Rankine cycle power generation system and a method for operating the same

A high efficiency and economic refuse incineration power generation system capable of stable and continuous refuse incineration operation which can adapt to fluctuation in calorific values in the refuse incinerator has been provided, wherein the same system comprises the refuse incinerator having the heat exchanger through which the medium flows, the steam turbine which is coupled to the generator, and the refrigerator which supplies cooling water to the condenser, and wherein the medium discharged from the steam turbine is circulated to the boiler via the condenser where the medium is condensed to a condensate by enhanced cooling, a portion of the vapor generated in the refuse incinerator is branched in the upper stream of the steam turbine to be supplied to the refrigerator, and the working medium discharged from the refrigerator is caused to converge with the medium flow discharged from the condenser.

BACKGROUND OF THE INVENTION 
The present invention relates to refuse incineration exhaust heat power 
generation system (hereinafter referred to as refuse incineration exhaust 
heat power generation system or simply refuse power generation plant), and 
in particular, it relates to a Rankine cycle power generation system 
suitable for achieving a high-efficiency refuse power generation plant. 
At present, most of combustible municipal waste or refuse are disposed 
through incineration by each community, and exhaust heat obtained during 
incineration is utilized to produce hot water or steam to supply to public 
bath, hot water pool and power generation, or the like. 
Nowadays, with changing life styles and growing utilization of office 
automation equipment, volumes of combustible refuse or waste such as paper 
trash, and in consequence, calorific values due to refuse incineration are 
on the increase. On one hand, finding and securing of further dumping 
sites, although it is very pressing, is becoming very difficult. In 
particular, in urban communities, such a situation as above poses a 
serious social problem. 
On the other hand, electric power demand is increasing significantly every 
year, and in particular, the electric power demand during summer season 
and, in particular, day-time in urban cities is substantially increasing 
due to an increasing number of air-conditioners in home, thereby, 
construction or addition of new power generation installations is obliged 
in order to supplement such increases in the power demand. 
Thereby, as one approach to solve such problems as described above 
associated with urban cities, and further to help solve the global 
environmental problems, each community and municipal organization are 
regarding municipal waste and refuse as a useful and valuable resource, 
and discussing introduction of refuse power generation plants which use 
steam obtained by recovering exhaust heat from refuse incineration. 
In refuse power generation plants, however, in most cases there are 
included corrosive components such as chlorine gas in exhaust gases from 
refuse incineration, thereby, heat transfer piping in a steam generator 
for recovering exhaust heat from such exhaust gas is very likely to be 
corroded. Since such corrosion of the heat transfer piping becomes 
significant with increasing temperatures, the temperature of steam at 
turbine inlet in the refuse incineration exhaust heat power generation is 
limited to approximately 300.degree. C. at highest. 
As one solution to solve the above problem, Japanese Patent Application 
Laid-Open No.5-10107 discloses a method for improving power generation 
efficiency through steps of superheating the steam obtained from refuse 
incineration exhaust heat with a high-temperature exhaust gas which has 
been discharged from a gas turbine after having driven the turbine, and 
admitting a superheated steam thus obtained into a steam turbine to 
generate electricity. 
However, since the foregoing power generation system needs a gas turbine 
power generation system in addition to a refuse incineration steam turbine 
power generation system, a substantial increase in installation cost is 
unavoidable. Further, costly fuels such as various types of gasses, oil 
and the like will be needed to operate such plants. 
Still further, there are such problems as follows. Since such steam turbine 
power generation system and gas turbine power generation system are 
coupled closely, a highly sophisticated operational technique and a very 
stringent maintenance control are required, and in case the gas turbine 
generation system halts its operation due to some cause, the steam turbine 
power generation system will be forced to operate singly at a very low 
power generation efficiency, or in a worst case, the operation of a refuse 
incinerator will have to be halted, thereby significantly impairing the 
proper refuse disposal operation. 
On the other hand, it is very seldom for such refuse power generation 
plants to be sited in regions along the coastline as industrial power 
generation plants. By and large, in consideration of a responsible area to 
cover to collect refuse, they are sited in areas relatively remote from 
the coastline where cooling water including sea water is available. In 
addition, utilization of river water is avoided as much as possible to 
prevent infringement on the right of water and the like. Thereby, as to a 
condenser for condensing exhaust steam from the steam turbine, air-cooled 
condensers are presently preferred in most cases. Therefore, a condensing 
temperature available for condensing steam turbine exhaust by cooling in 
this system is usually limited to approximately 60.degree.-70.degree. C. 
(saturation pressure at this time: 0.2-0.3 kg/cm.sup.2), the values of 
which are substantially higher compared to those of the temperature and 
pressure of the exhaust from usual industrial large-scale power generation 
plants in which sea water or the like is used as a cooling water to cool 
the condensing temperature as low as 30.degree.-40.degree. C. (saturation 
pressure at this time: 0.04-0.08 kg/cm.sup.2) 
Thereby, in the conventional refuse power generation plant, a low 
efficiency Rankine cycle operation is obliged due to the aforementioned 
limitations. 
On the other hand, in order to solve such problems, there may be conceived 
a cooling tower/water-cooled condenser system which combines a cooling 
tower and a water-cooled condenser to condense the steam turbine exhaust 
at a temperature lower than obtainable in the air-cooled condenser. This 
system, however, requires installation of an additional cooling tower 
which will increase the installation cost substantially, thereby it is not 
practical. 
Moreover, in the refuse power generation plant, since calorific values vary 
substantially due to the nature of the refuse and waste to be incinerated, 
it is known that a quantity of steam generated undergoes a change with 
time relative to a constant feed of refuse to the incinerator. Thereby, 
there is adopted such a method whereby a portion of the steam generated is 
constantly discharged out of the power generation system, and a quantity 
of the steam to be discharged is controlled such that a steam to be 
supplied to the steam turbine is maintained at a predetermined value 
constantly. Thereby, there is such a disadvantage that a portion of the 
useful steam having been produced as a result of recovery of the refuse 
incineration exhaust heat is discharged without contributing to electric 
power generation, thereby unwisely wasting the refuse incineration 
recovery heat, and reducing the thermal efficiency in long run. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a Rankine cycle power 
generation system capable of improving the Rankine cycle efficiency in the 
refuse power generation plant which can adapt to changes or fluctuation in 
calorific values obtainable in refuse incinerators and further take into 
account economic power generation. 
According to the invention, the aforementioned problems associated with the 
prior art are solved, and a refuse incineration exhaust heat power 
generation system can be provided that is capable of generating 
electricity with an improved efficiency and utilizing the steam obtainable 
from the refuse incineration exhaust heat most effectively. 
In a Rankine cycle power generation system according to the invention 
having a boiler including a heat exchanger through which a medium flows, a 
steam turbine coupled to a generator, and a condenser in which a steam of 
the medium discharged from the steam turbine is condensed and from which a 
condensate is recirculated to the boiler, the boiler may be a refuse 
incinerator in which a total volume of steam of the medium vapor produced 
will change relative to a constant input of fuel supply, a predetermined 
amount of steam which is smaller than a minimum total amount of steam 
available as a result of the fluctuation is supplied to the steam turbine, 
and a surplus amount of steam of the medium exceeding the foregoing 
predetermined amount (including a fluctuating portion), after having 
worked to damp the fluctuation (for example, by damping the fluctuation 
through condensing the steam into a liquid (condensate)), is converged 
with the medium returned from the condenser. 
