JPH02146208A - Compound heat utilizing plant - Google Patents

Abstract

PURPOSE:To aim at improvement of thermal efficiency by utilizing condensed water from a condenser as a heat resource of an absorption refrigerating machine and cooling and condensing of discharged steam from a steam turbine by its returning water in a title plant comprising a power generation installation and an air-conditioning installation. CONSTITUTION:A recovery boiler 2 is installed at the exhaust gas line of a gas turbine 1, steam generated here is supplied to a steam turbine 3 to generate power to drive a generator 4. Steam from the steam turbine 3 is cooled and condensed at a condenser 5 and is returned to the recovery boiler 2 by a feed pump 6 as condensed water. A part of the condensed water is supplied to an absorption refrigerating machine 8b by a circulating pump 7, refrigerant in the machine is utilized as a heat resource for making cooling water which is used to make cooling medium in the machine to be evaporated and condensed. Condensed water from the refrigerating machine is recovered to the condenser 5. The refrigerating machine 8 is combined with cooling water installations such as a cooling load 9, a cooling tower 10 and a cooling water pump 11, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a combined heat utilization plant comprising power generation equipment and air conditioning equipment.

[Conventional technology]

Combined heat utilization plants are broadly divided into power equipment that drives a prime mover or generates electricity by burning fuel, and equipment that recovers waste heat energy such as exhaust gas or heated waste water from these power engines to be used as power again. Consists of subordinate heat utilization equipment.

Conventionally, various heat recovery devices have been installed in this type of plant for the purpose of improving thermal efficiency, and methods for recovering surplus thermal energy have been put into practical use.

As related to these exhaust heat recovery methods, for example, as shown in Japanese Patent Application Laid-Open No. 61-279706, thermal energy in the exhaust gas of an internal combustion engine is recovered as generated steam by a boiler, and a steam turbine is activated. There is a plant configuration that drives and obtains electric power.

[Problem to be solved by the invention]

However, in terms of economy, a combined heat utilization plant will not be viable as a facility unless its thermal efficiency is significantly higher than that of a large-capacity single heat utilization plant such as a thermal power plant, for example. An important point is how to maximize and effectively recover and reuse surplus energy from power equipment.

In the above-mentioned conventional technology, the exhaust heat of the internal combustion engine is used to generate electricity again to utilize the heat, while the heat energy of the exhaust steam of the steam turbine is still being disposed of by cooling water in the condenser to the outside of the plant cycle. It's gone.

Normally, the thermal energy that is discarded to the cooling water side in the condenser is a large amount, about 60 to 80% of the thermal energy at the steam turbine inlet. It cannot be said that the results are satisfactory, and there remains some dissatisfaction.

An object of the present invention is to effectively recover heat loss energy lost in a condenser in a steam turbine section of a heat utilization plant, thereby improving the thermal efficiency of the entire plant.

(Means for solving the problem) The above purpose is to supply the condensed water in the condenser of the steam turbine to the absorption chiller as heat source hot water, and to return the outlet water from the chiller to the condenser. This is achieved by providing a water recirculation system.

(Function) In the case of a steam turbine, in order to cool and condense the turbine exhaust steam, it is necessary to remove the latent heat of the steam with low-temperature cooling water.On the other hand, in an absorption refrigerator, in order to produce cold water for cooling, On the contrary, it is necessary to provide thermal energy.

In this way, there is an inverse relationship between the exchange of thermal energy between the steam turbine condenser and the refrigerator, and the condensate re-circulation between the condenser and the refrigerator reduces the amount of heat that would otherwise be lost to the steam turbine. The aim is to convert waste heat energy into heat energy for cooling.

The process of transferring thermal energy is shown below. ■Condenser The condensate water is supplied to the refrigerator as a heat source water, and the heat energy of the condensate is absorbed by the refrigerator, which lowers the temperature of the return water. ■The returned low-temperature water is led to the condenser and is ejected into the condenser to directly cool and condense the steam discharged from the turbine through contact cooling. ■The temperature of the low-temperature water rises due to thermal energy given from the turbine exhaust steam, and it is sent to the refrigerator again as heat source hot water.

