Water-phase non-ammonia denitration agent for waste incineration flue gas and application thereof

Abstract

The invention provides a water-phase non-ammonia denitrifying agent for waste incineration flue gas and application of the water-phase non-ammonia denitrifying agent, and belongs to the technical field of flue gas denitrification. The water-phase non-ammonia denitration agent for the waste incineration flue gas comprises the following components in parts by weight: 40-80 parts of a liquid carbon source; 5-15 parts of an alcohol compound; and 5-10 parts of an additive. According to the water-phase non-ammonia denitrifying agent for the waste incineration flue gas, cheap raw materials are selected as reducing agents, meanwhile, leachate in a waste plant and the like can be utilized, specific components and proportions are adopted, the water-phase non-ammonia denitrifying agent can be directly applied to an SNCR system, the denitrifying efficiency is improved, the denitrifying efficiency reaches 80% or above, the content of NOx in the denitrified flue gas is as low as 80 mg / m < 3 > or below, and the water-phase non-ammonia denitrifying agent is suitable for industrial production. The method is superior to national emission standard requirements. Meanwhile, by adopting the denitration agent, the problem of high ammonia escape in an SNCR (selective non-catalytic reduction) system can be effectively solved. The denitration catalyst is prepared from cheap raw materials, the cost is low, the preparation method is simple, original SNCR process equipment can be utilized during use, and the denitration cost is further reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas denitrification, and in particular relates to a water-phase non-ammonia denitrification agent for waste incineration flue gas and an application thereof. Background Art

[0002] Waste incineration power generation is the first choice for domestic waste treatment, with its characteristics of volume reduction, resource utilization and harmlessness. As the market scale of waste incineration power generation industry grows, flue gas treatment becomes particularly important.

[0003] At present, the more mature flue gas denitrification technologies mainly include SNCR (selective non-catalytic reduction denitrification), SCR (selective catalytic reduction denitrification) and SNCR / SCR technology combined. Among them, SNCR is a selective non-catalytic reduction denitrification technology, that is, ammonia, urea or other reducing agents are injected into the furnace temperature area of ​​850℃~1100℃, and the reducing agent is rapidly thermally decomposed into NH3 and reacts with NOx in the flue gas to reduce it to N2 and H2O. SCR is a catalyst, and the NH3 of the reducing agent selectively reduces NOx to N2 at 200℃~400℃, and the oxidation reaction of NH3 and O2 almost does not occur, thereby reducing the consumption of NH3. The SNCR / SCR combined process is the combined application of SNCR technology and SCR technology, that is, in the high-temperature area at the top of the furnace, urea or ammonia water is used as a reducing agent, and the reducing agent is accurately distributed to each spray gun through a metering distribution and delivery device, and then sprayed into the furnace through the spray gun to achieve NOx removal. Excess ammonia escaping enters the SCR denitrification reactor equipped with a catalyst behind the furnace with the flue gas to achieve secondary denitrification.

[0004] The traditional SNCR is to spray a reducing agent aqueous solution into the furnace to reduce NOx in the flue gas to N2. Compared with SCR, its investment and operating costs are relatively low, but the denitrification efficiency of this technology is low. As the country's requirements for NOx emissions continue to increase, it is difficult for traditional SNCR to meet environmental protection standards. Some companies increase the denitrification efficiency by increasing the ammonia nitrogen ratio. The increase in the ammonia nitrogen ratio not only leads to increased operating costs, but also increases the amount of ammonia escape, which not only brings environmental pollution, but also easily causes corrosion of the flue gas duct. Adding more efficient denitrification technologies such as SCR on the basis of SNCR technology will inevitably increase costs, and considering factors such as the need to occupy land for the addition of new equipment, it is also difficult to achieve simply.

[0005] In view of the problems presented by SNCR, improving and upgrading SNCR technology is a research hotspot in this field. The Chinese invention patent with application number 201310158055.0 discloses an additive for flue gas SNCR denitrification and its application. In the temperature range of 760℃~850℃, a mixture of ammonia water or urea solution mixed with a small amount of cellulose ether and sodium salt is sprayed for denitrification. It can adapt to different oxygen concentration changes, reduce the generation of by-products, and make the denitrification efficiency reach 40~70%. Its denitrification efficiency is low and needs to be further improved.

