High-temperature heat storage and release internal combustion engine flue gas waste heat utilization method

Abstract

The invention relates to the field of internal combustion engine flue gas absorption, in particular to a high-temperature heat storage and release internal combustion engine flue gas waste heat utilization method which comprises the following steps: storing heat energy generated by an internal combustion engine; and the stored heat energy is distributed and utilized to adjust the temperature of the boiler inlet air and the boiler feed water, and the temperature fluctuation of the boiler inlet air and the boiler feed water is buffered. Through the high-temperature heat storage and release internal combustion engine flue gas waste heat utilization method, the waste heat utilization efficiency of an internal combustion engine system can be improved, and impact caused by the too high temperature of the internal combustion engine flue gas is relieved.

Description

Technical Field

[0001] The invention relates to the field of internal combustion engine smoke absorption, and in particular to a method for utilizing waste heat of internal combustion engine smoke with high-temperature heat storage and heat release. Background Art

[0002] The thermal efficiency of large-scale power generation internal combustion engines can reach 40% to 45%, but more energy is still discharged in the form of waste heat, including a large part of high-temperature exhaust gas with a temperature of 300 to 500°C. At present, there are generally two ways to deal with the high-temperature exhaust gas of internal combustion engines. One is that the internal combustion engine directly discharges the high-temperature flue gas into the atmosphere, which causes serious energy waste; the second is to add a waste heat boiler and a steam turbine power generation system at the tail of the internal combustion engine. However, due to the temperature of the exhaust gas of the internal combustion engine, the temperature of the steam generated by the waste heat boiler will not be too high, which leads to the low efficiency of the newly built waste heat power generation system, the high investment of the entire system, and the poor economic benefits.

[0003] For highly flexible power generation systems that couple coal-fired units with internal combustion engines, if the thermal system of the coal-fired units can be used to efficiently recover the waste heat of the internal combustion engines, it will play an important role in improving the overall efficiency of the system. However, due to the frequent and rapid load changes of the power generation internal combustion engines, the output fluctuations of their high-temperature flue gas waste heat are also large. If they are directly connected to the thermal system of the coal-fired units, it may cause an impact on the thermal system in a short period of time, affecting the safe and stable operation of the units. Summary of the invention

[0004] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide a method for utilizing waste heat from internal combustion engine flue gas with high temperature heat storage and heat release, which can solve the impact problem caused by direct connection of internal combustion engine flue gas to the thermal system of a coal-fired unit.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release, which includes storing the thermal energy generated by the internal combustion engine; allocating and utilizing the stored thermal energy to adjust the temperature of the boiler inlet air and boiler feed water, and buffering the temperature fluctuations of the boiler inlet air and boiler feed water.

[0007] As a preferred embodiment of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release as described in the present invention, storing the heat energy generated by the internal combustion engine includes: storing the heat energy of the internal combustion engine flue gas generated by the internal combustion engine through a high-temperature heat storage and heat release device; storing the heat energy of the internal combustion engine flue gas absorbed by the high-temperature heat storage and heat release device through a feed water heat exchanger; and discharging the internal combustion engine flue gas that has absorbed excess heat energy through the feed water heat exchanger.

[0008] As a preferred solution of the method for utilizing waste heat from flue gas of an internal combustion engine with high-temperature heat storage and heat release as described in the present invention, storing the heat energy generated by the internal combustion engine also includes directly absorbing the heat energy of the internal combustion engine by using boiler feed water.

[0009] As a preferred embodiment of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release as described in the present invention, utilizing the stored heat energy to adjust the temperature of the boiler inlet air includes: absorbing the heat energy stored in the high-temperature heat storage and heat release device through the boiler inlet air and transmitting it to the burner.

[0010] As a preferred embodiment of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release as described in the present invention, utilizing the stored heat energy to adjust the temperature of boiler feed water includes absorbing the heat energy stored in the feed water heat exchanger through boiler feed water and transmitting it to the coal-fired boiler.

[0011] As a preferred embodiment of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release as described in the present invention, the distributed stored heat energy includes: the temperature of the high-temperature flue gas before heat exchange is 350-400 degrees, and the temperature after heat exchange is 180 degrees; the temperature of the boiler inlet air before heat exchange is the ambient temperature (25 degrees), and after heat exchange is 130-150 degrees.

[0012] As a preferred solution of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release described in the present invention, the distributed stored heat energy includes: 60 degrees before the boiler feed water heat exchange and 90 degrees after the heat exchange.

[0013] As a preferred solution of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release described in the present invention, the distribution of stored heat energy also includes: the heat exchange ratio between boiler feed water and boiler inlet air is 1:2.

