Flue atomization direct ammonia injection system in activated carbon desulfurization and denitrification process

Abstract

The utility model belongs to the technical field of flue gas denitrification, and discloses a flue atomization direct ammonia injection system in an activated carbon desulfurization and denitrification process. According to the system, an ammonia water mother pipeline is connected with a main ammonia water pump through a first ammonia water branch pipeline and then is divided into two paths through a second ammonia water branch pipeline, one path serves as an ammonia water source of an existing active coke desulfurization and denitrification process, and the other path and a nitrogen pipeline are connected with two inlets of a distribution cabinet respectively; the distribution cabinet distributes a single path of nitrogen and ammonia water into sixteen paths, each path of nitrogen and ammonia water is connected with the two-fluid atomizing spray guns through the spraying pipeline group, and the sixteen two-fluid atomizing spray guns are divided into four groups and are arranged on the periphery of a flue gas outlet of the first-stage adsorption tower. Therefore, the system adopts a mode of directly spraying ammonia through flue atomization, the mixing degree of atomized ammonia water and flue gas is improved through high speed difference, and an extra heat source is not needed. And meanwhile, equipment such as a shut-off valve, a flow meter and a pressure gauge is additionally arranged, so that the safety and the stability of the system are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flue gas denitration, and in particular relates to a flue atomization direct injection ammonia system in an activated carbon desulfurization and denitration process. Background Art

[0002] At present, the ammonia water used in the domestic activated coke desulfurization and denitrification process is evaporated by steam or electric heater. The activated carbon desulfurization and denitrification uses ammonia water with a concentration of 20% for denitrification. The ammonia spraying process is to pressurize the ammonia water through the ammonia water delivery pump and enter the ammonia water evaporator. The concentrated ammonia water is vaporized into ammonia steam by steam. The ammonia steam is mixed with 120℃ dilution air and sprayed into the flue. The diluted ammonia steam is mixed with the flue gas through the ammonia spray grid and enters the adsorption tower with the flue gas for denitrification reaction. However, there are the following problems in the actual production process: (1) During the startup period, unstable steam pressure can easily lead to excessive nitrogen oxides. In order to ensure that the environmental protection data meets the standard, the sintering cannot be fully loaded before the steam pressure is stable at >0.3Mpa. (2) There is no backup for the dilution fan. Once it fails, ammonia cannot be sprayed for denitrification, which eventually leads to excessive nitrogen oxides at the outlet and forced sintering to stop. (3) The heat exchange tube bundle inside the ammonia evaporator is easy to be perforated. Since the evaporator pressure vessel is a special equipment, it is difficult to repair and cannot be repaired by welding, and the maintenance cost is high. Once the equipment leaks, it will cause serious steam leakage on site and affect the denitrification effect. (4) During the autumn and winter defense and startup period, the steam network supply is delayed, and the steam pressure is less than 0.2MPa, which causes the ammonia water to not be completely evaporated. Ammonia steam condenses and accumulates in the ammonia pipeline, and the nitrogen oxide emission is difficult to reach 35mg / m3, which seriously restricts sintering production. (5) The temperature of the ammonia-air mixture after the dilution fan is lower than 100℃. The flue gas entering the end of the grille will form local condensation and cause grille corrosion.

[0003] In addition, sintering is one of the important production process links of steel joint production enterprises. It not only consumes a lot of energy but also produces a lot of dust and harmful gases. Among them, the activated carbon desulfurization and denitrification flue gas purification process can remove multiple pollutants such as SO2, NOx, dioxins and dust at the same time, and can recycle sulfur resources. It is a resource recovery type flue gas comprehensive treatment technology. Therefore, it is particularly important to propose a transformation of the existing activated coke desulfurization and denitrification process. Utility Model Content

