Semi-dry flue gas denitration system of gas turbine unit

Abstract

The utility model discloses a gas turbine unit semi-dry flue gas denitration system which comprises an oxidation layer and an adsorption layer, the oxidation layer is located above the adsorption layer, the upper portion of the oxidation layer is communicated with a flue gas inlet channel, the lower portion of the adsorption layer is communicated with a flue gas outlet channel, and a raw flue gas analyzer is arranged in the flue gas inlet channel above the oxidation layer. A clean flue gas analyzer is arranged in the flue gas outlet channel, a liquid collecting pool is further arranged under the adsorption layer, the adsorption layer comprises an atomization dosing layer and a plate type reactor and is used for adsorbing and removing nitric oxide in flue gas, and the plate type reactor comprises an adsorption plate fixing pin, an adsorption layer frame and an adsorption plate. The adsorption plates in the plate-type reactor are distributed in a Z shape. According to the technical scheme of the utility model, the efficient removal of nitrogen oxides in the flue gas discharged from the tail part of the gas turbine unit is realized; efficient utilization of the absorption liquid is realized, and the operation cost is reduced; by adopting an atomization spraying semi-dry method and Z-shaped distribution of the adsorption plates, the system resistance is small, the reaction retention time is long, and the denitration efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flue gas denitration, and in particular relates to a semi-dry flue gas denitration system for a gas turbine unit. Background Art

[0002] Natural gas power generation is an important form of power generation in my country. Compared with traditional coal-fired power generation, it has the advantages of high energy efficiency, low pollution, and strong flexibility. However, domestic gas-fired units are frequently started and stopped as peak-shaving units, and high concentrations of nitrogen oxides are emitted during the start-up and shutdown stages and under special operating conditions. With the increase in the number of gas-fired units and the extension of their operating time, the problem of nitrogen oxide emissions has become increasingly prominent.

[0003] At present, the commonly used denitrification technologies for gas units mainly include low-nitrogen combustion technology, selective catalytic reduction technology (SCR) dry denitrification and wet denitrification technology. The investment cost of SCR technology is relatively high, the catalyst reaction temperature window is relatively high, and the waste heat boiler space of some in-service units is insufficient, and the energy consumption of heating the flue after the furnace is relatively large; low-nitrogen combustion technology has problems such as unstable combustion and poor load adaptability due to the limitations of low-nitrogen burners; wet denitrification technology requires a large amount of absorption liquid, which increases the investment cost.

[0004] In order to respond to the national development concept that green mountains and clear waters are invaluable assets, it is necessary to explore new technologies to improve the nitrogen oxide emission standards of power units. Utility Model Content

[0005] In view of the above-mentioned problems, the utility model provides a semi-dry flue gas denitrification system for a gas turbine unit, which can, on the one hand, remove nitrogen oxides in the flue gas discharged at the tail of the gas unit; on the other hand, it can achieve efficient utilization of the absorption liquid, increase the reaction residence time, and reduce the operating cost, thereby solving the above-mentioned problems existing in the existing flue gas denitrification technology.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A semi-dry flue gas denitrification system for a gas turbine unit comprises an oxidation layer and an adsorption layer, wherein the oxidation layer is located above the adsorption layer, the oxidation layer is connected to a smoke inlet channel above the oxidation layer, and the adsorption layer is connected to a smoke outlet channel below the oxidation layer, a raw flue gas analyzer is arranged in the smoke inlet channel above the oxidation layer, a clean flue gas analyzer is arranged in the smoke outlet channel, and a liquid collecting tank is arranged directly below the adsorption layer, the adsorption layer comprises an atomizing dosing layer and a plate reactor for adsorbing and removing nitrogen oxides in the flue gas, the plate reactor comprises an adsorption plate fixing pin, an adsorption layer frame and an adsorption plate, and each adsorption plate in the plate reactor is distributed in a Z shape.

[0008] Furthermore, the adsorption plate includes an upper pressure plate frame, an adsorption material, and a lower pressure plate frame, which are stacked in sequence. The adsorption material can be fiber cotton; the upper and lower pressure plate frames can be made of stainless steel 304; the adsorption plate is clamped and fixed by an adsorption plate fixing pin.

[0009] Furthermore, the angle between adjacent adsorption plates is set at 25-30°.

[0010] Furthermore, the atomizing and dosing layer is located on the upper part of the adsorption layer, and is provided with a plurality of atomizing nozzles connected by pipelines. The atomizing nozzles are gas-liquid two-phase flow atomizing nozzles, and compressed air atomizes the absorption liquid.

