METHODS AND SYSTEMS FOR ENHANCING COOLING POND PERFORMANCE AND SALT PRODUCTION IN A SOLUTION MINING OPERATION
20210402316 · 2021-12-30
Inventors
- Kathlene Laurie Jacobson (Saskatoon, CA)
- Grant Shaver (Regina, CA)
- Rubeena Batta (Regina, CA)
- Carey Heinbigner (Moose Jaw, CA)
- Murray Schultz (Regina, CA)
Cpc classification
B01D21/245
PERFORMING OPERATIONS; TRANSPORTING
B01D21/24
PERFORMING OPERATIONS; TRANSPORTING
B01D21/2488
PERFORMING OPERATIONS; TRANSPORTING
International classification
B01D21/24
PERFORMING OPERATIONS; TRANSPORTING
C01D3/06
CHEMISTRY; METALLURGY
Abstract
A cooling pond system and related methods of improving cooling performance in a cooling pond system using one or more submerged dams to increase cooling performance within the cooling pond system, and increase salt precipitation or recovery. The inclusion of one or more submerged dams within an existing cooling pond system can reduce an outflow temperature by 1-5° F. as compared to the same cooling pond system without any submerged dams. In addition or alternatively, pond depth can be controlled to enhance flow mixing and convection cooling. As the temperature is reduced throughout the cooling pond system, more potassium containing salts are precipitated form the brine solution resulting in increased production or recovery within the same cooling footprint.
Claims
1. A cooling pond system, comprising: at least one cooling pond, the cooling pond having a brine inlet stream and an outlet stream, the cooling pond defining a pond length, a pond width and a pond depth; and at least one submerged dam positioned across at least a portion of the pond width, the at least one submerged dam having an upper dam surface located below a pond surface.
2. The cooling pond system of claim 1, wherein the at least one submerged dam extends fully across the pond width.
3. The cooling pond system of claim 1, wherein the at least one submerged dam extends only across a portion of the pond width, said at least one submerged dam defining a dam opening.
4. The cooling pond system of claim 1, wherein the upper dam surface is positioned below the pond surface at a depth of about 1 foot to about 5 feet in depth.
5. The cooling ponds system of claim 1, wherein the pond is filled with a brine solution, said brine solution wherein a more concentrated brine layer resides proximate a pond floor, and wherein the at least one submerged dam causes an increase in the Reynolds number or vertical mixing of the brine solution such that the more concentrated brine layer is forced to the pond surface.
6. The cooling pond system of claim 1, wherein the at least one cooling pond includes at least an upstream cooling pond and a downstream cooling pond.
7. The cooling system of claim 6, wherein the upstream cooling pond includes at least one submerged dam and the downstream cooling pond includes at least one submerged dam.
8. The cooling pond system of claim 7, wherein the at least one submerged dam in the upstream cooling pond has a submerged depth from about 3 feet to about 5 feet.
9. The cooling pond system of claim 8, wherein the at least one submerged dam in the downstream cooling pond has a submerged depth from about 1 foot to about 4 feet.
10. A method for increasing cooling performance in a cooling pond system, comprising: supplying a brine feed stream to a cooling pond system; and forming one or more submerged dams within the cooling ponds system to increase turbulence or vertical mixing within the cooling pond system.
11. The method of claim 10, wherein forming one or more submerged dams, further comprises: dredging a precipitate layer in the cooling pond system to define the one or more submerged dams.
12. The method of claim 10, wherein forming one or more submerged dams, further comprises: spraying a slurry stream into the cooling pond system to define the one or more submerged dams.
13. The method of claim 10, wherein forming one or more submerged dams, further comprises: forming an upstream submerged dam; and forming a downstream submerged dam.
14. The method of claim 13, wherein the upstream submerged dam has a submerged depth from about 5 feet to about 3 feet below a pond surface.
15. The method of claim 14, wherein the downstream submerged dam has a submerged depth from about 3 feet to about 1 foot below a pond surface.
16. A method for increasing salt recovery in a cooling pond system, comprising: increasing a Reynolds number of a brine flow stream within one or more cooling ponds to increase convective cooling of the brine flow stream, thereby increasing salt precipitation from the brine stream.
17. The method of claim 16, wherein each of the one or more cooling ponds has a precipitated salt layer formed on a bottom surface of the pond, and a volume of brine solution over the precipitated salt layer, wherein a pond depth is measured from a top surface of the precipitated salt layer to a top surface of the brine solution, wherein increasing the Reynolds number comprises: actively controlling the pond depth within the one or more cooling ponds to optimize cooling of the brine flow stream through the cooling pond system.