[0004] Aiming at the many problems existing in the existing activated carbon desulfurization and denitrification process in the background technology, the utility model provides a flue atomization direct injection ammonia system in the activated carbon desulfurization and denitrification process.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process, comprising a primary adsorption tower and a secondary adsorption tower, a sintering flue gas pipeline is connected to the flue gas inlet of the primary adsorption tower, and a booster fan is arranged thereon as a flue gas conveying device, the flue gas outlet of the primary adsorption tower is connected to the flue gas inlet of the secondary adsorption tower through a connecting pipeline, the flue gas outlet of the secondary adsorption tower is connected to the chimney through an emptying pipeline, and a first ammonia branch pipeline connected to the ammonia main pipeline is connected to the main ammonia branch pipeline through a main ammonia branch pipeline. The pump is connected to the second ammonia branch pipeline, and the second ammonia branch pipeline is divided into a third ammonia branch pipeline and a fourth ammonia branch pipeline. The fourth ammonia branch pipeline serves as the ammonia source of the existing activated coke desulfurization and denitrification process. The third ammonia branch pipeline is connected to the first inlet of the distribution cabinet, and the nitrogen pipeline is connected to the second inlet of the distribution cabinet. The distribution cabinet distributes the single-channel nitrogen and ammonia water into sixteen channels, and each channel of nitrogen and ammonia water is connected to a dual-fluid atomizing spray gun through a spraying pipeline group. The sixteen dual-fluid atomizing spray guns are divided into four groups and arranged around the flue gas outlet of the first-level adsorption tower.

[0006] As a further supplement to the above technical solution, a reflux pipe and a first pressure gauge are respectively provided on the second ammonia water branch pipe, the reflux pipe is connected to the ammonia water tank, and an electric reflux valve is provided on the reflux pipe. The electric reflux valve and the first pressure gauge are interlockedly controlled through the on-site DCS control system, that is, when the outlet pressure of the ammonia water pump reaches 0.4MPa, the electric reflux valve automatically adjusts to open and maintains a constant pressure.

[0007] As a further supplement to the above technical solution, an electric safety valve is arranged on the second ammonia branch pipeline. The electric safety valve is interlocked with the adsorption temperature and the ammonia pressure value through the on-site DCS control system. That is, when any temperature point of the two adsorption towers reaches 150 degrees and the ammonia alarm value reaches 50ppm, the quick-cut valve automatically cuts off the supply of ammonia.

[0008] As a further explanation and limitation of the above technical solution, the fourth ammonia water branch pipe is connected to the first inlet of the evaporator, and a first manual control valve is arranged on the pipe. The steam branch pipe connected to the steam main pipe is connected to the second inlet of the evaporator, and a second manual control valve is arranged on the pipe. The outlet of the evaporator is connected to the first inlet of the mixer through the first ammonia evaporation pipe, the air supply pipe is connected to the second inlet of the mixer, and a dilution fan is arranged on the pipe. The outlet of the mixer is connected to the ammonia evaporation inlet of the secondary adsorption tower through the second ammonia evaporation pipe to provide the required ammonia evaporation for the denitrification process of the flue gas.

[0009] As a further supplement to the above technical solution, a first manual shut-off valve is provided on the third ammonia branch pipeline, and a second manual shut-off valve is provided on the nitrogen pipeline. The first manual shut-off valve and the second manual shut-off valve respectively cut off the supply of ammonia and nitrogen by shutting off the pipelines, so as to facilitate shutdown for inspection or equipment maintenance.

[0010] As a further supplement to the above technical solution, a flow meter is provided on the third ammonia branch pipeline, and a second pressure gauge is provided on the nitrogen pipeline. The flow meter facilitates on-site personnel to observe whether the ammonia supply is normal, and the second pressure gauge facilitates on-site personnel to observe whether the nitrogen supply meets the required conditions.

[0011] As a further supplement to the above technical solution, an ammonia bypass branch pipeline is arranged on the first ammonia branch pipeline, and a spare ammonia pump is arranged on the ammonia bypass branch pipeline. The spare ammonia pump is interlocked with the main ammonia pump through the on-site DCS control system.

