Reactor for controlling ammonia escape of high-dust flue gas

Abstract

The utility model relates to the technical field of flue gas purification, in particular to a reactor for controlling ammonia escape of high-dust flue gas, which is mounted in a denitration tower, flue gas sensors are arranged in a flue gas inlet flue and a flue gas outlet flue of the denitration tower, an ammonia spraying system is arranged in the flue gas inlet flue, a plurality of groups of catalysts are arranged in the denitration tower, and the ammonia spraying system is connected with the flue gas sensors. A soot blower is arranged above each catalyst; a heater is further arranged on a connecting pipeline between the soot blower and the external air source; an ash collecting assembly is also arranged at the bottom of the denitration tower; the reactor for controlling ammonia escape of high-dust flue gas is simple in overall structure, is modified according to an original denitration tower reactor, is small in occupied area, and solves the problem of high ammonia escape rate in actual denitration operation of a factory by utilizing soot blowing action and changing ammonia spraying flow and coordinating two denitration key nodes when an ammonia escape numerical value exceeds a standard.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas purification, and particularly relates to a reactor for controlling ammonia escape in high-dust flue gas. Background Art

[0002] In order to meet the requirements of GB4915-2013 "Emission Standard of Air Pollutants for Cement Industry" and the increasingly strict requirements of environmental protection authorities for the emission of air pollutants, a device that meets the requirements of industrial flue gas desulfurization and denitrification has become a key issue that must be solved for the normal production of enterprises.

[0003] The SCR selective catalytic reduction technology is a mature and efficient flue gas denitrification technology. In industry, 20% ammonia water is used as a reducing agent and is directly sprayed into the upstream flue of the SCR reactor through a spray gun. The fully mixed reducing agent and flue gas react under the action of the catalyst in the SCR reactor to remove NOx. The main reactions are:

[0004] 4NH3 + 4NO + O2 = 4N2 + 6H2O

[0005] 8NH3 + 6NO2 = 7N2 + 12H2O

[0006] The catalyst is the core of the SCR technology. Only when NH3 and NOx come into contact on the surface can NOx in the flue gas be effectively degraded. When the dust content in the flue gas is relatively high, such as in the denitrification reactor of a cement kiln flue gas, a layer of cement ash is extremely likely to cover the surface of the catalyst, inhibiting the occurrence of the catalytic reaction. At this time, the denitrification efficiency decreases. Technicians generally think that the denitrification reaction is insufficient due to insufficient ammonia water dosage. Therefore, the ammonia water input amount is increased. As a result, unreacted NH3 and excessive NH3 will escape from the end of the reactor, leading to secondary pollution of ammonia escape.

[0007] When the NOx discharge concentration is too high, or a large amount of ammonia escape occurs, ammonia escape will not only have a negative impact on air quality, but also cause equipment corrosion. In order not to affect the denitrification performance of the catalyst and ensure that sufficient redox reaction occurs between NH3 and NOx to reduce ammonia escape, it is crucial to control the ash cleaning and ash discharging systems. Content of the Utility Model

[0008] The purpose of the utility model is to provide a reactor for controlling ammonia escape in high-dust flue gas with simple equipment, low transformation cost, and rapid response to maintain dynamic balance.

[0009] To achieve the above purpose, the utility model provides the following technical solutions;

[0010] A reactor for controlling ammonia escape in high-dust flue gas. The reactor is installed in a denitration tower. Flue gas sensors are provided in both the inlet flue and the outlet flue of the denitration tower. A spray ammonia system is provided in the inlet flue. Multiple groups of catalysts are provided in the denitration tower, and a soot blower is provided above each catalyst; a heater is also provided on the connecting pipeline between the soot blower and an external gas source; a dust collection assembly is also provided at the bottom of the denitration tower.

[0011] Further, the spray ammonia system includes an ammonia water spray gun extending into the inlet flue, an ammonia supply pump for pumping ammonia water, and a regulating valve provided between the ammonia water spray gun and the ammonia supply pump;

[0012] Further, the soot blower is a sonic soot blower, and a solenoid valve and a control cabinet for adjustment are also provided between the soot blower and the heater.

[0013] Further, the dust collection assembly includes a dust collection hopper installed at the lower part of the denitration tower and an ash discharge zipper machine installed below the dust collection hopper.

[0014] Further, the ammonia supply points of the ammonia water spray gun are evenly distributed on the inner wall of the inlet flue;

[0015] Further, the ammonia water spray gun is a two-fluid atomizing nozzle;

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0017] When the present utility model works specifically, it also includes a control system. The control system is used to collect the data obtained by the flue gas sensor, convert it into a control signal after processing, and transmit it to the spray ammonia system and the soot blower; in the working state, the flue gas enters the inlet flue, flows through the multi-layer catalyst to react, the dust sinks and enters the dust collection assembly, and the treated flue gas is discharged through the outlet flue; when the catalyst surface is fouled, the flue gas sensor obtains that the pressure difference between the inlet and outlet of the denitration tower increases, and the discharge concentration of NOx increases, indicating that the ammonia escape deteriorates; the soot blower performs a gas blowing action on the catalyst, and the spray ammonia system increases the spray flow rate; until the data obtained by the flue gas sensor reaches below the set value.

[0018] This reactor for controlling ammonia escape in high-dust flue gas has a simple overall structure. It is transformed based on the original denitration tower reactor, and the equipment occupies a small area. When the ammonia escape value exceeds the standard, by using the blowing action and changing the spray ammonia flow rate, two key denitration nodes are coordinated, and the problem of high ammonia escape rate in the actual denitration operation of the factory is solved. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the overall structure of the present utility model; Detailed Embodiment

[0020] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0021] Referring to Figure 1 As shown, a reactor for controlling ammonia escape in high-dust flue gas is installed in a denitration tower. Flue gas sensors 10 are provided in both the inlet flue 2 and the outlet flue 11 of the denitration tower. A ammonia injection system is provided in the inlet flue 2. A plurality of groups of catalysts 3 are provided in the denitration tower, and a soot blower 6 is provided above each catalyst 3; a heater 9 is further provided on the connecting pipeline of the soot blower 6 and an external gas source; a dust collection assembly is further provided at the bottom of the denitration tower.

[0022] In actual use, it further includes a control system. The control system is used to collect the data obtained by the flue gas sensor 10, convert it into a control signal after processing, and transmit it to the ammonia injection system and the soot blower 6; in the working state, the flue gas enters the inlet flue 2, flows through the multi-layer catalyst to react, the dust sinks into the dust collection assembly, and the processed flue gas is discharged through the outlet flue 11; when the catalyst surface is fouled, the flue gas sensor 10 obtains that the pressure difference between the inlet and outlet of the denitration tower increases, and the discharge concentration of NOx increases, indicating that the ammonia escape deteriorates; the soot blower 6 performs a gas blowing action on the catalyst, and the ammonia injection system increases the injection flow rate; until the data obtained by the flue gas sensor 10 reaches below the set value.

[0023] The reactor for controlling ammonia escape in high-dust flue gas has a simple overall structure, is transformed based on the original denitration tower reactor, has a small floor area, and when the ammonia escape value exceeds the standard, it uses the blowing action and changes the ammonia injection flow rate to coordinate two key denitration nodes, solving the problem of high ammonia escape rate in the actual denitration operation of the factory.

[0024] In this embodiment, the ammonia injection system includes an ammonia water spray gun 1 extending into the inlet flue 2, an ammonia supply pump 4 for pumping ammonia water, and a regulating valve 5 provided between the ammonia water spray gun 1 and the ammonia supply pump 4; the ammonia injection system is located upstream of the denitration tower, the ammonia water spray gun 1 is installed inside the inlet flue 2, and there is a certain distance from the surface of the catalyst 3. The regulating valve 5 is an electric control regulating valve, which can be accurately adjusted according to the data feedback from the flue gas sensor 10 to reasonably control the ammonia injection flow rate of the ammonia water spray gun 1.

[0025] In this embodiment, the soot blower 6 is a sonic soot blower. A solenoid valve 7 and a control cabinet 8 are also provided between the soot blower 6 and the heater 9. A set of soot blowers 6 is installed on the upper surface of each layer of catalyst 3. The gas source of the soot blower 6 is compressed air, and its opening and closing are controlled by the solenoid valve 7. The equipped control cabinet 8 can remotely control the starting frequency. The solenoid valve 7 is electrically connected to the control system. If the dust content in the flue gas system is high, resulting in frequent purging, to ensure that the temperature in the reactor is maintained within the temperature range suitable for the SCR catalyst reaction, a small heater 9 can be installed on the air supply pipeline of the sonic soot blower 6 to heat the gas to 200°C and then introduce it into the reactor to purge the catalyst layer.

[0026] In this embodiment, the ash collection assembly includes an ash collection hopper 12 installed at the lower part of the denitration tower and an ash discharge chain conveyor 13 installed below the ash collection hopper 12.

[0027] In this embodiment, the ammonia supply points of the ammonia water spray gun 1 are evenly distributed on the inner wall of the inlet flue 2.

[0028] In this embodiment, the ammonia water spray gun 1 is a two-fluid atomizing nozzle.

[0029] In this embodiment, the flue gas sensor 10 is a CEMS flue gas analysis system. The values obtained by the flue gas sensor 10 generate control signals and are fed back to the upstream regulating valve 5 and the solenoid valve 7 to control the ammonia water spray gun and the soot blower. When the value is higher than the set value, the solenoid valve 7 acts first, and the sonic soot blowers 6 of each layer of catalyst clean the ash in sequence. After a certain command time, it resumes the original ash cleaning frequency. When the pressure difference decreases, it indicates that the ash has been cleaned up and the pores of the catalyst 3 module have been cleaned up. If at this time the NOx concentration and ammonia slip in the flue gas sensor 10 both decrease to the emission standards, there is no need to issue a flow regulation command for the ammonia water regulating valve 5. If both are still higher than the standards at this time, control the regulating valve 5 to increase the injection flow. If any one of the values is higher than the emission standard, still increase the ammonia water injection flow.

[0030] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the scope defined by the spirit of the present invention.

Claims

1. A reactor for controlling ammonia escape from high-dust flue gas, the reactor being installed in a denitrification tower, characterized in that: A flue gas sensor (10) is provided at both the smoke inlet duct (2) and the smoke outlet duct (11) of the denitrification tower, and an ammonia injection system is provided in the smoke inlet duct (2). A plurality of groups of catalysts (3) are provided in the denitrification tower, and a soot blower (6) is provided above each of the catalysts (3); a heater (9) is also provided on the connection pipeline between the soot blower (6) and an external air source; and a soot collecting component is also provided at the bottom of the denitrification tower.

2. A reactor for controlling ammonia escape from high-dust flue gas according to claim 1, characterized in that: The ammonia spraying system comprises an ammonia water spray gun (1) extending into a smoke inlet duct (2), an ammonia supply pump (4) for pumping ammonia water, and a regulating valve (5) arranged between the ammonia water spray gun (1) and the ammonia supply pump (4).

3. A reactor for controlling ammonia escape from high-dust flue gas according to claim 1, characterized in that: The soot blower (6) is a sonic soot blower, and a solenoid valve (7) and a control cabinet (8) for adjusting are also provided between the soot blower (6) and the heater (9).

4. A reactor for controlling ammonia escape from high-dust flue gas according to claim 1, characterized in that: The ash collecting component comprises an ash collecting hopper (12) installed at the lower part of the denitration tower, and an ash discharging zipper (13) installed below the ash collecting hopper (12).

5. A reactor for controlling ammonia escape from high-dust flue gas according to claim 2, characterized in that: The ammonia supply points of the ammonia spray gun (1) are evenly distributed on the inner wall of the smoke inlet duct (2).

6. A reactor for controlling ammonia escape from high-dust flue gas according to claim 5, characterized in that: The ammonia water spray gun (1) is a dual-fluid atomizing nozzle.

7. A reactor for controlling ammonia escape from high-dust flue gas according to claim 5, characterized in that: The flue gas sensor (10) is a CEMS flue gas analysis system.

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