JPH04342807A - Cogeneration exhaust heat recovery system - Google Patents

Abstract

PURPOSE:To lower the temperature of exhaust gas discharged into the atmosphere simultaneously with increasing the utilization factor of recovered waste heat by repeating the recovery of waste heat. CONSTITUTION:An air heater 3 serving as a secondary heat-exchanger is communicated with a waste heat boiler 2 serving as a primary heat-exchanger, downstream of the bolier 2, and air is induced into the air heater, thereby heated air having been heat-exchanged is fed to a heating zone (a).

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a cogeneration waste heat recovery system, and more specifically, to a cogeneration system that improves the heat recovery system for waste heat energy generated in a cogeneration system and further increases waste heat utilization efficiency. Regarding generation waste heat recovery system.

0002

[Prior Art] Currently, in cogeneration systems, for the purpose of utilizing waste heat, a waste heat boiler is installed in the exhaust gas system to recover high-temperature thermal energy from the exhaust gas, and the hot water and steam generated by this heat recovery are used. On the other hand, the exhaust gas after heat recovery is released directly into the atmosphere.

0003

[Problem to be solved by the invention] However, even with this waste heat energy released into the atmosphere after heat recovery,
They still generally have fairly high temperatures, for example on the order of 150-200°C. Therefore, it is currently not possible to say that heat recovery is being carried out sufficiently in terms of energy conservation. In addition, high-temperature exhaust gas emissions have become a new cause of thermal pollution. Particularly in cogeneration systems, the basic concept of cogeneration is to thoroughly recover and utilize waste heat that can be used in a cascade manner, and from this point of view, the current heat recovery described above is insufficient. I had a problem. The present invention was made in order to eliminate the above-mentioned drawbacks, and a heat exchanger is further installed downstream of the waste heat boiler that acts as a primary heat exchanger to re-recover the heat of high-temperature exhaust gas. The purpose of the present invention is to provide a cogeneration waste heat recovery system that increases waste heat utilization efficiency by supplying the obtained waste heat energy to, for example, district heating and cooling.

0004

[Means for Solving the Problems] That is, the above-mentioned object of the present invention is to provide an internal combustion engine, a waste heat boiler provided in the exhaust gas system of the engine, a heat exchanger provided downstream of the waste heat boiler, and an air A cogeneration system characterized by comprising: a duct system that introduces air into the heat exchanger and supplies it from the heat exchanger to a predetermined area; and a blower that is disposed in the duct system and blows air to the heat exchanger. Achieved by waste heat recovery system.

[0005]

[Function] For example, an air heater is installed downstream of the conventional waste heat boiler installed for exhaust heat recovery, and the heated air obtained by this heater is blown to the heating section. Therefore, energy saving can be improved. Furthermore, since the exhaust heat energy is sufficiently recovered and released into the atmosphere, thermal pollution can be reduced.

[0006]

Embodiments Hereinafter, embodiments of the cogeneration waste heat recovery system of the present invention will be explained in detail with reference to the drawings. One embodiment of FIG. 1 shows a configuration diagram when waste heat energy obtained by the present invention is used for heating. In the figure, this cogeneration exhaust heat recovery system is connected to an internal combustion engine 1 that constitutes the cogeneration system, and an exhaust gas pipe 5 that forms a part of the exhaust gas system of the internal combustion engine 1. A waste heat boiler 2, an air heater 3 connected to the latter part of the waste heat boiler 2 and serving as a heat exchanger via an exhaust gas pipe 6, which also forms an exhaust gas system, and an air heater 3 attached to the air heater 3 for discharging exhaust gas. A chimney 17 that discharges into the atmosphere, duct systems 7 and 8 that introduce air to the air heater 3 and supply heated air from the air heater 3 to a predetermined heating section a, and are arranged in the duct system 7. and a blower 4 for blowing air to the air heater 3.

To further describe the above configuration, the internal combustion engine 1 is for driving a generator 18 that generates electric energy, a heat pump that generates thermal energy, etc., and is composed of a diesel engine, a gas turbine, etc. There is. The duct system 7 that introduces air into the air heater 3 has an air intake side that communicates with the outside air intake port 12 and communicates with the outside air intake duct system 9 that is attached with the damper 14 and the return air intake port 13. and a return air intake duct system 10 with a damper 15 attached, and each of the duct systems 9, 10
The air-fuel mixture drawn in and adjusted is sent to the air heater 3 by the blower 4. Further, the heated air heat-converted by the air heater 3 passes through a duct system 8, and the duct system 8
Air is supplied into the heating section a from an air supply port 11 provided at the delivery end of the air. Note that the duct systems 7, 8
are connected via a bypass duct system 16 that bypasses the air heater 3 before the air heater 3. Also,
Although illustration and description are omitted in each duct system having the above configuration, it goes without saying that various valves, dampers, instruments, etc. may be appropriately provided depending on the purpose and scale of use. Further, the waste heat boiler 2 is provided with various water-based and steam-based devices for heat recovery depending on the purpose, as in the conventional structure.