The aforementioned refuse incinerator in which the amount of steam of 
medium produced undergoes a change relative to a constant fuel supply 
amount may include such an instance in which a calorific value (or steam 
production) fluctuates with time even during a steady state operation of a 
boiler, or in which the calorific value (or steam production) fluctuates 
relative to a unit weight(or volume) of fuel (refuse) input. 
The foregoing predetermined amount of steam and the extra amount of steam 
exceeding the predetermined amount can be defined in distinct relative to 
a total amount of steam generated in the refuse incinerator as 
schematically illustrated in the drawing of FIG. 10. Even under a constant 
state of operation of the refuse incinerator, the steam produced will 
undergo a fluctuation as shown in the drawing. Further, the foregoing 
predetermined amount of steam is preferably changed according to a 
particular time zone of the day. For example, it may be changed according 
to plural time zones of the day divided into 2 or more. Further, even when 
ther arises an instance the steam turbine will have to be stopped, for 
example, by failure or for inspection, the predetermined amount of steam 
to be supplied to the steam turbine can be cut off its supply and is 
supplied to a refrigeration unit, thereby the refuse incineration is 
ensured to continue its operation. 
According to the invention as described above, from any incinerator such as 
a refuse incinerator in which the steam production amount fluctuates with 
time relative to a constant input of fuel (refuse), a stable amount of 
steam can be supplied to a steam turbine, and such fluctuation can be 
moderated as well thereby ensuring the medium to be recirculated stably. 
Further, according to the invention, there is provided a refrigerating unit 
which supplies a cooling water to the condenser, and a portion of steam of 
the medium produced in the refuse incinerator is branched in the upper 
stream of the steam turbine to be supplied to the refrigeration unit as a 
heat source, and then a flow of condensate of the medium condensed in the 
refrigerating unit is converged with a flow of the medium discharged from 
the condenser. The foregoing refrigerating unit is preferably an 
absorption refrigerator. 
According to the invention, the exhaust heat produced in the refuse 
incinerator can be utilized most effectively, and loss of heat can be 
minimized. 
The refrigerating unit is preferably provided with a storage vessel for 
storing a cooling water or cold water producing source. 
The cold water producing source is such a substance that generates a 
cooling water. In the absorption refrigerator, it is a strong absorption 
solution and a refrigerant, and in particular, the strong absorption 
solution. In a compression refrigerator, it is a compressed refrigerant, 
for example. Further, preferably, they can be stored in a container or the 
like. 
The refrigerator of the invention is provided with an absorption liquid and 
a refrigerant liquid, a weak absorption solution diluted by the 
refrigerant liquid is heated by the medium vapor supplied thereto to be 
concentrated and separate the refrigerant. A strong absorption liquid and 
a separated refrigerant liquid obtained above are used as a new cold water 
producing source for cooling the cooling water returned from the 
condenser, or stored temporarily in respective storage vessels for the 
absorption liquid and refrigerant liquid. They can be used afterward on 
demand for cold water production. The cooling water is adapted to 
recirculate between the condenser and the refrigerator. 
Further, it can be arranged according to the invention such that a direct 
contact (mixing) is prevented between the absorption solution or 
refrigerant of the refrigerator and the medium which recirculates from the 
refuse incinerator, turbine condenser, to the refuse incinerator. Thereby, 
corrosion of the heat exchangers in the refuse incinerator and the other 
parts can be suppressed substantially. 
The foregoing condenser has a function to condense the medium vapor (gas) 
produced in the refuse incinerator into a liquid. When the medium is 
water, it condenses steam into water. 
According to the invention, a junction at which two medium flows converge 
is placed between the condenser and the refuge incinerator, thereby the 
medium having a low temperature from the condenser and the medium having a 
high temperature from the refrigerator are converged before introducing 
into the refuse incinerator. Thereby, since the medium discharged from the 
condenser is preheated before it is returned to the boiler, the amount of 
steam production can be increased to ensure a high-efficiency operation. 
In addition, the refrigerator of the invention can be operated at an 
improved efficiency. Further, there may be provided a mixer 910 as shown 
in FIG. 11 for mixing converging medium flows having different 
temperatures to have a uniform temperature in the downstream thereof. 
The refuse incinerator according to the invention is such one that produces 
heat by incinerating combustible refuse and waste. The refuse incinerator 
suitable for implementing the invention is preferably such one that is 
essentially capable of a continuous operation. For example, it is an 
incinerator that is capable of continuous operation throughout 
night-and-day except for a predetermined instance for a maintenance or the 
like. The foregoing refuse may include home garbages/combustibles, 
industrial combustible wastes or anything that can be disposed of by 
incineration. 
The foregoing medium may be anything so long as the liquid of which can be 
heated by the heat exchanger in the incinerator into a vapor that can be 
introduced to the steam turbine. For example, it may be water or a liquid 
having water as a main component. 
According to the invention, a portion of heat produced in the refuse 
incinerator can be utilized in the refrigerator, for example, in 
concentration of a weak absorption solution therein. That is, heat can be 
supplied to the refrigerator as a heat source. For this purpose, heat may 
be supplied to the refrigerator by means of conversion to another medium. 
The foregoing medium or its vapor (steam) is branched in the upperstream of 
the steam turbine where an adjusting mechanism is provided for adjusting 
steam flow, thereby an amount of the vapor to the steam turbine and an 
amount thereof to the refrigerator can be controlled. 
For example, it can be arranged such that in a time zone when a unit price 
of electricity is low, amount of supply to the steam turbine is reduced, 
and in another time zone when a unit price of electricity is high, the 
amount of supply to the steam turbine is increased. Further, it can be 
also arranged such that a predetermined amount of steam is secured to be 
supplied to the steam turbine, and a surplus amount thereof is supplied to 
the refrigerator which is effectuated to absorb such fluctuation in the 
steam production. Thereby, even under preence of fluctuation of calorific 
values in exhaust heat from refuse incineration, the steam turbine can be 
operated steadily with stable supply of steam. The aforementioned branch 
junction can be provided with a flow regulating mechanism or flow 
controller which, upon calculation of an appropriate amount of steam to be 
introduced into the turbine in order for at least one of a steam supply 
amount to the turbine, a steam turbine output and a generated electricity 
to be set at a preferred value, adjust the flow of the predetermined 
amount of steam to the steam turbine and the flow of the surplus amount of 
steam to the refrigerator. Thereby, the remaining steam exceeding the 
predetermined amount for the turbine can be supplied to the refrigerator. 
The aforementioned branch portion can divide the medium flow from the heat 
exchanger of the refuse incinerator into a flow line leading to the steam 
turbine and another flow line leading to the refrigerator. Since the 
medium is branched in the state of steam, the amount of steam to be 
supplied to the turbine can be easily adjusted. The medium may be branched 
into a steam turbine supply line and a refrigeration supply line in the 
heat exchanger as well. 
