Simulação e análise de uma unidade de geração de hidrogênio em refinarias de petróleo

Abstract

Hydrogen production has improved market share due to its wide use in oil refineries, more specifically in the hydrotreatment, in order to remove impurities such as sulfur in fuels. With a increasing concern about the environment and health, regulatory measures aim at reducing the high rates of pollutants in the atmosphere, mainly from the burning of fossil fuels. One of the main pollutants is sulfur oxides, originating from the sulfur present in fuels, and the main causers of acid rain. Hydrotreatment consists of the reaction between the petroleum derivatives and the hydrogen, in order to reduce the content of contaminants. Hydrogen Production Units (HPU) produce hydrogen from the steam reforming. This element is an input for hydrotreatment, which requires it with high purity. In this way, a purification step is necessary, by Pressure Swing Adsorption (PSA), the most used technology. The objective of this work is to evaluate and to simulate a Hydrogen Production Unit (HPU) in the commercial simulator ASPEN PLUS applying an adsorption column mathematical modeling for hydrogen purification previously developed and implemented in MATLAB. A sensitivity analysis was maded in the adsorption mathematical model to evaluate the effect of adsorbent type used in the adsorption columm and the effect of pressure on bed regeneration. To simulate the adsorption model in ASPEN PLUS, an interface with MATLAB was established through EXCEL and ASPEN User 2 module. The model studied showed good correlation with the experimental results reported in the literature. The strong influence of the characteristics of the adsorbent material on the adsorption performance, as well as the operational parameters was observed. The connection between the two software was successful and the simulation performed was able to represent the hydrogen production process in a satisfactory way, allowing to evaluate the effects of the process variables on the plant as a whole. The simulated HPU plant yielded hydrogen with 99.8% purity due to simplifications. This paper is a step towards the development of simulations, aiming at Operator Training (OTS). From the results of a simulation, when it is well-adjusted, it allows the operator and / or the user to better understand and follow the process, so as to act on their variables in a much more conscious way, being able to evaluate beforehand their effects and impacts.