Process water treatment system and method of treating process water using a process water treatment system

Abstract

A process water treatment system is disclosed, comprising an evaporator for receiving and heating process water to generate a mixture of steams, a first purification unit for purifying the generated mixture of steams to obtain a purified mixture of steams, a condenser for condensing the purified mixture of steams to obtain a liquid condensate, a second purification unit for purifying the condensate to obtain a purified condensate, and a first compressor for generating a desired pressure in at least one portion of the system and delivering the purified mixture of steams from the first purification unit to the condenser. A method for treating process water is also disclosed.

Description

[0001] KMU LOFT Cleanwater SE - 1 - 30A-157 398

[0002] Process water treatment system and method of treating process water using a process water treatment system

[0003] The present disclosure is directed to a process water treatment system and to a method of treating process water using a process water treatment system.

[0004] The treatment of process water such as industrial wastewater enables a purification of contaminated liquids. Such contaminated liquids may arise, for example, as washing solutions in immersion, spray and ultrasonic cleaning plants, as process solutions in surface finishing processes, such as electroplating, pickling, anodizing, vibratory grinding, degreasing, phosphating, burnishing, powder coating or painting, or in drilling, cutting, grinding and drawing applications as well as in die casting. Liquids may be contaminated, for example, by solvents, oils, waxes, hydraulic fluids and / or coolants.

[0005] One technique of treating process water involves distillation. In this technique, contaminated water such as industrial wastewater is heated in an evaporation chamber under given pressure conditions. Water is thereby evaporated and can be provided to a condenser where it is liquefied. Depending on the temperature and pressure conditions in the evaporation chamber, substances having a boiling point higher than water tend to remain in the evaporation chamber in their liquid state. Thus, portions of the wastewater that are evaporated and then liquefied in the condenser have a lower concentration of the substances remaining in the evaporation chamber.

[0006] The present disclosure is directed to the problem of providing a process water treatment system suitable for purifying wastewaters containing different types of impurities. Further, the invention is directed to the problem of providing a method for treating process water containing different types of impurities using a process water distillation plant.

[0007] In case reference is made to a "top", a "bottom", "higher" or "lower" components herein, these references are understood as relating to the gravitational direction. That is, a "top" or "higher" part of a given component of the system is understood to be higher up for a human spectator compared with a "bottom" or "lower" part of the given component when the system is operably set up.

[0008] According to a first aspect, a process water treatment system is provided. KMU LOFT Cleanwater SE - 2 - 30A-157 398

[0009] The system may be configured to purify process water such as industrial wastewater or other contaminated fluids by removing impurities. The impurities may comprise substances having a boiling point between 0°C and 300°C at lOOOmBar pressure. The impurities may have a boiling point different from the boiling point of water at one or more predefined pressures (e.g., lying within 500mBar and 1500mBar). The impurities may comprise substances that are soluble in water and / or substances that are not soluble in water. The system may comprise a Mechanical Vapor Recompression, MVR, system or circuit.

[0010] The system comprises an evaporator, a first purification unit, a first compressor, a condenser and a second purification unit.

[0011] The evaporator is configured to, during operation of the system (e.g., when the system is activated, when the system is in operation, when the system is treating process water, when the system is in use and / or when the system is purifying process water), receive process water and heat the received process water to generate a mixture of steams. One may say that the evaporator is provided for heating process water to generate the mixture of steams. The evaporator may comprise a heating unit and a boiler having a sump, the heating unit configured to, during operation of the system, provide a predefined temperature (e.g., of the process water) within the boiler. The evaporator may be configured such that components of the process water in the boiler that are not dissolved in water and are heavier than water can collect in the sump. The sump may comprise an outlet (e.g., at a bottom portion of the sump and / or the boiler) configured and arranged such that the components collected in the sump can be discharged from (e.g., flow out of) the outlet. The boiler may comprise an inlet configured and arranged such that the process water can flow into the boiler through the inlet. The inlet may be arranged at a position higher than the outlet of the sump.

[0012] The first purification unit is configured to, during operation of the system, receive and purify the generated mixture of steams to obtain a purified mixture of steams. One may say that the first purification unit is provided for purifying the generated mixture of steams to obtain the purified mixture of steams. The purified mixture of steams may comprise a lower concentration of impurities than the process water received by the evaporator.

[0013] The first purification unit may be configured to, during operation of the system, purify the generated mixture of steams such that, when the generated mixture of KMU LOFT Cleanwater SE - 3 - 30A-157 398 steams comprises at least one first substance having a boiling point higher than water, the concentration of the at least one first substance in the purified mixture of steams is lower than in the generated mixture of steams. The first purification unit may be configured to, during operation of the system, when the generated mixture of steams comprises the at least one first substance, purify the generated mixture of steams by condensing at least a part of the at least one first substance out of the generated mixture of steams while maintaining (e.g., in gaseous form) a remainder of the generated mixture of steams as the purified mixture of steams. The first purification unit may be configured to, during operation of the system, purify the generated mixture of steams such that the purified mixture of steams consists of substances that maintained their gaseous phase during traveling from the evaporator to the first compressor.

[0014] The first purification unit may comprise or be configured as a steam washing unit. The first purification unit may be configured to, during operation of the system, purify the generated mixture of steams by putting the generated mixture of steams in contact with a washing liquid. The first purification unit may be configured such that, during operation of the system, a general flow direction of the generated mixture of steams within the first purification unit is opposite to a general flow direction of the washing liquid within the first purification unit.

[0015] The first purification unit may comprise or be configured as a packed (e.g., internal) distillation column. The first purification unit may comprise or be configured as a distillation column obtaining the purified mixture of steams from the generated mixture of steams. The first purification unit may comprise a first packing material. The first purification unit may be configured such that, during operation of the system, the generated mixture of steams flows through the first packing material. The first purification unit may be configured to, during operation of the system, supply the washing liquid to the first packing material to put the generated mixture of steams in contact with the washing liquid while the generated mixture of steams flows through the first packing material.

