Dual separation principle based arrangement for an acid stream

Abstract

The invention relates to separation arrangements for inputting a input stream with an (strong) aid compound and outputting a (first) useable output stream and simultaneously a (second) disposable output stream, methods for generating said output streams from said input stream and control methods and systems pertaining thereto.

Description

[0001] DUAL SEPARATION PRINCIPLE BASED ARRANGEMENT FOR AN ACID STREAM

[0002] FIELD OF THE INVENTION

[0003] The invention relates to separation arrangements for inputting a input stream with an (strong) aid compound and outputting a (first) useable output stream and simultaneously a (second) disposable output stream, methods for generating said output streams from said input stream and control methods and systems pertaining thereto.

[0004] BACKGROUND OF THE INVENTION

[0005] Arrangements for the above outlined purpose exist but are highly energy in-efficient.

[0006] AIM OF THE INVENTION

[0007] The invention provides a template for such separation arrangements which energy efficient.

[0008] SUMMARY OF THE INVENTION

[0009] The invention relates to an arrangement (10) (as shown in Figure 2), inputting a (waste) input stream (100) with an (strong) aid compound with concentration A which is too high to be disposable but also too low to be useful in or valuable for other processes and outputting a (first) useable output stream (110) with an output concentration B (of said (strong) acid compound), not only higher than A but also higher than a given under bound U and simultaneously a (second) disposable output stream (120) with an output concentration C, not only lower than A but also lower than a given upper bound D, said (first) useable outstream and said (second) disposable output stream are generated from said input stream, the arrangement comprises a first system (20) and second system (30), said first system inputs said input stream (100) and outputs a first intermediate output stream (130), which is inputted to a second system (30), the intermediate concentration F (of said (strong) acid compound), of said first intermediate output stream (130) is smaller than A but still above D, said first system further outputs an output stream (140) with concentration E (of said (strong) acid compound), which will eventually become part of or be entirely the output stream (110), wherein the arrangement is characterized in that the separation principle used in (at least part of) the first system and the second system is based on an essentially different mechanism. In an embodiment of this arrangement the second system outputs two output streams, one of those output stream (150) has a concentration H (of said (strong) acid compound), which is higher than F while the other output stream (160) has a concentration G (of said (strong) acid compound), lower than F.

[0010] In a further embodiment thereof (as shown in Figure 3), the output stream (160) with concentration G (of said (strong) acid compound), lower than the disposable limit, equals output stream C (120).

[0011] In an embodiment of the invention the arrangement (as shown in Figure 4), has a System 1 comprises two subsystems (of which at least one has a separation principle being essentially different than the one used in the second system) which may have a separation principle which is essentially based on the same mechanism but with just different operating points.

[0012] In an alternative embodiment of the invention the arrangement has a System 1 comprises two subsystems (of which at least one has a separation principle being essentially different than the one used in the second system) which have a separation principle which is also essentially different.

[0013] In another embodiment the input stream (100) enters subsystem 1 (40), generating an output stream (170) with concentration I (of said (strong) acid compound), already below the disposable limit and an intermediate output stream (180), inputted into the second subsystem (50), which generates the intermediate output stream (130) with concentration J (of said (strong) acid compound and an output stream (140), which will eventually become part of or be entirely the output stream (110).

[0014] In a further embodiment (as shown in Figure 5), wherein the output stream (160) with concentration G (of said (strong) acid compound), lower than the disposable limit is mixed with the output stream (170), the mixture then becomes output stream C (120).

[0015] In another embodiment in the arrangement (as shown in Figure 3, 5) the output stream (150) and the output stream (140) are mixed and hence jointly become the outstream (110). In an alternative arrangement (as shown in Figure 6), the output stream (150) is fed it back as input to first system (more particular said first subsystem).

[0016] In an alternative arrangement (as shown in Figure 7 or 8), wherein System 2 comprises two (or more) subsystems, which have a separation principle which is essentially based on the same mechanism (but with just different operating points).

[0017] In a further embodiment part of the output streams of subsystems is fed it back as input to second system (more particular first subsystem thereof).

