Diseño de una planta de separación de aire para la producción de oxígeno de grado medicinal

Abstract

Air separation units are used to produce high purity gases, being oxygen the most interesting one; it is of utmost importance in the medical field as it is considered a medicine utilized for the treatment of respiratory diseases, in addition to other important applications. Nitrogen is also obtained from the process and both have great uses in the chemical, metallurgical, alimentary, pharmaceutical, and paper industries, among others. Thus, the objective of this paper is to propose the design of an air separator unit plant for the Machala canton, El Oro province. To this end, the appropriate technology was chosen from among the following are highlighted: acquisition and production costs, required investment, product quality, and profitability using the Likert method. Through the Cape-Open software COCO SIMULATOR, the simulation of the cryogenic distillation plant was developed and the mass balances of the internal currents entering and leaving the system were obtained. Furthermore, the necessary data for the design of the equipment were also collected and were captured in datasheets. Three different plant designs were proposed and the third case was chosen, corresponding to an oxygen production of 5200 kg/h at 99.5% and nitrogen production of 4700 kg/h at 99.6%. Grounded on the chosen plant design, instrumentation and piping diagram and a plot plan were prepared, and a HAZOP study was conducted based on the analysis of functionality and operability. On the other hand, possible operational failures in the expansion turbine, High-Pressure Column (HPC), and Low-Pressure Column (LPC) were detected, which may be caused by deficiencies in the control loops, obstruction in valves, pipe rupture, plate corrosion, and/or column flooding. Moreover, the possible location of the facilities within the city limits was proposed. Lastly, the economic profitability of the project was determined through the economic indicators; net present value which was $1 million, and internal rate of return higher than 35% in a period of 3 years, thus concluding that the project is economically feasible.