[0014] As a preferred embodiment of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release as described in the present invention, the temperature fluctuations of buffering boiler inlet air and boiler feed water include: the temperature fluctuation range of the boiler inlet air delivered to the burner is limited to within 10 degrees, and the temperature fluctuation range of the boiler feed water delivered to the coal-fired boiler is limited to within 5 degrees.

[0015] As a preferred solution of the method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release described in the present invention, the high-temperature heat storage and heat release device uses high-temperature ceramic heat storage materials to store energy.

[0016] The beneficial effects of the present invention are as follows: the method for utilizing waste heat of internal combustion engine flue gas with high-temperature heat storage and heat release described in the present invention can improve the waste heat utilization efficiency of the internal combustion engine system and alleviate the impact caused by the excessively high temperature of the internal combustion engine flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0018] Figure 1 The overall structural diagram of the method for utilizing waste heat from flue gas of an internal combustion engine with high-temperature heat storage and heat release is shown. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0022] Example 1

[0023] Reference Figure 1 , which is the first embodiment of the present invention, provides a method for utilizing waste heat from internal combustion engine flue gas with high-temperature heat storage and heat release, specifically including storing the thermal energy generated by the internal combustion engine 100; allocating and utilizing the stored thermal energy to adjust the temperature of the boiler inlet air and boiler feed water, and buffering the temperature fluctuations of the boiler inlet air and boiler feed water.

[0024] Furthermore, storing the heat energy generated by the internal combustion engine 100 includes: storing the heat energy of the internal combustion engine flue gas generated by the internal combustion engine 100 through the high-temperature heat storage radiator 200; storing the heat energy of the internal combustion engine flue gas absorbed by the high-temperature heat storage radiator 200 through the feed water heat exchanger 300; and discharging the internal combustion engine flue gas that has absorbed the heat energy through the feed water heat exchanger 300.

[0025] Furthermore, using the stored thermal energy to adjust the temperature of the boiler inlet air includes: absorbing the thermal energy stored in the high-temperature heat storage and radiator 200 through the boiler inlet air and transmitting it to the burner 500 .

[0026] Preferably, the temperature of the high-temperature flue gas before heat exchange is 350-400 degrees, and the temperature after heat exchange is 180 degrees; the temperature of the boiler inlet air before heat exchange is 25 degrees of the ambient temperature, and after heat exchange is 130-150 degrees.

[0027] It needs to be explained that the thermal efficiency of large-scale internal combustion engines can reach However, a considerable amount of energy is still discharged in the form of waste heat, including a large amount of heat At present, there are two main ways to deal with the high-temperature exhaust of internal combustion engines: the first is to discharge the high-temperature flue gas directly into the atmosphere, which leads to serious energy waste; the second method is to add a waste heat boiler and a steam turbine power generation system at the tail of the internal combustion engine, but due to the temperature of the exhaust gas of the internal combustion engine, the steam temperature generated by the waste heat boiler is relatively low, resulting in low efficiency of the newly built waste heat power generation system. At the same time, the investment in the entire system is high and the economic benefits are not good; for the highly flexible power generation system coupled with the coal-fired unit and the internal combustion engine, if the waste heat of the internal combustion engine can be efficiently recovered, it will play a vital role in improving the efficiency of the overall system. However, due to the frequent and rapid load changes of the power generation internal combustion engine, the output of the high-temperature flue gas waste heat fluctuates greatly. If it is directly connected to the thermal system of the coal-fired unit, it may cause an impact on the thermal system in a short period of time, thereby affecting the safety and stable operation of the unit.

[0028] In response to these problems, the present application proposes a method for utilizing the waste heat of internal combustion engine flue gas with high-temperature heat storage and heat release. Through multi-stage absorption of the internal combustion engine flue gas temperature by the high-temperature heat storage and heat release device 200 and the feed water heat exchanger 300, the thermal energy of the internal combustion engine flue gas can be fully absorbed and the temperature of the boiler inlet air can be buffered.

[0029] In this embodiment, in the system of the coal-fired unit coupled with the internal combustion engine, the high-temperature heat storage and heat release device 200 and the feedwater heat exchanger 300 are used to efficiently recover the waste heat of the flue gas of the internal combustion engine. After the optimized solution, 70-80% of the waste heat of the high-temperature flue gas of the internal combustion engine 100 can be recovered; this part of the waste heat of the high-temperature flue gas can make the internal combustion engine system generate 20% more additional electricity, avoiding the waste of energy and the impact of the direct emission of high-temperature flue gas on the surrounding environment, and greatly improving the energy utilization efficiency of the entire system. In addition, since the thermal system of the coal-fired unit is directly used to recover the waste heat of the high-temperature flue gas of the internal combustion engine 100, the structure of the entire system is very simple, the equipment investment and maintenance are very small, and the economic benefits are significant.

