An Investigation of the Prediction of Hydrate Formation Conditions in the Presence of Thermodynamic Inhibitors

Carollina de M. Molinari O. Antunes¹; Moisés A. Marcelino Neto¹; Rigoberto E. M. Morales¹; Celina Kakitani¹; Luciano F. dos Santos Rossi¹; Amadeu K. Sum²

¹ NUEM / PPGEM / UTFPR; ² Chemical & Biological Engineering Department, Colorado School of Mines, Golden, CO, USA

doi:10.20906/CPS/COB-2015-0733

Resumo

Gas hydrates are ice-like, solid inclusion bodies of hydrogen bonded water and small guest molecules, typically light gases. They are notorious for causing problems for producers and processors in the oil and gas industry. Gas hydrates can form at pressures and temperatures found in natural gas and oil pipelines causing blockages. In order to inhibit the formation of hydrates, the industry injects chemicals, such as alcohols (ethanol, methanol, mono-ethylene glycol, etc) and salts (sodium, magnesium and potassium chloride). The purpose of this work is to briefly review the literature for hydrate formation in mixtures containing light gases (hydrocarbons and carbon dioxide) and water in the presence of thermodynamic inhibitors. To do this, four methods to predict hydrate formation for these systems will be examined and compared. Three commercial packages, Multiflash, PVTSim and CSMGem, and a hydrate prediction routine in Fortran, that uses the van der Waals and Platteeuw theory and Soave-Redlich-Kwong equation of state, were tested. Predictions of the four methods have been compared against independent experimental data from the open literature. In general the four methods were found to be reasonably in the predictions of experimental data.

Palavras-chave: hydrates; inhibitor; prediction; commercial packages; hydrate routine