A waste heat boiler layout structure for burning high calorific value garbage

Abstract

The present invention discloses a waste heat boiler arrangement structure for burning high calorific value garbage, comprising an incineration furnace and a first flue, a second flue and a third flue connected in sequence along the flue gas flow direction, wherein a high-temperature heating surface is arranged in the first flue, a water-cooled evaporation screen and a low-temperature heating surface are arranged in sequence along the flue gas flow direction in the second flue, and an economizer is arranged in the third flue. The present invention can realize a waste heat boiler arrangement structure for burning high calorific value garbage, and compared with the existing scheme, the system has the advantages of small footprint, light boiler weight, high heat transfer temperature and pressure, and sufficient convection area temperature and pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat boilers burning high calorific value garbage, and more specifically, to a waste heat boiler arrangement structure burning garbage with a calorific value of more than 10MJ / kg. Background Art

[0002] At present, the design calorific value of domestic waste power plants is generally between 6MJ / kg and 8MJ / kg. With the popularization of waste classification policies and the further improvement of people's living standards, the calorific value of urban domestic waste will inevitably show an upward trend year by year. At present, some developed countries in Europe and the United States, such as Denmark, Germany, and the United States, generally have a design fuel calorific value of 11MJ / kg or above for waste power plants. It can be predicted that in a few years, the design calorific value of domestic urban domestic waste will reach or exceed 10MJ / kg, and the proportion of high calorific value waste will increase year by year.

[0003] At the same time, as waste-to-energy technology, especially high-temperature corrosion resistance technology, becomes increasingly mature, the steam parameter selection of waste heat boilers is also increasingly developing towards high parameters, from the early medium temperature and medium pressure (4MPa, 400℃) to the currently popular medium temperature and sub-high pressure (6.4MPa, 450℃). The steam parameters of some planned projects in China have even reached sub-high temperature and high pressure parameters (9.8MPa, 485℃). In addition, the introduction of a heating system into the waste heat boiler is conducive to improving the power of the steam turbine, and is expected to increase the efficiency of the entire plant by about 4%. The economy is very considerable. Waste heat boilers with primary reheating are also one of the current hot spots and are receiving more and more attention from power plants.

[0004] The existing conventional waste heat boiler scheme generally adopts a four-flue or five-flue structure, that is, one or two empty flues + three flue convection heat exchange + four flue economizers (vertical arrangement) or one or two or three empty flues + horizontal flue convection heat exchange + economizer flue (horizontal arrangement), with a complex overall layout and loose structure. In order to control high-temperature corrosion, the inlet flue temperature is usually required to be controlled within 600℃. On the other hand, in order to meet environmental protection standards, it is required to ensure that the flue gas stays in the area above 850℃ in the first flue for no less than 2S under various working conditions. Refractory castables are laid in most areas of the first flue water-cooled wall, and the first flue area absorbs very little heat to meet the residence time requirements.

[0005] For the future waste heat furnace system with high calorific value (greater than 10MJ / kg), high parameters (main steam 6.4MPa, 450℃ and above) and one-time reheating, the existing conventional layout scheme cannot meet the requirements. The main reasons are: First, with the increase of main steam parameters, the working medium temperature of superheater and reheater inlet increases (for example, 9.8MPa corresponds to superheater inlet temperature of 309℃). Under the premise of ensuring that the superheater inlet flue gas temperature is controlled within 600℃, the heat exchange temperature and pressure of the convective heat exchange area, especially the low flue gas temperature area, are very limited. It is necessary to pile up a large amount of superheater (reheater, if any) area to meet the heat transfer needs, resulting in superheater redundancy. The weight of the boiler and the investment cost increase significantly; secondly, for the reheat unit, due to the simultaneous existence of superheater heat absorption and reheater heat absorption, the total heat absorption required on the working medium side of the convection area increases significantly, while the maximum heat release on the flue gas side (from 600°C to the saturated steam temperature of the drum) is a certain value. As the steam parameters increase, the maximum heat release on the flue gas side will be less than the heat absorption required on the working medium side, making it difficult to arrange the heating surface of the waste heat furnace; thirdly, for high calorific value garbage, its theoretical combustion temperature is above 1200°C, and the requirements of 850°C and 2S can be met if one flue has a certain amount of heat absorption. However, the first flue of the existing scheme absorbs very little heat, resulting in a waste of heat exchange temperature and pressure in the high flue temperature area.

