WO2018068548A1

WO2018068548A1 - Oxidation method for sintering flue gas denitrification and system

Info

Publication number: WO2018068548A1
Application number: PCT/CN2017/093399
Authority: WO
Inventors: 胡小吐; 刘勇; 钟璐
Original assignee: 广东佳德环保科技有限公司
Priority date: 2016-10-12
Filing date: 2017-07-18
Publication date: 2018-04-19
Also published as: CN106422722A

Abstract

An oxidation method for sintering flue gas denitrification. The method comprises: using an ozone plasma generator to discharge electricity into an oxygen source and generate plasma free radicals; and the plasma free radicals transforming NO in a flue gas into a nitrogen oxide with a higher valence state. The volume of the plasma free radicals produced is controlled according to the concentration of the flue gas. In a mixture of the oxygen source and a NO_x-containing flue gas, the mass ratio of NO to NO₃ is 0.8-1.5:1. The plasma free radical production volume of the ozone plasma generator is 6-12 kg/h for 30,000-50,000 Nm³/h of the NO_x-containing flue gas, realizing rapid oxidation and high denitrification efficiency. Using the ozone plasma for denitrification can achieve a higher NO_x denitrification rate and up to 98% NO_x removal rate. Further provided is a sintering flue gas denitrification system. The denitrification system comprises: a detection device, a flue gas intake device, an ozone plasma generator, a controller, a denitrification device, a spraying device, a desulfurization tower, and a flue gas discharging device. The controller is connected to the detection device, the flue gas intake device, and the ozone plasma generator. The denitrification device is connected to the ozone plasma generator and the flue gas intake device. The desulfurization tower is internally provided with the spraying device. The denitrification device is connected to the desulfurization tower. The flue gas discharging device is provided at a top end of the desulfurization tower.

Description

Oxidation sintering flue gas denitration method and system

Technical field

The invention belongs to the field of flue gas treatment, and particularly relates to an oxidation method sintering flue gas denitration method and system.

Background technique

At present, the internationally mature denitration processes mainly include selective catalytic reduction (SCR), non-selective catalytic reduction (SNCR) and activated carbon. The denitrification efficiency of selective catalytic reduction can reach more than 90%, instead of selection. The denitrification efficiency of the catalytic reduction method and the activated carbon method is relatively low, usually around 40%.

The oxidation process is used to sinter flue gas denitration, which essentially oxidizes nitrogen oxides in the flue gas into high-valence substances that are easily absorbed by the spray liquid. CN102764574A discloses a desulfurization and denitration method for streamer discharge plasma radical injection of flue gas, which comprises the following steps: 1) discharging oxygen or air by a streamer discharge plasma reactor to generate plasma radicals; 2) The gas containing the plasma radical is injected into the flue, and is mixed with the flue gas containing sulfur oxides and nitrogen oxides, and the plasma radical converts the sulfur oxides and nitrogen oxides in the flue gas into oxides of higher valence; 3) The flue gas from the previous step is sent to the desulfurization tower for cyclic spray absorption, so that sulfur oxides and nitrogen oxides enter the liquid phase; 4) the flue gas absorbed by the circulating spray is discharged through the chimney after defogging. CN102764573A discloses a technical solution similar to the above-mentioned technique, in which a radical is used to oxidize nitrogen oxides into a high-valent substance and then absorbed by a spray liquid. However, the above two solutions do not solve the problem of high-efficiency absorption according to the specific emission situation of the factory, and do not solve how to effectively use the free radicals to make full use of them to oxidize nitrogen oxides more effectively.

