Waste incineration preheating device and waste incineration system

Abstract

The present invention discloses a waste incineration preheating device and a waste incineration system, wherein the waste incineration preheating device includes a hot air duct and a primary fan, a steam-air preheater, and a heat pipe heat exchanger arranged in sequence on the hot air duct along the gas flow direction. The heat pipe heat exchanger includes a heat exchanger body and a plurality of heat pipes. The heat pipes are provided with a phase change medium for heat exchange. The condensing pipe section at the upper end of the heat pipe is arranged in the condensing chamber of the heat exchanger body. The heating pipe section at the lower end of the heat pipe is located in the heating chamber of the heat exchanger body. The heating chamber is located in the flue. The heating pipe section is connected to the condensing pipe section, and both ends of the condensing pipe section are connected to the hot air duct. In the waste incineration preheating device provided in this application, a heat pipe heat exchanger is arranged downstream of the steam-air preheater. The heat source of the heat pipe heat exchanger comes from the gas in the flue, and high-quality steam is not consumed. As a result, the operating and use costs of the waste incineration preheating device provided in this application are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery, and in particular to a waste incineration preheating device. The present invention also relates to a waste incineration system comprising the waste incineration preheating device. Background Art

[0002] Compared to traditional fuels, garbage has high moisture content and low calorific value, requiring heating of the combustion air to ensure stable combustion. Generally, higher combustion air temperatures promote garbage drying, more complete combustion, and greater stability in the furnace temperature. Therefore, utilizing air preheating devices to raise the inlet air temperature is essential in waste incinerators.

[0003] Domestic waste incineration plants mostly use steam heating for air preheaters. The heating source comes from high-quality saturated steam and superheated steam, which increases steam consumption, reduces power generation, affects the economic benefits of the entire plant, and leads to higher operating costs for the waste incineration preheating equipment.

[0004] Therefore, how to reduce the use cost of the waste incineration preset device is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] An object of the present invention is to provide a waste incineration preheating device, which has a reduced operating cost. Another object of the present invention is to provide a waste incineration system comprising the waste incineration preheating device.

[0006] To achieve the above-mentioned objectives, the present invention provides a waste incineration preheating device, comprising a hot air duct and a primary fan, a steam-air preheater and a heat pipe heat exchanger sequentially arranged on the hot air duct along the gas flow direction. The heat pipe heat exchanger comprises a heat exchanger body and a plurality of heat pipes. A phase change medium for heat exchange is provided inside the heat pipe. The condensing pipe section at the upper end of the heat pipe is arranged in the condensing chamber of the heat exchanger body, and the heating pipe section at the lower end of the heat pipe is located in the heating chamber of the heat exchanger body. The heating chamber and the condensing chamber are separated and arranged. The heating chamber is located in the flue. The heating pipe section is connected to the condensing pipe section, and both ends of the condensing pipe section are connected to the hot air duct.

[0007] Preferably, the outer wall of the condensing pipe section is provided with heat dissipation fins, and the heating pipe section is a light pipe.

[0008] Preferably, the heat pipe heat exchanger is located in the flue at the middle end of the incineration boiler.

[0009] Preferably, along the flue gas flow direction, the heat pipe heat exchanger is located between the superheater and the economizer.

[0010] Preferably, a bypass pipe is further included, a bypass damper is provided on the bypass pipe, a main damper is provided on the hot air pipe between the steam-air preheater and the heat pipe heat exchanger, and the bypass pipe is arranged in parallel with the heat pipe heat exchanger and the main damper.

[0011] Preferably, it also includes a first temperature measuring instrument for measuring the temperature of the flue gas at the economizer outlet and a second temperature measuring instrument for measuring the temperature in the hot air duct downstream of the heat pipe heat exchanger.

[0012] Preferably, a control device is further included, and the main damper and the bypass damper are both electrically controlled dampers. The control device receives the temperature values ​​fed back by the first temperature measuring instrument and the second temperature measuring instrument to control the opening of the main damper and the bypass damper.

[0013] Preferably, it further comprises a soot blowing device arranged in the flue, and the soot blowing device blows gas toward the heating pipe section.

[0014] Preferably, a partition is provided in the heat exchanger body, the heat pipe includes multiple ones, the heat pipe is slidably sealed with the partition, the heating pipe section is located below the partition, the condensing pipe section is located above the partition, and the heat pipe can slide up and down along the partition.

[0015] A waste incineration system comprises an incineration boiler and a waste incineration preheating device connected to the incineration boiler, wherein the waste incineration preheating device is any one of the waste incineration preheating devices described above.

