JPS60111092A - Cooling method of compressed gas in gas compressor plant equipped with power recovering apparatus - Google Patents

Abstract

PURPOSE:To permit the sufficient cooling for compressed gas by mixing the second coolant having a different temperature with the first coolant and allowing the second coolant to circulate in a heat exchanger in a condenser, thus reducing the loss of energy outside and recovering the more revolution power. CONSTITUTION:In a condenser 5, the second coolant is molten, and the concenttration is increased, and the first coolant into which the second coolant is dissolved is supplied into a heat exchanger 3 by a pump 6. Therefore, the second coolant circulates in a closed circuit, repeating vaporization and absorption. The second coolant works in a turbine 4 and recovers the heat of the gas compressed by a compressor 2. In this case, the property of the second coolant can be selected, with respect to that of the first coolant, to have the liquefaction temperature far lower than the temperature T8 of the outside cooling water, in the state under the outlet pressure of the turbine 4. Therefore, the temperature T10 of the gas in a discharge pipe 7 can be reduced far lower in comparison with the temperature T8 of the outside cooling water, and the driving power necessary for a high-pressure compressor 22 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention generally relates to a method for cooling compressed gas in a gas compression plant used in a chemical plant or the like.

(Prior art) In a plant that aims to reduce power consumption by recovering compression heat generated in a compressor into power and using this power in the compressor, for example, it is possible to reduce the discharge temperature of compressed gas in the compressor. , means for recovering the amount of heat as rotational energy is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 52-3
7 (Described in '+ No. 46. This publicly known material describes a turbine cycle in which the heat of compressed gas discharged from a pressure III compressor is absorbed into an organic medium, and the organic medium is used as a working fluid. The gist of this document is to drive a turbine by means of a compressor, and to connect the turbine to a single-distribution compressor and use the compressor to drive the compressor. It is considered that the compressor shown in Fig. 2 includes one compressor and the third one.
Model 1 I has two compressors, and the system diagram shown in Figure 3 is the same as the drawing in the above-mentioned publication. compressor 2 or 21,
22 is driven by the driver 1, and the compressor 2 or 21.
The compressed gas discharged from 22 is transferred to heat exchanger 3 or 31.
．． 32, and further lowered to a normal operating temperature via a cooler 8 or 8, 9, and then discharged through a discharge pipe 7.

(Problems to be Solved by the Invention) In the above-mentioned known plant, a large amount of water is used in the coolers 8 and 9, and a large amount of jH% obtained from the compressed gas is released outside the system.
There is a problem that the amount of heat is lost, and as a result, the amount of heat obtained by the turbine is small, and the amount of energy recovered as rotational power is small.

The present invention was made in view of the above, and it reduces the loss of energy to the outside and recovers a large amount of rotational power, and also allows compressed gas on the discharge side of the compressor to pass through a heat exchanger in the system. Therefore, it was engineered to be sufficiently cooled to the temperature at which compressed gas is commonly used.

(Means for Solving the Problems) The present invention cools the IF condensed gas by installing a heat exchanger at the outlet of the compressor, and circulates the refrigerant in the heat exchanger through the turbine cycle to absorb the thermal energy of the compressed gas. In plan 1 for converting into rotary power, two types of refrigerants with different vaporization temperatures are mixed and used, the compressed gas at the outlet of the compressor is cooled by a heat exchanger, and the refrigerant in the mixed refrigerant is The second refrigerant in the first refrigerant is vaporized, a turbine is rotated by the second refrigerant, and the second refrigerant expanded and cooled by the turbine is sent to the second heat exchanger (7) to re-cool the compressed gas. 711, and then mixes the second refrigerant with the first refrigerant in the condenser to produce niJ
This is a method for cooling compressed gas in a gas IE compressor plant equipped with a power recovery device that includes a heat exchanger.

(Function) In FIG. 1, the heat of the gas compressed by the compressor 2 is transferred to the liquid first refrigerant through the heat exchanger 3L. The first refrigerant that has received this amount causes the second refrigerant that has dissolved therein to be emitted. The temperature of the second refrigerant, which has become gaseous, is lowered by cooling water supplied from the outside by the cooler 10. The second refrigerant then enters the turbine 4 and expands, causing the turbine to produce mechanical output, and the temperature of the second refrigerant itself becomes extremely low due to the expansion. The second refrigerant leaving the turbine 4 further cools the compressed gas leaving the previous heat exchanger 3 in the second heat exchanger 3' to a temperature of T1c+. Then, the second refrigerant leaving the second heat exchanger 3' heads to the condenser 5.