[0006] The solutions in the prior art either fail to mention how to increase the heat exchange temperature and pressure in the superheater (reheater, if any) area, or fail to mention how to solve the difficulty in arranging the heating surface caused by the maximum heat release in the convection area being less than the required heat absorption, or fail to consider in detail how to arrange the waste heat boiler burning high calorific value garbage. In other words, they all fail to solve the core problem - how to increase the heat exchange temperature and pressure in the superheater and reheater (if any) area when burning high calorific value garbage, how to ensure that the maximum heat release in the convection area is greater than the required heat absorption, and how to effectively utilize the heat exchange temperature and pressure in the high smoke temperature area of ​​the first flue on the basis of ensuring the residence time. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention proposes a waste heat boiler arrangement structure capable of burning high calorific value garbage.

[0008] The present invention provides a waste heat boiler arrangement structure for burning high calorific value garbage, comprising an incineration furnace and a first flue, a second flue and a third flue connected in sequence along the direction of flue gas flow, a high-temperature heating surface being arranged in the first flue, a water-cooled evaporation screen and a low-temperature heating surface being arranged in sequence along the direction of flue gas flow in the second flue, and an economizer being arranged in the third flue.

[0009] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the first flue is a water-cooled flue, the second flue is a water-cooled flue, and the third flue is a water-cooled flue, a steam-cooled flue, or a combination of water-cooled and steam-cooled flue.

[0010] According to an embodiment of the arrangement structure of a waste heat boiler for burning high calorific value garbage of the present invention, the high-temperature heating surface is arranged in the middle of the first flue and is arranged in a co-current arrangement; the water-cooled evaporation screen adopts a screen structure and includes upper and lower headers and a water-cooled tube bundle, and the water-cooled evaporation screen and the low-temperature heating surface are arranged in a counter-current arrangement.

[0011] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the high temperature heating surface adopts a serpentine tube structure and the header of the high temperature heating surface is arranged outside the first flue near the front side of the incineration furnace, and the tube wall surface of the high temperature heating surface is provided with anti-corrosion material.

[0012] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the high-temperature stage heating surface includes at least a high-temperature stage superheater and may also include a high-temperature stage reheater; the low-temperature stage heating surface includes at least a low-temperature stage superheater and may also include a low-temperature stage reheater.

[0013] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the low-temperature heating surface that cannot be arranged in the second flue is arranged upstream of the economizer in the third flue, and the second flue or the third flue is also arranged with an evaporator arranged upstream or downstream of the low-temperature heating surface.

[0014] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the waste heat boiler arrangement structure also includes an air preheating unit and a feed water heating unit. The feed water heating unit utilizes saturated steam from the boiler drum to heat part of the feed water sent to the economizer, and the air preheating unit extracts steam from the boiler drum and the steam turbine and preheats the primary air and the secondary air.

[0015] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the flue gas flow of the waste heat boiler arrangement structure is: the high-temperature flue gas generated by the combustion of garbage in the incineration furnace flows through the first flue, the second flue and the third flue in sequence and is led out through the economizer outlet into the flue gas purification system.

[0016] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, the outlet flue gas temperature of the first flue is controlled at 800℃~850℃, the outlet flue gas temperature of the water-cooled evaporation screen is controlled at 500℃~650℃, the outlet flue gas temperature of the second flue is controlled at 300℃~400℃, and the outlet flue gas temperature of the third flue is controlled at 180℃~220℃.

