Pinch analysis achieves an optimum interconnection of heat between process streams as a basis for reducing external requirements of heat or refrigerants (photo: Bilfinger)

Energy is money. Accordingly, efficient utilisation of energy is crucial for industrial companies. However, existing energy flows are only rarely used in industrial plants in such a way as to minimise the need for external energy input or output. This is despite the fact that substantial savings can be gained in nearly all plants regardless of the sector. The key to detecting such unused potential can be found in what is known as a pinch analysis. This system evaluates energy streams as a basis for optimising heat flows. One particularly efficient pinch analysis process has been developed by Bilfinger Bohr - und Rohrtechnik GmbH, a Bilfinger SE company, in conjunction with the Technical University of Vienna.

The purpose of the pinch analysis is to achieve an optimum interconnection of heat between process streams as a basis for reducing external requirements of heat or refrigerants. The resultant reduction in the consumption of fossil fuels additionally cuts CO₂ emissions. The process performs a thermal analysis of plant equipment and the related technical processes to produce a comprehensive overview of the internal heat integration of the individual and aggregate processes. After this review has been performed, a detailed analysis is completed to systematically describe the ideal plant condition, i.e. the optimum interconnection of heat between process streams. Bilfinger then draws up an implementation plan on the basis of this optimum situation. In addition to the technical process-related aspects of the plant in question, this plan also sets out the capex and opex costs as well as safety and operating restrictions. It also identifies the parameters that can be modified to optimise the energy footprint of the plant and to achieve an optimum link between the various heat sources and sinks.

Practical implementation of the energy-saving measures is frequently possible by means of straightforward and immediate actions, by converting existing heat exchangers or by replacing them with new models. However, more recent technologies such as high-temperature heat pumps, heat storage facilities and flue gas capacitors can also be integrated in the plant to optimum effect.

Pinch analysis is suitable for both smaller individual plants and large production sites. The greatest potential for savings can be harnessed in plants with numerous heat sources and sinks. Depending on the size and the age of the plant, the analysis may take from a few days in the case of small industrial plants to several months in the case of large, complex facilities to complete. No restrictions or disruptions occur in operations or production while the analysis is being performed. A larger part of the necessary information can be gained from operating records. The missing information is determined in the course of the analysis by means of on-site measurements and using thermodynamic calculations.

“The pinch analysis identifies unused potential for savings particularly in the case of older equipment that does not have an energy management system. On this basis, it is possible to lower operating costs after the efficiency-boosting measures have been implemented,” explains Christian Strondl, managing director of Bilfinger Bohr- und Rohrtechnik GmbH. “A further added bonus arises when new plants are being planned at existing production sites. Using the analysis, it is possible to integrate them more efficiently in existing plants in thermal terms.”Backed by their many years of experience in plant engineering and system integration, the experts at Bilfinger Bohr- und Rohrtechnik are able to estimate and calculate the capex costs of thermal optimisation of the plant quickly. This means that it is possible to distinguish economically viable solutions from those that are less viable.

Tags: Bilfinger, Bilfinger Bohr - und Rohrtechnik GmbH