Application Note: On-Line Gas Analysis In Hydrogen Plants

Emerson provides Rosemount Analytical gas analyzer technology for on-line analysis of hydrogen plant streams. Strategically placed gas analyzers improve the process efficiency and the purity of the end product.

Large quantities of hydrogen (H₂) are needed for refining crude oil into various products such as gasoline, jet fuel and heating oil. The largest refinery applications for H2 are the "upgrading" of crude oil in the hydrotreating and hydrocracking processes. Other uses of H₂ include production of chemicals such as ammonia, hydrochloric acid and methanol; as a reducing agent for metallic ores and also for hardening and heat treating of metals; as a hydrogenating agent for foods such as margarine and peanut butter; for cooling of electrical generators at power plants (because H₂ has the highest thermal conductivity of any gas); and for cryogenic research including superconductivity studies.

Hydrogen is primarily produced by reacting natural gas or methane (CH₄) with steam in a reformer. In the process of reforming natural gas or methane to hydrogen, carbon monoxide (CO) and carbon dioxide (CO₂) are formed as by-products. Even at low concentrations, both CO and CO₂ adversely affect catalysts in many refining and chemical processes. Therefore, to prevent downstream problems the removal and measurement of CO and CO₂ on a continuous basis is required before the hydrogen can be used in these processes.

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