Energy Recovery Method

Abstract

The present invention relates to a method for energy recovery, in which heat is transferred to a first heat transfer fluid, the heated first heat transfer fluid is compressed, and the compressed heat transfer fluid is used to vaporize an aqueous condensate into water vapor, which water vapor can be used for heat recovery. The present invention further relates to an apparatus for recovering water vapor and a method for compressing the heated first heat transfer fluid to a pressure p for transferring heat and vaporizing the aqueous condensate. 2 and the use of one or more means for compressing the heated first heat transfer fluid to obtain a compressed first heat transfer fluid having a

Description

[Technical field]

[0001] The present invention relates to an energy recovery method, in which heat is transferred to a first heat transfer fluid, the heated first heat transfer fluid is compressed and the compressed heat transfer fluid is used to vaporize an aqueous condensate into water vapor, which water vapor can be used for heat recovery. The present invention further relates to an installation for recovering water vapor and the use of one or more means for compressing the heated first heat transfer fluid to obtain a compressed first heat transfer fluid having a pressure p2 for transferring heat and vaporizing the aqueous condensate. [Background technology]

[0002] In connection with the effort to reduce carbon dioxide emissions, one task is to reduce the consumption of carbonaceous primary energy. This has also led to a focus on the recovery of energy in the form of heated or compressed fluids which can be used as an energy source, for example in industrial processes.

[0003] Chemical manufacturing processes, e.g., industrial processes such as processes for polymerizing polymers, often consume a lot of thermal or electrical energy, for example to heat or boil streams to the required temperatures and pressures for use or reuse, or to power the manufacturing facilities of the industrial process. On the other hand, large amounts of waste heat are generated, for example by cooling product streams, but most of these cooled streams have temperatures that are too low to be directly reused as heating media or for the production of electrical energy. As an example, well-established licensing multi-stage polymerization processes for polymerizing polyolefins are, among others, e.g. Borstar® from Borealis AG or Spheripol™ from LyondellBasell. In these processes, two or more polymerization stages are connected in series, followed by downstream processes for processing the polymerized polyolefins. In each of the polymerization stages and downstream processes, waste heat from cooling of the product streams is obtained, which is currently largely wasted.

[0004] WO 2009 / 010514 A1 and WO 2011 / 000925 A1 disclose methods for recovering heat from a cooling fluid used to cool a polymerization reaction in a loop reactor by transferring thermal energy from the cooling fluid to a working fluid in one heat exchange step, the working fluid undergoing a phase transformation, thereby returning energy in the form of heat and / or electrical power and / or thermal power to the polymerization process. However, these methods are only adapted to polymerization processes in loop reactors and require several intermediate streams for transferring thermal energy, which transfer inevitably results in energy losses and reduced efficiency. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2009 / 010514A1 Brochure [Patent Document 2] International Publication No. 2011 / 000925A1 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there is a need for a highly efficient energy recovery method that can be applied to all types of waste heat generated not only in industrial processes but also in other situations where waste heat is generated, such as power generation, engines, electronic devices or housings, to name a few.

[0007] Surprisingly, it has been found that when transferring heat from a high temperature fluid stream from any heat source to a first heat transfer fluid, thereby obtaining a heated first heat transfer fluid, this heated first heat transfer fluid can be efficiently subjected to one or more compression steps to produce a compressed first heat transfer fluid having a sufficient pressure to vaporize aqueous condensate to obtain a water vapor stream that can be used, for example, as a heating medium for energy recovery. [Means for solving the problem]

[0008] The present invention provides a method for energy recovery, comprising the steps of: a) providing a hot fluid stream; b) bringing the hot fluid stream into thermal contact with a first heat transfer fluid in a first heat exchanger, thereby transferring heat from the hot fluid stream to the first heat transfer fluid, obtaining a heated first heat transfer fluid having a temperature T1 and a pressure p1; c) subjecting the heated first heat transfer fluid to at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps to obtain a compressed first heat transfer fluid having a pressure p2; d) thermally contacting the compressed first heat transfer fluid with an aqueous condensate in a second heat exchanger, thereby transferring heat from the compressed first heat transfer fluid to the aqueous condensate and vaporizing the aqueous condensate to obtain a water vapor stream; e) using said water vapor stream for energy recovery, thereby obtaining a stream comprising an aqueous condensate; Including, The ratio of pressure p2 to pressure p1, p2 / p1, is 5 to 50; The water vapor stream used for energy recovery has a temperature T s is in the range of 120 to 200°C, preferably 130 to 170°C, more preferably 135 to 150°C, and the pressure p s is in the range of 2.0 to 15.5 barg, preferably 2.7 to 7.9 barg, more preferably 3.1 to 4.8 barg. It concerns the method.

[0009] The present invention further relates to an installation for energy recovery, comprising: a first heat exchanger for transferring heat from the hot fluid stream to a first heat transfer fluid to obtain a heated first heat transfer fluid having a temperature T1 and a pressure p1; one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means connected in series for compressing said heated first heat transfer fluid to obtain a compressed first heat transfer fluid having a pressure p2, preferably at least one, such as one or two, preferably one heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series, a second heat exchanger for transferring heat from the compressed first heat transfer fluid to an aqueous condensate to obtain a water vapor stream; means for using said water vapor stream for energy recovery, thereby obtaining a stream comprising an aqueous condensate; means for transporting the heated first heat transfer fluid from the first heat exchanger to a first upstream means for compressing the heated first heat transfer fluid; Optionally, means for transporting the compressed first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to a next downstream means for compressing the heated first heat transfer fluid in the series of means for compressing the heated first heat transfer fluid; means for transporting the compressed first heat transfer fluid having a pressure p2 from the last of the series of means for compressing the heated first heat transfer fluid to the second heat exchanger; means for transporting said aqueous condensate to said second heat exchanger; means for transporting the water vapor stream from the second heat exchanger to the means for using the water vapor stream for energy recovery; This relates to facilities including:

