Increasing menthol yield without loss of harvest

In 2012, Symrise AG invested 16 million Euros to double the production capacity for nature-identical I-Menthol at its headquarters in Holzminden in the south of Lower Saxony, Germany. For the process ¬automation experts at Tesium, the real challenge of the project lay in setting up the new plant within an established, ongoing production operation. Tesium worked with EPLAN PPE to configure all of the measurement, control, instrumentation and automation technology. A new move to secure Symrise's position as the global market leader: The town-centre chemicals plant, which was planned and completed by Tesium, has been producing nature-identical I-Menthol since summer 2012. Nature-identical menthol was produced using fully synthetic methods for the first time here in 1973. The success story of the globally sought-after flavouring and coolant is similar to that for the process of extending the engineering for process technology within the company. "As an independent subsidiary of a research company which produces aroma chemicals, cosmetic ingredients, flavours and fragrances, we are used to converting our engineering for process plants into production scale reliably and quickly," explains Kai Wedding, Marketing Director at Tesium. In engineering, working quickly and reliably mainly means establishing consistent processes. When Symrise plans new process plants or converts existing ones, there are representatives of four key areas on the project team. From Tesium's perspective, these are production-related management as the direct client, then a process engineer who is familiar with the processes, chemical reactions and quantity balances. The third representative is recruited from plant engineering and the fourth from EI&C planning. Shared basis for planning The composition of this kind of team makes it clear why it is so important to work with consistent planning, data and terminology for projects within the Symrise group. EPLAN PPE takes on a key role. Tesium uses a piping and instrumentation diagram (P&ID) as the top level of all graphical documentation of the chemical processes and transport routes for the different materials used. Symbol databases make work easier at this point, with the maintenance of all project versions in a database making it easier for all those involved in the project to access the latest version without older releases causing inconsistencies in the project. "Starting with the higher-level process diagram, we then work deeper into the plant," explains Armin Thies, Head of EI&C Planning at Tesium. All components required for the operation of the menthol plant, including reactors, pumps, pipelines, measuring instruments, stirrers and control valves, are tethered within the flow diagram with standardised symbols and detailed technical specifications. For pipelines, these specifications are usually nominal width and pressure, transport medium and pipe material. Similarly, the key elements of the measurement and control engineering are configured within the process diagram. This work finally ends up in loop lists and sheets. These reflect the complete EI&C equipment for each individual process within the Symrise plants. "These include, for example, physical measurement type, measurement range, measurement principles, material requirements, type of sensors and connection specifications," explains Ludwig Schaefers, EI&C Planning Project Manager at Tesium. Equipment clearly defined The measurement point sheets clearly define the current technical equipment, including all dimensions, identification numbers, manufacturer components and the general function and role. For Armin Thies, the benefit of this kind of documentation is that orders can be placed quickly and reliably directly by the project engineers . The relevant functional areas are generally ordered and picked on an order-specific basis. A direct connection to the group ERP is not currently in place as the systems made by Tesium are very rarely off the peg. "The outlay for the necessary database and the interface would currently not be justifiable, especially as it would not significantly improve efficiency as the great majority of the planned process plants are tailor-made and therefore unique," explains Armin Thies. This is why more value is placed on consistent processes within their engineering. If any changes are made to the detailed engineering during the project, EPLAN PPE automatically records the revision status while the individual lists in the form of non-editable PDF files are checked for changes, which are highlighted in colour by the specialist departments. The trigger for changes of this kind can be, for example, different pipe dimensions or sensor type changes. "Colour highlighting is important to ensure that optimisations in one area do not lead to subsequent problems with fitting in another area - for example, if a change in pipe dimensions means that the flange diameter of a valve no longer fits as originally planned, because it was ordered based on an older project version," explains Armin Thies. At this point, the role of the central project team is to determine the current status of the project. "Because orders are placed on this basis, there are no surprises when it comes to mounting," Thies underlines. At Tesium, EPLAN PPE is just one element of the engineering process. As process and control engineering cannot be considered separately from electrical engineering, there is a direct link to EPLAN Electric P8 within the EPLAN Platform. This consistent approach is adopted by Tesium for orders outside the Symrise group as well - for example, for the configuration of a rape oil mill or orders from the glass industry. Barrier-free data flow accelerates the engineering process and supports later maintenance and service work by providing seamless documentation, among other things. "Our maintenance team knows what is to be expected in the case of inspections or repairs and is familiar with the relevant schematics," explains Thies. For Kai Wedding, this forward-thinking way of planning and working is a major factor in achieving high levels of operational reliability and thus production availability - especially for the new menthol plant which involves continually separating the leavorotary menthol molecules from crystallisation as part of a highly complex process. So it is not easy to just switch the plant off.

Flexible ingredient

Menthol is literally on everyone's lips - whether as a flavouring in chewing gum, as a key aroma in the refreshing peppermint note of a toothpaste or in candies for clear breathing. The apparently cooling effect on the skin has helped fuel the ever-increasing global demand for menthol, especially in the emerging markets. When the plant was commissioned, Dr Heinz-Jürgen Bertram, Chair of Symrise AG, expressed a conviction that "in the future, their economic power will have a significant effect on the global markets". "We have been producing synthetic menthol for over 40 years and have established ourselves as the market leader in that time. The new plant expands our product basis while offering customers consistently high quality - irrespective of harvest and price volatility," explains Dr Norbert Richter, Head of the Global Business Unit.