By the way, the condenser 5 is configured such that the first refrigerant whose concentration has been reduced by evaporating the second refrigerant in the heat exchanger 3 flows into the condenser 5. In some cases, it is cooled by external cooling water. The first refrigerant, whose temperature has been lowered by being cooled by the condenser 5, easily absorbs the gaseous second refrigerant coming out of the second heat exchanger 3'. It is advisable to select a second refrigerant whose degree of decomposition by the first refrigerant differs significantly depending on the temperature.

The second gaseous refrigerant is absorbed by the first refrigerant in the condenser 5 and becomes dissolved in the first refrigerant, that is, becomes a liquid incorporated in the first refrigerant. In other words, the condenser 9°5 converts the gaseous second refrigerant into a liquid state. The first refrigerant, which has a higher concentration by dissolving the second refrigerant, is sent back to the heat exchanger 3 by the pump 6. In this way, the second refrigerant circulates in the closed circuit while repeating evaporation and absorption. Then, the C turbine 4 performs work and can recover the heat of the gas compressed by the compressor 2.In addition, in this case, the properties of the second refrigerant are significantly different from those of the first refrigerant depending on the temperature. In addition to changing the degree of melting, the external cooling water 61 can be selected to have a much lower liquefaction temperature at the exit pressure of the turbine 4 than the degree TFI. It is possible to make the temperature T, o lower than the temperature T9 of the external cooling water.In that case, the cooling water 5i: #'; The amount of external cooling water required for H1, for example λ, is greater than in the case of the system shown in Fig. 2. However, the embodiment of the present invention shown in Fig. 1, for example, This is particularly effective in cases such as those in which the temperature T7 of the refrigerant circulating in the heat exchanger 3 can be lowered than the temperature of the cooling water in the (The driving power required for the compressor is proportional to the absolute temperature of the compressed gas at the compressor inlet. This also means that an intercooler is installed in the compressor equipment. ) As detailed above, when the embodiment of the present invention is implemented in a compressor equipment having an intercooler as shown in Fig. 3, the power is recovered in the turbine 4 and the driving power required for the high-pressure compressor is further reduced. (drive+jl!, the capacity of l can be significantly reduced.

Note that the cooler 10 is at the inlet of the turbine 4.

By lowering the degree T4, the turbine output is 1"? 2! It is intended to lower the degree of 16, and in the end the required level is 1.
This is designed to further lower the pipe gas temperature T7°. Of course, if the temperature of T10 does not need to be so low, the cooler 10 may be omitted.

In addition, a throttle device 11 is installed in the pipe where the first refrigerant goes from the heat exchanger 3 to the condenser 5.
It is better to adjust the

(Effects of the Invention) As is clear from the above explanation, the present invention cools the compressed gas produced by the gas compressor using a heat exchanger, and converts the heat obtained by the refrigerant into driving force in the blank 1-. Is the exchanger effective? f', lowering the temperature of the compressed gas to the yarn temperature, and converting the heat into power7 to minimize the loss of heat to the outside, so the power obtained can be used to drive the compressor. Since it can be added to the -H41H of power or used as another power engine to recover energy, it can be used with J Hakushu for compressor plans 1~ of chemical bran I, Tsu J Nagi plant, etc., and has an extremely large effect. It is something.

Also, depending on the conditions of use of the refrigerant, is it external? 47 j;++ It is also possible to make the compressed gas have a liquefaction level of 6 rA degrees at a turbine outlet pressure lower than the water temperature, so the compressed gas can be cooled to a low temperature. If this method is used in an intermediate heat exchanger, the rotational power of the high-pressure compressor can be reduced.Secondly, it also has the advantage of expanding the range of use of compressed gas.

[Brief explanation of the drawing]

FIG. 1 is a diagrammatic system diagram of one embodiment for explaining the present invention, and FIGS. 2 and 3 are diagrammatic system diagrams showing known examples, respectively. 1...Driver, 2.2], 22...Compressor, 3
, 3]. 32... Heat exchanger, 3'... Second heat exchanger, 4...
・Turbine, 5... Capacitor, 6... Pump, 7
...Discharge pipe, 8.9.10...Cooler.

Claims (1)

[Claims] In a plant that installs a heat exchanger at the outlet of the compressor to cool the compressed gas, and circulates the refrigerant in the heat exchanger to the turbine cycle to convert the thermal energy of the compressed gas into rotational power, two types of refrigerants with different vaporization temperatures are used. The compressed gas at the outlet of the compressor is cooled by a heat exchanger, the second refrigerant in the first refrigerant in the mixed refrigerant is vaporized, a turbine is rotated by the second refrigerant, and the turbine is rotated by the second refrigerant. The second refrigerant expanded and cooled by the second refrigerant is sent to the second heat exchanger to re-cool the compressed gas, and after cooling, the second refrigerant is mixed with the first refrigerant in the condenser and circulated to the heat exchanger. A compressed gas cooling method for a gas compressor plan 1 equipped with a power recovery device as described above.