Abstract: Based on a complete set of equipment of cryogenically separating LNG from syngas in the domestic project from coal to aromatics of 100 000 tons/year which was undertaken by Hangyang Limited, a liquefaction process with expander has been developed. Most of cold capacity was provided by using high-pressure nitrogen via the refrigeration circle of turbo expander by adiabatic expansion. Separation of synthesis gas and LNG liquefaction was achieved by using double column cryogenic distillation. When the gas was expanding in the expander, the power was output to drive the supercharger. Compared with the mixed refrigerant process, the liquefaction process with expander has advantages of compact layout, small occupation area, less refrigerant consumption (about 89%), low integrated operation cost, high safety, rapid start, as well as adapting to the varying load conditions from 70% to 110%. It has realized the nationalization of technique and equipment.