[0011] Furthermore, the liquid collecting pool is located at the bottom of the smoke outlet channel just below the adsorption layer, and the liquid collecting pool is provided with a flushing pipe and a liquid outlet pipe, the flushing pipe is provided with an electric flushing valve, and the liquid outlet pipe is provided with an electric drain valve and a pump.

[0012] Furthermore, the pump outlet pipeline is divided into a first branch pipeline and a second branch pipeline, the first branch pipeline is provided with a wastewater valve and is connected to the wastewater pool, and the second branch pipeline is provided with a dosing valve and is connected to the atomization dosing layer of the adsorption layer.

[0013] Furthermore, the second branch pipeline is also connected to a solution / flushing water pipeline, and a solution / flushing water valve is provided on the solution / flushing water pipeline.

[0014] Furthermore, the pump is a centrifugal pump for conveying absorption liquid, flushing water and waste water.

[0015] Furthermore, the flushing pipe is connected to the second branch pipeline.

[0016] Furthermore, the absorption liquid may be an alkaline solution. Preferably, the absorption liquid may be NaOH or sodium carbonate solution.

[0017] The raw flue gas analyzer monitors the raw flue gas parameters of the unit in real time, such as O2, NOx, SO2, temperature, humidity, flow rate, etc.

[0018] The clean flue gas analyzer monitors the unit's exhaust gas parameters in real time, such as O2, NOx, SO2, temperature, humidity, etc.

[0019] Preferably, the oxidizing substance used in the oxidation layer may be ozone.

[0020] Preferably, a guide plate can be added at the oxidation layer to improve the flue gas oxidation efficiency, ensure the uniform distribution of flue gas in the downstream adsorption layer, and improve the removal efficiency.

[0021] The absorption liquid in the adsorption layer reacts with NOx in the flue gas to generate nitrate and nitrite, and the reaction is as follows:

[0022] NO+NO2+2NaOH→2NaNO2+H2O

[0023] 2NO2+2NaOH→NaNO3+NaNO2+H2O

[0024] When the adsorption layer is cleaned, industrial water or desalted water is used to spray the adsorption layer from top to bottom to dissolve and wash the nitrate, nitrite and sodium carbonate in the absorption layer.

[0025] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0026] (1) Through the technical solution of the utility model, efficient removal of nitrogen oxides in the flue gas discharged from the tail of the gas unit is achieved;

[0027] (2) The utility model realizes efficient utilization of the absorption liquid by setting up the recycling of the absorption liquid, thereby increasing the reaction residence time and reducing the operating cost;

[0028] (3) The utility model adopts a semi-dry method of atomized spraying + Z-shaped distribution of adsorption plates, which has a small system resistance, a long reaction residence time, and improves the denitrification efficiency. Atomized spraying improves the utilization rate of the absorption liquid, and the absorption liquid adheres to the adsorption layer, reducing the loss of the absorption liquid; the Z-shaped distribution increases the flue gas flow area per unit flue volume, reduces the reactor resistance, and increases the reaction residence time of the flue gas in the adsorption layer, thereby improving the denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of the semi-dry flue gas denitrification system of the utility model;

[0030] Figure 2 This is a schematic diagram of the adsorption layer structure of the utility model;

[0031] Figure 3 This is a schematic diagram of the atomization dosing layer structure of the utility model;

[0032] In the figure: 1. Oxidation layer; 2. Adsorption layer; 21. Atomization and dosing layer; 22. Adsorption plate fixing pin; 23. Adsorption layer frame; 24. Adsorption plate; 3. Liquid collecting tank; 4. Pump; 51. Solution / flushing water valve; 52. Electric drain valve; 53. Electric flushing valve; 54. Dosing valve; 55. Wastewater valve; 6. Raw flue gas analyzer; 7. Clean flue gas analyzer; 8. Smoke inlet channel; 9. Smoke outlet channel; A. Flushing pipe; B. Liquid outlet pipe; C. First branch pipeline; D. Second branch pipeline; E. Solution / flushing water pipeline. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the utility model.

