Improved Process Analysers for Blending Applications

To economically run processes in modern refineries, the installation of process analysers is required to continuously provide reliable measurement results within the shortest possible time. The refineries’ targets of a consequent use of process analysers are to fulfill environmental regulations e.g. in terms of reduction of sulphur, aromatics and vapour pressure, as well as to respond to current market situations in terms of the open market for imported products, the stagnating sales due to more efficient automobile engines and the market shifts between product classes and grades and also to flexibly respond to the frequent changing of mixing recipes.

In some refineries, the products from the variety of process units which are each different in their qualities and compositions are stored in intermediate storage tanks for further use. Depending on the required final product for sales, the specific final blending has to be carried out either into storage tanks or directly by “in-line” blending into e.g. a pipeline or vessel. To get the approval for selling the final product a number of quality parameters have to be observed and met. One of these parameters is usually the boiling characteristic of the final product which has to be carried out according to the ASTM D86 standard.

Before starting the blending process a reference measurement is carried out with protofuel. This protofuel is used for the validation and approval of the analyser results. If the analyser is validated successfully, the blending starts. During the complete process the results of the analyzer are used to monitor and control the blending. At the end of the blending process, the analyzer has to perform a further validation cycle with protofuel. If the validation with protofuel shows results within the given specification, the final product is approved and released for sale. The precondition for the performance of such a procedure requires the use of appropriate and reliable analysers which are compliant to applicable standards. Bartec Gmbh’s (Germany) redesigned  DPA-4 Distillation Process Analyser is the only ASTM D86 compliant process analyser available in the market. It is fully compliant to the laboratory method as it uses the same apparatus and operates according to the defined procedure where a 100 ml sample is evaporated at a given distillation rate of 4 to 5 ml/min. The DPA-4 offers excellent repeatability and reproducibility for optimal process control is the result.

The DPA-4  Distillation Process Analyser is suitable for determination of each distillation point from the initial boiling point to the final boiling point within a range of typical 20°C to 420°C. New features are implemented to shorten the overall cycle time. This is possible due to the optimisation of the heat transfer during distillation, the reduced time to cool-down the analyser and implemented pressurised flushing which ensures a fast evacuation procedure to get the analyser ready for its next measuring cycle. Based on an established standardised and robust design, the analyser is suitable for installation in hazardous areas and is available with different certificates. The analyser is equipped with state of the art communication interfaces and optionally available with customised sampling conditioning systems and chiller units.