[0010] Still further, the present invention relates to the use of one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means for compressing a heated first heat transfer fluid, preferably at least one, such as 1 or 2, preferably one heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series, in a method or installation as described herein for compressing a heated first heat transfer fluid having a temperature T1 and pressure p1 to obtain a compressed first heat transfer fluid having pressure p2 for transferring heat and vaporizing the aqueous condensate. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 shows a schematic diagram of a prior art polyolefin polymerization stage in a fluidized bed gas phase reactor in which heat is transferred and rejected from a circulating gas stream in one heat exchange step. [Diagram 2] Figure 2 shows a schematic diagram of a polyolefin polymerization stage in a fluidized bed gas phase reactor where heat is transferred from a circulating gas stream in two successive heat exchange steps. The heated cooling fluid from the first heat exchange step can be used for energy recovery, while the residual heat transferred in the second heat exchange step is wasted. [Diagram 3]FIG. 3 shows a schematic diagram of the heat recovery method of the present invention applied as an example in a fluidized bed gas phase reactor stage of an olefin polymerization process, where heat is transferred from a circulating gas stream to a first heat transfer fluid in a first heat exchange step (GPR precooler) and the heated cooling fluid is fed to a compressor heat pump where its thermal energy is used to generate a low pressure steam stream. [Figure 4] Figure 4 shows a proposed example of the embodiment of Figure 3 using n-pentane as the first heat transfer fluid, which is discussed further below in the Examples section. [Diagram 5] 5 shows a proposed example of a further embodiment of the heat recovery process of the present invention in which the low pressure steam stream is subjected to a steam drum or attemperator to produce a steam stream having a temperature and pressure in the range required for direct use in a polymerization process, which proposed example is discussed further below in the Examples section. [Figure 6] 6 shows a proposed example of a further embodiment of the heat recovery method of the present invention in which the low pressure steam stream is subjected to a further compression step in a compressor heat pump to produce a steam stream having a temperature and pressure in the range required for direct use in a polymerization process, which proposed example is discussed further below in the Examples section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] method In a first aspect, the present invention provides a method for energy recovery comprising the steps of: a) providing a hot fluid stream; b) bringing said hot fluid stream into thermal contact with a first heat transfer fluid in a first heat exchanger, thereby transferring heat from the hot fluid stream to the first heat transfer fluid, obtaining a heated first heat transfer fluid having a temperature T1 and a pressure p1; c) subjecting the heated first heat transfer fluid to at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps to obtain a compressed first heat transfer fluid having a pressure p2; d) thermally contacting the compressed first heat transfer fluid with the aqueous condensate in a second heat exchanger, thereby transferring heat from the compressed first heat transfer fluid to the aqueous condensate and vaporizing the aqueous condensate to obtain a water vapor stream; e) using the water vapor stream for energy recovery, thereby obtaining a stream comprising an aqueous condensate; Including, The ratio of pressure p2 to pressure p1, p2 / p1, is 5 to 50; The steam stream used for energy recovery has a temperature of T s is in the range of 120 to 200°C, preferably 130 to 170°C, more preferably 135 to 150°C, and the pressure p s is in the range of 2.0 to 15.5 barg, preferably 2.7 to 7.9 barg, more preferably 3.1 to 4.8 barg. It concerns the method.

[0013] The hot fluid stream has a temperature T f has. The method of the present invention can therefore also be used to recover energy from fluid streams having moderate temperatures. Therefore, the term "high temperature" in this context refers to a temperature T of the high temperature fluid stream such that heat can be exchanged from the high temperature fluid stream to the first heat transfer fluid. f is higher than the temperature T0 of the first heat transfer fluid before it enters the first heat exchanger.

[0014] The high temperature fluid stream can be provided from any type of fluid stream at an elevated temperature. The source of the high temperature fluid stream can be an industrial process or any type of other situation where waste heat is produced in the form of an elevated temperature fluid stream, such as power generation, engines, electronic equipment or housings, etc.

[0015] In one preferred embodiment, the high temperature fluid stream is provided from an industrial process, more preferably from a chemical manufacturing process. The chemical manufacturing process can be any process for producing chemical products in which heat can be provided from a high temperature fluid stream. In one particular embodiment, the chemical manufacturing process is a polymerization process. The polymerization process is preferably a process for polymerizing an α-olefin polymer. The polymerization process is preferably a low pressure process for polymerizing an α-olefin polymer in the presence of a polymerization catalyst.

[0016] The polymerization catalyst can be any suitable catalyst for polymerizing α-olefin polymers, such as a supported or unsupported Ziegler-Natta catalyst or a metallocene catalyst.

[0017] The α-olefin polymer can be a homopolymer or copolymer of ethylene and / or an α-olefin monomer having from 3 to 12 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene or 1-octene. Preference is given to ethylene homopolymers or copolymers of ethylene and one or more α-olefin comonomers having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-hexene and / or 1-octene, as well as propylene homopolymers or copolymers of propylene and ethylene or one or more α-olefin comonomers having 4 to 12 carbon atoms, such as ethylene, 1-butene, 1-hexene and / or 1-octene.

[0018] The polymerization process may be a single stage polymerization process or a multi-stage polymerization process. In a one-stage polymerization process, the polymer polymerization is carried out in one polymerization reactor which may be selected from slurry phase reactors, such as loop reactors, and gas phase reactors, such as fluidized bed gas phase reactors. The polymerization process is preferably a multi-stage polymerization process in which two or more reactors, preferably from 2 to 6 reactors, such as 2, 3, 4, 5 or 6 reactors, are connected in series. The two or more reactors are usually selected from slurry phase reactors, such as loop reactors, and gas phase reactors, such as fluidized bed gas phase reactors. Downstream of the reactor stage(s) of the polymerization process, the polymer is further processed. In this downstream processing stage, the polymer is preferably separated from unreacted monomers and other components of the production stream. Furthermore, the polymer is preferably compounded in an extruder with applicable additives, as known in the art.

[0019] Typical multi-stage polymerization processes to which the method of the present invention can be applied are, inter alia, for example Borstar® PE and Borstar® PP from Borealis AG or Spheripol® from LyondellBasell.

[0020] The hot fluid stream may be provided from any process stage of a chemical manufacturing process, for example from one or more or all of the manufacturing stages where a chemical product or any precursor or intermediate is produced, and / or from a processing stage downstream from the manufacturing stage(s), for example a purification stage or a blending stage.

[0021] It is especially preferred that the hot fluid stream is not a cooling stream from a heat exchange process. Instead, the hot fluid stream is preferably one which is obtained directly without indirect heat exchange or energy transfer.

[0022] The hot fluid stream may be a slurry stream, a liquid stream or a gaseous stream. When being a slurry stream or liquid stream, the hot fluid stream is preferably at a temperature T in the range of 20 to 150° C., more preferably 25 to 130° C., and most preferably 30 to 110° C. f has. When being a gaseous stream, the hot fluid stream is preferably at a temperature T in the range of 50 to 150° C., preferably 55 to 130° C., most preferably 65 to 110° C. f and has a pressure in the range of 5 to 50 bar, preferably 8 to 40 bar, and most preferably 10 to 35 bar.

[0023] In a chemical manufacturing process embodiment, the hot fluid stream is preferably a hot product stream. In the above polymerization process embodiments, the hot product stream is preferably selected from a hot polymer slurry stream of a slurry phase polymerization stage, a hot circulating gas stream from a gas phase polymerization stage or a hot polymer stream from a processing stage downstream from the polymerization stage(s), for example from an extrusion stage. The hot fluid stream can also be the primary water circuit of an extruder in a processing stage downstream from the polymerization stage, for example from an extrusion stage.

[0024] The hot fluid stream provided from the polymerization process preferably comprises monomer, optionally comonomer (both as defined above), and optionally a chain transfer agent, such as hydrogen. The hot fluid stream preferably comprises a polymer if it is a hot polymer slurry stream from a slurry phase polymerization stage or a hot polymer stream from a processing stage downstream from the polymerization stage.

[0025] The hot fluid stream is preferably transported directly to the first heat exchanger, where "directly" means that the hot fluid stream does not undergo any further processing that would manipulate the temperature of the hot fluid stream.

[0026] In the first heat exchanger, the hot fluid stream is brought into thermal contact with a first heat transfer fluid such that heat is transferred from the hot fluid stream to the first heat transfer fluid, resulting in a heated first heat transfer fluid having a temperature T1.

[0027] The first heat transfer fluid is preferably selected from a refrigerant. The refrigerant is preferably selected from hydrocarbons such as propane, isobutene, n-butane, cyclopropane, ethane, n-pentane, isopentane, cyclopentane or mixtures thereof, halogenated hydrocarbons such as hydrochlorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons or mixtures thereof, such as methyl chloride, dichloromethane, monofluorodichloromethane, monochlorodifluoromethane, trichlorotrifluoroethane, 1,2-dichlorotetrafluoroethane, 2,2-dichloro-1,1,1-trifluoroethane, 1,1-difluoromethane or mixtures thereof, natural refrigerants such as ammonia, carbon dioxide or sulfur dioxide, or nanofluids. Particularly preferred refrigerants are hydrocarbons such as propane, isobutene, n-butane, cyclopropane, ethane, n-pentane, isopentane, cyclopentane or mixtures thereof, preferably isobutene, n-butane, n-pentane, isopentane, cyclopentane or mixtures thereof, more preferably n-pentane, isopentane or cyclopentane.