In the cogeneration system equipped with the exhaust heat recovery system configured as described above, when the internal combustion engine 1 for power generation is operated, the exhaust gas discharged from the engine 1 has a high temperature of about 500°C. . This exhaust gas is sent to the waste heat boiler 3 via the exhaust gas pipe 5.
The heat is recovered and exchanged into hot water or steam. That is, up to this point the system is the same as the previous system. However, even the exhaust gas after heat recovery in the waste heat boiler 3 is still a high-temperature gas of more than 100 degrees Celsius, so the present invention further transfers this exhaust gas via the exhaust gas pipe 6 to the secondary heat exchanger. The air is supplied to the air heater 3. The air heater 3 heats the low-temperature air introduced by the blower 4 through the duct system 7 with the exhaust gas, and sends the heated air through the duct system 8 and the air supply port 11 to the heating section. a, and the space a
heating.

In this exhaust heat recovery system, an outside air intake duct system 9 and a return air intake 1 communicate with the outside air intake 12.
Each damper 1 attached to the return air duct system 10 communicating with 3
The opening degree of the blower 4 and 15 is adjusted as appropriate depending on the surrounding environment, return air temperature, heating conditions, etc.
supplies the mixed or unmixed gas obtained by adjustment to the air heater 3. On the other hand, if heating is not required during the interim period, etc.
The mixed air sent from the blower 4 passes through the bypass duct system 16 and duct system 8 that bypasses the air heater 3.
is supplied directly to heating section a. Therefore, in such a case, a duct system (not shown) is separately provided so that the heated air whose heat is recovered by the air heater can be supplied to, for example, a drying section and used for other purposes.

[0010] The exhaust gas, which has undergone heat exchange again in the air heater 3 as described above, is lowered in temperature and is discharged into the atmosphere through the chimney 17. Note that the exhaust gas temperature level varies depending on the type of fuel in the internal combustion engine 1, etc.
This will be appropriately considered depending on the type of exhaust gas, etc. In the above embodiment, an air heater is applied to the heat exchanger downstream of the waste heat boiler, and heated air is supplied to a predetermined section to heat the section. Instead, it is configured with at least one of a condenser, cooler, evaporator, or reboiler, and the heat medium is steam,
By using hot water, hot air, etc., it can also be configured to supply hot water, air conditioning, and heat to various facilities. In particular, in the configuration in the above embodiment, a condenser, which is a heat exchanger for a refrigerator, is installed in parallel with the air heater to reduce exhaust gas depending on the season, etc., in consideration of cases where heating is not required. It is also possible to provide a configuration in which mixed air is selectively supplied to the air heater and the condenser, and mixed air is introduced into the selected heat exchanger to perform heating and cooling of a predetermined section.

[0011]

[Effects of the Invention] As described above, according to the cogeneration waste heat recovery system of the present invention, the exhaust gas after passing through the waste heat boiler is recovered as waste heat and used for air conditioning, etc., so energy saving is greatly improved. The efficiency of the cogeneration system can be increased at the same time. Furthermore, since the temperature of the exhaust gas released into the atmosphere is lowered, thermal pollution in cities can be sufficiently reduced. Furthermore, by arranging heat exchangers such as waste heat boilers in multiple stages in the exhaust gas system, the exhaust gas is expanded and diffused in each stage. As a result, the sound energy is attenuated and muffled, resulting in an excellent muffling effect.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a cogeneration waste heat recovery system of the present invention.

[Explanation of symbols]

1 Internal combustion engine 2 Waste heat boiler 3 Air heater 4　Blower 5, 6 Exhaust gas pipe 7, 8 Duct system 9. Outside air intake duct system 10 Return air intake duct system 11 Air supply port 12 Outside air intake port 13 Return air intake port 14 Outside air intake duct system damper 15 Return air intake duct system damper 16 Bypass duct system 17 Chimney 18 Generator a Heating section

Claims (2)

[Claims] Claim 1: An internal combustion engine, a waste heat boiler provided in the exhaust gas system of the engine, a heat exchanger provided downstream of the waste heat boiler, and a method for introducing air into the heat exchanger and from the heat exchanger. A cogeneration waste heat recovery system comprising: a duct system for supplying air to a predetermined area; and a blower disposed in the duct system for blowing air to the heat exchanger. 2. A cogeneration waste heat recovery system, wherein the heat exchanger is constituted by at least one of an air heater, a condenser, a cooler, an evaporator, or a reboiler.