It may also be arranged such that the medium is branched before entering 
the heat exchanger into the steam turbine supply line and the refrigerator 
supply line, and each of the branched medium enters each heat exchanger 
provided separately. In this arrangement, since the medium is branched in 
the liquid state still at a relatively low temperature, such mechanical 
properties, heat resistance, strength and the like as required for the 
branch portion facility in the foregoing arrangement will not be 
necessary, and materials with properties adequate for lower steam 
condition will suffice. Prerequisite conditions such as amount of steam of 
the medium to be supplied to the steam turbine and the like can be 
calculated, for example, from the temperature in the refuse incinerator, 
flows of the medium or the vapor thereof and the like, so as to adjust 
each medium flow in each supply line. 
According to the invention, even when the amount of medium steam production 
in the refuse incinerator fluctuates, substantial changes in steam flow to 
the steam turbine can be suppressed, that is, a predetermined steam flow 
can be secured to supply to the steam turbine, by regulating the steam 
flow to supply to the refrigerator such as to absorb the fluctuation, and 
further by converting the medium vapor to liquid in the refrigerator, 
which is then converged with the medium discharged from the condenser, 
thereby ensuring a stable operation of the steam turbine free from 
fluctuation in vapor supply. 
Further, according to the invention, it may also be arranged such that heat 
is supplied in another form of energy, that is, a combustion gas exhausted 
from the refuse incinerator is coupled to the refrigerator unit to supply 
heat directly. The aforementioned combustion gas is a combustion exhaust 
gas produced by refuge combustion. This arrangement ensures more steam of 
the medium produced to be used in generation of electricity, since steam 
flow of the medium to the refrigerator can be reduced compared to the 
former arrangement. This is further advantageous in that more compact 
equipment in size can be provided. 
Still further, according to the invention, it may be arranged such that the 
foregoing refuge incinerator includes the foregoing heat exchanger (which 
may be defined as a first heat exchanger) and a second heat exchanger 
through which a second medium flows, wherein the second medium flowing 
into the second heat exchanger is directed from the second heat exchanger 
to the refrigerator. 
The second medium may have the same composition as the first medium, 
however, it is desirable that the first medium and the second medium are 
provided in a separate independent system respectively, and will not mix 
each other in their operation. The second medium flowing through the 
second heat exchanger can contribute to the operation of the refrigerator 
as well. 
Further, it may be arranged according to the invention such that at least 
either one of the foregoing medium, the foregoing medium vapor and the 
foregoing combustion gas to be supplied to the refrigerator is caused to 
pass through a heat exchanger to exchange heat with the medium discharged 
from the condenser before entering the refrigerator. Since the medium, 
after being raised its temperature, is recirculated to the refuse 
incinerator, calorific power required for subsequent steam generation can 
be reduced. 
There may be provided a cooling water reservoir for storing the cooling 
water which circulates between the refrigerator and the condenser. The 
cold water produced in the refrigerator can be stored temporarily and 
recovered on demand. 
A portion of the cooling water produced in the refrigerator can be arranged 
to recirculate between a load and the refrigerator. The load may include 
cold source to serve a demand within the refuse power generation plant 
system or outside the system. 
At least a portion of the foregoing medium may be arranged, after it has 
been supplied to the refrigerator, to be circulated to the refuse 
incinerator further via a load. 
Further, it is possible to supply a cold water produced in the refrigerator 
to a customer as a cold source for air-conditioning controlling the amount 
of supply of the cold water with time. 
In the case of supplying of heat to the refrigerator, the heat of the 
exhaust gas from the refuse incinerator may as well be supplied as a hot 
water produced by heat exchange. 
Next, there has been contemplated an operating method according to the 
invention for operating a Rankine cycle power generation system which 
includes the steps of producing heat in a boiler, obtaining a vapor 
(steam) of a medium which is introduced into the boiler, operating a steam 
turbine coupled to an electrical power generator to produce electricity, 
condensing the vapor (steam) of the medium discharged from the steam 
turbine to obtain a condensate which is recirculated to the boiler, and 
using a cooling water produced in a refrigerator for condensing the vapor 
of the medium, wherein the boiler is a refuse incinerator, and wherein a 
portion of the vapor of the medium produced in the boiler is used to drive 
the steam turbine to generate electricity, and another portion or the rest 
of the medium vapor is used to obtain a cooling water or a cold source for 
obtaining the cold water. Further, a day is divided into at least two time 
zones of a first time zone and a second time zone, and a power generation 
in the second time zone is reduced compared to in the first time zone, 
however, an amount of cold water or cold source therefor is increased in 
the second time zone instead thereof, and the cooling water or cold source 
obtained in the second time zone and stored is used in the first time 
zone. 
By way of example, preparation of the cold source may be understood to be 
equivalent to obtaining a strong absorption solution by heating and 
concentrating a weak absorption solution and/or to separate refrigerant in 
the case of the absorption refrigeration. In the case of the compression 
refrigeration, it is meant to obtain a compressed refrigerant, for 
example. 
For example, the foregoing first time zone may be assigned to a particular 
time zone of the day during which a unit price of electricity is high, and 
the second time zone to a time zone during which a unit price of 
electricity is low. The cooling water or cold source for producing cooling 
water which has been obtained during the second time zone is utilized for 
the condenser in the first time zone, thereby, in the first time zone, a 
quantity of heat necessary for obtaining the cooling water or cold source 
in the refrigerator can be reduced, thereby more portion of the medium 
vapor produced in the boiler can be supplied to the steam turbine to 
achieve a high-efficiency power generation. 
Further, heat generated in the refuse incinerator is collected as steam, a 
predetermined amount of which steam is used to drive the steam turbine to 
generate electricity, and surplus steam in addition to the predetermined 
amount of which steam is used to operate the refrigerator to obtain the 
cooling water or cold source therefor. 
According to the invention, heat from refuse incineration has been utilized 
fully and most effectively even under existence of fluctuation in 
calorific values due to incineration of refuse and waste. Further, this 
operating method of this embodiment of the invention is used in 
conjunction with the aforementioned operating method of the preceding 
embodiment which changes operating conditions by the time zone of the day 
so as to ensure more efficient operation. 
The refrigerator or refrigeration facility according to the invention is 
preferably such one that produces a cold water having a temperature in a 
range from 0.degree. to 20.degree. C. The range of temperature may also 
include 10.degree.-20.degree. C. or 15.degree.-20.degree. C. Thereby, 
turbine exhaust temperature and pressure according to the invention can be 
reduced lower than the conventional exhaust temperatures and pressures. 
There are provided so-called heat storage facilities which may include, 
for example, cold water storage, or cold storage unit which may include a 
reservoir for a cold source for producing cooling water; in the case of an 
absorption refrigerator, storage units for a strong absorption solution 
and a refrigerant, in particular, for a strong solution, or for a 
concentrated refrigerant. Further, it is advantageous to alternately or 
concurrently carry out a most efficient power generation mode utilizing 
equipment dedicated to electricity generation by supplying most of the 
vapor of medium produced to the turbine to generate electricity with 
assistance of heat dissipation action of cold water stored in the 
reservoir of the heat storage facility (i.e., through enhanced cooling of 
the steam turbine exhaust gas in the condenser), and a most efficient heat 
storage operation mode for storing heat in the heat storage facility, for 
example, by supplying most of the vapor of the medium to drive the 
refrigerator, so that production of electricity may be changed at 
discretion, thereby, the refuse incineration exhaust heat power generation 
plant can perform a high efficiency operation. 
