Plasma fly ash melting treatment system and method combined with waste incineration power plant

Abstract

The present invention discloses a plasma fly ash melting treatment system and method combined with a waste incineration power plant, including a waste treatment system and a fly ash treatment system; the waste treatment system includes a waste storage pit, a waste incinerator, a waste heat boiler, a semi-dry reaction tower, a bag filter and a fan arranged in sequence, and the semi-dry reaction tower and the bag filter are connected through a flue gas duct; the fly ash treatment system includes a fly ash collection bin, a fly ash forming system, a plasma melting furnace, a secondary combustion chamber, a wet deacidification tower and an electrostatic precipitator arranged in sequence, and the fly ash collection bin collects the fly ash in the semi-dry reaction tower and the bag filter and the flue gas duct between them, and the outlet of the electrostatic precipitator is connected to the fan. The present invention changes the composition of the waste fly ash by changing the deacidification agent composition of the waste incineration power plant, thereby solving the problems of high energy consumption in the melting process and high chlorine content in the vitreous body.

Description

Technical Field

[0001] The present invention relates to the technical field of waste fly ash treatment, and in particular to a plasma fly ash melting treatment system and method combined with a waste incineration power plant. Background Art

[0002] Waste incineration fly ash contains flue gas entrained particles, deacidification products and excess chemical agents. At present, the main agent used for deacidification is quicklime, which has the advantages of large surface area and low processing cost. However, the use of quicklime as a dry and semi-dry removal agent is inefficient, and it is easy to spray in excess agents, which increases the amount of fly ash produced. During the fly ash melting process, a large amount of calcium-based deacidification agents are sprayed in the deacidification process, which leads to an increase in the melting temperature of the fly ash, wasting energy and affecting economic costs. The CaCl generated by deacidification 2 The volatilization temperature of the substance reaches 1600℃, so some CaCl 2 The substance cannot volatilize and remain in the vitreous body, and the remaining substance will affect the resource utilization of the vitreous body as a building material. Summary of the invention

[0003] The purpose of the present invention is to make up for the defects of the existing technology and provide a plasma fly ash melting treatment system and method combined with a waste incineration power plant. By changing the composition of the deacidification agent of the waste incineration power plant and thus changing the composition of the waste fly ash, the problems of high energy consumption in the melting process and high chlorine content in the glass are solved.

[0004] The present invention is achieved through the following technical solutions:

[0005] A plasma fly ash melting treatment system and method combined with a waste incineration power plant, comprising a waste treatment system and a fly ash treatment system;

[0006] The garbage disposal system comprises a garbage storage pit, a garbage incinerator, a waste heat boiler, a semi-dry reaction tower, a bag dust collector and a fan which are arranged in sequence, and the semi-dry reaction tower and the bag dust collector are connected through a flue gas pipeline;

[0007] The fly ash treatment system includes a fly ash collection bin, a fly ash forming system, a plasma melting furnace, a secondary combustion chamber, a wet deacidification tower and an electrostatic precipitator which are arranged in sequence. The fly ash collection bin collects fly ash in the semi-dry reaction tower and the bag filter and in the flue gas duct therebetween. The outlet of the electrostatic precipitator is connected to the fan.

[0008] A CEMS real-time monitoring system is installed at the smoke exhaust port of the fan and in the fly ash collection bin.

[0009] A sodium bicarbonate injection device and an activated carbon injection device are arranged in sequence on the flue gas pipeline between the semi-dry reaction tower and the bag filter.

[0010] The water outlet of the wet deacidification tower is connected with a wastewater treatment device.

