CN115945024A - Flue gas desulfurization and denitrification and adsorbent regeneration method and device, and flue gas combined desulfurization and denitrification method and device - Google Patents

Abstract

Flue gas desulfurization and denitrification and adsorbent regeneration method and device, flue gas combined desulfurization and denitrification method and device, flue gas desulfurization and denitrification and adsorbent regeneration method include: crude flue gas enters a fixed bed adsorber filled with adsorbent, and adsorbent contact, and adsorb and remove nitrogen oxides and/or sulfur oxides in the flue gas at a temperature of 30-140 ° C, and obtain purified flue gas at the outlet of the fixed-bed adsorber; when the flue gas at the outlet of the fixed-bed adsorber When the nitrogen oxides and/or sulfur oxides in the gas exceed the standard, switch the fixed bed adsorber to enter the regeneration mode, contact with reducing gas, mixed gas with or without inert gas, and react under the condition of adsorbent regeneration. After regeneration The fixed bed adsorber is switched to the adsorption reaction mode. The method provided by the invention adsorbs and removes NOx and _SO2 in flue gas under low temperature conditions, and has great flexibility in pressure adaptation. The method and device provided by the invention do not produce secondary pollution problems such as waste liquid and waste residue.

Description

Flue gas desulfurization and denitrification and adsorbent regeneration method and device, flue gas combined desulfurization and denitrification method and device

technical field

The invention relates to a method for removing pollutants in industrial flue gas, more specifically, relates to a method for removing nitrogen oxides and sulfur oxides in industrial flue gas, and belongs to the technical field of flue waste gas comprehensive treatment.

Background technique

With the rapid development of economy and society, my country's emission restrictions on sulfur oxides (SOx, referred to as sulfur) and nitrogen oxides (NOx, referred to as nitrate) in industrial waste gas are becoming more and more stringent. Through the introduction, absorption and innovation of technologies over the years, a variety of desulfurization and denitrification technical routes have been formed, such as wet methods (such as limestone-gypsum method, ammonia method, double subtraction method, seawater desulfurization and ozone, Hydrogen peroxide, sodium chlorite, potassium permanganate method oxidative denitrification, etc.), semi-dry method (such as rotary spray method, circulating fluidized bed, etc.) and dry method (such as electron beam irradiation method, activated coke desulfurization, etc.). Of course, various technical methods have the best reaction operating conditions in use, and the most sensitive one is the temperature of flue gas. When the flue gas temperature is higher than the reaction temperature, it needs to be cooled in advance. Otherwise, the flue gas temperature is lower than the reaction temperature value, and the temperature needs to be raised in advance. Negative Effects.

At present, the discharge temperature of most industrial flue gas is between 150 and 250°C. The wet desulfurization process, which accounts for about 85% of the market share, has an action temperature of 50-60°C, and the flue gas outlet temperature of some devices equipped with demisting and whitening facilities is 20-50°C; the action temperature of semi-dry desulfurization is between 85 ~ 95 ℃; the action temperature of activated coke desulfurization is 120 ~ 150 ℃, so in order to adapt to the function of desulfurization technology, it is usually necessary to cool down the flue gas. Although the traditional selective catalytic reduction denitrification technology has high efficiency and mature and reliable technology, the catalytic reaction window is sensitive, and the temperature is 320-450°C; while the medium-low temperature flue gas denitrification technology at 180-300°C has not yet reached the mature stage; as for The low-temperature flue gas denitrification technology below 180 °C is in the stage of exploration and development as a demand hotspot, so for the flue gas denitrification process, the temperature of the flue gas must be raised in most cases. Therefore, for the cooling and heating of the flue gas, it will not only affect the comprehensive utilization of flue gas energy, but also inevitably increase the operating cost of flue gas treatment.

In addition, the combination of traditional flue gas treatment is basically that the selective catalytic reduction denitrification unit comes first, followed by the desulfurization unit, so that during the denitrification stage, due to the interaction between ammonia, oxygen, sulfur oxides, etc., sulfuric acid will be generated Ammonium, ammonium bisulfate, sulfur trioxide and other by-products cause secondary pollution such as fouling, corrosion, and blue feather phenomenon to heat exchange equipment, reaction equipment, and chimneys downstream of the flue gas.

Although new technologies for simultaneous flue gas desulfurization and denitrification have emerged, such as CN101209391A and CN109663496A disclose simultaneous desulfurization and denitrification technologies for low temperature 150-300°C and high temperature 400-600°C, but in view of the fact that flue gas desulfurization devices already exist widely and Some devices have not been completed soon, and it will be expensive to tear them down in the short term. Therefore, implementing low-temperature denitrification for the existing desulfurized flue gas is an expedient measure, but it is also a top priority.

