Patent ID: 11946004
Assignee: ZHENHAI PETROCHEMICAL JIANAN ENGINEERING CO., LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC C  B  F | IPC B  C  F

Claim 8:
9. A heat exchange process for exchanging heat by using the atmospheric-vacuum heat exchange system of claim 8, wherein crude oil from the outside at a temperature of 20° C. to 60° C. is fed into a pipe (A) and then divided into two parts, a first-section crude oil I and a second-section crude oil II, the mass flow ratio of the first-section crude oil I to the second-section crude oil II is 1:0.8-1.2;
the first-section crude oil I firstly enters the shell passage of the first three-stream winding-tube heat exchanger (31) and exchanges heat to 80° C. to 110° C. with primary top oil gas from the top pipeline (41) of the primary distillation tower (4) or flash tower at a temperature of 100° C. to 140° C., atmospheric top circulating oil from the tube passage of the first single-stream winding-tube heat exchanger (11) at a temperature of 110° C. to 150° C. and atmospheric top oil gas from the first pipeline (68) on the top of the atmospheric tower (6) at a temperature of 100° C. to 150° C., the mass flow ratio of the first-section crude oil I to the atmospheric top oil gas to the atmospheric top circulating oil to the primary top oil gas being 1:0.1-0.3:0.25-0.4:0.06-0.2;
the first-section crude oil I from the first three-stream winding-tube heat exchanger (31) enters the shell passage of the second three-stream winding-tube heat exchanger (32) and exchanges heat to 120° C. to 155° C. with atmospheric third-line oil from the tube passage of the fourth three-stream winding-tube heat exchanger (34) at a temperature of 180° C. to 220° C., atmospheric second-line oil from the tube passage of the fourth three-stream winding-tube heat exchanger (34) at a temperature of 160° C. to 200° C. and atmospheric first-line oil from the tube passage of the second two-stream winding-tube heat exchanger (22) at a temperature of 130° C. to 170° C., the mass flow ratio of the first-section crude oil I to the atmospheric third-line oil to the atmospheric second-line oil to the atmospheric first-line oil is 1:0.1-0.3:0.1-0.3:0.15-0.35;
the second-section crude oil II firstly enters the shell passage of the third three-stream winding-tube heat exchanger (33) and exchanges heat to 80° C. to 110° C. with primary top oil gas from the top pipeline (41) of the primary distillation tower (4) or flash tower at a temperature of 100° C. to 140° C., atmospheric top circulating oil from the tube passage of the first single-stream winding-tube heat exchanger (11) at a temperature of 110° C. to 150° C. and atmospheric top oil gas from the first pipeline (68) on the top of the atmospheric tower (6) at a temperature of 100° C. to 150° C., the mass flow ratio of the second-section crude oil II to the atmospheric top oil gas to the atmospheric top circulating oil to the primary top oil gas is 1:0.1-0.3:0.25-0.4:0.06-0.2;
the second-section crude oil II from the third three-stream winding-tube heat exchanger (33) enters the shell passage of the first single-stream winding-tube heat exchanger (11) and exchanges heat to 100° C. to 130° C. with atmospheric top circulating oil from the second lateral line (67) in the upper portion of the atmospheric tower (6) at a temperature of 130° C. to 180° C., the mass flow ratio of the second-section crude oil II to the atmospheric top circulating oil being 1:0.5-0.8;
the second-section crude oil II from the first single-stream winding-tube heat exchanger (11) enters the shell passage of the first two-stream winding-tube heat exchanger (21) and exchanges heat to 120° C. to 150° C. from vacuum residues from the tube passage of the third two-stream winding-tube heat exchanger (23) at a temperature of 170° C. to 210° C. and vacuum second-line and second-medium oil from the tube passage of the fourth two-stream winding-tube heat exchanger (24) at a temperature of 145° C. to 185° C., the mass flow ratio of the second-section crude oil II to the vacuum residues to the vacuum second-line and second-medium oil being 1:0.5-0.7:0.9-1.3; and
the first-section crude oil I from the shell passage of the second three-stream winding-tube heat exchanger (32) and the second-section oil from the shell passage of the first two-stream winding-tube heat exchanger (21) are merged into one stream of crude oil at a temperature of 120° C. to 150° C. and then enter the electric desalting unit (9) so that salt and water in the crude oil are removed;
the desalted crude oil from the electric desalting unit (9) has a temperature of 120° C. to 150° C., and the mass flow ratio of the merged crude oil before entering the electric desalting unit (9) and the desalted crude oil is 1:0.95-1.05;
the desalted crude oil is divided into two parts, a first desalted crude oil I and a second desalted crude oil II, the flow mass ratio of the first desalted crude oil I to the second desalted crude oil II is 1:0.8-1.2;
the first desalted crude oil I firstly enters the shell passage of the second two-stream winding-tube heat exchanger (22) and exchanges heat to 145° C. to 185° C. with atmospheric first-line oil from the first lateral line (66) in the middle portion of the atmospheric stripping tower (64) at a temperature of 170° C. to 210° C. and atmospheric first-medium oil from the first circulating return pipeline (62) in the middle portion of the atmospheric tower (6) at a temperature of 210° C. to 250° C., the mass flow ratio of the first desalted crude oil I to the atmospheric first-line oil to the atmospheric first-medium oil is 1:0.1-0.3:0.2-0.4;