[0028] The first heat transfer fluid is preferably only used when used in a closed energy recovery cycle in which the first heat transfer fluid is used as a heating / cooling medium.

[0029] Before being subjected to the heat transfer step b), the first heat transfer fluid is preferably liquid. Before being subjected to the heat transfer step b), the first heat transfer fluid preferably has a temperature T0 in the range of 15-75°C, more preferably 20-72°C, most preferably 25-70°C.

[0030] After heat transfer, the cooled fluid stream has a temperature T f1 The T of the cooled fluid stream f1 is the temperature of the hot fluid stream, T f The T of the cooled fluid stream is f1 The heating temperature may be in the range of 15 to 145°C, more preferably 20 to 125°C, and even more preferably 25 to 98°C.

[0031] In an embodiment of a chemical manufacturing process, it has been found that a more efficient heat transfer from the hot fluid stream to a first heat transfer fluid can be achieved if the hot fluid stream is subjected to two subsequent heat exchange steps in two heat exchangers connected in series. Thereby, the heat transfer step b) is preferably carried out in the upstream heat exchanger of two heat exchangers connected in series. Residual heat from the cooled fluid stream removed from the upstream heat exchanger can then be transferred to a further heat transfer fluid in the downstream one of the two heat exchangers connected in series. Usually the temperature of the heated further heat transfer fluid is too low to allow it to be further used in energy recovery, therefore it is removed in a storage means, for example a cooling tower. The further heat transfer fluid may be a refrigerant as described above for the first heat transfer fluid or water.

[0032] The heated first heat transfer fluid is used for energy recovery.

[0033] After the heat transfer in method step b), the heated first heat transfer fluid preferably has a T1 in the range of 30-80°C, preferably 40-75°C, more preferably 50-70°C.

[0034] The pressure p1 of the heated first heat transfer fluid after heat transfer in method step b) is preferably in the range of 0.5 to 2.0 barg, preferably 0.7 to 1.8 barg, more preferably 1.0 to 1.5 barg.

[0035] In the heat transfer step b) the first heat transfer fluid is preferably vaporized to obtain a vaporized heated first heat transfer fluid having a temperature T1 and a pressure p1. A liquid to gas phase change is preferred since it results in a more efficient transfer of energy via enthalpy of vaporization from the hot fluid stream to the first heat transfer fluid.

[0036] For example, for direct use as a heat source or to generate a water vapor stream, the temperature T1 and pressure p1 of the heated first heat transfer fluid are usually too low to allow efficient energy recovery. Thus, in the method of the present invention, the pressure of the heated first heat transfer fluid is increased to a pressure p2.

[0037] Thus, in a subsequent method step c), the heated first heat transfer fluid is subjected to at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps to obtain a compressed first heat transfer fluid having a pressure p2.

[0038] For the compression step, preferably at least one, e.g. one or two, preferably one heat pump compressor is used. Each heat pump compressor preferably comprises at least one, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series. The at least one heat pump compressor is preferably part of a heat pump as known in the art.

[0039] If multiple compression stages are used, the compression stages are preferably arranged in series, preferably by using one or more heat pump compressors, with at least one, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages arranged in series. In the serial configuration, the heated first heat transfer fluid is first subjected to a first compression step, preferably in a first (initial) upstream compression stage of the heat pump compressor, whereby the pressure of the heated first heat transfer fluid is increased by a first increment in the first step. The heated first heat transfer fluid compressed in the first step is then subjected to a next downstream compression step, preferably in a second compression stage of the heat pump compressor located downstream from the first upstream compression stage of the heat pump exchanger, whereby the pressure of the heated first heat transfer fluid is increased by a second increment in the second step. This is optionally repeated until a compressed first heat transfer fluid with pressure p2 is obtained in the last downstream heat exchange step, preferably in the last downstream compression stage of the heat pump compressor.

[0040] During at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps as described above, the temperature of the heated first heat transfer fluid is preferably raised to a temperature T2. When multiple compression steps are used, the temperature of the heated first heat transfer fluid is increased in increments during each compression step, typically in parallel with the increments of pressure increase as discussed above.

[0041] The increments of temperature and pressure increase in the subsequent compression steps typically depend on the volumetric stream of heated first heat transfer fluid and the size and power of each heat pump compressor. p at each compression step out / p in It is preferred that the increments of pressure increase, determined as the ratio of, are independently in the range of 1.3 to 3, preferably 1.5 to 2.5. Preferably, the increment of temperature rise in each compression step is independently in the range of 25-250K, preferably 50-200K.

[0042] In some embodiments, the temperature increase in the compression process can result in a temperature of the compressed first heat transfer fluid of about 300° C. Temperatures above 300° C. are undesirable due to the fragility or potential failure of the affected pipes, armature and fittings materials. It is therefore preferred that the temperature of the compressed first heat transfer fluid after one or more compression steps, preferably after each compression step, is reduced so that the temperature of the compressed first heat transfer fluid does not exceed 300°C.

[0043] The temperature of the compressed first heat transfer fluid may be reduced after one or more heating and compression steps, preferably after each heating and compression step, by combining the compressed heated first heat transfer fluid stream with a higher pressure liquid first heat transfer fluid. The compressed first heat transfer fluid is preferably combined with a higher pressure liquid first heat transfer fluid in an attemperator.

[0044] The amount of compression steps is preferably proposed by considering the expected pressure increase increment of each compression step to obtain a compressed first heat transfer fluid having a pressure p2.

[0045] The pressure increase in at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 to 3 compression steps is such that the ratio of pressure p2 to pressure p1, p2 / p1, is 5 to 50, preferably 10 to 40, most preferably 15 to 30.

[0046] The pressure p2 is preferably in the range of 10.0 to 20.0 barg, more preferably 12.0 to 18.0 barg, and even more preferably 14.0 to 16.0 barg.

[0047] The compressed first heat transfer fluid having a pressure p2 preferably has a temperature T2. The temperature T2 is preferably 50K to 250K higher, more preferably 65K to 150K higher, and most preferably 75K to 125K higher than the temperature T1.

[0048] The compressed first heat transfer fluid having a pressure p2 is used for energy recovery. Since the first heat transfer fluid is typically a refrigerant as mentioned above, the compressed first heat transfer fluid having pressure p2 is typically not suitable for direct use in energy recovery. Therefore, the method of the present invention suggests a second heat transfer step d) in which the compressed first heat transfer fluid is brought into thermal contact with the aqueous condensate in a second heat exchanger, thereby transferring heat from the compressed first heat transfer fluid to the aqueous condensate and vaporizing the aqueous condensate to obtain a water vapor stream.

[0049] In a preferred embodiment, the compressed first heat transfer fluid is in gaseous form as described above. In the second heat exchanger, the compressed first heat transfer fluid can be liquefied. By liquefying the compressed first heat transfer fluid in heat exchange step d) in the second heat exchanger, a more efficient heat transfer from the compressed first heat transfer fluid to the aqueous condensate is obtained. The first heat transfer fluid removed from the second heat exchanger may also be in gaseous form.