As the foregoing refrigerator, an absorption type refrigerator (absorption 
type heat engine) can be applied. Depending on a system structure, a 
compression refrigerator may also be applied. 
As a mode of operation to drive equipment using refuse incineration exhaust 
heat, there are such modes of operation: exhaust gas driving (for example, 
absorption type); steam driving (for example, absorption, compression 
types); hot water driving (for example, absorption type); and the like. 
The foregoing process of supplying the medium vapor to drive the 
refrigerator is to operate the refrigerator, for example, by applying heat 
to an absorption refrigerator to concentrate a weak absorption solution to 
obtain a strong absorption solution, and/or to produce a cooling water 
(cold water) through use of the preceding process. It may also include 
such a process to use the vapor of the medium to drive a refrigerant 
compressor installed in the compression refrigerator. 
With reference to FIG. 9, a schematic diagram of an absorption refrigerator 
suitable for implementing the invention is illustrated. Refrigerator 5 is 
comprised of evaporator 73 for evaporating a refrigerant which may be 
water, concentration vessel 54 for concentrating an absorption solution 
which may be a LiBr solution, for example, absorption chamber 55 in which 
vapor of the refrigerant solution is absorbed, and condenser 56 for 
condensing a vapor of the refrigerant solution generated when the 
absorption solution is condensed, and wherein the absorption chamber 55 
and the condenser 56 are arranged to be cooled by heat exchanger unit 50 
through which heat is exchanged with external air. 
After non-condensing gas has been purged out of the system, a driving steam 
(for heating) is admitted through line 120 into absorption solution 
heating piping of heat exchanger 52 inside condenser 54, and a weak 
absorption solution flowing through line 550 into the condenser is 
dispersed to contact with the absorption solution heating piping therein 
thereby to be heated. The vapor of the solution evaporated by heating 
therein is directed through line 521 into condenser 56 to be condensed by 
means of air heat exchanger 50 (air blower is not shown in the drawing). 
An amount of the vapor generated corresponds to a concentrated portion of 
the absorption solution. A strong absorption solution concentrated through 
the foregoing action is directed through line 540 into absorption chamber 
55 to be dispersed therein. Further, the strong absorption solution being 
dispersed inside the absorption chamber 55, since it is cooled by the air 
heat exchanger 50 as described above, is in a state of a low vapor 
pressure, thereby the pressure inside the absorption chamber 55 has a low 
value. Since the absorption chamber 55 and evaporator 73 are communicative 
with each other coupled by pipeline 531, the low pressure described above 
propagates to the evaporator 73. Thereby, a refrigerant liquid flowing 
through pipeline 560 into the evaporator 73 to be dispersed therein and to 
contact with the outer surface of cooling water generating heat exchanger 
51 in the evaporator 73 is caused to evaporate at a low temperature, and a 
vapor generated in this manner is admitted through pipeline 531 to the 
absorption chamber 55 to be absorbed into the strong absorption solution. 
Further, there is provided absorption solution reservoir 53. The 
absorption solution reservoir 53 includes absorption solution vessel 71 
for storing a concentrated strong absorption liquid and refrigerant liquid 
vessel 72 for storing a condensed refrigerant liquid. 
The refrigerant liquid in contact with the outer surface of the cooling 
water generating heat exchanger 51 and evaporating at a low temperature 
receives heat from cooling water 511 which has cooled the condenser and is 
flowing through piping of the cooling water generating heat exchanger 51. 
In other word, cooling water 511 having cooled the condenser and is 
flowing through piping of the cooling water generation heat exchanger 51 
is caused to drop its temperature by dissipating its heat and flow to the 
condenser through pipeline 510. 
Through the process of operation described above driven by the steam 
supplied from pipeline 120, cold water is supplied in turn through 
pipeline 510. 
According to the invention, since a continuous operation is possible 
throughout night-and-day, and it is possible to supply steam for more 
effective use for generating a value-added electricity (i.e., at a higher 
sales price), a Rankine cycle power generation system with an improved 
Rankine cycle efficiency can be provided. More specifically, since it is 
possible to adapt to fluctuation in the calorific values due to refuse 
combustion in the refuse incinerator, and operate night-and-day to supply 
steam more advantageously to generate electricity which can be sold with 
an added value (at a higher unit price), there is provided a Rankine cycle 
power generation plant which can be very economical having an improved 
Rankine cycle efficiency. The specific particulars thereof will be 
described in the following. 
According to the invention it has become possible significantly to drop the 
exhaust temperature of the exhaust vapor of the steam turbine (pressure is 
caused to drop as well naturally) compared to the exhaust temperature in 
the conventional method since the exhaust vapor of the steam turbine can 
be effectively condensed through cooling by the cooling water (cold water) 
which is supplied through operation of the steam-driven refrigerator, 
thereby, a heat drop for the vapor in the steam turbine cycle can be 
maximized in consequence, thereby increasing a unit production of 
electricity per unit steam volume, or in other word, per unit volume of 
refuse even at relatively low steam temperatures (or heat temperature) 
obtainable from the refuse incinerator. 
Further, since the refrigerator is driven by surplus heat energy produced 
in the plant itself, there is no additional cost for energy, thereby an 
increase in the operational cost can be suppressed substantially. 
Still further, it becomes possible according to the invention, while 
maintaining a stable and continuous operation of refuse incineration task, 
to change at discretion or stop generation of electricity on demand. That 
is, when it is opted to sell electricity from the refuse power generation 
plant to the utility company, there are such advantages that in a time 
zone when a unit price of electricity is higher (hereinafter, referred to 
as a unit sales price of electricity on the side of supplier of 
electricity, and a unit purchase price of electricity on the side of 
consumer), the high efficiency full-scale power generation operation 
described above (for example, to maximize the generation of electricity) 
is carried out devotedly, and that in a time zone when the unit sales 
price of electricity is low, generation of electricity is substantially 
suppressed or stopped in turn to supply heat as well as cold from the 
refuse power generation plant to serve a demand inside and outside the 
refuse incineration facilities, thereby improving a profit of selling 
electricity or heat source advantageously. 
Further, through effective operation of the foregoing operational methods 
of the invention, the refuse incineration operation can be properly 
continued without difficulty even when any of the facilities pertaining to 
power generation such as the steam turbine, generator, condenser and the 
like is interrupted of its operation.

DESCRIPTIONS OF THE NUMERALS! 
1 . . . refuse incinerator, 2 . . . steam turbine, 3 . . . generator, 4 . . 
. condenser, 5,5a,5b,5c,7 . . . refrigerator, 6 . . . heat 
drop/decompressor, 8a . . . heat storage, 11 . . . exhaust heat recovery 
heat exchanger, 12 . . . hot water producing heat exchanger, 41...cooling 
pipe, 50,70...air heat exchanger, 51,71 . . . cold water producing heat 
exchanger, 52 . . . absorption solution heating heat exchanger, 52b,52c. . 
