The requirements in custody transfer applications have been made more complex by the introduction of the Europe-wide Measuring Instrument Directive (MID). This directive requires testing of the individual components and approval of the entire system by a designated authority. Endress+Hauser now delivers everything from a single source through its Flow Management Solutions (FSM) team. The technical basis for this is provided by the Proline Promass Coriolis mass flowmeter.
The Europe-wide Measuring Instruments Directive, which is recognised by 28 member states, regulates a total of ten sub-areas, including custody transfer of measuring systems for continuous and dynamic measurement of quantities and liquids other than water (sub-area MI-005). According to the previously valid laws of the individual countries, the components used, such as flow measurement systems or preset counters, are type-tested by the respective manufacturers and approved for custody transfer. They can be combined into a loading system and then commissioned in an on-site inspection.
The MID currently in force states that all components of a loading system must be tested in line with the OIML (International Organisation of Legal Metrology) guidelines and the entire system approved by a designated authority. If the system is assembled by the user from the necessary components, as was sometimes the case in the past, the user is obliged to effect the system approval itself in its role as the company that brings the product to market. This means spending additional time and money. To relieve facility owner-operators of this burden, Endress+Hauser offers a complete MID system for loading and unloading tankers, boiler trucks and ships that is pre-approved for custody transfer. Based on the Proline Promass Coriolis mass measurement system, this loading system can be configured individually according to the user’s wants and needs. Users can currently choose between three batch controllers listed in the system approval as well as different data storage units and original document printers.
This future-oriented MID approval was realised in conjunction with the German national metrology institute (PTB) in Braunschweig. Thus, Endress+Hauser not only offers an entire package from engi-neering to custody transfer measurement, but also cuts out the effort required for the system approval. There is no easier or more reliable way to implement custody transfer loading systems.
Mass flow measurement system
The chief success factor for the loading system is the highly accurate Proline Promass Coriolis mass flow measurement system, which offers a number of impressive advantages over conventional measuring devices in this kind of application. Unlike the weighing systems that are still frequently in use, filling stations with Coriolis measuring devices are tamper-proof. Truck or rail scales, by their very nature, have low reso-lution and accuracy and are very expensive. Moreover, rain and wind loads have an appreciable effect on weighing. In contrast to mechanical flow measurement solutions, the insensitivity to dirt means there is no need to use elaborate filtering systems. This enables maintenance effort to be decisively minimised. Moreover, cost-effective installation without a support and maximum stability in operation are guaranteed. The Promass is virtually insensitive to changes in process temperature and pressure as well as mechanical tension or vibration in the pipeline system. Promass therefore demonstrably facilitates the high-est level of accuracy in loading operation, with a margin of error far below the error limit in legal metrology. Another important point is that all other components used, such as pumps, tanks, pipes and gas sepa-rators, meet the most stringent quality requirements. All suppliers must undergo an extensive qualification process for this purpose. Of course, all components used in the overall Endress+Hauser solution are matched to each other exactly.
Highly accurate tanker loading
The Verbio Group is one of the leading manufacturers and suppliers of biofuels as well as the sole large industrial producer of biodiesel and bioethanol in Europe. Its nominal capacity is currently some 450,000 t of biodiesel and 300,000 t of bio-ethanol per year. Verbio delivers its products directly to the major European mineral oil companies, oil wholesalers, independent gas stations and trucking firms. In all areas of biodiesel and bioethanol production, storage and loading, the company attaches great importance to production processes developed in-house as well as to state-of-the-art technologies.
For the production of E85 fuel, Verbio manufactures bioethanol from grain and other raw materials containing starch or sugar on a large scale at its location in Zörbig, Germany. During this production process, enzymes convert the starch into sugar. Yeasts are employed for fermentation to convert the sugar into ethanol. The stillage generated by this process contains valuable grain components that cannot be fermented; it is reused in an environmentally compliant way as a natural fertiliser and as animal feed.
E85 is an ethanol-gas mixture consisting of 85 % ethanol and 15 % petrol. The fuel offers many advantages over fossil fuel pet-rol. Ethanol has a significantly higher oc-tane rating than premium fuel and is thus more resistant to knocking. This increases the compression ratio of the engine and guarantees higher efficiency. In addition, E85 fuel has considerably less environmental impact due to its 85 % CO2 neutrality. The dramatically reduced concentrations of sulphur and aromatic compounds result in significantly cleaner combustion. E85 is consequently a genuine alternative to conventional fuels. Verbio Ethanol Zörbig is the German market leader for E85.
For custody transfer applications in tanker loading, Verbio was looking for an end-to-end solution from engineering to commissioning as well as, where applicable, custody transfer measurement. The focus was on simple and time-saving implementation by a single-source supplier. The requirements specified for the technology were long-term high accuracy, maintenance-free performance and easy handling.
Endress+Hauser planned, supplied and installed a complete loading system for loading tankers with E85 consisting of:
- Promass 84F Coriolis mass flowmeter in line size DN 50
- Ball valve with electropneumatic drive
- Inspection glass
- Batching Master 110i
- Loading arm (ground loader)
- Overfill protection
The filling and loading control system (Batching Master) is installed in the hazardous area. In order to fill a tanker, the user simply selects the desired volume on the numeric keyboard and starts loading directly on the Batching Master. Of course, all safety-related data, such as connection of the ground or overfill protection, is first queried automatically. Loading only starts after release by the process control system to guarantee maximum operational safety. The data is transmitted from the Batching Master to the control room via Profibus DP, making it easier to integrate the loading system into the existing control system. At the end of the loading process, the required printouts are generated automatically in the control room.
No need to convert
The advantages of direct mass measurement using the Promass are also clear in this application. In contrast to mechanical flow measurement systems, there is no need either to convert the measured operating volume to a reference temperature (V15), which introduces additional inaccu-racies, or to calculate the filled mass using complicated density and temperature formulae. Moreover, thanks to this technology, the direct mass measurement is independent of temperature, density and viscosity, and maximum accuracy is assured under all application conditions.
Endress+Hauser met the wants and needs of the user with the solution described above. As a single-source supplier, the company took care of the entire planning and design of the loading system and provided the customer with a complete system tailored to its specific conditions and requirements. With its highly accurate loading capability, this system represents an excellent alternative to conventional loading technologies that is cost-effective even at the time of purchase and remains unbeatably efficient throughout the entire life cycle.