[0012] As a further supplement to the above technical solution, the flow rate of the ammonia nozzle of the dual-fluid atomizing spray gun is much greater than the flow rate of the smoke.

[0013] Compared with the prior art, the utility model has the following advantages:

[0014] 1. The utility model realizes efficient utilization of ammonia water by directly spraying ammonia through flue atomization. Since the flow rate of the ammonia water nozzle is designed to be greater than 60m / s, which is far greater than the flow rate of flue gas, this high speed difference makes the atomized ammonia water and flue gas mix more evenly, greatly improving the degree of mixing. This design not only optimizes the consumption of ammonia water, but also enhances the denitrification effect, so that the denitrification rate reaches more than 83%.

[0015] 2. The utility model further improves the design of the entire system by adding shut-off valves, instruments, and ammonia pumps. The shut-off valve is convenient for cutting off the supply of ammonia and nitrogen during shutdown or equipment maintenance, ensuring the safety of the system. The flow meter and pressure gauge are convenient for on-site personnel to observe the supply of ammonia and nitrogen in real time to ensure stable system operation. The interlocking control design of the backup ammonia pump and the main ammonia pump further enhances the reliability and stability of the system.

[0016] 3. The utility model can automatically cut off the supply of ammonia water when the temperature of the adsorption tower is too high or the ammonia pressure is abnormal through the setting of the electric safety valve, thus avoiding the occurrence of safety accidents. The setting of the reflux pipeline and the electric reflux valve can automatically adjust the outlet pressure of the ammonia water pump when it is too high, maintain a constant pressure, and further ensure the safe operation of the modified activated coke desulfurization and denitrification process.

[0017] 4. The ammonia consumption of the flue atomization direct injection ammonia mode adopted by the utility model is reduced by 0.08 tons / day compared with the ammonia heating vaporization mode, and the economic benefits are remarkable. The response speed and adjustment accuracy are high, the denitrification rate reaches more than 83%, the maintenance cost is low, it is safe and stable, and the operation is reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the principle structure diagram of the flue atomization direct injection ammonia system of the utility model;

[0019] Figure 2 It is the layout diagram of the dual-fluid atomizing spray gun in the utility model.

[0020] In the figure: the first-stage adsorption tower is 1, the second-stage adsorption tower is 2, the booster fan is 3, the chimney is 4, the main ammonia water pump is 5, the distribution cabinet is 6, the first manual shut-off valve is 7, the second manual shut-off valve is 8, the standby ammonia water pump is 9, the second pressure gauge is 10, the flow meter is 11, the electric reflux valve is 12, the electric safety valve is 13, the first pressure gauge is 14, the evaporator is 15, the mixer is 16, the dilution fan is 17, the first manual control valve is 18, the second manual control valve is 19, and the dual-fluid atomizing spray gun is 20.

[0021] The sintering flue gas pipeline is 100, the connecting pipeline is 200, the emptying pipeline is 300, the first ammonia branch pipeline is 400, the second ammonia branch pipeline is 401, the third ammonia branch pipeline is 402, the fourth ammonia branch pipeline is 403, the bypass branch pipeline is 404, the reflux pipeline is 405, the nitrogen pipeline is 406, the spraying pipeline group is 500, the steam branch pipeline is 600, the first ammonia distillation pipeline is 700, the air supply pipeline is 800, and the second ammonia distillation pipeline is 900. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical solution of the utility model, the following Figure 1 and 2 ,According to the on-site transformation implementation process, we further illustrate the utility model through three embodiments. Embodiment 1

