Waste heat boiler system for improving steam parameters at outlet of superheater of garbage incinerator

Abstract

The utility model discloses a waste heat boiler system for improving steam parameters of a superheater outlet of a garbage incinerator, which comprises a first flue, a second flue and a third flue which are sequentially connected in series on the smoke side, the first flue is communicated with the incinerator, and an evaporator and a coal economizer are sequentially arranged in a horizontal flue at the tail of the third flue; water cooling walls are laid on the second flue and the third flue, the superheater is arranged on the first flue in a membrane wall mode, an inlet of the superheater is connected with a steam outlet of the steam pocket through a steam pipeline, and an outlet of the superheater is connected to the steam turbine through a steam pipeline. A refractory material is laid on the superheater, the superheater absorbs heat in the first flue so that steam can be heated and pressurized and conveyed to the steam turbine, and the steam turbine drives the generator to rotate to generate electricity. According to the utility model, the superheater of the waste heat boiler is placed in the front high-temperature hearth and is protected by the refractory material, so that the steam parameter pressure at the outlet of the superheater can be improved, and the temperature can reach more than 500 DEG C, thereby improving the heat efficiency of the whole plant.

Description

Technical Field

[0001] The utility model relates to the technical field of garbage incineration treatment, in particular to a waste heat boiler system for improving steam parameters at a superheater outlet of a garbage incinerator. Background Art

[0002] Domestic waste incineration treatment technology has been widely used in various cities. Waste incineration produces high-temperature flue gas, which is used in waste heat boilers to absorb heat and produce high-temperature and high-pressure steam for power generation.

[0003] The waste heat boiler absorbs heat to produce steam with certain parameters. The steam parameters of the waste heat boilers currently in operation range from medium temperature and medium pressure to medium temperature and ultra-high pressure. Since the flue gas produced by the waste incinerator contains a large amount of corrosive gases such as hydrogen chloride and sulfur dioxide, according to Figure 1 The relationship between the tube wall temperature and the corrosion rate shown in the figure shows that the corrosive gas in the flue gas will corrode the metal tube wall in the furnace within a certain temperature range, and the high-temperature corrosion of the tube wall begins to accelerate after the wall temperature reaches 450°C. The water-cooled wall of the boiler is not in the corrosion acceleration zone because the medium temperature in the tube is lower than 350°C, so it is less affected by high-temperature corrosion. Due to the existence of high-temperature corrosion problems, it is difficult to improve the parameters of steam generated by waste incineration, which ultimately affects the improvement of the thermal efficiency of the entire power plant. Increasing the parameters will cause accelerated corrosion of the superheater, affecting the safe operation of the boiler; using metal material tubes with higher temperature tolerance and stronger corrosion resistance will only extend the service life and cannot cure the corrosion problem.

[0004] Specifically, first of all, since the high-temperature flue gas generated by the incineration of domestic waste contains a large amount of corrosive gases, the steam temperature at the superheater outlet is generally designed to be between 400℃ and 450℃ (depending on the design parameters of the waste heat boiler). According to the Rankine cycle principle, increasing the steam parameters can improve the cycle thermal efficiency. If the steam temperature at the superheater outlet is increased to above 500℃, the corrosion caused by ferric chloride or alkali iron sulfate will accelerate sharply; and the waste incineration flue gas contains a large amount of corrosive gases such as hydrogen chloride and sulfur dioxide, which will cause accelerated corrosion of the superheater tube wall and affect the safe operation of the boiler.

[0005] Secondly, when the wall thickness is reduced to a certain extent (about 30% wall thickness), the whole furnace is shut down for replacement, and the service life is about 2 to 3 years. When the furnace is shut down for replacement, it will incur a large maintenance cost and a long maintenance time, which will affect the treatment of domestic waste. In cities with greater pressure on domestic waste treatment, this method will affect the safety and stability of waste treatment. In addition, the degree of thinning of the pipe wall is inconsistent. If the thinning deviation is serious in some positions, it is easy to cause a pipe explosion accident, affecting the safe operation of the waste heat boiler.