. absorption solution heater, 53 . . . absorption solution reservoir 
vessel, 100 . . . refuse and waste, 110,112,120,210 . . . steam line, 121 
. . . exhaust gas line, 130,133,410,520 . . . condensate line, 131,132 . . 
. hot water line, 310 . . . electricity power transmission system, 510,511 
. . . cooling water line, 512,513,810,811 . . . cooling water line, 610 . 
. . water filling line. 
EMBODIMENTS 
Preferred embodiments of the invention will now be described in detail with 
reference to the accompanying drawings in the following. 
With reference to FIG. 1, there is indicated a schematic arrangement and 
piping thereof according to a first embodiment of the invention. Main 
components which constitute the system of the first embodiment include 
refuse incinerator 1, steam turbine 2, generator 3, condenser 4, and 
refrigerator 5 provided with absorption solution storage vessel 53 (the 
refrigerator may be an absorption refrigerator or heat storage absorption 
refrigerator). 
Refuse is input into refuse incinerator 1 to be incinerated therein (other 
facilities associated with the incinerator is not shown in the drawing). 
Combustion exhaust gas obtained therein is used to heat a medium 
(hereinafter referred to as water since in most cases the medium is water) 
flowing through the heat transfer piping of exhaust heat recovery heat 
exchanger 11 so as to generate steam (vapor) thereof. The steam is 
superheated into a superheated steam in a superheater (not shown) of the 
heat exchanger 11, and supplied through steam line 110 to steam turbine 2 
to drive the same. Drive torque thus obtained is used to drive generator 3 
coupled to the turbine 2 thereby to generate electric power. The electric 
power thus generated is supplied to the user or sold to the commercial 
electric power system through electric transmission line 310. 
Steam expanded in the steam turbine 2 is directed to water cooled condenser 
4 (hereinafter referred to as a condenser) through steam line 210. The 
condenser 4 is provided with cooling piping 41. Through the cooling piping 
41 there flows cold water which is produced in refrigerator 5 and supplied 
as a cooling water through cooling water line 510. Thereby, the steam 
flowing through the steam line 210 into the condenser is caused to 
condense upon contact with the heat transfer piping 41. Non-condensing gas 
is purged out of the condenser 4 in advance (related purging equipment is 
not shown) and purging of the non-condensing gas is continued during 
operation, thereby a pressure inside the condenser 4 is maintained at a 
saturation pressure corresponding to the condensing temperature of steam 
therein. 
Condensate from the turbine exhaust steam which has been condensed in the 
condenser 4 is recirculated to the exhaust heat recovery heat exchanger 11 
through condensate lines 410 and 130 to become steam once again (other 
facilities, descriptions thereof and drawings associated with the boiler 
feedwater system are omitted). 
The cooling water which has been subjected to condensate heat of the 
turbine exhaust steam and increased its temperature is returned through 
cooling water line 511 to cold water producing heat exchanger 51 in the 
refrigerator 5. The foregoing refrigerator 5 is an absorption heat engine 
(hereinafter referred to as an absorption refrigerator or simply as a 
refrigerator). According to the principles of operation of the foregoing 
absorption refrigerator, heat having been collected in the condenser and 
dissipated from the surface of the heat exchanger 51, is further 
dissipated through action of the absorption liquid through air heat 
exchanger 50 to ambient having a higher temperature than the temperature 
of the cooling water flowing the lines 511 and 510. 
The above-mentioned mode of operation is provided by a dilution cycle of 
the absorption solution, thereby an additional process for concentrating 
the absorption solution is also required. A concentration cycle for 
concentrating the absorption solution will be described in the following. 
The steam produced from the refuse incineration exhaust heat is directed 
through steam line 110 and flow control mechanism 180 to heat 
reducer/depressurizing unit 6 (hereinafter referred to as a heat reducer), 
in which its temperature is adjusted by injecting water from water 
injector system 610 of the heat reducer 6, then the steam is directed 
through steam line 120 to absorption solution heating heat exchanger 52 in 
the absorption refrigerator 5, to concentrate by heating a weak absorption 
solution diluted as described above. Then, a strong absorption solution 
concentrated as above is supplied for use in the dilution cycle as 
described above. 
The steam which worked to heat the absorption liquid in the heating heat 
exchanger 52 and became a condensate is directed through condensate lines 
520 and 130 into the exhaust heat recovery heat exchanger 11 in the refuse 
incinerator 1 to become steam once again. 
The basic configuration of the refuse incineration exhaust heat power 
generation system and one example of its operation according to the 
invention have been described hereinabove. Now, advantages of the present 
invention will be described quantitatively in comparison with a 
conventional refuse incineration power generation plant presently in 
operation with reference to Table 1 in the following. 
TABLE 1 
______________________________________ 
CONVEN- 
ITEM TIONAL INVENTION 
______________________________________ 
INLET TEMPERATURE .degree.C. 
250 250 
PRESSURE kg/cm.sup.2 
17.5 17..5 
ENTHALPY kcal/kg 696 696 
OUTLET TEMPERATURE .degree.C. 
69 20 
PRESSURE kg/cm.sup.2 
0.304 0.024 
ENTHALPY kcal/kg 533 467 
WORK LOAD kcal/kg 163 229 
ELECTRICITY kW.h/kg 0.190 0.266 
GENERATED/STEAM 
CONSUMED 
______________________________________ 
Steam conditions at the inlet of the steam turbine for the steam generated 
using the refuse incineration exhaust heat have and inlet temperature of 
250.degree. C. and an inlet pressure of 17.5 kg/cm.sup.2 (1,716 MPa). 
Steam conditions at the outlet of the steam turbine of a conventional type 
using an air cooled condenser have an exhaust temperature of 69.degree. 
C., and an outlet pressure of 0.304 kg/cm.sup.2 (0.030 MPa). In contrast, 
according to the invention, since the condenser 4 is cooled with cold 
water produced in the refrigerator 5 as indicated in FIG. 1, its steam 
conditions at the outlet of the steam turbine 2 are improved significantly 
compared to the conventional type such that its exhaust temperature and 
outlet pressure became 20.degree. C. and 0.024 kg/cm.sup.2 (0.024 MPa), 
respectively. 
The inlet steam condition at the entrance of the steam turbine 2 is the 
same for both the conventional type and the present invention in terms of 
enthalpy, that is, 696 kcal/kg (2914 kJ/kg). On the other hand, while the 
exhaust steam condition at the outlet of the steam turbine 2 in terms of 
enthalpy is 533 kcal/kg (2232 kJ/kg) for the conventional type, it is 467 
kcal/kg (1955 kJ/kg) according to the invention, which value is 
substantially lower than that of the former. Thereby, in terms of work 
calculated as a difference between the steam turbine inlet enthalpy and 
the steam turbine outlet enthalpy (disregarding losses within the 
turbine), while the conventional type achieves 163 kcal/kg (682 kJ/kg), 
the present invention achieves 229 kcal/kg (959 kJ/kg). Further, assuming 
the efficiency of the generator 3 to be 100%, a unit generation of 
electricity per 1 kg of steam produced from the refuse incineration 
exhaust heat is 0.266 kW-h according to the invention whereas it is 0.190 
kW-h according to the conventional type. That is, an improvement in the 
generation of electricity of approximately 40% can be achieved according 
to the invention. 