[0017] According to an embodiment of the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention, when the high-temperature stage heating surface and the low-temperature stage heating surface do not include the high-temperature stage reheater and the low-temperature stage reheater, the steam-water flow of the waste heat boiler arrangement structure is as follows: the feed water is first introduced into the economizer, and then introduced into the boiler drum through the connecting pipe, the boiler water of the boiler drum is respectively sent to the first flue, the second flue, the third flue and the water-cooled evaporation screen to exchange heat with the flue gas, the saturated steam of the boiler drum is introduced into the low-temperature stage superheater through the connecting pipe, and then flows through the high-temperature stage superheater, and is introduced from the outlet of the high-temperature stage superheater to the high-pressure cylinder of the steam turbine to perform work;

[0018] When the high-temperature stage heating surface and the low-temperature stage heating surface include a high-temperature stage reheater and a low-temperature stage reheater, the steam-water flow on the reheat steam side in the waste heat boiler arrangement structure is as follows: the reheated steam is introduced from the turbine side and sent to the low-temperature stage reheater, flows through the high-temperature stage reheater, is led out from the high-temperature stage reheater outlet, and is then sent to the low-pressure cylinder of the turbine to perform work.

[0019] Compared with conventional solutions, the overall heat exchange temperature and pressure of the superheater and reheater (if any) in the waste heat boiler arrangement structure for burning high calorific value garbage of the present invention is large, which can greatly reduce the required heat exchange area, and at the same time can ensure that the maximum heat release in the convection area is greater than the required heat absorption. In addition, the first flue area is provided with a part of the heating surface, taking into account a certain amount of heat absorption, and effectively utilizing the heat exchange temperature and pressure of the high flue temperature area. In particular, the waste heat boiler of this structure is composed of three flues as a whole, which saves one or two flues compared with the existing solution, and the overall layout of the system is compact and the structure is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of an arrangement structure of a waste heat boiler for burning high calorific value garbage according to an exemplary embodiment of the present invention is shown.

[0021] Figure 2 A structural schematic diagram of an arrangement structure of a waste heat boiler for burning high calorific value garbage according to another exemplary embodiment of the present invention is shown.

[0022] Description of reference numerals:

[0023] 1-incineration furnace, 2-first flue, 3-second flue, 4-third flue, 5-economizer outlet, 6-high-temperature heating surface, 7-water-cooled evaporation screen, 8-low-temperature heating surface, 9-economizer, 10-boiler drum. DETAILED DESCRIPTION

[0024] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0025] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0026] The following is a detailed description of the arrangement structure of the waste heat boiler for burning high calorific value garbage of the present invention.

[0027] Figure 1 A schematic diagram showing the structural arrangement of a waste heat boiler for burning high calorific value garbage according to an exemplary embodiment of the present invention is shown. Figure 2 A structural schematic diagram of an arrangement structure of a waste heat boiler for burning high calorific value garbage according to another exemplary embodiment of the present invention is shown.

[0028] like Figure 1 and Figure 2 As shown, according to an exemplary embodiment of the present invention, the waste heat boiler arrangement structure for burning high calorific value garbage includes an incineration furnace 1 and a first flue 2, a second flue 3 and a third flue 4 connected in sequence along the direction of flue gas flow, wherein a high-temperature heating surface 6 is arranged in the first flue 2, a water-cooled evaporation screen 7 and a low-temperature heating surface 8 are arranged in sequence along the direction of flue gas flow in the second flue 3, and an economizer 9 is arranged in the third flue 4.

[0029] Since the theoretical combustion temperature of high calorific value (greater than 10MJ / kg) garbage is above 1200°C, the requirement of 2S above 850°C can be met by arranging an appropriate amount of heating surface in the first flue 2. The present invention arranges a high-temperature heating surface 6 in the first flue 2 area, effectively utilizing the heat exchange temperature and pressure in the high flue temperature area, greatly reducing the required heat exchange area.

[0030] Preferably, the high-temperature heating surface includes at least a high-temperature superheater, and of course, a high-temperature reheater. The high-temperature heating surface 6 is arranged in the middle of the first flue 2 and is arranged downstream, which can take into account both a lower high-temperature corrosion rate and a higher heat transfer temperature and pressure. If the position is too low, the flue gas temperature is too high and the high-temperature corrosion rate is accelerated. If the position is too high, the heat transfer temperature and pressure are reduced, and the required heat exchange area is increased.

