阅读说明：本技术 有价二次物料处置过程中产生烟气的处理方法 (Treatment method for smoke generated in valuable secondary material treatment process ) 是由 施自恩 施自意 沈建国 于 2021-09-30 设计创作，主要内容包括：本发明提供了有价二次物料处置过程中产生烟气的处理方法,包括以下步骤：1)烟气预除尘；2)对烟气温度可控制式随机冷却降温,通过喷入生石灰粉和活性炭粉进行半干法脱硫；3)采用一级布袋除尘器收集下来的烟灰循环使用；4)采用蓄热式焚烧炉对烟气进行二次燃烧,并在燃烧室内喷入尿素溶液,采用SNCR方法进行脱硝；5)将后续烟气与蓄热式焚烧炉出来烟气进行热交换,将进入烟囱的烟气提升至120℃以上；6)向烟气中快速喷入活性炭,使活性炭和烟气充分混合,再通过二级布袋除尘器去除活性炭粉；7)采用氢氧化钠溶液或碳酸钠溶液进行二级脱硫；8)对二级脱硫后的烟气进行强化脱硫补充。本发明实现了高效、节能、环保、超净排放。(The invention provides a method for treating smoke generated in the treatment process of valuable secondary materials, which comprises the following steps: 1) pre-dedusting the flue gas; 2) randomly cooling the flue gas with controllable temperature, and spraying quicklime powder and activated carbon powder to perform semi-dry desulfurization; 3) recycling the soot collected by the primary bag-type dust collector; 4) carrying out secondary combustion on the flue gas by adopting a heat accumulating type incinerator, spraying a urea solution into a combustion chamber, and carrying out denitration by adopting an SNCR (selective non-catalytic reduction) method; 5) carrying out heat exchange between the subsequent flue gas and the flue gas discharged from the heat accumulating type incinerator, and raising the temperature of the flue gas entering a chimney to be above 120 ℃; 6) quickly spraying activated carbon into the flue gas to fully mix the activated carbon with the flue gas, and removing activated carbon powder by a secondary bag-type dust collector; 7) performing secondary desulfurization by using a sodium hydroxide solution or a sodium carbonate solution; 8) and carrying out reinforced desulfurization supplementation on the flue gas subjected to secondary desulfurization. The invention realizes high efficiency, energy saving, environmental protection and ultra-clean discharge.)

1. The treatment method of the smoke generated in the valuable secondary material treatment process comprises the following steps:

1) pre-dedusting the flue gas by adopting a settling chamber;

2) randomly cooling the flue gas with controllable temperature, and spraying quicklime powder and activated carbon powder to perform semi-dry desulfurization after the temperature is reduced to 220-240 ℃;

3) collecting soot including soot, unreacted lime powder, desulfurized slag and activated carbon powder by using a primary bag-type dust collector, and recycling the collected soot;

4) carrying out secondary combustion on the flue gas by adopting a heat accumulating type incinerator, heating to above 800 ℃, spraying a urea solution into a combustion chamber, and carrying out denitration by adopting an SNCR (selective non-catalytic reduction) method;

5) carrying out heat exchange between the subsequent flue gas and the flue gas discharged from the heat accumulating type incinerator, and raising the temperature of the flue gas entering a chimney to be above 120 ℃;

6) quickly spraying activated carbon into the flue gas to fully mix the activated carbon with the flue gas, and removing activated carbon powder by a secondary bag-type dust collector;

7) performing secondary desulfurization by using a sodium hydroxide solution or a sodium carbonate solution;

8) and the flue gas after the secondary desulfurization is supplemented with enhanced desulfurization, so that the ultra-clean emission of the flue gas is ensured.

2. The method for treating the smoke generated in the valuable secondary material disposal process according to claim 1, wherein in the step 1), a large-volume settling chamber with the volume not less than 90 cubic meters is adopted for pre-dedusting the smoke.

3. The method for treating the flue gas generated in the secondary valuable material disposal process according to claim 1, wherein in the step 2), a controllable aqueous medium surface cooler is adopted to carry out controllable random cooling on the temperature of the flue gas.

4. The method for treating the smoke generated in the valuable secondary material disposal process according to claim 1 or 3, wherein in the step 2), the quicklime powder is prepared into a 10% lime milk solution.