[0016] The condenser is configured to, during operation of the system, condense (e.g., liquefy) the purified mixture of steams to obtain a liquid condensate. One may say that the condenser is provided for condensing the purified mixture of steams to obtain the liquid condensate. The liquid condensate may consist of the same components as the purified mixture of steams. KMU LOFT Cleanwater SE - 4 - 30A-157 398

[0017] The condenser and the evaporator may form a main heat exchanger configured to (e.g., during operation of the system) facilitate a heat exchange between the purified mixture of steams and the process water received by the evaporator. The main heat exchanger may also be referred to as second heat exchanger herein. The main heat exchanger may be configured to (e.g., during operation of the system) transfer thermal energy from the purified mixture of steams to the process water received by the evaporator, to thereby heat up the process water received by the evaporator (e.g., to generate the mixture of steams). The main heat exchanger may be configured to (e.g., during operation of the system) transfer thermal energy from the purified mixture of steams to the process water received by the evaporator, to thereby cool down the purified mixture of steams within the condenser (e.g., to obtain the liquid condensate). The condenser may be arranged at or within the evaporator, for example within the boiler of the evaporator.

[0018] The first compressor is configured to, during operation of the system, generate a desired (e.g., under- or over-) pressure in at least one portion of the system and deliver the purified mixture of steams from the first purification unit to the condenser. One may say that the first compressor is provided for generating the desired (e.g., first) pressure in the at least one portion of the system and for delivering the purified mixture of steams from the first purification unit to the condenser.

[0019] The at least one portion of the system may comprise (i) a portion of the evaporator configured to (e.g., during operation of the system) house the generated mixture of steams (e.g., an upper portion of the boiler or a middle portion of the boiler) and / or (ii) a portion of the first purification unit (e.g., an upper portion of the first purification unit) configured to (e.g., during operation of the system) house the purified mixture of steams.

[0020] The first compressor may be arranged in a fluid path between the first purification unit and the condenser. The first compressor may be configured to, during operation of the system, provide a higher pressure in the condenser than in the first purification unit and / or the evaporator (e.g. the boiler). The first compressor may be configured to, during operation of the system, compress the purified mixture of steams and deliver the compressed purified mixture of steams to the condenser. The first compressor may be configured to, during operation of the system, heat the purified mixture of steams by compressing the purified mixture of steams (e.g., before delivering the purified mixture of steams to the condenser). KMU LOFT Cleanwater SE - 5 - 30A-157 398

[0021] The evaporator, the first compressor and the condenser may form an MVR system or circuit. The main heat exchanger and the compressor may form the MVR system or circuit. The first purification unit may comprise or be configured as an internal distillation column of the MVR system or circuit.

[0022] The second purification unit is configured to, during operation of the system, receive and purify the condensate to obtain a purified condensate. One may say that the second purification unit is provided for purifying the condensate to obtain the purified condensate. The purified condensate may comprise a lower concentration of impurities than the condensate.

[0023] The second purification unit may be configured to, during operation of the system, purify the condensate such that, when the condensate comprises at least one second substance having a boiling point lower than water, the concentration of the at least one second substance in the purified condensate is lower than in the condensate. The second purification unit may be configured to, during operation of the system, when the condensate comprises the at least one second substance, purify the condensate by evaporating or stripping at least a part of the at least one second substance out of the condensate while maintaining (e.g., in liquid form) a remainder of the condensate as the purified condensate. The second purification unit may be configured to, during operation of the system, purify the condensate such that the purified condensate consists of substances that maintained their liquid phase during traveling from the condenser to an outlet of the second purification unit.

[0024] The second purification unit may comprise or be configured as an evaporator unit or stripping unit. The second purification unit may be configured to, during operation of the system, purify the condensate by putting the condensate in contact with a washing gas. The second purification unit may be configured such that, during operation of the system, a general flow direction of the condensate within the second purification unit is opposite to a general flow direction of the washing gas within the second purification unit.

[0025] The second purification unit may comprise or be configured as a packed (e.g., external) distillation column. The second purification unit may comprise or be configured as an external distillation column of the MVR system or circuit. The second purification unit may comprise or be configured as a distillation column yielding the purified condensate as bottom product. The second purification unit may comprise a second packing material. The second purification unit may be configured such that, during operation of the system, the condensate flows through the second KMU LOFT Cleanwater SE - 6 - 30A-157 398 packing material. The second purification unit may be configured to, during operation of the system, supply the washing gas to the second packing material to put the condensate in contact with the washing gas while the condensate flows through the second packing material. The second packing material may differ from the first packing material. In another variant, the second packing material is similar to the first packing material.

[0026] The second purification unit may comprise one or more of: an upper inlet, an upper outlet, a lower inlet, and a lower outlet. The second purification unit may be configured to, during operation of the system, receive the condensate via the upper inlet. The second purification unit may be configured to, during operation of the system, receive the washing gas via the lower inlet. The second purification unit may be configured to, during operation of the system, dispose of or expel the purified condensate via the lower outlet. The second purification unit may be configured to, during operation of the system, dispose of or expel the at least one second substance via the upper outlet.

[0027] The system may be configured such that the washing liquid comprises at least a part of the condensate and / or at least a part of the purified condensate. The washing liquid may consist of the condensate and / or the purified condensate.

[0028] The system may further comprise a second compressor configured to, during operation of the system, generate a desired (e.g., under-) pressure in at least one portion of the second purification unit. The second compressor may be fluidly connected to the upper outlet of the second purification unit. The second compressor may be configured to, during operation of the system, deliver gaseous components extracted from the second purification unit to an outlet of the second compressor. The second compressor may be configured to, during operation of the system, deliver the at least one second substance from the second purification unit to the outlet of the second compressor.

[0029] The system may further comprise a first heat exchanger configured to, during operation of the system, enable or facilitate a heat exchange between the purified condensate and the process water (e.g., before the process water is received by the evaporator). The first heat exchanger may also be referred to as pre-heat exchanger herein. The first heat exchanger may be configured to, during operation of the system, heat the process water by transferring heat energy or facilitating heat transfer from the purified condensate to the process water, before the process water is received by the evaporator. The first heat exchanger may be configured to, during KMU LOFT Cleanwater SE - 7 - 30A-157 398 operation of the system, cool the purified condensate by transferring heat energy or facilitating heat transfer from the purified condensate to the process water, before the process water is received by the evaporator. The washing liquid may comprise a portion of the cooled purified condensate and / or a portion of the purified condensate before being cooled by the first heat exchanger.