18. The method of claim 17, wherein controlling the pond depth comprises: decreasing the pond depth within the one or more cooling ponds.
19. The method of claim 18, wherein the pond depth is decreased from 9.0 feet to 6.5 feet.
20. The method of claim 19, wherein the pond depth is decreased to 5.0 feet.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Various embodiment of the invention are now described by way of example to further the understanding of the present disclosure, with reference to the accompanying drawings in which:
[0018]
[0019]
[0020]
[0021]
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[0023]
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[0028]
[0029] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE DRAWINGS
[0030] Embodiments of the present disclosure relate generally to cooling pond systems for use with a source of salt solution or brine, such as, for example, from solution mining, a body of salt water, a crystallizer circuit or return stream, or any other suitable source of salt water in which salt recovery is desired. More specifically, the embodiments are directed to placing one or more submerged dams and/or to adjusting cooling pond depth. The pond depth and cooling dam systems, used alone or in combination, enhance surface convection of the ponds and/or control flow mixing, thereby increasing salt production.
[0031] Cooling Dams Referring now to
[0032] As seen in
[0033] Referring now to
[0034] In its simplest form, cooling pond 100 operates by having brine inlet stream 110 enter the lined pond 102 at upstream end 108 as shown in
[0035] In order to maximize cooling, one or more submerged dams 120 are formed across the pond width 106. Generally, the submerged dams 120 disrupt the brine stratification levels by increasing the Reynolds number of the brine inlet stream 110 as is reaches the submerged dam 120, thus increasing turbulence and mixing of the brine solution 146. By increasing turbulence and mixing, the denser brine solution 148, which is consequently at a higher temperature than the less dense brine solution 150, is vertically mixed and encouraged to rise to the pond surface 130. Due to the increase temperature differential between the ambient air and denser brine solution 148, the cooling rate is increased for the brine solution 146. With the increased cooling rate for brine solution 146, the solubility limit of the brine solution 146 is further decreased resulting in increased precipitation of the potassium containing salts.
[0036] Referring now to
[0037] As seen in
[0038] As seen in
[0039] Submerged dams 120 can generally be formed in a variety of ways. For instance, cooling pond 100 can have a precipitate layer 300 that has been deposited and accumulated on pond floor 132 as shown in
[0040] Referring now to
TABLE-US-00001 TABLE 1 Scenario Submerged Dams Configuration of Submerged Dams 1 No N/A 2 Yes Pond 402: (3) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 403: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 404: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 405: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 406: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 407: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 408: (2) submerged dams, 100 foot dam length, 4 foot submerged depth Pond 409: (3) submerged dams, 100 foot dam length, 4 foot submerged depth 3 Yes Pond 402: (3) submerged dams, 100 foot dam length, 3 foot submerged depth Pond 403: (2) submerged dams, 100 foot dam length, 3 foot submerged depth Pond 404: (2) submerged dams, 100 foot dam length, 1 foot submerged depth Pond 405: (2) submerged dams, 100 foot dam length, 1 foot submerged depth Pond 406: (2) submerged dams, 100 foot dam length, 1 foot submerged depth Pond 407: (2) submerged dams, 100 foot dam length, 1 foot submerged depth Pond 408: (2) submerged dams, 100 foot dam length, 3 foot submerged depth Pond 409: (3) submerged dams, 100 foot dam length, 3 foot submerged depth * For each scenario, the characteristics ncluding flow rate, temperature and brine solution concentration for brine inlet stream 420 and recycle stream 422. In Scenarios 2 and 3, the submerged dams 120 each had full width construction. Furthermore, ambient temperature air temperature and wind speeds were maintained between the scenarios. Each pond has a pond depth 134 of 9 feet.
[0041] The cooling performance and consequently, production increase percentage (precipitate production) for Scenarios 2 and 3 as compared to Baseline Scenario 1 are summarized in Table 2 below:
TABLE-US-00002 TABLE 2 Scenario Outlet Stream 424 Production Temperature (° F) Increase (% gain) 1 31.6 N/A 2 28.7 5.3% 3 28.0 8.1%
[0042] As illustrated in Tables 1 and 2, the use of submerged dams 120 within cooling pond systems increases the cooling capacity of the cooling pond system and results in an increase in the amount of potassium containing salts recovered from the cooling ponds system. Furthermore, the construction of submerged dams 120 having a reduced submerged depth can further increase cooling production and product recovery. However, the submerged depth must be compared to other operational conditions including dredging capacity and product capacity to determine the best design for submerged dams 120 within any particular cooling pond system.