[0018] In an embodiment of the invention in the arrangement (at least part of) system 1 and / or one or more of its subsystems are based on evaporation while system 2 and / or its subsystems are based on electrochemistry and / or electrolysis. In a particular embodiment all system 1 and all of its subparts are based on evaporation. In an alternative embodiment, system 1 is using both separation principles and hence its subparts are of a different nature. In a particular embodiment thereof system 1 is a concatenation of a electrochemistry and / or electrolysis based subsystem (one or more of those) and a subsystem based on evaporation (one or more of those), followed by System 2 as outlined above. Fed back loops within such System 1 are also possible.

[0019] DETAILED GENERIC DESCRIPTION OF THE INVENTION

[0020] As shown in Figure 1, the invention relates to an arrangement (10), inputting a (waste) input stream (100) (with a certain flow rate) with an compound (strong) acid) concentration A which is too high to be disposable (according to given regulations) but also too low to be useful in or valuable for other processes.

[0021] The aim of the invention is to generate from that input stream a (first) useable output stream (110), hence with an output concentration B, not only higher than A but also higher than a given under bound U and simultaneously a (second) disposable output stream (120), hence with an output concentration C, not only lower than A but also lower than a given upper bound D. This is illustrated at the right side of Figure 1. As shown in Figure 2, the arrangement comprises a first system (20), inputting said input stream (100) and outputting a first intermediate output stream (130), which is inputted to a second system (30). Said first system further outputs an output stream (140) with concentration E, which will eventually become part of or be entirely the output stream (110). Note that due to this last requirement E is larger dan U. While the intermediate concentration F is smaller than A, it is still above D, hence requires further processing in the second system.

[0022] The arrangement is characterized in that the separation principle used in the first system and the second system is based on an essentially different mechanism.

[0023] The arrangement is further characterized in that the design (in terms of further subsystems, operating set-ups such as flow rates, pressures, temperature) is selected in that the intermediate concentration F is suitable for the second system both in terms of durability (corrosion aspects) and in terms of its separation capabilities, which requires the second systems input concentration F to be within a given boundary.

[0024] The second system outputs two output streams, one of those output stream (150) has a concentration H which is higher than F while the other output stream (160) has a concentration G lower than F.

[0025] In an embodiment of the invention as shown in Figure 3, the output stream (150) and the output stream (140) is mixed and hence jointly become the outstream (110) satisfying the requirement to be useful. It is worth mentioning that system 2 has limited capability to raise its input stream concentration F to a higher concentration and hence concentration H is lower than U. Note that diluting an already useful stream without making it not useful is allowed. In the embodiment of this Figure 3, the design is selected in that the output stream (160) with concentration G lower than the disposable limit. The output stream (160) hence equals output stream C (120).

[0026] It is worth mentioning at this stage that the flow rate of stream (160) is substantially higher than the flow rate of stream (150) and that the flow rate of stream (150) is substantially lower than the flow rate of stream (140).

[0027] In an embodiment of the invention as shown in Figure 4, System 1 comprises two subsystems, which have a separation principle which is essentially based on the same mechanism but with just different operating points. Similar as the overall system they define, they need to generate streams with a higher concentration. The input stream (100) enters subsystem 1 (40), generating an output stream (170) with concentration I, already below the disposable limit and an intermediate output stream (180), inputted into the second subsystem (50), which generates the intermediate output stream (130) with concentration J and an output stream (140), which will eventually become part of or be entirely the output stream (110). It is worth noting here that the choice of using two subsystem is to obtain an intermediate concentration F within the operating boundary of system 2. Note that in certain scenarios, input concentration A is so low that system 1 should generate an final output stream having a lOx concentration while System 2 by its nature cannot reach such effect. However it is also remarkable that to achieve such performance by system 1 (or its subsystems) that an auxiliary or intermediate stream which is too high in concentration F (in terms of disposability) also get generated but which is fortunately within the operating boundaries of systems like system 2.

[0028] As shown in Figure 4, 5 and 6 in an exemplary embodiment of the Figure 4 embodiment one may similar as in the embodiment of Figure 3, mix the output stream (150) and the output stream (140).

[0029] As shown in Figure 5 in an exemplary embodiment of the Figure 4 embodiment one may select the design in that the output stream (160) with concentration G lower than the disposable limit and then mix it with the output stream (170), the mixture then becomes output stream C (120). Note that while diluting a not disposable flow to make it disposable is generally not allowed, mixing already disposable stream is allowed.

