CN109580297A - A kind of coke oven flue gas detection device and detection method - Google Patents

A kind of coke oven flue gas detection device and detection method Download PDF

Info

Publication number
CN109580297A
CN109580297A CN201810718042.7A CN201810718042A CN109580297A CN 109580297 A CN109580297 A CN 109580297A CN 201810718042 A CN201810718042 A CN 201810718042A CN 109580297 A CN109580297 A CN 109580297A
Authority
CN
China
Prior art keywords
gas
uniform
coke oven
flue gas
stable room
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201810718042.7A
Other languages
Chinese (zh)
Inventor
庞克亮
武吉
侯士斌
刘冬杰
王超
朱庆庙
陈立哲
蔡秋野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Angang Steel Co Ltd
Original Assignee
Angang Steel Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Angang Steel Co Ltd filed Critical Angang Steel Co Ltd
Priority to CN201810718042.7A priority Critical patent/CN109580297A/en
Publication of CN109580297A publication Critical patent/CN109580297A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • G01N1/2247Sampling from a flowing stream of gas
    • G01N1/2258Sampling from a flowing stream of gas in a stack or chimney
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004Gaseous mixtures, e.g. polluted air
    • G01N33/0009General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0011Sample conditioning
    • G01N33/0016Sample conditioning by regulating a physical variable, e.g. pressure or temperature

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Pathology (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Molecular Biology (AREA)
  • Biomedical Technology (AREA)
  • Combustion & Propulsion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Sampling And Sample Adjustment (AREA)

Abstract

The present invention discloses a kind of coke oven flue gas detection device and detection method, including coke oven regenerator, coke oven regenerator connects collection air pump by gas collecting tube, collect the other end and the uniform and stable room of gas of air pump, the uniform and stable room of gas is connected with the vacuum pump vacuumized and connects, and the uniform and stable room of gas also passes through piping connection with flue gas inspection device;Valve is respectively equipped between coke oven regenerator and gas collecting tube, collection air pump and the uniform and stable room of gas, the uniform and stable room of gas and the uniform and stable room of vacuum pump, gas and coke oven flue gas detection device.Stablize coke oven flue gas gas componant, improve coke oven flue gas measurement accuracy, realizes that the analysis of the multiple regenerative chamber flue gas emission situations of coke oven is compared or more time phase coke oven flue gas emission behaviours compare, improve the evaluation comparativity of coke oven flue gas detection.

