Increasing rate of hydrogen permeation through pipes and vessel walls

Abstract

Hydrogen can enter in metal during corrosion processes or other industrial processes. Atomic hydrogen can diffuse through the metallic lattice because of its small size. Its interaction car result In various types of embrittlement. Therefore, efficient hydrogen removal is desirable. In this work, Hydrogen permeation was studied in carbon steel A-179 and Hastelloy C-276, which are commonly used as structural material for equipment in industry Diffusion of hydrogen was measured using gas phase permeation techniques. The effect of temperature on hydrogen transport has been investigated. The minimum temperature ranges that hydrogen can diffuse through these two metals were determined . It was found that the lowest temperature of hydrogen permeation through carbon steel is in the range of 90≤T ≤ 150 °C and 200≤ T ≤ 250 °C for hastelloy. Passive oxide films were allowed to form on the outside surface of tube used in the tests. In the permeation mechanism, the iron oxide films behave as a barrier to hydrogen transport. The effect of a catalyst covering the outside surface was studied. The metal was coated with palladium to compare the diffusion rate with and with and without the presence of palladium on the outside tube surface. A palladium coating on the external surface of carbon steel gives a higher hydrogen permeation rate whereas there is no noticeable effect on hydrogen permeation rate whereas there is no noticeable effect on hydrogen permeation rate through hastelloy.