(Example〕 An embodiment of the present invention will be described below with reference to FIG.

Figure 1 shows a typical system in which a recovery boiler 2 is installed in the exhaust gas line of a gas turbine 1, heat is recovered from residual thermal energy in the exhaust gas as generated steam, and the steam is guided to a steam turbine 3 where a generator 4 generates electricity. It combines a heat recovery power generation plant, a refrigerator 8 that supplies chilled water to a cooling load 9 and absorbs heat, and absorption chiller equipment consisting of cooling water equipment such as a cooling tower 10 and a cooling water pump 11. A combined heat utilization plant is shown.

The exhaust steam from the steam turbine 3 is cooled and condensed in a condenser 5, and is sent to the recovery boiler 2 by a feed water pump 6 as make-up water for generated steam.

On the other hand, a part of the condensate is also sent to the refrigerator 8 by the circulation pump 7, and after passing through the refrigerator, is recovered to the condenser 5 again. This water horse @ ring cycle between the condenser 5 and the refrigerator 8 performs the following functions.

Absorption refrigerators require hot water at approximately 85°C as a heat source in order to evaporate and condense the refrigerant inside the machine to create cold water for air conditioning. Therefore, in order to use the condensate of the steam turbine condenser as the heat source hot water for the refrigerator, the condenser must have a cooling capacity that can maintain the pressure inside the saturator such that the condensate temperature after condensing the turbine exhaust steam is 85°C. It can be determined as having.

When the hot water at 85°C thus obtained is supplied to the refrigerator, the thermal energy is lost in the refrigerator and the water returns as outlet water at a low temperature of 80°C. The condenser is a direct contact type condenser that cools and condenses steam by bringing cooling water into direct contact with steam.
The low-temperature return water from the refrigerator is used as a cooling water source and is sprayed into the condenser to cool the turbine exhaust steam. At this time, the temperature of the water returned from the refrigerator in the condenser increases to 85° C. by absorbing the thermal energy of the steam, and the water is sent to the refrigerator again.

In this way, the condenser and the refrigerator exchange heat energy through closed-cycle hot water recirculation, and this embodiment has the following effects.

(1) Thermal energy that was conventionally wasted outside the plant by cooling water supplied for cooling and condensing the exhaust steam of the steam turbine can be 100% effectively recovered as a heat source for the cooling chiller, and the total The efficiency of the combined heat utilization plant will improve.

(2) A dedicated cooling water supply facility for the steam turbine condenser is not required, reducing construction costs.

Here, regarding the effect in terms of plant efficiency in the above item (1), the degree of improvement will be explained in detail with reference to FIG. 2.

FIG. 2 shows a thermal balance chart showing the state of effectively utilized energy and lost energy with respect to the total input energy.

In the plant configuration shown in FIG. 1 of the example, the thermal energy input as fuel to the gas turbine, which is the prime mover, is
00%, in a conventional heat recovery plant up to a steam turbine, the heat recovery rate is very small at about 27% for power generation, as shown by the broken line in Figure 2, while in a condenser it is A very large amount of heat energy, approximately 35%, is wasted as cooling water loss.

When heat is recovered to the refrigerator as in this embodiment, in addition to the heat recovered as generated power, there is also heat recovery as a cooling load in the refrigerator, as shown by the solid line, and the heat recovery rate is In fact, the total amount is about 50%, and it can be seen that the plant efficiency has been improved by a large 1 [1]. In addition, in this trial calculation, the efficiency of the refrigerator with the actual effective cooling load relative to the supplied energy is taken into account, so the overall efficiency is lowered, or the steam turbine side uses 100% of the received thermal energy for multiple purposes.

FIG. 3 shows a modified example of FIG. 2 in which a heating load is added.

The plant configuration is similar to that shown in Fig. 2, and in this example, the circulation pump 7
A part of the condensed water at the outlet is also supplied to the heating load, and the return water is collected in the condenser 5 like the frozen TA8. The relationship between the heating load and the condenser 5, and its functions are the same as those described in the embodiment shown in FIG.