[0016] In the above technical solution, the waste incineration preheating device provided by the present invention includes a hot air duct and a primary fan, a steam-air preheater and a heat pipe heat exchanger arranged in sequence on the hot air duct along the gas flow direction. The heat pipe heat exchanger includes a heat exchanger body and several heat pipes. A phase change medium for heat exchange is provided inside the heat pipe. The condensing pipe section at the upper end of the heat pipe is arranged in the condensing chamber of the heat exchanger body, and the heating pipe section at the lower end of the heat pipe is located in the heating chamber of the heat exchanger body. The heating chamber is located in the flue, and the heating chamber and the condensing chamber are isolated from each other. The heating pipe section is connected to the condensing pipe section, and the condensing pipe section is connected to the hot air duct at both ends.

[0017] From the above description, it can be seen that in the waste incineration preheating device provided by the present application, a heat pipe heat exchanger is arranged downstream of the steam-air preheater. The heat source of the heat pipe heat exchanger comes from the gas in the flue, and high-quality steam is not consumed. Therefore, the operating and use costs of the waste incineration preheating device provided by the present application are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0019] Figure 1 A schematic structural diagram of a waste incineration preheating device provided by an embodiment of the present invention;

[0020] Figure 2 This is a schematic structural diagram of a heat pipe heat exchanger provided in an embodiment of the present invention.

[0021] in Figure 1-2 middle:

[0022] 1. Incineration boiler; 2. Evaporator; 3. Superheater;

[0023] 4. Heat pipe heat exchanger; 4-1. Heat exchanger body; 4-2. Heat dissipation fins; 4-3. Condensation pipe section; 4-4. Partition; 4-5. Heating pipe section; 4-6. Heat pipe;

[0024] 5. Economizer; 6. Primary fan; 7. Steam-air preheater; 8. Main damper; 9. Bypass damper; 10. Sootblowing device; 11. First temperature measuring instrument; 12. Second temperature measuring instrument; 13. Control device. DETAILED DESCRIPTION

[0025] The core of the present invention is to provide a waste incineration preheating device, which has a reduced use cost. Another core of the present invention is to provide a waste incineration system including the waste incineration preheating device.

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and implementation methods.

[0027] Please refer to Figure 1 and Figure 2 .

[0028] In a specific embodiment, the waste incineration preheating device provided by the specific embodiment of the present invention includes a hot air duct and a primary fan 6, a steam-air preheater 7 and a heat pipe heat exchanger 4 arranged in sequence on the hot air duct along the gas flow direction. The heat pipe heat exchanger 4 includes a heat exchanger body 4-1 and several heat pipes 4-6. A phase change medium is provided inside the heat pipe 4-6. The phase change medium stored in the heat pipe 4-6 for heat exchange is naphthalene, and the operating temperature range is between 250 and 350°C.

[0029] The condensing section 4-3 at the upper end of the heat pipe 4-6 is located within the heat exchanger housing, while the heating section 4-5 at the lower end of the heat pipe 4-6 is located within the flue. The heating section 4-5 is connected to the condensing section 4-3, and both ends of the heat exchanger housing are connected to the hot air duct. The condensing section 4-3 at the upper end of the heat pipe is located within the condensing chamber of the heat exchanger body 4-1, while the heating section 4-5 at the lower end of the heat pipe is located within the heating chamber of the heat exchanger body 4-1. The heating chamber and condensing chamber are separated. Preferably, the heating chamber and the flue chamber are shared. Alternatively, a filter mesh is provided on the side wall of the housing located within the flue to allow flue gas to pass through.

[0030] Specifically, each heat pipe 4-6 is preferably independently arranged and can be arranged in parallel with each other.

[0031] It can be seen from the above description that in the waste incineration preheating device provided in the present application, a heat pipe heat exchanger 4 is arranged downstream of the steam-air preheater 7. The heat source of the heat pipe heat exchanger 4 comes from the gas in the flue, and high-quality steam is not consumed. Therefore, the operating and use costs of the waste incineration preheating device provided in the present application are reduced.

[0032] This application does not consume drum saturated steam or main steam, which can effectively reduce steam consumption, achieve the purpose of energy saving and efficiency improvement, and increase the power generation efficiency of the incineration plant by 0.4%.

[0033] In one embodiment, the heat pipe 4-6 can be an integral bare pipe structure. To improve heat dissipation, the outer wall of the condenser section 4-3 is preferably provided with heat dissipation fins 4-2. Specifically, the heat dissipation fins 4-2 can be welded or bonded to the condenser section 4-3, and adjacent heat dissipation fins 4-2 can be arranged in parallel, or the heat dissipation fins 4-2 can be spirally wound around the outer side of the condenser section 4-3.