[0006] The Chinese invention patent with application number 201310749404.6 discloses a denitration synergist and a SNCR denitration synergist method, wherein soluble metal compounds such as ammonium metavanadate, ammonium molybdate and copper hydroxide are added to the SNCR reductant as denitration synergists, which are mixed with ammonia water and then sprayed into the furnace, thereby widening the temperature window, allowing the denitration reaction to occur in each interval, and improving the overall denitration efficiency. However, the synergist uses metal oxides or metal salts such as vanadium, molybdenum, and tungsten, which are relatively expensive.

[0007] The Chinese invention patent with application number 202211563150.4 discloses a waste incineration flue gas water-phase loaded catalytic denitrifier and its application. The waste incineration flue gas water-phase loaded catalytic denitrifier adopts specific components and ratios, and is evenly sprayed into the waste incinerator. The sprayed manganese acetate and CaO powder are mixed with the flue gas, adsorbed and loaded on the fly ash in the waste incineration flue gas, and the fly ash is used as a carrier to complete the catalyst preparation process such as drying, roasting, and activation of the doped Ca-Mn two-component denitrification catalyst in the furnace. At the same time, the reducing agent in the denitrifier and the NOx generated by incineration are reduced to N2 under the action of the catalyst. The process can use the fly ash of waste incineration to carry out catalytic reduction reaction in the first, second, and third flues of the entire waste incinerator, as well as the horizontal flue and the flue of the waste heat boiler, which can overcome the defects of low denitrification efficiency and high ammonia escape of the existing SNCR system. However, the denitrifier is a solid-liquid mixture, which may block the equipment and increase the cost of manganese element treatment. Summary of the invention

[0008] In view of the above defects, the present invention provides a waste incineration flue gas water phase non-ammonia denitrification agent, which is applied to the SNCR denitrification system, thereby improving the denitrification effect, reducing ammonia escape, and reducing raw material costs.

[0009] The technical solution of the present invention is as follows:

[0010] The waste incineration flue gas water phase non-ammonia denitrification agent of the present invention comprises the following components in parts by weight:

[0011] 40-80 parts of liquid carbon source;

[0012] 5-15 parts of alcohol compound;

[0013] 5 to 10 parts of additives.

[0014] In one embodiment of the present invention, the liquid carbon source is a small molecule short-chain hydrocarbon.

[0015] In one embodiment of the present invention, the small molecule short chain hydrocarbons are derived from at least one of the leachate after anaerobic treatment of landfill, biogas slurry after anaerobic treatment of food waste, filtrate of domestic waste, and C5-C18 hydrocarbons.

[0016] In one embodiment of the present invention, the alcohol compound is a C1-C8 monohydric alcohol or a polyhydric alcohol.

[0017] In one embodiment of the present invention, the C1-C8 monohydric alcohol or polyhydric alcohol is at least one of methanol, ethanol, isopropanol, n-butanol, ethylene glycol, and glycerol.

[0018] In one embodiment of the present invention, the additive is at least one of sodium carboxymethyl cellulose, Tween-80, unsaturated branched alcohol and branched alcohol polyoxyethylene ether.

[0019] In one embodiment of the present invention, the unsaturated branched alcohol is 2,4,7,9-tetramethyl-5-decyne-4,7-diol; and the branched alcohol polyoxyethylene ether is isomeric decanol polyoxyethylene ether.

[0020] In one embodiment of the present invention, the following components are further included in parts by weight: 20 to 60 parts of water.

[0021] The invention also provides the use of a water-phase non-ammonia denitrifier for waste incineration flue gas in SNCR.

[0022] In one embodiment of the present invention, the application comprises the following steps:

[0023] The water phase non-ammonia denitrification agent of the waste incineration flue gas is sprayed into the waste incinerator to react with the NOx in the flue gas in the furnace to complete the flue gas denitrification treatment.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The waste incineration flue gas water phase non-ammonia denitrification agent of the present invention selects cheap raw materials as reducing agents, and can utilize the leachate in the garbage plant, etc., adopts specific components and proportions, and can be directly applied to the SNCR system to improve the denitrification efficiency, so that the denitrification efficiency reaches more than 80%, and the NOx content in the flue gas after denitrification is as low as 80mg / m 3 The above figure is better than the national emission standard. At the same time, the use of this denitrification agent can also effectively solve the problem of high ammonia slip in the SNCR system.

