High-Efficiency Catalytic Oxidation Technology for Tight-Gas Flash Gas Based on High-Activity Catalysts and an Integrated Reactor

PetroChina Southwest Oil & Gas Field Company Tight Oil and Gas Exploration and Development Project Department, China

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Abstract

The exhaust gas emitted from atmospheric flash tanks in tight gas fields contains large quantities of volatile organic compounds (VOCs) and methane, causing atmospheric pollution. Effective treatment is therefore urgently required to achieve compliant emissions. After a comparative analysis of various VOCs treatment technologies, catalytic oxidation was selected. Because flash gas is composed mainly of methane and low-chain alkanes, whereas conventional transition-metal catalysts or catalysts with low precious-metal contents show relatively low conversion efficiencies for such components, this study focused on the effects of Pt/Pd precious-metal loading and space velocity on conversion efficiency and reaction temperature rise, and optimized the catalytic furnace structure to achieve effective temperature-rise control. When the precious-metal content in the catalyst exceeded 3 kg/m³, the methane conversion efficiency exceeded 98.5% at an ignition temperature of 390 °C. Meanwhile, owing to the high heat release during catalytic oxidation, dilution with 180 volumes of air, combined with in-furnace heat-recovery design, effectively controlled the maximum temperature of the catalytic furnace within 450 C. Increasing the Pt/Pd precious-metal loading in the catalyst can effectively solve the difficulty of removing VOCs and methane from flash gas; controlling the amount of supplemental air can effectively suppress reaction temperature rise; and coupling these measures with a novel catalytic oxidation furnace structure featuring heat recovery enables the efficient, stable, and safe treatment of atmospheric flash-gas exhaust in tight gas fields.