[0034] Preferably, the heat pipe heat exchanger 4 is located in the flue at the end of the incineration boiler 1. Specifically, when four flues are provided downstream of the incineration boiler 1, the heat pipe heat exchanger 4 is located in the fourth flue.

[0035] Specifically, along the flue gas flow path, heat pipe heat exchanger 4 is located between superheater 3 and economizer 5. The high-temperature flue gas generated by waste incineration exchanges heat with evaporator 2, superheater 3, heat pipe heat exchanger 4, and economizer 5 in sequence. Heat pipe heat exchanger 4, located between the boiler superheater 3 and economizer 5, can heat the primary air to a maximum temperature of 300°C, significantly enhancing the combustion of low-calorific-value waste.

[0036] like Figure 1 As shown, in a specific embodiment, the waste incineration preheating device also includes a bypass pipe, a bypass damper 9 is provided on the bypass pipe, a main damper 8 is provided on the hot air pipe between the steam-air preheater 7 and the heat pipe heat exchanger 4, and the bypass pipe is arranged in parallel with the channel formed by the heat pipe heat exchanger 4 and the main damper 8.

[0037] During operation, steam-air preheater 7 uses turbine exhaust to heat air to 140°C. Heat pipe heat exchanger 4 is connected to steam-air preheater 7 via a hot air duct. The hot air duct is equipped with a main damper 8 and a bypass damper 9. The combustion air temperature is adjusted by controlling the opening of main damper 8 and bypass damper 9. The heated primary air is then delivered to waste incineration boiler 1.

[0038] To ensure stable operation of the main incineration system, the waste incineration preheating device also includes a first temperature measuring instrument 11 for measuring the flue gas temperature at the economizer 5 outlet, and a second temperature measuring instrument 12 for measuring the temperature within the hot air duct downstream of the heat pipe heat exchanger 4. Specifically, the second temperature measuring instrument 12 is installed on the primary air inlet duct to monitor the flue gas temperature at the economizer 5 outlet and the primary air inlet temperature in real time. Specifically, personnel can adjust the opening and closing, as well as the degree of opening, of the bypass damper of the main damper 8 based on the values ​​of the first and second temperature measuring instruments 11 and 12.

[0039] In order to reduce the labor intensity of the staff, it is preferred that the waste incineration preheating device also includes a control device 13. The main damper 8 and the bypass damper 9 are both electrically controlled dampers. The control device 13 receives the temperature values ​​fed back by the first temperature measuring instrument 11 and the second temperature measuring instrument 12 to control the opening of the main damper 8 and the bypass damper 9. Specifically, the control device 13 is preferably a DCS system of the incineration plant. When the temperature of the primary air entering the furnace is lower than the design temperature, the opening of the main damper 8 is increased and the opening of the bypass damper 9 is reduced. To prevent low-temperature corrosion of the economizer 5, when the flue gas temperature at the economizer 5 outlet is lower than the preset temperature, for example, when the flue gas temperature at the economizer 5 outlet is lower than 180°C, the opening of the main damper 8 is reduced and the opening of the bypass damper 9 is increased.

[0040] The waste incineration preheating device also includes a sootblower 10 disposed within the flue to blow gas toward the heating pipe section 4-5. Specifically, sootblower 10 is provided before and after the heating pipe section 4-5 along the flue gas flow direction to reduce the degree of soot accumulation in the heating pipe section 4-5.

[0041] A partition 4-4 is provided within the heat exchanger body 4-1. Multiple heat pipes 4-6 are detachably mounted on the partition 4-4. The heating pipe section 4-5 is located below the partition 4-4, and the condensing pipe section 4-3 is located above the partition 4-4. The heat pipes 4-6 of the heat pipe heat exchanger are independently arranged, offering high removability and ease of maintenance and overhaul. The heat exchanger and furnace maintain a good seal, minimizing air leakage from the incineration boiler 1.

[0042] Specifically, the heat pipe is sealed against a partition, with the heating section located below the partition and the condensing section above. The heat pipe can slide up and down along the partition. By sliding the heat pipe, the length of the heating and condensing sections on the heat pipe can be adjusted, thereby adjusting the relative areas of the heating and condensing sections on a single heating pipe. For example, if the wall temperature of a heat pipe is low, the area of ​​the heating section can be increased, while the area of ​​the condensing section can be reduced, thereby increasing the wall temperature of the heat pipe.

[0043] Specifically, the areas of the heating pipe section and the condensing pipe section can be manually adjusted to ensure that the wall temperature of each heat pipe is higher than the dew point temperature to prevent dew point corrosion.