With reference to FIG. 2, another embodiment of the invention will be 
described. 
The basic structure of the another embodiment is comprised of refuse 
incinerator 1, steam turbine 2, generator 3, condenser 4 and heat storage 
type refrigerator 5a provided with absorption liquid storage vessel 53. 
Likewise as in the drawing of FIG. 1, refuse 100 is delivered to the refuse 
incinerator 1 to be combusted therein, and exhaust gas from its combustion 
is utilized to heat water flowing through piping of exhaust heat recovery 
heat exchanger 11 to generate steam. Respective electric power generation 
plants in FIGS. 1 and 2 can be switched of their operation in accordance 
with a preferred mode of operation in order to serve a particular use 
object of the generated steam and its specific steam condition which is 
defined advantageously depending on a unit sales price of electricity at a 
particular time zone which will be described later. 
The unit sales price of electricity to be sold from this refuse power 
generation plant to the commercial power transmission system, or a 
purchase unit price of electricity from the viewpoint of the electric 
power supply industries, is divided according to a weekday or holiday, and 
daytime or night-time, and a unit price during daytime of a weekday is set 
substantially higher than that on a holiday and during night-time. 
In other word, the value of refuse 100 being put into the refuse 
incinerator of the refuse power generation plant of the invention 
throughout the night and day changes high during day time of a weekday and 
low during on a holiday or during night hours. 
Thereby, according to this embodiment of the invention whereby the refuse 
incineration task is continued day and night, it can be arranged such that 
during a day time zone of a weekday when the unit price of electricity is 
high, a high efficiency full-scale generation of electricity is adopted to 
increase sales of electricity, and during night hours when the unit price 
of electricity is low, generation of electricity is minimized or stopped 
so as to be able to supply most of the steam produced in the refuse 
incinerator during this time zone to the refrigerator 5 or 5a as a heat 
source to concentrate the weak absorption solution thereof or the like. 
Further, on a holiday, it is arranged throughout a whole day, for example, 
such that a portion of the steam generated in the refuse incinerator 1 is 
supplied for generation of electricity and the remaining portion thereof 
is utilized for concentration of the absorption solution. 
With reference to FIG. 2, during the daytime zone of a weekday it is 
arranged likewise FIG. 1 such that the steam generated in the exhaust heat 
recovery heat exchanger 11 in the refuse incinerator 1 is further heated 
in a superheating heat transfer piping of the heat exchanger 11 to become 
a superheated steam which is directed through steam line 110 to steam 
turbine 2 to drive the turbine, then exhaust steam from the turbine is 
directed to condenser 4 where it is condensed to a condensate which is 
recirculated through condensate lines 410, 130 into the exhaust heat 
recovery heat exchanger 11 in the refuse incinerator 1. Flow control 
device 180 is provided, not at a branch of the heat exchanger, but apart 
in the vicinity thereof. 
In the drawings of FIGS. 1 and 2, as cooling water for cooling the 
condenser 4, cold water produced in refrigerator 5 or 5a is supplied 
through cooling water line 510. The foregoing cold water is produced 
through a heat dissipation mode operation of the refrigerator 5 or 5a, 
where the heat dissipation mode which will be described later denotes a 
cold water production mode to produce cold water through act of a strong 
absorption liquid which has been concentrated by a heat storage mode 
operation during night hours and through heat dissipation by air cooled 
heat exchanger 50. 
Generator 3 is driven by torque of the turbine to generate electricity, and 
the electricity generated under a high efficiency full-scale power 
generation operational condition is transmitted through power transmission 
line 310 to the commercial power transmission system for sale. 
On the other hand, during night hours of a weekday, a heat storage 
operation as will be described later is performed. Steam generated in the 
piping of exhaust heat recovery heat exchanger 11 in the refuse 
incinerator 1 is directed to temperature reducer 6 through steam line 112 
where its temperature and pressure are adjusted, then the adjusted steam 
is supplied to absorption solution heating heat exchanger 52 in 
refrigerator 5 or 5a. 
During this time zone, related lines and subsystems in the refrigerator 5 
or 5a are in a heat storage mode which is a process to concentrate a weak 
absorption solution, thereby the weak absorption solution in absorption 
solution vessel 53 is concentrated due to a difference of temperatures 
between a heating temperature at the absorption solution heating heat 
exchanger 52 and a cooling temperature at air heat exchanger 50, then a 
strong absorption liquid concentrated above is stored in the absorption 
liquid storage vessel 53. 
Further, on holidays, the foregoing generation of electricity and the 
concentration of absorption solution are performed in parallel throughout 
a whole day, which will be described in detail in the following. 
Firstly, with respect to the operation for generation of electricity, a 
portion of the steam generated in the piping of the exhaust heat recovery 
heat exchanger 11 in the refuse incinerator 1 is superheated in a 
superheater piping of the heat exchanger 11 to provide superheated steam 
which is directed through steam pipeline 110 to steam turbine 2 to drive 
the turbine. Exhaust steam therefrom is directed to condenser 4 and 
condensed therein to a condensate which is recirculated through condensate 
pipelines 410 and 130 to the exhaust heat recovery heat exchanger 11 in 
the refuse incinerator 1. 
As cooling water for cooling the condenser 4 there is supplied cold water 
which is produced in the refrigerator 5 or 5a described above through 
piping 510. The foregoing cold water is produced in the aforementioned 
refrigerator 5 or heat storage absorption refrigerator 5a, more 
particularly, it is produced by subjecting to cooling a strong absorption 
liquid which has been concentrated by a heating process which will be 
described later in air heat exchanger 50. Likewise the preceding example, 
turbine torque drives the generator 3 to generate electricity which will 
be transmitted through electrical transmission system 310 for sale. 
A process for concentrating a weak absorption solution, which is performed 
in parallel with the process for generator of electricity, will be 
detailed in the following. That is, a branched portion of steam generated 
in the piping of the exhaust heat recovery heat exchanger 11 in the refuse 
incinerator 1 is directed through steam pipeline 112 to temperature 
reducer 6 in which its temperature and pressure are adjusted, then the 
adjusted steam is supplied as a heating steam through steam pipeline 120 
to absorption solution heating heat exchanger 52 in the refrigerator 5 or 
5a. A weak absorption solution circulating within a main body of the 
refrigerator 5 or 5a (or a weak absorption solution in absorption solution 
storage vessel 53 may also be admitted into the main body of the 
refrigerator 5 or the heat storage absorption refrigerator 5a) is 
concentrated into a strong absorption liquid due to a difference of 
temperatures available between the heating steam temperature at the 
absorption solution heating heat exchanger 52 and the cooling temperature 
at the air heat exchanger 50. Through this refrigeration cycle a cold 
water is produced to be supplied to the aforementioned efficient power 
generation operation. 
As has been described above, on holidays, the steam generated in the 
exhaust heat recovery heat exchanger 11 in the refuse incinerator 1 is 
divided into portions for use for driving the steam turbine 2 as well as 
for driving the refrigerator 5 or 5a, thereby sales of electricity through 
power transmission line 310 can be continued throughout the whole day. 