Description

A kind of coke oven flue gas detection device and detection method
Technical field
The invention belongs to metallurgical coking production technical field, it is related to a kind of coke oven flue gas detection device and method.
Background technique
The fuel that coke-oven plant's coke oven uses irregularly switches over for coke-stove gas and blast furnace gas, in process of coking, meeting Release a large amount of sulfide, nitrogen oxides and flue dust etc..Stack gases after heating gas burning pass through chimney outlet atmosphere, Middle pollutant is mainly SO2, NOx, dust particle etc..
2012, China was put into effect " coking chemistry emission of industrial pollutants standard ", in the standard, clear stipulaties " from From on January 1st, 2015, the discharge amount of conventional coke oven nitrogen oxides in effluent is no more than 500mg/m3, the discharge of sulfur dioxide Amount is no more than 50mg/m3." new standard in coke oven flue gas nitrogen oxides and sulfur dioxide (SO2) emissions require it is stringenter, especially It is to be no more than 150mg/m in line city emission limit nitrogen oxides such as " going up north wide "3, sulfur dioxide is no more than 30mg/m3
Start to carry out the useless cigarette of coke oven for environmental requirement and to the social responsibility of environmental protection, government department and coke-oven plant The detection of nitrogen oxides and sulfur dioxide in gas, including use is various offline, whether the discharge of online equipment monitoring pollution objects is up to standard, But most of monitoring tapping equipment is installed at coke oven flue gas chimney, that is, flue gas finally collects emission point, by It is made of in coke oven more regenerative chamber gas-fireds, therefore this can not the practical flue gas emission situation of accurate evaluation coke oven.In addition, There is part invention device to carry out flue gas measurement at coke oven regenerator flue, as " transverse direction of coke oven burning waste gas is oxygen-containing for patent Amount detecting device (CN 201387423Y) ", " a kind of coke oven flue gas oxygen content and nitrous oxides concentration detection system (CN 205280438 U) ", the method (106932349 U of CN) of oven wall of coke oven carbonization chamber blowby " a kind of detect ", but coke-stove gas Periodically there is commutation in burning, the ignition temperature in quirk is caused to change, and nitrous oxides concentration is mainly in coke oven flue gas Thermal NO, as coke oven flue gas temperature change difference is more obvious, so either online still offline inspection is set Standby, final detected value is moment flue gas content, and the coke oven flue gas value detected will appear maximum value and minimum value, wherein most Before big value appears in ascending air commutation, before minimum value appears in down current commutation, if on-line monitoring equipment detection data Being depicted as two dimensional plot will appear the concussion distribution situation with wave crest and trough, as shown in Figure 1.
Coke oven flue gas discharge testing result and detection time and commutation cycle, there are much relations.Often appear in rising Airflow-reversing stage testing result is exceeded, but practical coke oven flue gas pollutant discharge amount is lower, the inspection of down current commutation phase It is up to standard to survey result, but practical coke oven flue gas pollutant emission is higher, can not accurately measure coke oven flue gas emission behaviour.
Summary of the invention
For the defect of currently available technology, it is an object of the invention to provide in a kind of stable measurement coke oven some cycles Flue gas emission situation system and detection method, and then preferably evaluate coke oven flue gas emission behaviour, stablize coke oven flue gas gas at Point, coke oven flue gas measurement accuracy is improved, the analysis of the realization multiple regenerative chamber flue gas emission situations of coke oven is compared or more times Stage coke oven flue gas emission behaviour directly compares, and eventually by technique adjustment or scrap build, reduces oven pollutants discharge, Realize coke oven flue gas qualified discharge.
Object of the present invention is to what is realized by following technical solution:
A kind of coke oven flue gas detection device, it is characterised in that: including coke oven regenerator, coke oven regenerator is connected by gas collecting tube Collection air pump is connect, the other end and the uniform and stable room of gas of air pump are collected, the uniform and stable room of gas is connected with the vacuum pump vacuumized and connects, The uniform and stable room of gas also passes through piping connection with flue gas inspection device;Coke oven regenerator and gas collecting tube, collection air pump and gas are equal It is respectively equipped between even equalization chamber, the uniform and stable room of gas and the uniform and stable room of vacuum pump, gas and coke oven flue gas detection device Valve.
The coke oven flue gas detection device is controlled by automatic electrical control system.
A kind of coke oven flue gas detection method, it is characterised in that: be completely in the beginning shape of closing in detection device and valve State successively opens valve, vacuum pump between vacuum pump and the uniform and stable room of gas first, uniformly steady to gas using aspiration pump Determine room to be vacuumized, until pressure index ξ reaches vacuum values;The uniform and stable room evacuated pressure value of gas 0.1KPa~ 1KPa, and then the valve between vacuum pump, vacuum pump and the uniform and stable room of gas is successively closed, further successively open collection air pump Valve, gas collecting tube series of valves, collection air pump between the uniform and stable room of gas, start to carry out scrubbing operations, utilize collection air pump Coke oven flue gas is evacuated to the uniform and stable interior of gas, until pressure index ξ reaches maximum pressure tolerance range value, maximum bears pressure Power successively closes valve between collection air pump and the uniform and stable room of gas, gas collecting tube series of valves in 1.0KPa~1000KPa, Repeat the uniform and stable room of gas to vacuumize, after charge operation, reaches maximum again to the uniform and stable chamber pressure index ξ of gas Pressure bearing value range opens the valve between flue gas inspection device and the uniform and stable room of gas, using flue gas inspection device into The measurement of row coke oven flue gas.
The pressure index ξ is calculated according to the following formula:
Wherein, inlet velocity υ0, exit velocity υ1, inlet temperature T0, outlet temperature T1, gas density ρ, flowing time t, R For ideal gas constant 8.314Jmol-1·K-1, Pe=standard atmospheric pressure, Vm, a, b be pilot process constant.
The coke oven flue gas detection method can be measured the flue gas in the single ventilation cycle of coke oven regenerator, Flue gas in the multiple ventilation cycles of coke oven regenerator can be measured, mainly pass through the valve and aspiration pump on collecting pipe It is controlled, whole process is automatically performed operation under automatic electrical control system effect.
Of the invention a kind of coke oven flue gas detection device and method, stablize coke oven flue gas gas componant, improve coke oven flue gas Measurement accuracy realizes that the analysis of the multiple regenerative chamber flue gas emission situations of coke oven is compared or more time phase coke oven flue gas are arranged To one's heart's content condition compares, and improves the evaluation comparativity of coke oven flue gas detection.