CN109621707A discloses a circulating fluidized bed device for low-temperature denitrification of industrial flue gas, which still follows the principle of selective catalytic denitrification, and the denitrification catalyst is a modified powdery V ₂ O ₅ -TiO ₂ catalyst, and the flue gas treatment temperature is From 135°C to 180°C, the reducing agent is still ammonia. When the temperature is lower than 135 °C, preheating treatment is required, which also exposes the problem of the applicable lower limit of the selective catalytic denitrification process in the low temperature region.

Contents of the invention

One of the technical problems to be solved by the present invention is to provide a method and device for flue gas dry adsorption desulfurization and denitrification at temperatures below 150°C or even lower.

The second technical problem to be solved by the present invention is to provide a method and device for flue gas combined desulfurization and denitrification.

A method for flue gas desulfurization and denitrification and adsorbent regeneration. The crude flue gas enters a fixed-bed adsorber filled with adsorbent, contacts with the adsorbent, and absorbs and removes nitrogen oxides in the flue gas at a temperature of 30-140°C. and/or sulfur oxides, the purified flue gas is obtained at the outlet of the fixed bed adsorber; when the nitrogen oxides and/or sulfur oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, switch the fixed bed adsorber to enter regeneration Mode, contact with reducing gas, mixed gas with or without inert gas to react under regeneration conditions, and the regenerated fixed bed adsorber switches to adsorption reaction mode.

A device for flue gas desulfurization and denitrification and adsorbent regeneration, comprising sequentially connected flue gas switching devices, at least two fixed-bed adsorbers arranged in parallel, induced draft fans, and flue gas composition monitors; wherein, the flue gas pipeline is connected to the The inlet of the flue gas switching device is connected, the outlet of the flue gas switching device is connected to the inlet of the fixed bed adsorber, the outlet of the fixed bed adsorber is connected to the inlet of the induced draft fan, and the flue gas pipeline at the exit of the induced draft fan is provided with a sampling port for a flue gas composition detector; A temperature control system is installed outside the fixed bed adsorber.

A flue gas combined desulfurization and denitrification method, comprising:

(1) The crude flue gas containing sulfur oxides and nitrogen oxides is subjected to flue gas desulfurization to obtain desulfurized crude flue gas, and the flue gas desulfurization is selected from one of wet desulfurization, semi-dry desulfurization, and dry desulfurization methods kind;

(2) The desulfurized crude flue gas from step (1) is directly introduced into the fixed bed adsorber, contacts with the adsorbent, and absorbs and removes nitrogen oxides in the flue gas at a temperature of 30-140°C. The purified flue gas is obtained at the outlet of the bed adsorber; when the nitrogen oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, the fixed bed adsorber is switched to the regeneration mode, and the mixed gas of the reducing gas and the inert gas is in contact with the regeneration mode. The reaction is carried out under the conditions, and the regenerated fixed-bed adsorber is switched to the adsorption reaction mode.

A flue gas combined desulfurization and denitrification reaction device, comprising:

(1) Flue gas desulfurization unit;

(2) The flue gas desulfurization and denitrification and adsorbent regeneration device communicated with the flue gas outlet of the flue gas desulfurization unit.

The beneficial effects of the flue gas desulfurization and denitrification and adsorbent regeneration method and device provided by the present invention are:

The invention adopts a fixed bed adsorber to adsorb and remove NOx in flue gas under low temperature conditions, or simultaneously adsorb and remove NOx and SO ₂ in flue gas, the adsorption temperature is low, and the pressure adaptability is large. Moreover, when working, the method of one use and one standby is adopted. When the fixed bed adsorber is saturated, it is switched to other fixed bed adsorbers through the flue gas switching device, and the saturated fixed bed adsorber is regenerated at the same time, realizing the flue gas Continuous operation of gas adsorption desulfurization and denitrification. The method and device provided by the invention do not produce secondary pollution problems such as waste liquid and waste residue.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention.

Fig. 1 is a schematic flow chart of the method for gas desulfurization and denitrification and adsorbent regeneration provided by the present invention.

