Viscosity prediction of hydrogen plus natural gas mixtures (hythane)

A scheme based on the friction theory (f-theory) is introduced for the visc osity prediction of mixtures composed of hydrogen and natural gas (hythane) . In the f-theory the viscosity is separated into a dilute gas viscosity an d a friction contribution term. The mixture friction coefficients are estim ated with mixing rules based on pure-component friction coefficients. Becau se hythane mainly contains hydrogen and methane, the pure friction coeffici ents of these components are obtained with f-theory models directly fitted to these two components, while the friction coefficients of the other compo nents are obtained with a general f-theory model. For the dilute gas viscos ity term, the simple mixing rule of Wilke is capable of an accurate estimat ion of the dilute gas viscosity. Using this f-theory scheme in conjunction with the Peng-Robinson and Soave-Redlich-Kwong EOSs, the viscosities of fou r hythane mixtures have been predicted within or close to experimental unce rtainty (+/-1.0%), which is satisfactory for most industrial applications. This scheme is of a predictive character, because only properties and param eters of the pure compounds are required. This work further shows the appli cation of the f-theory for viscosity predictions and its application to ind ustrial processes.