Further, since operational conditions for the exhaust heat recovery heat 
exchanger 11 in the refuse incinerator 1 can be modified at discretion, if 
a steam condition suitable for a particular steam requirement at the 
heating heat exchanger 52 can be provided, the aforementioned temperature 
reducer 6 can be eliminated. 
Various advantages and results to be achieved through implementation of the 
mechanical structure, system and operating method of the system according 
to the present invention are summarized in Table 2 and will be detailed in 
the following. 
TABLE 2 
__________________________________________________________________________ 
CONVENTIONAL PRESENT INVENTION 
WEEKDAY & 
OTHER TIME WEEKDAY & 
OTHER TIME 
ITEM DAYTIME 
ZONE TOTAL 
DAYTIME 
ZONE TOTAL 
__________________________________________________________________________ 
ELECTRIC GENERATION 
0.546 0.546 0.709 0.431 
AMOUNT OF REFUSE 
DISPOSED (Kwh/kg) 
ANNUAL OPERATING DAYS 
300 59 359 300 59 359 
(days/year) 
ANNUAL OPERATING 
4200 4416 8616 
4200 1416 5616 
HOURS (h/year) 
ANNUAL GENERATION OF 
2293 2411 2978 610 
ELECTRICITY (kWh/year) 
UNIT SALES PRICE 
12.5 4.2 12.5 4.2 
(yen/kWh) 
ANNUAL SALES PROFIT 
.Yen.28,665 
.Yen.10,127 
.Yen.38,792 
.Yen.37,223 
.Yen.2,563 
.Yen.39,786 
(yen/year) 
__________________________________________________________________________ 
Data in Table 2 are calculated on the basis of a reference value of an 
input of refuse 100 into the refuse incinerator to be 1 kg/h and according 
to the following conditions. 
Working days and stoppage days per year of the refuse incineration power 
generation plant are assumed to be 359 days and 6 days, respectively. 
Further, working days corresponding to the daytime zone of a weekday 
during which a unit purchase price for the electrical utility company to 
buy electricity from the refuse power generation plant is 12.5 yen per kWh 
are assumed to be 300 days per year, and working days corresponding to 
time zones on holidays or night hours of a weekday (hereinafter referred 
to as the other time zone) during which the foregoing unit purchase price 
of electricity is 4.2 yen per kWh are assumed to be 59 days per year. Day 
time hours of a day corresponding to the aforementioned daytime zone of a 
weekday are defined to include 14 hours from 8:00 to 22:00, and night time 
hours to include 10 hours from 22:00 to 8:00. Further, a calorific value 
of heat from refuse incineration is assumed to be 1800 kcal/kg. 
On the basis of reference values on electricity generated relative to a 
unit amount of steam indicated in Table 1, when refuse with a calorific 
value of 1800 kcal/kg is supplied at a ratio of 1 kg/h, electricity of 
0.546 kW is generated in each time zone of a daytime of a weekday and of 
the other time zone as well according to the conventional method, however, 
according to the invention, 0.709 kW of electricity is generated in 
daytime-of-a-weekday zone and 0.431 kW of electricity is generated in the 
other time zone on a holiday. 
Conventionally, in terms of annual operable hours for each time zone, 
average operable hours corresponding to the holiday.multidot.daytime zone 
are 300 days.times.14 hours=4200 hours, and average operable hours 
corresponding to the other time zone are (300 days.times.10 hours)+(59 
days.times.24 hours)=4416 hours. From these estimates and in consideration 
of each unit sales price for each time zone, it is calculated that annual 
sales profit for the weekday.multidot.daytime zone is under a high 
efficiency power generation operational condition .Yen.28,665 and the 
annual sales profit for the other time zone is .Yen.10,127, thereby adding 
up to .Yen.38,792 in total. 
On the other hand, according to the invention, annual operable hours for 
each time zone are estimated as follows. Operable hours corresponding to 
the weekday.multidot.daytime zone are 4200 hours which are the same as in 
the conventional example, and operable hours corresponding to the other 
time zone on holidays are 59 days.times.24 hours=1416 hours. That is, even 
thought we do not count 3000 hours (300 days.times.10 hours) for the 
weekday.multidot.night hour zone contribute to the generation of 
electricity, annual sales profit from sales of electricity to the electric 
utility company results in .Yen.37,223 in the weekday.daytime zone and 
.Yen.2,563 in the other time zone, thus adding up to .Yen.39,786 in total. 
That is, through implementation of the invention, annual sales profit from 
sales of surplus electricity for a unit amount of refuse incinerated at 1 
kg/h is increased as much as by .Yen.994 compared to the conventional 
case. Thereby, if there is provided a refuse incineration power generation 
plant which is capable of combusting, for example, 300 tons of refuse and 
waste per day (=12500 kg/h), an annual profit gain over .Yen.12,400,000 
(.Yen.994.times.12500 kg/h) will result in. 
Further, according to the embodiments as indicated in FIGS. 1 or 2, it is 
not necessary for the steam volume supplied through steam pipeline 112 to 
be constant. It can be arranged such that at flow control device 180 a 
predetermined amount of steam is branched from a total amount of steam 
generated to the steam turbine, and a surplus steam exceeding the 
predetermined amount is directed through pipeline 112 to the refrigerator 
5 or 5a. 
That is, fluctuation in the steam flow remaining in the steam pipeline 112 
appears as a fluctuation in a steam volume to be supplied to the 
absorption solution heater 52 in the refrigerator 5 or 5a, then, the 
foregoing fluctuation in the steam flow is caused to be absorbed in the 
absorption solution storage vessel 53. 
Thus, it becomes possible for the fluctuation in the amount of steam 
generated due to calorific variation of refuse 100 to be absorbed 
constantly in the steam pipeline system 112 according to the invention, 
and since a constant amount of steam can be supplied to the superheater 
portion of the exhaust heat recovery heat exchanger 11 and to the steam 
turbine 2 through the steam pipeline 110, the steam turbine can be 
operated stably. Thereby, such a loss of steam associated with the 
conventional method involved in adjusting the fluctuation in the steam 
generated by constantly discharging surplus volume outside its system can 
be completely eliminated. 
With reference to FIG. 3, still another embodiment of the invention will be 
described. Constituent components pertaining to refuse incineration and 
power generation are the same as in the preceding embodiment, except for 
refrigerator 5b of this embodiment which is further provided with means 
for concentrating a weak absorption solution by a hot combustion gas. 
According to this embodiment of the invention, exhaust gas from refuse 
combustion is directed through line 121 to absorption solution heater 52b 
of refrigerator 5b, then, after heating the absorption solution, the 
exhaust gas will be discharged through exhaust gas treatment equipment 
(not shown) and flue gas stack 122 to the atmosphere. Since the weak 
absorption solution can be concentrated by the aforementioned absorption 
solution heater 52b through this step, the steam which has been required 
in the preceding embodiment for the heat storage operation relating to the 
concentration of the absorption solution is no more required. Thereby, a 
total amount of steam to be generated by the exhaust heat recovery heat 
exchanger 11 in the refuse incinerator 1 can be reduced, and as a result, 
a total surface area required for heat transfer of the heat exchanger 11 
can be reduced. That is, a more compact size of equipment and a reduced 
cost for facilities can be achieved. Although it is not shown in the 
drawing, exhaust gas flow to the refrigerator can be regulated so as to be 
able to regulate heat storage operation (concentration of the absorption 
solution). According to this embodiment of the invention, since it is 
possible to utilize exhaust gas as a supplementary heat source in the 
refrigerator when the steam generated in the refuse incinerator 1 is not 
abundant, or even as a constant heat source therefor, a most efficient 
stable steam turbine operation can be ensured. 