[0030] The system may further comprise a second condenser configured to, during operation of the system, condense (e.g., the) gaseous components (e.g., the at least one second substance) extracted from the second purification unit. The second condenser may be configured to, during operation of the system, condense the at least one second substance received from the second purification unit (e.g., via the second compressor). The outlet of the second compressor may be connected to the second condenser. The second compressor may be configured to, during operation of the system, deliver the at least one second substance from the second purification unit to the second condenser. The second condenser may be part of a third heat exchanger.

[0031] The evaporator may be configured to, during operation of the system, heat the process water to a first predefined temperature. The first compressor may be configured to, during operation of the system, provide a first predefined pressure in the at least one portion of the system (e.g., in the portion of the evaporator configured to (e.g., during operation of the system) house the generated mixture of steams). The first temperature and the first pressure may be selected such that water will evaporate when heated to the first temperature under the first pressure. The first temperature may correspond to the boiling point of water at the first pressure.

[0032] The first predefined temperature may be > 10°C. The first predefined temperature may be < 300°C. The first predefined temperature may be in a range of 20-200°C, for example between 50-150°C. The first predefined temperature may be in a range between 60-100°C, for example 70-90°C or 80-90°C. The first predefined temperature may be 86°C. Other values and ranges of the first predefined temperature are possible. For example, the first predefined temperature may deviate from the aforementioned values and / or ranges by ± x°C, with x being selected from one of 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15 or 20.

[0033] The first predefined pressure may be > lOOmBar. The first predefined pressure may be < 3000mBar. The first predefined pressure may be in a range of 200-2000mBar, for example between 400-1000mBar. The first predefined pressure may be in a KMU LOFT Cleanwater SE - 8 - 30A-157 398 range between 450-900mBar, for example 500mBar-800mBar or 500mBar-700mBar. The first predefined pressure may be 600mBar. Other values and ranges of the first predefined pressure are possible. For example, the first predefined pressure may deviate from the aforementioned values and / or ranges by ± ymBar, with / being selected from one of 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150 or 200.

[0034] The first compressor may be configured to, during operation of the system, compress the purified mixture of steams such that the compressed purified mixture of steams has a second predefined temperature and a second predefined pressure (e.g., before being delivered to the condenser). The second predefined temperature may be higher than the first predefined temperature. The second predefined pressure may be higher than the first predefined pressure. The second predefined temperature and the second predefined pressure may define superheated water vapor conditions. In other words, the second predefined temperature and the second predefined pressure may be selected such that water will evaporate when heated to the second predefined temperature under the second predefined pressure. The second predefined temperature may correspond to or lie above the boiling point of water at the second predefined pressure.

[0035] The second predefined temperature may be > 15°C. The second predefined temperature may be > 100°C. The second predefined temperature may be < 350°C. The second predefined temperature may be in a range of 25-230°C, for example between 60-200°C. The second predefined temperature may be in a range between 80-180°C, for example 90-170°C or 100-150°C. The second predefined temperature may be 120°C. Other values and ranges of the second predefined temperature are possible. For example, the second predefined temperature may deviate from the aforementioned values and / or ranges by ± z°C, with z being selected from one of 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15 or 20.

[0036] The second predefined pressure may be > 400mBar. The second predefined pressure may be < 3000mBar. The second predefined pressure may be in a range of 500-2000mBar, for example between 600-1500mBar. The second predefined pressure may be in a range between 700-1400mBar, for example 800mBar- 1200mBar or 900mBar-1100mBar. The second predefined pressure may be lOOOmBar. Other values and ranges of the second predefined pressure are possible. For example, the second predefined pressure may deviate from the aforementioned values and / or ranges by ± p mBar, with p being selected from one of 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150 or 200. KMU LOFT Cleanwater SE - 9 - 30A-157 398

[0037] The condenser may be configured to, during operation of the system, enable or effect a temperature change of the (e.g., compressed) purified mixture of steams (e.g., received by the condenser) to a third predefined temperature and / or a pressure change of the (e.g., compressed) purified mixture of steams (e.g., received by the condenser) to a third predefined pressure. The third predefined temperature may be lower than the second predefined temperature. The third predefined temperature may be equal to or higher than the first predefined temperature. The third predefined pressure may be equal to or lower than the second predefined pressure. In another variant, the third predefined pressure may be higher than the second predefined pressure. The third predefined temperature and the third predefined pressure may be selected such that water will not evaporate when heated to the third predefined temperature under the third predefined pressure. The third predefined temperature may correspond to or lie below the boiling point of water at the third predefined pressure. The condenser may comprise an input valve and / or an output valve to control a fluid flow into and / or out of the condenser. By controlling the fluid flow into and / or out of the condenser, the third predefined temperature of the condensate and / or the third predefined pressure may be provided.

[0038] The third predefined temperature may be > 13°C. The third predefined temperature may be < 100°C. The third predefined temperature may be < 320°C. The third predefined temperature may be in a range of 20-210°C, for example between 50- 180°C. The third predefined temperature may be in a range between 60-150°C, for example 70-140°C, 80-100°C or 90-100°C. The third predefined temperature may be in a range between 95-98°C. The third predefined temperature may be 97°C. Other values and ranges of the third predefined temperature are possible. For example, the third predefined temperature may deviate from the aforementioned values and / or ranges by ± q°C, with q being selected from one of 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15 or 20.

