Method for Purification of Oil and Gas Condensate from Hydrogen Sulfide and Mercaptans

Abstract

Hydrogen sulfide and mercaptans contained in oil or gas condensate after treatment with an aqueous solution containing formaldehyde, nitrogen-containing organic bases (primary and secondary amines, alkanolamines and urea), ammonia and caustic soda and / or sodium carbonate, with the formation of less toxic compounds. 0.8 - 10.0 mol of formaldehyde, 0.3 - 5.0 mol of a nitrogen-containing base, urea, ammonia or mixtures thereof and 0.001 - 0.05 wt. % NaOH and/or Na2CO3. The reagents were introduced in the form of aqueous solutions or as a pre-prepared mixture. To speed up the process, up to 1 mol of elemental sulfur per 1 mol of RSH and up to 0.1 nm3 of air per 1 mol of hydrogen sulfide and mercaptan sulfur were added.

This method made it possible to reduce the consumption of reagents with a high degree of purification of raw materials and energy costs. We used a more watered solution of reagents, the amount of this solution is much higher than the amount of a more concentrated solution, which led to an increase in the contact surface between the organic and aqueous phases in the emulsion; water-soluble, low molecular weight mercaptans and hydrogen sulfide to a greater extent pass into the aqueous phase, where they quickly react with formaldehyde.The combination of these factors made it possible to drastically reduce the required mixing time (the volume of the reactor decreases), reduce the reaction temperature and the cost of heating the feedstock, and carry out a deeper purification of the feedstock at the same reagent consumption or reduce the consumption of reagents.