[0031] The first flue 2 is a water-cooled flue, the high-temperature heating surface 6 preferably adopts a serpentine structure, and the header of the high-temperature heating surface is arranged outside the first flue 2 near the front side of the incineration furnace 1. In addition, the outlet flue gas temperature of the first flue 2 is preferably controlled at 800°C to 850°C.

[0032] In order to control high-temperature corrosion, necessary anti-corrosion measures need to be considered for the surface of the tube wall of the high-temperature heating surface 6 in the first flue 2 area, such as setting anti-corrosion materials, for example, selecting high-temperature resistant and corrosion-resistant metals or non-metallic materials, thereby isolating the direct contact between the tube wall and the flue gas and extending the service life of the high-temperature heating surface.

[0033] The second flue 3 is also a water-cooled flue, in which a water-cooled evaporation screen 7 and a low-temperature heating surface 8 are arranged. The water-cooled evaporation screen 7 adopts a screen structure and includes upper and lower headers and a water-cooled tube bundle. The water-cooled evaporation screen and the low-temperature heating surface are preferably arranged in a countercurrent arrangement to improve the heat exchange efficiency. Similarly, the low-temperature heating surface 8 includes at least a low-temperature superheater and may also include a low-temperature reheater. The low-temperature superheater may include a low-temperature superheater and a medium-temperature superheater.

[0034] In order to control high temperature corrosion in the downstream area, the outlet flue gas temperature of the water-cooled evaporation screen 7 should be controlled at 500°C to 650°C, and the outlet flue gas temperature of the second flue should be controlled at 300°C to 400°C.

[0035] Compared with the high-temperature heating surface, the temperature of the working fluid side of the low-temperature heating surface is relatively low, and the actual operating wall temperature is also low. The calculated wall temperature in this area usually does not exceed 400°C, and the temperature on the flue gas side does not exceed 650°C. Therefore, there is no need to consider anti-corrosion measures for the tube wall of the low-temperature heating surface. In addition, since the high-temperature heating surface is moved to the first flue, the actual total heat absorption required on the working fluid side of the low-temperature heating surface forward heat exchange area is greatly reduced, which can ensure that the maximum heat release in this area is greater than the required heat absorption. In addition, the inlet flue gas temperature in this area is slightly higher than that of the conventional solution, while the temperature on the working fluid side is lower than that of the conventional solution, and the heat exchange temperature and pressure are greater than that of the conventional solution, which can effectively reduce the heat exchange area required for the low-temperature heating surface.

[0036] The third flue 4 can be a water-cooled flue, a steam-cooled flue or a combination of water-cooled and steam-cooled flue, wherein an economizer 9 is arranged to further reduce the flue gas temperature, and the flue gas temperature at the economizer outlet or the third flue outlet is preferably controlled at 180° C. to 220° C. The economizer can be set to multiple stages.

[0037] In addition, the low-temperature heating surface 6 that cannot be arranged in the second flue 3 due to space limitations can also be arranged upstream of the economizer in the third flue. In addition, the second flue 3 or the third flue 4 can also be arranged with an evaporator (not shown) arranged upstream or downstream of the low-temperature heating surface to further enhance the cooling effect.

[0038] By adjusting the above arrangement, on the one hand, the heat exchange area can be reduced, and on the other hand, it can ensure that the maximum heat release of the convective heat exchange area is greater than the required heat absorption. At the same time, the high-temperature heating surface is moved to the first flue and necessary anti-corrosion measures are considered. While meeting the flue gas residence time, the heat exchange temperature and pressure of the high flue temperature zone are effectively utilized, and high-temperature corrosion is controllable.

[0039] In addition, the waste heat boiler arrangement structure of the present invention also includes an air preheating unit (not shown) and a feed water heating unit (not shown). The feed water heating unit uses saturated steam from the drum 10 to heat part of the feed water sent to the economizer 9, preventing low-temperature corrosion of the economizer while ensuring that the exhaust gas temperature meets the requirements of the flue gas purification system; the air preheating unit extracts steam from the drum 10 and the steam turbine and preheats the primary air and secondary air. Among them, the drum 10 heats the drainage from the economizer 9 and provides it to the water-cooled heating surface in each flue.