[0044] During actual use, a clip for fixing the heat pipe is provided in the heat exchanger body. When the heat pipe is adjusted to a preset position, the heat pipe is fixed by the clip. The clip can be set on the partition or the inner wall of the heat exchanger body.

[0045] During operation, the waste incineration preheating unit delivers 50,200 Nm³ / h of primary air at 20°C (1.4 MPa, 294°C) via primary fan 6 to steam-air preheater 7 (extraction parameters: 140°C). There, 18,600 Nm³ / h of primary air is delivered to heat pipe heat exchanger 4 and heated to 300°C. Another 31,600 Nm³ / h of primary air enters the bypass airflow, and the combined primary air reaches a temperature of 200°C before entering the furnace. The waste incineration generates 82,028 Nm³ / h of flue gas, with temperatures of 678°C at the inlet of evaporator 2, 581°C at the inlet of superheater 3, 353°C at the inlet of heat pipe heat exchanger 4, 320°C at the inlet of economizer 5, and 190°C at the outlet. The boiler's evaporation capacity reaches 46.9 t / h, increasing power generation by 0.4%.

[0046] Specifically, the relevant thermal parameters of the embodiment of the present application are shown in Table 1.

[0047]

[0048] Table 1 Thermal parameters related to the embodiment

[0049] The present application provides a waste incineration system comprising an incineration boiler 1 and a waste incineration preheating device connected to the incineration boiler 1, wherein the waste incineration preheating device is any of the waste incineration preheating devices described above. The specific structure of the waste incineration preheating device is described above, and the present application includes the above-mentioned waste incineration preheating device and also has the above-mentioned technical effects.

[0050] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0051] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waste incineration preheating device, characterized in that: The invention comprises a hot air duct and a primary fan, a steam-air preheater and a heat pipe heat exchanger sequentially arranged on the hot air duct along the gas flow direction. The heat pipe heat exchanger comprises a heat exchanger body and a plurality of heat pipes. A phase change medium for heat exchange is provided inside the heat pipe, and the phase change medium is naphthalene. The operating temperature range is between 250°C and 350°C. The condensing pipe section at the upper end of the heat pipe is arranged in the condensing chamber of the heat exchanger body, and the heating pipe section at the lower end of the heat pipe is located in the heating chamber of the heat exchanger body. The heating chamber and the condensing chamber are separated and arranged. The heating chamber is located in the flue. The heating pipe section is connected to the condensing pipe section, and both ends of the condensing pipe section are connected to the hot air duct. The outer wall of the condensing pipe section is provided with heat dissipation fins, and the heating pipe section is a light pipe; The heating chamber and the condensing chamber are separated and arranged, and the heating chamber is shared with the flue cavity; Along the flue gas flow direction, the heat pipe heat exchanger is located between the superheater and the economizer; The heat pipes include multiple ones, and a partition is provided in the heat exchanger body. The heat pipes are slidably sealed with the partition. The heating pipe section is located below the partition, and the condensing pipe section is located above the partition. The heat pipes can slide up and down along the partition. By sliding the heat pipes, the lengths of the heating pipe sections and the condensing pipe sections on the heat pipes can be adjusted, thereby adjusting the relative areas of the heating pipe sections and the condensing pipe sections on a single heat pipe.

2. The waste incineration preheating device according to claim 1, characterized in that: The heat pipe heat exchanger is located in the flue at the middle end of the incineration boiler.

3. The waste incineration preheating device according to claim 2, characterized in that: It also includes a bypass pipe, which is provided with a bypass damper. The hot air pipe between the steam-air preheater and the heat pipe heat exchanger is provided with a main damper. The bypass pipe is arranged in parallel with the channel formed by the heat pipe heat exchanger and the main damper.

4. The waste incineration preheating device according to claim 3, characterized in that: It also includes a first temperature measuring instrument for measuring the temperature of the flue gas at the economizer outlet and a second temperature measuring instrument for measuring the temperature in the hot air duct downstream of the heat pipe heat exchanger.

5. The waste incineration preheating device according to claim 4, characterized in that: It also includes a control device, wherein the main damper and the bypass damper are both electrically controlled dampers, and the control device receives the temperature values ​​fed back by the first temperature measuring instrument and the second temperature measuring instrument to control the opening of the main damper and the bypass damper.

6. The waste incineration preheating device according to claim 1, characterized in that: It also includes a soot blowing device arranged in the flue, and the soot blowing device blows gas toward the heating pipe section.

7. A waste incineration system, comprising an incineration boiler and a waste incineration preheating device connected to the incineration boiler, characterized in that: The waste incineration preheating device is the waste incineration preheating device according to any one of claims 1 to 6.

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