5. The method for treating the flue gas generated in the valuable secondary material disposal process according to claim 1, wherein in the step 3), the collected soot is recycled to the ball/brick making system for recycling.

6. The method for treating the smoke generated in the secondary valuable material disposal process according to claim 1, wherein the step 4) comprises the step of rapidly cooling the smoke from 800 ℃ to 200 ℃ within 2s by using a rapid cooling function of an efficient heat storage process of an internal honeycomb ceramic tile.

7. The method for treating the smoke generated in the valuable secondary material disposal process according to claim 1, wherein in the step 4), a 10% urea solution is used.

8. The method for treating the flue gas generated in the valuable secondary material disposal process according to claim 1, wherein in the step 7), the secondary desulfurization is performed in a double alkali desulfurization tower, and the sodium hydroxide solution is a 10% sodium hydroxide solution.

9. The method for treating the smoke generated in the valuable secondary material disposal process according to claim 1 or 8, wherein the step 7) further comprises the following steps: the desulfurized liquid is regenerated by calcium oxide, and the desulfurized gypsum is used as a byproduct after being refined.

10. The method for treating the smoke generated in the valuable secondary material disposal process according to claim 1, wherein the primary bag-type dust remover and the secondary bag-type dust remover are both pulse bag-type dust removers.

Technical Field

The invention belongs to the technical field of environmental protection flue gas treatment, and particularly relates to a method for treating flue gas generated in a valuable secondary material treatment process.

Background

The valuable secondary materials such as copper-containing sludge, nickel-containing sludge, electronic waste and the like have complex components, contain various metals and organic matters, face two problems of environmental pollution and comprehensive recovery in the treatment process, and the main treatment process comprises two kinds of processes, namely a fire process and a wet process:

the pyrogenic process comprises the traditional closed oxygen-enriched side-blown furnace method, rotary incinerator method, top-blown furnace method and the like, and the flue gas is treated by adopting a tilted flue, an ash settling barrel, an air heat exchange surface cooler, a cloth bag dust collection, an alkaline process (calcium, sodium, magnesium and the like are used as desulfurizing agents) for desulfurization and chimney emission. A combustion chamber is additionally arranged in front of the inclined flue, and the time for combustion supporting and temperature rising by fuel is more than 800 ℃ and is reserved for more than 2s to promote the decomposition of dioxin (PCDD/Fs) substances, and then the dioxin (PCDD/Fs) substances are prevented from being resynthesized by quenching to 200 ℃ in 2 s; thus, although the emission of dioxin (PCDD/Fs) substances which basically reach the standard can be met, the heat energy loss is large, and the energy is not saved and is not economical.

The wet recovery method is to utilize mediums such as strong inorganic acid, strong alkali and the like to leach valuable secondary materials such as copper-containing sludge, nickel-containing sludge, electronic wastes and the like, so that most metals (including precious metals and base metals) in the valuable secondary materials such as the copper-containing sludge, the nickel-containing sludge, the electronic wastes and the like are dissolved and enter a liquid phase, and then the precious metals and other base metals are recovered from the liquid phase.

Disclosure of Invention

The invention aims to provide a method for treating flue gas generated in the process of treating valuable secondary materials, which is efficient, energy-saving, environment-friendly and ultra-clean in emission, aiming at the problems in the prior art.

In order to achieve the purpose, the invention adopts the technical scheme that:

the treatment method of the smoke generated in the valuable secondary material treatment process comprises the following steps:

1) pre-dedusting the flue gas by adopting a settling chamber;

2) randomly cooling the flue gas with controllable temperature, and spraying quicklime powder and activated carbon powder to perform semi-dry desulfurization after the temperature is reduced to 220-240 ℃;

3) collecting soot including soot, unreacted lime powder, desulfurized slag and activated carbon powder by using a primary bag-type dust collector, and recycling the collected soot;

4) carrying out secondary combustion on the flue gas by adopting a heat accumulating type incinerator, heating to above 800 ℃, spraying a urea solution into a combustion chamber, and carrying out denitration by adopting an SNCR (selective non-catalytic reduction) method;

5) carrying out heat exchange between the subsequent flue gas and the flue gas discharged from the heat accumulating type incinerator, and raising the temperature of the flue gas entering a chimney to be above 120 ℃;

6) quickly spraying activated carbon into the flue gas to fully mix the activated carbon with the flue gas, and removing activated carbon powder by a secondary bag-type dust collector;

7) performing secondary desulfurization by using a sodium hydroxide solution or a sodium carbonate solution;

8) and the flue gas after the secondary desulfurization is supplemented with enhanced desulfurization, so that the ultra-clean emission of the flue gas is ensured.