[0040] Therefore, the flue gas flow of the waste heat boiler arrangement structure in the present invention is: the high-temperature flue gas generated by the combustion of garbage in the incineration furnace 1 flows through the first flue 2, the second flue 3 and the third flue 4 in sequence and is led out through the outlet of the economizer 9 into the flue gas purification system (not shown).

[0041] Furthermore, when the high-temperature heating surface 6 and the low-temperature heating surface 8 do not include the high-temperature reheater and the low-temperature reheater, the steam-water flow of the waste heat boiler arrangement structure in the present invention is as follows: the feed water is first introduced into the economizer 9, and then introduced to the drum 10 through the connecting pipe, the boiler water of the drum 10 is respectively sent to the first flue 2, the second flue 3, the third flue 4 and the water-cooled evaporation screen 7 and the evaporator (if any) to exchange heat with the flue gas, the saturated steam of the drum 10 is introduced to the low-temperature superheater 8 through the connecting pipe, and then flows through the high-temperature superheater 6, and is led out from the outlet of the high-temperature superheater 6 to the high-pressure cylinder of the steam turbine to do work.

[0042] When the high-temperature stage heating surface and the low-temperature stage heating surface include a high-temperature stage reheater and a low-temperature stage reheater, the steam-water flow on the reheat steam side in the waste heat boiler arrangement structure of the present invention is as follows: the reheated steam is introduced from the turbine side and sent to the low-temperature stage reheater, flows through the high-temperature stage reheater, is led out from the high-temperature stage reheater outlet, and is then sent to the low-pressure cylinder of the turbine to perform work.

[0043] Based on this, the present invention is particularly suitable for the treatment of high calorific value garbage. The whole system consists of three flues, which saves one or two flues compared with conventional solutions. The overall layout is compact, saving land and investment costs.

[0044] The present invention will be further described below in conjunction with the embodiments.

[0045] Embodiment 1:

[0046] The fuel designed in this embodiment is domestic waste. The fuel composition is shown in Table 1. Its lower calorific value is 11000 kj / kg. The waste processing capacity is 400 t / d. The boiler design parameters are shown in Table 2 below.

[0047] Table 1 Design fuel composition of Example 1

[0048]

[0049]

[0050] Table 2 Boiler parameters of Example 1

[0051] name unit 100% BMCR Main steam flow t / h 54.4 Main steam outlet pressure MPa(g) 13.8 Main steam outlet temperature ℃ 510 Reheat steam flow t / h 44.4 Reheat steam inlet pressure MPa(g) 2.66 Reheat steam outlet pressure MPa(g) 2.49 Reheat steam inlet temperature ℃ 330 Reheat steam outlet temperature ℃ 495 Feed water temperature ℃ 130 Theoretical combustion temperature ℃ 1252

[0052] Combine the following Figure 1 The technical solution of this embodiment is described.

[0053] The waste heat boiler is a single drum boiler with natural circulation, one-time intermediate reheating and incineration grate combustion. The garbage is fed from the feed port and burned in the incineration furnace 1. The high-temperature flue gas generated flows through the first flue 2, the second flue 3, and the third flue 4 in sequence, and is led out through the economizer outlet 5 and enters the flue gas purification system.

[0054] A high-temperature heating surface 6 is arranged in the first flue 2. Specifically, a high-temperature superheater and a high-temperature reheater are arranged in sequence along the flue gas flow direction, and the high-temperature heating surfaces are all arranged downstream.

[0055] A water-cooled evaporator screen 7 and a low-temperature heating surface 8 are arranged in the second flue 3. Specifically, a water-cooled evaporator screen, a medium-temperature superheater, a low-temperature superheater, and a low-temperature reheater are arranged in sequence along the flue gas flow direction, and the water-cooled evaporator screen and the low-temperature heating surface are both arranged in countercurrent.

[0056] An evaporator and an economizer are arranged in the third flue 4. Specifically, the evaporator, economizer 1, economizer 2, and economizer 3 are arranged in sequence along the flow direction of the flue gas, and the evaporator and economizer are arranged in countercurrent.

