A generation system for condensable particulate matter

Abstract

The present invention discloses a generation system for condensable particulate matter, which includes a flue gas generation device, a flue gas reaction device, a rapid condensation device and a tail gas treatment device; the flue gas generation device includes a nitrogen source, an oxygen source, other gas sources and a premixing furnace, and a humidity generator is arranged between the nitrogen source and the premixing furnace; the flue gas reaction device includes a reaction furnace, an acidic aerosol atomizer, an organic matter atomizer and a flue gas analyzer; the rapid condensation device includes a condensation tube and a CPM filter membrane; the gas sequentially passes through the premixing furnace, the reaction furnace, the atomizer, the condensation tube, the CPM filter membrane, and finally enters the tail gas treatment device; this system can adjust the flue gas composition in real time and monitor the change rules of each component of CPM, simulate the flue gas components and the rapid cooling process of a real coal-fired power plant, as well as the CPM formation process, and provide a simulation method for studying the physical and chemical changes occurring instantaneously during the flue gas cooling and analyzing the evolution rules of key components of CPM.

Description

Technical Field

[0001] The present invention relates to a flue gas pollutant generation system, and particularly to a condensable particulate matter generation system. Background Art

[0002] Condensable particulate matter (CPM) refers to a substance that is in a gaseous phase in the flue but will condense into liquid or solid particulate matter within a few seconds due to rapid cooling after leaving the chimney. Analyzed from the "source-sink" perspective, total particulate matter (TPM) is composed of filter particulate matter (FPM) and CPM. With the implementation of ultra-low emission standards in China, conventional pollutants such as SO 2 , NOx, NH 3 etc. have been well controlled. For example, the concentration of FPM in coal-fired power plants has been controlled at 5 mg / Nm 3 . However, due to the special gaseous state of CPM in the chimney, the control effect of ultra-low emission facilities on CPM is not ideal, resulting in an increased proportion of CPM in TPM.

[0003] CPM poses a great threat to human health and atmospheric environmental quality. On the one hand, the concentrations of ions such as SO 4 2- , NO 3 - and NH 4 + in the inorganic components of CPM are relatively high, contributing significantly to the water-soluble ion content in PM in the soot. In particular, the concentration of SO 2.5 4 2- accounts for about 63.09% - 89.75% of the total mass concentration of inorganic components and is the key and difficult point for controlling CPM. On the other hand, the organic components of CPM mainly come from the incomplete combustion of coal, accounting for about 50.69% - 67.30% of the total CPM. The organic components of CPM mainly include organic acids, alkanes, lipids, aromatics, and other complex organic compounds, and are very likely to be one of the main sources of PM 2.5 in the atmosphere. In particular, persistent organic pollutants (such as polycyclic aromatic hydrocarbons) can interact synergistically with fine particulate matter, exacerbating pollution to a certain extent.

[0004] ​There are existing methods for on-site monitoring of CPM in coal-fired power plants, but the results show that neither the CPM concentration nor its composition has a unified variation law; this indicates that the variation of CPM is easily affected by external disturbances. For example, differences in coal composition, purification devices, and condensation conditions will all have a certain impact on the formation of CPM. In addition, although there have been some studies on the conversion characteristics of flue gas components, there is still a lack of clear analysis of the relationship between flue gas components and CPM. Summary of the Invention

[0005] Object of the Invention: The present invention aims to provide a condensable particulate matter generation system that can adjust the flue gas components in real time and monitor the variation law of each component of CPM.

[0006] Technical Solution: The condensable particulate matter generation system described in the present invention includes a flue gas generation device, a flue gas reaction device, a rapid condensation device, and a tail gas treatment device, which are connected by pipelines; the flue gas generation device includes a nitrogen source, an oxygen source, other gas sources, and a premixing furnace, and a humidity generator is arranged between the nitrogen source and the premixing furnace; the flue gas reaction device includes a reaction furnace, an acidic aerosol atomizer, an organic matter atomizer, and a flue gas analyzer, and a dilute sulfuric acid micro-injection needle is connected to the acidic aerosol atomizer, and an organic matter micro-injection needle is connected to the organic matter atomizer; the rapid condensation device includes a condenser tube and a CPM filter membrane, and a low-temperature circulation box is connected to the condenser tube; the gas coming out of the gas source is mixed in the premixing furnace and then enters the reaction furnace for further mixing and reaction, and then sequentially enters the atomizer, the condenser tube, the CPM filter membrane, and finally enters the tail gas treatment device.

[0007] The flue gas generation device is used to co-mix and generate flue gas consistent with the main components of coal-fired flue gas. A humidity generator is arranged between the nitrogen source and the premixing furnace, and nitrogen brings water vapor into the mixed gas to control and adjust the water molecule content of the flue gas.

[0008] The number of other gas sources can be adjusted as needed. Preferably, the other gas sources include SO 2 , NO x and NH 3 .

[0009] The gas is preliminarily mixed and preheated in the premixing furnace, and the temperature is set at about 150°C.