CN102274680A discloses a method for synthesizing flue gas desulfurization, denitrification and defogging by streamer discharge ammonia method, which comprises the following steps: 1) boiler flue gas containing sulfur dioxide and nitrogen oxides, and after being dusted, is sent to a streamer discharge denitration reactor ( 1); 2) the flue gas after the streamer discharge denitration reactor (1) enters the desulfurization tower (2) and is discharged from the top outlet of the desulfurization tower; 3) the flue gas exiting the top outlet of the desulfurization tower passes through the electric mist eliminator ( 3) Defogging purification to send chimney emissions. The specification of the patent discloses that more than 95% of the demon gas nitrogen oxides are NO, and the principle of generating free radicals by streamer discharge and the principle of desulfurization and deamination are disclosed, but the radicals required for specific emissions of the plant are not solved, and The effects of emissions, free radicals, voltage and other parameters on denitration efficiency are not disclosed, that is, the effect of synergistic effects of various factors on the efficiency of denitrification is not disclosed.

CN101961596A discloses a light one oxygen radical oxidative desulfurization active particles into the flue gas denitration process, the oxygen is injected into the flue active particles with water to form a hydroxyl radical · OH, in the flue gas and oxidizing SO _2, NO _X. The principle is also the oxidation of flue gas oxidizing sulfur and nitrogen oxides, but in this patent also does not solve the problem of improving the denitration efficiency for specific plant conditions.

Summary of the invention

In order to solve the above problems, how to adjust the ozone amount and other parameters to improve the denitration efficiency according to the difference in factory emissions, the present invention provides an oxidation method sintering flue gas denitration method, comprising the following steps:

1) discharging an oxygen source by using an ozone plasma generator device to generate a plasma radical;

2) detecting intake air inlet of the flue gas-containing flue gas concentration of NO _x and amount of ions in order to control the concentration of free radicals and the like;

Radical oxygen ion source 3) containing the flue gas and the like containing mixed with the NO _x, the NO in the flue gas converted to a higher valence nitrogen oxides;

The concentration of NO _x -containing flue gas is 280-350mg / Nm ^3, the x = 1 or 2; the NO flue gas mass ratio accounted for greater than 95%; the plasma radical comprising O _3, O, e, the mass ratio of the O _{3 to} the oxygen source of the plasma radical is greater than 8%;

Said step 3) mixing the flue gas mixture containing an oxygen source of NO _x in the NO and O ₃ mass ratio is 0.8-1.5: 1.

Preferably, the denitration method preferably comprises the following steps:

4) sending the flue gas of the step 3) to the desulfurization tower for circulating spray absorption, so that the nitrogen oxides enter the liquid phase;

5) The flue gas absorbed by the circulating spray is discharged through the chimney after defogging.

Preferably, the plasma generator means ozone plasma radical production was 6-12kg / h, the flue gas containing the NO _x 30000-50000Nm ³ / h.

Preferably, the ozone plasma generator device comprises an ozone generator having an operating voltage of 5 kV and a power supply frequency of 800-1200 Hz.

Preferably, the step 3) and an oxygen source in the mixture containing flue gas mixture of NO _x in the NO and O ₃ mass ratio is 30: 1.

Preferably, the flue gas containing NO ₂ of NO _x in flue gas mass ratio accounts for 1-4%, accounting for the mass of flue gas NO ratio of 96-99%.

Preferably, the flue gas containing NO ₂ of NO _x in flue gas mass ratio accounted for 2% of the flue gas mass ratio of NO accounts for 98%.

Preferably, the absorbing liquid used for circulating spray absorption is an alkaline absorbing liquid.

Preferably, the alkaline absorption liquid comprises ammonia water, sodium hydroxide, calcium hydroxide or calcium oxide.

The present invention also provides a denitration system using the above method, comprising a detection device, a flue gas intake device, an ozone plasma generator device, a controller, a denitration device, a sprinkler device, a desulfurization tower device, and an exhaust gas discharge device; The controller is connected to the detecting device and the flue gas inlet device and the ozone plasma generator device; the denitration device is connected to the ozone plasma generator device and the flue gas inlet device, and the desulfurization tower device is provided with a sprinkler device, The denitration device is connected to the desulfurization tower device, and the exhaust gas discharge device is disposed at the top of the desulfurization tower device.