Explanation of reference signs:

1. Flue gas inlet; 2. Reducing gas inlet; 3. Inert gas inlet; 4. Purified flue gas outlet; 5. Reducing tail gas outlet; 11, 12. Flue gas switching device; 13. Fixed bed adsorber; 14. Heating and heat preservation system; 15. Induced fan; 16. 18. Flue gas composition detector; 17. Regeneration tail gas switching device; 21. Reducing gas control valve; 22. Inert gas control valve; 23. Flue gas outlet control valve; 24 , Reduction exhaust gas outlet control valve.

Detailed ways

Specific embodiments disclosed in the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure. The pressure mentioned in the text refers to the gauge pressure.

Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the common understanding in the art, the definition herein shall prevail.

In the first aspect, the present invention provides a method for flue gas desulfurization and denitrification and adsorbent regeneration. The crude flue gas enters the fixed bed adsorber filled with adsorbent, contacts with the adsorbent, and adsorbs and removes the adsorbent at a temperature of 30-140°C. The nitrogen oxides and/or sulfur oxides in the flue gas are purified at the outlet of the fixed bed adsorber; when the nitrogen oxides and/or sulfur oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, switch The fixed bed adsorber enters the regeneration mode, contacts with the reducing gas, the mixed gas containing or not containing the inert gas and reacts under the regeneration condition, and the regenerated fixed bed adsorber switches to the adsorption reaction mode.

Preferably, at least two fixed-bed adsorbers are arranged in parallel, and at least one fixed-bed adsorber is in the adsorption reaction mode.

In the method provided by the present invention, the temperature of the crude flue gas introduced into the denitrification reactor is 45-135°C; the pressure of the adsorption reaction is -5.0-100kPa, and the volume space velocity is 500-12000h ^-1 ; the regeneration conditions The temperature is 120-600°C, the pressure is -5.0-100kPa, and the volumetric space velocity is 2-1000h ^-1 ;

Preferably, the adsorption reaction conditions are as follows: the temperature is 50-110°C, the pressure is -4.0-8.0kPa, and the volume space velocity is 1000-10000h ^-1 .

In the method provided by the invention, the crude flue gas contains carbon dioxide, water vapor, oxygen and nitrogen oxides, with or without sulfur oxides; preferably, the content of the sulfur oxides is 35-5000mg/ m ³ , the nitrogen oxide content is 50-2000 mg/m ³ .

Preferably, the water vapor content in the crude flue gas is lower than the saturated water vapor content under the flue gas temperature and pressure conditions, so as to ensure that there is no liquid water in the flue gas.

In the method provided by the present invention, when the water vapor content in the crude flue gas is higher than the upper limit of saturated water vapor under flue gas temperature and pressure conditions and liquid water exists, the flue gas needs to be dehydrated. For example, one or more solid adsorbents of activated alumina, silica gel and molecular sieves are used for dehydration treatment.

When the crude flue gas contains only nitrogen oxides, the adsorbent only adsorbs nitrogen oxides. Preferably, the regeneration conditions of the adsorbent are as follows: temperature is 195-220°C, pressure is -4.0-7.0kPa, and volumetric The speed is 5-500h ^-1 .

When the crude flue gas contains nitrogen oxides and sulfur oxides at the same time, the adsorbent adsorbs nitrogen oxides and sulfur oxides at the same time. Preferably, the regeneration conditions of the adsorbent are: the temperature is 400-600 ° C, the pressure It is -5.0~100kPa, and the volumetric space velocity is 2~1000h ^-1 . More preferably, the regeneration conditions are that the temperature is 460-545°C, the pressure is -4.0-7.0kPa, and the volume space velocity is 5-500h ^-1 .

In the method provided by the present invention, the reducing gas is selected from one or more of hydrogen, ammonia, methanol, carbon monoxide, alkanes containing 1-5 carbon atoms and alkenes containing 1-5 carbon atoms. The mixture of species; the inert gas is nitrogen and/or water vapor.

In the method provided by the present invention, the adsorbent is selected from one or at least two of catalytic cracking catalysts, sodium oxide, magnesium oxide, aluminum oxide, titanium oxide, vanadium oxide, iron oxide, calcium oxide, copper oxide and zinc oxide The combination;

Preferably, the adsorbent is selected from one or a combination of at least two of catalytic cracking catalysts, magnesium oxide, aluminum oxide, titanium oxide and calcium oxide.

When the adsorbent is a catalytic cracking catalyst, it includes a carrier and an active metal component loaded on the carrier. The carrier is a porous inorganic substance, preferably one or more of heat-resistant inorganic oxides and molecular sieves. Specific examples of the heat-resistant inorganic oxide may include, but are not limited to, one or more of alumina, silica, magnesia, and zirconia. The molecular sieve can be one or more of microporous silicon aluminum molecular sieve, microporous aluminum phosphorus molecular sieve and mesoporous silicon aluminum molecular sieve. , L-type molecular sieves, Beta-type molecular sieves, and ZSM-type molecular sieves, or one or more of them.