Pond Depth
[0043] Referring now to
[0044] Referring now to
[0045] In its simplest form, and as described above with respect to the cooling dam embodiments, cooling pond 1000 operates by having brine inlet stream 1010 enters the lined pond 1002 at upstream end 1008 as shown in
[0046] In order to enhance the cooling performance of the cooling pond 1000, increased mixing between the stratified layers, or the denser brine solution 1046a proximate the top 1049 of floor 1048 and less concentrated or less dense brine solution 1046b proximate the pond surface 1030 can be promoted. Mixing can be increased to increase the Reynolds number such that flow within the cooling pond 1000 is more turbulent, which in turn results in increased heat loss by convection. One method of increasing the Reynolds number can involve increasing the flow velocity of the brine solution 1046 through the cooling pond 1000. With a cooling pond 1000 that has a fixed pond width 1006, velocity of the brine solution 1046 can be increased by decreasing the pond depth 1034 while maintaining the volume of the brine inlet stream 1010 and the brine outlet stream 1012.
[0047] In an actual processing environment, a cooling pond system 1050 for the precipitation of potassium containing salts typically involves a plurality of interlinked cooling ponds 1000 as shown in
[0048] In one particular embodiment, depicted in
[0049] The effects of different pond depths 1034 are demonstrated further in the non-limiting examples set forth below.
Example 1
[0050] In a first example, cooling pond system 1050 was modeled with cooling ponds 1051, 1052, 1053, 1054, 1055, 1056, 1057, 1058, 1059, 1060, and 1061 having pond depths 1034 of 9 feet, 6.5 feet and 5 feet. For purposes of the model, an effective pond depth 1034 was assumed to be equal within each of the cooling 1051, 1052, 1053, 1054, 1055, 1056, 1057, 1058, 1059, 1060, and 1061. The model was constructed for both summer and winter processing conditions with the summer results presented in Table 3 and the winter results present in Table 4.
TABLE-US-00003 TABLE 3 Results Assuming Summer Processing Conditions. Pond Ambient % Change decrease Depth Ambient Air Relative Average temperature (feet) Temperature Humidity Windspeed (from average of inlets 1064 (° F) (%) (km/h) and 1066 to outlet 1012) 9 61.5 65 20 21.6% 6.5 61.5 65 20 29.8% 5 61.5 65 20 31.7%
TABLE-US-00004 TABLE 4 Results Assuming Winter Processing Conditions. Ambient % Change decrease Pond Ambient Air Relative Average temperature Depth Temperature Humidity Windspeed (from average of inlets 1064 (feet) (° F) (%) (km/h) and 1066 to outlet 1012) 9 8.8 75 20 52.3% 6.5 8.8 75 20 57.2% 5 8.8 75 20 61.0%
[0051] The results of the summer and winter modeling summarized in Tables 3 and 4 demonstrate that cooling pond systems 1050 designed to have individual cooling ponds 1000 with shallower pond depths 1034 demonstrate increased cooling performance. Shallower cooling ponds 1000 have higher velocities as compared to a comparable cooling pond having increased depths. The higher velocities result in a higher Reynolds number within cooling pond 1000, thereby enhancing flow mixing throughout the vertical stratified brine column of brine solution 1046. With increased flow mixing, the brine temperature at pond surface 1030 is increased resulting in larger conductive and evaporative heat losses at the pond surface 130. Increasing heat loss at the pond surface 1030 through the cooling pond system 1050 directly impacts the brine outlet stream 1012 and ultimately leads to reduced brine outlet stream temperatures.