Preferably, in the step 1), a large-volume settling chamber with the volume not less than 90 cubic meters is adopted for pre-dedusting the flue gas.

Preferably, in the step 2), a controllable aqueous medium surface cooler is adopted to carry out controllable random cooling on the temperature of the flue gas.

Preferably, the quicklime powder is prepared into a 10% lime milk solution.

Preferably, in the step 3), the collected soot is recycled to the ball/brick making system for recycling.

Preferably, the step 4) comprises the step of rapidly cooling the flue gas temperature from above 800 ℃ to below 200 ℃ within 2s by the rapid cooling function of the internal honeycomb ceramic tile high-efficiency heat storage process.

More preferably, in step 4), a 10% urea solution is used.

Preferably, in the step 7), the secondary desulfurization is carried out in a double-alkali desulfurization tower, and the sodium hydroxide solution is 10% sodium hydroxide solution.

Preferably, step 7) further comprises: the desulfurized liquid is regenerated by calcium oxide, and the desulfurized gypsum is used as a byproduct after being refined.

Preferably, the primary bag-type dust collector and the secondary bag-type dust collector are both pulse bag-type dust collectors.

The invention has the following beneficial effects:

1. and a large-volume settling chamber is adopted, so that the flow velocity of flue gas is reduced, and the dust removal effect is improved.

2. The controllable water medium surface cooler is adopted to cool the temperature of the flue gas to the required temperature at random in a controllable way.

3. The semi-dry method is adopted for desulfurization, the temperature of the flue gas is controlled, the operation is stable, and the operating environment is good; quicklime powder and active carbon are sprayed, so that peculiar smell can be absorbed quickly and a cloth bag of a dust collector is protected.

4. The pulse bag dust collector is adopted to collect smoke dust, unreacted lime powder, desulfurized slag, a small amount of activated carbon powder and the like, the collected soot is recycled to a ball (brick) making system for recycling, and the flue gas dust removal rate reaches more than 99%.

5. The heat accumulating type high-temperature incinerator (RTO) is adopted, the energy consumption is low, the temperature can be rapidly reduced while heat accumulation is carried out, and the urea solution is sprayed into the high-temperature combustor to realize denitration and dioxin removal synchronously.

6. The smoke heat exchanger is adopted, and the waste heat of the smoke at the outlet of the heat accumulating type high temperature incinerator (RTO) is fully utilized, so that the aim of white elimination is fulfilled.

7. Activated carbon is quickly sprayed into the flue gas through the activated carbon spraying device, so that the activated carbon and the flue gas are fully mixed, and a better dioxin and peculiar smell absorption effect is achieved.

8. After activated carbon powder is sprayed into flue gas discharged from a heat accumulating type incinerator (RTO), a secondary bag-type dust remover is adopted to remove the flue gas, and the activated carbon powder is attached to the surface of a bag when the flue gas passes through the bag, so that the effect of absorbing dioxin and peculiar smell is further improved.

9. Because the semi-dry desulfurization efficiency does not meet the emission requirement, 10 percent sodium hydroxide solution or sodium carbonate solution is adopted in the alkaline desulfurization tower for secondary desulfurization. The desulfurized liquid is regenerated by calcium oxide, and the desulfurized gypsum is used as a byproduct after being refined.

10. And the flue gas discharged from the dual-alkali desulfurization tower is supplemented with enhanced desulfurization, so that ultra-clean emission of the flue gas is ensured.

Drawings

FIG. 1 is a flow chart of the process for treating the flue gas of the oxygen-enriched side-blown smelting furnace.

