WO2024061705A1 - Machine and method for the operation thereof for producing or treating a fibrous web, said machine having a heat pump - Google Patents

Abstract

The invention relates to a machine (1) and a method for producing or treating a fibrous web (F), in particular a paper, board or tissue web (F), comprising at least one machine section (2, 3, 4), preferably a dryer section (2, 4) or forming section (3), at least one thermal-energy load, preferably a steam and condensate system (5) and/or a secondary system load (70, 71, 82), and at least one thermal-energy recovery system (6), wherein a heat pump (90) extracts residual thermal energy from an exhaust-air flow of at least one exhaust-air line (84, 84') from at least one machine section (2, 3, 4) and, being additionally fed electrical energy (80), feeds thermal energy to the at least one thermal-energy load (5, 70, 71, 82), preferably to a condensate of the at least one condensate return line (58). According to the invention, the heat pump (90) is disposed in the exhaust-air line (84) such that the heat pump (90) recovers the residual thermal energy before a dew point temperature of the exhaust-air flow in the exhaust-air line (84, 84') is reached, and the steam and condensate system (5) comprises a steam accumulator (54) for storing the steam, said steam accumulator being downstream of the heat pump (90).

Description

Machine and method for its operation for the production or treatment of a fibrous web with a heat pump

The invention relates to a machine for producing or treating a fibrous web, in particular a paper, cardboard or tissue web, comprising at least one machine section, preferably a drying section or forming section, and at least one heat energy consumer, preferably a steam and condensate system and/or a secondary system consumer , and at least one thermal energy recovery system, and wherein the at least one machine section comprises at least one exhaust air line, and wherein the thermal energy recovery system is arranged in the at least one exhaust air line and comprises at least one heat pump, and wherein the at least one machine section and the at least, a heat energy consumer is in an operative connection via the at least one heat energy recovery system, such that the heat pump partially removes residual heat energy from an exhaust air stream of the at least one exhaust air line and, with an additional supply of electrical energy, from a heating medium stream supplies heat energy to a heat energy consumer.

The invention also relates to a method for use in a machine according to the invention.

The document DE102015219379 A1, discloses a machine and a method for operating a machine, wherein a medium for drying a fibrous web is supplied to a drying area and the medium is removed from the drying area downstream of the drying area and supplied as a heat source to a heat pump, by means of which a second medium is heated and fed further downstream to a smoothing cylinder within the drying area.

The document DE102015219381 A1, discloses a machine and a method for operating a machine, wherein a medium for drying a fibrous web is supplied to a drying area and the medium is discharged from the drying area downstream of the drying area and as a heat source of a heat pump is supplied, by means of which the same medium is heated with the addition of further energy and is fed back to the drying area at the beginning.

Document W02020 079326 A1 discloses a heat pump insert in a recirculation system and an air recirculation process for a drying section of a cardboard or machine. The system includes at least three air return parts connected one behind the other to a drying section hood in the direction of travel of a web-shaped material. Each circulating air section includes one or more heat recovery units. Each heat recovery unit includes a circulating air fan for sucking in moist exhaust air from the dry section hood through the heat recovery unit and for supplying at least a portion of the conditioned moist exhaust air to the dry section hood and an air-fluid heat exchanger for conditioning the moist exhaust air by cooling and reducing a moisture content of the moist exhaust air.

The document DE10 2007 051165 A1 discloses a machine and a method with a wet section and a dry section, with a drying section and a drying section hood for the paper web being provided in the dry section. Energy from the exhaust air from the drying section is used to heat supply air in a heating device arranged in the wet section via a heat pump.

The document DE2630853 A1, 1976, discloses a drying section for a machine, wherein a heat pump is connected between the input line with fresh, hot supply air and the output line with moist exhaust air, thereby recovering energy from the exhaust air and transferring the energy to the input line of the drying section is made possible.

Various drying devices are used to dry fibrous webs or tissue papers in the paper industry. These include, for example, contact drying sections or non-contact drying sections. The contact drying lines include, for example, single-row, double-row drying cylinder drying lines and non-contact drying lines for example air drying devices or infrared drying lines. The generation of heat in the form of hot air for the drying sections is typically done either by steam heating registers, preferably high-pressure steam heating registers, or gas burners. If steam is used, such as in steam-heated drying cylinders, it is often taken from a fossil fuel-fired steam generator, for example a gas and steam power plant (CCPP power plant). The hot air usually has an inlet temperature of greater than 180°C, sometimes only greater than 100°C and can, for example, be up to 650°C. In the lower temperature range, steam air heaters, thermal oil air heaters or gas burners are usually used, in the upper temperature range mainly gas burners and, more rarely, thermal oil air heaters. The hot steam usually has temperatures greater than 110°C and less than 150°C.

However, the previous solutions mentioned have a number of disadvantages. The solutions mentioned in the prior art show the use of a heat pump within a drying section, partly in a recirculation mode, which is an unfavorable arrangement from an energetic point of view. The medium for drying a fibrous web in a drying section requires a high level of heat energy; after the initial cooling by the drying section, further extracting heat energy from this medium using a heat pump and increasing it again to supply a drying section or another system with electrical energy means, to increase the heat energy required at the beginning of the drying section and to have to supply more initial heat energy compared to direct recirculation.

The heat pump arrangements shown in a heat energy recovery system of a drying section are significantly more efficient, since the heat energy cannot actually be used for the drying section, which operates at a higher temperature level. The recovery of thermal energy and supply from the drying hood supply air heating is achieved via sometimes complex heat systems. Another disadvantageous aspect is that the heat pumps are limited in providing the required increased energy levels from the point of view of an efficient operating point (COP). If you still want to achieve acceptable efficiency values, this results in a limited heating temperature by the heat pump.

The machines also have a high demand for fossil fuels, especially natural gas, for drying the fibrous web, with the expected disadvantages in terms of costs. The rising procurement costs and the increasingly strict CO2 regulations and CO2 taxes account for a decisive share of the manufacturing costs. Furthermore, due to global crises, availability and reputation with regard to the impact on the global climate are often other important aspects.

As part of decarbonization, it would be ideal to use a heat pump to supply the dryer sections alone, but this poses some challenges for the correct arrangement of the heat pump in the machine and also for the operation of a paper machine. Normally, for economic reasons, the paper machines are operated around the clock, so to speak, in normal operation. Now, during normal operation, unforeseen errors such as a web break can occur again and again or planned short downtimes can occur, for example when changing grades or minor maintenance work. These short downtimes usually last from a few hours to a maximum of three days. The systems and parts of the machine usually do not cool down completely, but they lose some of their thermal energy and this is referred to as a warm start when the machine is started up again. During a warm start, the heat pump in use can only generate the larger temperature differences that are present very inefficiently or not at all compared to normal operation. Another problem is the major downtime that usually occurs every year for pending maintenance or a major overhaul of the machine, whereby the machine cools down completely over several days or weeks and the paper machine and the associated paper machines Components must be completely heated from ambient temperature to an operating temperature; a so-called cold start requires significantly more heat energy, for which supply from a heat pump alone is not sufficient.

The inventors have recognized that an advantageous arrangement in the machine and an optimized process for operation can eliminate the disadvantages.

The object of the invention is to provide a machine and a method for the production and/or treatment of a fibrous web, in particular paper, cardboard or tissue web, with a heat pump, the heat energy required for the drying section being supplied primarily, preferably solely during normal operation an improved arrangement of a heat pump in the heat energy recovery system of an exhaust air is provided in an energetically efficient manner.

A further object of the invention is to provide an efficient solution for the provision of the thermal energy in an exceptional operating case such as a cold start or a warm start for the operation of the machine with the sole provision of the required thermal energy by a heat pump in normal operation.

A further object of the invention is to significantly reduce and/or completely eliminate the need for fossil fuels, in particular natural gas, when drying a fibrous web. This significantly reduces operating costs, as well as the risk of dependence on a consumption medium or supplier.

The object is achieved according to the invention by a machine and a method according to the independent claims. Further advantageous embodiments of the present invention can be found in the subclaims

The machine according to the invention is characterized in that the at least heat pump is arranged in the exhaust air line in such a way that the heat pump is in front of When the exhaust air flow reaches a dew point temperature, the remaining heat energy is recovered in the exhaust air line.

Arranging the heat pump before the dew point temperature of the exhaust air stream is reached means that when the exhaust air stream enters or enters the heat pump, it is higher than the dew point temperature of the exhaust air stream, and thereby the heat pump succeeds in reducing the temperature and remaining heat energy of available exhaust air to such an extent that at least some, preferably all, of the moisture absorbed by it during the drying process condenses in the heat pump. In other words, the exhaust air stream used is cooled below the dew point temperature as it flows through the heat pump. On the other hand, the exhaust air flowing through the output line is transferred at a higher level into a heat consumer circuit, for example a steam and condensate system and/or a secondary system consumer. The heat energy requirement for drying can be achieved completely electrically or with non-fossil fuels with lower energy consumption. Because moisture is removed from the exhaust air in the form of condensation, e.g. B. in the case of a paper factory mentioned, there is a significant saving in water requirements. At the same time, the environmental impact is reduced, which in many cases is caused by the rising clouds of steam caused by the moist exhaust air.

The heat energy required for evaporation is advantageously obtained solely or at least in part from the exhaust air from various machine sections. The drying section with its various drying sections with the highest amounts of residual heat in the exhaust air is primarily important, and large amounts of exhaust air can also advantageously be obtained from the usually included vacuum blowers in the drying sections or also for very large quantities of vacuum blowers in the forming section. The exhaust air is recovered using a heat pump. The thermal energy contained in the exhaust air can be further recovered using multi-stage thermal energy recovery, for example plate or tube bundle heat exchangers, and used to supply secondary system consumers, such as dry hood supply air heating, process water heating or heating water heating used. The heat exchangers are arranged in the order of the temperature levels of the consumers to be supplied in order to keep the heating surfaces and costs of the heat exchangers as small as possible.

It is also advantageous if the steam and condensate system includes a steam storage unit downstream of the heat pump for storing the steam.

Advantageously, the steam accumulator can temporarily store a sufficient amount of steam at a steam temperature. This temporary storage enables an advantageous bridging of periods during a warm start or possibly even a cold start of the machine in which the heat pump will only work to a limited extent efficiently or inefficiently or is not able to provide the required temperature level without the presence of residual exhaust air.

In an alternative embodiment, the machine is characterized in that the heat pump is preceded by at least one further heat exchanger in the exhaust air line, preferably an air-air heat exchanger or an air-heat transfer medium heat exchanger.

In an alternative embodiment, the machine is characterized in that the heat pump is preceded by a further heat exchanger in the exhaust air line, preferably an air-heat transfer medium heat exchanger, in particular an air-water heat exchanger, such that the heat pump comes from a separate heat transfer medium intermediate circuit recovers the heat.

In an alternative embodiment, the machine is characterized in that the heat pump is arranged in such a way that thermal energy is generated at a temperature of the exhaust air stream in the exhaust air line of greater than or equal to 45 ° C, preferably greater than or equal to 60 ° C, and less than or equal to 80 °, preferably less than or equal to 70°C.

In an alternative embodiment, the machine is characterized in that the heat pump is designed in such a way that during normal operation of the machine required steam requirement, preferably a steam temperature and a steam mass flow, in the steam and condensate system is provided solely by the heat pump.

In an alternative embodiment, the machine is characterized in that the heat pump is followed by a steam generator included in the steam and condensate system, preferably a passively functioning or electrically operated steam generator, which is designed to convert a condensate heated to steam temperature by the heat pump into steam.

Advantageously, a steam generator is used downstream of the heat pump, which generates steam from the condensate heated by the heat pump with only a small supply or no supply of additional energy. For example, a passive steam generator can be a throttle through which the heated condensate undergoes flash evaporation.

In an alternative embodiment, the machine is characterized in that the steam storage comprises an electrical heating device or a hydrogen burner heating device for maintaining a steam temperature.

In an alternative embodiment, the machine is characterized in that the steam accumulator is designed in such a way that the steam accumulator has a steam storage period of greater than or equal to 8 hours, preferably greater than or equal to 12 hours, in particular greater than or equal to 72 hours, in order to solely supply the required steam Amount of steam when the machine is started warm.

In an alternative embodiment, the machine is characterized in that the steam accumulator is designed in such a way that the steam accumulator produces steam at a steam temperature of greater than or equal to 110 ° C and a steam pressure level of greater than or equal to 0.4 and less than or equal to 1. 5 bar above atmospheric pressure. In an alternative embodiment, the machine is characterized in that the steam and condensate system comprises at least one electrically operated steam compressor, preferably two, three or four electrically operated steam compressors connected in series, designed in such a way that a steam in the steam supply line to a steam pressure level of greater than or equal to 5, preferably greater than or equal to 6 and less than or equal to 12, preferably less than or equal to 10, bar above atmospheric pressure.

The steam compressors used are designed as electrically driven, pure compressor units and serve to further compress the steam present. These steam compressors differ from the so-called thermal compressors commonly used in paper machines.

In an alternative embodiment, the machine is characterized in that the steam and condensate system comprises a further steam generator, preferably a mobile steam generator, which is designed in such a way that a short-term steam requirement, preferably a steam temperature, is required for the duration of a cold start of the machine and a steam mass flow is provided in the steam and condensate system only until an operating temperature for normal operation of the machine is reached.

In an alternative embodiment, the machine is characterized in that the exhaust air line can be connected to a drying hood of a drying section, a drying hood of a Yankee drying cylinder, a drying hood of a contactless drying section, a vacuum blower of a drying section and/or a vacuum blower of a forming section.

The method according to the invention for producing or treating a fibrous web, in particular a paper, cardboard or tissue web, in a machine according to claim 1, is characterized in that the heat pump before reaching a dew point temperature of the exhaust air flow in the exhaust air line recovers the remaining heat energy and that a steam into one of the Steam storage downstream of the heat pump is stored and that a set steam requirement of the steam and condensate system is a) provided solely by the heat pump during normal operation of the machine, and b) is provided solely by the steam storage in the steam and condensate system during a warm start of the machine.

In a further alternative embodiment, the method is additionally characterized in that c) during a cold start of the machine, a further steam generator, preferably a mobile further steam generator, is arranged in the steam and condensate system in such a way that the required steam requirement is met by the further steam generator for normal operation of the machine is provided alone and/or in addition to the heat pump.

In an alternative embodiment, the machine is characterized in that the heat pump is arranged in such a way that a heating medium flow, preferably a condensate, in a condensate return line of the steam and condensate system, has a temperature difference of greater than or equal to 15 ° K, preferably greater than or equal to 40°K, preferably greater than or equal to 60°K.

In an alternative embodiment, the machine is characterized in that the steam storage is designed as a boiling water storage, preferably a Ruth steam storage.

In an alternative embodiment, the machine is characterized in that the steam and condensate system comprises a mixing line downstream of the steam compressor and that the mixing line is connectable to a low-pressure area for mixing the steam to a set steam pressure level.

In an alternative embodiment, the machine is characterized in that the steam and condensate system includes another steam generator, preferably a further mobile steam generator heated with non-fossil fuels, preferably a further mobile steam generator heated with hydrogen, biogas, geothermally, solar and/or electrically heated.

The invention also expressly extends to those embodiments which are not given by combinations of features from explicit references to the claims, with which the disclosed features of the invention can be combined with one another - to the extent that this makes technical sense.

Corresponding elements of the exemplary embodiments in the figures are provided with the same reference numbers. The functions of such elements in the individual figures correspond to one another unless otherwise described and this does not lead to contradictions. A repeated description is therefore omitted.

It is also pointed out that the different features of the exemplary embodiments shown can be exchanged for one another and combined with one another. The invention is therefore not limited to the combinations of features shown in the exemplary embodiments shown.

Further features and advantages of the invention result from the following description of preferred exemplary embodiments with reference to the drawings.

In the following, the invention is explained with reference to the following figures.

Figures 1a to 1d show schematically illustrated arrangements of the machine according to the invention with a heat pump and a steam accumulator;

Figure 2 shows a schematic cross section through a heat pump designed as a compression heat pump;

Figures 3a to 3e show further schematic arrangements of the machine with a heat pump. Figures 1a and 3a illustrate, in a schematic and highly simplified representation, the basic structure and the basic function of a machine 1 designed according to the invention for producing or treating a fibrous web F, in particular a paper, cardboard or tissue web F with a heat pump 90 and a steam accumulator 54.

The machine 1 comprises at least one drying section 2, 4. In the exemplary arrangement, two drying sections 2, 4 are shown, with at least one further machine section 3 being arranged between the two drying sections 2, 4. This is, for example, an application device or a calender. The machine 1 is shown schematically and in a very simplified manner and is only shown with regard to the components relevant to the invention. The usual other upstream and downstream parts or components of a machine 1 for producing or treating a fibrous web F, such as a headbox, a former, a press, an applicator, a calender, a smoothing device and a reel are not shown because these are assumed to be known. After leaving the last drying section 4, the fibrous web F is usually transferred to a subsequent machine section such as a smoothing device and/or the rewinder.

To clarify the individual directions, a Cartesian coordinate system has been created, which can be used to illustrate the individual directions. The x-direction illustrates the extension in the longitudinal direction, which is also referred to as the machine direction MD (Machine Direction). The y-direction corresponds to the direction perpendicular to the machine direction and is called the CD (cross-direction), while the z-direction corresponds to the height direction.

The flow directions of the various media are illustrated in the figures by a directional arrow in the lines.

The fibrous web F usually enters a first drying section 2 shown, the first drying section 2 is divided into several drying sections 21, 22, 23 and a total of five drying sections 21, 22, 23 are shown. The drying sections in the first drying section 2 are further covered by two drying hoods 29 enclosed, which collect or capture the unused heat energy released in the drying sections in the form of exhaust air.

The machine 1 further comprises a steam and condensate system 5 and a heat energy recovery system 6. The steam and condensate system 5 is usually used to supply the drying sections 2, 4 with heat in the form of heated, superheated and/or heated steam. The steam and condensate system 5 can be connected to the drying section 2, 4 and/or the drying sections 21, 22, 23, 41 via a steam supply line 57 and a condensate return line 58. The steam and condensate system 5 usually provides steam with maximum temperatures T_57 of greater than or equal to 100 ° C to less than or equal to 130 ° C and a volume or mass flow to supply the drying section 2, 4. The steam used in the drying section 2, 4 is returned in the form of condensate in a condensate return line 58 in the closed steam and condensate system 5. The condensate usually has a return temperature of T_58 of greater than or equal to 90°C to less than or equal to 100°C.

Furthermore, a drying section 21 within the first drying section 2 is shown with a further drying hood 291. This can be, for example, a drying section 21, which is designed as a contactless drying section 21, such as an impingement flow drying section 21 or an infrared drying section 21 , the contactless drying sections are preferably heated electrically or with hydrogen.

The second drying section 4 is, for example, designed with a single drying section 41 and drying hood 49. This can advantageously be a drying section 41, which is designed as a contactless drying section 41, such as an impingement flow drying section 41, or an infrared drying section, preferably heated electrically or with hydrogen.

The drying section 4 can also be designed, for example, as a high-performance drying hood 49 of a Yankee drying cylinder 41.

The drying section 2, 4 can have different designs and components; for example, combinations or similar designs of the following exemplary embodiments are conceivable. The drying section 2, 4 can, for example, be designed as a single-row and/or double-row drying cylinder drying section 21, 22, 23, 41 with surrounding drying hoods 29, 49. Furthermore, the drying section can, for example, in a tissue machine as a high-performance drying hood 29, 49 on a Yankee drying cylinder, the Yankee drying cylinder forming a drying section 21, 22, 23, 41.

Another possible source for exhaust air 84 in another machine section 3 of the machine 1 is also shown. A forming section 3 usually includes so-called vacuum blowers of the forming section 31 for dewatering the fibrous web F, which provide further exhaust air 84 with residual heat.

The drying hoods 29, 291, 49 shown can be connected to a supply air line 82 and an exhaust air line 84, whereby a warmed fresh air stream 82 is preferably supplied through the supply air line 82 for better absorption of the released moisture. The warmed and moist air caused by the drying of the fibrous web is transported away again through the connected exhaust air line 84.

Several exhaust air lines 84 can advantageously be connected together, for example in order to obtain a larger exhaust air volume flow and/or alternatively, if the heat available is significantly above the temperatures required for efficient heat energy recovery, further blended or mixed in order to provide an optimal initial temperature level with a higher volume flow for efficient heat energy recovery.

For the efficient use of the residual heat, the exhaust air streams 84 are each fed individually to their own heat recovery system 6. Advantageously, each exhaust air line 84 has a separate heat recovery system, which can also be advantageously reconnected and mixed on the consumer side, for example to achieve the desired temperatures in a secondary system consumer 70, 71, 72, 73, 74. Another resulting advantage is that for example if the existing exhaust air volume flows 84, such as in a vacuum blower in a forming section 31, are so large that the dimensioning of the exhaust air lines 84, for example in Diameter, have to be guided over long distances of the machine 1 and become too complex in terms of costs and production technology. Here, a heat exchanger 60, preferably an air-heat transfer medium heat exchanger 60, is connected upstream in an exhaust air line that is kept as short as possible, which advantageously transfers the heat into an intermediate heat transfer circuit 86 with low losses. The heat transfer medium 86, preferably water 86, has a high specific heat capacity compared to the exhaust air, so that transport over larger distances in the machine 1 is easier to implement.

In order to be able to realize a particularly efficient operation of the machine 1, the machine 1 comprises a heat energy recovery system 6 with at least one heat pump 90 for supplying the drying sections 21, 22, 23, 41 included in the drying section 2, 4 with heat, which comes from a Exhaust air line 84, 84 'removes the necessary heat from a machine section. The exhaust air 84, 84' is preferably taken from a drying section 2, 4 and/or directly from a drying section 21, for example an included vacuum suction box or an impingement air or hot air drying section 21. The residual heat or temperatures found there are higher in comparison to other exhaust air streams than, for example, an exhaust air stream 84 of a vacuum blower in a forming section 31. If higher volume flows are required in the exhaust air stream 84, an admixture of different exhaust air lines 84 can advantageously be used take place along the entire thermal energy recovery system / process 6. Ideally, the initial temperatures of the mixed exhaust air streams 84 are still above the dew point, so that the condensation heat contained therein can be advantageously recovered.

Further required supply air is obtained from the environment 88 of the machine 1, the environment having an ambient temperature and an ambient pressure, usually essentially 1 atm (atmosphere) or 1 bar.

The steam and condensate system 5 further comprises a high pressure area 51 and a low pressure area 52, the high pressure area 51 being characterized in that a steam pressure level of greater than or equal to 5, preferably greater than or equal to 6 and less than or equal to 12, preferably less than or equal to 10, bar above atmospheric pressure and in the low pressure area 52 a vapor pressure level of greater than or equal to 0, preferably greater than or equal to 0.4 and less than or equal to 1, preferably less than or equal to 1.5, bar above atmospheric pressure.

The high-pressure area 51 further comprises at least one steam compressor 55, preferably two, three or four series-connected steam compressors 55, which are designed to increase an existing steam pressure level of the low-pressure region 52 to the set steam pressure level of the high-pressure region.

The at least one steam compressor 55, preferably the two, three or four series-connected steam compressors 55, are designed such that a steam in the steam supply line 57 of the drying sections 21, 22, 23, 41 to a steam pressure level of greater equal to 5, preferably greater than or equal to 6 and less than or equal to 12, preferably less than or equal to 10, bar is increased above atmospheric pressure.

Furthermore, the steam and condensate system 5 includes a steam storage 54, wherein the steam storage 54 can be, for example, a boiling water storage, but can also be another form of steam storage to cover the requirements. The steam accumulator 54 is arranged downstream of the heat pump 90.

Advantageously, the steam storage 54 is designed in such a way that it has a storage period of the heated steam of greater than or equal to 8 hours, preferably greater than or equal to 12 hours, in particular greater than or equal to 72 hours.

It is advantageous if the storage period can be achieved without additional heat, i.e. using passive methods. A “storage period” means that the original temperature and pressure of the warmed-up steam is essentially maintained.

This enables short-term, limited bridging of short machine downtimes due to possible errors and/or minor maintenance work.

In an alternative embodiment, the steam accumulator 54 has an electric heating device or a hydrogen burner heating device for maintaining a boiling water temperature. This can be used if the passive methods are not completely sufficient. The steam and condensate system 5 further comprises a steam distributor 50, which can distribute the steam into a high-pressure area 51 and a low-pressure area 52.

Furthermore, the steam and condensate system 5 includes a steam generator 53, wherein the steam generator 53 is arranged downstream of the heat pump 90, and the steam generator 53 is passively or electrically heated, and the steam generator 53 is designed such that the steam generator 53 is heated to over 110 ° C Condensate in the condensate return line 58 'after the heat pump 90 can be converted into steam by supplying little or no electrical energy. The heat pump is usually suitable for achieving a phase transition from liquid condensate to gaseous vapor when the temperature of the condensate from the condensate return line 58 increases to a heated condensate in the condensate return line 58 '. The usual pressure level in the condensate return line 58 'is between 0.4 and 1.5 bar above atmospheric pressure and at a temperature of greater than or equal to 100 ° C to less than or equal to 120 ° C.

In the event of a longer standstill of the machine 1, in an alternative embodiment the steam and condensate system 5 can comprise a further steam generator 56. This can be, for example, a stationary and/or a mobile, temporarily provided additional steam generator 56. The additional steam generator 56 is preferably a steam generator 56 heated with non-fossil fuels, preferably a steam generator 56 heated with hydrogen, with biogas, geothermally, solar and/or electrically.

A separate, mobile additional steam generator 56 can usually be planned and arranged specifically for the required period of time due to the predictability or plannability of a longer standstill; this is advantageous from an economic point of view.

The further steam generator 56 is designed in such a way that the further steam generator 56 can briefly cover the steam requirements of the heat energy consumers 5, 70, 71, 72, 73, 74, 82 for a cold start of the machine 1. This means that a set temperature of the steam and a steam mass flow are provided until the machine 1 reaches an operating temperature. It is also conceivable that the further steam generator 56 is operated in combination with the heat pump 90 in such a way that the further steam generator 56 and the heat pump 90 together briefly control the set temperature and the mass flow of the steam for a cold start of the machine 1 until an operating temperature is reached Prepare machine 1. For example, in a simple case, once a certain temperature level has been reached in the exhaust air lung 84, a linear relationship between the further steam generator and the heat pump can be regulated, so that as the temperature increases until the operating temperature is reached, the heat pump has an increasing share of the steam requirement provides.

The additional steam generator 56 can be arranged directly downstream of the steam storage 54 and feed the steam requirement upstream of a steam compressor in the low-pressure area 52 of the steam and condensate system 5. Advantageously, at least one steam compressor 55, for example shown here with three stages and three steam compressors in series, can then be used to achieve the set steam pressure level, which makes it possible to reduce a mobile steam generator 56 in the required power class.

In an alternative arrangement, the steam generator 56 feeds the required steam completely into the steam and condensate system 5 essentially directly after the steam compressors 55.

The steam and condensate system 5 further comprises a mixing line 59, which connects the high-pressure area 51 and the low-pressure area 52 to a secondary system consumer 70, preferably a secondary steam consumer system. It makes it possible to add steam with a high pressure level to a secondary system consumer 70 after one, preferably after the two, three, or four steam compressors 55 if a certain pressure level between the existing low pressure and high pressure is required. In Figures 1a to 1c, for example, an arrangement with three steam compressors 55 are shown in series.

By using the heat pump 90, a lower temperature T_84' compared to the higher temperature T_84 can be used to further heat the exhaust air in the exhaust air line 84 until a lower temperature 84" is reached. or an ambient temperature T_88 and by means of the extracted heat and use of additional electrical energy 80 to operate the heat pump 90 another media stream 58 in a heating medium supply line 97, preferably a condensate in a condensate return line 58 or a secondary system consumer 70, 71, 72, 73, 74, with a temperature T_97 to a higher temperature T_91 or an increased condensate return temperature 58 '. It applies that the temperature, for example, in the exhaust air line 84 drops after each heat sink or heat exchanger, so a temperature T_84 greater than or equal to T84' greater than or equal to T84" and greater than or equal to T_88 is established. The same applies to the temperatures in the other lines that are routed via a heat sink.

The structure of a heat pump 90 is shown as an example in FIG. The heat pump 90 removes residual heat from a heat source, preferably from an exhaust air stream in an exhaust air line 84, 84 ', 84' or another heat transfer medium 86, 86', preferably water 86, 86', the heat source being supplied via a heat source Supply line 92 and a heat source discharge line 98 can be connected to the first heat exchanger 93 of the heat pump. It is characteristic that the temperature in the heat source supply line T_92 is greater than or equal to the temperature in the heat source discharge line T_98.

The heat pump 90, which can be designed, for example, as a compression heat pump 90, comprises a first heat exchanger 93, which is also referred to as a cold heat exchanger 93 or evaporator 93. Furthermore, the heat pump 90 includes a second heat exchanger 95, which is also referred to as a warm or hot heat exchanger 95 or condenser 95.

When the heat pump 90 is designed as a compression heat pump, the heat pump 90 further comprises a circuit 99 with a heat transport medium and further an evaporator 93, a compressor 94, an expansion element 96 and a capacitor 95. The capacitor 95 is supplied by the medium to be heated or Heating medium, preferably water or condensate in the condensate return line 58, flows through, the capacitor 95 usually being connected to a closed system with a heating medium with a heating medium supply line 97 and a heating medium derivative 91 can be connected or supplied. The heating medium discharge line 91 is connected in such a way that the necessary consumers and/or secondary system consumers are supplied with heat. It is characteristic that the temperature in the heating medium supply line T_97 is less than or equal to the temperature in the outflow line T_91.

The first heat exchanger 95 is, for example, a condenser 95, by means of which the heat transport medium contained in the circuit 99 of the heat pump 90 is condensed. The heat transport medium is relaxed by means of the expansion element 96, the second heat exchanger 93 being, for example, an evaporator 93, by means of which the heat transport medium is evaporated. Finally, the heat transport medium can be compressed again using the compressor 94. To drive the compressor 94, the motor is supplied with electrical energy, so that the heat transport medium can be compressed and thereby heated by means of the compressor 94 using electrical energy 80 or electrical current 80.

As shown, the first heat exchanger 93 can alternatively be connected by different media streams 84, 86, preferably air and/or water, or media streams with different temperature levels 84, 84' from which residual heat is to be recovered.

Alternatively, the first heat exchanger 93 can also be a component of an upstream, separate further heat exchanger 60, 61 or a separate air heater.

Alternatively, the second heat exchanger 95 can also be a component of a downstream, separate, further heat exchanger 60, 61 or a separate air heater.

Furthermore, it is conceivable that the heat pump 90 is designed as a thermochemical heat pump 90. In the thermochemical heat pump 90, a chemical, heat-absorbing and thus endothermic reaction is brought about by means of heat that is supplied to the heat pump 90.

Figure 1a shows an arrangement of the heat pump 90 within the heat energy recovery system 6 marked with a dashed box. The exhaust air line 84 from the machine 1 with a usual temperature of greater than or equal to 75 ° C to 90 ° C is fed to a first heat exchanger 60 arranged upstream of the heat pump 90. In the arrangement shown, a first part of the residual heat still contained in the exhaust air 84 is transferred to the supply air 82 or supply air line 82 flowing in from the surroundings of the machine 1.

In this arrangement, the upstream or first heat exchanger 60 is advantageously designed as an air-air heat exchanger 60.

The exhaust air 84' leaving the first heat exchanger 60 now has a lower temperature T_84' than the temperature T_84 of the incoming exhaust air 84.

The exhaust air flow 84' conducted via the first, upstream heat exchanger 60 is now fed to the heat pump 90, or to the first heat exchanger 93 of the heat pump 90, via the heat source supply line 92, and thus a further part of the residual heat still contained in the exhaust air 84' is further utilized.

At the same time, the heating medium to be heated is supplied to the heat pump 90 through the condensate return line 58 at a temperature T_58 via the heating medium supply line 97. By simultaneously supplying electrical energy 80, the heating medium is heated by the heat pump 90 to a higher temperature level T_58 'in the heating medium discharge line 91 and the exhaust air 84' is cooled to a lower temperature, here to ambient temperature T_88, or through the heat source discharge line 98 derived into the environment 88.

Advantageously, the heat pump 90 is suitable for recovering thermal energy at a temperature T_84 in the exhaust air line 84 of greater than or equal to 55° C., preferably greater than or equal to 60° C., and less than or equal to 80°, preferably less than or equal to 70° C., in a particularly energy-efficient manner

The heated heating medium 58', preferably the condensate, is provided to the steam and condensate system 5 at a set temperature level T_58' of greater than or equal to 100°C, preferably greater than or equal to 110°C, and less than or equal to 130°C, preferably less than or equal to 120°C .

The heat pump 90 is suitable for increasing a temperature of a condensate in the condensate return line 58 by a temperature difference of greater than or equal to 40°K, preferably greater than or equal to 60°K. Figure 1 b only shows the area of the heat energy recovery system 6 and the steam and condensate system 5 and the corresponding supply lines and discharge lines, which are included in the machine 1, as shown in Figure 1 a. 1 b further shows an arrangement of the heat pump 90 within the heat energy recovery system 6 marked with a dashed box, the steam storage 54 being arranged essentially directly downstream of the heat pump 90 and therefore having no further steam generator 53, as shown in FIG. 1 a. Furthermore, an alternative arrangement of the, preferably mobile, additional steam generator 56 in the high-pressure area 51 after the last steam compressor 55 is shown. Furthermore, a second thermal energy recovery system 6 is shown, marked with another dashed box. The second heat energy recovery system 6 for a second secondary system consumer 71 includes a further heat exchanger 62, which transfers the heat of the steam to a further separate secondary system consumer circuit. This can advantageously be a system guided by air or water. The steam conducted via the further heat exchanger 62 is fed to the condensate return line 58 via a recirculation line and is thus heated again via the heat pump arrangement.

Furthermore, the exhaust air line 84 from the machine 1 with a usual temperature of greater than or equal to 75 ° C to 90 ° C is fed to a first heat exchanger 60 arranged upstream of the heat pump 90. In the arrangement shown, a first part of the residual heat still contained in the exhaust air 84 is transferred to the supply air 82 or supply air line 82 flowing from the environment of the machine 1, which is supplied from the environment 88.

The exhaust air 84' leaving the first heat exchanger 60 now has a lower temperature T_84' than the temperature T_84 of the incoming exhaust air 84. Advantageously, in this arrangement, the upstream or first heat exchanger 60 is designed as an air-air heat exchanger 60.

The exhaust air stream 84' conducted via the first, upstream heat exchanger 60 is further conducted downstream via a further, second heat exchanger 61, which is advantageously designed as an air heat transfer medium, heat exchanger 61. The second heat exchanger 61 transfers the residual heat contained in the exhaust air 84' to a separate, preferably closed, heat transfer medium intermediate circuit 86, 86 '. The heat transfer medium 86 can advantageously be water or a heat transfer medium with a high heat capacity.

The heat transfer medium intermediate circuit 86, 86 'is now supplied to the heat pump 90, or to the first heat exchanger 93 of the heat pump 90 via the heat source supply line 92 and thus a further part of the exhaust air 84' still contained in front of the second heat exchanger 61 and Residual heat transferred to the separate heat transfer medium intermediate circuit 86 is further used.

Advantageously, the arrangement from Figure 1 b with a second, intermediate heat exchanger 61 and with a closed, heat transfer medium intermediate circuit 86, 86 'in front of the heat pump 90 is selected when a condition of the exhaust air must be expected, which, for example, is aggressive towards one another the materials used in the heat exchanger. For example, the moist exhaust air can be corrosive and there is a risk that the heat exchanger 93 of the heat pump 90 will be attacked. This successfully prevents corrosion of the heat exchanger 93 of the heat pump 90, which under certain conditions can release the heat transfer medium contained in the circuit 99. This is particularly advantageous if the heat pump 90 is filled with special heat transfer media, which can be harmful to the environment in the event of an exit from the circuit 99 and/or pose a risk of explosion. Further advantageously, the heat transfer medium intermediate circuit 86, 86 'can be designed such that the intermediate circuit has a sufficiently high heat capacity or heat storage, similar to the integrated steam storage 54. An intermediate circuit dimensioned in this way can be used in the event of an unplanned or planned shutdown of the machine, for example in In the event of a demolition, the departing heat source or exhaust air 84 can be briefly compensated for with sufficient thermal energy. This advantageously enables short-term continued operation of the components included and advantageously prevents damage caused by excessively high temperature gradients of the heat pump.

At the same time, the heat pump 90 receives the heating medium to be heated through the condensate return line 58 at a temperature T_58 via the heating medium supply line 97 supplied. By simultaneously supplying electrical energy 80, the heating medium is heated by the heat pump 90 to a higher temperature level T_58 'in the heating medium discharge line 91 and the return of the separate heat transfer medium intermediate circuit 86' is cooled to a lower temperature T_86'.

The heated heating medium 58', preferably the condensate, is provided to the steam and condensate system 5 at a set temperature level T_58' of greater than or equal to 100°C, preferably greater than or equal to 110°C, and less than or equal to 130°C, preferably less than or equal to 120°C .

The heat pump 90 is suitable for increasing a temperature of a condensate in the condensate return line 58 by a temperature difference of greater than or equal to 40°K, preferably greater than or equal to 60°K.

Advantageously, the heat pump 90 is suitable for generating heat energy at a temperature T_84 in the exhaust air line 84, 84' of greater than or equal to 55°C, preferably greater than or equal to 60°C, and less than or equal to 80°, preferably less than or equal to 70°C. particularly energy efficient to recover

1 c shows an alternative arrangement of the arrangement shown in FIG.

The further downstream heat exchanger 63 supplies a further, third secondary consumer system 72 with the exhaust air 84" from the previous heat exchanger 61 and uses a further part of the residual heat still contained in the exhaust air 84".

Furthermore, in Figure 1 c, the further mobile steam generator 56 in the low-pressure region 52 is arranged upstream of the steam compressors 55 and the steam generator 53, which is preferably passive or electrically heated, is arranged essentially directly downstream of the heat pump 90. Figure 1 d shows an alternative arrangement to the arrangement shown in Figure 1 b, wherein the heat pump 90 within the thermal energy recovery system 6 marked with a dashed box is followed by a further heat exchanger 63, which is advantageously designed as an air-air heat exchanger 63.

The further downstream heat exchanger 63 supplies the drying hood supply air heating 82, which is also a secondary consumer system, with the exhaust air 84 'of the previous heat exchanger 61 and uses a further part of the residual heat still contained in the exhaust air 84'.

Furthermore, in Figure 1 d, the further mobile steam generator 56 is arranged downstream of the steam compressors 55 in the high-pressure area 51 and the, preferably passive or electrically heated, steam generator 53 is arranged essentially directly downstream of the heat pump 90.

Furthermore, in Figure 1 d, the heat exchanger 61 upstream of the heat pump 90 is supplied directly with the exhaust air 84 with a separate heat transfer medium intermediate circuit 86.

The exhaust air 84" leaving the downstream heat exchanger 63 now has a lower temperature T_84" than the temperature T_84' of the incoming exhaust air 84' or is discharged into the environment 88.

In an alternative embodiment, not shown, the exhaust air line 84 from the machine 1 can be fed directly to the heat pump 90 with a usual temperature of greater than or equal to 75 ° C to 90 ° C. The supplied exhaust air stream 84 is supplied to the heat pump 90 or the first heat exchanger 93 of the heat pump 90 via the heat source supply line 92 and a first part of the residual heat contained in the exhaust air 84 is further used. There is no further heat exchanger 60 connected upstream of the heat pump 90.

Figures 3a to 3e show further alternative arrangements of at least one heat pump 90 in the machine 1. The heat pump 90 is advantageously included in the heat energy recovery system 6 of the machine 1, which is marked with a dashed box. The heat energy Recovery systems 6 of the machine 1 are advantageously also used for the energy-efficient supply of required heat in other secondary system consumers 70, 71, 72, 73, 74.

Figure 3a shows an arrangement of a heat pump 90, which is downstream of a first heat exchanger 60. The exhaust air flow 84 "is subsequently passed through a second heat exchanger 61, followed by a further heat pump 90 and a third heat exchanger 62 for energy-efficient heat energy recovery and the possibility of increasing the heat energy to a slightly higher temperature level that may be required. Advantageously, the set temperature differences in a second heat pump are in the range of dT = 15°K.

The first heat exchanger 60 further heats, for example, the supply air 82 for the drying hoods 29, 39, 49 of a drying section 2, 4 from the environment 88. The first heat pump 90 supplies the steam and condensate system 5, the second heat exchanger 61 supplies a first secondary system consumer circuit 70, the second heat pump 90 has a second, further secondary system consumer circuit 71, and the third heat exchanger 62 has a third, further secondary system consumer circuit 72. What is crucial for such a multi-stage arrangement is that the temperature levels required to supply the secondary system consumer circuits 70, 71, 72 are further reduced or . are reduced and as much of the thermal energy contained in the exhaust air 84 is recovered and the temperature T_84 is cooled down approximately to ambient temperature T_88. It is crucial to design the separate heat exchangers 60, 61, 62, 63, 64 used or the heat exchangers 93 included in the heat pump 90 in such a way that they have large heat exchanger transfer surfaces for the efficient exchange of heat energy to heat the greatest possible recovered heat energy with a low energy requirement 80 of the heat pump 90 to the required temperature level or heat level.

At the same time, a maximum heat exchanger transfer area is limited from aspects such as production and costs. As secondary system consumers 70, 71, 72, 73, 74 with reduced or low temperature levels, for example, the drying hood supply air 82, the process water heating, the hall ventilation or hall heating and the supply of steam blowing boxes in the drying sections can be connected.

For the secondary system consumers, after adjusting the heat exchanger transfer surfaces in the heat pump 90 or the separate heat exchangers 60, 61, 62, 63, 64 when the machine 1 is operating, there is a lower, so-called temperature spread, which is via the temperature difference in the heat pump 90 from the Temperature in the heat exchanger 93 or the evaporator 93 and the temperature in the heat exchanger 95 or the evaporator 95 can be determined. The temperature difference usually used, for example for hall ventilation or hall heating, on the heating medium side of the heat exchanger is between greater than or equal to 18°K to less than or equal to 22°K, preferably 20°K. This means that the usual high inlet and return temperatures of 25°C to 50°C can be achieved. To achieve the usual hall temperature of 20°C to 25°C, the modified heat exchangers on the heating medium side only have reduced inlet and return temperatures of 20°C to 40°C and a temperature difference greater than or equal to 13°K to less than or equal to 18° K, preferably operated at essentially 15°K.

A heat deficit that is still present in a subsequent secondary system consumer 72, 73, 74, for example in the heating water or process water system, but also at other points in the paper manufacturing process with a heat requirement at a temperature level of up to 60 ° C, can be compensated for by a second, downstream heat pump 90, whereby this The second heat pump then works again with a small temperature difference and therefore very efficiently.

Figure 3b only shows the area of the thermal energy recovery system 6 and the corresponding supply lines and discharge lines, which are included in the machine 1, as shown in Figure 1a or 3a. 3b also shows an arrangement in which the exhaust air stream 84 is led directly into a heat pump 90, for example to supply the drying hood supply air 82. There are then two heat pumps 90 further heat exchangers 60, 61 for heat energy recovery with associated secondary consumption 70, 71 are arranged downstream.

Advantageously, a heat pump 90 works more efficiently, the smaller the temperature swing or the temperature difference to be achieved. An arrangement of the first heat exchanger 93 or the evaporator 93 of a heat pump 90 as a first stage for heat recovery in an exhaust air line 84 is therefore particularly advantageous.

3c shows an alternative arrangement of the arrangement shown in FIG. 73 supplied. It is characteristic that the downstream secondary system consumers are further reduced in temperature.

3d shows an alternative arrangement of the arrangement shown in FIG. Analogous to Figures 1c and 1d, this results in the advantages explained. The exhaust air stream 84 is conducted via a first heat exchanger 60, for example to supply the drying hood supply air 82. The exhaust air stream 84 'is conducted in a subsequent further heat exchanger 61, preferably an air heat transfer medium heat diverter 61. The further heat exchanger 61 exchanges the heat via a separate heat transfer medium intermediate circuit 86 with a downstream heat pump 90. The further heat exchanger 61 can be followed by a further heat exchanger 62 in the exhaust air line 84" to supply a secondary system consumer 72 before the exhaust air 84" has reached an ambient temperature 88. In a parallel heat energy recovery system 6, a secondary system consumer 70 is efficiently increased to a required temperature by the heat pump 90. It is also conceivable to connect several, preferably two, heat pumps 90 shown in series, one after the other, to supply further secondary system consumers 70, 71, or there is also one with a heat pump bypass line 89 If demand increases, the second heat pump 90 can be switched on. Combination can be achieved.

3e shows an arrangement in which the exhaust air stream 84 is guided via a first heat exchanger 60, preferably an air heat transfer medium heat exchanger 60. The heat exchanger 60 exchanges the heat via a separate heat transfer medium intermediate circuit 86 with a downstream, first heat pump 90 out of. This first heat pump 90 heats fresh air from the environment 88 of the machine 1 and is supplied as heated drying hood supply air 82 to the drying hoods 29, 39, 49 of the drying section 2, 4. Due to a small temperature difference, this first heat pump 90 works particularly efficiently. The heat exchanger 60 can be followed by a further heat exchanger 61 in the exhaust air line 84 'for supplying, for example, the steam and condensate system 5 via a further, second heat pump 90 and a separate intermediate heat transfer medium circuit 86, since the exhaust air 84'' is still corrosive compared to the materials in the heat exchanger.

Further heat can be removed from the exhaust air 84" by a further heat exchanger 62, which in this arrangement can be used to supply a secondary system consumer 70.

Before the exhaust air 84 has reached an ambient temperature 88, a further, third heat pump 90 is arranged directly in the exhaust air stream 84'", which removes the remaining heat from the exhaust air 84'" and is brought to a usable temperature level by the third heat pump 90 additional secondary system consumers 71 are heated particularly efficiently.

The supply or withdrawal of thermal energy into or from a “line” means that the medium moving in the line with a temperature and a mass and volume flow, for example air, water, preferably steam and/or condensate or a special heat transfer medium releases or absorbs heat energy. The “optimal COP” of a heat pump means that the heat pump is operated at the most efficient operating point with the highest efficiency for the requested or required temperature difference dT and can therefore provide a multiple of thermal energy from the additional, usually electrical, energy. The optimal COP increases with a smaller requested temperature difference. For example, with a temperature difference of dT=60°K, theoretically approximately COP values of 3 can be implemented, for example, with a temperature difference of dT=15°K, theoretically approximately COP values of 10 can be implemented. The temperature difference between the first heat exchanger and the second heat exchanger of the heat pump measured. In order to achieve the most energy-efficient operation possible, it is advantageous to arrange the heat pump as early as possible to recover condensation heat in the exhaust air flow.

A “cold start” of a machine means that all possible storage devices have been used up and the temperature of the machine and included components is essentially the same as the ambient temperature. This is usually the case after a long shutdown, such as a modernization or conversion.

A “warm start” of a machine means that there is still enough heat stored in the machine and the machine is restarted from a standstill. This is usually the case after a short stoppage, such as a small error such as a web break or a short maintenance.

“Heat source” is understood to mean a media stream or a heat transfer medium stream, preferably an exhaust air stream 84 and/or water stream 86, with residual heat from a machine section 2, 3, 4 of the machine 1, the residual heat from the “heat source” is used.

A “heat sink” or a “heat consumer” is a medium stream or a heating medium stream, preferably a supply air stream 82 and/or water, steam and condensate stream 57, 58, preferably for a heat consumer such as a steam Condensate system 5 or a so-called secondary system consumer 70, 71, 72, 73, 74, for example a drying hood supply air heating 82, with heat being supplied to the heat sink.

The “dew point” temperature is the temperature in a medium, preferably a heat transfer medium, in particular a moist exhaust air 84, 84 ', 84", from which the condensation of the gaseous component contained, preferably the moisture, takes place. The dew point is characterized by the fact that the vapor saturation pressure is equal to the vapor partial pressure of the medium.

Reference symbol list

1 machine

2 drying section

21 dry section

22 dry section

23 dry section

29 drying hood

291 drying hood of a drying section

3 more machine parts

31 vacuum blowers in a forming section

4 Drying section

41 dry section

49 drying hood

5 Steam and condensate system

50 steam distributors

51 high pressure area

52 Low pressure range

53 steam generators

54 steam tanks

55 steam compressor

56 additional steam generators

57 steam supply line

58 condensate return line

58' condensate return line with increased temperature compared to 58

59 Mixing line high-pressure-low-pressure area

6 thermal energy recovery system

60 heat exchangers

61 additional heat exchangers

62 additional heat exchangers

63 additional heat exchangers

70 secondary system consumers 71 additional secondary system consumers

72 additional secondary system consumers

73 additional secondary system consumers

74 additional secondary system consumers

80 electrical energy supply

82 Supply air line drying hood, supply air flow

84 Exhaust air line for drying hood, exhaust air flow

84' low temperature exhaust duct compared to 84 (T_84>=T84'>=T84")

84" low temperature exhaust duct compared to 84' (T_84>=T84'>=T84")

85 non-fossil fuel supply, preferably hydrogen supply

86 Separate heat transfer medium intermediate circuit, preferably water

86' heat transfer medium intermediate circuit with higher temperature T_86' than T_86

