CN113513923A - A dual-process electric furnace waste heat utilization system with stable steam parameters - Google Patents
A dual-process electric furnace waste heat utilization system with stable steam parameters Download PDFInfo
- Publication number
- CN113513923A CN113513923A CN202110891761.0A CN202110891761A CN113513923A CN 113513923 A CN113513923 A CN 113513923A CN 202110891761 A CN202110891761 A CN 202110891761A CN 113513923 A CN113513923 A CN 113513923A
- Authority
- CN
- China
- Prior art keywords
- conduction oil
- heat conduction
- steam
- heat
- waste heat
- 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
Links
- 239000002918 waste heat Substances 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title abstract description 6
- 239000003546 flue gas Substances 0.000 claims abstract description 28
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000011084 recovery Methods 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000012530 fluid Substances 0.000 abstract description 4
- 239000000428 dust Substances 0.000 description 7
- 238000010248 power generation Methods 0.000 description 6
- 229920006395 saturated elastomer Polymers 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 5
- 230000008020 evaporation Effects 0.000 description 5
- 238000009834 vaporization Methods 0.000 description 4
- 230000008016 vaporization Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/10—Arrangements for using waste heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
- F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G1/00—Steam superheating characterised by heating method
- F22G1/02—Steam superheating characterised by heating method with heat supply by hot flue gases from the furnace of the steam boiler
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engine Equipment That Uses Special Cycles (AREA)
Abstract
本发明公开了一种蒸汽参数稳定的双流程电炉余热利用系统，包括导热油工质流程和蒸汽工质流程，所述的导热油工质流程包括依次连接的导热油烟道、导热油炉顶以及设置于导热油烟道、导热油炉顶上部的导热油储罐，导热油烟道、导热油炉顶和导热油储罐通过导热油管依次连接实现导热油在三个结构中循环；所述的蒸汽工质流程包括通过蒸汽管道依次连接的余热锅炉、蓄热器和过热器，所述的过热器置于所述导热油储罐内部；所述导热油工质流程的导热油烟道、导热油炉顶，以及蒸汽工质流程的余热锅炉依次连接形成余热回收的高温烟气流通通道。本发明为一种不借助外部能源即可使进入汽机的蒸汽参数稳定的双流程电炉余热利用系统。
The invention discloses a dual-flow electric furnace waste heat utilization system with stable steam parameters, comprising a heat-conducting oil working fluid flow and a steam working fluid flow. The heat transfer oil storage tank is arranged on the heat transfer oil flue and the top of the heat transfer oil furnace. The mass flow process includes a waste heat boiler, a heat accumulator and a superheater connected in sequence through a steam pipeline, and the superheater is placed inside the heat conduction oil storage tank; the heat conduction oil flue and the heat conduction oil furnace roof of the heat conduction oil working medium flow , and the waste heat boiler of the steam working fluid process are sequentially connected to form a high temperature flue gas circulation channel for waste heat recovery. The invention is a dual-flow electric furnace waste heat utilization system which can stabilize the parameters of the steam entering the steam turbine without the aid of an external energy source.
Description
Technical Field
The invention relates to the technical field of waste heat recovery devices, in particular to a waste heat utilization system of a double-flow electric furnace with stable steam parameters.
Background
The electric furnace waste heat utilization system passing in the market is limited by the smelting characteristics of the electric furnace, only saturated steam can be produced, and only low-pressure saturated steam of 0.8-1.0 MpaG can be provided to the steam inlet end of the steam turbine, and the actually-operated flue gas temperature and the flue gas amount are periodically fluctuated, so that the steam inlet parameters of the steam turbine are difficult to stabilize, and the power generation efficiency is low. And because the first two heat exchangers of the common electric furnace waste heat utilization system are the evaporation flue and the evaporation top cover, forced circulation is adopted, and a circulating pump needs to be matched, the structure has the hidden danger of pipe explosion on the heating surface. In the other electric furnace waste heat utilization system capable of improving the efficiency of the steam turbine in the prior art, a mode of electric furnace waste heat and a superheater is adopted, superheated steam needs to be provided for the steam turbine by means of external energy, and the actual operation efficiency of the waste heat recovery system is low.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the waste heat utilization system of the double-flow electric furnace, which can stabilize the parameters of steam entering a steam turbine without the help of external energy.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the waste heat utilization system comprises a heat conduction oil working medium flow and a steam working medium flow, wherein the heat conduction oil working medium flow comprises a heat conduction oil flue, a heat conduction oil furnace top and a heat conduction oil storage tank arranged on the upper parts of the heat conduction oil flue and the heat conduction oil furnace top which are sequentially connected, and the heat conduction oil flue, the heat conduction oil furnace top and the heat conduction oil storage tank are sequentially connected through heat conduction oil pipes to realize circulation of heat conduction oil in three structures; the steam working medium flow comprises a waste heat boiler, a heat accumulator and a superheater which are sequentially connected through a steam pipeline, wherein the superheater is arranged in the heat conduction oil storage tank; the heat conducting oil flue, the heat conducting oil furnace top and the waste heat boiler of the steam working medium flow are sequentially connected to form a high-temperature flue gas circulation channel for waste heat recovery.
