Processes for the separation of water from aqueous systems
Processes for the separation of water from a mixture of water with other components, comprising the following steps: A) providing feed material FM comprising water and at least one a nonionic surfactant S in an amount of 0.1 to 1000 ppm by weight based on the feed material FM, B) subjecting said feed material FM to a distillation step using a falling film evaporator.
1. A process for separating water from a mixture of water with at least one other component, the process comprising: providing a feed material comprising water and at least one nonionic surfactant in an amount of 0.1 to 1000 ppm by weight based on the feed material, and carrying out distillation of the feed material with a falling film evaporator, wherein the at least one nonionic surfactant is a polyalkylene oxide (PAO), wherein said PAO comprises a copolymer of at least two different types of alkylene oxides, and wherein said PAO is optionally functionalized at its terminal hydroxyl (OH) positions.
2. The process according to claim 1 , wherein the distillation is carried out as a multieffect distillation.
3. The process according to claim 1 , wherein the feed material further comprises at least one polymer A that is a polymer of at least one ethylenically unsaturated mono carboxylic acid and/or at least one ethylenically unsaturated dicarboxylic acid in an amount of 0.1 to 1000 ppm by weight based on the feed material.
4. The process according to claim 1 , wherein the feed material further comprises at least one polymer that is a block copolymer comprising at least one polyolefinic block and at least one polyalkylene oxide block in an amount of 0.01 to 100 ppm by weight based on the feed material.
5. The process according to claim 1 , wherein the feed material further comprises a nonionic surfactant selected from the group consisting of an alkoxylate of a linear or branched C 4 -C 26 alcohol and a block copolymer comprising blocks of polyethyleneoxide and polypropylene oxide.
6. The process according to claim 1 , wherein the nonionic surfactant has a molar mass of from 500 to 6000 g/mol.
7. The process according to claim 1 , wherein said nonionic surfactant has an ability to reduce a contact angle of water on a surface of a tube material by 1 to 40 degrees.
8. The process according to claim 7 , wherein the process is carried out as a multi effect distillation and wherein the tube material is selected from the group consisting of aluminum brass, titanium, stainless steel, an alloy of copper/nickel, an alloy of aluminum/magnesium, a metal comprising a ceramic coating, and a polymer composite comprising graphite and at least one organic polymer.
9. The process according to claim 1 , wherein the feed material is a solution of sugar, salt water, brackish water or brine obtained in at least one waste water treatment operation.
10. The process according to claim 1 , wherein the nonionic surfactant is a polyalkyleneoxide which has a structure PEO-PPO-PEO, PPO-PEO-PPO, PEO-PBO-PEO or PEO-pTHF-PEO.