[0030] As shown in Figure 6, in an alternative exemplary embodiment of Figure 4, one may select the design in that the output stream (150) with concentration H is fed it back as input to first system (more particular first subsystem).

[0031] As shown in Figure 7, in an alternative exemplary embodiment of Figure 4, also System 2 comprises two subsystems , which have a separation principle which is essentially based on the same mechanism but with just different operating points. The respective high concentration output streams may be combined with stream (140) to obtain the final output while one may select the design in that the output stream of subsystem 22 is fed it back as input to second system (more particular first subsystem thereof) and hence get combined with the stream (130). The resulting concentration L must remain with the operating range of subsystem 21. As shown in Figure 8, in an alternative exemplary embodiment of Figure 4, System 2 comprises three subsystems , which have a separation principle which is essentially based on the same mechanism but with just different operating points. The resulting output stream of those subsystems can be combined to define the final output flows (both high or low) and / or can be fed-back.

[0032] More generally speaking the operating conditions (flow rates relative to one another, operating voltage of the electrochemical cells) are optimized based on the following technical considerations and implemented by use of an intelligent controller, in particular by the requirement to maximize the concentration of B with as constraint the concentration of C being the discharge limit while simultaneously minimize the energy demand and maximize the volume of C.

[0033] Further variants are described in Figures 9 to 11.

[0034] EXAMPLARY EMBODIMENTS OF THE INVENTION

[0035] In an exemplary embodiment of the invention the concentration A is in the range of a sulpuric acid concentration of 1-70% , preferably between 20% and 55% and even more preferably between 40% and 50%.

[0036] If the concentration of A is below 20%, subsystem 1.1 is a pre-processing system based on electrodialysis for concentrations below 20% to reach a concentration of 20% Subsystem 1.1 will produce a stream ‘I’ with a sulphate concentration below 90 mg / 1 that already meets the discharge limit for sulphate in surface water. The operating range of system 2 is a sulphuric acid concentration of 0,2 -15%, preferably between 1 and 10%.

[0037] When flow J has a sulphuric acid concentration of 50%, flow F has a sulphuric acid concentration of 0,5-2% with a flow rate 25-35% of flow J when flow E has a concentration of 81% and flow rate of 65-75% of flow J.

[0038] The flow rate of H is between 5 and 15 times less than flow rate of F and between 15 and 25 times less than flow rate of E. The flow rate of G is 85-95% of F or 5-20 times less than flow rate of H, see Figure 6. The concentration of H is between 5 and 15 times bigger than the concentration of F and between 5 and 15 times less than the concentration of E. The concentration of G is 5-50% of F depending on the amount of subsystems you have in system 2.

[0039] System 2 is then an electro chemical cell operates at a voltage of 0 to 40 Volt, more optimal between 10 and 20 V.

[0040] It is the aim of the inventio is to produce a big volume of dischargeable water with a limited electrical input. Compared to distillation of stream F to reach the concentration of J, system 2 uses 80-90% less energy, including the energy demand for distillation of stream H.

[0041] Concentration of I is below D, being the discharge limit of a local government. In Europe this limit can vary depending on the receiving water body.

[0042] In a further detailed example of the foregoing and seen in Figure 8, the flow of F is 44 m3 / day and the sulphuric acid concentration is 1,25% entering subsystem 2.1. The output stream H21 has a sulphuric acid concentration of 6,74 m% with a flow rate of 3.4 m3 / day and the output stream G21 has a flow rate of 40,6 m3 / day with a concentration of 0,793 m% sulphuric acid. The energy consumption of system 2.1 is 190,3 kWh per day. Passing a second subsystem 2.2. the flow of G21 is 40,6 m3 / day and the sulphuric acid concentration is 0,793 m% entering subsystem 2.2. The output stream H22 has a sulphuric acid concentration of 7.36 m% and a flow rate of 3,1 m3 / day and the output stream G22 has a flow rate of 37,5 m3 / day with a concentration of 0,245 m% sulphuric acid and is mixed in stream I to produce a stream C with a sulphuric acid concentration below the discharge limits. The energy consumption of system 2.2 is 195,6 kWh per day. The total electrical energy consumption of system 2 is 385,9 kWh per day.

