TECHNICAL FIELD

[001] The present subject matter generally relates to an evaporator and a method of making the evaporator. More specifically the present subject matter relates to a Mechanical Vapour Compressor (MVC) based evaporator and a method of making the same.

BACKGROUND

[002] Disposal of waste/effluent/liquid is strongly regulated and often prohibited in surface-water, sewer and deep well. Therefore, industrial waste/effluent/liquid is required to be treated before it is disposed. A most desirable treatment of such waste/effluent/liquid is when the treatment results in minimal to Zero Liquid Discharge (ZLD ^® ). MVC based evaporators are one of the most attractive choices of waste/effluent/liquid treatment because, they can be employed for treating variety of waste/effluent/liquid, for examples, fruit juices; sea water; waste water; milk; acid/alkali etc. and produce relatively less or ZLD ^® .

[003] MVC based evaporators employ boilers to obtain concentrate or crystallization of liquids. Boilers are extremely bulky, expensive and maintenance intensive. Further controlling boilers for optimal and effective operation of the evaporator is complicated and skill driven. Therefore, it is desirable that an evaporator is provided that substantially addresses these and other limitations associated with the boilers of the evaporators.

SUMMARY

[00 ] It is therefore, one of the objects of the subject matter to provide an evaporator and a method of making the evaporator that does not have the above and other limitations. Specifically, the object is to provide an MVC based evaporator (hereinafter "evaporator") and a method of making the same. [005] While an MVC based evaporator is desirable for its versatility, the boilers employed with the evaporator make it expensive and out of reach. The present subject matter provides a solution, wherein the evaporator totally gets rid of the boiler. Therefore making the evaporator more attractive solution. The subject matter provides the evaporator with a humidifier and removes the requirement of the boiler altogether. The subject matter achieves the evaporator, despite of the fact that the steam generated by the boiler, which is on high temperature, and pressure, is no way comparable to the vapours generated by the humidifier, which are on substantially atmospheric conditions.

[006] According to one aspect, the subject matter provides an evaporator (200) comprising: a heat exchanger (237) configured to receive a liquid; a compressor (277) configured to supply compressed-vapours to the heat exchanger (237), and the heat exchanger (237) is configured to thermally couple the liquid and the compressed-vapours to cause heat exchange between the liquid and the compressed-vapours, thereby converting the compressed-vapours into a condensate; and characterized in that a humidifier (293) configured to provide humidifier-vapours to the compressor (277) and the compressor (277) is configured to receive and compress the humidifier-vapours to obtain the compressed- vapours. In a first embodiments, the evaporator comprises a flash vessel (267) configured to receive humidifier-vapours from the humidifier (293) and receive the liquid from the heat exchanger (237) and the flash vessel (267) generates liquid- vapours from the liquid by causing phase separation, and wherein, the compressor (277) is coupled to the flash vessel and the compressor (277) configured to receive and compress the humidifier-vapours and liquid-vapours to obtain the compressed-vapours. In a second embodiment, the evaporator (200) comprises a pressure breaker (297) configured to extract the condensate from the heat exchanger (237) while maintaining the physical parameters of the liquid in the heat exchanger (237) substantially unaltered. In a third embodiment, the evaporator (200) comprises a pressure breaker configured to maintain a pressure differential between humidifier (293) and the heat exchanger (237). In a fourth embodiment, the evaporator (200) comprises a salt settler (2 9) configured to receive the liquid from the heat exchanger (237) and extract salt crystals from the liquid. In a fifth embodiment, the evaporator (200) includes one or more pumps (203, 213, 223 and 2 3) to enable circulation of the liquid of the evaporator (200). In a sixth embodiment the evaporator (200) comprises a feed tank (217) configured to receive the liquid and supply the liquid to the heat exchanger (237). In a seventh embodiment, the evaporator (200) comprises a pre-heater (287) configured to pre- heat the liquid using the condensate.