Example 2
[0052] In Example 2, a temperature profile was modeled relating to the cooling associated with first inlet stream 1064 through part of the cooling pond system 1050 before combining with the outlet stream 160a. With reference to
TABLE-US-00005 TABLE 5 First Inlet Stream 1064 Cooling Assuming Summer Processing Conditions. Total Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp between between between between between between between Ambient Ambient 1064 1051a 1052a 1053a 1054a 1055a 1064 Pond Air Relative Average and and and and and and and Depth Temperature Humidity Windspeed 1051a 1052a 1053a 1054a 1055a 1056a 1056a (feet) (° F.) (%) (km/h) (° F.) (° F.) (° F.) (° F.) (° F.) (° F.) (° F.) 9 61.5 65 20 −7.7 −5.1 −3.8 −3.2 −2.3 −2.0 −24.1 6.5 61.5 65 20 −8.7 −5.4 −4.0 −3.4 −2.3 −2.0 −25.8 5 61.5 65 20 −9.4 −5.9 −4.1 −3.4 −2.4 −1.9 −27.1
TABLE-US-00006 TABLE 6 First Inlet Stream 164 Results Assuming Winter Processing Conditions. Total Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp between between between between between between between Ambient Ambient 1064 1051a 1052a 1053a 1054a 1055a 1064 Pond Air Relative Average and and and and and and and Depth Temperature Humidity Windspeed 1051a 1052a 1053a 1054a 1055a 1056a 1056a (feet) (° F.) (%) (km/h) (° F.) (° F.) (° F.) (° F.) (° F.) (° F.) (° F.) 9 8.8 75 20 −13.6 −9.7 −7.7 −7.8 −5.7 −5.4 −49.9 6.5 8.8 75 20 −15.2 −10.6 −8.5 −8.2 −6.4 −6.1 −55.0 5 8.8 75 20 −16.7 −11.3 −9.0 −8.5 −6.8 −6.4 −58.7
Example 3
[0053] In Example 3, a temperature profile was modeled relating to the cooling associated with second input stream 1066 through the part of the cooling pond system 1050 before combining with the outlet stream 1056a. With reference to
TABLE-US-00007 TABLE 7 Second Input Stream 1066 Results Assuming Summer Processing Conditions. Total Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp between between between between between Ambient Ambient 1066 1057a 1058a 1059a 1064 Pond Air Relative Average and and and and and Depth Temperature Humidity Windspeed 1057a 1058a 1059a 1060a 1056a (feet) (° F.) (%) (km/h) (° F.) (° F.) (° F.) (° F.) (° F.) 9 61.5 65 20 −4.5 −3.4 −3.0 −2.4 −13.3 6.5 61.5 65 20 −4.9 −3.8 −3.3 −2.5 −14.5 5 61.5 65 20 −5.5 −4.0 −3.5 −2.5 −15.5
TABLE-US-00008 TABLE 8 Second Input Stream 166 Results Assuming Winter Processing Conditions. Total Δ Temp Δ Temp Δ Temp Δ Temp Δ Temp between between between between between Ambient Ambient 1066 1057a 1058a 1059a 1064 Pond Air Relative Average and and and and and Depth Temperature Humidity Windspeed 1057a 1058a 1059a 1060a 1056a (feet) (° F.) (%) (km/h) (° F.) (° F.) (° F.) (° F.) (° F.) 9 8.8 75 20 −9.1 −7.4 −6.7 −5.6 −28.8 6.5 8.8 75 20 −9.2 −9.1 −7.4 −6.4 −32.1 5 8.8 75 20 −9.2 −10.7 −7.9 −7.0 −34.8
[0054] In comparing the impact of pond depth 1034 to cooling performance for the above three examples, a comparison of the summer vs. winter results indicates that cooling performance relative to brine outlet stream 1012 is less sensitive to changes in pond depth 1034 during the summer months. It appears that the significantly higher ambient air temperature of the summer months results in a lower heat transfer driving force that negatively impacts cooling performance.
[0055] Based on the total cooling performance of the system 1050 as contained in Tables 3 and 4, production of potassium containing salts was modeled for both summer and winter periods assuming depths of 5 feet, 6.5 feet, and 9 feet. Estimated production levels are listed within Table 9.
TABLE-US-00009 TABLE 9 Potassium-Containing Salt Production % Gain Winter Production % Summer Production Pond Depth Gain % Gain 1034 (compared to 9 ft. (compared to 9 ft. (feet) depth production) depth production) 9 — — 6.5 11.9% 6.4% 5 21.0% 11.4%
[0056] Based on the production data of Table 9, one method for controlling or meeting production goals throughout the year is to adjust pond depth 1034 as opposed to increasing the input flow rates of the inlet streams 1010 including, for example, first inlet stream 1064 and second inlet stream 1066.
[0057] As described throughout supra, a cooling pond system of the present invention utilizes one or more submerged dams and/or variations in cooling pond depths to increase cooling performance and product recovery from a brine, including, but not limited, a cavern raw feed brine in solution mining operations, crystallizer overflow and/or refinery overflow streams in solution or traditional mining operations, a body of salt water, or any other source of brine. It is to be understood that the design of the cooling pond system is amenable to various modifications and alternative forms based upon available area, capital outlay and brine stream parameters. The intention is not to limit the present invention to the particular embodiments described and illustrated but instead to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.