[0034] Example 1

[0035] In this embodiment, the flue gas denitrification device of the gas generator set includes an oxidation layer 1, an adsorption layer 2, a liquid collecting tank 3, a pump 4, a solution / flushing water valve 51, an electric drain valve 52, an electric flushing valve 53, a dosing valve 54, a waste water valve 55, a raw flue gas analyzer 6 and a clean flue gas analyzer 7. Figure 1 The oxidation layer 1 is located above the adsorption layer 2, the oxidation layer 1 is connected to the smoke inlet channel 8 above, and the adsorption layer 2 is connected to the smoke outlet channel 9 below. An original smoke analyzer 6 is arranged in the smoke inlet channel 8 above the oxidation layer 1, and a clean smoke analyzer 7 is arranged in the smoke outlet channel 9. A liquid collecting pool 3 is also arranged directly below the adsorption layer 2.

[0036] The flue gas is drawn from the waste heat boiler of the gas turbine unit, and flows through the original flue gas analyzer 6, the oxidation layer 1, the adsorption layer 2, the clean flue gas analyzer 7 in sequence, and finally returns to the main flue of the unit and is discharged from the chimney.

[0037] The oxidation layer 1 is located in front of the adsorption layer 2 and behind the original flue gas analyzer 6. Ozone is produced by the ozone generator and enters the smoke inlet channel 8 through the nozzle to supplement the oxidized NO and improve the denitrification efficiency. When NO: NO2≥3:1 (volume), the oxidation production device is turned on and sprayed into the flue.

[0038] The adsorption layer 2 is composed of an atomization dosing layer 21 and a plate reactor. Figure 2 .

[0039] The plate reactor is composed of an adsorption plate fixing pin 22, an adsorption layer frame 23, and an adsorption plate 24. The adsorption plates 24 in the plate reactor are distributed in a Z shape with an angle of 30°.

[0040] The adsorption plate 24 is composed of an upper pressing plate frame, fiber cotton, and a lower pressing plate frame stacked in sequence, and is clamped and fixed by the adsorption plate fixing pin 22. The upper and lower pressing plate frames are made of 304 stainless steel.

[0041] The atomized drug-adding layer 21 is as follows Figure 3 As shown, it is located on the upper part of the adsorption layer 2 and contains an atomizing nozzle 211. The atomizing nozzle 211 is a gas-liquid two-phase flow atomizing nozzle, and compressed air atomizes the absorption liquid NaOH solution. There are 12 nozzles in total, which are connected to the main pipe through pipelines.

[0042] The liquid collecting pool 3 is located at the bottom of the flue, and can recover the absorption liquid leaked from the adsorption layer 2 during operation, as well as the waste liquid after the device is shut down for cleaning.

[0043] The liquid collecting tank 3 is provided with a flushing pipe A and a liquid outlet pipe B. The flushing pipe A is provided with an electric flushing valve 53 and an electric valve, and industrial water can be pumped in to flush the liquid collecting tank 3. The liquid outlet pipe B is provided with an electric drain valve 52 and an electric valve, and flushing water or absorption liquid can be discharged by gravity, and then transported to the factory wastewater tank or pumped back to the adsorption layer 2 by the pump 4.

[0044] The outlet pipeline of the pump 4 is divided into a first branch pipeline C and a second branch pipeline D. The first branch pipeline C is provided with a wastewater valve 55 and is connected to the wastewater pool. The second branch pipeline D is provided with a dosing valve 54 and is connected to the atomized dosing layer 21 of the adsorption layer 2. The second branch pipeline D is also connected to a solution / flushing water pipeline E, and a solution / flushing water valve 51 is provided on the solution / flushing water pipeline E. The solution / flushing water valve 51 can control the delivery of the absorption liquid or the flushing water.

[0045] Furthermore, the flushing pipe A is connected to the second branch pipe D.

[0046] The centrifugal pump 4 is used to transport absorption liquid, flushing water and waste water.

[0047] The raw flue gas analyzer 6 monitors raw flue gas parameters, including O2, NOx, temperature and flow rate, in real time.

[0048] The clean flue gas analyzer 7 monitors the exhaust gas parameters, O2, NOx, and temperature in real time.

[0049] The denitrification process of the utility model system is as follows:

[0050] Step 1: Monitor the original flue gas component parameters to determine whether denitrification is required. If necessary, proceed to step 2;

[0051] Step 2: Open the solution / rinsing water valve 51, the dosing valve 54, and the drain valve 52, close the flushing valve 53 and the waste water valve 55, deliver the alkaline absorption liquid from the solution / rinsing water valve 51, and start the atomization dosing;

[0052] Step 3: Start the oxidation device according to the original flue gas nitrogen oxide concentration;

[0053] Step 4: Monitor the clean flue gas parameters, start and stop the solution / flushing water valve 51 according to the nitrogen oxide concentration of the clean flue gas; start and stop the pump 4 or adjust the flow of the pump 4 according to the liquid level of the liquid collecting tank 3.