[0043] Compared to a distillation process with mechanical vapor recompression where flow F enters at 44 m3 / day with a sulphuric acid concentration of 1 ,25% and the output concentrate has a sulphuric acid concentration of 6,58 m% with a flow rate of 8,35 tons / day and the output condensate has a flow rate of 35,65 tons / day with a concentration of 0,08 ppm sulphuric acid, the electrical energy demand of the distillation process would be 4499 kWh per day, being 11,6 times higher than system 2 and there is an extra thermal energy demand of 6478 kWh per day. While the water quality of the distillation process is better than system 2 but it has no added value as the discharge limits for sulphate are more in the range of 90-2500 ppm depending on the receiving water body. Increasing the concentration in the condensate of the distillation process will not decrease the energy demand, showing an important improvement of system 2 in energy demand compared to the state of the art distillation.

[0044] Further, the operating conditions of system 2 are at a temperature < 35 °C and atmospheric pressure, this opens a new range of corrosion resistant materials that are not possible in a distillation tower as the operating conditions are either >100°C and >l bar.

[0045] In an alternative embodiment of the invention, the (relative) flow rate of H is between a few times less than flow rate of A and selected to ensure the concentration K (as shown in Figure 6) lies within the operating range of subsystem 11. This approach still maximizes the concentration B because the later addition of H will result in a still acceptable lowering.

Claims

CLAIMS1. An arrangement (10) inputting a input stream (100) with an (strong) aid compound with concentration A and outputting a (first) useable output stream (110) with an output concentration B, not only higher than A but also higher than a given under bound U and simultaneously a (second) disposable output stream (120) with an output concentration C, not only lower than A but also lower than a given upper bound D, the arrangement comprises a first system (20) and a second system (30), said first system inputs said input stream (100) and outputs a first intermediate output stream (130), which is inputted to said second system (30), the intermediate concentration F of said first intermediate output stream (130) is smaller than Abut still above D, said first system further outputs an output stream (140) with concentration E, wherein the arrangement is characterized in that the separation principle used in (at least part of) the first system and the second system is based on an essentially different mechanism.

2. The arrangement of claim 1, wherein the second system outputs two output streams, one of those output stream (150) has a concentration H which is higher than F while the other output stream (160) has a concentration G, lower than F.

3. The arrangement of claim 2, wherein the output stream (160) with concentration G, lower than the disposable limit, equals output stream C (120).

4. The arrangement of claim 1 or 2 wherein System 1 comprises two (or more) subsystems (of which at least one has a separation principle being essentially different than the one used in the second system), which may have a separation principle which is essentially based on the same mechanism but with just different operating points.

5. The arrangement of claim 4, wherein the input stream (100) enters subsystem 1 (40), generating an output stream (170) with concentration I below the disposable limit and an intermediate output stream (180), inputted into the second subsystem (50), which generates the intermediate output stream (130) with concentration J and an output stream (140).

6. The arrangement of claim 4 or 5 wherein the output stream (160) with concentration G, lower than the disposable limit is mixed with the output stream (170), the mixture then becomes output stream C (120).

7. The arrangement of any of the previous claims wherein the output stream (150) and the output stream (140) are mixed and hence jointly become the outstream (110).

8. The arrangement of any of the claims 1 to 6 (as shown in Figure 6), wherein the output stream (150) is fed it back as input to the first system.

9. The arrangement of any of the previous claims, wherein System 2 comprises two (or more) subsystems (typical electrochemical cells), which have a separation principle which is essentially based on the same mechanism but with just different operating points.

10. The arrangement of claim 9 (as shown in Figure 7), wherein part of the output streams of subsystems is fed it back as input to second system.

11. The arrangement of any of the previous claims wherein system 1 and / or one or more of its subsystems are based on evaporation and optionally one or more subsystem based on electrochemistry and / or electrolysis and / or electrodialysis12. The arrangement of any of the previous claims wherein system 2 and / or its subsystems are based on electrochemistry and / or electrolysis and / or electrodialysis .

13. The arrangement of any of the previous claims, further comprising with one or more pumps and / or valves on one or more of said streams and a control system operating those one or more pumps and / or valves and / or setting the operating voltages for the electrochemistry and / or electrolysis in order to operating the systems and / or subsystems within their selected operating condition and / or retaining the concentrations within the operating condition range of those systems.

14. The arrangement of any of the previous claims, further comprising one or more elements for heat recuperation and / or pre-heating one or more of said streams.

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