[0026] The waste incineration flue gas water phase non-ammonia denitrification agent of the present invention is prepared by using cheap raw materials, has low cost, and has a simple preparation method. When used, the original SNCR process equipment can be used to further reduce the denitrification cost. DETAILED DESCRIPTION

[0027] The waste incineration flue gas water phase non-ammonia denitrification agent of the present invention comprises the following components in parts by weight:

[0028] 40-80 parts of liquid carbon source;

[0029] 5-15 parts of alcohol compound;

[0030] 5 to 10 parts of additives.

[0031] The waste incineration flue gas water-phase non-ammonia denitrification agent provided by the present invention adopts specific ingredients and ratios and is evenly sprayed into the waste incinerator. The sprayed liquid carbon source and alcohol compounds are further decomposed into hydrocarbons, mixed with the flue gas, and subjected to reduction reaction in the flue, thereby overcoming the defects of the existing SNCR system such as low denitrification efficiency and high ammonia escape. In the three flues, horizontal flues and economizer flues of waste incineration, that is, in the temperature range of 200°C to 800°C, NOx is further reduced and reduced, thereby ensuring a higher denitrification efficiency. The use of this denitrification agent can stably control NOx at 80mg / m 3 The level below is far below the national emission standards.

[0032] In one embodiment of the present invention, the liquid carbon source is a small molecule short-chain hydrocarbon.

[0033] In one embodiment of the present invention, the small molecule short chain hydrocarbons are derived from at least one of the leachate after anaerobic treatment of landfill, biogas slurry after anaerobic treatment of food waste, filtrate of domestic waste, and C5-C18 hydrocarbons.

[0034] In one embodiment of the present invention, the alcohol compound is a C1-C8 monohydric alcohol or a polyhydric alcohol.

[0035] In one embodiment of the present invention, the C1-C8 monohydric alcohol or polyhydric alcohol is at least one of methanol, ethanol, isopropanol, n-butanol, ethylene glycol, and glycerol.

[0036] In one embodiment of the present invention, the additive is at least one of sodium carboxymethyl cellulose, Tween-80, unsaturated branched alcohol and branched alcohol polyoxyethylene ether.

[0037] In one embodiment of the present invention, the unsaturated branched alcohol is 2,4,7,9-tetramethyl-5-decyne-4,7-diol; and the branched alcohol polyoxyethylene ether is isomeric decanol polyoxyethylene ether.

[0038] In one embodiment of the present invention, the following components are also included in parts by weight: 20 to 60 parts of water. That is, the waste incineration flue gas water phase non-ammonia denitrification agent includes the following components in parts by weight: 40 to 80 parts of liquid carbon source; 5 to 15 parts of alcohol compound; 5 to 10 parts of additive; and 20 to 60 parts of water.

[0039] The invention also provides the use of a water-phase non-ammonia denitrifier for waste incineration flue gas in SNCR.

[0040] The waste incineration flue gas water phase non-ammonia denitrification agent of the present invention can be applied to SNCR to further reduce the emission of nitrogen oxides. The denitrification agent can be sprayed into the waste incinerator using an independent mixing, metering, distribution, and atomization injection system; or the existing SNCR equipment of the waste incineration plant can be used to complete the transportation, metering, distribution, and spraying atomization process of the denitrification agent.

[0041] In one embodiment of the present invention, a non-ammonia denitrifier in the water phase of waste incineration flue gas is sprayed into a waste incinerator to react with NOx in the flue gas in the furnace to complete the flue gas denitrification treatment. The use of the denitrifier can utilize the existing SNCR equipment to further reduce costs.

[0042] The present invention is further described below with specific examples, but the embodiments of the present invention are not limited thereto.

[0043] Example 1

[0044] The raw material composition of the water phase non-ammonia denitrifier for waste incineration flue gas is as follows:

[0045] Water: 40 parts; anaerobic post-leachate from landfill: 40 parts; methanol: 15 parts; isomeric decanol polyoxyethylene ether: 5 parts.

[0046] Preparation method: Mix the above raw materials evenly.

[0047] Example 2

[0048] The raw material composition of the water phase non-ammonia denitrifier for waste incineration flue gas is as follows:

[0049] Water: 40 parts; anaerobic post-leachate from landfill: 45 parts; methanol: 10 parts; isomeric decanol polyoxyethylene ether: 5 parts.

[0050] Preparation method: Mix the above raw materials evenly.

[0051] Example 3

[0052] The raw material composition of the water phase non-ammonia denitrifier for waste incineration flue gas is as follows:

[0053] Water: 40 parts; domestic waste filtrate: 40 parts; methanol: 15 parts; isomeric decanol polyoxyethylene ether: 5 parts.

[0054] Preparation method: Mix the above raw materials evenly.

[0055] Example 4

[0056] The raw material composition of the water phase non-ammonia denitrifier for waste incineration flue gas is as follows:

[0057] Water: 40 parts; landfill anaerobic post-leachate: 40 parts; methanol: 15 parts; 2,4,7,9-tetramethyl-5-decyne-4,7-diol: 5 parts.

[0058] Preparation method: Mix the above raw materials evenly.

[0059] Example 5

[0060] The raw material composition of the water phase non-ammonia denitrifier for waste incineration flue gas is as follows:

[0061] Water: 40 parts; anaerobic landfill leachate: 40 parts; ethanol: 15 parts; 2,4,7,9-tetramethyl-5-decyne-4,7-diol: 5 parts.

[0062] Preparation method: Mix the above raw materials evenly.

[0063] Comparative Example 1

[0064] According to the commonly used SNCR system, the reducing agent is configured, and the specific ratio is as follows:

[0065] Water: 80 parts; Urea: 20 parts; Mix thoroughly and stir evenly.

[0066] Test Example 1

[0067] The denitrification agents of the above embodiments and comparative examples are applied to specific flue gas treatment. The flue gas to be treated is waste incineration flue gas. The daily incineration capacity of the mechanical grate furnace waste incineration line is 500 tons of domestic waste, the flue gas volume is 90,000-110,000 m3 / hr, and the original NOx concentration is 200-350 mg / Nm 3 The main component of NOx in flue gas is NO, accounting for more than 95% of NOx, and the rest is NO2, etc. The denitrification agent is evenly sprayed into the first and second flues of the incinerator at a temperature of 800℃~1100℃, mixed with the flue gas for reaction, and the NOx concentration in the flue gas before and after treatment is detected by the flue gas analyzer, and the NOx removal rate is calculated. The results are shown in Table 1.

[0068] Table 1

[0069]

[0070] By comparing the water-phase denitrifier of the present invention with the traditional SNCR through the data in the table, it can be clearly seen that the application of the water-phase denitrifier of the present invention can improve the denitrification efficiency and reduce ammonia escape.

[0071] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A non-ammonia denitrifier for waste incineration flue gas water phase, characterized in that: Contains the following components in parts by weight: 40-80 parts of liquid carbon source; 5-15 parts of alcohol compound; 5 to 10 parts of additives.

2. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 1, characterized in that: The liquid carbon source is a small molecule short-chain hydrocarbon.

3. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 2, characterized in that: The small molecule short chain hydrocarbons are derived from at least one of the leachate after anaerobic treatment of landfill, biogas slurry after anaerobic treatment of kitchen waste, filtrate of domestic waste, and C5-C18 hydrocarbons.

4. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 1, characterized in that: The alcohol compound is a C1-C8 monohydric alcohol or a polyhydric alcohol.

5. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 4, characterized in that: The C1-C8 monohydric alcohol or polyhydric alcohol is at least one of methanol, ethanol, isopropanol, n-butanol, ethylene glycol, and glycerol.

6. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 1, characterized in that: The additive is at least one of sodium carboxymethyl cellulose, Tween-80, unsaturated branched alcohol and branched alcohol polyoxyethylene ether.

7. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 6, characterized in that: The unsaturated branched alcohol is 2,4,7,9-tetramethyl-5-decyne-4,7-diol; and the branched alcohol polyoxyethylene ether is isomeric decanol polyoxyethylene ether.

8. The waste incineration flue gas water phase non-ammonia denitrification agent according to claim 1, characterized in that: The invention also comprises the following components in parts by weight: 20 to 60 parts of water.

9. Use of the non-ammonia denitrification agent for water phase of waste incineration flue gas according to any one of claims 1 to 8 in SNCR.

10. The use of the non-ammonia denitrification agent for water phase of waste incineration flue gas in SNCR according to claim 9, characterized in that: The steps include: The water phase non-ammonia denitrification agent of the waste incineration flue gas is sprayed into the waste incinerator to react with the NOx in the flue gas in the furnace to complete the flue gas denitrification treatment.

Images