the first desalted crude oil I from the second two-stream winding-tube heat exchanger (22) enters the shell passage of the third two-stream winding-tube heat exchanger (23) and exchanges heat to 190° C. to 250° C. with vacuum residues from the tube passage of the fifth three-stream winding-tube heat exchanger (35) at a temperature of 265° C. to 305° C. and returned vacuum residues from the tube passage of the fifth three-stream winding-tube heat exchanger (35) at a temperature of 265° C. to 305° C., the mass flow ratio of the first desalted crude oil I to the returned vacuum residues to the vacuum residues is 1:0.35-0.6:0.05-0.2;
the second desalted crude oil II firstly enters the shell passage of the fourth two-stream winding-tube heat exchanger (24) and exchanges heat to 140° C. to 180° C. with vacuum second-line and second-medium oil from the tube passage of the fourth three-stream winding-tube heat exchanger (34) at a temperature of 160° C. to 200° C. and vacuum third-line and third-medium oil from the tube passage of the fifth two-stream winding-tube heat exchanger (25) at a temperature of 220° C. to 265° C., the mass flow ratio of the second desalted crude oil II to the vacuum second-line and second-medium oil to the vacuum third-line and third-medium oil is 1:0.9-1.3:0.05-0.2;
the second desalted crude oil II from the fourth two-stream winding-tube heat exchanger (24) enters the shell passage of the fourth three-stream winding-tube heat exchanger (34) and exchanges heat to 200° C. to 250° C. with atmospheric second-line oil from the second pipeline (65) on the bottom of the atmospheric stripping tower (64) at a temperature of 240° C. to 280° C., atmospheric third-line oil from the tube passage of the fifth three-stream winding-tube heat exchanger (35) at a temperature of 275° C. to 315° C. and vacuum second-line and second-medium oil from the fourth circulating return pipeline (82) in the middle portion of the vacuum tower (8) at a temperature of 230° C. to 270° C., the mass flow ratio of the second desalted crude oil II to the atmospheric second-line oil to the atmospheric third-line oil to the vacuum second-line and second-medium oil is 1:0.1-0.3:0.1-0.3:0.9-1.3; and
the first desalted crude oil I from the shell passage of the third two-stream winding-tube heat exchanger (23) and the second desalted crude oil II from the shell passage of the fourth three-stream winding-tube heat exchanger (34) are merged into one stream of desalted crude oil and then enter the primary distillation tower (4) or flash tower for preliminary fractionation;
primary bottom oil or flash bottom oil at a temperature of 200° C. to 250° C. is extracted from the bottom of the primary distillation tower (4) or flash tower, and the mass flow ratio of the merged desalted crude oil to the primary bottom oil or flash bottom oil is 1:1.6-1.95;
the primary bottom oil or flash bottom oil firstly enters the shell passage of the fifth two-stream winding-tube heat exchanger (25) and exchanges heat to 250° C. to 280° C. with vacuum third-line and third-medium oil from the tube passage of the fifth three-stream winding-tube heat exchanger (35) at a temperature of 260° C. to 300° C. and atmospheric second-medium oil from the second circulating return pipeline (61) in the middle portion of the atmospheric tower (6) at a temperature of 260° C. to 300° C., the mass flow ratio of the primary bottom oil or flash bottom oil to the vacuum third-line and third-medium oil to the atmospheric second-medium oil is 1:0.3-0.6:0.5-0.7;
the primary bottom oil or flash bottom oil from the fifth two-stream winding-tube heat exchanger (25) enters the shell passage of the fifth three-stream winding-tube heat exchanger (35) and exchanges heat to 280° C. to 320° C. with vacuum third-line and third-medium oil from the third circulating return pipeline (81) in the lower portion of the vacuum tower (8) at a temperature of 310° C. to 350° C., vacuum residues from the tube passage of the second single-stream winding-tube heat exchanger (12) at a temperature of 300° C. to 340° C. and atmospheric third-line oil from the third lateral line (63) in the middle portion of the atmospheric tower (6) at a temperature of 300° C. to 340° C., the mass flow ratio of the primary bottom oil or flash bottom oil to the vacuum third-line and third-medium oil to the vacuum residues to the atmospheric third-line oil is 1:0.3-0.6:0.25-0.45:0.05-0.15; and
the primary bottom oil or flash bottom oil from the fifth three-stream winding-tube heat exchanger (35) enters the shell passage of the second single-stream winding-tube heat exchanger (12) and exchanges heat to 300° C. to 330° C. with vacuum residues from the vacuum residue pipeline (83) on the bottom of the vacuum tower (8) at a temperature of 350° C. to 400° C., the mass flow ratio of the primary bottom oil or flash bottom oil to the vacuum residues is 1:0.25-0.45; and
the primary bottom oil or flash bottom oil from the shell passage of the second single-stream winding-tube heat exchanger (12) is successively delivered to the atmospheric furnace (5), the atmospheric tower (6), the vacuum furnace (7) and the vacuum tower (8) for atmospheric and vacuum heat exchange.