[0050] Preferably, the first heat transfer fluid removed from the second heat exchanger in step d) is redirected to the first heat exchanger and used as the first heat transfer fluid in step b).

[0051] Thereby, the first heat transfer fluid withdrawn from the second heat exchanger in step d) can be used as a heating medium in further optional heat transfer steps, such as an optional heat transfer step, before or during the compression step c). Thereby, the gaseous first heat transfer fluid removed from the second heat exchanger can be liquefied in a further optional heat transfer step.

[0052] The first heat transfer fluid removed from the second heat exchanger in step d) may be used as the higher pressure liquid first heat transfer fluid in the attemperator, as described above.

[0053] In one embodiment, sufficient energy is transferred from the compressed first heat transfer fluid to the steam stream withdrawn from the second heat exchanger in step d) such that the steam stream withdrawn from the second heat exchanger has a temperature T in the range of 120 to 200° C., preferably 130 to 170° C., more preferably 135 to 150° C. s and pressure p s The pressure is in the range of 2.0 to 15.5 barg, preferably 2.7 to 7.9 barg, more preferably 3.1 to 4.8 barg. This water vapor stream can be used directly for energy recovery.

[0054] In another embodiment, the stream removed from the second heat exchanger is T s and / or p s The steam has a lower temperature and / or pressure than the steam produced by the steam extraction process, so that this steam stream is poorly usable for energy recovery. In the above embodiment, the water vapor stream removed from the second heat exchanger is preferably compressed in at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps, to a temperature T s and pressure p s A compressed water vapor stream having For the compression step, preferably at least one, e.g. one or two, preferably one heat pump compressor is used. Each heat pump compressor preferably comprises at least one, preferably 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression stages connected in series. The at least one heat pump compressor is preferably part of a heat pump as known in the art. The water vapor stream is heated to temperature T s and pressure p sIt is especially preferred that the compression step for compressing to is carried out in at least one, e.g. 1 or 2, preferably 1, compression stage of a heat pump compressor which is used for at least one, e.g. 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps of method step c).

[0055] temperature T s and pressure p s The water vapor stream having

[0056] One suitable means of energy recovery is to use a water vapor stream as a heating medium. In a manufacturing facility, the steam stream can be used at any stage of the industrial process or even in the heating system of the manufacturing facility, for example as a heating medium to heat the product stream, any other stream, some of the components of the manufacturing site. Preferably, in a polymerization process as discussed above, the compressed steam stream can be used to replace steam in a reboiler in a step for recovering monomer, comonomer and other reactants of the polymerization process, or to heat a flash tank in a gas phase polymerization stage. Suitable methods for storing thermal energy are, for example, methods using reverse condensation reactions, such as chemical heat pumps, which are commercialized by Qpinch and are described, for example, inter alia, in WO 2014 / 016405 A1. A suitable method for generating electricity has been commercialized by Climeon and is described, for example, inter alia, in EP 2 689 111 A1. For example, excess compressed steam stream not used for energy recovery within an industrial process may also be used as a heating medium or other form of energy recovery outside the industrial process.

[0057] temperature T s and pressure p sBy using the water vapor stream having the above formula for energy recovery, the temperature and pressure of the heated and compressed water vapor stream is reduced to such an extent that the water vapor stream at least partially condenses to provide a stream comprising an aqueous condensate.

[0058] The stream comprising the aqueous condensate, after being used for energy recovery, is preferably at least partially liquid, for example at least 60% by weight liquid, preferably at least 75% by weight liquid, most preferably at least 90% by weight liquid. Thereby, the non-liquid portion of the aqueous condensate is gaseous, i.e. up to 40% by weight, preferably up to 25% by weight, most preferably up to 10% by weight. In some embodiments, the aqueous condensate is 100% by weight liquid, depending on the temperature and pressure conditions after energy recovery.

[0059] Temperature T used for heat recovery s and pressure p s Preferably, the stream comprising the aqueous condensate obtained from the water vapor stream having the formula: is subjected to a steam separation step to obtain a second water vapor stream and an aqueous condensate.

[0060] The aqueous condensate can be used in a second heat exchanger to transfer heat from the compressed first heat transfer fluid to the aqueous condensate and vaporize at least a portion of the aqueous condensate to obtain a water vapor stream. The second water vapor stream is preferably combined with the water vapor stream during the compression step to provide a water vapor stream at temperature T s and pressure p s It is possible to obtain a water vapor stream having

[0061] The aqueous condensate is preferably liquid water, such as tap water. The aqueous condensate is preferably only used when the aqueous condensate is used as a heating and cooling medium as well as in a closed energy recovery cycle where the aqueous condensate is used to generate electrical energy. The aqueous condensate is preferably not separated from or introduced into the product stream of the industrial production process.

[0062] manufacturing equipment In a further aspect, the present invention provides an installation for energy recovery, comprising: a first heat exchanger for transferring heat from the hot fluid stream to a first heat transfer fluid to obtain a heated first heat transfer fluid having a temperature T1 and a pressure p1; one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means for compressing the heated first heat transfer fluid in series to obtain a compressed first heat transfer fluid having a pressure p2, preferably at least one, e.g. one or two, preferably one heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages in series, a second heat exchanger for transferring heat from the compressed first heat transfer fluid to the aqueous condensate to obtain a water vapor stream; means for using the water vapor stream for energy recovery, thereby obtaining a stream comprising an aqueous condensate; means for transporting the heated first heat transfer fluid from the first heat exchanger to a first upstream means for compressing the heated first heat transfer fluid; Optionally, means for transporting the compressed first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to a next downstream means for compressing the heated first heat transfer fluid in the series of means for compressing the heated first heat transfer fluid; means for transporting the compressed first heat transfer fluid having a pressure p2 from the last of the series of means for compressing the heated first heat transfer fluid to a second heat exchanger; means for transporting the aqueous condensate to the second heat exchanger; means for transporting the water vapor stream from the second heat exchanger to means for using the water vapor stream for energy recovery; This relates to facilities including:

[0063] The facility can be any type of facility where high temperature fluid streams are generated and can be used for energy recovery, non-limiting examples are industrial manufacturing sites such as chemical manufacturing sites, especially polymerization manufacturing sites, power generation facilities, facilities containing engines or electronic equipment or housings.

[0064] The installation is preferably adapted to all aspects and embodiments of the inventive method for recovering water vapor as described above or below.

[0065] In the case of a chemical manufacturing site, the facility preferably further comprises means for producing chemicals, such as one or more reactors. Furthermore, the facility preferably includes means for post-production processing of chemical products, such as means for purifying chemical products and / or means for blending chemical products, or other means required for processing and finishing chemical products. Still further, the facility preferably includes means for transporting educts, products and / or other components used in the chemical manufacturing process to the means for producing a chemical product, and from the means for producing a chemical product to means for post-production processing of the chemical product, and to each of the means for process steps therebetween.

[0066] In a polymerization production site, the means for producing a chemical product preferably includes a polymerization reactor. The polymerization reactor may be one polymerization reactor or multiple polymerization reactors connected in series. One polymerization reactor may be selected from slurry phase reactors, such as loop reactors, and gas phase reactors, such as fluidized bed gas phase reactors. The multiple polymerization reactors are preferably two or more polymerization reactors, and preferably 2 to 6 polymerization reactors, for example, 2, 3, 4, 5 or 6 polymerization reactors, connected in series. The multiple polymerization reactors are usually selected from slurry phase reactors, such as loop reactors, and gas phase reactors, such as fluidized bed gas phase reactors.