[0054] Example 2

[0055] The device of Example 1 was used to open the bypass flue damper and monitor the original flue gas parameters. The flue gas volume was 10m 3 / h, smoke temperature 108℃; open solution / washing water valve 51, dosing valve 54, electric drain valve 52, close electric flushing valve 53, waste water valve 55, start atomization dosing; monitor clean flue gas parameters, and adjust the absorption liquid flow to the atomization dosing layer 21 to ensure that the clean flue gas NOx is lower than 35mg / m 3 The changes of the original flue gas and clean flue gas parameters over time during the denitrification operation are shown in Table 1. It can be seen that the nitrogen oxide content in the flue gas after purification is significantly reduced.

[0056] Table 1 Parameters of raw flue gas and net flue gas during denitrification operation

[0057]

[0058] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A semi-dry flue gas denitrification system for a gas turbine unit, characterized in that: The invention comprises an oxidation layer (1) and an adsorption layer (2), wherein the oxidation layer (1) is located above the adsorption layer (2), the oxidation layer (1) is connected to a smoke inlet channel (8) above the oxidation layer (1), and the adsorption layer (2) is connected to a smoke outlet channel (9) below the oxidation layer (1). An original smoke analyzer (6) is arranged in the smoke inlet channel (8) above the oxidation layer (1), and a clean smoke analyzer (7) is arranged in the smoke outlet channel (9). A liquid collecting pool (3) is also arranged directly below the adsorption layer (2). The adsorption layer (2) comprises an atomizing and dosing layer (21) and a plate reactor for adsorbing and removing nitrogen oxides in the smoke. The plate reactor comprises an adsorption plate fixing pin (22), an adsorption layer frame (23) and an adsorption plate (24), and each adsorption plate (24) in the plate reactor is distributed in a Z shape.

2. A semi-dry flue gas denitration system for a gas turbine unit according to claim 1, characterized in that: The adsorption plate (24) comprises an upper pressure plate frame, an adsorption material, and a lower pressure plate frame, which are stacked in sequence. The adsorption plate (24) is clamped and fixed by an adsorption plate fixing pin (22).

3. A semi-dry flue gas denitration system for a gas turbine unit according to claim 2, characterized in that: The angle between the adjacent adsorption plates (24) is set at 25-30°.

4. A semi-dry flue gas denitration system for a gas turbine unit according to claim 1, characterized in that: The atomizing and dosing layer (21) is located on the upper part of the adsorption layer (2) and is provided with a plurality of atomizing nozzles (211) connected by pipelines. The atomizing nozzles (211) are gas-liquid two-phase flow atomizing nozzles, and compressed air atomizes the absorption liquid.

5. A semi-dry flue gas denitration system for a gas turbine unit according to claim 1, characterized in that: The liquid collecting pool (3) is located at the bottom of the smoke outlet channel (9) directly below the adsorption layer (2). The liquid collecting pool (3) is provided with a flushing pipe (A) and a liquid outlet pipe (B). The flushing pipe (A) is provided with an electric flushing valve (53), and the liquid outlet pipe (B) is provided with an electric drain valve (52) and a pump (4).

6. A semi-dry flue gas denitration system for a gas turbine unit according to claim 5, characterized in that: The outlet pipeline of the pump (4) is divided into a first branch pipeline (C) and a second branch pipeline (D); the first branch pipeline (C) is provided with a wastewater valve (55) and is connected to the wastewater pool; the second branch pipeline (D) is provided with a dosing valve (54) and is connected to the atomized dosing layer (21) of the adsorption layer (2).

7. A semi-dry flue gas denitration system for a gas turbine unit according to claim 6, characterized in that: The second branch pipeline (D) is also connected to a solution / flushing water pipeline (E), and a solution / flushing water valve (51) is provided on the solution / flushing water pipeline (E).

8. A semi-dry flue gas denitration system for a gas turbine unit according to claim 5, characterized in that: The pump (4) is a centrifugal pump used for conveying absorption liquid, flushing water and waste water.

9. A semi-dry flue gas denitration system for a gas turbine unit according to claim 6, characterized in that: The flushing pipe (A) is connected to the second branch pipe (D).

10. A semi-dry flue gas denitration system for a gas turbine unit according to claim 1, characterized in that: The oxidation layer (1) is additionally provided with a guide plate, which is used to improve the flue gas oxidation efficiency and reduce the overall resistance of the system.

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