Abstract:
The paper provides a method for selecting the composition of a refrigerant with a given isobaric cooling curve using an artificial neural network (ANN). This method is based on the use of 1D layers of a convolutional neural network. To train the neural network, we applied a technological model ofa simple heat exchanger in the UniSim design program, using the Peng - Robinson equation of state. We created synthetic database on isobaric boiling curves of refrigerants of different compositions using the technological model. To record the database, an algorithm was developed in the Python programming language, and information on isobaric boiling curves for 1 049 500 compositions was uploaded using the COM interface. The compositions have generated by Monte Carlo method. Designed architecture of ANN allows select composition of a mixed refrigerant by 101 points of boiling curve. ANN givesmole flows of mixed refrigerant by composition (methane, ethane, propane, nitrogen) on the outputlayer. For training ANN, we used method of cyclical learning rate. For results demonstration we selected MR composition by natural gas cooling curve with a minimum temperature drop of 3 Ê and a maximum temperature drop of no more than 10 Ê, which turn better than we predicted via UniSimSQP optimizer and better than predicted by k-nearest neighbors algorithm. A significant value of this article is the fact that an artificial neural network can be used to select the optimal composition of the refrigerant when analyzing the cooling curve of natural gas. This method can help engineers select the composition of the mixed refrigerant in real time, which will help reduce the energy consumption of natural gas liquefaction.
Keywords:optimization of LNG production, selection of mixed refrigerant composition, big data, neural network, artificial intelligence.
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