Furthermore, the flow of the heat conduction oil working medium also comprises a circulating pump, wherein the circulating pump is arranged on a heat conduction oil pipe between the heat conduction oil storage tank and the heat conduction oil furnace top and drives the heat conduction oil to circulate in the heat conduction oil flue, the heat conduction oil furnace top and the heat conduction oil storage tank.
Furthermore, steam in the steam working medium flow is led to the steam turbine through a steam pipeline after the tail end of the steam working medium flow passes through the superheater.
Furthermore, a settling chamber is arranged between the top of the heat transfer oil furnace and the waste heat boiler in the high-temperature flue gas circulation channel, and the settling chamber is an electric furnace steelmaking waste heat and dust removal device and is beneficial to primary dust removal of flue gas discharged in an electric furnace.
Furthermore, a multi-stage heating surface is arranged in the waste heat boiler, a flue gas outlet is formed in the gas outlet end of the waste heat boiler, and the flue gas is discharged to a dust remover or other lower-level processing equipment through the flue gas outlet.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, after the first two heat exchangers of the electric furnace waste heat utilization system in the prior art are replaced by the heat conduction oil working medium flow from the evaporation flue and the evaporation top cover, because the heat conduction oil flow is forced to circulate originally, the heat conduction oil working medium flow is characterized by low pressure and high temperature originally, and evaporation is not generated, so that waste heat is absorbed, and the safety of the system is improved; after the flow is adopted, the steam amount is reduced, and the initial investment of the system is reduced; and the steam is superheated through the superheater arranged in the heat-conducting oil storage tank before being introduced into the steam turbine through the steam working medium flow, so that steam parameters are improved, the output of the generator is more stable, and the power generation efficiency can be greatly improved.
Drawings
FIG. 1 is a schematic view of the flue gas flow structure of the present invention;
FIG. 2 is a flow chart of working fluid of the present invention.
In the figure, 11-heat conducting oil flue, 12-heat conducting oil furnace top, 13-heat conducting oil storage tank, 14-circulating pump, 15-heat conducting oil pipe, 21-waste heat boiler, 211-heating surface, 212-flue gas outlet, 22-heat accumulator, 23-superheater, 24-steam pipeline, 3-settling chamber, and 4-scrap steel channel.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 1 and 2, the waste heat utilization system of the double-flow electric furnace with stable steam parameters comprises a heat conduction oil working medium flow and a steam working medium flow, wherein the heat conduction oil working medium flow comprises a heat conduction oil flue 11, a heat conduction oil furnace top 12 and a heat conduction oil storage tank 13 which are arranged on the upper parts of the heat conduction oil flue 11 and the heat conduction oil furnace top 12, which are sequentially connected, and the heat conduction oil flue 11, the heat conduction oil furnace top 12 and the heat conduction oil storage tank 13 are sequentially connected through a heat conduction oil pipe 15 to realize circulation of heat conduction oil in three structures; the steam working medium flow comprises a waste heat boiler 21, a heat accumulator 22 and a superheater 23 which are sequentially connected through a steam pipeline 24, wherein the superheater 23 is arranged inside the heat conduction oil storage tank 13; the heat conducting oil flue 11, the heat conducting oil furnace top 12 and the waste heat boiler 21 of the steam working medium flow are sequentially connected to form a high-temperature flue gas circulation channel for waste heat recovery, high-temperature flue gas flowing out of the waste steel channel 4 sequentially passes through the heat conducting oil flue 11, the settling chamber 3 and the waste heat boiler 21 (a multistage heating surface 211) to a flue gas outlet 212 and then flows to a dust remover, in the process, the high-temperature flue gas firstly absorbs heat by the heat conducting oil section and then absorbs heat by the water section, and steam is generated after the water section absorbs heat and flows to the heat accumulator 22 for storage.
