Cascaded axial-flow saltwater crystallization system and use method thereof

A cascaded axial-flow saltwater crystallization system, comprising a photothermal salt collection module (1) and a Fresnel salt collection module (2), wherein the photothermal salt collection module (1) and the Fresnel salt collection module (2) are fixedly disposed side by side on a support frame (4);

• wherein the photothermal salt collection module (1) comprises a first heat collection tube (101) and a reflector (102);
• the first heat collection tube (101) is fixedly disposed on the support frame (4), and the reflector (102) is fixedly disposed below the first heat collection tube (101);
• the reflector (102) is configured to, by focusing sunlight to irradiate the first heat collection tube (101), heat the first heat collection tube (101);
• the first heat collection tube (101) is internally provided with a first inner chamber (114) for accommodating saltwater and provided with a water inlet (103), a salt outlet (104), and a steam exhaust port (105), and the water inlet (103), the salt outlet (104), and the steam exhaust port (105) are connected to the first inner chamber (114);
• and
• wherein the Fresnel salt collection module (2) comprises a second heat collection tube (201) and a linear Fresnel convex lens (202);
• the second heat collection tube (201) is fixedly disposed on the support frame (4), and the linear Fresnel convex lens (202) is fixedly disposed above the second heat collection tube (201);
• and the linear Fresnel convex lens (202) is configured to, by focusing the sunlight to irradiate the second heat collection tube (201), heat the second heat collection tube (201);
• the second heat collection tube (201) is internally provided with a second inner chamber (212) and provided with a salt inlet (203) and a salt discharge port (204), the salt inlet (203) and the salt discharge port (204) are connected to the second inner chamber (212), and the salt outlet (104) is connected to the salt inlet (203).