[007] According to a second aspect, the subject matter provides, a method of manufacturing an evaporator (200) comprising: configuring a heat exchanger (237) to receive a liquid; configuring a compressor (277) to supply compressed-vapours to the heat exchanger (237), and configuring the heat exchanger (237) to thermally couple the liquid and the compressed-vapours to cause heat exchange between the liquid and the compressed-vapours, thereby converting the compressed-vapours into a condensate; characterized in that configuring a humidifier (293) to provide humidifier-vapours to the compressor (277) and configuring the compressor (277) to receive and compress the humidifier-vapours to obtain the compressed-vapours. In a first embodiment, the method comprises providing a flash vessel (267) and configuring the flash vessel (267) to receive humidifier-vapours from the humidifier (293) and receive the liquid from the heat exchanger (237) and configuring the flash vessel (267) to generate liquid-vapours from the liquid by causing phase separation, wherein configuring the compressor (277) comprises coupling the flash vessel (267) and the compressor (277) and configuring the compressor (277) to receive and compress the humidifier-vapours and liquid-vapours to obtain the compressed-vapours. In a second embodiment, the method comprises providing a pressure breaker (297) to enable extraction of the condensate from the heat exchanger (237) while maintaining the physical parameters of the liquid in the heat exchanger (237) substantially unaltered. In a third embodiment, the method comprises providing a pressure breaker (297) to maintain a pressure differential between the humidifier (293) and the heat exchanger (237). In a fourth embodiment, the method comprises providing configuring a salt settler (2 9) to receive the liquid from the heat exchanger (237) and extracting salt crystals from the liquid. In a fifth embodiment, the method comprises configuring a feed tank (217) to receive the liquid and supply the liquid to the heat exchanger (237) and providing one or more pumps (203, 213, 223 and 2 3) to enable circulation of the liquid across the evaporator (200). In sixth embodiment, the method comprises configuring a pre- heater (287) to pre-heat the liquid using the condensate.

BRIEF DESCRIPTION OF DRAWINGS

[008] The subject matter is now described with reference to the accompanying figures, in that:

[009] FIG. 1 shows a schematic diagram of an evaporator according to an embodiment of a prior art;

[0010] FIG.2a shows a concept diagram of an evaporator according to an embodiment of the present subject matter;

[0011] FIG.2b shows a more detailed concept diagram of an evaporator according to an embodiment of the present subject matter; [0012] FIG.2C shows an evaporator according to an embodiment of the present subject matter;

[0013] FIG.2d shows an evaporator according to another embodiment of the present subject matter; and

[001 ] FIG. 3 shows a block diagram of an embodiment of a method of manufacturing an evaporator of the present subject matter. DETAILED DESCRIPTION

[0015] The following discussion is intended only for illustration purpose and not to limit the subject matter to the described embodiments. For explanation, some features may have been emphasized while others are not. It is also to be understood that the terminology used is not intended to be limiting and singular forms "a", "an", and "the" include plural references unless the context clearly expressly dictates otherwise.

[0016] FIG. 1 shows a schematic diagram of an evaporator 100 according to an embodiment of a prior art. FIG. 1 includes feed lines 101, 107 and 111, a feed-in pressure gauge 109, pumps 103, 113 and 123, valves 105, 115, 125, 135, 1 5, 155, 165, 175 and 185, connecting lines 121, 1 1, 161, 163, 171 and 173, a feed tank 117, an FT-input 119, an FT-output 189, an output line 181, an input 127 to the pump 113, a heat exchanger 137, HE-inputs 129, and 13 , an HE-output 131, an HE-vent 139, a salt settler 1 9, a boiler 157, a flash vessel 167, an FV- window 169, a compressor 177, an FT-window 179, and a pre-heater 187.

