Pressure-temperature relationship for decomposition of sodium bicarbonate from 200 to 600.degree.F

Abstract

The equilibrium dissociation pressure of initially dry sodium bicarbonate (nahcolite) was experimentally determined between 200 and 600/sup 0/F. It was found necessary to use a constant ratio of initial gas volume to solid nahcolite volume, V/sub g//V/sub s/, to obtain a unique pressure--temperature curve. Such pressure--temperature relationships were measured for three values of V/sub g//V/sub s/, each curve showing three points of discontinuous slope. For V/sub g//V/sub s/ = 1, the pressure exceeded 6000 psia above 487/sup 0/F. Since the Green River oil shale formation in Colorado contains both beds and isolated nodules of nahcolite, the pressure developed by heating nahcolite may be a factor in developing porosity and permeability during an in situ thermal process for producing shale oil.