Cascade connecting type liquidizing system of base load type natural gas liquefaction factories

The invention discloses a cascade connecting type liquidizing system of base load type natural gas liquefaction factories, belongs to natural gas liquefaction technology field. The liquidizing system comprises a propane heat exchanger, an ethane heat exchanger, a methane heat exchanger, a nitrogen gas heat exchanger, a propane precooling circulating mechanism, an ethane refrigerating circulating mechanism, a methane copious cooling circulating mechanism and a nitrogen gas copious cooling circulating mechanism. The system has the following benefits: (1) having the advantage in the traditional hierarchical technology that mixed cryogen is not needed to be composed, and meanwhile combining the advantage of the mixed cryogen; (2) making for balancing heat exchange load of the sections during the precooling, the liquidizing and the undercooling processes of natural gas, and making for the equipment manufacturing and plate-fin heat exchanger application; (3) balancing the load of compressors in the sections, improving single line manufacturing scale, and making for expanding the manufacturing scale.