[0010] Preferably, the temperature of the reaction furnace is 350 - 500°C.

[0011] The flue gas reaction device is used to generate special gaseous pollutants and ensure the full mixing and reaction of flue gas components. The special gaseous pollutants mainly quantitatively control the speed of dilute sulfuric acid and organic solvents entering the atomizer through a micro-injection device, and the atomizer is used to evaporate the solvent into gas to generate SO 3 / Sulfuric acid aerosol or persistent organic gaseous pollutants, quantitative control of SO 3 / Sulfuric acid aerosol and persistent organic gaseous pollution can meet the requirements for analyzing the key components of CPM. The flue gas analyzer can regulate the concentration of flue gas components in real time and quantitatively study single or multiple pollutants.

[0012] Preferably, the temperature of the acidic aerosol atomizer is not lower than 520 °C to generate SO 3 / Sulfuric acid aerosol.

[0013] The organic matter atomizer is used to stabilize the organic components into aerosol or gas state. The temperature should be lower than the decomposition temperature of the organic matter. Therefore, the temperature of the organic matter atomizer is not higher than 300 °C, and the preferred temperature range is 150 - 300 °C.

[0014] Preferably, the temperature of the atomizer is not lower than 520 °C.

[0015] The rapid condensation system is used to simulate the condensation process of flue gas after leaving the chimney. After the flue gas is introduced into the condensation tube, it condenses rapidly, and the CPM filter membrane captures the ultrafine particles generated during the rapid condensation process. Controlling the condensation temperature and humidity of the flue gas can provide a simulation method for studying the physical and chemical changes occurring during the instant cooling of the flue gas.

[0016] Preferably, the CPM filter membrane is a quartz membrane with a size of 0.1 - 2.5 μm, and the best is 0.22 μm.

[0017] Preferably, the temperature of the condensation tube is 5 - 75 °C.

[0018] The tail gas treatment system mainly includes a gas absorber and a silica gel dryer, which are used to fully purify the flue gas to meet the emission standards.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: (1) The system can adjust the flue gas composition in real time and monitor the change rules of each component of CPM, simulate the flue gas composition and rapid cooling process of a real coal-fired power plant, simulate the CPM formation process after the coal-fired flue gas is discharged into the atmosphere, provide a simulation method for studying the physical and chemical changes occurring during the instant cooling of the flue gas, and can also analyze the evolution rules of the key components of CPM; (2) This system quantitatively controls SO 3 / Sulfuric acid aerosol and persistent organic gaseous pollutants by injecting dilute sulfuric acid and organic solvents into the atomizer through a syringe needle to meet the requirements for analyzing the key components of CPM; (3) This system controls the condensation temperature and humidity of the flue gas to provide a simulation method for studying the physical and chemical changes occurring during the instant cooling of the flue gas; (4) This system is simple to operate, and the method for generating condensable particulate matter is simple and fast, with no special requirements for equipment; (5) This system has low energy consumption, low pollution and is environmentally friendly during use. Description of the Drawings

[0020] Figure 1 This is a schematic diagram of the system of the present invention. Specific embodiments

[0021] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0022] Embodiment 1

[0023] As Figure 1 shown, the system for generating condensable particulate matter of the present invention includes a flue gas generating device 1, a flue gas reaction device 2, a rapid condensation device 3, and a tail gas treatment device 4, and the devices are connected by pipelines; the flue gas generating device 1 includes a nitrogen source 11, an oxygen source 14, other gas sources 15, and a premixing furnace 13, a humidity generator 12 is arranged between the nitrogen source 11 and the premixing furnace 13, and the other gas sources 15 include O 2 , SO 2 , NO x , and NH 3 , and the gas source outlet is connected to a proton flowmeter 18; the flue gas reaction device 2 includes a reaction furnace 21, an acidic aerosol atomizer 23, an organic matter atomizer 24, and a flue gas analyzer 22, a dilute sulfuric acid micro-syringe 25 is connected to the acidic aerosol atomizer 23, and an organic solvent micro-syringe 26 is connected to the organic matter atomizer 24; the rapid condensation device 3 includes a condenser tube 31 and a CPM filter membrane 32, and a low-temperature circulation box 33 is connected to the condenser tube 31; the tail gas treatment device 4 includes a tail gas absorber 41, a flowmeter 42, a silica gel dryer 43, and a suction pump 44; the gas coming out of the gas source is mixed in the premixing furnace 13 and then enters the reaction furnace 21 for further mixing and reaction, and then enters the acidic aerosol atomizer 23 and the organic matter atomizer 24 respectively, then enters the condenser tube 31 and the CPM filter membrane 32, and finally enters the tail gas treatment device 4.