[0017] The constructional details of the evaporator 100 are as follows. The feed line 101 is coupled to the input of the pump 103. The output of the pump 103 is coupled to the input of the valve 105. The output of the valve 105 is coupled to the feed-in pressure gauge 109 and to a first input of the pre-heater 187. The output of the valve 105 is also coupled to the input of the valve 115 through the feed line 107. The output of the valve 115 is coupled to the feed tank 117 through the feed line 111. A first output of the pre-heater 187 is coupled to the feed tank 117 through the valve 125 and the feed line 111. The feed tank 117 has one input as FT-input 119. The feed tank 117 is provided with the FT-window 179. The feed tank 117 has one output as the FT-output 189. The FT-output 189 is coupled to the input 127 of pump 113 through the valve 135. The output of pump 113 is coupled to the HE-input 129 of the heat exchanger 137. The valve 1 5 is provided at the input of the pump 113. The valve 155 is provided at the output of the pump 113. The H E-input 129 is also coupled to the input of the pump 123. The output of the pump 123 is connected to the input of the salt settler 1 9. The output of the salt settler 1 9 is coupled to the feed tank 117 via the connecting line 141. The boiler 157 is coupled to the HE-input 13 of the heat exchanger 137. The H E- output 131 of the heat exchanger 137 is coupled to the valve 165. The output of the valve 165 is coupled to the output line 181 through the valve 175. A second output of the pre-heater 187 is also coupled to the output line 181 through the valve 185. The heat exchanger is provided with an H E-vent 139. An output of the heat exchanger 137 is coupled to the flash vessel 167 through the connecting line 161. The flash vessel 167 is provided with the FV-window 169. A first output of the flash vessel 167 is coupled to the feed tank 117 via the connecting line 163. A second output of the flash vessel 167 is connected to the input of the compressor 177 through the connecting line 171. The output of the compressor 177 is coupled to an input of the heat exchanger 137 via the connecting line 173. A third output of the flash vessel 167 is connected to the input 127 of the pump 113 through the connecting line 121.

[0018] Function of the evaporator 100 can be understood as follows. Liquid is introduced into the feed tank 117 through the feed lines 101, 107, 111, pump 103 or the FT-input 119. The boiler 157 is provided with water. The feed-in pressure gauge 109 is used to monitor the pressure of the liquid. The valves 105, 115 and 125 are turned on/off to direct the liquid into the feed tank 117 directly or through the pre-heater 187. The liquid is transferred from the feed tank 117 to the heat exchanger 137 and is re-circulated between the heat exchanger 137 and the flash vessel 167 through the pump 113 and the connecting lines 121, 163, 161, the input 127 and the H E-input 129. The valves 135, 1 5, 155 enable smooth circulation of liquid. Steam of the boiler 157 is used to heat the liquid in the heat exchanger 137. The steam is injected into the heat exchanger 137 at the H E-input 13 and brought in thermal contact with the liquid. Thus, the boiler plays an important role of initiating the evaporator 100 by supplying the initial heat required to bring the liquid to boiling point. When heated liquid reaches the flash vessel 167 due to sudden change in physical parameters, the liquid undergoes the phase separation resulting in generation of liquid-vapours. The compressor 177 is used to collect the liquid-vapours from the flash vessel 167 via connecting line 171 and to compress the liquid-vapours to obtain compressed-vapours. The compressed-vapours are introduced into the heat exchanger 137 via connecting line 173 and brought in thermal contact with the liquid to heat the liquid further. The compressed-vapours lose some heat in the recirculation process this heat is required for sustained operation of the evaporator 100. In this case, the boiler 157 instead of being a primary source of energy to heat the liquid plays a role to makeup for the heat lost by the compressed-vapours in circulation. Thus, the boiler 157 plays an important role in sustaining the evaporation action. The vaporization causes the liquid to become concentrated and the compressed-vapours produce condensate. The condensate may be collected through the HE-output 131 at the output line 181, via the valve 165 and any one of the valves 175 or 185. The valves 175 and 185 direct the condensate via the pre-heater 187 thereby pre-heating the liquid at the feed in 101. Pump 123, connecting line 141 are used to direct the liquid to the feed tank 117 through the salt settler 149. The salt settler 1 9 may filter any salt that may have crystallized during the process. The FV-window 169, and the FT-window 179 may enable monitoring inside of the flash vessel 167 and the feed tank 117 respectively. The FT-output 189 may be used to drain the feed tank 117 and the HE-vent 139 is used to vent out non-condensable gases.

[0019] The problems associated with the above evaporator 100 and the principle of solution provided by the present subject matter shall now be discussed with reference to the evaporator 100 of FIG. 1 and the evaporators 200 shown in FIG. 2a through FIG. 2d. As apparent from the foregoing discussion that the boiler 157 plays an important role in functioning of the evaporator 100 and without the boiler 157 is evaporator 100 shall render itself useless. One of the reason for which the boiler 157 becomes indispensable is its ability to controllably generate steam at desired pressure and temperature. While, the boiler 157 is so critically important for the evaporator 100, at the same time, the boiler 157 is also a major reason for high infrastructure, energy and otherwise operational costs.