[0023] As attached Figure 1 and 2As shown, a flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process includes a primary adsorption tower 1 and a secondary adsorption tower 2. A sintering flue gas pipeline 100 is connected to the flue gas inlet of the primary adsorption tower 1, and a booster fan 3 is arranged thereon as a flue gas conveying device. The flue gas outlet of the primary adsorption tower 1 is connected to the flue gas inlet of the secondary adsorption tower 2 through a connecting pipeline 200, and the flue gas outlet of the secondary adsorption tower 2 is connected to a chimney 4 through an emptying pipeline 300. A first ammonia branch pipeline 400 connected to the ammonia main pipeline is connected to the main ammonia pump 5 through a main ammonia pump 5. The second ammonia branch pipe 401 is connected, and the second ammonia branch pipe 401 is divided into a third ammonia branch pipe 402 and a fourth ammonia branch pipe 403. The third ammonia branch pipe 402 is connected to the first inlet of the distribution cabinet 6, and the nitrogen pipe 406 is connected to the second inlet of the distribution cabinet 6. The distribution cabinet 6 distributes the single-channel nitrogen and ammonia water into sixteen channels, and each channel of nitrogen and ammonia water is connected to the double-fluid atomizing spray gun 20 through the spray pipe group 500. The sixteen double-fluid atomizing spray guns 20 are arranged in four groups around the flue gas outlet of the first-level adsorption tower 1. It should be noted that the single double-fluid atomizing spray gun 20 uses a flow range of 30-80L / h, and the pressure of ammonia water and compressed air at the inlet of the spray gun is between 0.3MPa and 0.6MPa. The ammonia water spray velocity from the nozzle is greater than 60m / s, which is much greater than the flue gas flow velocity. The high speed difference between the two is used to improve the mixing degree of atomized ammonia water and flue gas. The ammonia main pipe and each branch pipe are equipped with flow and pressure detection, which can effectively determine whether the spray gun is blocked or has other faults. When an abnormality occurs in a spray gun line, the flow of other spray guns can be adjusted to meet production needs. In this way, the conditions for online inspection and replacement of abnormal lines can be met at any time, and other lines can also be flexibly adjusted according to on-site needs. The above implementation parameter design is not the only option for this embodiment. Those skilled in the art can independently select and adjust according to actual conditions to achieve the best final denitrification effect.

[0024] In this embodiment, the existing activated coke desulfurization and denitrification process mainly includes the components of evaporator 15, mixer 16, dilution fan 17 and two manual control valves. Its specific implementation scheme: the fourth ammonia branch pipeline 403 is connected to the first inlet of the evaporator 15, and a first manual control valve 18 is arranged on its pipeline, the steam branch pipeline 600 connected to the steam main pipeline is connected to the second inlet of the evaporator 15, and a second manual control valve 19 is arranged on its pipeline, the outlet of the evaporator 15 is connected to the first inlet of the mixer 16 through the first ammonia evaporation pipeline 700, the air supply pipeline 800 is connected to the second inlet of the mixer 16, and a dilution fan 17 is arranged on its pipeline, and the outlet of the mixer 16 is connected to the ammonia evaporation inlet of the secondary adsorption tower 2 through the second ammonia evaporation pipeline 900, so as to provide the required ammonia evaporation for the denitration process of the flue gas.

[0025] The utility model is modified on the basis of the existing activated coke desulfurization and denitrification process, and adopts the mode of direct ammonia spraying through flue atomization. The flow rate of ammonia water nozzle is greater than 60m / s, which is much greater than the flue gas flow rate. The speed difference improves the mixing degree of atomized ammonia water and flue gas, and at the same time, the heat of the flue gas itself is used to heat the ammonia water to form atomized ammonia vapor in the flue, without the need for an additional heat source. The flue atomization direct ammonia spraying system can not only replace the original denitrification ammonia spraying process, but also use the heat of the flue gas itself at the outlet of the first-level adsorption tower to evaporate the atomized ammonia water, further reducing the intermediate link of ammonia water vaporization, and can obtain faster response speed and regulation accuracy. Embodiment 2

[0026] In order to ensure the normal operation of the flue atomization direct injection ammonia system, we have improved the defects in the entire system design process from three aspects by adding shut-off valves, instruments, and ammonia water pumps. Figure 1 The specific plan is as follows:

[0027] First, a first manual shut-off valve 7 is provided on the third ammonia branch pipeline 402, and a second manual shut-off valve 8 is provided on the nitrogen pipeline 406. The first manual shut-off valve 7 and the second manual shut-off valve 8 respectively cut off the supply of ammonia and nitrogen by shutting off the pipelines, so as to facilitate shutdown inspection or equipment maintenance.

[0028] Second, a flow meter 11 is provided on the third ammonia branch pipeline 402, and a second pressure gauge 10 is provided on the nitrogen pipeline 406. The flow meter 11 is convenient for on-site personnel to observe whether the ammonia supply is normal, and the second pressure gauge 10 is convenient for on-site personnel to observe whether the nitrogen supply meets the required conditions.

[0029] Third, an ammonia bypass branch pipeline 404 is provided on the first ammonia branch pipeline 400 , and a standby ammonia pump 9 is provided on the ammonia bypass branch pipeline 404 . The standby ammonia pump 9 is interlocked with the main ammonia pump 5 through the on-site DCS control system. Embodiment 3

[0030] In order to ensure the safe operation of the entire activated coke desulfurization and denitrification process after the transformation, we take two measures in the subsequent operation: On the one hand, an electric safety valve 13 is set on the second ammonia branch pipeline 401, and the electric safety valve 13 is linked with the adsorption temperature and ammonia pressure value through the on-site DCS control system, that is, when any temperature point of the two adsorption towers reaches 150 degrees and the ammonia alarm value reaches 50ppm, the quick-cut valve automatically cuts off the supply of ammonia. On the other hand, a reflux pipeline 405 and a first pressure gauge 14 are respectively set on the second ammonia branch pipeline 401, and the reflux pipeline 405 is connected to the ammonia tank. An electric reflux valve 12 is set on the reflux pipeline 405, and the electric reflux valve 12 and the first pressure gauge 14 are linked through the on-site DCS control system, that is, when the outlet pressure of the ammonia pump reaches 0.4MPa, the electric reflux valve 12 automatically adjusts to open and keeps the pressure constant.

[0031] After the flue atomization direct injection ammonia system was put into use, practice showed that the ammonia consumption of the flue atomization direct injection mode was 0.08 tons / day less than that of the ammonia heating vaporization mode, and the denitrification rate reached more than 83%.

[0032] The above shows and describes the main features and advantages of the utility model. For those skilled in the art, it is obvious that the specific implementation of the utility model is not limited to the details of the above exemplary embodiments, and the creative ideas and design ideas of the utility model can be realized in other specific forms without departing from the spirit or basic features of the utility model, which should be equivalent to the protection scope disclosed in the technical solution of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, so it is intended to include all changes that fall within the meaning and scope of the equivalent elements of the claims in the utility model.

[0033] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process, comprising a primary adsorption tower (1) and a secondary adsorption tower (2), a sintering flue gas pipeline (100) connected to the flue gas inlet of the primary adsorption tower (1), and a booster fan (3) arranged thereon as a flue gas conveying device, the flue gas outlet of the primary adsorption tower (1) connected to the flue gas inlet of the secondary adsorption tower (2) through a connecting pipeline (200), and the flue gas outlet of the secondary adsorption tower (2) connected to a chimney (4) through an exhaust pipeline (300), characterized in that: A first ammonia branch pipeline (400) connected to the ammonia main pipeline is connected to a second ammonia branch pipeline (401) through a main ammonia pump (5). The second ammonia branch pipeline (401) is divided into a third ammonia branch pipeline (402) and a fourth ammonia branch pipeline (403). The fourth ammonia branch pipeline (403) serves as an ammonia source for the existing activated coke desulfurization and denitrification process. The third ammonia branch pipeline (402) is connected to a first inlet of a distribution cabinet (6). A nitrogen pipeline (406) is connected to a second inlet of the distribution cabinet (6). The distribution cabinet (6) distributes a single nitrogen and ammonia into sixteen nitrogen and ammonia channels, each of which is connected to a dual-fluid atomizing spray gun (20) through a spraying pipeline group (500). The sixteen dual-fluid atomizing spray guns (20) are arranged in four groups around the flue gas outlet of the first-level adsorption tower (1).