[0067] The means for treating the polymer powder downstream from at least one polymerization reactor preferably includes means for separating the polymer from unreacted monomer, comonomer and other components of the product stream. Furthermore, the means for processing the polymer powder downstream from the at least one polymerization reactor preferably comprise means for compounding the polymer, such as an extruder.

[0068] The system includes at least a first heat exchanger. The facility may include a plurality of first heat exchangers, for example at least one set of at least two first heat exchangers connected in series. The number of sets of at least two first heat exchangers connected in series may be 1-10, for example 1, 2, 3, 4, 5 or 6. The set of at least two first heat exchangers connected in series can include two or more, for example 2 to 6, preferably 2, 3 or 4, most preferably 2 heat exchangers connected in series.

[0069] In a polymerization production site, the number of sets of at least two first heat exchangers connected in series usually depends on the number of polymerization reactors and the number of means for treating polymer powder downstream from at least one polymerization reactor. A set of at least two first heat exchangers connected in series can be connected to each polymerization reactor of the production facility and / or to a means for processing polymer powder downstream from at least one polymerization reactor, preferably a means for compounding polymers, such as an extruder.

[0070] The installation comprises one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means for compressing the heated first heat transfer fluid to obtain a compressed first heat transfer fluid having pressure p2. The one or more means for compressing the heated first heat transfer fluid are preferably connected in series. The one or more means for compressing the heated first heat transfer fluid are preferably one or more, such as one or two, preferably one, heat pump compressors. Each heat pump compressor preferably comprises 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series. The one or more, such as one or two, preferably one, heat pump compressors are preferably part of one or more heat pumps as known in the art.

[0071] The facility further includes a second heat exchanger for transferring heat from the compressed first heat transfer fluid to the aqueous condensate to obtain a water vapor stream.

[0072] Still further, the facility includes means for using the water vapor stream for energy recovery. The means for using the water vapor stream for energy recovery may be means for using the water vapor stream as a heating medium. In an industrial manufacturing site, the means for using a steam stream as a heating medium may be at any stage of the industrial production process or even in the heating system of the manufacturing site, for example means for heating the product stream, any other stream, part of the components of the manufacturing site. Such means may be a heat exchanger, a reboiler or a heating system. The means for energy recovery may be a means for temporary storage of the high temperature and / or pressure stream prior to use. The means for using the water vapor stream for energy recovery may also be means for thermal energy storage, for example for applying the method using a reverse condensation reaction, such as a chemical heat pump, as commercialized by Qpinch and described, inter alia, in WO 2014 / 016405 A1.

[0073] The means for transporting the heated first heat transfer fluid from the first heat exchanger to the first upstream means for compressing the heated first heat transfer fluid is preferably a pipe for connecting the first heat exchanger to the first means for compressing the heated first heat transfer fluid. In one embodiment, the first heat exchanger is directly connected to the first means for compressing the heated first heat transfer fluid by means for transporting the heated first heat transfer fluid from the first heat exchanger to the first means for compressing the heated first heat transfer fluid. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the heated first heat transfer fluid. In another embodiment, the first heat exchanger is not directly connected to the first means for compressing the heated first heat transfer fluid by means for transporting the heated first heat transfer fluid from the first heat exchanger to the first means for compressing the heated first heat transfer fluid. In this embodiment, the means for transporting the heated first heat transfer fluid from the first heat exchanger to the first upstream means for compressing the heated first heat transfer fluid passes through a means for manipulating the temperature or pressure of the heated first heat transfer fluid, for example a further heat exchanger. The heat exchanger may be used to preheat the heated first heat transfer fluid prior to introduction to the first means for compressing the heated first heat transfer fluid.

[0074] When multiple means for compressing the heated first heat transfer fluid are connected in series, the installation includes means for transporting the heated first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to the next downstream means for compressing the heated first heat transfer fluid in the series of means for compressing the heated first heat transfer fluid. Preferably, the means for transporting the heated first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to a next downstream means for compressing the heated first heat transfer fluid is preferably a pipe for connecting one upstream means for compressing the heated first heat transfer fluid to a next downstream means for compressing the heated first heat transfer fluid. Preferably, in the series of means for compressing the heated first heat transfer fluid, each upstream means for compressing the heated first heat transfer fluid is connected to the next downstream means for compressing the heated first heat transfer fluid via means for transporting the heated first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to the next downstream means for compressing the heated first heat transfer fluid. The upstream and next downstream means for compressing the heated first heat transfer fluid may be directly connected via a means for transporting the heated first heat transfer fluid from one upstream means for compressing the heated first heat transfer fluid to the next downstream means for compressing the heated first heat transfer fluid. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the heated first heat transfer fluid.

[0075] In one embodiment, the installation further comprises at least one means for compressing the heated first heat transfer fluid, preferably downstream of each means, a means for cooling the heated first heat transfer fluid. Downstream of at least one means, preferably each means, for compressing the heated first heat transfer fluid, said means for cooling the heated first heat transfer fluid are preferably means for combining the heated first heat transfer fluid with a liquid first heat transfer fluid at a higher pressure. Downstream of at least one, and preferably each, means for compressing the heated first heat transfer fluid is a suitable means for cooling the heated first heat transfer fluid, most preferably an attemperator as known in the art.

[0076] The installation also includes a means for transporting the compressed first heat transfer fluid having a pressure p2 from the last in the series of means for compressing the heated first heat transfer fluid to the second heat exchanger. The means for transporting the compressed first heat transfer fluid having pressure p2 from the last of the series of means for compressing the heated first heat transfer fluid to the second heat exchanger is preferably a pipe for connecting the last of the series of means for compressing the heated first heat transfer fluid to the second heat exchanger. The last means in the series of means for compressing the heated first heat transfer fluid is preferably directly connected to the second heat exchanger by means for transporting the compressed first heat transfer fluid having pressure p2 from the last means in the series of means for compressing the heated first heat transfer fluid to the second heat exchanger. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the compressed first heat transfer fluid.

[0077] The system also includes a means for transporting the aqueous condensate to a second heat exchanger. The means for transporting the aqueous condensate to the second heat exchanger is preferably a pipe for connecting a storage device for storing the aqueous condensate to the second heat exchanger. The means for transporting the aqueous condensate to the second heat exchanger is preferably a means for transporting the aqueous condensate from the means for using the water vapor stream to the second heat exchanger.

[0078] Still further, the facility includes means for transporting the water vapor stream from the second heat exchanger to a means for using the water vapor stream for energy recovery. The means for transporting the water vapor stream from the second heat exchanger to the means for using the water vapor stream for energy recovery is preferably a pipe for connecting the second heat exchanger to the means for using the water vapor stream for energy recovery.

[0079] In one embodiment, the second heat exchanger is directly connected to the means for using the water vapor stream for energy recovery by means for transporting the water vapor stream from the second heat exchanger to the means for using the water vapor stream for energy recovery. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the water vapor stream.