[0039] The third predefined pressure may be > 400mBar. The third predefined pressure may be < 3000mBar. The third predefined pressure may be in a range of 500- 2000mBar, for example between 600-1500mBar. The third predefined pressure may be in a range between 700-1400mBar, for example 800mBar-1200mBar or 900mBar- HOOmBar. The third predefined pressure may be lOOOmBar. Other values and ranges of the third predefined pressure are possible. For example, the third predefined pressure may deviate from the aforementioned values and / or ranges by ± i / m Bar, with PI / being selected from one of 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150 or 200. KMU LOFT Cleanwater SE - 10 - 30A-157 398

[0040] The second compressor may be configured to, during operation of the system, ensure a fourth predefined pressure in at least a portion of the second purification unit. The fourth predefined pressure may be lower than the third predefined pressure and / or the second predefined pressure. The fourth predefined pressure may be higher than the first predefined pressure. The fourth predefined pressure may be selected such that water (e.g., having the third predefined temperature) will not evaporate in the second purification unit when under the fourth predefined pressure. The third predefined temperature may correspond to or lie below the boiling point of water at the fourth predefined pressure. The fourth predefined pressure may be selected such that the at least one second substance (e.g., having the third predefined temperature) will evaporate in the second purification unit when under the fourth predefined pressure. The third predefined temperature may correspond to or lie above the boiling point of the at least one second substance at the fourth predefined pressure. The condensate may not be heated within the second purification unit. The condensate may maintain or cool down from the third predefined temperature within the second purification unit.

[0041] The fourth predefined pressure may be > 380mBar. The fourth predefined pressure may be < 3000mBar. The fourth predefined pressure may be in a range of 450- 1950mBar, for example between 550-1450mBar. The fourth predefined pressure may be in a range between 650-1350mBar, for example 750mBar-1100mBar or 800mBar- lOOOmBar. The fourth predefined pressure may be in a range between 800mBar- 980mBar, for example between 900m Bar-975m Bar or between 930-970mBar. The fourth predefined pressure may be 950mBar. Other values and ranges of the fourth predefined pressure are possible. For example, the fourth predefined pressure may deviate from the aforementioned values and / or ranges by ± h mBar, with h being selected from one of 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150 or 200.

[0042] The system may comprise one or more temperature sensors, each being arranged and configured to (e.g., during operation of the system) provide temperature measurements at a respective predefined position of the system. The system or components thereof (e.g., the evaporator, the first compressor, the condenser and / or the second compressor) may be configured to (e.g., during operation of the system) control a temperature (e.g., at the respective predefined position) based on the temperature measurement(s). For example, a temperature sensor may be provided that is configured to, at least during operation of the system, measure a temperature of the process water received by the evaporator. A temperature sensor KMU LOFT Cleanwater SE - 11 - 30A-157 398 may be provided that is configured to, at least during operation of the system, measure a temperature of the generated and / or the purified mixture of steams. A temperature sensor may be provided that is configured to, during operation of the system, measure a temperature of the compressed purified mixture of steams. A temperature sensor may be provided that is configured to, during operation of the system, measure a temperature of condensate.

[0043] The system may comprise one or more pressure sensors, each being arranged and configured to (e.g., at least during operation of the system) provide pressure measurements at a respective predefined position of the system. The system or components thereof (e.g., the first compressor and / or the second compressor) may be configured to (e.g., at least during operation of the system) control a pressure (e.g., at the respective predefined position) based on the pressure measurement(s). For example, a pressure sensor may be provided that is configured to, during operation of the system, measure a pressure of a portion of the evaporator holding the generated mixture of steams and / or of a portion of the first purification unit holding the purified mixture of steams. A pressure sensor may be provided that is configured to, during operation of the system, measure a pressure of the compressed purified mixture of steams. A pressure sensor may be provided that is configured to, during operation of the system, measure a pressure of a portion of the second purification unit holding the at least one second substance in gaseous form.

[0044] The system may further comprise a control unit configured to control operation of (e.g., components of) the system. The control unit may be configured to (e.g., at least during operation of the system) control operation of at least one component of the system selected from: the evaporator, the first purification unit, the first compressor, the condenser, the second purification unit, the second compressor, the second condenser, the first heat exchanger, the second exchanger, the third heat exchanger, the one or more pressure sensors, and the one or more temperature sensors. The control unit may be configured to perform the method according to the second aspect (e.g., using the system or components thereof).

[0045] According to a second aspect, a method of treating process water using a process water treatment system (e.g., the system according to the first aspect) comprising an evaporator, a first purification unit, a first compressor, a condenser and a second purification unit is provided. The features described for the system according to the first aspect may similarly apply to the method according to the second aspect. As far as a component of the system according to the first aspect is configured to perform a KMU LOFT Cleanwater SE - 12 - 30A-157 398 certain function, said function may be a step of the method according to the second aspect.

[0046] The method comprises generating a desired pressure in at least one portion of the system, using the first compressor.

[0047] The method further comprises at least partially evaporating process water, using the evaporator, to generate a mixture of steams.

[0048] The method comprises purifying the generated mixture of steams, using the first purification unit, to obtain a purified mixture of steams.

[0049] The step of purifying the generated mixture of steams may be performed such that, when the generated mixture of steams comprises at least one first substance having a boiling point higher than water, the concentration of the at least one first substance in the purified mixture of steams is lower than in the generated mixture of steams.

[0050] The step of purifying the generated mixture of steams may comprise, when the generated mixture of steams comprises the at least one first substance, condensing at least a part of the at least one first substance out of the generated mixture of steams while maintaining a remainder of the generated mixture of steams as the purified mixture of steams.

[0051] The step of purifying the generated mixture of steams may comprise putting the generated mixture of steams in contact with a washing liquid.

[0052] The washing liquid may comprise at least a part of the condensate and / or at least a part of the purified condensate.

[0053] The first purification unit may comprise a (e.g., the) first packing material and during the step of purifying the generated mixture of steams, the generated mixture of steams may flow through the first packing material.

[0054] The method comprises delivering the purified mixture of steams to the condenser, using the first compressor.

[0055] The method comprises condensing the purified mixture of steams, using the condenser, to obtain a liquid condensate. KMU LOFT Cleanwater SE - 13 - 30A-157 398

[0056] The method further comprises purifying the condensate, using the second purification unit, to obtain a purified condensate.

[0057] The step of purifying the condensate may be performed such that, when the condensate comprises at least one second substance having a boiling point lower than water, the concentration of the at least one second substance in the purified condensate is lower than in the condensate.

[0058] The step of purifying the condensate may comprise, when the generated mixture of steams comprises the at least one second substance, evaporating at least a part of the at least one second substance out of the condensate while maintaining a remainder of the condensate as the purified condensate.

[0059] The step of purifying the condensate may comprise putting the condensate in contact with a washing gas.

[0060] The second purification unit may comprise a (e.g., the) second packing material and during the step of purifying the condensate, the condensate may flow through the second packing material.

[0061] The at least one portion of the system may comprise (i) a portion of the evaporator configured to house the generated mixture of steams and / or (ii) a portion of the first purification unit configured to house the purified mixture of steams.

[0062] The method may further comprise at least one of the following steps: compressing the purified mixture of steams before delivering (e.g., pumping, blowing, guiding or providing) the purified mixture of steams to the condenser; exchanging heat between the purified condensate and the process water; generating a desired pressure in at least one portion of the second purification unit; condensing gaseous components extracted from the second purification unit; obtaining temperature measurements at one or more positions of the system; and obtaining pressure measurements at one or more positions of the system.

[0063] In a first variant covered by the present disclosure but currently not reflected in the claims, the system according to the first aspect does not necessarily comprise the first purification unit. Similarly, in the first variant, the method according to the KMU LOFT Cleanwater SE - 14 - 30A-157 398 second aspect does not necessarily comprise the step of purifying the generated mixture of steams, using the first purification unit, to obtain a purified mixture of steams. In the first variant, the generated mixture of steams may be delivered by the first compressor to the condenser. The at least one first substance may be partially evaporated or dragged upwards by the generated mixture of steams toward the first compressor. Thus, the first variant may yield a condensate that contains a higher concentration of the at least one first substance than the technique according to the first and second aspect described herein above. On the other hand, the first variant may minimize the number of components needed and reduce the size of the system.

[0064] In a second variant covered by the present disclosure but currently not reflected in the claims, the system according to the first aspect does not necessarily comprise the second purification unit. Similarly, in the second variant, the method according to the second aspect does not necessarily comprise the step of purifying the condensate, using the second purification unit, to obtain a purified condensate. In the second variant, the condensate may correspond to the condensate obtained by condensing the purified mixture of steams. The at least one second substance may still be present in the condensate. Thus, the second variant may yield condensate that contains a higher concentration of the at least one second substance than the technique according to the first and second aspect described herein above. On the other hand, the second variant may minimize the number of components needed and reduce the size of the system.

[0065] Preferred embodiments are explained in more detail below with reference to the drawings, wherein

[0066] Fig. 1 shows a first exemplary process water treatment system in accordance with the present disclosure;

[0067] Fig. 2 shows a second exemplary process water treatment system in accordance with the present disclosure; and

[0068] Fig. 3 shows a flowchart of an exemplary method in accordance with the present disclosure.

[0069] Fig. 1 shows a first exemplary process water treatment system 100. The system 100 comprises a pre-heat exchanger 2, also referred to as first heat exchanger herein, an evaporator 4a, a first purification unit 6, a first compressor 8, a condenser 10, a second purification unit 12, a second compressor 14 and a second condenser 15. KMU LOFT Cleanwater SE - 15 - 30A-157 398

[0070] During operation of the system 100, process water 14 comprising impurities such as wax, solvents, organic molecules or the like flows into the pre-heat exchanger 2, where it is pre-heated by excess heat provided by the purified condensate 16. The process water 14 does not come into direct contact with the purified condensate 16 within the pre-heat exchanger 2, i.e., the two fluids do not mix with one another in the pre-heat exchanger 2.

[0071] The pre-heated process water 14 then flows into a boiler or evaporation chamber 20a of the evaporator 4a through an inlet 22. The inlet 22 is provided above a sump 24a of the boiler 20a. The evaporator 4a and the condenser 10 form a main heat exchanger of a MVR circuit 26 comprising the evaporator 4a, the first purification unit 6, the first compressor 8 and the condenser 10. The pre-heated process water 14 is heated inside the boiler 20a by excess heat of the purified mixture of steams 28 flowing through the condenser 10. The evaporator 4a may comprise an additional heat source. In this manner, the pre-heated process water 14 is heated to a first predefined temperature within the boiler 20a, for example a temperature of 86°C. At the same time, the first compressor 8 of the MVR circuit 26 provides a desired, first predefined pressure in a gas-holding portion 21 of the boiler 20a, for example a pressure of 600mBar. The first predefined temperature and the first predefined pressure ensure that the pre-heated process water 14 in the boiler 20a reaches the boiling point of water. In this way, a mixture of steams 28 is generated by evaporating at least some substances contained in the process water 14, namely H2O and any substance having a boiling point lower than that of water at the first predefined pressure. The generated mixture of steams 28 travels from the upper, gas-holding portion 21 of the boiler 20a through a steam outlet 30 into the first purification unit 6. The movement of the generated mixture of steams 28 from the boiler 20a into the first purification unit 6 is provided by the first compressor 8 which draws or sucks the steams 28 in the direction indicated by the arrow between the evaporator 4a and the first purification unit 6. Substances heavier than water collect in the sump 24a and exit the evaporator 4a through an outlet 31 in a bottom of the sump 24a, e.g., if a process water treatment cycle is finished.

[0072] The first purification unit 6 is configured as a packed column but may not comprise a heat source. That is, the generated mixture of steams 28 may maintain its temperature inside the first purification unit 6 or even be cooled down. In the first purification unit 6, the mixture of steams 28 is washed by a washing liquid 31. The washing liquid 31 may be the purified condensate 16 exiting the pre-heat exchanger 2 or the condensate 32 entering the second purification unit 6. In the illustrated KMU LOFT Cleanwater SE - 16 - 30A-157 398 variant, the washing liquid 1 corresponds to the purified condensate 16, as indicated by the connections designated with numeral "1". The first purification unit 6 washes out first substances (also referred to as heavy substances herein) contained in the process water 14 that have a higher boiling point than water under the first predefined pressure. Such substances may nevertheless be present in the mixture of steams 28, as they may be dragged (e.g., in gaseous, liquid or solid form) by evaporated steams from the boiler 20a into the first purification unit 6. The generated mixture of steams 28, potentially including the first substance(s), flows through a first packing material 36 inside the first purification unit 6. The washing liquid 31 runs through the packing material 36 in the opposite direction. This ensures that the first substances are reliably removed from the generated mixture of steams 28. The washed steams 38, also referred to as purified (e.g., mixture of) steams herein, exit the first purification unit 6 via an outlet 40 in an upper portion 41 of the first purification unit 6. Any liquid substances, such as the washing liquid 31 and first substance(s) washed out of the generated mixture of steams 28, collect in a bottom portion 42 of the first purification unit 6 and flow back into the boiler 20a.

