DE2651888A1 - Steam turbine waste heat recovery circuit - has part of heat exchange medium passed through condenser driven by turbine - Google Patents

Abstract

Waste heat from a steam turbine is sensed by employing a compressor (2) mounted on the drive shaft of the expansion turbine (1). This is connected to a circuit in which ammonia is circulated, with a pump (8) passing the ammonia through a heat exchanger (3) after the turbine. Between the pump and compressor is an evaporator (4). This is in parallel with a valve (9). Parallel to the flow from the comparator (4) to the compressor are two heat exchangers (6, 7) with a condenser (5) between. These heat exchangers are also connected to the turbine (1). Thus part of the evaporated ammonia gas is compressed then condensed while heat is extracted, expanded, then reunited with the main flow.

Description

LINDE AKTIEfeQSCCHAFT

(H 876)

Ke / vol 11.11 * 1976

Method and device for utilizing heat from a low-temperature heat carrier

The invention relates to a method and a device for Utilization of heat from a low-temperature heat transfer medium in which a circulating medium is created by exchanging heat with the heat transfer medium evaporated at a lower temperature, work performance relaxed, condensed by cooling and before its renewed evaporation higher pressure is pumped *

In thermisohen power plants, which generally operate with hot steam, still, the water leaving the turbines steam to a temperature of about 50 ^0C. This heat is mostly given off to the environment as waste heat, since economic utilization does not seem sensible because of the low temperature level.

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LINDE AKTIENGESELLSCHAFT

It is also a method of harnessing them Waste heat has become known «in which this waste heat is transferred from a turbine circuit that works with ammonia and is kept close to the main circuit of the power plant and is used to generate mechanical energy is used (ITT-OS 14 01 466).

In contrast, the invention is based on the object of specifying a method in which the thermal energy of a Heat transfer medium of lower temperature is used to generate heat of higher temperature.

This object is achieved according to the invention in a method of the type mentioned at the outset in that a first partial flow is branched off from the evaporated circulating medium, compressed, condensed by removing heat, expanded and with it the remaining second part of the circulating medium before it Evaporation is reunited.

Due to the process according to the invention, part of the heat of the low-temperature heat transfer medium is Process comparable to the principle of a heat pump is "promoted" to a higher temperature level and is consequently available as valuable useful heat, i.e. available at a high temperature. Another part of the heat is required for the evaporation and heating of the circulating medium and is devalued by the work-performing relaxation.

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LINDE AKTIENGESELLSCHAFT

It is particularly advantageous if the compressor for the first partial flow comes directly from the turbine for the work-performing one Relaxation of the second partial flow is driven, since in this case a system for carrying out the method without Supply of external energy can be operated.

According to a particularly advantageous development of the inventive concept, the compressed first partial flow of the Circulation medium through Wärmetausoh with the remaining evaporated second part of the circulatory medium immediately before and immediately chilled after the withdrawal of heat. This increases the efficiency of the entire procedure enlarged.

Particularly suitable circulation media are Ammonia and fluorinated hydrocarbons.

Suitable for carrying out the method according to the invention is a device with an evaporator, an expansion machine and a condenser having working circuit, in the case of the at the outlet line of the evaporator a branch line connected to the suction side of a compressor is provided and the output side of the compressor with a line that has at least one capacitor and a downstream throttle valve leads, with the inlet line of the evaporator is connected.

The drive shaft of the Verdiohters is advantageous connected to the output shaft of the expansion turbine either directly or via a transmission gear.