The active metal component can be a conventional choice. Preferably, the active metal component is selected from Group IA metals, Group IIIA non-aluminum metals, Group IVA metals, Group VA metals, Group IB metals, Group IIB metals, and Group VB metals in the periodic table of elements. One or more of Group VIB metals, Group VIIB metals and Group VIII non-noble metals. Specifically, the active metal component is one or more of rare earth elements, sodium, potassium, antimony, copper, zinc, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel.

In the method provided by the present invention, the flue gas to be treated enters the inlet at the bottom of the fixed-bed adsorber through the flue gas switching device, and the fixed-bed adsorber is filled with adsorbent, and the sulfur oxidation in the flue gas is removed by adsorption after contacting with the flue gas substances and nitrogen oxides. When the flue gas composition monitor detects that the sulfur oxides and nitrogen oxides in the flue gas outlet exceed the standard, the flue gas is input into any other fixed-bed adsorber through the flue gas switching device, and the saturated fixed-bed adsorber is Regeneration, the regenerated adsorbent can continue to be used.

In the second aspect, the present invention provides a flue gas denitrification and adsorbent regeneration device, which includes a flue gas switching device connected in sequence, at least two fixed bed adsorbers arranged in parallel, an induced draft fan, and a flue gas composition monitor; wherein, the flue gas The gas pipeline is connected to the inlet of the flue gas switching device, the outlet of the flue gas switching device is connected to the inlet of the fixed bed adsorber, the outlet of the fixed bed adsorber is connected to the inlet of the induced draft fan, and the flue gas composition detection device is installed on the flue gas pipeline at the outlet of the induced draft fan The sampling port of the device; the fixed bed adsorber is provided with a temperature control system outside.

Wherein, the flue gas switching device includes a flue gas inlet control valve connected to the inlet of each fixed bed adsorber, a reducing gas and an inert gas inlet control valve connected to the outlet of each fixed bed adsorber The flue gas outlet control valve, the reduction tail gas control valve, and the corresponding connecting pipelines.

A second gas inlet is provided at the bottom of the fixed bed adsorber as a reducing gas and/or inert gas inlet. Control valves are installed on the reducing gas and inert gas pipelines. The fixed bed adsorber is provided with two outlets, a flue gas outlet and a regenerated tail gas outlet, each of which is connected to a flue gas composition detector, and control valves are arranged on the pipelines.

When the flue gas desulfurization and denitrification reaction is carried out in the fixed bed adsorber, the flue gas outlet control valve is in an open state; the reducing gas and inert gas control valves and the reducing tail gas control valve are all in a closed state.

When the adsorbent regeneration reaction is carried out in the fixed bed adsorber, the reducing gas and inert gas control valves and the reducing tail gas control valve are all in an open state; the flue gas outlet control valve is in a closed state.

In the third aspect, the present invention provides a flue gas combined desulfurization and denitrification method, comprising:

(1) The crude flue gas containing sulfur oxides and nitrogen oxides is subjected to flue gas desulfurization to obtain desulfurized crude flue gas, and the flue gas desulfurization is selected from one of wet desulfurization, semi-dry desulfurization, and dry desulfurization methods kind;

(2) The desulfurized crude flue gas from step (1) is directly introduced into the fixed bed adsorber, contacts with the adsorbent, and absorbs and removes nitrogen oxides in the flue gas at a temperature of 30-140°C. The purified flue gas is obtained at the outlet of the bed adsorber; when the nitrogen oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, switch the fixed bed adsorber to enter the regeneration mode, and mix with reducing gas, with or without inert gas The gas contact reacts under regeneration conditions, and the regenerated fixed bed adsorber switches to the adsorption reaction mode.

In the fourth aspect, the present invention provides a flue gas combined desulfurization and denitrification reaction device, including:

(1) Flue gas desulfurization unit;

(2) The flue gas desulfurization and denitrification and adsorbent regeneration device communicated with the flue gas outlet of the flue gas desulfurization unit. Wherein, the desulfurization unit is a wet desulfurization unit, a semi-dry desulfurization unit or a dry desulfurization unit.

The specific implementation of the method provided by the present invention will be described in detail below with reference to accompanying drawing 1, but the present invention is not limited thereto.

