Water desalination installation

A water desalination installation for desalinating seawater according to the reverse osmosis method, comprising at least one membrane module (1) connected with a raw water feed line (2), via which raw water is supplied by means of a high-pressure pump (3);

• a permeate line (5), via which the desalinated water is discharged;
• and a concentrate line (6), via which concentrated salt water is discharged, an energy recovery unit (8) comprising a pressure booster pump (9) arranged in the raw water feed line (2) either before the high-pressure pump (3) or between the high-pressure pump (3) and the membrane module (1);
• and a first turbine (11) arranged in the concentrate line (6) and mechanically coupled with the pressure booster pump (9);
• whereby provision is made in the concentrate line (6) between the membrane module (1) and the energy recovery unit (8) for a branch (14), via which concentrated salt water can be supplied to a second turbine (15) mechanically coupled with the high-pressure pump (3);
• and whereby provision is made between the branch (14) and the second turbine (15) for a throttling valve (16).

A water desalination installation for the desalination of seawater according to the reverse osmosis method, comprising a first membrane module (18) connected with a raw water feed line (19), via which raw water is supplied by means of a high-pressure pump (20);

• a first permeate line (21), via which desalinated water is discharged;
• a first concentrate line (22), via which concentrated salt water is discharged from the first membrane module (18);
• and a second membrane module (23), which is supplied with concentrated, salt water by way of the first concentrate line (22), whereby the second membrane module (23) is connected with a second permeate line (24), via which desalinated water is discharged, and with a second concentrate line (25), via which concentrated salt water is discharged, a pressure booster pump (26) being arranged in the first concentrate line (22) between the first and the second membrane modules, and by a. first turbine (28), said turbine being arranged in the second concentrate line (25) and mechanically coupled with the pressure booster pump (26);
• whereby provision is made in the second concentrate line (25) between the second membrane module (23) and the first turbine (28) for a branch (29), via which concentrated salt water can be supplied to a second turbine (31), the latter being mechanically coupled with the high-pressure pump (20);
• and whereby provision is made between the branch (29) and the second turbine (31) for a throttling valve (30).