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LINDE AKTIENGESELLSCHAFT

The invention is illustrated below with the aid of an aohematisoh illustrated exemplary embodiment explained in more detail:

A system for performing the erfindunsgemäße The method consists of an expansion turbine 1, a compressor 2, heat exchangers 4 to 7, and a liquid pump 8 and a throttle valve 9

A circulating medium (ammonia) is evaporated at a pressure of 19 ata duroh in the heat exchanger 4 the supply of heat of a temperature level of about 50 ⁰ C. The ammonia vapor is facing the evaporator 4 at a temperature of 47 ⁰ C and is initially and then warmed in the heat exchangers 7 and 6 to 81 ⁰ C to 128 ⁰ C. It is then expanded to a pressure of approx. 6 ata while performing work in the turbine 1, during which it cools down to 81 ° C. In the heat exchanger 3 , it is then ^{cooled to approx. 8 °} C. by releasing heat to the surroundings, whereupon it liquefies. With the aid of the pump 8, the liquid ammonia is conveyed again to 19 ATA and (after mixing with a partial flow described below) is reintroduced into the heat exchanger 4 for evaporation.

According to the invention a first Teilstiom is branched off (in the example # 47) from the main circuit downstream of the evaporator at point 10 and compressed in the compressor 2, it woduroh SiOH to 131 ⁰ C heated. Part of the heat of the compressed circulating medium is transferred to the circulating medium of the heat exchanger 6

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LINDE AKTIENGESELLSCHAFT - Sr-

transmit the second sub-stream, "wherein the first Teilstroffl to about 84 ⁰ C abktlhlt. Duroh extraction of the useful heat in the heat exchanger 5, the ammonia of the substream is ^{cooled to 81 0} C and liquefied. After further cooling in heat exchanger 7 to about 62 ⁰ C the partial flow is depressurized in the throttle valve 9 and zugemisoht the main circuit again at the point. 11 The mixture resulting from the stream has a temperature of 54 ⁰ C.

For example, an amount of electricity of 1.89 kg / h for the main circuit and one for the sub-circuit Assuming 1 kg / h, the heat exchanger would have to be supplied with 4,750 kcal / h. 480 kcal would be dissipated at heat exchanger 3 * while the heat exchanger 5 270 koal / h useful heat are obtained can. . ·

The quantitative ratio of the first and the second partial flow depends on the temperature level of the heat transfer device and the environment. It can take any value between 0 and 1 - ν. The higher the heat carrier, the higher the value will be and the lower the temperature is. In the practical application range of the invention it will be between 0.1 and 0.9 »

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2 rs te

BATH ORIGINAL

Claims (1)

26b 1883 LINDE AKTiENGESELLSCHAFT ♦ -Each- (H 876) H 76/093 - Ke / vol II.II.I976 Sponsorship claims 1. Process for utilizing heat from a heat transfer medium lower temperature, at which a circulating medium through heat exchange with the heat transfer medium of lower temperature. evaporated, doing work expanded, condensed by cooling and pumped to a higher pressure before re-evaporation, characterized in that of the evaporated circulating medium a first partial flow is branched off, compressed, condensed by removing heat, expanded and with the remaining second Part of the circulating medium before it evaporates again is united. 2. The method according to claim 1, characterized in that the expansion of the circulating medium in an expansion machine occurs, duroh the compressor of the partial flow of the circulating medium is driven. . Process according to claim 1 or 2, characterized in that the compressed first partial flow of the circulating medium is cooled by heat exchange with the evaporated remaining second part of the circulating medium immediately before and immediately after the removal of heat. 80982Π / 0 34Ό LINDE AKTIENGESELLSCHAFT 4. The method according to any one of claims 1 to 3 < characterized in that ammonia and fluorinated hydrocarbons are used as the circulating medium be used. 5. Apparatus for performing the method according to claim 1 with • an evaporator, an expansion machine and a Working circuit having a capacitor, characterized in that that at the outlet line of the evaporator (4) a branch line connected to the suction side of a compressor (2) is provided and the output side of the Verdiohters, with a Line that leads via at least one capacitor (5) and a downstream throttle valve (9) to the inlet line of the evaporator (4) is connected. 6. Apparatus according to claim 5 *, characterized in that the drive shaft of the compressor (2) is connected to the output shaft of the expansion machine (1). 7 · Device according to claim 6, characterized in that the Connection takes place via a transmission gear. 809820/0340