Detailed Description

In order to more clearly illustrate the present invention, the present invention will be described in further detail below with reference to examples and the accompanying drawings. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

With reference to fig. 1, the method for treating flue gas generated in the valuable secondary material disposal process mainly comprises the following steps:

(1) pre-dedusting of flue gas: aiming at the characteristics of large concentration of smoke dust and easy blockage of a flue of the smelting furnace, the large-volume settling chamber with the volume not less than 90 cubic meters is adopted, the flow velocity of the smoke gas is reduced, the dust removal effect is improved, the dust removal efficiency reaches 55-60%, and the temperature of the smoke gas is 400-500 ℃.

(2) Controllable aqueous medium surface cooler: the temperature of the flue gas can be controlled and randomly cooled to 220-240 ℃, and then the flue gas enters a semi-dry desulfurization tower.

(3) Semi-dry desulfurization tower: the flue gas is desulfurized in the first stage, the flue gas is contacted with lime cream by spraying 10 percent of lime cream solution, and then the activated carbon powder is sprayed, so that the desulfurization efficiency is 65 to 70 percent, and the outlet temperature is about 170 ℃.

(4) Quicklime powder and active carbon injection device: controlling the moisture of the smoke and absorbing the peculiar smell of the smoke, and protecting the dust removal cloth bag.

(5) A primary bag-type dust collector: the pulse bag dust collector is adopted to collect smoke dust, unreacted lime powder, desulfurized slag, a small amount of activated carbon powder and the like, the collected soot is recycled to a ball (brick) making system for recycling, and the flue gas dust removal rate reaches more than 99%.

(6) Regenerative high temperature incinerator (RTO): through a primary bag-type dust collector, the temperature of outlet flue gas is 130-150 ℃, the flue gas enters a Regenerative Thermal Oxidizer (RTO), secondary combustion heating is carried out on the flue gas to be more than 800 ℃, basic decomposition of dioxin (PCDD/Fs) substances in the flue gas is ensured, 10% urea solution is sprayed into a combustion chamber, denitration is carried out by adopting an SNCR method, synchronous realization of denitration and dioxin removal is realized, meanwhile, through the rapid cooling function of an internal honeycomb ceramic tile efficient heat storage process, on one hand, the heat energy of the heated flue gas is fully recycled, the fuel cost is greatly reduced, the energy-saving efficiency can reach more than 95%, on the other hand, the temperature of the flue gas can be ensured to be suddenly cooled to be below 200 ℃ from more than 800 ℃ within 2s, the resynthesis of the dioxin (PCDD/Fs) substances in the flue gas can be effectively reduced, and the standard emission of the dioxin (PCDD/Fs) substances is ensured.

(7) A heat exchanger: the temperature of the flue gas discharged from the heat accumulating type incinerator (RTO) is 200-220 ℃, and considering that the subsequent desulfurization adopts wet desulfurization, the temperature of the flue gas can be reduced to below 60 ℃, the humidity of the flue gas is high, white smoke is easy to generate, further, waste heat utilization is carried out, the subsequent flue gas and the flue gas discharged from the heat accumulating type incinerator are subjected to heat exchange, the temperature of the flue gas entering a chimney is increased to above 120 ℃, and the aim of white smoke elimination is achieved.

(8) Activated carbon injection apparatus: activated carbon is quickly sprayed into the flue gas through the activated carbon spraying device, so that the activated carbon and the flue gas are fully mixed, and a better dioxin and peculiar smell absorption effect is achieved.

(9) A second-stage bag-type dust collector: after the flue gas is sprayed with the activated carbon powder, the flue gas is removed by a secondary bag-type dust collector (the same as the pulse-type bag-type dust collector adopted in the step (5)), and the activated carbon powder is attached to the surface of the bag when the flue gas passes through the bag, so that the effect of absorbing dioxin and peculiar smell is improved.

(10) A double-alkali desulfurization tower: because the semi-dry desulfurization efficiency does not meet the requirement, 10 percent sodium hydroxide solution or sodium carbonate solution is adopted in the alkaline desulfurization tower for secondary desulfurization. The desulfurized liquid is regenerated by calcium oxide, and the desulfurized gypsum is used as a byproduct after being refined.

(11) Alkaline washing tower: and the flue gas from the dual-alkali desulfurization tower is supplemented by enhanced desulfurization, so that ultra-clean emission of the flue gas is ensured.