As shown in Figure 1, the flue gas to be treated enters the flue gas switching valve 11 from the flue gas inlet 1. At this time, the reducing gas control valve 21, the inert gas control valve 22 and the reducing tail gas outlet control valve 24 are closed, and the flue gas outlet is opened. The control valve 23 cooperates with the switching device 12 to connect the outlet of the purified exhaust gas with the inlet of the induced draft fan 15, and the induced draft fan 15 draws the flue gas into the bottom inlet of the fixed bed adsorber 13 through the flue gas switching device 12, and the fixed bed adsorber 13 is filled with adsorption After being in contact with the flue gas, the sulfur oxides and nitrogen oxides in the flue gas are removed by adsorption.

The purified flue gas enters the exhaust pipe through the flue gas outlet 4, the flue gas switching device 12, and the induced draft fan 15, and part of it enters the flue gas composition monitor 16 through the analysis sampling port. When nitrogen oxides and/or sulfur oxides are detected When the limit is exceeded, the flue gas is input to any other fixed-bed adsorber through the flue gas switching device 11 . Then, close the flue gas outlet control valve 23, the fixed bed adsorber is heated up, open the inert gas control valve 22 and the reduction tail gas outlet control valve 24 at the same time, pass the inert gas into the fixed bed adsorber 13, when the flue gas composition is detected After the detector 18 monitors that the oxygen concentration is zero, the reducing gas control valve 21 is opened to pass the reducing gas into the fixed bed adsorber 13 . When the flue gas composition detector 18 detects that the concentration of hydrogen sulfide is zero, the regeneration of the adsorbent is completed, the reducing gas control valve 21 is closed, the fixed bed adsorber 13 is cooled with inert gas, and the flue gas switching device 11 is waiting for switching.

It should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner if there is no contradiction. The method will not be further explained.

The method provided by the present invention is further illustrated below by way of examples, but the present invention is not thereby limited in any way.

In embodiment and comparative example:

ZSM5 molecular sieve is produced by Qilu Catalyst Factory of Sinopec Catalyst Branch Company, with a silicon-aluminum ratio of 100; pseudo-boehmite is produced by Shandong Aluminum Company, with an alumina content of 61%.

Hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O), cerium nitrate (Ce(NO) ₃ 6H ₂ O), titanium oxide (TiO ₂ ), calcium hydroxide (Ca(OH) ₂ ) , iron nitrate (Fe(NO) ₃ ·9H ₂ O), activated alumina, and 13X molecular sieve (diameter 3-4mm spherical shape) are commercially available.

Adsorbent preparation example 1

(1) Stir 25.9g of ZSM5 molecular sieve fine powder, 49.0g of pseudoboehmite, and an appropriate amount of deionized water at room temperature to obtain a colloid and age it for 4 hours, then dry it in the shade at room temperature and extrude it into bars with a cross-sectional diameter of 1mm. After being dried at 120°C for 2 hours, it was broken into a cylinder with a length of about 3 mm, and then roasted in a muffle furnace at 500°C for 4 hours to obtain a carrier.

(2) Prepare 3wt% cerium nitrate solution, take 60ml of cerium nitrate solution and impregnate the carrier prepared in step (1) at room temperature for 8h, then dry at 120°C for 2h, then transfer to muffle furnace and bake at 500°C for 8h, cool Finally, 56.8 g of adsorbent A was obtained, and its chemical weight ratio composition was: SiO ₂ : Al ₂ O ₃ : Ce ₂ O ₃ =45.21:53.13:1.61.

Adsorbent preparation example 2

(1) Hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O) 5.0g, titanium oxide 1.0g, calcium hydroxide 8.0g, pseudo-boehmite 112.0g, appropriate amount of deionized water at room temperature Stir evenly at high temperature to obtain colloid and age for 4 hours, dry in the shade at room temperature and extrude into strips with a cross-sectional diameter of 1mm, dry at 120°C for 2 hours, and then break into cylinders with a length of about 3mm The carrier was obtained by calcining in a Mafu furnace for 4 hours.

(2) Prepare 2% ferric nitrate solution, take 83ml of ferric nitrate solution and impregnate the pre-prepared carrier at room temperature for 8h, then dry at 120°C for 2h, then transfer to a muffle furnace and roast at 500°C for 8h, after cooling, get Adsorbent B totaled 78.6g. Its chemical weight ratio composition is: MgO: Al ₂ O ₃ : TiO ₂ : Fe ₂ O ₃ : CaO=2.58:88.00:1.21:0.70:7.36.