[0011] A plasma fly ash melting treatment method combined with a waste incineration power plant specifically comprises the following steps:

[0012] (1) After the garbage is collected at the incineration plant, it is poured into the garbage pit. After fermentation in the garbage pit, the garbage is put into the garbage incinerator for combustion. The flue gas generated first passes through the waste heat boiler for heat exchange;

[0013] (2) The flue gas after heat exchange and cooling in the waste heat boiler is introduced into the semi-dry reaction tower, where lime slurry is sprayed to remove the acid gas; in order to reduce the amount of fly ash produced and change the composition of fly ash to lower the melting point of fly ash, and at the same time, to take out the chlorine element during the melting process of fly ash, sodium bicarbonate is sprayed into the flue gas pipeline;

[0014] (3) In order to ensure that the emission of acidic gases and heavy metals in the flue gas meets the standards, 1‰-4‰ activated carbon is sprayed into the flue gas duct in front of the bag filter for adsorption. All dust will be intercepted in the bag filter, and the flue gas purified by the bag filter is discharged through the fan;

[0015] (4) The fly ash intercepted by the semi-dry reaction tower and bag filter is collected in the fly ash collection bin, and the collected fly ash and additives are made into granular materials in the fly ash molding system at a ratio of 10:1.5~3;

[0016] (5) The particulate matter is directly transported to the plasma melting furnace, where the electric arc provides energy to melt the particulate matter. The molten matter is rapidly cooled to become a glassy body, and the volatile matter enters the secondary combustion chamber along with the flue gas.

[0017] (6) The flue gas first burns part of the combustible gas in the secondary combustion chamber, and then the acid gas is removed by sodium hydroxide in the wet deacidification tower. The reagent content is that the molar ratio of sodium hydroxide to chlorine and sulfur is controlled at 2~5:1. The particulate matter that is not captured will be retained in the electrostatic precipitator. The wastewater generated by the wet deacidification tower is treated by the wastewater treatment device. The purified flue gas is injected into the pipeline in front of the fan of the waste incineration power plant and discharged into the atmosphere along with the purified flue gas from the waste incineration power plant.

[0018] The contents of the reagents sprayed into the semi-dry reaction tower are a molar ratio of sodium bicarbonate to chlorine and sulfur of 1:1, a calcium-sulfur ratio of 1:1, and a calcium-chlorine ratio of 1:2.

[0019] The additive in step (4) is a silicon-containing substance.

[0020] In order to ensure that the flue gas emissions meet the standards, a CEMS real-time monitoring system is installed at the fan flue gas outlet and in the fly ash collection bin. The chlorine content in the vitreous body depends on the composition of the fly ash from the waste incineration, so periodic sampling is required to detect the fly ash and vitreous body components.

[0021] During operation, if the CEMS real-time monitoring system alarms and the composition of the waste incineration fly ash is appropriate, the injection amount of sodium bicarbonate will be increased until the flue gas emissions meet the requirements; if the flue gas emissions are normal, but the composition of the waste incineration fly ash is not appropriate, ensure that the flue gas emissions meet the requirements, increase the injection amount of sodium bicarbonate, reduce the injection amount of calcium hydroxide, or add a small amount of sodium bicarbonate to the additive and bring it into the plasma melting furnace; if both the flue gas emissions and the waste incineration fly ash composition are abnormal, first increase the injection amount of sodium bicarbonate, if it is still abnormal, increase the injection amount of calcium hydroxide until it is normal.

[0022] The advantages of the present invention are:

[0023] 1. Reduce the amount of fly ash generated by garbage incineration. The existing dry and semi-dry methods use calcium agents with low efficiency. Excess calcium will exist in the fly ash from garbage incineration, increasing the amount of fly ash generated and the cost of fly ash treatment. The use of sodium bicarbonate has high efficiency, which leads to a reduction in fly ash generation.

[0024] 2. By adding sodium bicarbonate, the chemical ratio of waste incineration fly ash can be changed to be more suitable for high-temperature melting, the melting temperature can be lowered, and the resulting glass body is more in line with the requirements of resource utilization, reducing the treatment cost of waste incineration fly ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural flowchart of the workflow of the present invention. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, a plasma fly ash melting treatment system and method combined with a waste incineration power plant includes a waste treatment system and a fly ash treatment system;

[0027] The garbage disposal system comprises a garbage storage pit 1, a garbage incinerator 2, a waste heat boiler 3, a semi-dry reaction tower 4, a bag filter 5 and a fan 6 which are arranged in sequence. The semi-dry reaction tower 4 and the bag filter 5 are connected via a flue gas duct 7.

