Thermal desalination for increased distillate production

Patent metadata

Field	Value
Publication number	US-10508043-B2
Application number	US-201414576798-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 20, 2013
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A superstructure for thermal desalination is optimized by controlling various parameters, wherein the variable parameters include a feed routing for flow of a liquid feed; brine routings for flow of concentrated brine from the liquid feed; vapor routings for vapor generated from the liquid feed; a series of multi-effect distillation effects, each of the effects coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings; and a series of multi-stage flash stages coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings. The superstructure may or may not contain a thermal vapor compressor.

First claim

What is claimed is:

1. A method for thermal-based desalination, comprising a feed routing including a series of preheaters for flow of a liquid feed; brine routings for flow of concentrated brine from the liquid feed; vapor routings for vapor generated from the liquid feed; a series of multi-effect distillation effects, each of the effects coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings; and a series of brine flash boxes coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings, the method comprising:
flowing a liquid feed through the feed routing and using the preheaters to heat the liquid feed in the feed routing;
using at least one of a plurality of splitters between preheaters to selectively direct at least one of (a) a first portion of the flow of the liquid feed from the feed routing through at least one of the multi-effect distillation effects in the series of multi-effect distillation effects and (b) a second portion of the flow of the liquid feed through a subsequent preheater in the series of preheaters, and to shift allocation of the flow between the first portion and the second portion, wherein the first portion of the liquid feed flows into an inlet of a first effect, where the feed liquid is heated to produce vapor that is directed through at least one of the vapor routings and brine that is directed through at least one of the brine routings;
flowing a first part of the vapor produced in at least one effect from one of the vapor routings through at least one of the preheaters to transfer heat from the vapor to the liquid feed in the feed routing;
flowing a second part of the vapor produced in the at least one effect from another of the vapor routings to a subsequent effect in the series;
flowing brine produced in each effect from at least one of the brine routings through a brine flash box and heating the brine to release additional vapor and produce a concentrated brine that is directed through another of the brine routings; and
using additional splitters, each of which is downstream of a flash box in the series of brine flash boxes in at least one of the brine routings, to selectively direct the concentrated brine from each flash box into at least one of (a) a first stream that is directed through one of the brine routings to another flash box in the series of brine flash boxes and (b) a second stream that is directed through another of the brine routings into another effect.

2. The method of claim 1 , further comprising adjusting flow through the feed, brine, and vapor routings to achieve at least one result selected from (a) increasing the performance ratio of distillate production; (b) decreasing specific heat transfer area requirements; (c) increasing recovery ratio; and (d) increasing gained output ratio.

3. The method of claim 2 , further comprising:
extracting liquid feed at locations between different pairs of preheaters; and
injecting the extractions of liquid feed into respective multi-effect distillation effects.

4. The method of claim 3 , further comprising blending brine that exits a brine flash box with feed liquid fed to a multi-effect distillation effect.

5. The method of claim 4 , further comprising changing at least one of the following parameters to achieve at least one of the results: (a) positions between preheaters at which liquid feed is extracted from the feed routing; (b) the flow of concentrated brine through the brine routings to change which brine flash box feeds concentrated brine to a particular effect among the series of multi-effect distillation effects; (c) sizing of at least one of the routings, brine flash boxes, multi-effect distillation effects, or preheaters; and (d) pressure in at least one of the multi-effect distillation effects or brine flash boxes.

6. The method of claim 5 , wherein the parameter is changed in response to changes in local operating conditions.

7. The method of claim 1 , further comprising:
injecting vapor into a thermal vapor compressor;
compressing steam in the thermal vapor compressor; and
delivering the compressed steam to at least one of the multi-effect distillation effects.

8. The method of claim of claim 1 , further comprising:
directing the vapor from the subsequent effect in the series to a down condenser;
directing the liquid feed through the down condenser; and
condensing the vapor in the down condenser.

9. The method of claim 8 , further comprising flowing vapor from the series of brine flash boxes through the down condenser.

10. The method of claim 1 , further comprising flowing vapor from the preheaters through a series of distillate flash boxes.

11. The method of claim 1 , further comprising flowing the brine sequentially through the series of brine flash boxes.

12. A method for producing an improved thermal-based desalination system, comprising providing a superstructure which comprises a feed routing including a series of preheaters for flow of a liquid feed; brine routings for flow of concentrated brine from the liquid feed; vapor routings for vapor generated from the liquid feed; a series of multi-effect distillation effects, each of the effects coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings for removal of vapor generated in the effect; a series of brine flash boxes coupled with at least one routing selected from the feed routing and the brine routings and with one of the vapor routings for removal of vapor generated in the brine flash box; splitters positioned between the preheaters and configured to split the flow of the liquid feed to selectively direct at least one of (a) a first portion of the flow of the liquid feed from the feed routing through at least one of the multi-effect distillation effects and (b) a second portion of the flow of the liquid feed through a subsequent preheater in the series of preheaters, and to shift allocation of the flow between the first portion and the second portion; and additional splitters, each of which is downstream of a flash box in the series of brine flash boxes in at least one of the brine routings, wherein the additional splitters are configured to selectively direct concentrated brine from each flash box into at least one of (a) a first stream that is directed through one of the brine routings to another flash box in the series of flash boxes and (b) a second stream that is directed through another of the brine routings into another effect, and to shift allocation of flow between the first stream and the second stream, the method comprising:
testing or simulating a variety of configurations of routings, preheaters, multi-effect distillation effects, and brine flash boxes by controlling the allocations of flow established by the splitters;
evaluating at least one property selected from (a) performance ratio of distillate production in said superstructure; (b) specific heat transfer area requirements in the superstructure; (c) recovery ratio; and (d) gained output ratio for each configuration;
reiterating the testing or simulating of different configurations to produce a superstructure in which the property is optimized;
configuring the splitters to establish feed routings through the series of preheaters and through the brine routings that match the optimized superstructure; and
flowing liquid feed through the feed routings that match the optimized superstructure.

13. The method of claim 12 , wherein the produced system further includes a thermal vapor compressor coupled with a vapor routing, the

Assignees

• Massachusetts Inst Technology
• Rheinisch Westfaelische Technische Hochschule Aachen

Inventors

• Dahdah Tawfiq Hanna
• Mitsos Alexander

Classifications

• C02F1/041

  by means of vapour compression · CPC title

• C02F2301/08

  Multistage treatments, e.g. repetition of the same process step under different conditions · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F1/06 Primary

  Flash evaporation · CPC title

• B01D3/146

  Multiple effect distillation · CPC title