Detailed description of the invention
Fig. 1 coke oven flue gas detection device schematic diagram,
Fig. 2 coke oven flue gas detects electric automatic control flow chart.
Wherein, 1. coke oven regenerator;2. gas collecting tube series of valves;3. gas collecting tube;4. collecting air pump;5. collecting air pump and gas being equal Valve between even equalization chamber;6. the uniform and stable room of gas;7. the valve between vacuum pump and the uniform and stable room of gas;8 is electrical Control system;9. vacuum pump;10. flue gas inspection device;Valve between 11 flue gas inspection devices and the uniform and stable room of gas.
Specific embodiment
It is illustrated combined with specific embodiments below:
Embodiment 1
A kind of coke oven flue gas detection device is that connect with coke oven regenerator 1 includes: gas collecting tube series of valves 2, gas collecting tube 3, aspiration pump 4 collects the valve 5 between air pump and the uniform and stable room of gas, and the uniform and stable room 6 of gas, vacuum pump is uniform with gas Valve 7 between equalization chamber, automatic electrical control system 8, vacuum pump 9, flue gas inspection device 10, flue gas inspection device and gas Valve 11 between uniform and stable room.
The coke oven flue gas detection device is taken out the flue gas in coke oven regenerator by the collection air pump 4 that gas collecting tube 3 connects To the uniform and stable room 6 of gas, set up series of valves 2, gas collection separately on the gas collecting tube that connect by gas collecting tube 3 with coke oven regenerator 1 The other end of pump 4 is connect with the uniform and stable room 6 of gas, and the valve 5 being equipped between collection air pump and the uniform and stable room of gas;Gas Uniform and stable room 6 is connected with the vacuum pump 9 vacuumized, and the pipeline of connection is equipped between vacuum pump and the uniform and stable room of gas Valve 7 carries out the vacuum pumping of the uniform and stable room 6 of gas by vacuum pump 9;The uniform and stable room 6 of gas is gone back and flue gas inspection Device 10 is carried out by piping connection, and by the valve 11 between the flue gas inspection device on pipeline and the uniform and stable room of gas Control, package unit are automatically performed operation under the effect of automatic electrical control system 8, as shown in Figure 2.
A kind of coke oven flue gas detection method is characterized in that being completely in the beginning state of closing in equipment and valve, first according to The secondary valve 7 opened between vacuum pump and the uniform and stable room of gas, vacuum pump 9, using vacuum pump 9 to the uniform and stable room of gas 6 It is vacuumized, until pressure index ξ1Reach 0.5KPa, and then it is uniform and stable successively to close vacuum pump 9, vacuum pump and gas Valve 7 between room, further successively open collection air pump and the uniform and stable room of gas between valve 5, gas collecting tube series of valves 2, collect air pump 4, start to carry out scrubbing operations, coke oven flue gas is evacuated in the uniform and stable room 6 of gas using collection air pump 4.Until pressure Power index ξ2Reach 100KPa, successively the valve 5 between closing collection air pump and the uniform and stable room of gas, gas collecting tube series of valves 2, Repeat the uniform and stable room 6 of gas to vacuumize, after charge operation, to the uniform and stable 6 pressure index ξ of room of gas2Reach again 100KPa opens the valve 11 between flue gas inspection device and the uniform and stable room of gas, carries out coke using flue gas inspection device 10 Kiln gas measurement, electric control system control flow are as shown in Figure 2.Coke oven flue gas detection device is will be burnt by collection air pump 4 Flue gas in furnace regenerative chamber 1 is pumped into the uniform and stable room 6 of gas collection, is controlled, is realized within a certain period of time by automatic 1 valve of electricity Flue gas is riddled within the scope of the maximum pressure-bearing 1000KPa in the uniform and stable room 6 of gas.
The embodiment is measured to the flue gas in the single ventilation cycle of single coke oven regenerator 1.
Embodiment 2
A kind of coke oven flue gas detection device includes coke oven regenerator 1, gas collecting tube series of valves 2, gas collecting tube 3, aspiration pump 4, Collect the valve 5 between air pump and the uniform and stable room of gas, the uniform and stable room 6 of gas, between vacuum pump and the uniform and stable room of gas Valve 7, automatic electrical control system 8, vacuum pump 9, flue gas inspection device 10, flue gas inspection device and the uniform and stable room of gas Between valve 11.
The coke oven flue gas detection device is taken out the flue gas in coke oven regenerator by the collection air pump 4 that gas collecting tube 3 connects To the uniform and stable room 6 of gas, set up series of valves 2, gas collection separately on the gas collecting tube that connect by gas collecting tube 3 with coke oven regenerator 1 The other end of pump 4 is connect with the uniform and stable room 6 of gas, and the valve 5 being equipped between collection air pump and the uniform and stable room of gas;Gas Uniform and stable room 6 is connected with the vacuum pump 9 vacuumized, and the pipeline of connection is equipped between vacuum pump and the uniform and stable room of gas Valve 7 carries out the vacuum pumping of the uniform and stable room 6 of gas by vacuum pump 9;The uniform and stable room 6 of gas is gone back and flue gas inspection Device 10 is carried out by piping connection, and by the valve 11 between the flue gas inspection device on pipeline and the uniform and stable room of gas Control, package unit are automatically performed operation under the effect of automatic electrical control system 8, as shown in Figure 2.
A kind of coke oven flue gas detection method is characterized in that being completely in the beginning state of closing in equipment and valve, first according to The secondary valve 7 opened between vacuum pump and the uniform and stable room of gas, vacuum pump 9, using vacuum pump 9 to the uniform and stable room of gas 6 It is vacuumized, until pressure index ξ1Reach 0.1KPa, and then it is uniform and stable successively to close vacuum pump 9, vacuum pump and gas Valve 7 between room, further successively open collection air pump and the uniform and stable room of gas between valve 5, gas collecting tube series of valves 2, collect air pump 4, start to carry out scrubbing operations, coke oven flue gas is evacuated in the uniform and stable room 6 of gas using collection air pump 4.Until pressure Power index ξ2Reach 1000KPa, successively the valve 5 between closing collection air pump and the uniform and stable room of gas, gas collecting tube series of valves 2, repeat the uniform and stable room 6 of gas and vacuumize, after charge operation, to the uniform and stable 6 pressure index ξ of room of gas2It reaches again To 1000KPa, the valve 11 between flue gas inspection device and the uniform and stable room of gas is opened, is carried out using flue gas inspection device 10 Coke oven flue gas measurement, electric control system control flow are as shown in Figure 2.Coke oven flue gas detection device is will by collection air pump 4 Flue gas in coke oven regenerator 1 is pumped into the uniform and stable room 6 of gas collection, is controlled, is realized in certain time by automatic 1 valve of electricity It is interior to riddle flue gas within the scope of the maximum pressure-bearing 2MP in the uniform and stable room 6 of gas.
The embodiment is that the flue gas in two ventilation cycles to entire coke oven regenerator 1 is measured.