[0073] The purified mixture of steams 38 is compressed by the first compressor 8 to a second predefined pressure (e.g., a pressure of lOOOmBar) that is higher than the first predefined pressure. Due to the compression, the purified mixture of steams 38 heats up to a second (e.g., predefined) temperature, for example a temperature of 120°C. The compressed purified mixture of steams 38 is then delivered to the condenser 10. Inside the condenser 10, the compressed purified mixture of steams 38 transfers heat to the pre-heated process water 14 in the boiler 20a. Thereby, the compressed mixture of steams 38 cools down (e.g., to 95-98°C) and becomes a liquid condensate 32. The main heat exchanger formed by the evaporator 4a and the condenser 10 minimizes the heating energy required to provide the first predefined temperature in the boiler 20a.

[0074] The liquid condensate 32 may still comprise some impurities, for example second substances (also referred to as light substances herein) that have a boiling point lower than the boiling point of water at the first predefined pressure. To remove such light substances, the second purification unit 12 is provided.

[0075] The liquid condensate 32 flows through an upper inlet 42 into the second purification unit 12. At the same time, a washing gas 44 (e.g., air, nitrogen or another inert and / or inflammable gas) flows into the second purification unit 12 through a lower inlet 46. The second purification unit 12 comprises a second packing material 50. The liquid condensate 32 flows through the packing material 50 while the washing gas 44 KMU LOFT Cleanwater SE - 17 - 30A-157 398 travels through the packing material 50 in the opposite direction. The second compressor 14 provides a pressure (e.g., 950mBar) within a gas-holding portion 52 of the second purification unit 12, which pressure is a bit higher than the pressure required to evaporate water from the liquid condensate 32 (e.g., having a temperature of 95-98°C). This minimizes the amount of water evaporated from the liquid condensate 32 within the second purification unit 12, while ensuring that any light substances transition into the gas phase. The light substances are then sucked out of the second purification unit 12 by the second compressor 14 through an upper outlet 54 and flow into the second condenser 15 where they are liquefied into liquid light substances 56 using a coolant 58. The remainder of the condensate, i.e., the purified condensate 16, flows out of the second purification unit 12 through a lower outlet 60, and into the pre-heat exchanger 2 where it pre-heats the process water 14.

[0076] The system 100 further comprises one or more temperature sensors 62, each being arranged and configured to provide temperature measurements at a respective predefined position of the system, and one or more pressure sensors 64, each being arranged and configured to provide pressure measurements at a respective predefined position of the system. The system 100 further comprises a control unit 66 configured to control operation of (e.g., at least some or all components of) the system 100. The control unit 66 may be communicatively coupled with one or more of the components of the system 100, for example with the sensors 62, 64, a heat source of the evaporator 4a, the compressors 8, 14 and entities (e.g., valves, pumps or the like) controlling flow of fluids inside the system 100.

[0077] The system 200 shown in Fig. 2 differs from the system of Fig. 1 in the configuration of the evaporator. The evaporator 4b of the system 200 is a forced circulation evaporator, whereas the evaporator 4a of the system 100 is a natural circulation evaporator. While the evaporator 4a comprises the boiler 20a having sump 24a, the evaporator 4b comprises the boiler 20b having sump 24b. Both variants fall within the scope of the present disclosure.

[0078] In the evaporator 4a shown in Fig. 1, the pre-heated process water 14, upon flowing into the boiler 20a, is directly heated and at least partially evaporated by coming into contact with an interior surface of the condenser 10. On the other hand, in the evaporator 4b shown in Fig. 2, the pre-heated process water 14 is supplied into a portion 25 of the boiler 20b where it does not come into contact with an interior surface of the condenser 10. The process water collects in the sump 24b and is then supplied to another portion of the boiler 10b, where it comes into contact with the KMU LOFT Cleanwater SE - 18 - 30A-157 398 interior surface of the condenser 10. Both variants of the evaporator generate a mixture of steams 28 that is directed into the first purification unit.

[0079] Fig. 3 shows a method 300 of treating process water 14 using the system 100 or the system 200. As described with reference to Figs. 1 and 2, a desired first predefined pressure is provided in a portion of the evaporator 4a, 4b, namely a portion configured to hold the generated mixture of steams 28 (step 302). The process water 14 in the evaporator 4a, 4b may be heated to a temperature of around 86°C. The process water 14 in contact with the (e.g., gas-holding) portion of the evaporator 4a, 4b having the desired (under-)pressure, for example 600mBar, is at least partially evaporated to generate the mixture of steams 28 (step 304). The generated mixture of steams 28 is then purified in the first purification unit 6 to obtain a purified mixture of steams 38 (step 306). The purified mixture of steams 38 is then delivered by the first compressor 8 into the condenser 10 (step 308). The compressor 8 thereby compresses the purified mixture of steams 28 to a higher pressure (e.g., lOOOmBar) whereby the purified mixture of steams 28 heats up, for example to a temperature of around 120°C. The compressed purified mixture of steams is directed into the condenser 10, inside of which it cools down by transferring heat energy to the liquid in the evaporator 4a, 4b that is in contact with an interior surface of the condenser 10. Thus, the compressed purified mixture of steams condenses and a liquid condensate 32 is obtained (step 310). The liquid condensate 32 is then purified to obtain a purified condensate 16 (step 312) using the second purification unit 12.

[0080] More generally speaking, the present disclosure provides for a technique in which process water 14 is first placed under a first predefined temperature and pressure condition selected to evaporate water from the process water 14, the generated mixture of steams is washed to minimize the amount of heavy substances therein and the purified mixture is then purified further by placing it under another (e.g., third) predefined temperature and pressure condition to evaporate light substances therefrom. That is, the process water 14 undergoes a plurality of temperature / pressure conditions to get rid of light and heavy substances.

