Pilot-scale study of multi-phase venting from a vessel at elevated pressure and temperature

A high pressure Runaway and Venting Module (RAVEM) was designed and constru cted for pilot-scale runaway reaction and venting tests. The reactor vessel was rated at 10.1 MPa and 573.15 K with 0.112 m(3) capacity. Venting of th e vessel was actuated by a quick-opening valve that became fully open withi n 20 ms. The vented fluid was directed to a catch tank with a capacity of 1 .1 m(3). Pressure and temperature were measured within the vessel, at the i nlet and outlet of the quick-opening valve, and within the catch tank. A po int level sensor measuring changes in the refractive index of the contact f luid was installed below the vessel cover. Experimental results for the ven ting of water, water and terephthalic acid at elevated pressure and tempera ture are presented. The point level sensor successfully recorded the exact duration of vapour/liquid two-phase venting in the water tests. When pure t erephthalic acid (PTA), a water-soluble solid at high temperature, was adde d to the water, the venting was found to be three-phase. Preliminary analys es were also performed using the churn-turbulent vessel flow model and homo geneous equilibrium vent how model of the SAFIRE code to elucidate the two- and three-phase venting characteristics.