[0028] The fly ash treatment system includes a fly ash collection bin 8, a fly ash molding system 9, a plasma melting furnace 10, a secondary combustion chamber 11, a wet deacidification tower 12 and an electrostatic precipitator 13 which are arranged in sequence. The fly ash collection bin 8 collects fly ash in the semi-dry reaction tower 4 and the bag filter 5 and the flue gas duct 7 therebetween. The outlet of the electrostatic precipitator 13 is connected to the fan 6.

[0029] A CEMS real-time monitoring system 14 is installed at the smoke exhaust port of the fan 6 and in the fly ash collection bin 8 .

[0030] The flue gas duct 7 between the semi-dry reaction tower 4 and the bag filter 5 is provided with a sodium bicarbonate injection device and an activated carbon injection device in sequence.

[0031] The water outlet of the wet deacidification tower 12 is connected to a wastewater treatment device 15 .

[0032] A plasma fly ash melting treatment method combined with a waste incineration power plant specifically comprises the following steps:

[0033] (1) After being collected by the sanitation system and delivered to the waste incineration plant, the garbage is dumped into the garbage storage pit 1. After fermentation in the garbage storage pit 1, the garbage is put into the waste incinerator 2 for combustion. The flue gas generated first passes through the waste heat boiler 3 for heat exchange to drive the steam turbine to generate electricity;

[0034] (2) Since the flue gas after cooling contains a large amount of acidic gas and heavy metals, the current mainstream process "dry method + semi-dry method" is adopted. In order to reduce the amount of fly ash produced and change the composition of fly ash to reduce the melting point of fly ash, and at the same time take out the chlorine element as much as possible during the melting process of fly ash, the dry method of deacidification sprays sodium bicarbonate into the flue gas pipeline, and the semi-dry reaction tower sprays lime slurry to remove the acidic gas; the content of the sprayed agent for dry deacidification is controlled at a molar ratio of sodium bicarbonate to chlorine and sulfur of 1:1~3, and the calcium-sulfur ratio in the semi-dry method is controlled at 1:1~3, and the calcium-chlorine ratio is 1:2~4;

[0035] (3) To ensure that the emission of acidic gases and heavy metals in the flue gas meets the standards, 1‰-4‰ (based on the amount of garbage processed) is sprayed into the front pipe of the bag filter. Activated carbon adsorption, all dust will be intercepted in the bag filter;

[0036] (4) The fly ash intercepted by the dry process, semi-dry reaction tower and bag filter will be collected in the fly ash collection tank. The collected fly ash and additives (mainly silicon-containing substances, sand, gravel, waste glass, etc.) are made into granular materials in the molding system at a ratio of 10:1.5~3;

[0037] (5) The particulate matter is directly transported to the melting furnace, where the electric arc provides energy to melt the mixture. The molten material is rapidly cooled to become a glass body and directly transported out for resource use. The volatile matter enters the subsequent flue gas treatment system along with the flue gas;

[0038] (6) The flue gas first burns part of the combustible gas in the secondary combustion chamber, and then the acid gas is removed by sodium hydroxide in the wet deacidification tower. The reagent content is that the molar ratio of sodium hydroxide to chlorine and sulfur is controlled at 2~5:1. The particulate matter that is not captured will be retained in the electrostatic precipitator. The wastewater is collected and treated. The treatment is similar to that of high-salt wastewater. The purified flue gas is injected into the pipeline in front of the fan of the waste incineration power plant and discharged into the atmosphere along with the purified flue gas from the waste incineration power plant.

[0039] (7) It is required that the flue gas emitted by waste incineration power plants meet the requirements of GB18485-2014, and the chlorine content in the vitreous must be less than 0.0025%. In order to ensure that the flue gas emissions meet the standards, a CEMS is installed at the flue gas outlet for real-time monitoring. The chlorine content in the vitreous depends on the composition of the fly ash from waste incineration, so periodic sampling is required to test the fly ash and vitreous components;

[0040] (8) During operation, if the CEMES alarm sounds and the composition of the waste incineration fly ash is appropriate, increase the amount of sodium bicarbonate injected until the flue gas emissions meet the requirements; if the flue gas emissions are normal but the composition of the waste incineration fly ash is not appropriate, ensure that the flue gas emissions meet the requirements, increase the amount of sodium bicarbonate injected, reduce the amount of calcium hydroxide injected, or add a small amount of sodium bicarbonate to the additive and bring it into the melting furnace; if both the flue gas emissions and the waste incineration fly ash composition are abnormal, first increase the amount of sodium bicarbonate injected. If it is still abnormal, increase the amount of calcium hydroxide injected until it returns to normal. Specific embodiment:

[0042] (1) After the garbage is collected by the sanitation system and dumped into the garbage storage pit, the garbage is fermented in the garbage storage pit and then put into the garbage incinerator for combustion. The flue gas generated first passes through the waste heat boiler for heat exchange to drive the steam turbine to generate electricity;

[0043] (2) Since the flue gas after cooling contains a large amount of acidic gas and heavy metals, the current mainstream process "dry method + semi-dry method" is adopted. In order to reduce the amount of fly ash produced and change the composition of fly ash to reduce the melting point of fly ash, and at the same time take out the chlorine element as much as possible during the melting process of fly ash, the dry method of deacidification sprays sodium bicarbonate into the flue gas pipeline, and the semi-dry reaction tower sprays lime slurry to remove the acidic gas; the content of the agent sprayed in the dry method of deacidification is controlled at a molar ratio of sodium bicarbonate to chlorine and sulfur of 1:1, and the calcium-sulfur ratio in the semi-dry method is controlled at 1:1, and the calcium-chlorine ratio is 1:2;

[0044] (3) To ensure that the emission of acidic gases and heavy metals in the flue gas meets the standards, 1‰ activated carbon adsorption (based on the amount of garbage processed) is sprayed into the front pipe of the bag filter, and all dust will be intercepted in the bag filter;

[0045] (4) The fly ash intercepted by the semi-dry reaction tower and bag filter will be collected in the fly ash collection tank. The collected fly ash and additives (mainly silicon-containing substances, sand, gravel, waste glass, etc.) are made into granular materials in the molding system at a ratio of 10:1.5;

[0046] (5) The particulate matter is directly transported to the melting furnace, where the electric arc provides energy to melt the mixture. The molten material is rapidly cooled by water spraying to become a vitreous body, which is directly transported out for resource use. The volatile matter enters the subsequent flue gas treatment system along with the flue gas;

[0047] (6) The flue gas will first burn part of the combustible gas in the secondary combustion chamber, and then sodium hydroxide solution will be sprayed into it to remove the acidic gas. The reagent content is that the molar ratio of sodium hydroxide to chlorine and sulfur is controlled at 3:1. The particulate matter that is not captured will be retained in the electrostatic precipitator. All collected wastewater will enter the wastewater treatment device. The treatment method can refer to high-salt wastewater. The purified flue gas is injected into the pipe in front of the fan of the waste incineration power plant and discharged into the atmosphere along with the purified flue gas from the waste incineration power plant.

[0048] (7) This process requires that the flue gas emitted by the waste incineration power plant meet the requirements of GB18485-2014, and the chlorine content in the produced glass must be less than 0.0025%. In order to ensure that the flue gas emissions meet the standards, a CEMS is installed at the flue gas outlet for real-time monitoring. The chlorine content in the glass depends on the composition of the fly ash from the waste incineration, so periodic sampling is required to detect the fly ash composition;

[0049] (8) During operation, if CEMES alarms and the composition of waste incineration fly ash is appropriate, increase the amount of sodium bicarbonate injected until the flue gas emissions meet the requirements, but the molar ratio of sodium bicarbonate to chlorine and sulfur cannot exceed 2:1. If it still exceeds the standard, increase the amount of calcium hydroxide injected. If the flue gas emissions are normal but the composition of waste incineration fly ash is not appropriate, ensure that the flue gas emissions meet the requirements, increase the amount of sodium bicarbonate injected, and achieve a molar ratio of sodium bicarbonate to chlorine and sulfur that does not exceed 1.5:1, reduce the amount of calcium hydroxide injected, and achieve a calcium-sulfur ratio of 0.7:1 and a calcium-chlorine ratio of 0.7:2 in the semi-dry method, or add a small amount of sodium bicarbonate to the additive and bring it into the melting furnace. If both the flue gas emissions and the composition of waste incineration fly ash are abnormal, first increase the amount of sodium bicarbonate injected, and the molar ratio of sodium bicarbonate to chlorine and sulfur cannot exceed 2:1. If it is still abnormal, increase the amount of calcium hydroxide injected until it returns to normal.