Claims (3)

1. a kind of coke oven flue gas detection device, it is characterised in that: including coke oven regenerator, coke oven regenerator is connected by gas collecting tube Collect air pump, collect the other end and the uniform and stable room of gas of air pump, the uniform and stable room of gas is connected with the vacuum pump vacuumized and connects, gas The uniform and stable room of body also passes through piping connection with flue gas inspection device;Coke oven regenerator and gas collecting tube, collection air pump and gas are uniform Valve is respectively equipped between equalization chamber, the uniform and stable room of gas and the uniform and stable room of vacuum pump, gas and coke oven flue gas detection device Door.
2. coke oven flue gas detection device according to claim 1, it is characterised in that: the coke oven flue gas detection device by Automatic electrical control system control.
3. a kind of detection method using coke oven flue gas detection device described in claim 1, it is characterised in that include the following steps: It is completely in the beginning state of closing in detection device and valve, is successively opened between vacuum pump and the uniform and stable room of gas first Valve, vacuum pump, the uniform and stable room of gas is vacuumized using aspiration pump, until pressure index ξ reaches vacuum values;Gas The uniform and stable room evacuated pressure value of body is in 0.1KPa~1KPa, and then it is uniformly steady successively to close vacuum pump, vacuum pump and gas Determine the valve between room, further successively open collection air pump and the uniform and stable room of gas between valve, gas collecting tube series of valves, Collect air pump, start to carry out scrubbing operations, coke oven flue gas is evacuated to the uniform and stable interior of gas using collection air pump, until pressure index ξ reaches maximum pressure tolerance range value, and maximum bears pressure in 1.0KPa~1000KPa, successively closes collection air pump and gas is equal Valve, gas collecting tube series of valves between even equalization chamber repeat the uniform and stable room of gas and vacuumize, after charge operation, to The uniform and stable chamber pressure index ξ of gas reaches maximum pressure tolerance range value again, opens flue gas inspection device and gas is uniform Valve between equalization chamber carries out coke oven flue gas measurement using flue gas inspection device.
The pressure index ξ is calculated according to the following formula:
Wherein, inlet velocity υ0, exit velocity υ1, inlet temperature T0, outlet temperature T1, gas density ρ, flowing time t, R be reason Think gas constant 8.314Jmol-1·K-1, Pe=standard atmospheric pressure, Vm, a, b be pilot process constant.
CN201810718042.7A 2018-07-03 2018-07-03 A kind of coke oven flue gas detection device and detection method Pending CN109580297A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810718042.7A CN109580297A (en) 2018-07-03 2018-07-03 A kind of coke oven flue gas detection device and detection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810718042.7A CN109580297A (en) 2018-07-03 2018-07-03 A kind of coke oven flue gas detection device and detection method

