DE102009016775A1 - Method and device for generating water vapor at a high temperature level - Google Patents

Abstract

In the present invention is a heat recovery system, which in contrast to the invention according to DE 10 2008 027 825.4 is a three-stage process, wherein in the first stage instead of an evaporator, a recuperator can be used and the second temperature level as subcritical or transcritical process. In addition, higher flow temperatures are possible, so that higher-temperature heat sources can be used. The invention extends the field of application of the method and the arrangement for generating water vapor according to DE 10 2008 027 825.4.

Description

The invention relates to an addition to the patent application DE 10 2008 027 825.4 "Method and arrangement for generating water vapor".

In The industry generates process waste heat that is generated in usually unused via recooling systems discharged to the environment or introduced into surface waters becomes.

These Waste heat contains valuable primary energy in transformed form; the operation of recooling systems causes costs. On the other hand, however, there is an industrial one Heat demand generated by heat generators must be covered. It makes economic sense, heat recovery systems use; These have in addition to the economic effects in addition to the Benefit to reduce the environmental impact. The according to the state of Technik known heat pump systems are for basically suitable, but cover the temperature ranges on both the heat source and the heat sink side only insufficient.

Of the Invention is therefore the object of a method and a provide appropriate heat recovery system, which significantly extend the two temperature ranges.

The The object is achieved by the features of claims 1 and 5 solved; advantageous Embodiments are defined by the dependent claims disclosed.

The The solution according to the invention is therefore a Method in which a three-stage heat recovery system, consisting of a first temperature level for raising the waste heat temperature a level that allows it in a second temperature level with a high pressure side sub- or transcritical heat pump to reach a temperature level at which water in a third Vaporizes at atmospheric or higher pressure, is used. The water vapor is in the third temperature stage by one or more one-stage or multistage vapor compressors raised to an industrially usable temperature level.

The Heat recovery plant for the production of water vapor consists of a first temperature stage, which serves as a heat pump executed with preferably natural refrigerant is a second temperature stage as a sub- or trans-critical left-hand process and a third stage with one or more multi-stage vapor compressors or with one or more single-stage vapor compressors connected in series. This offers the heat recovery system especially for heat consumers with high process temperatures at.

The first temperature level can be considered completely subcritical operated refrigerant circuit can be performed. However, if the waste heat to be used falls to one sufficient temperature level is sufficient in their place the installation of a recuperator. Furthermore, there is the possibility the first temperature stage as combined heat and power plant or fuel cell perform that for the second temperature level completely or partially electrical drive energy and provides waste heat as a heat source. In addition, can the first temperature level alternatively as a gas engine, the for the second temperature stage completely or partially mechanical drive energy and waste heat as a heat source supplies formed be. In the temperature levels one to three electrical and internal combustion engine drives for the compressors be used. Only when using a gas engine is the first Temperature level on a sub- or trans-critical internal combustion engine driven heat pump limited. "

The Execution of the second temperature stage takes place as sub- or transcritical process with high pressure control without additional Refrigerant storage, preferably with the natural Refrigerant ammonia, with the permissible compression end temperature by cooling the injected refrigerator oil is limited to the permissible value.

If necessary, becomes an over- or subcritical heat extraction made in the second temperature level between 0 and 100%, thereby minimizing the exergetic losses at transcritical Heat extraction for preheating processes is possible.

Becomes in the first and second stages of the heat recovery system the same type of refrigerant used, the evaporator condenser between first and second stage without dividing walls as medium pressure bottle be executed.

The First stage compressors are positive displacement machines (preferably Reciprocating, screw or scroll compressors), the compressors of second stage are displacement machines (preferably reciprocating, Screw, scroll or liquid piston compressors preferably with ammonia as refrigerant and an insoluble oil as piston liquid and the third stage compressors are displacement or flow machines (preferably screw compressors, Turbo-compressor or radial fan).

To improve the coefficient of performance and to limit the compression end temperature can one-, two- or higher-stage vapor compressor with Intermediate cooling can be used by condensate injection. To increase the pressure, the use of steam compressors is provided.

When Heat sources become industrial waste heat streams high temperature, returns in district heating or geothermal networks. Furthermore, it is provided for the drive of the compressor energy from renewable sources too use.

The Invention will be described below with reference to an embodiment explained in more detail; For this purpose, the figure shows a plant scheme the inventive arrangement.

The system diagram shown shows the evaporator in the first temperature stage 1 one with a natural refrigerant, here ammonia, operated heat pump. The evaporator absorbs the heat flow from a process cooling water circuit and vaporizes the liquid refrigerant. The now vaporous refrigerant is from the compressor 2 condensed to the condensing pressure of the first temperature stage. In the evaporator condenser 3 the refrigerant is liquefied with heat release and then into the refrigerant collector 4 initiated. The refrigerant collector 4 has the task, the operating point-dependent refrigerant charge in the evaporator 1 and in the evaporator condenser 3 compensate. About the expansion valve 5 the refrigerant is returned to the evaporator 1 fed.

In the evaporator condenser 3 the natural refrigerant ammonia of the second temperature stage is evaporated at a minimum temperature. The compressor 6 the vaporized refrigerant compresses to a supercritical pressure of 120 bar. Subsequently, the compressed supercritical refrigerant in the heat exchanger 7 where it gives off heat without being liquefied. This is ensured by the fact that the control valve 8th just enough refrigerant back into the evaporator condenser 3 relaxes that pressure in the heat exchanger 7 is maintained at the predetermined setpoint. As the evaporator capacitor 3 on the side of the second temperature level is flooded by this measure, can be installed on a suction side or the heat exchanger 7 downstream refrigerant collector can be omitted. Part of the heat exchanger 7 Refrigerated refrigerant is released through the valve 11 supplied to the oil cooler.

Because of the use of a screw compressor as a compressor 6 is between this and the heat exchanger 7 an oil separator interposed. This in the oil separator 9 collected oil is then the oil cooler 10 fed. In the oil cooler, it is due to refrigerant, which previously in the heat exchanger 7 cooled down and through the valve 11 was relaxed, cooled and returned to the compressor 6 fed. That of the valve 11 Released refrigerant, after passing through the oil cooler, is sent to the compressor on the suction side or, if present, an economizer connection on the compressor 6 fed.

In the third stage is in the heat exchanger 7 Water evaporates, passing through the compressor 12 and 13 is compressed to the required pressure level. Between the two compressors takes place by condensate injection by means of the valve 14 an intercooling of water vapor.

in the Embodiment is the evaporation temperature of the Refrigerant ammonia of the first temperature level at 40 ° C and the liquefaction temperature at 75 ° C, wherein the associated pressures are 15.6 bar and 37.1 bar. Thus, a heat pump performance number of at least 5.2 reached.

In the second temperature level, the refrigerant is on a Pressure of 120 bar compressed. The compression end temperature can through the refrigerating machine oil to the permissible oil temperature be limited by 160 ° C. The figure of merit of the second Temperature level is 4.7. Produces water vapor at atmospheric pressure, this can be done by means of two series-connected steam compressors be compressed to about 1.4 bar saturated steam pressure.

1

Evaporator

2

compressor

3

evaporator condenser

4

Refrigerant collector

5

expansion valve

6

compressor

7

Heat exchanger

8th

control valve

9

oil separator

10

oil cooler

11

Valve

12

compressor

13

compressor

14

Valve

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102008027825 [0001]

Claims (8)

Process for the production of water vapor according to the main patent DE 10 2008 027 825.4 At a high temperature level, is used in the process waste heat, characterized in that a heat recovery system is used, with a first temperature level to increase the waste heat to a level that allows, in a second temperature stage with a high pressure side sub- or trans-critical heat pump to a temperature level reach, evaporates in the water at atmospheric or higher pressure and the water vapor in a third temperature stage by means of a single or multi-stage vapor compressor or more in series single-stage or multi-stage vapor compressor is raised to an industrially usable temperature level. Method according to claim 1, characterized in that that in the second temperature stage as the refrigerant ammonia is used. Method according to Claims 1 and 2, characterized that the permissible compression end temperature by injection is limited by cooled lubricant. Method according to claim 1, characterized in that that in the second temperature stage, a supercritical or subcritical Heat extraction takes place in a range of 0 ... 100%. Apparatus for carrying out the method according to claim 1, characterized in that it is a heat recovery system for heat consumers with high return temperatures, comprising three stages, wherein the first stage is an evaporator ( 1 ), a compressor ( 2 ), an evaporator condenser ( 3 ), a refrigerant collector ( 4 ) and an expansion valve ( 5 ), the second stage from the evaporator condenser ( 3 ), a compressor ( 6 ), an oil separator ( 9 ), a heat exchanger ( 7 ), a control valve ( 8th ), an oil cooler ( 10 ) and a valve ( 11 ) and the third from the heat exchanger ( 7 ), two compressors ( 12 and 13 ) and a valve ( 14 ) is constructed. Device according to claim 6, characterized in that that the first temperature stage as recuperator, combined heat and power plant, Gas engine or fuel cell is executed. Device according to claim 6, characterized in that the compressors ( 2 and 6 ) of the first and second stages are screw, scroll, turbo or liquid piston compressors. Device according to claim 6, characterized in that that the third-stage compressors screw compressors, turbo compressors or radial fans are.