The analysis method of the composition of the crude flue gas and flue gas after adsorption (adsorption tail gas) in the comparative examples and examples adopts the MGS900 type quasi-situ continuous on-line analysis system (integrated by Beijing Jiexiite Technology Development Co., Ltd.) to measure. The core of the system is the Multigas2030FT-IR analyzer produced by MKS in the United States, equipped with a Novatech 1231 ZrO oxygen analyzer, which records data every 10s. The host Multigas2030 FT-IR is a gas measuring instrument based on the principle of quasi-in-situ FT-IR. The sample cell and detector work at 191°C and can measure more than 380 gaseous substances.

The analysis method for the composition of the adsorbent regeneration tail gas in the comparative examples and examples adopts an Agilent 3000 gas chromatograph (provided by Agilent Technologies Co., Ltd.) for online analysis.

Example 1

A device similar to that shown in Figure 1 is used, but only one adsorber is used, and the mode of alternating adsorption-regeneration-readsorption is adopted, and nitrogen is purged before the adsorption and regeneration modes are alternated. The flue gas composition is shown in Table 1. The adsorbent A is loaded into the fixed bed adsorber, and the loading amount of the adsorbent is 10 g. The adsorption operation temperature is 140°C, the pressure is 6kPa, and the volume space velocity is 10000h ^-1 ; the regeneration operation temperature is 220°C, the pressure is 6kPa, and the volume space velocity is 500h ^-1 . The reducing gas is nitrogen and ammonia (the amount of ammonia is 120% of the theoretical molar amount for reducing the nitrogen oxides in the flue gas feed to simple substances), and the inert gas is nitrogen. The adsorbent in the fixed bed undergoes adsorption operation again after a regeneration, and the single adsorption operation time is about 30 minutes. The results of the second adsorption experiment are shown in Table 5.

Table 1 Composition of flue gas

Example 2

Adsorbent B was used as the adsorbent. The adsorption and regeneration pressures are both 50kPa, and the flue gas composition, device and method are the same as in Example 1. The experimental results are shown in Table 5.

Example 3

Adsorbent A was used as the adsorbent, and the flue gas composition is shown in Table 2. The adsorption pressure and regeneration pressure were both -3kPa, the adsorption temperature was 90°C, and other operating conditions were the same as in Example 1. The experimental results are shown in Table 6.

Table 2 Composition of flue gas

Example 4

Adsorbent B was used as the adsorbent. The adsorption and regeneration pressures are both 100kPa, and the flue gas composition, device and method are the same as in Example 3. The experimental results are shown in Table 6.

Example 5

Adsorbent A was used as the adsorbent, and the flue gas composition is shown in Table 3. The adsorption and regeneration pressures are both 60kPa, the adsorption operating temperature is 110°C, the regeneration operating temperature is 545°C, and the reducing gas is nitrogen and hydrogen (hydrogen gas fraction is 10%). Other operating conditions are the same as in Example 1, and the experimental results are shown in the table 6.

Table 3 Composition of flue gas

Example 6

Adsorbent B was used as the adsorbent. The flue gas adsorption temperature is 135° C. Others such as flue gas composition, device and regeneration method are the same as in Example 5. The experimental results are shown in Table 6.

Comparative example 1

Comparative Example 1 illustrates the effect of using conventional flue gas adsorption and denitrification conditions for flue gas heating after conventional desulfurization treatment (reaction temperature 60° C.).

The adsorption reaction device, adsorption reaction, adsorbent regeneration method, and flue gas composition are the same as in Example 1, except that the adsorbent is Adsorbent B, and the conventional flue gas adsorption and denitrification reaction conditions are adopted. The flue gas adsorption temperature is 250 ° C. The adsorbent in the bed undergoes adsorption operation again after a regeneration, and the single adsorption operation time is about 30 minutes. The results of the second adsorption experiment are shown in Table 5.

Example 7

The experimental device and method are the same as in Example 1, except that Adsorbent A is used as the adsorbent, and the flue gas in Example 1 is passed through a dehydrating agent, which is activated alumina. The flue gas composition is shown in Table 4. The adsorption pressure and regeneration pressure were both -1kPa, the adsorption temperature was 40°C, and other operating conditions were the same as in Example 1. The experimental results are shown in Table 5. The flue gas is dehydrated to control the occurrence of liquid water in the flue gas.