[0006] Thirdly, replacing the superheater material with a metal tube that can withstand higher temperatures and has better corrosion resistance can extend the service life of the superheater by about 2 to 3 years. However, this solution requires additional investment costs during initial construction. The cost of heat-resistant and corrosion-resistant stainless steel is 4 to 5 times that of ordinary superheater materials, and it cannot completely cure the corrosion problem, which will still affect garbage disposal and safe operation of the boiler. Utility Model Content

[0007] The technical problem to be solved by the utility model is: in view of the above problems in the prior art, a waste heat boiler system is provided which has a compact structure, high thermal energy utilization rate and excellent corrosion resistance and is capable of improving the steam parameters at the outlet of the superheater of a garbage incinerator.

[0008] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0009] A waste heat boiler system for improving the steam parameters at the outlet of a superheater of a garbage incinerator comprises: a first flue, a second flue, a third flue, a superheater, a steam drum, an evaporator and an economizer; the first flue, the second flue and the third flue on the flue gas side are connected in series in sequence, the first flue is connected to the incinerator, and the evaporator and the economizer are arranged in sequence in a horizontal flue at the tail end of the third flue; the second flue and the third flue are both provided with water-cooled walls, the superheater is arranged in the first flue, the inlet of the superheater is connected to the steam outlet of the steam drum through a steam pipe, and the outlet of the superheater is connected to a steam turbine through a steam pipe; refractory material is provided on the superheater, the superheater absorbs heat in the first flue to increase the temperature and pressure of the steam and transport it to the steam turbine, and the steam turbine drives the generator to rotate and generate electricity.

[0010] As a further improvement of the present invention, the superheater is laid on the side wall of the first flue in the form of a membrane wall.

[0011] As a further improvement of the utility model, a fire-facing surface of the membrane wall is coated with refractory material to cover the surface of the membrane wall, so as to isolate the membrane wall from smoke.

[0012] Compared with the prior art, the advantages of the utility model are:

[0013] The utility model discloses a waste heat boiler system for improving the steam parameters at the outlet of the superheater of a waste incinerator, places the superheater in the front high-temperature furnace and adopts refractory material for protection, thereby preventing the superheater from being corroded by flue gas and thinning and bursting, and reducing the maintenance cost; further, since the superheater does not contact the corrosive high-temperature flue gas, the superheater can be manufactured with ordinary grade heat-resistant metal materials, saving the manufacturing material cost; under the premise of avoiding the corrosion of the superheater, the steam parameters of the waste incineration waste heat boiler are improved, so that the final superheated steam parameters are increased, the generated steam parameter pressure is increased, the temperature reaches above 500°C, and the overall thermal efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the relationship between the superheater tube wall temperature and the corrosion rate;

[0015] Figure 2 It is a schematic diagram of the structural principle of a waste heat boiler system for improving steam parameters at the outlet of a superheater of a garbage incinerator in a specific embodiment of the utility model;

[0016] Figure 3 This is a schematic diagram of the flow of the steam-water cycle in a specific embodiment of the utility model;

[0017] Legend: 1. Incinerator; 2. First flue; 3. Second flue; 4. Third flue; 5. Superheater; 6. Water-cooled wall; 7. Steam drum; 8. Evaporator; 9. Economizer. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0019] In the description of the present invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0021] Example

[0022] like Figure 2 and Figure 3 As shown, the waste heat boiler system for improving the steam parameters at the outlet of the superheater of the garbage incinerator of the utility model comprises: a first flue 2, a second flue 3, a third flue 4, a superheater 5, a drum 7, an evaporator 8 and an economizer 9. The first flue 2, the second flue 3 and the third flue 4 on the flue gas side are connected in series in sequence, the first flue 2 is connected to the incinerator 1, the evaporator 8 and the economizer 9 are arranged in sequence in the horizontal flue at the tail of the third flue 4, and the flue gas generated by the burning of garbage in the incinerator 1 flows through the first flue 2, the second flue 3, the third flue 4 and the horizontal flue at the tail of the third flue 4 in sequence, and is finally discharged to the flue gas reaction tower for purification. The second flue 3 and the third flue 4 are both provided with water-cooled walls 6, the superheater 5 is arranged in the first flue 2, the inlet of the superheater 5 is connected to the steam outlet of the drum 7 through a steam pipe, and the outlet of the superheater 5 is connected to the steam turbine through a steam pipe. The superheater 5 is coated with refractory materials, and the superheater 5 absorbs the heat in the first flue 2 to increase the temperature and pressure of the steam and transmit it to the steam turbine, which drives the generator to rotate and generate electricity.

