A structure of pre-optimization desuperheating measure based on heat supply steam waste heat boiler evaporator

Abstract

This utility model discloses a structure for optimized pre-evaporator desuperheating measures based on a waste heat boiler for heating steam. The structure includes a boiler flue, within which multiple sets of evaporators and superheaters are arranged. The superheaters are positioned downstream of the flue gas from a certain set of evaporator tube panels. The upper end of each evaporator is connected to the boiler drum via a riser pipe, and the lower end is connected to a downcomer via a water inlet branch pipe. The downcomer is connected to the boiler drum. The upper end of the superheater is connected to the boiler drum via a saturated steam outlet pipe, and the lower end is connected to a steam outlet pipe. This utility model, by adjusting the arrangement of the evaporators pre-positioned, effectively controls the waste heat gradient utilization of the flue gas. Whether in supplementary combustion or non-supplementary combustion conditions, it can more effectively control the steam temperature, while also saving on the configuration of the desuperheating system, optimizing system control, and improving the unit's operating efficiency.

Description

Technical Field

[0001] This utility model relates to the field of gas turbine power generation technology, and in particular to a structure based on the pre-evaporator optimization and de-heating measures of a waste heat boiler for heating steam, which is used to supply slightly superheated steam from a gas turbine waste heat boiler to industrial steam turbine units. Other similar boiler structures can be used as a reference. Background Technology

[0002] Waste heat boilers for industrial heating steam are currently widely used in self-owned power plants in industries such as chemical and papermaking. The significant characteristics of this field are that the electricity consumption is fixed, the power generation and grid connection are limited, the main demand is for steam parameters that are mostly saturated or slightly superheated, the steam quality requirements are relatively low, and the temperature control range is large. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model designs a structure for optimizing the desuperheating measures before the evaporator based on a waste heat boiler for heating steam. By adjusting the arrangement of the evaporator before the evaporator, the waste heat gradient utilization of the flue gas can be effectively controlled. Whether in supplementary combustion or non-supplementary combustion conditions, the steam temperature can be controlled more effectively. At the same time, it can save on the configuration of the desuperheating system, optimize system control, and improve the operating efficiency of the unit.

[0004] The present invention adopts the following technical solution: A structure for pre-evaporator optimization and de-cooling measures based on a waste heat boiler for heating steam includes a boiler flue. Multiple sets of evaporators and superheaters are arranged in the boiler flue. The superheaters are arranged downstream of the flue gas of a certain set of evaporator tube panels. The upper end of the evaporator is connected to the boiler drum through a riser pipe, and the lower end is connected to the downcomer through a water inlet branch pipe. The downcomer is connected to the boiler drum. The upper end of the superheater is connected to the boiler drum through a saturated steam outlet pipe, and the lower end of the superheater is connected to a steam outlet pipe.

[0005] The boiler drum, evaporator I, evaporator II, evaporator III, riser pipe, downcomer pipe, and inlet branch pipe constitute the evaporation circulation system. The saturated steam outlet pipe, superheater, and superheated steam outlet pipe constitute the steam discharge system after slight superheating. By placing the superheater behind the steam generator, the temperature of the flue gas passing through the superheater is reduced, which can effectively control the temperature of the superheated steam and save the need for a desuperheater system in the superheated steam outlet pipe.

[0006] Preferably, the multiple evaporators include evaporator I, evaporator II and evaporator III, with the superheater arranged downstream of the flue gas in the tube panel of evaporator II.

[0007] Preferably, a burner is added to the flue before the evaporator II.

[0008] Preferably, a denitrification device is added to the flue after the evaporator II.

[0009] Preferably, the evaporator II adopts a two-stage evaporator form consisting of a bare tube and a finned tube.

[0010] Preferably, the flue gas temperature at the superheater after the evaporator II is 280~340℃.

[0011] The beneficial effects of this utility model are: (1) In the conventional mode, the superheater of the boiler is arranged in the front row. Because the steam parameters of the industrial heating gas turbine waste heat boiler are relatively low, generally 200~250℃, and the exhaust temperature of the gas turbine at full load is above 500℃, the steam temperature generated by the superheater being arranged in the front is relatively high, requiring a large amount of desuperheating water to control the temperature. This brings great safety hazards to the system and is uneconomical and inefficient. By adopting the arrangement structure of this utility model patent, the evaporator is placed in front, which can effectively utilize the flue gas in a gradient. Moreover, under the condition that the pressure in the evaporator system is constant, the temperature of the saturated steam is constant, thereby ensuring that the outlet temperature of the superheated steam is effectively controlled; (2) The desuperheater system is reduced, the selection of water pump is reduced, the configuration of desuperheating water control valve is eliminated, and the impact on the system temperature under multiple operating conditions of the gas turbine is reduced, improving the safety performance of the equipment and having a significant effect on energy saving and emission reduction of the system. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; In the diagram: 1. Evaporator I, 2. Evaporator II, 3. Superheater, 4. Evaporator III, 5. Boiler drum, 6. Downcomer, 7. Evaporator I riser pipe, 8. Evaporator II riser pipe, 9. Saturated steam outlet pipe, 10. Evaporator III riser pipe, 11. Evaporator I inlet branch pipe, 12. Evaporator II inlet branch pipe, 13. Superheated steam outlet pipe, 14. Evaporator III inlet branch pipe. Detailed Implementation

