Regeneration of alkali metal reagent

A method for regenerating an alkali metal salt reagent, comprising:

• a) receiving a hydrocarbon feedstream having an API gravity of at least about 20, the hydrocarbon feedstream including at least about 7.5 wt % of alkali metal salt particles, the alkali metal salt particles comprising alkali hydrogen sulfide particles;
• b) washing the hydrocarbon feedstream with water to form a hydrocarbon product stream and an aqueous stream containing alkali metal salt;
• c) splitting the aqueous stream comprising alkali metal salt into a first portion and a second portion;
• d) treating the first portion of the aqueous alkali metal salt stream with carbon dioxide under effective conditions to form aqueous alkali carbonate;
• e) mixing the aqueous alkali carbonate with calcium oxide under effective conditions to form alkali hydroxide and calcium carbonate solids;
• f) separating the calcium carbonate from the aqueous alkali hydroxide;
• g) combining the second portion of aqueous alkali metal salt with the aqueous alkali hydroxide;
• h) dehydrating the combined aqueous alkali metal salt and aqueous alkali metal hydroxide to form alkali metal sulfide;
• and
• i) heating the calcium carbonate under effective conditions to form regenerated calcium oxide, wherein at least a portion of the regenerated calcium oxide is used for said mixing with aqueous alkali carbonate.