INTEGRATED PREPARATION AND DETECTION DEVICE FOR BIOMASS-BURNING AEROSOL AND METHOD THEREBY

Abstract

Disclosed herein are integrated preparation and detection devices for studying biomass-burning aerosols, where the devices include a micro-fluidized bed reactor (MFBR), a transmission line, and an on-line detection unit that are connected in sequence. The MFBR may include a pyrolysis reactor and a pyrolysis furnace; the pyrolysis reactor may include a thermocouple, an introduction tube, and quartz sands; the on-line detection unit may be an on-line photoionization mass spectrometer; and the photoionization mass spectrometer may include a laser desorption system, a laser ionizer and a light energy ionizer. Devices of the present disclosure are beneficial to retain the original state of aerosol particles, and the fixed MFBR can realize rapid pyrolysis of a biomass due to its high and stable heat conduction efficiency, which is beneficial to studying the formation mechanism of aerosol particles.

Claims

1. An integrated preparation and detection device for studying a biomass-burning aerosol, the device comprising a micro-fluidized bed reactor (MFBR), a transmission line, and an on-line detection unit that are connected in sequence.

2. The device according to claim 1, wherein: the micro-fluidized bed reactor (MFBR) comprises a pyrolysis reactor and a pyrolysis furnace; the pyrolysis reactor comprises a thermocouple, an introduction tube, and quartz sands; the on-line detection unit is an on-line photoionization mass spectrometer; and the photoionization mass spectrometer comprises a laser desorption system, a laser ionizer and a light energy ionizer.

3. The device according to claim 2, wherein the micro-fluidized bed reactor (MFBR) adopts a fixed design, and is filled with a specified number of quartz sands.

4. The device according to claim 2, wherein: the thermocouple is sealed by a fluorine rubber gasket when passing through a direct connection; and the quartz sands are located at a position 3 cm above the bottom of the reactor, with a thickness of 3 mm.

5. The device according to claim 1, wherein: the transmission line is externally provided with a relatively thick insulation layer and internally provided with a copper tube having an outer diameter of 3 mm for protecting capillary tubes; and the capillary tubes include a stainless steel ferrule and a graphite gasket for differential vacuum seal.

6. The device according to claim 2, wherein the photoionization mass spectrometer includes two laser sources to desorb and ionize an aerosol.

7. An aerosol preparation method using the integrated preparation and detection device according to claim 1, the method comprising: placing a biomass sample in an upper half of a pyrolysis reactor of the micro-fluidized bed reactor (MFBR), and then sealing the reactor and introducing nitrogen in order to remove oxygen from the reactor; and introducing the biomass into quartz sands within the pyrolysis reactor, thereby allowing the biomass to undergo pyrolysis due to a uniform temperature range of the quartz sands, to form an aerosol product.

8. An aerosol detection method using the integrated preparation and detection device according to claim 1, the method comprising: subjecting an aerosol product to size segregation, and then absorbing in the transmission line at 280° C.; transferring absorbed aerosol product into a photoionization mass spectrometer via the transmission line for on-line detection; and subjecting different aerosols to ionization and desorption with two kinds of laser according to characteristics of the aerosols.

9. The method according to claim 8, further comprising: processing detection results with acquisition software.

10. A method for detecting a macromolecular aerosol with the integrated preparation and detection device according to claim 1, the method comprising: subjecting the macromolecular aerosol first to desorption with a 1,064 nm laser and then to ionization with a 10.6 eV vacuum ultraviolet light, to obtain generated ions; and subjecting the generated ions to time-of-flight mass spectrometry (TOFMS).

11. An aerosol preparation method using the integrated preparation and detection device according to claim 2, the method comprising: placing a biomass sample in an upper half of the pyrolysis reactor, and then sealing the reactor and introducing nitrogen in order to remove oxygen from the reactor; and introducing the biomass into the quartz sands of the pyrolysis reactor, thereby allowing the biomass to undergo pyrolysis due to a uniform temperature range of the quartz sands, to form an aerosol product.

12. An aerosol detection method using the integrated preparation and detection device according to claim 2, the method comprising: subjecting an aerosol product to size segregation, and then absorbing in the transmission line at 280° C.; transferring absorbed aerosol product into the photoionization mass spectrometer via the transmission line for on-line detection; and subjecting different aerosols to ionization and desorption with two kinds of laser according to characteristics of the aerosols.

13. The method according to claim 12, further comprising: processing detection results with acquisition software.

14. A method for detecting a macromolecular aerosol with the integrated preparation and detection device according to claim 2, the method comprising: subjecting the macromolecular aerosol first to desorption with a 1,064 nm laser and then to ionization with a 10.6 eV vacuum ultraviolet light, to obtain generated ions; and subjecting the generated ions to time-of-flight mass spectrometry (TOFMS).

Description

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a schematic diagram illustrating the connection of an FBR and a photoionization mass spectrometer;

[0027] FIG. 2 is a schematic diagram of FBR;

[0028] FIG. 3 is a schematic diagram of a photoionization mass spectrometer;

[0029] FIG. 4 is a flow diagram of an experimental device; and

[0030] FIG. 5 is a mass spectrum of a product.