[0030] Example 2

[0031] Reference Figure 1 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0032] Furthermore, storing the heat energy generated by the internal combustion engine 100 also includes: using boiler feed water to directly absorb the heat energy of the internal combustion engine 100.

[0033] Furthermore, using the stored thermal energy to adjust the temperature of the boiler feed water includes: absorbing the thermal energy stored in the feed water heat exchanger 300 through the boiler feed water, and transmitting the thermal energy to the coal-fired boiler 400 .

[0034] Preferably, the boiler feed water temperature is 60 degrees before heat exchange and 90 degrees after heat exchange; the heat exchange ratio of boiler feed water to boiler inlet air is 1:2.

[0035] It should be noted that the working principle of the boiler involves combustion and heat exchange processes. The boiler heats water by burning fuel to generate steam or hot water for industrial or heating use. In this process, the heat exchange ratio of the boiler's feed water and air intake is 1:2, which can be explained from the following aspects:

[0036] Combustion process: The combustion of the boiler requires oxygen, and the main components of air are nitrogen and oxygen. In order to complete the combustion, more air is usually required than water to ensure sufficient oxygen supply.

[0037] Energy transfer: According to the laws of thermodynamics, the heat released by the boiler through combustion is mainly used to heat the feed water, and the incoming air needs to exchange heat with the heat exchanger. Therefore, air plays a very important role in the boiler, and its flow rate in the system generally maintains a certain ratio with the flow rate of water. In practical applications, the best heat exchange efficiency is often considered when designing the boiler, so that the heat exchange ratio between the incoming air and the feed water is 1:2.

[0038] Optimizing thermal efficiency: Setting the heat exchange ratio of feed water to air intake to 1:2 can improve the thermal efficiency of the boiler. This is because by properly adjusting the amount of air intake, the combustion efficiency can be maximized, energy waste can be reduced, and the overall economy and environmental protection of the boiler can be improved.

[0039] In summary, the heat exchange ratio of boiler feed water to inlet air is 1:2, which is based on comprehensive considerations of many factors such as the oxygen required for combustion, the effectiveness of heat transfer, and system optimization.

[0040] In this embodiment, by directly heating the boiler feed water through the internal combustion engine and heating the boiler feed water through the feed water heat exchanger 300, the boiler feed water temperature can be buffered, and the heat exchange ratio of the boiler feed water and the boiler inlet air can be adjusted as needed, thereby further improving the absorption efficiency of the thermal energy of the internal combustion engine flue gas.

[0041] It should be noted that since the high-temperature heat storage radiator 200 and the feed water heat exchanger 300 are added to the system of the coal-fired unit utilizing the waste heat of the internal combustion engine, the waste heat fluctuation of the high-temperature flue gas of the internal combustion engine 100 can be stored and released at an appropriate time by the high-temperature heat storage radiator 200 and the feed water heat exchanger 300 during the rapid load change process, which greatly reduces the impact of the fluctuation of the high-temperature flue gas of the internal combustion engine 100 on the thermal system and improves the safety and stability of the entire system. At the same time, the high-temperature heat storage radiator 200 and the feed water heat exchanger 300 can better regulate the heat entering the thermal system, respond to the requirements of rapid load changes of the coal-fired unit, and always keep the coal-fired unit running at a higher efficiency.

[0042] Example 3

[0043] Reference Figure 1 , which is the third embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0044] Specifically, buffering the temperature fluctuations of boiler inlet air and boiler feed water includes: limiting the temperature fluctuation range of boiler inlet air before being delivered to burner 500 to within 10 degrees, and limiting the temperature fluctuation range of boiler feed water before being delivered to coal-fired boiler 400 to within 5 degrees.

[0045] Furthermore, the high temperature heat storage and radiator 200 uses high temperature ceramic heat storage materials for energy storage.

[0046] Furthermore, high-temperature ceramic heat storage materials have high thermal stability in storing thermal energy: high-temperature ceramic materials can maintain their structure and performance at extremely high temperatures and are not easily deformed or degraded, so they are very suitable for high-temperature thermal energy storage systems; excellent thermal conductivity: many high-temperature ceramics have good thermal conductivity, can quickly absorb and release thermal energy, and improve the efficiency of thermal energy storage and conversion; corrosion resistance: high-temperature ceramic materials have good tolerance to many chemical environments and can be used for a long time under harsh conditions, thereby extending their service life; low thermal expansion coefficient: high-temperature ceramics usually have a lower thermal expansion coefficient, which means that the size changes little when the temperature changes, which can maintain the stability of the structure and is conducive to long-term storage of thermal energy.