[0023] In this embodiment, the superheater 5 is placed in the front high-temperature furnace and protected by refractory materials, which prevents the superheater 5 from being corroded by flue gas and thinned and burst in the waste incineration waste heat boiler, thereby reducing the maintenance cost. Furthermore, since the superheater 5 does not contact the corrosive high-temperature flue gas, the superheater 5 can be manufactured using ordinary grade heat-resistant metal materials, saving the cost of manufacturing materials. Under the premise of avoiding superheater corrosion, the steam parameters of the waste incineration waste heat boiler are improved, so that the final superheated steam parameter pressure is increased and the temperature reaches above 500°C, thereby improving the overall power generation efficiency.

[0024] like Figure 2As shown, in this embodiment, the part of the furnace of the first flue 2 that was originally provided with water-cooled walls is changed to a membrane-walled superheater 5, and the furnace structure is kept unchanged, that is, the water-cooled wall is provided in the area near the incinerator at the bottom of the first flue 2, and the membrane-walled superheater 5 is provided in the remaining part of the first flue 2. The inlet header of the membrane wall superheater is connected to the saturated steam connecting pipe, and the outlet header of the membrane wall is connected to the outlet collecting header of the superheater 5. The collecting header is connected to the main steam pipeline to the steam turbine for power generation. Specifically, pins are provided on the fire surface of the membrane wall and refractory materials are laid to cover the surface of the membrane wall so that it does not come into direct contact with the flue gas. It can be understood that the specific laying area of ​​the membrane wall in the first flue 2 can be calculated according to the actual application requirements; the specific type of refractory material can also be selected according to the actual application requirements.

[0025] In this embodiment, since the superheater 5 is protected by refractory materials, the heat transfer effect is weakened. The superheater 5 is set in the high temperature area of ​​the incinerator furnace, and the flue gas temperature reaches 850-1100°C, which can ensure that the superheated steam outlet temperature reaches the preset requirements. The superheater 5 is set in the first flue 2 of the furnace, and the superheater 5 is covered and protected by refractory materials with good heat conductivity. The superheater 5 is then heated by the high temperature and radiation inside the first flue 2, so that the steam in the superheater 5 is heated. Figure 3 As shown in , the saturated steam generated by the drum 7 is directly connected to the inlet of the superheater 5, and superheated steam is generated inside by heating. The parameter pressure of the superheated steam is increased, and the temperature reaches above 500°C. A superheater heating surface is set in the first flue 2, and is coated and protected with refractory materials with good heat transfer coefficient, so that the flue gas heat generated by burning garbage is transferred to the superheater 5 but does not directly contact the superheater 5, protecting the superheater 5 from flue gas corrosion. The superheater set in the original furnace tail flue is changed to a water-cooled evaporator, which meets the requirements of tail exhaust temperature and boiler evaporation volume. The medium temperature inside the evaporator is below 350°C, which is not in the rapid corrosion range, and can meet the requirements of heating surface corrosion protection.

[0026] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A waste heat boiler system for improving steam parameters at the outlet of a waste incinerator superheater, characterized in that: include: A first flue (2), a second flue (3), a third flue (4), a superheater (5), a steam drum (7), an evaporator (8) and an economizer (9); the first flue (2), the second flue (3) and the third flue (4) on the flue gas side are sequentially connected in series, the first flue (2) is communicated with the incinerator (1), the evaporator (8) and the economizer (9) are sequentially arranged in a horizontal flue at the tail end of the third flue (4); the second flue (3) and the third flue (4) are both provided with water-cooled walls (6), the superheater (5) is arranged in the first flue (2), the inlet of the superheater (5) is connected to the steam outlet of the steam drum (7) through a steam pipe, and the outlet of the superheater (5) is connected to the steam turbine through a steam pipe; a refractory material is provided on the superheater (5), the superheater (5) absorbs heat in the first flue (2) to increase the temperature and pressure of the steam and transport it to the steam turbine, and the steam turbine drives the generator to rotate and generate electricity.

2. The waste heat boiler system for improving steam parameters at the outlet of the superheater of a garbage incinerator according to claim 1 is characterized in that: The superheater (5) is laid on the side wall of the first flue (2) in the form of a membrane wall.

3. The waste heat boiler system for improving steam parameters at the outlet of the superheater of a garbage incinerator according to claim 2 is characterized in that: The fire-facing surface of the membrane wall is coated with refractory material to cover the surface of the membrane wall, so as to isolate the membrane wall from smoke.

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