[0013] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings: Example: Figure 1As shown, a structure for pre-evaporator optimization and desuperheating measures based on a waste heat boiler for heating steam includes a boiler flue. Evaporators I1, II2, and III4 are arranged within the boiler flue. A superheater 3 is arranged downstream of the flue gas flow of evaporator II2. Evaporators I1, II2, and III4 are connected by evaporator I inlet branch pipe 11, evaporator II inlet branch pipe 12, evaporator III inlet branch pipe 14, and evaporator I riser pipe 7, evaporator II riser pipe 8, and evaporator III riser pipe 10, respectively. The superheater 3 is connected to a saturated steam outlet pipe 9 and a superheated steam outlet pipe 13. Evaporator I inlet branch pipe 11, evaporator II inlet branch pipe 12, evaporator III inlet branch pipe 14, and saturated steam outlet pipe 9 are connected to the boiler drum 5. Evaporator I riser pipe 7, evaporator II riser pipe 8, and evaporator III riser pipe 10 are connected to a downcomer 6, which is connected to the boiler drum 5. The boiler drum 5, evaporator I1, evaporator II2, evaporator III4, evaporator I riser pipe 7, evaporator II riser pipe 8, evaporator III riser pipe 10, downcomer 6, evaporator I inlet branch pipe 11, evaporator II inlet branch pipe 12, and evaporator III inlet branch pipe 14 form an evaporation circulation system. The saturated steam outlet pipe 9, superheater 3, and superheated steam outlet pipe 13 form a discharge system for the slightly superheated saturated steam.

[0014] In this arrangement, a burner can be added before evaporator II. In this case, evaporator II should preferably be a two-stage evaporator consisting of a bare tube and a finned tube. A denitrification device can be added after evaporator II. The flue gas temperature here is approximately 280~340℃. At this point, attention should be paid to the arrangement of the superheater to ensure that the temperature difference between the superheated steam outlet temperature and the inlet flue gas temperature of the superheated tube screen is at least 30~40℃.

[0015] The front row arrangement places evaporator I1 directly facing the flue gas with the highest temperature. According to the basic heat transfer equation Q = U × A × ΔT, an increase in the inlet flue gas temperature will directly lead to a significant increase in the heat absorbed Q of evaporator I1. Therefore, attention needs to be paid to FAC corrosion in evaporator I1. For low-pressure systems, it is generally recommended to use a more wear-resistant alloy steel material, 12Cr1MoVG. Similarly, if a burner is arranged between evaporator I1 and evaporator II2, attention should also be paid to the FAC corrosion of the first few rows of bare tubes in evaporator II2, and it is also recommended to use 12Cr1MoVG material for this purpose.

[0016] In this scheme, the waste heat boiler's evaporators I1, II2, and III4 employ a natural circulation method. Its core principle relies on the density difference between the saturated water in the downcomer 6 and the steam-water mixture in the riser bundles of evaporators I1, II2, and III4 to drive water circulation.

[0017] The gas-water circulation scheme of this arrangement meets the requirements and ensures a circulation ratio of approximately 15-20 without supplemental combustion, and approximately 8 under supplemental combustion conditions.

[0018] Within the evaporation cycle system, because the saturated pressure of the medium remains constant, the temperature fluctuation of the saturated steam exiting the boiler drum 5 is very small. Under basic load, the temperature fluctuation of the superheated steam is also within the control range. By placing the superheater 3 behind the steam generator 2, the temperature of the flue gas passing through the superheater 3 can be reduced, which can effectively control the temperature of the superheated steam, save the desuperheating water system of the superheated steam outlet pipe, reduce the energy consumption of the system, and improve the efficiency of the unit.

[0019] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A structure of evaporator preposition optimization desuperheating measure based on heat supply steam waste heat boiler, comprising a boiler flue, characterized in that, The boiler flue is equipped with multiple sets of evaporators and superheaters. The superheaters are located downstream of the flue gas of a certain set of evaporator tube panels. The upper end of the evaporator is connected to the boiler drum through a riser pipe, and the lower end is connected to the downcomer pipe through a water inlet branch pipe. The downcomer pipe is connected to the boiler drum. The upper end of the superheater is connected to the boiler drum through a saturated steam outlet pipe, and the lower end of the superheater is connected to the steam outlet pipe.

2. A structure of a pre-evaporator optimization desuperheating measure based on a heat supply steam waste heat boiler according to claim 1, characterized in that, The multiple evaporators include evaporator I, evaporator II and evaporator III, with the superheater arranged downstream of the flue gas in the tube panel of evaporator II.

3. A structure of pre-evaporator optimization desuperheating measure based on heat supply steam waste heat boiler according to claim 2, characterized in that, A burner is added to the flue before the evaporator II.

4. The structure of the evaporator pre-optimization desuperheating measure based on the heat supply steam waste heat boiler according to claim 2, characterized in that, A denitrification device is added to the flue after the evaporator II.

5. The structure of an evaporator pre-cooling optimization measure based on a waste heat boiler for heating steam, as described in claim 2, is characterized in that... Evaporator II adopts a two-stage evaporator form consisting of a bare tube and a finned tube.

6. A structure of a pre-evaporator optimization desuperheating measure based on a heat supply steam waste heat boiler according to claim 2, characterized in that, The flue gas temperature at the superheater after evaporator II is 280~340℃.

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