[0047] In summary, the excellent performance of high-temperature ceramic heat storage materials has an excellent effect on buffering the temperature fluctuations of boiler inlet air and boiler feed water.

[0048] In this embodiment, by using high-temperature ceramic heat storage materials for energy storage, the temperature fluctuation range of the boiler inlet air delivered to the burner 500 can be limited to within 10 degrees, and the temperature fluctuation range of the boiler feed water delivered to the coal-fired boiler 400 can be limited to within 5 degrees, thereby greatly reducing the impact of the fluctuation of the high-temperature flue gas of the internal combustion engine 100 on the thermal system and improving the safety and stability of the entire system.

[0049] It should be noted that, through the high-temperature ceramic heat storage material in the high-temperature heat storage and radiator 200, part of the heat can be stored in the high-temperature ceramic heat storage material when the exhaust temperature of the internal combustion engine 100 is high or the flow rate is large, thereby reducing the heat absorption of the boiler inlet air; when the exhaust temperature of the internal combustion engine 100 decreases or the flow rate decreases, the high-temperature ceramic heat storage material releases additional heat to the boiler inlet air, thereby ensuring that the temperature of the boiler inlet air is within an appropriate range.

[0050] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only several embodiments are described in detail in this disclosure, it should be easily understood by the personnel referring to this disclosure that many modifications are possible (for example, the size, scale, structure, shape and ratio of various elements, and parameter values ​​(for example, temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of a plurality of parts or elements, the position of the element can be inverted or otherwise changed, and the property or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method step can be changed or reordered according to alternative embodiments. Therefore, the present invention is not limited to specific embodiments, but extends to a variety of modifications still falling within the scope of the appended claims.

[0051] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, the development effort will be a routine task of design, fabrication, and production without undue experimentation.

[0052] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release, characterized in that: include, storing heat energy generated by an internal combustion engine (100); Distribute and utilize the stored thermal energy to adjust the temperature of boiler inlet air and boiler feed water, and buffer the temperature fluctuations of boiler inlet air and boiler feed water.

2. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 1 is characterized in that: Storing heat energy generated by an internal combustion engine (100) comprises: storing heat energy of internal combustion engine flue gas generated by the internal combustion engine (100) through a high-temperature heat storage and heat release device (200); storing the heat energy of the internal combustion engine flue gas absorbed by the high-temperature heat storage and heat release device (200) through the feedwater heat exchanger (300); The internal combustion engine flue gas that has absorbed superheat energy through the feedwater heat exchanger (300) is discharged.

3. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 2 is characterized in that: Storing the thermal energy generated by the internal combustion engine (100) also includes: Boiler feed water is used to directly absorb the thermal energy of the internal combustion engine (100).

4. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 3 is characterized in that: Using stored thermal energy to regulate the temperature of boiler inlet air includes: The heat energy stored in the high-temperature heat storage and radiator (200) is absorbed by the boiler inlet air and transported to the burner (500).

5. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 4 is characterized in that: Using stored thermal energy to regulate boiler feed water temperature includes: The heat energy stored in the feed water heat exchanger (300) is absorbed by the boiler feed water and transported to the coal-fired boiler (400).

6. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 5 is characterized in that: Distributed stored thermal energy includes: The temperature of high-temperature flue gas before heat exchange is 350-400 degrees, and the temperature after heat exchange is 180 degrees; The temperature of the boiler air before heat exchange is the ambient temperature (25 degrees), and after heat exchange is 130-150 degrees.

7. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 6 is characterized in that: Distributed stored thermal energy includes: The boiler feed water temperature is 60 degrees before heat exchange and 90 degrees after heat exchange.

8. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 7 is characterized in that: Distributing stored heat also includes: The heat exchange ratio between boiler feed water and boiler inlet air is 1:

2.

9. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 8, characterized in that: Buffering boiler inlet air and boiler feed water temperature fluctuations includes: The temperature fluctuation range of the boiler inlet air before being delivered to the burner (500) is limited to within 10 degrees, and the temperature fluctuation range of the boiler feed water before being delivered to the coal-fired boiler (400) is limited to within 5 degrees.

10. The method for utilizing waste heat from flue gas of an internal combustion engine with high temperature heat storage and heat release according to claim 9, characterized in that: The high-temperature heat storage and radiator (200) uses high-temperature ceramic heat storage materials to store energy.

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