Process for producing ultra-pure water and process for using said ultra-pure water

• US 4,879,041 A
• Filed: 03/24/1988
• Issued: 11/07/1989
• Est. Priority Date: 03/25/1987
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yoda, Hiroaki, Okouchi, Isao, Yamada, Akira, Momma, Naohiro, Hishinuma, Yukio, Matsuzaki, Harumi, Koseki, Yasuo, Kurokawa, Hideaki, Ebara, Katsuya, Hayashi, Nobuatsu, Takahashi, Sankichi
• Primary Examiner(s): Sever, Frank
• Application Number:
  US07/172,583
• Time in Patent Office: 593 Days
• Field of Search: 55/158, 202/200, 159/DIG. 27, 20/640, 20/192, 203/DIG. 17, 203/DIG. 24, 203/DIG. 11
• US Class Current: 210/640
• CPC Class Codes: B01D 3/06 Flash distillation
• CPC Class Codes: B01D 61/364 Membrane distillation
• CPC Class Codes: C02F 1/045 for obtaining ultra-pure water
• CPC Class Codes: Y10S 210/90 Ultra pure water, e.g. conductivity water

Abstract

The present invention relates to a process for producing ultra-pure water, an apparatus for producing said ultra-pure water and a process for using the ultra-pure water produced according to said process. More particularly, the present invention relates to a process for producing ultra-pure water which comprises boiling a raw water to vaporize off the volatile components from the raw water, subsequently generating steam from the water, contacting the steam with a hydrophobic, porous, gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane, and then condensing the steam, as well as to an apparatus for producing said ultra-pure water and a process for using said ultra-pure water.

Claims

1. A process for producing ultra-pure water which comprises boiling raw water to vaporize off volatile components from the raw water, subsequently generating steam from the boiled water from which said volatile components have previously been removed, contacting the steam with a hydrophobic, porous, gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, and then condensing the steam to form ultra-pure water.

2. A process for producing ultra-pure water which comprises boiling raw water to vaporize off volatile components from the raw water, subsequently generating steam from the boiled water from which said volatile components have previously been removed, contacting the steam with a hydrophobic, porous, gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, leading the steam having permeated the membrane into an atmosphere of saturated steam or inert gas, and condensing the steam in said atmosphere to form ultra-pure water.

3. A process for producing ultra-pure water by generating steam from raw water, making the steam permeate a hydrophobic, porous, gas-permeable and liquid-impermeable membrane removing liquid mist sufficient to produce high purity steam substantially free of impurities, and then condensing the steam, which comprises a step for heating and boiling the raw water to vaporize off volatile components and a step for generating steam from the raw water from which said volatile components been removed by having completed the preceding step and contacting the steam with said hydrophobic porous membrane to form ultra-pure water.

4. A process for producing ultra-pure water by generating steam from raw water, making the steam permeate a hydrophobic, porous, gas-permeable and liquid impermeable membrane removing liquid mist sufficient to produce high purity steam substantially free of impurities, and then condensing the steam;

which comprises a step for boiling the raw water to vaporize off volatile components while keeping the raw water under a reduced pressure and a step for generating steam from the raw water from which said volatile components have been removed by having completed the preceding step and contacting the steam with said hydrophobic porous membrane to form ultra-pure water.

5. A process for producing ultra-pure water which comprises boiling a raw water containing volatile components and nonvolatile components to vaporize off the volatile components, subsequently generating steam from the boiled raw water from which said volatile components have previously been removed, contacting only the steam with a hydrophobic, porous, gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, and then condensing the steam to form ultra-pure water.

6. A process for producing ultra-pure water which comprises boiling a raw water containing volatile components and nonvolatile components to vaporize off the volatile components, subsequently heating the boiled raw water from which said volatile components have previously been removed to generate steam, contacting only the steam with a hydrophobic, porous, gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, leading the steam having permeated the membrane into an atmosphere of saturated steam or inert gas, and condensing the steam in said atmosphere to form ultra-pure water.

7. A process for producing ultra-pure water which comprises heating a raw water containing volatile and volatile and nonvolatile components to vaporize off the volatile components, subsequently again heating the raw water from which said volatile components have previously been removed to generate steam, contacting only the steam with a hydrophobic porous gas-permeable and liquid-impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, and then condensing the steam to provide ultra-pure water to form ultra-pure water.

8. A process for producing ultra-pure water which comprises heating and boiling a raw water containing volatile components and nonvolatile components to vaporize off the volatile components, subsequently again heating the raw water from which said volatile components have previously been removed to generate steam, contacting only the steam with a hydrophobic, porous, gas-permeable and liquid permeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, leading the steam having permeated the membrane into an atmosphere of saturated steam or inert gas, and then condensing the steam in said atmosphere to form ultra-pure water.

9. A process for producing ultra-pure water which comprises a step for heating and boiling a raw water containing volatile components and nonvolatile components to vaporize off the volatile components and a subsequent step for again heating the raw water from which said volatile components have previously been removed to generate steam by using a steam containing the vaporized volatile components obtained in the preceding step as a heat source, contacting only the generated steam with a hydrophobic, porous, gas-permeable and liquid impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities and then condensing the steam to form ultra-pure water.

10. A process for producing ultra-pure water which comprises a step for heating and boiling a raw water containing volatile components and nonvolatile components to vaporize off the volatile components and a subsequent step for again heating the raw water from which said volatile components have previously been removed to generate steam by using a steam containing the vaporized volatile components formed in the preceding step as a heat source, contacting only the generated steam with a hydrophobic, porous, gas-permeable and liquid impermeable membrane to make the steam permeate the membrane and removing liquid mist sufficient to produce a high purity steam substantially free of impurities, leading the steam having permeated the membrane into an atmosphere of saturated steam or inert gas and condensing the steam in said atmosphere to form ultra-pure water.

11. A process for producing ultra-pure water which comprises generating steam from a raw water previously freed of volatile components by heating outside of a clean room for isolating the used point of ultra-pure water of the outer atmosphere, subsequently transporting the generated steam into the clean room in a gaseous state and condensing it by means of a condenser provided in the neighborhood of the used point and equipped with a hydrophobic porous membrane for removing liquid mist from said steam to provide ultra-pure water.

12. A process for producing ultra-pure water according to claim 11, wherein steam is generated from raw water after removing carbon dioxide gas and organic substances from the raw water.

13. A process for producing ultra-pure water comprising:

heating raw water containing impurities to vaporize off volatile components from the raw water;

heating the raw water from which the volatile components have previously been removed to generate steam;

passing said steam through a hydrophobic porous membrane to remove water droplets from said steam, and to produce high purity steam being substantially free of said impurities; and

condensing said high purity steam to obtain ultra-pure water.

14. A process according to claim 13, wherein said step of condensing is carried out in an atmosphere of saturated steam or inert gas.

15. A process according to claim 13, wherein said ultra-pure water has a specific resistance of 18 MΩ

-cm or above, fine particles with a size of 0.1 μ

m or more in an amount of 100 particles/liter or, less, 10 microorganisms/liter or less, and 10 ppb or less of organic substances.