Below with reference to the accompanying drawings, through the description of the embodiments, the specific embodiments of the present invention will be described in further detail, the purpose is to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and contribute to its implementation. It should be noted that the orientation or positional relationship indicated by the terms "up", "down", "front", "rear", "left", "right", "vertical", "inside", "outside", etc. Based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood to limit the invention.
 like figure 1 As shown, a forecasting system for sulfur dioxide in flue gas of a heating furnace includes a heating furnace 1 and a nozzle 2 provided on the heating furnace. The heating furnace 1 is connected to a chimney 14 through a flue gas main pipe 13. Air is sent to the air pipeline delivery mechanism in the nozzle 2, the gas pipeline delivery mechanism for delivering gas to the nozzle 2, and the gas detection and analysis mechanism for detecting and analyzing the gas composition in the gas delivery mechanism. By detecting H in gas 2 The content of S, and then the SO in the flue gas can be calculated 2 Real-time emission values.
 The gas pipeline conveying mechanism includes a gas main pipe 5 and a gas branch pipe 3. The gas main pipe 5 is connected to the nozzle 2 through the gas branch pipe 3. The gas detection and analysis mechanism includes a gas analyzer 11 and a gas detection module arranged in the gas main pipe 5. The gas analyzer 11 Connect with the gas detection module through the data cable. The gas detection module preferably adopts the laser emitting and receiving unit 9, and adopts the principle of laser method analysis, that is, the concentration of the gas is obtained by analyzing the selective absorption of the laser light by the gas.
 The gas main pipe 5 is provided with a gas thermometer 10 for testing the gas temperature. The insertion depth of the gas thermometer 10 is 1/3 of the diameter of the gas main pipe 5, or the insertion depth is 100 mm.
 The air pipeline conveying mechanism includes an air main pipe 6 , an air branch pipe 4 and a blower 7 arranged at the air inlet of the air main pipe 6 . The air outlet of the air main pipe 6 is connected to the nozzle 2 through the air branch pipe 4 . A hygrometer is installed at the air inlet of the blower to detect the humidity of the air sucked by the blower.
 In order to facilitate real-time calculation, the above-mentioned system further includes a data acquisition and processing unit, and the data acquisition and processing unit is connected with the gas analyzer through a data line.
 Specifically, each component module and its function in the forecast system of the present invention are as follows:
 Heating furnace: use gas to heat the materials in the furnace, and at the same time ensure that the gas is completely burned, and the sulfide in the gas is fully burned and oxidized, and SO is completely generated. 2. The heating furnace is mainly composed of a furnace body, an air supply system (air gas), a combustion system (a number of air gas burners are arranged in the furnace), and a smoke exhaust system.
 Burner: The gas and air sent through the gas branch pipe and the air branch pipe are mixed here in proportion, and sent to the combustion reactor for combustion to heat the material.
Gas branch pipe: The gas delivered by the gas main pipe is sent to the burner through it.
 Air branch pipe: The air delivered by the air main pipe is fed into the burner through it.
 Gas main: the gas from the gas source is sent to the burner through it.
 Blower: Combustion-supporting air power source, the ambient air is pressurized and sent into the air main.
 Hygrometer: It is arranged near the air inlet of the blower, detects the humidity of the air sucked by the blower online, and transmits the data to the data acquisition and processing system (unit).
 Laser transmitting and receiving unit: It is arranged on the gas main pipe in the way of opening and passing through. The laser passes through the gas from the transmitting end and is received by the receiving end. Each group has a pair of test holes.
 Gas thermometer: perform real-time processing and analysis on the spectral data from the laser transmitter and receiver unit, and obtain the gas composition (O 2 , CO, H 2 , CH 4 , CO, H 2 S), and transmit the data to the data acquisition and processing system (unit).
 Data acquisition and processing system (unit): real-time acquisition of detection data from gas analyzers, etc., and calculation of SO in flue gas through software model calculation 2 Real-time emission values.
 Flue gas main pipe: The flue gas generated by the combustion in the heating furnace is collected and transported to the chimney.
 Chimney: Use the temperature difference (height) to generate a pulling force to guide the exhaust of the flue gas, and to monitor the environmental protection at the points.