In addition, in this example, cooling water line equipment is further provided in which the cooling water from the cooling tower 10 for cooling the refrigerator is also supplied to the condenser 5 and returns to the cooling tower 10 again through the heat exchanger tube 13. .

This embodiment is suitable for the configuration as a cogeneration plant for district heating and cooling, and has the operating characteristics shown in FIG. 4 with respect to cooling and heating loads that change over time.

In FIG. 4, (A) shows changes in the general required amount of cooling load and heating load for each month of the year. In (B), the solid line shows the total regional power demand for the entire regional facility, which is the sum of these heating and cooling demands and other power demands of the regional facility. In this example, as mentioned above, the heating and cooling load is actually covered using the exhaust heat of the steam turbine, so the local power demand is (B).
It decreases as shown by the two-dot chain line in the middle. Since the heat utilization plant generates power as shown by the dashed line, the amount of electricity that should be purchased from the external power company is the amount shown by the hatching, which is obtained by subtracting each amount of electricity in the dashed line curve from the two-dot chain line curve. This has the advantage of providing stable operating characteristics and allowing the power receiving device to be made smaller. Next, (C) shows the thermal energy of the steam turbine exhaust steam and the energy supplied to the air-conditioning facility corresponding to the air-conditioning load shown in (A) when the heat utilization plant is operated continuously at the rated value.

The difference in these thermal energies, that is, the heat amount of the hatching part, is surplus energy, which needs to be cooled and condensed using cooling water from another source in the steam turbine condenser. In this case, since it is the time when cooling water is required, the load on the refrigerator is small, or the refrigerator is inactive, some or all of the cooling tower water for the refrigerator is condensed. It can be used as cooling water for containers. For this reason, the condenser is either a direct contact type or has a cooling tube for heat exchange inside, and the cooling tower water is supplied as cooling water by bypassing the refrigerator to cool excess turbine exhaust steam. Of course,
It is also possible to operate the heat utilization plant so that the power generation amount, that is, the exhaust heat energy of the steam turbine, is commensurate with the energy supplied to air conditioning.In this case, the cooling water loss in the condenser is small and the plant thermal efficiency is high. can be maintained.

In this embodiment, in addition to recovering the thermal energy that was conventionally wasted by cooling the steam turbine exhaust for a multipurpose purpose, the cooling tower cooling water equipment for the refrigerator is also used to generate electricity for local equipment, or It is possible to have operational flexibility according to heat demand.

【Effect of the invention〕

According to the present invention, the residual thermal energy of the steam turbine exhaust steam can be reused as a heat source for district cooling and heating equipment, and the heat utilization efficiency can be greatly improved as a cogeneration plant.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a combined heat utilization plant according to an embodiment of the present invention, FIG. Figure 4 is a diagram showing the relationship between electric power demand, power generation amount, heating and cooling load, etc. 1... Gas turbine, 2... Recovery boiler, 3...
Steam turbine, 4... Generator, 5... Condenser, 6...
... Water supply pump, 7 ... @ ring pump, 8 ... Absorption refrigerator, 9 ... Cooling load, 10 ... Cooling tower, 11 ... Cooling water pump, 12 ... Heating load, 1
3...Cooling water tube. Figure 1 Figure 2 (α) Gorin (de) Gorin Diagram Funeral Map? Month

Claims (1)

[Scope of Claims] 1. In a cogeneration plant including a condensing steam turbine, a condensing system is used to reuse the thermal energy of the exhaust steam of the condensing steam turbine for the load of an absorption chiller or the heating load. A combined heat utilization plant characterized in that condensate from a water heater is supplied as a heat source, and the return water is used to cool and condense steam discharged from a steam turbine. 2. The combined heat utilization plant according to claim 1, wherein a circulation line for recirculating condensate is provided between the condenser and the absorption chiller or heater. 3. The condenser is either a direct contact type that cools and condenses the steam turbine exhaust steam through direct contact with the return water from the absorption chiller or the heater, or a cooling tube that cools the steam turbine auxiliary through indirect contact. The combined heat utilization plant according to claim 1, which is a combined type in which a combined heat utilization plant is also provided with.