88 Ambient, Ambient Line, Ambient Temperature, Ambient Pressure

89 By-pass return line, further heat exchanger intermediate circuit

90 heat pump

91 Heating medium drain, preferably water or condensate

92 heat source supply line

93 heat exchangers, evaporators

94 compressor

95 heat exchanger, condenser

96 relaxation organ

97 Heating medium supply line, preferably water or condensate

98 heat source dissipation

99 circuit

F fibrous web

T temperature

MD machine direction

CD machine cross direction x, y, z coordinates

Claims

Patent claims 1. Machine (1) for producing or treating a fibrous web (F), in particular a paper, cardboard or tissue web (F), comprising at least one drying section (2, 4) and at least one steam and condensate system (5) and at least a heat energy recovery system (6), and wherein the at least one drying section (2, 4) comprises at least one exhaust air line (84) and at least one drying section (21, 22, 23, 41), and wherein the steam and condensate system ( 5) comprises at least one steam supply line (57) and at least one condensate return line (58), and wherein the thermal energy recovery system (6) comprises at least one heat pump (90), and wherein the at least one drying section (21, 22, 23 , 41) can be connected to the steam and condensate system (5) through the steam supply line (57) and the condensate return line (58) and can be supplied essentially completely or partially with steam, and wherein the at least one drying section (2 , 4) and the at least one steam and condensate system (5) are in an operative connection via the at least one heat energy recovery system (6), such that the heat pump (90) is exposed to an exhaust air flow from the at least one exhaust air line (84, 84 ', 84") partially removes residual heat energy and supplies heat energy to a condensate of at least one condensate return line (58) with an additional supply of electrical energy (80), characterized in that the at least one heat pump (90) in the exhaust air Line (84) is arranged in such a way that the heat pump (90) recovers the remaining heat energy in the exhaust air line (84, 84 ', 84") before reaching a dew point temperature of the exhaust air flow and that the steam and condensate system (5) comprises a steam accumulator (54) arranged downstream of the heat pump (90) for storing the steam. Machine (1) according to claim 1, characterized in that the heat pump (90) is preceded by at least one further heat exchanger (60) in the exhaust air line (84), preferably an air-air heat exchanger (60) or an air-heat transfer medium heat exchanger (60). Machine (1) according to claim 1 or 2, characterized in that the heat pump (90) is preceded by a further heat exchanger (61) in the exhaust air line (84), preferably an air heat transfer medium heat exchanger (61), in particular an air Water heat exchanger (61), such that the heat pump (90) recovers the heat from a separate heat transfer medium intermediate circuit (86, 86 '). Machine (1) according to one of the preceding claims, characterized in that the heat pump (90) is arranged such that thermal energy at a temperature, preferably dew point temperature, of the exhaust air flow in the exhaust air line (84, 84 ', 84 “) of greater than or equal to 45°C, preferably greater than or equal to 60°C, and less than or equal to 80°, preferably less than or equal to 70°C. Machine (1) according to one of the preceding claims, characterized in that the heat pump (90) is designed such that a steam requirement required in normal operation of the machine (1), preferably a steam temperature and a steam mass flow, in the steam and Condensate system (5) is provided solely by the heat pump (90). Machine (1) according to one of claims 1 to 4, characterized in that the heat pump (90) is followed by a steam generator (53) included in the steam and condensate system (5), preferably a passively functioning or electrically operated steam generator (53), which is designed in this way to convert condensate (58) heated to steam temperature by the heat pump (90) into steam. 7. Machine (1) according to one of the preceding claims, characterized in that the steam storage (54) comprises an electrical heating device (80) or a hydrogen burner heating device (85) for maintaining a steam temperature. 8. Machine (1) according to one of the preceding claims, characterized in that the steam storage (54) is designed such that the steam storage (54) has a storage period of the steam of greater than or equal to 8 hours, preferably greater than or equal to 12 hours, in particular greater equal to 72 hours, to supply the required amount of steam when the machine is warmly started (1). 9. Machine (1) according to one of the preceding claims, characterized in that the steam accumulator (54) is designed such that the steam accumulator (54) produces steam at a steam temperature of greater than or equal to 110 ° C and a steam pressure level of greater than or equal to 0.4 and less than or equal to 1.5 bar above atmospheric pressure. 10. Machine (1) according to one of the preceding claims, characterized in that the steam and condensate system (5) comprises at least one electrically operated steam compressor (55), preferably two, three or four series-connected and electrically operated steam compressors pressors (55), designed in such a way that a steam in the steam supply line (57) is increased to a steam pressure level of greater than or equal to 5, preferably greater than or equal to 6 and less than or equal to 12, preferably less than or equal to 10, bar above atmospheric pressure. 11. Machine (1) according to one of the preceding claims, characterized in that the steam and condensate system (5) comprises a further steam generator (56), preferably a mobile steam generator (56), which is designed such that a short-term for the duration of a cold start The steam required by the machine (1), preferably a steam temperature and a steam mass flow, is provided in the steam and condensate system (5) only until an operating temperature for normal operation of the machine (1) is reached. 12. Machine (1) according to one of the preceding claims, characterized in that the exhaust air line (84) with a drying hood (29, 291, 49), a drying section (2, 4), a drying hood (29, 291, 49) a Yankee drying cylinder, a drying hood (291) of a contactless drying section (21, 22, 23, 41), a vacuum blower of a drying section (21, 22, 23, 41) and/or a vacuum blower of a forming section (31). 13. A method for producing or treating a fibrous web (F), in particular a paper, cardboard or tissue web (F), in a machine (1) according to claim 1, characterized in that the heat pump (90) before reaching a dew point Temperature of the exhaust air stream in the exhaust air line (84, 84 ', 84") recovers the remaining heat energy and that a steam is stored in a steam storage (54) downstream of the heat pump (90) and that a set steam requirement of the steam - and condensate system (5) a) during normal operation of the machine (1) is provided solely by the heat pump (90), and b) during a warm start of the machine (1) solely by the steam storage (54) in the steam and condensate system ( 5) is provided. Method according to claim 13, characterized in that in addition c) during a cold start of the machine (1), a further steam generator (56), preferably a mobile further steam generator (56), is arranged in the steam and condensate system (5) in such a way that The additional steam generator (56) provides the required steam until normal operation of the machine (1) alone and/or in addition to the heat pump (90). Machine (1) for producing or treating a fibrous web (F), in particular a paper, cardboard or tissue web (F), comprising at least one machine section (2, 3, 4), preferably a drying section (2, 4) or forming section ( 3), and at least one thermal energy consumer, preferably a steam and condensate system (5) and/or a secondary system consumer (70, 71, 72, 73, 74, 82), and at least one thermal energy recovery system (6), and where which comprises at least one machine section (2, 3, 4) of at least one exhaust air line (84), and wherein the heat energy recovery system (6) is arranged in the at least one exhaust air line (84) and comprises at least one heat pump (90). , and wherein the at least one machine section (2, 3, 4) and the at least one heat energy consumer are in an operative connection via the at least one heat energy recovery system (6), such that the heat pump (90) is exposed to an exhaust air stream at least one exhaust air line (84, 84', 84") partially removes residual heat energy and with additional supply of electrical energy (80) to a heating medium flow of the one heat energy consumer (5, 70, 71, 72, 73, 74 , 82) supplies thermal energy, characterized in that the at least one heat pump (90) is arranged in the exhaust air line (84, 84', 84") in such a way that the heat pump (90) switches off before a dew point temperature of the exhaust air flow in the exhaust air line (84, 84 ', 84") recovers the remaining heat energy.