Examples

The embodiment of the present invention will be further explained by taking a certain oxygen-rich smelting furnace plant which processes 120 tons of hazardous wastes such as copper-containing and nickel-containing sludge and electronic wastes daily as an example.

Dangerous wastes such as ton bag package copper, nickel-containing sludge and electronic wastes after quintuplet single filing are transported by a material transporting vehicle to enter a factory dangerous waste temporary storage for temporary storage, a ball/brick making workshop leads out the materials according to various content requirement proportions, the materials are mixed, stored, dried and made into a ball/brick shape, fuel and flux with a certain proportion are put into an oxygen-enriched smelting furnace in sequence, oxygen produced by an oxygen production station is mixed with air of a Roots blower and then blown into the smelting furnace, the temperature of a focus area in the furnace is controlled between 1200 ℃ and 1400 ℃, the temperature of flue gas at a furnace shell outlet is between 380 ℃ and 450 ℃, and the actual flue gas quantity measured by a pore plate flowmeter is 15000Am³Hr, particulate matter concentration 25480mg/Nm³Sulfur dioxide concentration of 1850mg/Nm³Nitric oxide concentration 1280mg/Nm³Dioxin 2.5ngTEQ/Nm³。

Under the action of a strong draught fan, the furnace charging opening keeps micro negative pressure so as not to make the flue gas externally emit, and the flue gas sequentially passes through a large-volume settling chamber, a controllable water medium surface cooler, a semi-dry desulfurization tower, a primary pulse bag-type dust remover, a heat accumulating type high-temperature incinerator (RTO), a flue gas heat exchanger, a secondary pulse bag-type dust remover, a double-alkali desulfurization tower and a reinforced alkali washing tower. The flue gas passes through a large-volume settling chamber, and the actual measured particulate matter concentration is 11250mg/Nm³The removal rate of the large-volume settling chamber to the particulate matters can reach 55.8 percent; taking 10% lime milk as desulfurizer to desulfurize in a semidry desulfurization tower, and sampling and actually measuring the sulfur dioxide concentration at the outlet of the semidry desulfurization tower to be 550mg/Nm³The sulfur dioxide removal rate reaches 70.3 percent, and the sulfur dioxide is subjected to primary pulse type cloth bag dust removalSampling and actually measuring the concentration of particulate matters to be 29.8mg/Nm after urea is sprayed into a Regenerative Thermal Oxidizer (RTO) for denitration³Nitric oxide concentration 50mg/Nm³Dioxin concentration 0.3ngTEQ/Nm³The particulate removal rate reaches 99.7%, the nitrogen oxide removal rate reaches 96.1%, and the dioxin removal rate reaches 88%, and activated carbon is sprayed into the flue gas by an activated carbon spraying device arranged on a pipeline in front of a secondary pulse type bag-type dust collector behind a heat accumulating type high-temperature incinerator (RTO) and a flue gas heat exchanger so as to adsorb a small amount of dioxin-like substances newly synthesized in the quenching process of the flue gas and further improve the removal rate of the dioxin. The removal rate is further improved through a secondary pulse bag-type dust collector, a double-alkali-method desulfurizing tower and an enhanced alkali-method washing tower, and ultra-clean emission of flue gas is ensured.

The flue gas heat exchanger is finally discharged in high altitude through a chimney of 60 meters, an online monitoring system is arranged on the chimney of 60 meters to monitor various emission indexes of the discharged flue gas in real time, and the 24-hour real-time monitoring data of a discharge port is as follows: the flue gas temperature is 120 ℃, and the flue gas quantity is 9000Am³In/hr (operating condition), the concentration of particulate matter is 5-10mg/Nm³The concentration of sulfur dioxide is 10-30mg/Nm³The concentration of nitrogen oxide is 30-50mg/Nm³Measuring the concentration of dioxin in the discharge outlet by suction at 0.05ngTEQ/Nm³The removal rate of particulate matter reaches 99.9%, the removal rate of sulfur dioxide reaches 98.5%, the removal rate of nitrogen oxide reaches 96.1%, and the removal rate of dioxin reaches 98%.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all the embodiments of the present invention are not exhaustive, and all the obvious variations or modifications which are introduced in the technical scheme of the present invention are within the scope of the present invention.