The detecting device is configured to detect a concentration of a smoke component at a flue gas inlet and an outlet of the flue gas inlet device and an O ₃ concentration at an inlet and outlet of the ozone plasma generator device, and the NO concentration data transmitted by the controller through the detecting device The concentration of the O ₃ output in the ozone plasma generator unit is controlled.

Preferably, the ozone plasma generator device includes an ozone generator and a cooling water system; the ozone generator includes a reactor body, a fan, an ozone uniform doping device, and a discharge tube; and the cooling water system is disposed in the discharge The outer wall of the tube; the ozone uniform distribution device adopts a multi-point equalization gas.

Preferably, the cooling water system comprises a plate heat exchanger, a circulating water pump, an expansion tank, a base and a meter, and the plate heat exchanger and the expansion tank are integrally fixed on the base.

Preferably, the fan is a mixed flow axial flow fan, and the power of the fan is 18.5 kW.

Preferably, the cooling water system is provided with a flow switch, a temperature transmitter, and an alarm system.

The beneficial effects of the invention:

(1) The oxidation rate is fast and the denitration efficiency is high; the ozone denitration can obtain a higher NOx removal rate, the NOx removal rate can reach 98%, the NO oxidation rate is high, and the O ₃ utilization rate is high;

(2) No catalyst required, no reaction temperature requirement;

(3) Ozone is added to the flue before denitration, the installation is simple, the time of stopping the furnace is short, the docking time of the furnace is short, and the normal production is not affected; the existing desulfurization tower is used for absorption, and the desulfurization facilities are not affected, and the desulfurization is realized. Denitrification integration, low investment, small footprint, can adapt to higher environmental requirements.

(4) The O ₃ addition is controllable, and the input amount of O ₃ is adjusted according to the concentration of the flue gas component, and the residual unreacted O ₃ is absorbed and removed in the desulfurization tower without leakage of O ₃ .

DRAWINGS

Figure 1 is a flow chart of the apparatus of the present invention.

detailed description

The specific embodiments of the present invention are further described below:

Example 1

The denitration system of the present invention comprises a detection device, a flue gas intake device, an ozone plasma generator device, a controller, a denitration device, a sprinkler device, a desulfurization tower device, and an exhaust gas discharge device; and the denitration device is connected to an ozone plasma generator a device and a flue gas inlet device, wherein the desulfurization tower device is provided with a sprinkler device, the denitration device is connected to a desulfurization tower device, the exhaust gas discharge device is disposed at a top end of the desulfurization tower device; and the detecting device is configured to detect flue gas a concentration of the smoke component at the inlet and outlet of the flue gas of the air intake device and an O ₃ concentration at the inlet and outlet of the ozone plasma generator device, the controller connecting the detecting device and the flue gas inlet device, the ozone plasma generator device, The controller controls the concentration of the O ₃ output in the ozone plasma generator device by detecting the NO concentration data transmitted by the device.

The invention provides an oxidation sintering flue gas denitration method, comprising the following steps:

) Concentration in flue gas detecting gas containing the intake air inlet of NO _x, a concentration of the controller in order to control the amount of ionic free radicals and the like;

4) The flue gas from the previous step is sent to the desulfurization tower for cyclic spray absorption, so that the nitrogen oxides enter the liquid phase;

5) The flue gas absorbed by the circulating spray is discharged through the chimney after defogging;

The concentration of NO _x -containing flue gas is 300mg / Nm ^3, the x = 1 or 2; mass ratio of the flue gas NO accounts for 96%; mass ratio of NO ₂ accounted for 3% of the flue gas, the The plasma radical includes O ₃ , O, e, and the mass ratio of the O _{3 to} the oxygen source of the plasma radical is greater than 8%;

The plasma ozone generator means radicals in the plasma production of 10kg / h, the flue gas containing the NO _x 40000Nm ³ / h. The ozone plasma generator device includes an ozone generator having an operating voltage of 5 kV and a power supply frequency of 800-1200 Hz.