[0020] According to one aspect, the present subject matter solves the problems encountered due to erecting and commissioning the boiler 157 and other problems associated with boilers 157 of the evaporators 100 by totally getting rid of the boiler 157 altogether. However, getting rid of the boiler 157 from the evaporator 100, without rendering the evaporator 100 useless is easier said than done because of the above discussed critical roles the boiler plays in an evaporator. The subject matter solves this problem by employing a humidifier 293 (shown in FIG. 2a through FIG. 2d) and removes the boiler 157 altogether. The humidifier 293 is less energy intensive and extremely cost effective solution as compared to the boiler 157. However, the humidifier 293 creates problems of its own. The problem with the humidifier 293 is that, it barely produces any steam that may be used for heating the liquid and initiating the evaporation process. This is because, temperature and pressure of the vapours generated by the humidifier 293 (humidifier-vapours) is almost same as the atmospheric temperature and pressure and are no way comparable to extremely high and controllable temperature and pressure of the steam of the boiler 157. This limitation of the humidifier 293 renders humidifier 293 useless for an evaporator 200 (shown in FIG. 2a through FIG. 2d). Therefore, mere replacement of the boiler 157 with the humidifier 293 is no solution. The present subject matter also solves these and other conflicts without substantially compromising on the evaporator 200 functioning and achieving a more economically viable solution.

[0021] The subject matter solves the above and other problems by supplying additional energy to the humidifier-vapours to make the humidifier- vapours good for the evaporator 200. However, supplying additional energy must be achieved at minimum cost and possibly using existing infrastructure for industrially viability, and cost effective when compared with the boiler 157. [0022] The subject matter provides a solution to the above and other problems by employing a low energy consuming and safe humidifier 293, in conjunction with a compressor 277 (shown in FIG. 2a through FIG. 2d). The subject matter achieves this by ensuring that the boiler 157 is not merely replaced by the humidifier 293 but, unlike boiler 157 which is coupled to the heat exchanger 137 of prior solutions, the humidifier 293 is rather coupled to the compressor 277. Coupling the humidifier 293 to the compressor 277 ensures that humidifier- vapours are not directly fed into a heat exchanger 237 (shown in FIG. 2a through FIG. 2d) instead, humidifier-vapours are fed to the compressor 277. In the shown examples of FIG. 2b, FIG. 2c and FIG. 2d the humidifier-vapours are fed to the compressor 277 through a flash vessel 267. The compressor 277 compresses the humidifier-vapours to obtain the compressed-vapours. The process of compression results in supplying additional energy to the humidifier-vapours. The compressed- vapours have the temperature and pressure sufficient enough to cause heat exchange between the liquid and the compressed-vapours to result in increase in the temperature of the liquid. Thereby effectively employing the available infrastructure, while achieve a more effective and efficient evaporator 200. Having explained the principle and reasoning of the evaporator 200 of the present subject matter in the context of the evaporator 100, more constructional and functional details of the embodiments of the evaporators 200 of the subject matter are now discussed below with reference to the FIG. 2a through FIG. 2d.

[0023] FIG. 2a is a basic concept diagram of the evaporator 200 according to an embodiment of the present subject matter. In that, FIG. 2a shows pumps 203, 213, 223, and 2 3, a feed tank 217, the heat exchanger 237, a salt settler 2 9, the flash vessel 267, the compressor 277, the humidifier 293, a connecting line 263, a pre-heater 287 and a pressure breaker 297. A maze of pumps 203, 213, 223, connecting line 263 and the pre-heater 287 couples the heat exchanger 237, the feed tank 217, a pressure breaker 297, the salt settler 2 9, the flash vessel 267. [002 ] FIG. 2b is a more detailed concept diagram in that, it shows all the elements referenced in FIG. 2a and more detailed connections of these elements. It also shows a FT-window 279. The heat exchanger 237 is coupled to the feed tank 217, the flash vessel 267, the pressure breaker 297, the humidifier 293 and the compressor 277. The humidifier 293 is coupled to the flash vessel 267. The flash vessel 267 is also coupled to the feed tank 217 through connecting line 263. The compressor 277 coupled to the flash vessel 267. The salt settler 2 9 coupled to the heat exchanger 237 and feed tank 217. A maze of pumps 203, 213, 223 and 2 3 are coupled to various lines running across the evaporator 200 to ensure uninterrupted circulation of the liquid and vapours across the heat exchanger 237, the pre-heater 287, the flash vessel 267, the feed tank 217 etc.

[0025] FIG. 2C and FIG. 2d both show more detailed embodiments of the evaporator 200. Both FIG. 2c and FIG. 2d show all the elements referred with reference to FIG 2a and FIG. 2b. Both FIG. 2c and FIG. 2d show additional elements in that they show: feed lines 201, 207 and 211, a feed-in pressure gauge 209, valves 205, 215, 225, 235, 2 5, 255, 265, 275, 285, 2 7 and 295, connecting lines 221, 2 1, 261, 271, 273, 281 and 291, HE-tubes 236, a FT-input 219, a FT- output 289, an input 227 of the pump 213, a HE-input 229, a HE-output 231, a pressure gauge 259, a level gauge 253, a HE-vessel 238, a HE-vent 239, a FV- window 269, a liquid inlet 299, and an output line 283.

[0026] The only constructional difference in the embodiments of

FIG. 2C and FIG. 2d is whether the HE-tubes 236/HE-vessel 238 carries the liquid or compressed-vapours. The FIG. 2c shows the liquid from the HE-input 229 is introduced into the HE-tubes 236 and compressed-vapours are introduced in the HE-vessel 238. The FIG. 2d shows the liquid from the HE-input 229 is introduced into the HE-vessel 238 and the compressed-vapours are introduced in the HE- tubes 236. Barring above difference in the construction and corresponding functions, FIG. 2c and FIG. 2d are the same. Therefore, functional aspects of the embodiments of FIG. 2c and FIG. 2d may be understood mutatis mutandis. [0027] The evaporators 200 shown in FIG. 2a through FIG. 2d are now collectively referred and further details are understood as follows.

[0028] The feed tank 217 provides the liquid to the heat exchanger

237 through the valve 235, the input 227, the pump 213 and the HE-input 229. In some examples, the feed tank 217 is configured to receive the liquid through the pre-heater 287 via the feed line 201, the pump 203, the valve 205, 225 and the feed line 211. Employing the pre-heater 287 enables optimal utilization of heat of condensate generated by the evaporator 200 which may be used to pre-heat the liquid. In some examples, the liquid may be fed to the feed tank 217 via the feed line 201, the pump 203, the valves 205, 215 and the feed lines 207, 211. In one option liquid may be received in the feed tank 217 from FT-input 219. The feed tank 217 is provided with the FT-window 279 to view inside the feed tank 217. The feed-in pressure gauge 209 is to monitor pressure in the feed lines 201, 207.

[0029] The heat exchanger 237 configured to receive liquid from the feed tank 217 via valve 235, input 227, pump 213 and the HE-input 229. The liquid is circulated between the heat exchanger 237, flash vessel 267, and feed tank 217 using connecting lines 261 and 221 and pump 213. As stated earlier, in some examples, the HE-tubes 236 and HE-Vessel 238 may carry the compressed-vapours and liquid respectively (FIG. 2d). In some examples, the HE-Vessel 238 and HE- tubes 236 may carry the compressed-vapours and liquid respectively (FIG. 2c).

[0030] To initiate heating of the liquid, a small amount of the liquid or water is fed to the humidifier 293 and heated to obtain humidifier-vapours. Providing water to the humidifier 293 may protect the humidifier from adverse effect of vaporizing liquid, e.g. scaling etc. In one option, the humidifier 293 may employ a heating apparatus for generating humidifier-vapours from the liquid/water. The heating apparatus may be an electrical heating apparatus or any other heating apparatus. The level of the liquid inside the humidifier 293 is monitored using the liquid gauge 253. [0031] In one example, the humidifier-vapours are supplied to the flash vessel 267 via connecting line 281. The compressor 277 is configured to receive vapours present in the flash vessel 267 and compresses it, thereby increasing entropy of vapours and resulting in compressed-vapours. The compression of the vapours creates differential temperature and pressure between the vapours and compressed-vapours. Initially the humidifier-vapours are sucked by the compressor 277 via connecting line 271 because no liquid-vapours have yet been generated in the flash vessel 267. The compressed-vapours are supplied to the heat exchanger 237 via connecting line 273. The heat exchanger 237 is configured to thermally couple the liquid and the compressed-vapours. The thermal contact between the liquid and the compressed-vapours causes heat exchange between the liquid and the compressed-vapours. The heat exchange results in heating of liquid and the compressed-vapours get condensed, resulting in condensate. The process continues till the liquid of the heat exchanger 237 reaches its boiling point. During this process the liquid is circulated between the flash vessel 267 and heat exchanger 237 via the connecting lines 261, 221, the input 227 of the pump 213 and the H E-input 229.

