Study of two possible steam optimizations with the development of one of them in Covestro's Site

Identifier:  TFG:9139

Handle: https://hdl.handle.net/20.500.11797/TFG9139

Authors:  Carvaca Martí, Àurea

Abstract:
This project has studied the feasibility of implementing a steam compression unit to improve the energy and economic efficiency of the plant. The steam to be compressed comes from the surplus of consumers and from what is currently consumed by the absorption water cooling system (broad). Therefore, the main objective is based on determining the optimal operating hours ratio between the compressor and the absorption machine. All the cold that is no longer produced in the broad will have to be generated with the ammonia compression refrigeration cycle, existing on the site. To carry out this study, the process data for the year 2024 has been analyzed using the PI. In this way, the cold generated by the broad has been determined, and the equivalent ammonia flow rate to produce the same cold in the compression refrigeration cycle. Based on this data, a model has been determined that relates the electrical consumption of the compression refrigeration cycle and the flow of ammonia to be compressed, differentiating the energy requirements for winter and summer weather conditions. To evaluate the profitability of the project, two mathematical formulas have been established that determine (depending on the flow rate of water to be cooled and the inlet and outlet temperatures of the water) the economic savings that would result from stopping the absorption machine and starting the turbocompressor. After applying the formulas to the data for 2024, it has been observed that the continuous operation of the new installation would have been profitable during all months of the year. In addition, the reduction in the combustion of natural gas in the cogeneration boilers has translated into a decrease of 7,840 t CO2 eq/year, favoring the company's decarbonization objectives, and making it possible to grant subsidies by the state. In the preliminary design phase, the Knock Out Drum and the pumps of the lubrication oil circuit have been sized. However, the turbocharger and the tempering unit will be supplied by external distributors, with specifications to be defined in more advanced development phases. In parallel, a HAZOP safety study has been carried out to identify risks and define safeguards and actions. Finally, with the economic evaluation (between the FEL 1 and FEL 2 phases), it has been estimated that, with a state subsidy of 40% of the initial investment, the return period would be approximately 1 year and 8 months, with a NPV of 6.5 M€ and an IRR of 58.79%. Therefore, the feasibility of developing the project in the company is demonstrated.