Further, the flow of the heat conduction oil working medium further comprises a circulating pump 14, wherein the circulating pump 14 is arranged on a heat conduction oil pipe 15 between the heat conduction oil storage tank 13 and the heat conduction oil furnace top 12 and drives the heat conduction oil to circulate in the heat conduction oil flue 11, the heat conduction oil furnace top 12 and the heat conduction oil storage tank 13. The heat conducting oil working medium flow path is provided with a high-level storage tank, heat is stored on one side, the volume expansion of the heat conducting oil flow path system is absorbed on the other side, and a superheater 23 formed by a superheater tube bundle is embedded in the heat conducting oil storage tank 13 and used for superheating steam. After low-pressure saturated steam (1.2MpaG) produced by the heat accumulator 22 in the steam working medium flow passes through the superheater 23 in the heat conduction oil storage tank 13, steam parameters are stably increased to 1.0MpaG/300 ℃, so that the power generation efficiency is greatly improved.
Furthermore, the steam in the steam working medium flow path is led to the steam turbine through a steam pipeline 24 after the end passes through the superheater 23.
Furthermore, in the high-temperature flue gas circulation channel, a settling chamber 3 is arranged between the heat transfer oil furnace top 12 and the waste heat boiler 21, and the settling chamber 3 is an electric furnace steelmaking waste heat and dust removal device, and is beneficial to primary dust removal of flue gas discharged in an electric furnace.
Furthermore, the waste heat boiler 21 is internally provided with a multi-stage heating surface 211, the gas outlet end of the waste heat boiler 21 is provided with a flue gas outlet 212, and the flue gas is discharged to a dust remover or other lower-stage processing equipment through the flue gas outlet 212.
In the prior art, the first two heat exchangers of the electric furnace waste heat utilization system are a vaporization flue and a vaporization top cover, forced circulation is adopted, a circulating pump 14 needs to be matched, and the hidden danger of pipe explosion of a heating surface 211 still exists after the first two heat exchangers are changed. After the two sections are replaced by the heat conduction oil working medium flow, because the heat conduction oil flow is forced to circulate originally, the heat conduction oil flow is characterized by low pressure and high temperature originally, and the heat conduction oil flow can not generate vaporization, thereby absorbing the waste heat and improving the safety of the system; after the flow is adopted, the steam amount is reduced, and the initial investment of the system is reduced; and because the steam parameters are improved, the output of the generator is more stable.
Generally, the steam consumption of the 1.0MpaG saturated steam inlet parameter straight condensing unit is about 7.7-7.8 kg/KW, and the steam consumption of the 1.0MpaG/300 ℃ steam inlet parameter straight condensing unit is 6.5 kg/KW. Taking a certain electric furnace waste heat utilization system as an example, the flue gas amount of the channel outlet of the scrap steel channel 4 is 22 kilo-square/h, the highest flue gas temperature is 980 ℃ and the lowest flue gas temperature is 450 ℃, according to the existing common full steam flow, 5t/h is generated at the top of the vaporization flue and the settling chamber 3, and 18t/h-1.0MpaG saturated steam is generated in the whole process. According to the steam consumption of 7.7kg/kw, the power generation is about 2.33 MW; if the heat conduction oil flow and the steam flow are adopted, the steam amount is 13t/h-1.0/300 ℃, and the generated energy is 2 MW; the generated energy is seen to be reduced on the surface, but the electric furnace waste heat and saturated steam power generation system has the defects of other systems, because the flue gas temperature and the flue gas amount are in periodic fluctuation, the actual generated energy can not reach the paper data, and the engineering examination of a large amount of power generation by adopting a simple steam flow is failed or lost, and after adopting a heat conduction oil flow, the steam inlet parameters of a steam turbine can be stabilized due to the high-temperature characteristic of the heat conduction oil, so that the examination risk of the project is basically reduced to 0, and the generator can be efficiently and stably output.
It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and any modifications made by those skilled in the art without departing from the spirit of the present invention will fall within the protection scope of the present invention.