 The connection relationship of the above components is as follows:
 The gas delivered by the gas main pipe 5 is sent to the burner 2 through the gas branch pipe 3, and the air delivered by the blower 7 and the air main pipe 6 is sent to the burner 2 through the air branch pipe 4. The air and gas are mixed at the burner 2 and then sent to the burner 2. It enters the heating furnace 1 for combustion, and the generated flue gas is sent to the chimney 14 through the flue gas main pipe 13 for external discharge.
 The laser transmitting and receiving unit 9 is installed on the gas main pipe 5 by arranging the holes in the opposite direction. The laser transmitting and receiving unit 9 is connected with the gas analyzer 11 through a data line; the gas analyzer 11 is connected with the data acquisition and processing unit 12 through a data line. . A gas thermometer 10 is inserted into the gas main 5, and the gas thermometer 10 is connected to the data acquisition and processing unit 12 through a data cable.
 The forecasting method of the sulfur dioxide forecasting system in the flue gas of the heating furnace is to detect the dry gas composition through a gas analyzer, and obtain the theoretical flue gas volume of complete combustion through the calculation of the combustion reaction balance. 2 The detection of S, the calculation of SO in the flue gas 2 Real-time emission values, compared with emission limits for forecasting.
 The following is a description of a specific test example:
 Gas composition measured by gas analyzer:
 Calculate CmHn=0.0864×CH according to the empirical formula 4 = 0.0864 × 11.34 = 0.98%,
 Gas water content H 2 O s : The gas thermometer shows that the gas temperature is 30.6°C, and the water content of the gas is 4.30% in the saturated state of this temperature.
 The moisture content gk of dry air is 21.83g/Nm3, which is calculated when the hygrometer shows that the dry bulb is 30.6°C and the relative humidity is 62.4%.
 The relevant combustion material balance calculation model:
 Theoretical dry air volume L0g=0.0238 (H 2 s +CO s )+0.0952*CH 4 s +0.0476×3×CmHn s -0.0476×O 2 s
 Theoretical flue gas volume V0=0.01 (CO s +3CH 4 s +3CmHn s +CO 2 s +H 2 s +N 2 s +H 2 O s )+0.79×L0g
 Theoretical wet flue gas volume V0s=V0+0.00124gk×L0g
 Theoretical wet flue gas water content H 2 O 、s =0.01((2CH 4 s +H 2 s +CmHn s +H 2 O s )+0.00124×gk×L0g)/V0s×100
 Substitute into the calculation
 That is, under the theoretical combustion state (when the flue gas produced by combustion contains no combustible gas and the oxygen content is 0), each Nm 3 Wet gas actually produces 2.944Nm 3 Wet flue gas, the water content in flue gas is 20.55%.
 SO in flue gas 2 Numerical calculation of emissions:
 Suppose: H in gas 2 The total sulfur content of S accounts for 90% of the total sulfur content in the dry gas,
 H in some gas 2 The measured value of S is 98mg/Nm 3 , the total sulfur in the dry gas is H 2 S is calculated as 109mg/Nm 3;
 Then the H in the wet gas 2 S s =109×(100-4.30)÷100=104.3mg/Nm 3 (equivalent to 69ppm),
 Then the theoretical SO in wet flue gas 2 =H 2 S s /V0s=23ppm (equivalent to 67mg/Nm 3 ),
 Design: Relevant emission standard regulations: SO 2 The emission concentration is calculated in dry flue gas with an oxygen content of 8%.
 Then: SO 2 (mg/Nm 3 ) emission concentration = SO 2 (mg/Nm 3 )×(21-8)÷21÷(100-Theoretical wet flue gas water content H 2 O 、s )×100=52mg/Nm 3.
 Set relevant emission standards to stipulate SO 2 The emission concentration limit is less than 50mg/Nm 3 , the actual SO tested so far 2 The emission concentration is 52mg/Nm 3 , exceeding the standard alarm.
 To satisfy SO 2 The emission concentration limit is less than 50mg/Nm 3 requirements, the H in the dry gas 2 The measured value of S should be less than 93mg/Nm 3.
 The present invention has been exemplarily described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above manner. As long as the method concept and technical solution of the present invention are adopted for various non-substantial improvements; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention. within.