[0031] Reference numerals: 1 represents a fixed MFBR, 2 represents a transmission line, 3 represents an on-line detection unit, 101 represents a pyrolysis reactor, 102 represents a first thermocouple, 103 represents an introduction tube, 104 represents a first carrier gas-introducing tube, 105 represents a biomass-introducing device, 106 represents a pyrolysis furnace heating wire, 107 represents quartz sands, 108 represents a second carrier gas-introducing tube, 109 represents a second thermocouple, 301 represents a first vacuum pump, 302 represents a second vacuum pump, 303 represents a third vacuum pump, 304 represents an aerosol inlet, 305 represents a first laser transmitter, 306 represents a second laser transmitter, and 307 represents a third laser transmitter.

DETAILED DESCRIPTION

[0032] The disclosure is further described below through examples with reference to the accompanying drawings.

[0033] As shown in FIG. 1, a device for preparing and detecting an aerosol product from biomass combustion includes a fixed MFBR 1, a transmission line 2, and an on-line detection unit 3 that are connected in sequence.

[0034] As shown in FIG. 2 and FIG. 4, the fixed MFBR 1 adopts a fixed design; and a first thermocouple 102 and a second thermocouple 109 are placed in the FBR to detect the biomass reaction temperature in real time.

[0035] The fixed MFBR 1 includes a pyrolysis reactor 101 and a pyrolysis furnace; the pyrolysis reactor 101 includes a first thermocouple 102, an introduction tube 103, and quartz sands 107; the on-line detection unit 3 is an on-line photoionization mass spectrometer; and the photoionization mass spectrometer includes a laser desorption system, a laser ionizer and a light energy ionizer.

[0036] The fixed MFBR 1 adopts a fixed design and is made of quartz glass. A specified number of quartz sands 107 are placed in the fixed MFBR 1. Before experiment, a biomass-introducing device 105 is placed in the upper half of the pyrolysis reactor 101, and the reactor is sealed and introduced with nitrogen to remove air; the biomass is introduced into the quartz sands 107 and then undergoes pyrolysis due to a uniform temperature range of the quartz sands 107 to give an aerosol; and the aerosol is then introduced into the on-line photoionization mass spectrometer via the transmission line 2 for detection.

[0037] The first thermocouple 102 is sealed by a fluorine rubber gasket when passing through a direct connection; and the quartz sands 107 are located at a position 3 cm above the bottom of the pyrolysis reactor 101, with a thickness of 3 cm.

[0038] Housings of the pyrolysis furnace are all made of quartz glass.

[0039] The transmission line 2 is externally provided with a relatively thick insulation layer and internally provided with a copper tube having an outer diameter of 3 mm for protecting capillary tubes from being broken. The capillary tubes are sealed with a stainless steel ferrule and a graphite gasket, which are easy to be replaced.

[0040] The photoionization mass spectrometer uses two laser sources to desorb and ionize aerosols, where, a macromolecular aerosol is subjected first to desorption with 1,064 nm laser and then to ionization with 10.6 eV vacuum ultraviolet light; and generated ions are subjected to TOFMS.

[0041] As shown in FIG. 3, a new laser desorption system is added to the photoionization mass spectrometer. In the presence of a second laser transmitter 306 of a laser beam, a third laser transmitter 307 of a 1,064 nm laser beam is added to desorb aerosols in different states. In the photoionization mass spectrometer, 301, 302, and 303 are all vacuum pump extraction ports, and an aerosol inlet 304 is connected to the transmission line 2. An aerosol is transferred to the photoionization mass spectrometer after being subjected to size segregation. The aerosols in two states are subjected to desorption under different types of ionization energies, respectively, which is beneficial to analyze and detect aerosols in different states.

[0042] As shown in FIG. 4, the fixed MFBR 1 is connected to the photoionization mass spectrometer 3 via the transmission line 2, and a biomass is placed in the pyrolysis reactor 101. Generally, a biomass is fixed on the biomass-introducing device 105 by wire-winding, and then introduced into the quartz sands 107 for pyrolysis; nitrogen is introduced into the reactor through the first carrier gas-introducing tube 104 and the second carrier gas-introducing tube 108; the biomass begins to undergo combustion or pyrolysis after being heated to a certain temperature; an aerosol generated during the pyrolysis process flows into the transmission line 2 with the flow of carrier gas through the introduction tube 103, where, the transmission line 2 is connected to the aerosol inlet 304 on the mass spectrometer; the aerosol is subjected to size segregation in the photoionization mass spectrometer; and resulting two types of aerosols are subjected to ionization and desorption with two kinds of laser, respectively.

[0043] Description of Working Principles

[0044] A special case is adopted for illustration. Some elm (a biomass raw material) is taken and processed into cylinders with a diameter of 6 mm and a length of 15 mm for use. A specified number of quartz sands 107 are placed in the pyrolysis reactor 101. A temperature controller is first turned on for preheating (a preheating temperature is determined according to requirements of the pyrolysis). The preheating temperature is set to 500° C. While preheating, nitrogen is introduced into the MFBR at a certain flow rate (which is intended to blow off the remaining air in the reactor). When the temperature is stabilized at 500° C. and relatively uniform, the flow rate of nitrogen is adjusted to the required flow rate of a carrier gas. The prepared elm biomass is wound on the biomass-introducing device 105 with wires, and then introduced into the quartz sands 107 for pyrolysis. An aerosol generated from pyrolysis is introduced into the on-line detection unit 3 via the heated transmission line 2 for on-line detection. In the experiment, the pyrolysis temperature in the pyrolysis reactor 101 can be changed by adjusting the temperature controller, which is beneficial to study aerosols generated during the pyrolysis of a biomass at different temperatures. If an aerosol of a secondary pyrolysis product generated during a biomass combustion process needs to be detected, the introduced nitrogen can be changed into oxygen or air, and then a sample is re-added for detection.