Abstract: All sulfur compounds can be efficiently removed from natural gas that contains hydrogen sulfide and other sulfur compounds such as mercaptan without using physical absorption. The process comprises an absorption step of treating natural gas by means of a chemical absorption method using an amine-containing solution to mainly remove hydrogen sulfide and carbon dioxide, an adsorption step of flowing the natural gas from the absorption step through a packed bed of a molecular sieve to mainly remove mercaptan, a recovery step of recovering sulfur compounds by converting the hydrogen sulfide removed in the absorption step into sulfur by means of the Claus process, a regeneration step of desorbing the mercaptan adsorbed on the molecular sieve in the adsorption step using heated gas and a reaction step of converting the mercaptan in the regeneration exhaust gas exhausted from the regeneration step into hydrogen sulfide.

Abstract: All sulfur compounds can be efficiently removed from natural gas that contains hydrogen sulfide and other sulfur compounds such as mercaptan without using physical absorption. The process comprises an absorption step of treating natural gas by means of a chemical absorption method using an amine-containing solution to mainly remove hydrogen sulfide and carbon dioxide, an adsorption step of flowing the natural gas from the absorption step through a packed bed of a molecular sieve to mainly remove mercaptan, a recovery step of recovering sulfur compounds by converting the hydrogen sulfide removed in the absorption step into sulfur by means of the Claus process, a regeneration step of desorbing the mercaptan adsorbed on the molecular sieve in the adsorption step using heated gas and a reaction step of converting the mercaptan in the regeneration exhaust gas exhausted from the regeneration step into hydrogen sulfide.

Abstract: Provided is an improved refrigeration system for pre-cooling natural gas or cooling a mixed refrigerant for natural gas liquefaction in a propane refrigeration process widely used for the liquefaction of natural gas. The system comprises a plurality of plate-fin heat exchangers preferably arranged in a parallel relationship for passing a propane refrigerant as a vertical flow and pre-cooling natural gas or cooling a mixed refrigerant for liquefying natural gas, and a thermo siphon drum for the propane refrigerant consisting of a horizontally disposed, laterally elongated tank. Because the passages of the heat exchanger for the natural gas or the mixed refrigerant extend over their entire length in mutually separate relationship, even when the propane refrigerant, the natural gas or the mixed refrigerant is in both gas and liquid phases, a high efficiency of heat transfer can be attained, and the size of the heat exchanger can be reduced.