[0050] (9) This process considers the use of interlocking control, in which the CEMES flue gas emission value and the ratio of the original fly ash components Na2O, Al2O3, SiO2, and CaO are controlled at about 1.5:1:4:3.5, and the relevant acid agent injection control is initiated through the feedback information of the relationship between the two.

Claims

1. A plasma fly ash melting treatment method combined with a waste incineration power plant, characterized in that: The specific steps include: (1) After being collected at the incineration plant, the garbage is dumped into the garbage pit. After fermentation in the garbage pit, the garbage is put into the garbage incinerator for combustion. The flue gas generated is first heat exchanged by the waste heat boiler; (2) The flue gas after heat exchange and cooling in the waste heat boiler is introduced into the semi-dry reaction tower, where lime slurry is sprayed to remove the acid gas; in order to reduce the amount of fly ash produced and change the composition of fly ash to lower the melting point of fly ash, and at the same time, to take out the chlorine element during the melting process of fly ash, sodium bicarbonate is sprayed into the flue gas pipeline; (3) To ensure that the emission of acidic gases and heavy metals in the flue gas meets the standards, 1‰-4‰ activated carbon is sprayed into the flue gas duct in front of the bag filter for adsorption. All dust will be intercepted in the bag filter, and the flue gas purified by the bag filter is discharged through the fan; (4) The fly ash intercepted in the semi-dry reaction tower and the bag filter is collected in the fly ash collection bin, and the collected fly ash is mixed with additives at a ratio of 10:1.5~3 to form granular matter in the fly ash molding system; (5) The particulate matter is directly transported to the plasma melting furnace, where the electric arc provides energy to melt the particulate matter. The molten matter is rapidly cooled to become a glassy body, and the volatile matter enters the secondary combustion chamber along with the flue gas. (6) The flue gas first burns part of the combustible gas in the secondary combustion chamber, and then the acid gas is removed by sodium hydroxide in the wet deacidification tower. The reagent content is that the molar ratio of sodium hydroxide to chlorine and sulfur is controlled at 2~5:

1. The particulate matter that is not captured will be retained in the electrostatic precipitator. The wastewater generated by the wet deacidification tower is treated by the wastewater treatment device. The purified flue gas is injected into the pipeline in front of the fan of the waste incineration power plant and discharged into the atmosphere along with the purified flue gas of the waste incineration power plant; During operation, if the CEMS real-time monitoring system alarms and the composition of the waste incineration fly ash is appropriate, the injection amount of sodium bicarbonate will be increased until the flue gas emissions meet the requirements; if the flue gas emissions are normal, but the composition of the waste incineration fly ash is not appropriate, ensure that the flue gas emissions meet the requirements, increase the injection amount of sodium bicarbonate, reduce the injection amount of calcium hydroxide, or add a small amount of sodium bicarbonate to the additive and bring it into the plasma melting furnace; if both the flue gas emissions and the waste incineration fly ash composition are abnormal, first increase the injection amount of sodium bicarbonate, if it is still abnormal, increase the injection amount of calcium hydroxide until it is normal.

2. The plasma fly ash melting treatment method combined with a waste incineration power plant according to claim 1 is characterized in that: The contents of the reagents sprayed into the semi-dry reaction tower are a molar ratio of sodium bicarbonate to chlorine and sulfur of 1:1, a calcium-sulfur ratio of 1:1, and a calcium-chlorine ratio of 1:

2.

3. The plasma fly ash melting treatment method combined with a waste incineration power plant according to claim 1 is characterized in that: The additive in step (4) is a silicon-containing substance.

4. The plasma fly ash melting treatment method combined with a waste incineration power plant according to claim 1 is characterized in that: In order to ensure that the flue gas emissions meet the standards, a CEMS real-time monitoring system is installed at the fan flue gas outlet and in the fly ash collection bin. The chlorine content in the vitreous body depends on the composition of the fly ash from the waste incineration, so periodic sampling is required to detect the fly ash and vitreous body components.

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