Said step 2) in the flue gas and an oxygen source containing the mixture of NO _x, i.e., the mixture entering the denitration apparatus NO and O ₃ mass ratio is 30: 1.

After the flue gas and ozone pass through the denitration device, the NO oxidation conversion rate is 90%, and the ozone utilization rate is 80%;

The absorption liquid used for the circulation spray absorption is an alkaline absorption liquid, and the alkaline absorption liquid includes ammonia water, sodium hydroxide, calcium hydroxide, and calcium oxide. Flue gas after the oxidation and ozone after desulfurization tower apparatus, NO ₂ absorption efficiency was 98% and the concentration of NO _x from the tail gas is discharged out of the apparatus 6mg / Nm ^3, the overall removal efficiency of NO _x 98%.

Example 2

The second embodiment adopts the denitration system and the denitration method of the first embodiment, and the difference is the smoke entering concentration and the O ₃ amount, as follows:

The concentration of NO _x -containing flue gas is 350mg / Nm ^3, the x = 1 or 2; the NO flue gas mass ratio accounted for 97%; NO ₂ ratio of flue gas mass accounted for 2.5% of the The plasma radical includes O ₃ , O, e, and the mass ratio of the O _{3 to} the oxygen source of the plasma radical is 12%;

The plasma ozone generator means radicals in the plasma production of 12kg / h, the flue gas containing the NO _x 50000Nm ³ / h. The ozone plasma generator device includes an ozone generator having an operating voltage of 5 kV and a power supply frequency of 800-1200 Hz.

Said step 2) in the flue gas and an oxygen source containing the mixture of NO _x, i.e., the mixture entering the denitration apparatus NO and O ₃ mass ratio is 20: 1.

After the flue gas and ozone pass through the denitration device, the NO oxidation conversion rate is 92%, and the ozone utilization rate is 82%;

The absorption liquid used for the circulation spray absorption is an alkaline absorption liquid, and the alkaline absorption liquid includes ammonia water, sodium hydroxide, calcium hydroxide, and calcium oxide. Flue gas after the oxidation and ozone after desulfurization tower apparatus, NO ₂ absorption efficiency of 97%, the concentration of NO _x from the exhaust gas is discharged out of the apparatus of 11mg / Nm ^3, the overall removal efficiency of NO _x 96%.

Comparative example 1

Using CN102274680A of desulfurization and denitrification method, enters the flue gas inlet CN102274680A the same as in Example 1 equivalent flue embodiment desulfurization and denitrification, the detection denitrification efficiency, It was found from the concentration of NO _x Comparative Example 1 exhaust gas removing apparatus of excluded 80mg / Nm ^3, the overall removal efficiency of only 73% of NO _x. This is because the amount of ozone is not limited in the method of CN102274680A, and there is no reasonable quantification according to the specific factory smoke concentration. The streamer discharger generates more radicals, but the effect on NOx. The effect of Embodiment 1 of the present invention is not good.

CN102764574A and CN102764573A disclose only a simple method, which is not applicable to the factory flue gas conditions in Examples 1 and 2, and is inferior in denitration efficiency to Examples 1 and 2.

Comparative example 2

Comparative Example 2 is different from Example 1 in that the controller is not used to adjust the plasma radical production according to the concentration of the flue gas inlet amount, that is, the amount of O ₃ cannot be provided according to the NO concentration, and the denitration system of Comparative Example 2 is not provided. The controller controls the ozone plasma generator device; the denitration system of Comparative Example 2 is applied to the flue gas denitration method, and it is found that according to the difference of the flue gas import amount, if the amount of O ₃ is not adjusted, the NO oxidation conversion rate is reduced to 70%. ozone utilization to 65% and the total efficiency of removal of NO _x of 65%, in particular in Table 1 below.