[0032] Once the liquid reaches around boiling point, the liquid undergoes phase separation at the flash vessel 267 and generates liquid-vapours. Effectively, the flash vessel 267 acts a phase changer for the liquid. The liquid- vapours and the humidifier-vapours are sucked into the compressor 277 to generate compressed-vapours which are directed to the heat exchanger 237. As more and more liquid-vapours are generated in the flash vessel 267, role of the humidifier 293 may now start to get limited. Once the liquid-vapours are sufficient in amount, no additional humidifier-vapours are required. This is called a steady state of the evaporator 200. The role of the humidifier 293 may now be limited to maintain the steady state conditions. In some cases, the humidifier 293 may be turned off. I n this manner, the humidifier 293 together with other elements effectively replaces the boiler of the prior art. [0033] The pressure breaker 297 is configured to extract the condensate from the heat exchanger 237. The pressure breaker 297 ensures that the condensate from the heat exchanger 237 is extracted while maintaining pressure differential between the humidifier 293 and the heat exchanger 237. Employing the pressure breaker 297 to keep the pressure differential substantially unaltered, enables substantially continuous operation of the evaporator 200. Thereby making the evaporator 200 attractive, in terms of longer operation cycles, operation cost and others. The evaporator 200 may employ more than one pressure breakers to achieve thermodynamic isolation of its elements. The condensate extracted from the heat exchanger 237 may be provided to the humidifier 293 via the HE-output 231, the valve 295, the pressure gauge 259, the pressure breaker 297, the pump 2 3 and the valve 2 7. The humidifier 293 may use the condensate to generate humidifier-vapours, making the evaporator 200 more water neutral/efficient. Any excess condensate may be routed to pre-heater 287 via the HE-output 231, the valve 295, the pressure breaker 297, the pump 2 3, pressure gauge 259, connecting line 291 and valve 265. At the pre-heater 287 the liquid received from the feed line 201 may be pre-heated using condensate and from the pre-heater 287 the condensate is received at the output line 281 via valve 285. I n some cases, the condensate may by-pass the pre-heater 287 via the valve 275. The gases that do not condense may be extracted from the HE vent 239.

[003 ] Due to evaporation, the liquid becomes concentrated, in some cases, some salts might also get crystallized or liquid may have some particulates, which are required to be removed from the liquid. For extraction of such crystallized salts/particulates, the liquid may be routed from the heat exchanger 237 via the pump 223 and to the feed tank 217 through the salt settler 2 9 via connecting line 2 1. I n some options both the pump 223 and the pump 213 are operational. I n some other options only one of pumps 213 and 223 is operational to enable the routing. I n some cases, additional pressure breakers may be employed for enabling salt settler 2 7. [0035] At the salt settler 249 any crystallized salts and other particulates from the liquid may be extracted/filtered before the liquid is passed to the feed tank 217. Effectively, the salt settler 2 9 acts as a filter. In one possibility, the evaporator 200 is commissioned for crystallization of salts dissolved in the liquid. I n some option the evaporator 200 is commissioned for obtaining compressed-vapours of the liquid. In some examples, the feed tank 217 acts as salt settler and salts/pa rticulates are obtained at the FT-output 289.

[0036] The embodiments show, the humidifier 293 coupled to the compressor 277 through the flash vessel 267 via connecting lines 281 and 271. However, other embodiments in which the humidifier 293 is directly coupled to the compressor 277 are also possible. Coupling the humidifier 293 through the flash vessel 267 offers some advantages. For example, the humidifier 293 is not exposed directly to the compressor 277 and the humidifier-vapours are received in a relatively more stable environment as compared to a rather volatile environment when the humidifier 293 is directly coupled to the compressor 277.