2. The flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process according to claim 1 is characterized by: A reflux pipeline (405) and a first pressure gauge (14) are respectively provided on the second ammonia water branch pipeline (401); the reflux pipeline (405) is connected to the ammonia water tank; an electric reflux valve (12) is provided on the reflux pipeline (405); the electric reflux valve (12) and the first pressure gauge (14) are interlockedly controlled via an on-site DCS control system, i.e., when the outlet pressure of the ammonia water pump reaches 0.4 MPa, the electric reflux valve (12) is automatically adjusted to open and keep the pressure constant.

3. The flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process according to claim 2 is characterized by: An electric safety valve (13) is provided on the second ammonia branch pipeline (401). The electric safety valve (13) is interlocked with the adsorption temperature and the ammonia pressure value through the on-site DCS control system, that is, when any temperature point of the two adsorption towers reaches 150 degrees and the ammonia alarm value reaches 50ppm, the quick-cut valve automatically cuts off the supply of ammonia.

4. A flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process according to any one of claims 1 to 3, characterized in that: The fourth ammonia branch pipe (403) is connected to the first inlet of the evaporator (15), and a first manual control valve (18) is arranged on the pipe. The steam branch pipe (600) connected to the steam main pipe is connected to the second inlet of the evaporator (15), and a second manual control valve (19) is arranged on the pipe. The outlet of the evaporator (15) is connected to the first inlet of the mixer (16) through the first ammonia evaporation pipe (700). The air supply pipe (800) is connected to the second inlet of the mixer (16), and a dilution fan (17) is arranged on the pipe. The outlet of the mixer (16) is connected to the ammonia evaporation inlet of the secondary adsorption tower (2) through the second ammonia evaporation pipe (900), so as to provide the required ammonia evaporation for the denitration process of the flue gas.

5. The flue atomization direct injection ammonia system in the activated carbon desulfurization and denitrification process according to claim 4 is characterized by: A first manual shut-off valve (7) is provided on the third ammonia branch pipeline (402), and a second manual shut-off valve (8) is provided on the nitrogen pipeline (406). The first manual shut-off valve (7) and the second manual shut-off valve (8) cut off the supply of ammonia and nitrogen respectively by shutting off the pipelines, thereby facilitating shutdown for inspection or equipment maintenance.

6. The flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process according to claim 4 is characterized by: A flow meter (11) is provided on the third ammonia branch pipeline (402), and a second pressure gauge (10) is provided on the nitrogen pipeline (406). The flow meter (11) facilitates on-site personnel to observe whether the ammonia supply is normal, and the second pressure gauge (10) facilitates on-site personnel to observe whether the nitrogen supply meets the required conditions.

7. A flue atomization direct injection ammonia system in an activated carbon desulfurization and denitrification process according to any one of claims 1 to 3 or any one of claims 5 to 6, characterized in that: An ammonia water bypass branch pipeline (404) is provided on the first ammonia water branch pipeline (400), and a standby ammonia water pump (9) is provided on the ammonia water bypass branch pipeline (404). The standby ammonia water pump (9) is interlocked with the main ammonia water pump (5) through an on-site DCS control system.

8. The flue atomization direct injection ammonia system in the activated carbon desulfurization and denitrification process according to claim 7 is characterized by: The flow rate of the ammonia water nozzle of the dual-fluid atomizing spray gun (20) is much greater than the flow rate of the smoke.

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