Table 4 Composition of flue gas

Example 8

Experimental apparatus and method, operating conditions are the same as embodiment 7, and adsorbent adopts adsorbent B. The flue gas of Example 1 passed through the dehydrating agent 13X molecular sieve, and the composition of the flue gas is shown in Table 4. The experimental results are shown in Table 5.

table 5

Example 1 Example 2 Example 7 Example 8 Comparative example 1 Adsorbent A B A B B Adsorption temperature, ℃ 140 140 40 40 250 Adsorption pressure (table), kPa 6 50 -1 -1 6 regeneration temperature, ℃ 220 220 220 220 220 Regeneration pressure (gauge), kPa 6 50 -1 -1 6 Crude flue gas SO2 concentration, mg/m3 0 0 0 0 0 NO concentration in crude flue gas, mg/m3 275 275 285 285 275 NO concentration in adsorption tail gas, mg/m3 9.6 7.8 7.3 5.2 126.7 NO removal rate, % 96.51 97.16 97.44 98.18 53.93

*Note: 1. The NO concentration in the crude flue gas is taken as the arithmetic mean value of the detection fluctuation interval.

2. No NO ₂ was detected in the adsorption tail gas, and the removal rate of NO ₂ was 100%.

Table 6

Example 3 Example 4 Example 5 Example 6 Adsorbent A B A B Adsorption temperature, ℃ 90 90 110 135 Adsorption pressure (table), kPa -3 100 60 60 regeneration temperature, ℃ 220 220 545 545 Regeneration pressure (gauge), kPa -3 100 60 60 <![CDATA[Crude flue gas SO₂ concentration, mg/m³]]> 22.5 22.5 2800 2800 <![CDATA[SO₂ concentration in adsorption tail gas, mg/m³]]> 1.0 0.5 26.8 15.3 <![CDATA[SO₂removal rate, %]]> 95.56 97.78 99.04 99.45 <![CDATA[NO concentration in crude flue gas, mg/m³]]> 275 275 275 275 <![CDATA[NO concentration in adsorption tail gas, mg/m³]]> 12.5 10.3 14.3 11.6 NO removal rate, % 95.45 96.25 94.80 95.78

*Note: 1. The reference concentration of SO ₂ , NO and NO ₂ in the crude flue gas is the arithmetic mean value of the fluctuation interval;

2. No NO ₂ was detected in the adsorption tail gas, and the removal rate of NO ₂ was 100%.

It can be seen from Table 5 and Table 6 that the use of two different adsorbents to treat low-temperature flue gas shows a high removal rate of sulfur oxides and nitrogen oxides, and the adsorbents have been effectively regenerated. Comparative Example 1 shows that low-temperature desulfurization is used in the pre-sequence and then temperature-raising denitrification is used, and the effect is not good. Examples 7 and 8 are the experimental results of the flue gas being treated with dehydration at low temperature and without the presence of liquid droplets, indicating that the flue gas with supersaturated water in a certain state can be effectively removed after dehydration treatment. Water-insoluble pollutants (NO). In a word, the flue gas denitrification and adsorbent regeneration method and device provided by the present invention are practical and can effectively remove nitrogen oxides and/or sulfur oxides in flue gas.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

Claims (13)