[0080] In another embodiment, the second heat exchanger is not directly connected to the means for using the water vapor stream for energy recovery by means for transporting the water vapor stream from the second heat exchanger to the means for using the water vapor stream for energy recovery. In the above embodiment, the facility preferably comprises: one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, steam streams connected in series to be compressed to a temperature T s and pressure p s means for obtaining a water vapor stream having the formula: means for transporting the water vapor stream from the second heat exchanger to a first upstream means for compressing the water vapor stream; optionally means for transporting the water vapor stream from an upstream means for compressing the water vapor stream to a next downstream means for compressing the water vapor stream in a series of means for compressing the water vapor stream; ·Temperature T s and pressure p s means for transporting the water vapor stream having said first compression means from a last in the series of means for compressing said water vapor stream to a means for using said water vapor stream for energy recovery; Further includes:

[0081] In this regard, the present invention relates to one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, serially connected means for compressing a heated first heat transfer fluid having a temperature T1 and a pressure p1 to obtain a compressed first heat transfer fluid having a pressure p2, and one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, serially connected means for compressing a water vapor stream to a temperature T s and pressure p s The means for obtaining a water vapor stream having is preferably a compression stage of the same heat pump compressor.

[0082] The means for transporting the water vapor stream from the second heat exchanger to the first upstream means for compressing the water vapor stream is preferably a pipe for connecting the second heat exchanger to the first upstream means for compressing the water vapor stream by the means for transporting the water vapor stream from the second heat exchanger to the first upstream means for compressing the water vapor stream. The second heat exchanger is preferably directly connected to the first upstream means for compressing the water vapor stream by the means for transporting the water vapor stream from the second heat exchanger to the first upstream means for compressing the water vapor stream. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the water vapor stream.

[0083] When multiple means for compressing a water vapor stream are connected in series, the installation includes means for transporting the water vapor stream from one upstream means for compressing the water vapor stream to the next downstream means for compressing the water vapor stream in the series of means for compressing the water vapor stream. Preferably, the means for transporting the water vapor stream from one upstream means for compressing the water vapor stream to a next downstream means for compressing the water vapor stream is preferably a pipe for connecting one upstream means for compressing the water vapor stream to a next downstream means for compressing the water vapor stream. Preferably, in the series of means for compressing a water vapor stream, each upstream means for compressing a water vapor stream is connected to the next downstream means for compressing a water vapor stream via means for transporting the water vapor stream from the one upstream means for compressing a water vapor stream to the next downstream means for compressing a water vapor stream. The upstream and next downstream means for compressing the water vapor stream may be directly connected via a means for transporting the water vapor stream from one upstream means for compressing the water vapor stream to the next downstream means for compressing the water vapor stream. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the water vapor stream.

[0084] temperature T s and pressure p s The means for transporting the water vapor stream having a temperature T from the last of the series of means for compressing the water vapor stream to the means for using the water vapor stream for energy recovery is preferably a pipe for connecting the last of the series of means for compressing the water vapor stream to the means for using the water vapor stream for energy recovery. The last of the series of means for compressing the water vapor stream preferably has a temperature T s and pressure p sto the means for using the water vapor stream for energy recovery by a means for transporting the water vapor stream having a temperature of from the last in the series of means for compressing the water vapor stream to the means for using the water vapor stream for energy recovery. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the water vapor stream.

[0085] Preferably, the installation further comprises means for transporting the first heat transfer fluid from the second heat exchanger to the first heat exchanger, said means for transporting the first heat transfer fluid from the second heat exchanger to the first heat exchanger being preferably a pipe for connecting the second heat exchanger to the first heat exchanger. In one embodiment, the second heat exchanger is directly connected to the first heat exchanger by means for transporting the first heat transfer fluid from the second heat exchanger to the first heat exchanger, "directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the first heat transfer fluid. In another embodiment, the second heat exchanger is not directly connected to the first heat exchanger by a means for transporting the first heat transfer fluid from the second heat exchanger to the first heat exchanger. In the above embodiments, the means for transporting the first heat transfer fluid from the second heat exchanger to the first heat exchanger passes through a means for manipulating the temperature or pressure of the first heat transfer fluid, such as a heat exchanger or attemperator as discussed above.

[0086] The equipment in question: means for separating a second water vapor stream and an aqueous condensate from a stream including the aqueous condensate obtained from the means for using the water vapor stream; means for transporting the stream comprising the aqueous condensate from the means for using the water vapor stream to means for separating the second water vapor stream and the aqueous condensate from the stream comprising the aqueous condensate; one or more, preferably 1 to 5, more preferably 2 to 4, and most preferably 2 or 3, water vapor streams connected in series with the means for separating the second water vapor stream and the aqueous condensate, s and pressure p s a means for transferring the water vapor to the means for obtaining a water vapor stream having the ... It is preferred that the composition further comprises:

[0087] The means for separating the second steam stream and the aqueous condensate from the stream containing aqueous condensate obtained from the means for using the steam stream may be any means suitable for separating a liquid stream from a gaseous stream, for example a vapor-liquid separator as known in the art.

[0088] The means for transporting the stream comprising aqueous condensate from the means for using the water vapor stream to the means for separating a second water vapor stream and an aqueous condensate from the stream comprising aqueous condensate is preferably a pipe for connecting, preferably directly connecting, the means for using the water vapor stream for energy recovery to the means for separating a second water vapor stream and an aqueous condensate from the stream comprising aqueous condensate, "directly connecting" in this context meaning that the means is not connected to any further means for manipulating the temperature or pressure of the stream comprising aqueous condensate.

[0089] The second water vapor stream is passed through one or more, preferably 1 to 5, more preferably 2 to 4, and most preferably 2 or 3, steam compressors connected in series to compress the second water vapor stream to a temperature T s and pressure p s The means for compressing the water vapor stream to the means for obtaining a water vapor stream having a temperature Ts and pressure p s Preferably, the pipe is for connecting, preferably directly connecting, to a means for obtaining a water vapor stream having a second water vapor stream having a temperature of from about 1000 to about 10000 s. "Directly connecting" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the second water vapor stream.

[0090] The production facility preferably further comprises means for transporting a stream comprising the aqueous condensate from the means for using the water vapor stream to the second heat exchanger. The means for transporting the stream comprising the aqueous condensate from the means for using the water vapor stream to the second heat exchanger is preferably a means for transporting the aqueous condensate to the second heat exchanger. The means for transporting the stream comprising the aqueous condensate from the means for using the water vapor stream to the second heat exchanger is preferably a pipe for connecting the means for using the water vapor stream to the second heat exchanger.

[0091] In one embodiment, the second heat exchanger is directly connected to the means for using the water vapor stream by means for transporting the stream comprising aqueous condensate from the means for using the water vapor stream to the second heat exchanger. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the stream comprising aqueous condensate. In another embodiment, the second heat exchanger is connected, preferably directly connected, to the means for separating the second steam stream and the aqueous condensate from the stream comprising aqueous condensate by means for transporting the stream comprising aqueous condensate from the means for separating the second steam stream and the aqueous condensate from the stream comprising aqueous condensate to the second heat exchanger. "Directly connected" in this context means that the means is not connected to any further means for manipulating the temperature or pressure of the stream comprising aqueous condensate.

[0092] use In a further aspect the invention relates to the use of one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means for compressing a heated first heat transfer fluid, preferably at least one, such as 1 or 2, preferably one heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series, in a method or installation as described herein for compressing a heated first heat transfer fluid having a temperature T1 and pressure p1 to obtain a compressed first heat transfer fluid having pressure p2 for transferring heat and vaporizing the aqueous condensate.

[0093] Preferably, all aspects and embodiments of the one or more means, methods or production installations for compressing a heated first heat transfer fluid according to the invention described above or below apply for the use of the present invention.