With reference to FIG. 4, furthermore embodiment of the invention will be 
described. Main constituent components pertaining to the refuse 
incineration and the power generation are the same as in the preceding 
embodiments, except for refrigerator 5c in which a weak absorption 
solution is concentrated using a hot water at approximately 120.degree. C. 
According to this embodiment, heat is recovered from refuse incineration 
exhaust gas through hot water producing heat exchanger 12, and a hot water 
produced therein is directed through pipeline 131 to absorption solution 
heater 52c in refrigerator 5c to heat and concentrate a weak absorption 
solution therein. 
Thereby, it becomes possible to regulate at discretion the total volume of 
steam to be generated in exhaust heat recovery heat exchanger 11 in the 
refuse incinerator 1 as well as a total amount of hot water to be produced 
in the hot water producing heat exchanger 12, thereby, various modes of 
operation including individual operations for generating electricity and 
heat storage process, or parallel operation therebetween will be executed 
easily. Since this hot water can be utilized as a supplementary heat 
source in the refrigerator in case the steam generated in the refuse 
incinerator is insufficient by itself and cannot be spared, or even as a 
constant heat source in part therefor, a most efficient and stable steam 
turbine operation can be ensured. 
With reference to FIG. 5, a schematic pipeline diagram indicative of a 
still another embodiment of the invention will be described. Steam is 
supplied through steam line 112 into preheater 9 in which the steam 
exchanges heat with a condensate of steam having a relatively low 
temperature directed through condensate pipeline 410 from condenser 4. The 
condensate is heated in the preheater and directed through condensate 
pipelines 133, 130 to the exhaust heat recovery heat exchanger 11. On the 
other hand, the steam the calorific value of which is decreased due to 
heat exchange with the condensate is supplied through steam pipeline 120 
to absorption solution heating heat exchanger 52 in refrigerator 5, then 
after having heated the absorption solution, it is directed through 
pipelines 520 and 130 to the exhaust heat recovery heat exchanger 11. 
As having been described above, by heating the condensate to be returned to 
the exhaust heat recovery heat exchanger 11 of the refuse incinerator 1 
using the steam from the pipeline 112, it is possible to reduce a total 
calorific value required for steam production, thereby reducing a unit 
amount of refuse required for a unit electricity generation. That is, a 
more electricity can be generated from the same amount of refuse according 
to this embodiment of the invention. 
FIG. 6 is a schematic diagram depicting still another embodiment of the 
invention. 
Heat storage vessel 8a is provided for storing a portion of cold water 
which has been produced in absorption refrigerator 5. The cold water 
stored in the storage vessel 8a will be recovered on demand and returned 
through cold water pipelines 810, 811 for use as a cooling water in 
cooling piping 41 in the condenser 4. 
According to this embodiment of the invention indicated in the drawing of 
FIG. 6, since any type of absorption refrigerator with a conventional 
design and particulars can be used as the refrigerator 5, and what is 
stored is water, maintenance of this system is advantageously simple 
enough. 
With reference to FIG. 7 a schematic pipeline system of a still further 
embodiment of the invention is depicted. Cold water produced in 
refrigerator 5 is supplied through cold water pipeline 512 to facilities 
within and outside the refuse compound as a cold heat source for use in 
air-conditioning, and it is returned through cold water pipeline 513 after 
having done its work and been raised its temperature at customer's 
facilities. If a destination of the cold heat to be supplied through cold 
water piping 512 is to a district air-conditioning plant, cold heat 
production facilities by and large in this district can be reduced 
substantially, and at the same time consumption of electricity relating to 
air conditioning in this district can be significantly reduced as well. 
With reference to FIG. 8, a schematic flow diagram of still more embodiment 
of the invention will be described. In this embodiment, a portion of hot 
water after operating refrigerator 5 is branched from pipeline 520 to 
pipeline 521 to be supplied as heat source for use in air-conditioning to 
facilities within and outside the refuse incineration compound. Likewise 
as described above, if a destination of heat to be supplied through the 
pipeline 521 is to a district air-conditioning plant, heat production 
facilities for the district air-conditioning plant can be substantially 
reduced. 
Naturally, any such system combining the cold water supply line as depicted 
in FIG. 7 and the hot water supply line as depicted in FIG. 8 at the same 
time should be construed to be within the scope of the invention. 
According to any of the embodiments of the invention described hereinabove, 
since Rankine cycle power generation with an improved efficiency is 
possible, firstly, there is an advantage that a significant gain can be 
attained in the profit due to sales of electricity generated in the refuse 
incineration power generation plant. 
Secondly, since facilities pertaining to the refuse incinerator and those 
pertaining to the power generation are relatively easy to separate from 
each other, even when such an instance occurs that the power generation 
operation is difficult to maintain, for example, due to a failure in the 
power generation equipment or its inspection, the refuse incineration 
operation can be maintained stably without interruption. 
Further, if a particular time zone when a full-scale power generation 
operation is difficult to maintain falls within a capacity to allow a 
further heat storage (for example, within a capacity of the absorption 
solution storage vessel), most of the steam produced can be utilized for 
heat storage operation in the heat storage facility without discharging 
surplus steam out of the system, thereby there is such an advantage that 
no steam is wasted. 
Thirdly, since the fluctuation absorption function is provided to absorb 
the fluctuation in the steam production by the heat storage facility 
according to the invention, constant discharging of surplus steam to 
outside the system is no more necessary as followed in the conventional 
method, thereby there is such an advantage that a use ratio of the steam 
available through refuse incineration heat recovery can be improved 
significantly. 
Fourthly, there is another advantage that since it is possible to supply 
cold heat or hot water or both from the refuse incineration exhaust heat 
power generation plant to the other facilities including the district 
air-conditioning plant, substantial reductions in the heat production 
equipment in such district air-conditioning plant and in consumption of 
electricity at the customers' facilities can be achieved. Further, there 
is another advantage when the cold and hot heat sources are supplied to 
the customer on the commercial base that an increased profit in addition 
to the sales of electricity can be attained. 
By way of example, the refuse incineration exhaust heat power generation 
system has been described herein particularly as a preferred object to 
apply the embodiments of the invention, but it is not limited thereto, and 
it should be construed that various types of power generation systems 
having a heat engine based on a Rankine cycle including a combined power 
generation system which combines a gas turbine power generation system and 
a refuse incineration exhaust heat generation system are also within the 
scope of the invention. 
As have been described hereinabove, there has been provided the Rankine 
cycle power generation system capable of a stable and continuous operation 
of refuse incineration task, utilizing most effectively the incineration 
exhaust heat, and having an improved Ranking cycle efficiency.