[0057] The surface of the high-temperature grade heating surface 6 pipe wall is clad with high-temperature resistant and corrosion-resistant nickel-based alloy, and the designed cladding thickness is 2.5mm.

[0058] The flue gas temperatures in each area under the design conditions are as follows: the flue gas temperature at the outlet of the first flue 2 is 820°C, the flue gas temperature at the outlet of the water-cooled evaporator 11 is 630°C, the flue gas temperature at the outlet of the second flue 3 is 330°C, and the boiler design exhaust temperature (the flue gas temperature at the outlet of the third flue) is 190°C.

[0059] Embodiment 2:

[0060] The fuel designed in this embodiment is domestic waste, the fuel composition is shown in Table 3, the lower calorific value is 10000 kj / kg, the waste processing capacity is 300 t / d, and the boiler design parameters are shown in Table 2 below.

[0061] Table 3 Design fuel composition of Example 2

[0062]

[0063] Table 4 Boiler parameters of Example 2

[0064]

[0065]

[0066] Combine the following Figure 2 The technical solution of this embodiment is described.

[0067] The waste heat boiler is a single drum, natural circulation, incineration grate combustion mode. The difference between this embodiment and embodiment 1 is that this embodiment does not contain a reheating system, the garbage design calorific value and garbage capacity are slightly different, and the main heating surface layout is adjusted accordingly.

[0068] A high-temperature heating surface 6 is arranged in the first flue 2. Specifically, a high-temperature superheater is arranged in the middle of the first flue 2, and the designed thickness of the surfacing is 2 mm.

[0069] A water-cooled evaporation screen 7 and a low-temperature heating surface 8 are arranged in the second flue 3. Specifically, a water-cooled evaporation screen, a medium-temperature superheater, a low-temperature superheater and an evaporator are arranged in sequence along the flue gas flow direction.

[0070] Economizers are arranged in the third flue 4, specifically: economizer 1, economizer 2, economizer 3, and economizer 4 are arranged in sequence along the flow direction of the flue gas.

[0071] The rest of the settings of the waste heat boiler system are consistent with those in Example 1.

[0072] Through the system configuration of Example 1 and Example 2, the waste heat boiler arrangement structure for burning high calorific value garbage can be realized. The effects of the above embodiments and the prior art are compared as shown in Table 5 below.

[0073] Table 5 Comparison of the effects of Example 1, Example 2 and the prior art

[0074]

[0075] Compared with the existing conventional waste heat boiler layout structure, the present invention has the following advantages:

[0076] 1) The whole system consists of three flues, which saves one or two flues compared with the conventional solution, and is expected to save more than 30% of land and reduce the total weight of the boiler by more than 20%;

[0077] 2) The first flue is equipped with a high-temperature heating surface, and the heat transfer temperature and pressure can reach 500°C, which is more than three times that of the existing conventional solution. It is expected that at least 60% of the high-temperature heating surface can be saved. At the same time, due to the burning of high-calorific value garbage, the theoretical combustion temperature is greater than 1200°C. Even if a certain number of heating surfaces are arranged in the first flue, it can ensure that the flue gas stays in the flue temperature area above 850°C for 2S;

[0078] 3) The average heat exchange temperature and pressure in the second flue convection heat exchange area can reach above 120°C, which is more than twice that of the conventional solution. It is expected to save 50% of the low-temperature heating surface. In order to maintain the exhaust temperature, the heating surface of the economizer is increased accordingly;

[0079] 4) The high-temperature heating surface moves forward, and the low-temperature convective heat exchange area has a sufficiently large temperature and pressure, which solves the problem that the heat absorption required by the convective heat exchange area of ​​high parameters, especially the waste heat boiler with reheating, is greater than the maximum heat release. The layout of the heating surface in the convection area is more flexible;

[0080] 5) Necessary anti-corrosion measures have been taken into account for the high-temperature heating surface, which can ensure that the service life of the high-temperature heating surface tube screen is not less than 6 years. At the same time, the flue gas temperature in the low-temperature heating surface area is strictly controlled, the corrosion of the low-temperature heating surface is controllable, and the system operation is safe and reliable.