Table 1

Variations and modifications of the above-described embodiments may also be made by those skilled in the art in light of the above disclosure. Therefore, the present invention is not limited to the specific embodiments disclosed and described, and the modifications and variations of the invention are intended to fall within the scope of the appended claims. In addition, although specific terms are used in the specification, these terms are merely for convenience of description and do not limit the invention.

Claims

An oxidation method sintering flue gas denitration method, characterized in that the method comprises the following steps:

1) discharging an oxygen source by using an ozone plasma generator device to generate a plasma radical;

2) detecting intake air inlet of the flue gas-containing flue gas concentration of NO x and amount of ions in order to control the concentration of free radicals and the like;

Radical oxygen ion source 3) containing the flue gas and the like containing mixed with the NO x, the NO in the flue gas converted to a higher valence nitrogen oxides;

The concentration of NO x -containing flue gas is 280-350mg / Nm 3, the x = 1 or 2; the NO flue gas mass ratio accounted for greater than 95%; the plasma radical comprising O 3, O, e, the mass ratio of the O 3 to the oxygen source of the plasma radical is greater than 8%;

Said step 3) mixing the flue gas mixture containing an oxygen source of NO x in the NO and O 3 mass ratio is 0.8-1.5: 1.
The method of oxidizing sintering flue gas denitration according to claim 1, wherein the denitration method comprises the following steps:

4) sending the flue gas of the step 3) to the desulfurization tower for circulating spray absorption, so that the nitrogen oxides enter the liquid phase;

5) The flue gas absorbed by the circulating spray is discharged through the chimney after defogging.
The denitration method of flue gas of the sintering to oxidation as claimed in claim 1, wherein said plasma generator means ozone plasma radical production was 6-12kg / h, the flue gas containing the NO x 30,000 -50000Nm 3 /h.
The method of oxidizing sintering flue gas denitration according to claim 1, wherein the ozone plasma generator device comprises an ozone generator, wherein the ozone generator has an operating voltage of 5 kV and a power supply frequency of 800-1200 Hz.
The denitration method of flue gas of the sintering oxidation of claim 1, wherein said mixture of flue gas mixing in step 3) and the oxygen-containing source of NO x in the NO and O 3 mass ratio is 30: 1.
The denitration method of flue gas of the sintering oxidation of claim 1, wherein the flue gas containing NO 2 in the NO x mass ratio accounted for 1-4% of the flue gas, the flue gas NO accounting mass The ratio is 96-99%.
The oxidation sintering flue gas denitration method according to claim 6, characterized in that the NO x -containing flue gas mass ratio of NO 2 accounted for 2% of the flue gas, the flue gas NO accounting mass ratio 98%.
A denitration system for use in the method of any of claims 1-7, characterized in that the denitration system comprises a detection device, a flue gas intake device, an ozone plasma generator device, a controller, a denitration device, and a spray a device, a desulfurization tower device, an exhaust gas discharge device; the controller is connected to the detection device and the flue gas intake device, the ozone plasma generator device; the denitration device is connected to the ozone plasma generator device and the flue gas intake device, The desulfurization tower device is provided with a spraying device, and the denitration device is connected to the desulfurization tower device, and the exhaust gas discharge device is disposed at the top end of the desulfurization tower device.
The denitration system of claim 8 wherein said ozone plasma generator means comprises An ozone generator, a cooling water system; the ozone generator comprises a reactor body, a fan, an ozone uniform feeding device, and a discharge tube; the cooling water system is disposed on an outer wall of the discharge tube; and the ozone uniform feeding device Multi-point equalization is used.
The denitration system according to claim 9, wherein the cooling water system comprises a plate heat exchanger, a circulating water pump, an expansion tank, a base and a meter, and the plate heat exchanger and the expansion tank are integrally fixed on the base .
The denitration system according to claim 9, wherein the fan is a mixed flow axial flow fan having a power of 18.5 kW.
The denitration system according to claim 9, wherein the cooling water system is provided with a flow switch, a temperature transmitter, and an alarm system.