[0024] The usage method is as follows:

[0025] 1. Generation of condensable particulate matter

[0026] (1) In the early stage of the experiment, first introduce the background gases N 2 and O 2, run the entire device according to the set parameter values, etc., including the flue gas generation system 1, the flue gas reaction system 2, the rapid condensation system 3 and the tail gas treatment system 4. The temperature of the premixing furnace 13 is 150 °C to preliminarily mix the gases; the temperature of the reaction furnace 21 is 350 - 500 °C to ensure the full mixing and reaction of the flue gas; the temperature of the acidic aerosol atomizer is set at 520 °C to ensure that all components are in a gaseous or aerosol state; the temperature of the organic matter atomizer is 150 - 300 °C to stabilize the organic components into aerosols or gases, which can be adjusted according to the decomposition temperature of the organic components; the temperature of the condenser tube is set at 5 - 75 °C to ensure the full condensation of the flue gas.

[0027] (2) After the system is stable, gradually introduce gaseous pollutants such as SO 2 , NH 3 and NO x . Use the mass flowmeter 18 to accurately control the gas flow rate, and use the flue gas analyzer 22 to monitor the changes in flue gas composition in real time, in order to generate gases consistent with those of coal-fired power plant flue gas. Among them, the concentrations of SO 2 , NH 3 and NO x refer to the ultra-low emission standards for coal-fired boilers in thermal power plants implemented since 2014. In addition, use a micro-syringe for dilute sulfuric acid to uniformly introduce dilute sulfuric acid. After atomization by the acidic aerosol atomizer 23, SO 3 / sulfuric acid aerosol is obtained; use a micro-syringe for organic solvent to uniformly introduce the organic standard solvent. After heating by the organic matter atomizer 24, organic gaseous pollutants are obtained.

[0028] 2. Sampling

[0029] The sampling time is about 1.5 hours, and the sampling method is as follows:

[0030] (1) Sampling from the condenser tube

[0031] Rinse the condenser tube with 10 ml of ultrapure water and 10 ml of n-hexane, repeat 3 times, and collect the washing liquid; then extract the washing liquid with 20 ml of n-hexane. Each experiment is repeated three times to ensure reliable data, and finally n-hexane extract and ultrapure water extract are obtained.

[0032] (2) Sampling with a filter membrane

[0033] First, dry the filter membrane under vacuum to eliminate the error caused by interfacial water. Cut the membrane into fragments with a diameter of about 5 mm and extract CPM with 10 ml of ultrapure water through an ultrasonic water bath to obtain an ultrapure water extract; then, extract the organic components on the membrane with 10 ml of n-hexane to obtain an n-hexane extract.

[0034] Combine the ultrapure water extracts and n-hexane extracts from the condenser tube and the filter membrane respectively.

[0035] 3. Sample analysis

[0036] (1) Ion chromatography (IC) is used to test the inorganic substances in the ultra-pure water extract, so as to quantitatively analyze the inorganic components in CPM.

[0037] (2) A gas chromatography / mass spectrometer equipped with HP-5ms (30m * 250μm * 0.25μm) is used to test the organic substances in the n-hexane extract, so as to qualitatively analyze the organic components in CPM. Among them, the organic sample needs to be first evaporated and concentrated to 1 ml and then subjected to subsequent analysis.

Claims

1. A generation system for condensable particulate matter, characterized in that, it includes a flue gas generation device (1), a flue gas reaction device (2), a rapid condensation device (3) and a tail gas treatment device (4), and the devices are connected by pipelines; the flue gas generation device (1) includes a nitrogen source (11), an oxygen source (14), other gas sources (15) and a premixing furnace (13), and a humidity generator (12) is arranged between the nitrogen source (11) and the premixing furnace (13); the flue gas reaction device (2) includes a reaction furnace (21), an acidic aerosol atomizer (23), an organic matter atomizer (24) and a flue gas analyzer (22), a dilute sulfuric acid micro-injection needle (25) is connected to the acidic aerosol atomizer (23), and an organic solvent micro-injection needle (26) is connected to the organic matter atomizer (24); the rapid condensation device (3) includes a condenser tube (31) and a CPM filter membrane (32), and a low-temperature circulation box (33) is connected to the condenser tube (31); the gas coming out of the gas source is mixed in the premixing furnace (13), then enters the reaction furnace (21) for further mixing and reaction, and then enters the acidic aerosol atomizer (23) and the organic matter atomizer (24) respectively, then enters the condenser tube (31), the CPM filter membrane (32), and finally enters the tail gas treatment device; the temperature of the reaction furnace (21) is 350-500°C; the temperature of the condenser tube is 5-75°C.

2. The generation system for condensable particulate matter according to claim 1, characterized in that, the temperature of the acidic aerosol atomizer (23) is not lower than 520°C.

3. The generation system for condensable particulate matter according to claim 1, characterized in that, the temperature of the organic matter atomizer (24) is not higher than 300°C.

4. The generation system for condensable particulate matter according to claim 1, characterized in that, The other gas sources (15) include SO 2 , NO x and NH 3 .

5. The generation system for condensable particulate matter according to claim 1, characterized in that, the CPM filter membrane is a quartz membrane with a size of 0.1-2.5 μm.

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