[0037] Some other advantages of the humidifier 293 are: unlike boiler, a separate large source of water is no more required and a small quantity of water may be sufficient for initiating the evaporator 200. Further, the humidifier 293 may be supplied with the liquid that is similar or have the same physical characteristics as that needs to be treated by the evaporator 200. Because the same/similar liquid is being used by the humidifier 293 and the heat exchanger 237, no conflict needs to be negotiated that arise due different boiling point of the liquid and the water of the boiler. Cleaning and commissioning the humidifier 293 is cost effective and very less complicated than the boiler. Further the humidifier 293 is low energy consuming device as compared to the boiler. Needless to say, that all the other disadvantages associated with the boiler, i.e. complications relating to compliance with safety and pollution regulations, commissioning, steady supply of fuel, capital cost, maintenance cost, providing adequate space for installation, and economy of scale also disappear. [0038] Some other accessories that may be provided with the evaporator 200 are valves 2 5, 255 and the FT-output 289. In general, these valves may be used by draining the evaporator 200. For example, the feed tank 217 has one output as FT-output 289 this may also be used to drain the feed tank 217. Similarly, the valve 2 5 and valve 255 may be used for draining the heat exchanger 237 and/or the flash vessel 267. The humidifier 293 may be provided with the level gauge 253 and the liquid inlet 299. The level gauge 253 may be used for monitoring and controlling the level of water/liquid in the humidifier 293 and the liquid inlet 299 may be used for introducing water/liquid into the humidifier 293. The FV- window 269 may be used for monitoring inside the flash vessel 267.

[0039] The present subject matter further provides a method 300

(shown in FIG. 3) of manufacturing the evaporator 200. The method 300 of manufacturing may be understood substantially from the constructional details of the evaporator 200 discussed above and shall be apparent to a person in the art after reading this specification.

[00 0] Reference is now made to FIG. 3 in view of the FIG. 2a through FIG. 2d. FIG. 3 shows the method 300 of manufacturing the evaporator 200 of the present subject matter. At block 301 the method provides the evaporator 200, in that, at block 311 the heat exchanger 237 is configured to receive liquid. Configuring the heat exchanger 237 at block 311 includes, at block 313, providing the feed tank 217 configured to receive the liquid and supplying the liquid to the heat exchanger 237. At block 321 a flash vessel 267 is coupled to the heat exchanger 237. The flash vessel 267 is configured to receive the liquid from the heat exchanger 237 and alter physical parameters of the liquid to cause phase separation of the liquid. At block 331 the humidifier 293 is provided. The humidifier 293 is configured to generate humidifier-vapours. The humidifier 293 is coupled to the flash vessel 267 to supply the humidifier-vapours to the flash vessel 267. At block 3 1 the compressor 277 is provided. The compressor 277 is configured to receive vapours from the flash vessel 267. In some options, the humidifier 293 may be directly coupled to the compressor 277 and the compressor 277 is configured to receive humidifier-vapours from the humidifier 293. The compressor 277 is configured to supply compressed-vapours to the heat exchanger 237. At block 315, the heat exchanger 237 is configured to thermally couple the liquid and the compressed-vapours to cause heat exchange between the liquid and the compressed-vapours to generate condensate of the compressed-vapours.

[00 1] At block 303, the pressure breaker 297 is provided. The pressure breaker 297 is configured to enable extraction of the condensate from the heat exchanger 237 while keeping the physical parameters of the liquid in the heat exchanger 237 substantially unaltered. In a further embodiment, the pressure breaker 297 is configured to maintain a pressure differential between humidifier 293 across elements of the evaporator 200. At block 305, the salt settler 2 9 is coupled to the heat exchanger 267. At this block the salt settler 2 9 may further be configured to receive the liquid from the heat exchanger 237 and filtering the liquid to extract salt crystals from the liquid. At block 307, the heat exchanger 237 and the flash vessel 267 are configured enable circulation of the liquid from the heat exchanger 237 to the flash vessel 267 and back. At block 309, the pre-heater 287 may be provided. The pre-heater 287 may be configured to pre-heat the liquid using the condensate prior to the liquid is fed to the heat exchanger 237.

[00 2] The subject matter is described herein may be susceptible to various modifications and alternative forms. The methods may be performed in manner and/or order different than what is explained. All modifications, equivalents, and alternatives also fall within the spirit and scope of the subject matter. The applicant herewith acknowledges the proprietary ownership of all the propriety terms of expression including trademarks/copyright etc. that may have been used by the applicant. Any omission in this respect is inadvertent and/or unintentional and without any malicious intention.