1. A method for flue gas desulfurization and denitrification and adsorbent regeneration, characterized in that the crude flue gas enters a fixed-bed adsorber filled with adsorbent, contacts with the adsorbent, and is adsorbed and removed at a temperature of 30 to 140°C The nitrogen oxides and/or sulfur oxides in the flue gas are purified at the outlet of the fixed bed adsorber; when the nitrogen oxides and/or sulfur oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, switch The fixed-bed adsorber enters the regeneration mode, contacts with reducing gas, mixed gas with or without inert gas, and reacts under the condition of adsorbent regeneration, and the regenerated fixed-bed adsorber switches to the adsorption reaction mode; Preferably, at least two fixed-bed adsorbers are arranged in parallel, and at least one fixed-bed adsorber is in the adsorption reaction mode. 2. The flue gas desulfurization and denitrification and adsorbent regeneration method according to claim 1, characterized in that, the temperature of the crude flue gas introduced into the denitrification reactor is 45 to 135°C; the pressure of the adsorption reaction is -5.0 to 100kPa, the volume space velocity is 500-12000h ^-1 ; the adsorbent regeneration conditions are temperature 120-600°C, pressure -5.0-100kPa, volume space velocity 2-1000h ^-1 ; Preferably, the adsorption reaction conditions are as follows: the temperature is 50-110°C, the pressure is -4.0-8.0kPa, and the volume space velocity is 1000-10000h ^-1 . 3. according to claim 1 or 2 described flue gas desulfurization and denitrification and adsorbent regeneration method, it is characterized in that, described adsorbent is catalytic cracking catalyst, sodium oxide, magnesium oxide, aluminum oxide, titanium oxide, vanadium oxide, oxide One or a combination of at least two of iron, calcium oxide, copper oxide and zinc oxide; It is preferably one or a combination of at least two of catalytic cracking catalyst, magnesium oxide, aluminum oxide, titanium oxide and calcium oxide. 4. according to claim 1 or 2 described flue gas desulfurization and denitrification and adsorbent regeneration method, it is characterized in that, described reducing gas is selected from hydrogen, ammonia, methanol, carbon monoxide, containing 1-5 carbon atom A mixture of one or more of alkanes and alkenes with 1-5 carbon atoms; the inert gas is nitrogen and/or water vapor. 5. According to the flue gas desulfurization and denitrification and adsorbent regeneration method described in claim 1 or 2, it is characterized in that, carbon dioxide, water vapor, oxygen and nitrogen oxides are contained in the described crude flue gas; Preferably, the water vapor content in the crude flue gas is lower than the saturated water vapor content under the flue gas temperature and pressure conditions; Preferably, the nitrogen oxide content is 50-2000 mg/m ³ . 6. The flue gas desulfurization and denitrification method and adsorbent regeneration method according to claim 5, characterized in that the regeneration conditions are that the temperature is 195-220°C, the pressure is -4.0-7.0kPa, and the volumetric space velocity is 5-500h ^-1 . 7. The flue gas desulfurization and denitrification and adsorbent regeneration method according to claim 1 or 2, wherein the crude flue gas contains carbon dioxide, water vapor, oxygen, sulfur oxides and nitrogen oxides; Preferably, the content of the sulfur oxide is 35-5000 mg/m ³ , and the content of the nitrogen oxide is 50-2000 mg/m ³ . 8. The flue gas desulfurization and denitrification method and adsorbent regeneration method according to claim 7, wherein the regeneration conditions are as follows: temperature is 400-600°C, pressure is -5.0-100kPa, and volumetric space velocity is 2-1000h ^-1 . 9. A device for flue gas desulfurization and denitrification and adsorbent regeneration, characterized in that it includes sequentially connected flue gas switching devices, at least two fixed-bed adsorbers arranged in parallel, induced draft fans and flue gas composition monitors; wherein, the flue gas The gas pipeline is connected to the inlet of the flue gas switching device, the outlet of the flue gas switching device is connected to the inlet of the fixed bed adsorber, the outlet of the fixed bed adsorber is connected to the inlet of the induced draft fan, and the flue gas composition detection device is installed on the flue gas pipeline at the outlet of the induced draft fan The sampling port of the device; the fixed bed adsorber is provided with a temperature control system outside. 10. The flue gas denitrification and adsorbent regeneration device according to claim 9, wherein said flue gas switching device comprises a flue gas inlet control valve connected to the inlet of each said fixed bed adsorber, Reducing gas and inert gas inlet control valves, flue gas outlet control valves connected to the outlet of each fixed-bed adsorber, reduction tail gas control valves, and corresponding connecting pipelines. 11. A flue gas combined desulfurization and denitrification method, characterized in that it comprises: (1) The crude flue gas containing sulfur oxides and nitrogen oxides is subjected to flue gas desulfurization to obtain desulfurized crude flue gas, and the flue gas desulfurization is selected from one of wet desulfurization, semi-dry desulfurization, and dry desulfurization methods kind; (2) The desulfurized crude flue gas from step (1) is directly introduced into the fixed bed adsorber, contacts with the adsorbent, and absorbs and removes nitrogen oxides in the flue gas at a temperature of 30-140°C. The purified flue gas is obtained at the outlet of the bed adsorber; when the nitrogen oxides in the flue gas at the outlet of the fixed bed adsorber exceed the standard, the fixed bed adsorber is switched to the regeneration mode, and the mixed gas of the reducing gas and the inert gas is in contact with the regeneration mode. The reaction is carried out under the conditions, and the regenerated fixed-bed adsorber is switched to the adsorption reaction mode. 12. A flue gas combined desulfurization and denitrification reaction device, characterized in that the device includes: (1) Flue gas desulfurization unit; (2) The flue gas desulfurization, denitrification and adsorbent regeneration device according to claim 9 or 10, which is connected to the flue gas outlet of the flue gas desulfurization unit. 13. The flue gas desulfurization and denitrification reaction device according to claim 12, wherein the desulfurization unit is a wet desulfurization unit, a semi-dry desulfurization unit or a dry desulfurization unit.

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