[0081] Through the above measures, the waste heat boiler layout structure for burning high calorific value garbage of the present invention has the advantages of small footprint, light boiler weight, high heat transfer temperature and pressure, and sufficient temperature and pressure in the convection area compared with the existing solutions.

[0082] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A waste heat boiler arrangement structure for burning high calorific value garbage, comprising a combustion furnace and a first flue, a second flue and a third flue connected in sequence along the flue gas flow direction, characterized in that: A high-temperature heating surface is arranged in the first flue, a water-cooled evaporation screen and a low-temperature heating surface are arranged in sequence along the flue gas flow direction in the second flue, and an economizer is arranged in the third flue; The high-temperature heating surface is arranged in the middle of the first flue and is arranged in a downstream manner; the water-cooled evaporation screen adopts a screen structure and includes upper and lower headers and a water-cooled tube bundle, and the water-cooled evaporation screen and the low-temperature heating surface are arranged in a countercurrent manner; The high-temperature heating surface adopts a serpentine tube structure and the header of the high-temperature heating surface is arranged outside the first flue and close to the front side of the incineration furnace. The tube wall surface of the high-temperature heating surface is provided with anti-corrosion material; The high-temperature stage heating surface includes at least a high-temperature stage superheater and a high-temperature stage reheater; the low-temperature stage heating surface includes at least a low-temperature stage superheater and a low-temperature stage reheater; The low-temperature heating surface that cannot be arranged in the second flue is arranged upstream of the economizer in the third flue, and the second flue or the third flue is also arranged with an evaporator arranged upstream or downstream of the low-temperature heating surface; The waste heat boiler arrangement structure also includes an air preheating unit and a feed water heating unit. The feed water heating unit uses saturated steam from the drum to heat part of the feed water sent to the economizer. The air preheating unit extracts steam from the drum and the steam turbine and preheats the primary air and the secondary air. The outlet flue gas temperature of the first flue is controlled at 800°C to 850°C, the outlet flue gas temperature of the water-cooled evaporation screen is controlled at 500°C to 650°C, the outlet flue gas temperature of the second flue is controlled at 300°C to 400°C, and the outlet flue gas temperature of the third flue is controlled at 180°C to 220°C; When the high-temperature heating surface and the low-temperature heating surface do not include the high-temperature reheater and the low-temperature reheater, the steam-water flow of the waste heat boiler arrangement structure is as follows: the feed water is first introduced into the economizer, and then introduced into the boiler drum through the connecting pipe, the boiler water of the boiler drum is respectively sent to the first flue, the second flue, the third flue and the water-cooled evaporation screen to exchange heat with the flue gas, the saturated steam of the boiler drum is introduced into the low-temperature superheater through the connecting pipe, and then flows through the high-temperature superheater, and is led out from the outlet of the high-temperature superheater to the high-pressure cylinder of the steam turbine to perform work; When the high-temperature stage heating surface and the low-temperature stage heating surface include a high-temperature stage reheater and a low-temperature stage reheater, the steam-water flow on the reheat steam side in the waste heat boiler arrangement structure is as follows: the reheated steam is introduced from the turbine side and sent to the low-temperature stage reheater, flows through the high-temperature stage reheater, is led out from the high-temperature stage reheater outlet, and is then sent to the low-pressure cylinder of the turbine to perform work.

2. The waste heat boiler arrangement structure for burning high calorific value garbage according to claim 1 is characterized in that: The first flue is a water-cooled flue, the second flue is a water-cooled flue, and the third flue is a water-cooled flue, a steam-cooled flue, or a combination of water-cooled and steam-cooled flue.

3. The waste heat boiler arrangement structure for burning high calorific value garbage according to claim 1 is characterized in that: The flue gas flow of the waste heat boiler arrangement structure is as follows: the high-temperature flue gas generated by the burning of garbage in the incineration furnace flows through the first flue, the second flue and the third flue in sequence and is led out through the economizer outlet into the flue gas purification system.

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