[0081] The present disclosure generally provides a system (e.g., 100, 200) and a method (e.g., 300) using MVR for water treatment. In MVR, two currents are produced: A concentrate (e.g., collected in the sump 24a, 24b) and a distillate (e.g., the generated mixture of steams 28). The MVR process is started and maintained by means of a blower (e.g., the first compressor 8) which generates vacuum (e.g., the first predefined pressure) in the distillation chamber (e.g., the boiler 20a, 20b) and KMU LOFT Cleanwater SE - 19 - 30A-157 398 compresses the steam produced in the evaporation (when using the first purification unit 6, compressing the purified mixture of steams 38, when not using the first purification unit 6, compressing the generated mixture of steams 28). The thermally charged steam (e.g., heated and compressed (e.g., purified) mixture of steams 28 / 38) therefore gives back the containing energy during condensation (e.g., in the condenser 10). The formed delta temperature between the evaporation chamber (e.g., the boiler 20a, 20b) and the condensation chamber (e.g., the condenser 10) is the driving force maintaining the energy flow, therefore the energy recovery. Distillate (e.g., the generated mixture of steams 28) may contain traces of organic pollutants, due to steam transport / dragging as well as a lower boiling point of the (e.g., second) substance compared with water. These organic pollutants are therefore responsible a diminished quality of the distillate and may affect reuse of water and the effect and performance of post processes for water conditioning. One approach of process water treatment disclosed herein is based on the boiling point differences of the (e.g. first and second) substances relative to water, including light substances (e.g., the at least one second substance) with boiling point lower than water and heavy substances (e.g., the at least one first substance) with boiling point higher than the boiling point of water. During the MVR process the mixture of steams (e.g., 28) produced and loaded with light and heavy substances is going through different temperature / pressure conditions during its path in the system. Wet steam (content of both light and heavy substances) at 86°C and 600mBar is produced in the evaporator (e.g., 4a, 4b), and this steam goes up to a separation unit (e.g., the first purification unit 6) by the effects of the sucking power of the blower (e.g., the first compressor 8). At this stage, putting the mixture of steams in contact with a falling liquid (e.g., washing liquid 31 such as condensate 32 or purified condensate 16) in a (e.g., first) packing material (e.g., 36) with sufficient surface will have the effect of condensing the so-called heavy substances which have boiling point higher than water. Washed steam then goes to the blower (e.g., the first compressor 8) where the temperature and the pressure change to 120°C and lOOOmBars. At this stage superheated steam is present downstream of the blower, which includes water vapor and light substances. In the condensation chamber (outer part of the main heat exchanger) this mixture gives back heat energy and condensates by changing the phase to liquid at a temperature between 95° to 98°C. This liquid condensate (e.g., 32) is guided through a (e.g., second) packing material (e.g., 50) and the pressure is slightly changed to 950mBars to remove the light substances (e.g., within the second purification unit 12). By applying this combination of processes, a distillate (e.g., the purified condensate 16) with a higher quality (e.g., containing fewer polluting substances or contaminations) can be produced. KMU LOFT Cleanwater SE - 20 - 30A-157 398

[0082] It is to be understood that the system 100 and the system 200 may comprise more features or fewer features than described with reference to the Figures. The system 100 and / or the system 200 may correspond to or be configured similar as the system according to the first aspect. Similarly, the method 300 may comprise more features or fewer features than described with reference to the Figures. The method 300 may correspond to or comprise the steps of the method according to the second aspect, other modifications, combinations and adaptions of the systems and methods described herein are possible. For example, a system may comprise a sequential arrangement of a plurality of evaporators 4a or 4b and first purification units 6 as part of the MVR circuit 26. As another example, the first purification unit 6 may be configured as a distillation column having a plurality of separation levels or steps. It may also be possible to adapt the systems and methods described herein for treating other types of contaminated fluids (e.g., non-aqueous liquids), so instead of wastewater, a waste solution of organic and / or inorganic fluids may be treated. In this case, the purified liquid to be obtained as the purified condensate defines the temperature and pressure conditions. The purified liquid should be evaporated in the evaporator 4a, 4b and condensed in the condenser 10, and not be evaporated in the second purification unit 12. In this scenario, the term "process water" used herein may be replaced with the term "contaminated substance of interest" and the term "water" may be replaced with "substance of interest". The substance of interest may be an organic solvent such as an alcohol, an oil or the like. The substance of interest may be a main component of a liquid used in an industrial process. In the contaminated substance of interest, the contaminations (e.g., first and / or second substance) may have a lower concentration compared with the substance of interest. Further modifications and advantages of the techniques disclosed herein may become apparent to those skilled in the art.

Claims

KMU LOFT Cleanwater SE - 21 - 30A-157 398Claims1. A process water treatment system (100; 200), comprising: an evaporator (4a; 4b) configured to, during operation of the system, receive process water (14) and heat the received process water (14) to generate a mixture of steams (28); a first purification unit (6) configured to, during operation of the system, receive and purify the generated mixture of steams (28) to obtain a purified mixture of steams (38); a condenser (10) configured to, during operation of the system, condense the purified mixture of steams (38) to obtain a liquid condensate (32); a second purification unit (12) configured to, during operation of the system, receive and purify the condensate (32) to obtain a purified condensate (16); and a first compressor (8) configured to, during operation of the system, generate a desired pressure in at least one portion of the system (100; 200) and deliver the purified mixture of steams (38) from the first purification unit (6) to the condenser (10).

2. The system of claim 1, wherein the first purification unit (6) is configured to, during operation of the system, purify the generated mixture of steams (28) such that, when the generated mixture of steams (28) comprises at least one first substance having a boiling point higher than water, the concentration of the at least one first substance in the purified mixture of steams (38) is lower than in the generated mixture of steams (28).

3. The system of claim 2, wherein the first purification unit (6) is configured to, during operation of the system, when the generated mixture of steams (28) comprises the at least one first substance, purify the generated mixture of steams (28) by condensing at least a part of the at least one first substance out of the generated mixture of steams (28) while maintaining a remainder of the generated mixture of steams as the purified mixture of steams (38).

4. The system of any one of claims 1 to 3, wherein the second purification unit (12) is configured to, during operation of the system, purify the condensate (32) such that, when the condensate (32) comprises at least one second substance having a boiling point lower than water, the concentration of the at least one second substance in the purified condensate (16) is lower than in the condensate (32).KMU LOFT Cleanwater SE - 22 - 30A-157 3985. The system of claim 4, wherein the second purification unit (12) is configured to, during operation of the system, when the condensate (32) comprises the at least one second substance, purify the condensate (32) by evaporating at least a part of the at least one second substance out of the condensate (32) while maintaining a remainder of the condensate as the purified condensate (16).

6. The system of any one of claims 1 to 5, wherein the first purification unit (6) is configured to, during operation of the system, purify the generated mixture of steams (28) by putting the generated mixture of steams (28) in contact with a washing liquid (31).

7. The system of claim 6, configured such that the washing liquid (31) comprises at least a part of the condensate (32) and / or at least a part of the purified condensate (16).

8. The system of any one of claims 1 to 7, wherein the second purification unit (12) is configured to, during operation of the system, purify the condensate (32) by putting the condensate (32) in contact with a washing gas (44).

9. The system of any one of claims 1 to 8, wherein the first purification unit (6) comprises a first packing material (36) and is configured such that, during operation of the system, the generated mixture of steams (28) flows through the first packing material (36); and / or wherein the second purification unit (12) comprises a second packing material (50) and is configured such that, during operation of the system, the condensate (32) flows through the second packing material (50).

10. The system of any one of claims 1 to 9, wherein the at least one portion of the system comprises (i) a portion of the evaporator (4a; 4b) configured to house the generated mixture of steams (28) and / or (ii) a portion of the first purification unit (6) configured to house the purified mixture of steams (38).

11. The system of any one of claims 1 to 10, further comprising at least one of the following components: a second compressor (14) configured to, during operation of the system, generate a desired pressure in at least one portion of the second purification unitKMU LOFT Cleanwater SE - 23 - 30A-157 398 a first heat exchanger (2) configured to, during operation of the system, enable a heat exchange between the purified condensate (16) and the process water (14); a second condenser (15) configured to, during operation of the system, condense gaseous components extracted from the second purification unit (12); one or more temperature sensors (62), each being arranged and configured to provide temperature measurements at a respective predefined position of the system; and one or more pressure sensors (64), each being arranged and configured to provide pressure measurements at a respective predefined position of the system.

12. The system of any one of claim 1 to 11, further comprising: a control unit (66) configured to control operation of the system.

13. A method (300) of treating process water using a process water treatment system (100; 200) comprising an evaporator (4a; 4b), a first purification unit (6), a first compressor (8), a condenser (10) and a second purification unit (12), the method comprising: generating (302) a desired pressure in at least one portion of the system, using the first compressor (8); at least partially evaporating (302) process water (12), using the evaporator (4a; 4b), to generate a mixture of steams (28); purifying (304) the generated mixture of steams (28), using the first purification unit (6), to obtain a purified mixture of steams (38); delivering (306) the purified mixture of steams (38) to the condenser (10), using the first compressor (8); condensing (308) the purified mixture of steams (38), using the condenser (10), to obtain a liquid condensate (32); and purifying (310) the condensate (32), using the second purification unit (12), to obtain a purified condensate (16).

14. The method of claim 13, wherein the step of purifying (304) the generated mixture of steams (28) is performed such that, when the generated mixture of steams (28) comprises at least one first substance having a boiling point higher than water, the concentration of the at least one first substance in the purified mixture of steams (38) is lower than in the generated mixture of steams (28).

15. The method of any one of claim 14, the step of purifying (304) the generated mixture of steams (28) comprises, when the generated mixture of steams (28)KMU LOFT Cleanwater SE - 24 - 30A-157 398 comprises the at least one first substance, condensing at least a part of the at least one first substance out of the generated mixture of steams (28) while maintaining a remainder of the generated mixture of steams as the purified mixture of steams (38).

16. The method of any one of claims 13 to 15, wherein the step of purifying (310) the condensate (32) is performed such that, when the condensate (32) comprises at least one second substance having a boiling point lower than water, the concentration of the at least one second substance in the purified condensate (16) is lower than in the condensate (32).

17. The method of claim 16, wherein the step of purifying (310) the condensate (32) comprises, when the generated mixture of steams (28) comprises the at least one second substance, evaporating at least a part of the at least one second substance out of the condensate (32) while maintaining a remainder of the condensate as the purified condensate (16).

18. The method of any one of claims 13 to 17, wherein the step of purifying (304) the generated mixture of steams (28) comprises putting the generated mixture of steams (28) in contact with a washing liquid (31).

19. The method of claim 18, wherein the washing liquid (31) comprises at least a part of the condensate (32) and / or at least a part of the purified condensate (16).

20. The method of any one of claims 13 to 19, wherein the step of purifying (310) the condensate (32) comprises putting the condensate (32) in contact with a washing gas (44).

21. The method of any one of claims 13 to 20, wherein the first purification unit (6) comprises a first packing material (36) and during the step of purifying (304) the generated mixture of steams (28), the generated mixture of steams (28) flows through the first packing material (36); and / or wherein the second purification unit (12) comprises a second packing material (50) and during the step of purifying (310) the condensate (32), the condensate (32) flows through the second packing material (50).

22. The method of any one of claims 13 to 21, wherein the at least one portion of the system comprises (i) a portion of the evaporator (4a; 4b) configured to houseKMU LOFT Cleanwater SE - 25 - 30A-157 398 the generated mixture of steams (28) and / or (ii) a portion of the first purification unit (6) configured to house the purified mixture of steams (38).

23. The method of any one of claims 13 to 22, further comprising at least one of the following steps: compressing the purified mixture of steams (38) before delivering (306) the purified mixture of steams (38) to the condenser (10); exchanging heat between the purified condensate (16) and the process water (14); generating a desired pressure in at least one portion of the second purification unit (12); condensing gaseous components extracted from the second purification unit (12); obtaining temperature measurements at one or more positions of the system; and obtaining pressure measurements at one or more positions of the system.

24. The system of claim 12, wherein the control unit (66) is configured to control the system to perform the method according to any one of claims 13 to 23.

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