDE plant
A new PLC and SCADA control system (S7-1500F and WinCC) has been installed for Jacobs Douwe Egberts (JDE) new coffee extraction plant in Joure, Netherlands.
The scope of the overall project comprised of the implementation of a 1 Stage NET extraction line to replace the existing extraction sets (‘conventional’ extraction technology) feeding a freeze-dried plant making instant coffee and a liquid packing operation for the professional business.
This Functional Design Specification (FDS) documents have been produced to describe the functions and facilities of the software for the Extraction Process control system to meet the requirements of the JDE Process User Requirement Specification. It details the design objectives and acts as the baseline document for the functions and extent of the System. It describes how the system functions, how it is operated and what facilities and services it provides.
The extraction system consists of 8 columns, in which the ground roasted coffee is extracted. This is carried out by process water flowing through the columns which are connected in series.
The columns are filled up with coffee from the buffer tanks of the roasting and grinding plant area, the coffee inside the column is pre-wet by process water coming from the feed water area.
Then the ground roasted coffee is “stripped” (aroma extraction “SDR”) where steam is injected to the roasted and pre-wet coffee and the condensate is fed to the SDR area for further treatment.
When this step has been completed, the column is ready for the next cycle “primary extraction” where 6 columns are connected in series and finally emptied. Control system acts as a scheduler for columns changeover.
In order to extract the required quantity of soluble solids via extraction, a known quantity of hot water is pumped through a column packed with the coffee grounds. The control system process parameters such as water temperature, water quantity, water flow rate and pressure of column are all specific to the bean types and finished products that are being produced.
Passing hot water over the ground beans enables the soluble solids to be extracted and removed from the grounds. This weak mixture of soluble solids and water is termed ‘coffee extract’ and is passed downstream for further processing. The quantity of this extract is accurately determined by volumetric flow meters which accurately determine the quantity of liquor passing the meter.
Once a known quantity of extract has passed the flow meter the draw finishes and the cycle moves on. The term draw refers to the act of drawing off soluble solids via hot water and the term cycle refers to the stage of the process. Each of these columns is a component in what is termed an ‘extraction set’. In this instance, this refers to 8 columns in series with hot water passing through one column and then onto the next. As the cycle moves on the oldest column in the set is emptied and then re-filled, this change of sequence refers to the cycle number.
The term 1-stage refers to the fact that the columns have 1 feedwater inlet and 1 outlet to draw off the weak scale extract. The term NET (New Extraction Technology) refers to the design of the column.
NET columns are shorter and wider than their conventional counterparts and thus the hot water has less time in contact with the grounds, reducing the damage to the desirable flavours.
Optima Controls was tasked to develop the common standardised Control Modules which later have been used across all the PLCs in the control system and software design for the Extraction Process plant (where the selected profile is built by adding columns to the profile and establishing primary feedwater and Inter-Stage Stripping (ISS) at the appropriate stages). We also did software design for MVR Process (Mechanical Vapour Recovery). TIA Portal software for Siemens 1500 F series safety PLCs and WinCC SCADA package has been used as a control system hardware/software platform.
Optima Controls was responsible for getting/sending blend-specific recipe data from/to MES system and recording all goods flows of materials for Track & Trace purposes to MES system. Optima Controls was a subcontractor to well-known partner in process industry ‘adi automation’.