Rheological investigation of pitch materials: Part I: Design and development of a high-temperature high-pressure (HTHP) rheometer Original Research Article

A high-temperature, high-pressure (HTHP) rheometer is designed and developed to measure viscosity of pitch material at elevated temperatures. Although not demonstrated herein, the provision for high-pressure operation is made so that the effect of a dissolving gas on the viscosity of the pitch materials can be evaluated. The HTHP viscometer is constructed from a commercial high-pressure vessel (Autoclave Engineers, Inc.). The high-pressure vessel is rated for 7.6 MPa at 295 K with a maximum temperature limit of 773 K. The viscometer is calibrated using standard viscosity fluids at varying temperatures.