[0094] Detailed Description of the Drawings and Preferred Embodiments FIG. 1 shows a schematic diagram of a prior art polyolefin polymerization stage in a fluidized bed gas phase reactor. The hot circulating gas stream, containing unreacted monomer and optionally comonomer and chain transfer agent, is removed from the top of the fluidized gas bed reactor and recycled by a pump back to the bottom of the fluidized bed reactor. This transports the hot circulating gas stream through a single heat exchanger where the heat of the hot circulating gas stream is transferred to cooling water. Because the temperature and pressure of the heated cooling water are too low for energy storage, the heated cooling water is directed to a cooling tower.

[0095] Figure 2 shows a schematic diagram of a polyolefin polymerization stage in a fluidized bed gas phase reactor, in which heat is transferred from a circulating gas stream in two successive heat exchange steps. The heated cooling water from the first heat exchange step in the upstream heat exchanger has a temperature and pressure within the range that can be used in the inventive method for energy recovery. The temperature and pressure of the heated cooling water from the second heat exchange step in the downstream heat exchanger are too low for energy storage, so the heated cooling water is led to a cooling tower.

[0096] FIG. 3 shows a schematic diagram of an embodiment of the method of the present invention in an example of an olefin polymerization stage in a fluidized bed gas-phase reactor, in which heat is transferred from a circulating gas stream taken from the top of the fluidized bed gas-phase reactor to a first cooling fluid in a first heat exchange step (GPR precooler). The circulating gas is then led to a second heat exchange step (circulating gas cooler) where the residual heat of the circulating gas is transferred to a second cooling medium (not shown). The cooled circulating gas is then transferred to the bottom of the fluidized bed gas-phase reactor. In some embodiments, the first cooling medium is preferably heated in the GPR precooler so that the first cooling medium undergoes a phase transition from liquid to gas phase. The heated first cooling medium is pressurized in a heat pump compressor and led to a heat exchanger where the heat of the pressurized and heated first cooling fluid is transferred to an aqueous condensate. The aqueous condensate is thereby vaporized to produce low pressure steam, which can then be used for energy recovery. The first cooling medium cooled in the heat exchange process is then expanded as it passes through a valve and transferred to the GPR precooler as the first cooling medium.

[0097] Figure 4 shows a proposed example of the embodiment of Figure 3. This example is proposed using ASPEN Plus. In the first heat exchanger (left side) a hot fluid stream is cooled, such as a polymer slurry from a loop reactor or a circulating gas stream from a gas phase reactor. The hot fluid stream is introduced into the first heat exchanger with a flow rate of 1400 t / h and has a pressure of 21 barg. The first cooling medium is n-pentane. A liquid n-pentane stream is introduced into the first heat exchanger with a flow rate of 111 t / h, a temperature of about 65° C. and a pressure of about 1.45 barg (not shown). The heated n-pentane stream removed from the first heat exchanger with a flow rate of 111 t / h undergoes a phase transition from liquid to gas phase and has a temperature of 65° C. and a pressure of 1.4 barg. The power of the first heat exchanger is 5450 kW. The heated n-pentane gas stream is then passed through a suction drum and introduced into a preheater for further heating the heated n-pentane gas stream to a temperature of 95° C. and a pressure of 1.2 barg at a flow rate of 111 t / h. The heating medium in this preheating step is a cooled n-pentane gas stream taken from a steam boiler (see below), which is cooled to a temperature of 123° C. and a pressure of 14.7 barg before being introduced into the first heat exchanger at a flow rate of 111 t / h. The heating duty of the preheater is 1880 kW. The heated n-pentane gas stream taken from the preheater is then compressed and further heated in the heat pump compressor at a temperature of 158° C. and a pressure of 15.5 barg with a flow rate of 111 t / h. The power of the heat pump compressor is 3000 kW. The heated and compressed n-pentane gas stream is introduced into a steam boiler where heat is transferred from the heated and compressed n-pentane gas stream to an aqueous condensate stream. Before being introduced into the steam boiler, the aqueous condensate can be preheated, for example with a hot n-pentane liquid stream (not shown), to improve energy efficiency. The aqueous condensate stream introduced into the steam boiler at a flow rate of 12 t / h has a temperature of 80° C. and a pressure of 3.4 barg. In the steam boiler, the aqueous condensate is vaporized into a steam stream which is withdrawn from the steam boiler at a flow rate of 12 t / h and has a temperature of 145° C. and a pressure of 3.1 barg. This steam stream can be used for energy recovery. The cooled pentane gas stream is withdrawn from the steam boiler at a flow rate of 111 t / h and has a temperature of 142° C. and a pressure of 14.9 barg. The heating load of the steam boiler is 8340 kW. The cooled pentane gas stream removed from the steam boiler is transferred through a discharge drum and introduced into a precooler for heating the heated n-pentane gas stream removed from the first heat exchanger (see above), thereby further cooling the cooled pentane gas stream. Before entering the first heat exchanger as a cooling medium for the hot fluid stream (see above), the n-pentane gas stream is subjected to a further cooling step (not shown) to effect a phase transition from gas phase to liquid. The liquid n-pentane stream has a temperature of about 65° C. and a pressure of about 1.45 barg (not shown) before being introduced into the first heat exchanger. The electricity consumed in this process scenario is approximately 3000 kW. The process side cooling duty is approximately 5450kW. The load (heat exchange amount, duty) for steam generation is approximately 8345kW. The COP is approximately 2.763.

[0098] Figure 5 shows a proposed example of a further embodiment of the heat recovery method of the present invention, in which a low pressure steam stream obtained from a steam boiler as exemplarily discussed in the embodiment of Figure 4 is subjected to a further compression step in a steam drum or attemperator to produce a steam stream having a temperature and pressure in the range required for direct use in a polymerization process. This example has been proposed using ASPEN Plus. A conventional heat pump compressor provides a pressurized and heated n-pentane gas stream which is used to heat and vaporize the aqueous condensate stream into a low pressure steam stream having a temperature of 130° C. and a pressure of 1.62 barg. This low pressure steam stream is then further compressed in a steam drum or attemperator to a temperature of 154° C. and a pressure of 5.4 barg at a flow rate of 12 t / h for further use in the polymerization process. The power of the heat pump compressor is 3557kW. The coefficient of performance (COP) is 2.356.

[0099] Figure 6 shows a proposed example of a further embodiment of the heat recovery method of the present invention, in which a low pressure steam stream obtained from a steam boiler as exemplarily discussed in the embodiment of Figure 4 is subjected to a further compression step in a compressor heat pump adapted to produce a steam stream having a temperature and pressure in the range required for direct use in a polymerization process. This example has been proposed using ASPEN Plus. The heat pump compressor is fitted with an additional water vapor compressor, and the low pressure water vapor stream from the embodiment of Figure 5 having a temperature of 130°C and a pressure of 1.62 barg is instead introduced into said additional water vapor compressor of the heat pump compressor to generate a water vapor stream having a temperature of 154°C and a pressure of 5.4 barg with a flow rate of 12 t / h for further use in the polymerization process. The power of the adapted heat pump compressor is 2778 kW. The coefficient of performance (COP) is 2.830. Use of the adapted heat pump compressor of Figure 6 to provide 12 t / h of a 154°C and 4.2 barg water vapour stream and n-pentane as the first cooling medium provides the following advantages compared to using a conventional heat pump compressor with a water vapour drum or attemperator of Figure 5: Reduced power required: -779kW Energy savings: -21% ·COP improvement: 20.1%