Publications (1)

Publication Number Publication Date
CN109580297A true CN109580297A (en) 2019-04-05

Family

ID=65919609

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810718042.7A Pending CN109580297A (en) 2018-07-03 2018-07-03 A kind of coke oven flue gas detection device and detection method

Country Status (1)

Country Link
CN (1) CN109580297A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113532965A (en) * 2021-06-28 2021-10-22 鞍钢集团北京研究院有限公司 Coking gas collection apparatus and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201207023Y (en) * 2008-05-16 2009-03-11 韩琼 On-line measurement system for boiler discharging flue gas field
CN101526495A (en) * 2009-04-07 2009-09-09 北京三博中自科技有限公司 Method for detecting transverse oxygen content of burnt gas of coke oven and realizing device thereof
CN102680285A (en) * 2012-06-01 2012-09-19 上海化工研究院 Gas on-line sampling and pretreatment method and equipment for intermittent circulating gas producing technology
CN208547520U (en) * 2018-07-03 2019-02-26 鞍钢股份有限公司 A kind of coke oven flue gas detection device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201207023Y (en) * 2008-05-16 2009-03-11 韩琼 On-line measurement system for boiler discharging flue gas field
CN101526495A (en) * 2009-04-07 2009-09-09 北京三博中自科技有限公司 Method for detecting transverse oxygen content of burnt gas of coke oven and realizing device thereof
CN102680285A (en) * 2012-06-01 2012-09-19 上海化工研究院 Gas on-line sampling and pretreatment method and equipment for intermittent circulating gas producing technology
CN208547520U (en) * 2018-07-03 2019-02-26 鞍钢股份有限公司 A kind of coke oven flue gas detection device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113532965A (en) * 2021-06-28 2021-10-22 鞍钢集团北京研究院有限公司 Coking gas collection apparatus and method
CN113532965B (en) * 2021-06-28 2024-06-14 鞍钢集团北京研究院有限公司 Coking gas collection apparatus and method

Similar Documents

Publication Publication Date Title
CN103148473B (en) Optimal operation method and system for utility boiler based on CO
CN105465822A (en) Boiler automatic control system and method
CN110003923A (en) It is a kind of for measuring the device and measurement method of coke burning in coke dry quenching furnace
CN102393403B (en) Device and method for detecting combustion characteristic of tail gas containing high-concentration CO
CN105547000A (en) Routing inspection type flue gas adjusting system and method of rolled steel based double-heat-accumulation type heating furnace
CN101858591A (en) Diagnosis and prevention system and method of high temperature corrosion state of boiler water cooled wall
CN101526495A (en) Method for detecting transverse oxygen content of burnt gas of coke oven and realizing device thereof
CN201387423Y (en) Transverse oxygen content detecting device of burnt gas in coke oven
CN204903507U (en) Water -cooling wall wall atmosphere supervision measurement system is switched on multitube way
CN106885876B (en) A kind of coke oven flue gas oxygen content and nitrous oxides concentration detection system and method
CN208547520U (en) A kind of coke oven flue gas detection device
CN109580297A (en) A kind of coke oven flue gas detection device and detection method
CN107167418A (en) A kind of boiler water-cooling wall high-temperature corrosion on-line monitoring method and monitoring system
CN201845003U (en) Self-correcting online analytical instrument for oxygen concentration of flue gas
CN210012810U (en) Device for measuring coke burning loss in dry quenching furnace
CN108489537A (en) A kind of heater for rolling steel pollutant emission automatic monitoring device
CN111650104A (en) Multichannel token type blowby analysis system and method for coke oven regenerator
CN109635464A (en) A kind of steel mill's sulfur content in gas flexible measurement method
CN208537256U (en) SO in a kind of coke oven flue gas2Content detection system
CN105506305B (en) Combustion control system for copper refining
CN205280438U (en) Coke oven flue gas oxygen content and nitrogen oxide concentration detection system
CN212059617U (en) Hydrocarbon removing device in smoke detection and monitoring process
CN205506795U (en) Exhaust pollution detection device
CN113419025A (en) Coke oven air excess coefficient real-time monitoring device and adjusting method
CN208238837U (en) A kind of industrial gas emission monitoring device based on LoRa

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination