Progress in Life Cycle Assessment by Liselotte Schebek & Christoph Herrmann & Felipe Cerdas

Author:Liselotte Schebek & Christoph Herrmann & Felipe Cerdas
Language: eng
Format: epub, pdf
ISBN: 9783319922379
Publisher: Springer International Publishing

2 Description of the Process

AURO Pflanzenchemie AG provided the investigated binding agent emulsion production process. For this case study process data, e.g. energy consumption, type and amount of process material and reactants, and information relating to the different cost types from the company were used. The batch production was carried out in an agitator vessel with heating jacket in which all process steps were performed consecutively. At the start, all reactants, consisting of partially organic as well as aqueous chemicals, are fed to the reaction vessel and heated up. Afterwards, several emulsification and shearing steps are applied until the required droplet size is achieved. Finally, the binding agent emulsion is drained from the stirred tank and the equipment is cleaned. In continuous production, the respective preparation of the organic and the aqueous reactants takes place simultaneously outside of the actual reaction vessel. These two phases are then combined and pre-emulsified in a passive mixer (premixer). Subsequently, this pre-emulsion is emulsified in an active mixer (rotor-stator mixer) in order to achieve the required product properties.

The transfer of this process from batch to continuous production involved several constraints with respect to the manufacturing scheme. The advantages of batch production concerning the production flexibility due to fluctuating market demands had to be maintained at the same time ensuring a constant and high product quality through online monitoring of process parameters in the continuous procedure. Furthermore, the high energy consumption of the batch production due to consecutive heating and cooling steps in a single vessel were targeted for heat integration in the continuous production process.

It was shown, that the specific energy demand in continuous production has been reduced by 50% compared to the batch process (Wengerter et al. 2017). While batch production required a high level of cleaning effort, the continuous operation of the system could be significantly reduced through the implementation of microstructured devices and thus lower plant hold-up and significantly increased cleaning intervals. Furthermore, personnel expenditures were considerably reduced by a largely automated plant control for the continuous process.

The MFCA was conducted in accordance with ISO 14051: 2011–2012. Its application was intended to increase energy and resource efficiency and to support plant and equipment design in the case study. The increase in energy and resource efficiency can be achieved on the one hand by an appropriate process concept, such as the transfer from batch to continuous production, and on the other hand by the choice of equipment. The MFCA can be applied to evaluate both aspects depending on the definition of the quantity centres. In the context of this article, MFCA focuses on the choice of equipment and its implementation to increase energy and resource efficiency and improve plant and equipment design. The definition of the quantity centres was based on the 3-level-model according to (Wesche et al. 2015). In the first level, the model maps the individual unit operations (UO) of the production process, which are connected to create the full process topology in the second level. The available infrastructure (operating networks, disposal routes, etc.

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