Claims

1. 1. A method for energy recovery, comprising: a) providing a hot fluid stream; b) placing the hot fluid stream in thermal contact with a first heat transfer fluid in a first heat exchanger, thereby transferring heat from the hot fluid stream to the first heat transfer fluid, generating a temperature T １ and pressure p １ obtaining a heated first heat transfer fluid having c) subjecting the heated first heat transfer fluid to at least one, for example 1 to 5, preferably 2 to 4, most preferably 2 or 3 compression steps to a pressure p ２ obtaining a compressed first heat transfer fluid having d) thermally contacting the compressed first heat transfer fluid with an aqueous condensate in a second heat exchanger, thereby transferring heat from the compressed first heat transfer fluid to the aqueous condensate and vaporizing the aqueous condensate to obtain a water vapor stream; e) using said water vapor stream for energy recovery, thereby obtaining a stream comprising an aqueous condensate; Including, Pressure p １ Pressure p ２ The ratio of p ２ / p １ is between 5 and 50, The water vapor stream used for energy recovery has a temperature T ｓ is in the range of 120 to 200° C., preferably 130 to 170° C., more preferably 135 to 150° C., and the pressure p ｓ is in the range of 2.0 to 15.5 barg, preferably 2.7 to 7.9 barg, more preferably 3.1 to 4.8 barg.

2. The hot fluid stream has a temperature T ｆ 2. The method of claim 1, comprising:

3. 3. The method according to claim 1 or claim 2, wherein the first heat transfer fluid is selected from a refrigerant selected from hydrocarbons such as propane, isobutene, n-butane, cyclopropane, ethane, n-pentane, isopentane, cyclopentane or mixtures thereof, halogenated hydrocarbons such as hydrochlorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons or mixtures thereof such as methyl chloride, dichloromethane, monofluorodichloromethane, monochlorodifluoromethane, trichlorotrifluoroethane, 1,2-dichlorotetrafluoroethane, 2,2-dichloro-1,1,1-trifluoroethane, 1,1-difluoromethane or mixtures thereof, natural refrigerants such as ammonia, carbon dioxide or sulphur dioxide, or nanofluids.

4. The first heat transfer fluid before entering the first heat exchanger is liquid and has a temperature T of 15 to 75° C., more preferably 20 to 72° C., and most preferably 25 to 70° C. ０ The method according to any one of claims 1 to 3, comprising:

5. In step b), the first heat transfer fluid is vaporized and heated to a temperature T １ and pressure p １ 5. The method according to claim 1, wherein a vaporized heated first heat transfer fluid having

6. T １ is in the range of 30 to 80° C., preferably 40 to 75° C., more preferably 50 to 70° C., and / or the pressure p １ A process according to any one of claims 1 to 5, wherein the pressure is in the range of 0.5 to 2.0 barg, preferably 0.7 to 1.8 barg, more preferably 1.0 to 1.5 barg.

7. Pressure p ２ A process according to any one of claims 1 to 6, wherein the pressure is in the range of 10.0 to 20.0 barg, preferably 12.0 to 18.0 barg, more preferably 14.0 to 16.0 barg.

8. In the at least one compression step c), the temperature of the heated first heat transfer fluid is increased to a temperature T ２ The temperature is raised to T ２ is the temperature T １ The method according to any one of claims 1 to 7, wherein the temperature is 50K to 250K, preferably 65K to 150K, most preferably 75K to 125K higher than the temperature.

9. 9. The method according to claim 1, wherein the first heat transfer fluid removed from the second heat exchanger in step d) is transferred to the first heat exchanger and used as the first heat transfer fluid in step b).

10. The water vapor stream is compressed in at least one, for example 1 to 5, preferably 2 to 4, and most preferably 2 or 3 compression steps to a temperature T ｓ and pressure p ｓ 10. The method according to claim 1, wherein a compressed water vapor stream having

11. 11. The method according to any one of claims 1 to 10, wherein the aqueous condensate obtained from the spent water vapor stream is used to thermally contact the compressed first heat transfer fluid with the aqueous condensate in the second heat exchanger.

12. 1. An installation for energy recovery, comprising:

3. Transferring heat from the hot fluid stream to a first heat transfer fluid at temperature T １ and pressure p １ a first heat exchanger for obtaining a heated first heat transfer fluid having a first heat transfer fluid having a first heat transfer fluid having a first heat transfer fluid; One or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, of the heated first heat transfer fluids connected in series are compressed to a pressure p ２ means for obtaining a compressed first heat transfer fluid having a first heat transfer fluid pressure of at least 1000 MPa, preferably at least one, e.g. one or two, preferably one heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series; a second heat exchanger for transferring heat from the compressed first heat transfer fluid to an aqueous condensate to obtain a water vapor stream; means for using said water vapor stream for energy recovery thereby obtaining a stream comprising an aqueous condensate; means for transporting the heated first heat transfer fluid from the first heat exchanger to a first upstream means for compressing the heated first heat transfer fluid; Optionally, means for transporting said compressed first heat transfer fluid from one upstream means for compressing said heated first heat transfer fluid to a next downstream means for compressing said heated first heat transfer fluid in the series of said means for compressing said heated first heat transfer fluid; Pressure p ２ a means for transporting the compressed first heat transfer fluid from a last in a series of the means for compressing the heated first heat transfer fluid to the second heat exchanger; means for transporting said aqueous condensate to said second heat exchanger; means for transporting said water vapor stream from said second heat exchanger to said means for using said water vapor stream for energy recovery; Including, facilities.

13. One or more, preferably 1 to 5, more preferably 1 to 3, and most preferably 1 or 2, steam streams connected in series are compressed to a temperature T ｓ and pressure p ｓ means for obtaining a water vapor stream having the formula: means for transporting said water vapor stream from said second heat exchanger to a first upstream means for compressing said water vapor stream; Optionally, means for transporting said water vapor stream from one upstream means for compressing said water vapor stream to a next downstream means for compressing said water vapor stream in a series of said means for compressing said water vapor stream; Temperature T ｓ and pressure p ｓ means for transporting said water vapor stream from a last in a series of said means for compressing said water vapor stream to said means for using said water vapor stream for energy recovery; The facility of claim 12 further comprising:

14. The one or more, preferably 1 to 5, more preferably 1 to 3, and most preferably 1 or 2, temperature T １ and pressure p １ to compress the heated first heat transfer fluid having a pressure p ２ and one or more, preferably 1 to 5, more preferably 1 to 3, and most preferably 1 or 2, of said steam streams connected in series to obtain a compressed first heat transfer fluid having a temperature T ｓ and pressure p ｓ 14. The installation of claim 13, wherein the means for obtaining a compressed water vapor stream having a pressure of from about 1000 to about 1000 MPa is a compression stage of the same heat pump compressor.

15. means for transporting said first heat transfer fluid from said second heat exchanger to said first heat exchanger; The installation according to any one of claims 12 to 14, further comprising:

16. 16. The installation of any one of claims 12 to 15, wherein the means for transporting the aqueous condensate to the second heat exchanger is means for transporting the aqueous condensate from the means for using the water vapor stream to the second heat exchanger.

17. one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3, means for compressing the heated first heat transfer fluid, preferably at least one, e.g. 1 or 2, preferably 1 heat pump compressor, each heat pump compressor comprising one or more, preferably 1 to 5, more preferably 2 to 4, most preferably 2 or 3 compression stages connected in series, the temperature T １ and pressure p １ to compress the heated first heat transfer fluid having a pressure p ２ 16. Use of a method according to any one of claims 1 to 11 or an installation according to any one of claims 12 to 15 to obtain a compressed first heat transfer fluid having

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