Vapour-liquid equilibria of n-butane and ethyl mercaptan: Experiments and modelling

Abstract

Design of debutaniser in fractionation train in gas processing requires accurate knowledge of phase equilibrium properties of n-butane with sulphur compounds like mercaptan. In this paper, we report high-quality isothermal vapor-liquid equilibrium data for n-butane + ethyl mercaptan (or ethanethiol) between 298.14 K to 388.18 K and pressures up to 2.0029 MPa. An equipment whose experimental technique is based on static-analytic method was considered. The equipment is composed by an agitated equilibrium cell with two online micro samplers connected to a Gas Chromatograph. The data was correlated with the Peng Robinson equation of state with classical alpha function. A comparison was also performed with two predictive models, PPR78 and PSRK UNIFAC.

Experimental Measurements and Modeling of Vapor-Liquid Equilibrium of Isobutane and Ethyl Mercaptan Binary System

“…An experimental technique based on the static analytic method is used in this study. The equipment was previously presented and described by Boonaert et al [8], Zhang et al [27], and Théveneau et al [28]. A flow diagram of the experimental apparatus is presented in Fig.…”

“…It is difficult to obtain experimental reliable thermodynamic data such as VLE data for a system containing sulfur compounds like hydrogen sulfide and mercaptan because of their acute toxicity and high volatility. The Centre of Thermodynamics of Processes (CTP) of Mines Paris, during the last years, has studied and measured VLE data of numerous binary and ternary systems involving hydrocarbons and mercaptans [6][7][8][9].…”

“…In Table 1, the literature studies on binary systems with sulfur compounds and butane (isobutane (iC4) and n-butane (nC4)) is reported. In 2020, we measured new VLE data concerning the n-butane and ethyl mercaptan binary system (Boonaert et al [8]). We can also observe that there is a lack of experimental VLE data for binary systems with isobutane, except with H2S.…”

“…MRDU (from Eq 6), BiasU (from Eq 7), and van Ness test (from Eqs 8 and 9) between the experimental VLE isobutane + ethyl mercaptan data and PR78 EoS modeling at 298 K, 313 K, 328 K, and 343 K.As suggested by Boonaert et al[8], the van Ness test[31] is a good way to check the consistency of the experimental measurement. This test is defined following Eqs.…”