Claims (5)
1. The waste heat utilization system of the double-flow electric furnace with stable steam parameters is characterized in that: the system comprises a heat conduction oil working medium flow and a steam working medium flow, wherein the heat conduction oil working medium flow comprises a heat conduction oil flue, a heat conduction oil furnace top and a heat conduction oil storage tank arranged on the upper parts of the heat conduction oil flue and the heat conduction oil furnace top which are sequentially connected, and the heat conduction oil flue, the heat conduction oil furnace top and the heat conduction oil storage tank are sequentially connected through a heat conduction oil pipe to realize circulation of heat conduction oil in three structures; the steam working medium flow comprises a waste heat boiler, a heat accumulator and a superheater which are sequentially connected through a steam pipeline, wherein the superheater is arranged in the heat conduction oil storage tank; the heat conducting oil flue, the heat conducting oil furnace top and the waste heat boiler of the steam working medium flow are sequentially connected to form a high-temperature flue gas circulation channel for waste heat recovery.
2. The steam parameter-stabilized double-flow electric furnace waste heat utilization system of claim 1, characterized in that: the heat conduction oil working medium flow also comprises a circulating pump, wherein the circulating pump is arranged on a heat conduction oil pipe between the heat conduction oil storage tank and the heat conduction oil furnace top and drives the heat conduction oil to circulate in the heat conduction oil flue, the heat conduction oil furnace top and the heat conduction oil storage tank.
3. The steam parameter-stabilized double-flow electric furnace waste heat utilization system of claim 1, characterized in that: and the steam in the steam working medium flow is introduced to the steam turbine through a steam pipeline after the tail end of the steam passes through the superheater.
4. The steam parameter-stabilized double-flow electric furnace waste heat utilization system of claim 1, characterized in that: and a settling chamber is arranged between the top of the heat transfer oil furnace and the waste heat boiler in the high-temperature flue gas circulation channel.
5. The steam parameter stable double-flow electric furnace waste heat utilization system according to claim 1 or 4, characterized in that: the waste heat boiler is internally provided with a multi-stage heating surface, and the exhaust end of the waste heat boiler is provided with a flue gas outlet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110891761.0A CN113513923A (en) | 2021-08-04 | 2021-08-04 | A dual-process electric furnace waste heat utilization system with stable steam parameters |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110891761.0A CN113513923A (en) | 2021-08-04 | 2021-08-04 | A dual-process electric furnace waste heat utilization system with stable steam parameters |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113513923A true CN113513923A (en) | 2021-10-19 |
Family
ID=78068965
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110891761.0A Pending CN113513923A (en) | 2021-08-04 | 2021-08-04 | A dual-process electric furnace waste heat utilization system with stable steam parameters |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113513923A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102937379A (en) * | 2012-11-16 | 2013-02-20 | 宁夏光合能源科技有限公司 | Method and device for recycling and storing ferroalloy furnace flue waste heat for generating power |
| CN108645226A (en) * | 2018-05-24 | 2018-10-12 | 北京京诚科林环保科技有限公司 | Electric furnace flue gas double-working-medium heat exchange composite circulation superheated steam system |
| CN208998057U (en) * | 2018-10-16 | 2019-06-18 | 中冶赛迪工程技术股份有限公司 | A steam heat storage superheating system |
| CN112460580A (en) * | 2020-12-14 | 2021-03-09 | 北京京诚科林环保科技有限公司 | Double-circulation heat-conducting oil steam superheating system |
| CN215984014U (en) * | 2021-08-04 | 2022-03-08 | 上海四方无锡锅炉工程有限公司 | Double-flow-process electric furnace waste heat utilization system with stable steam parameters |
-
2021
- 2021-08-04 CN CN202110891761.0A patent/CN113513923A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102937379A (en) * | 2012-11-16 | 2013-02-20 | 宁夏光合能源科技有限公司 | Method and device for recycling and storing ferroalloy furnace flue waste heat for generating power |
| CN108645226A (en) * | 2018-05-24 | 2018-10-12 | 北京京诚科林环保科技有限公司 | Electric furnace flue gas double-working-medium heat exchange composite circulation superheated steam system |
| CN208998057U (en) * | 2018-10-16 | 2019-06-18 | 中冶赛迪工程技术股份有限公司 | A steam heat storage superheating system |
| CN112460580A (en) * | 2020-12-14 | 2021-03-09 | 北京京诚科林环保科技有限公司 | Double-circulation heat-conducting oil steam superheating system |
| CN215984014U (en) * | 2021-08-04 | 2022-03-08 | 上海四方无锡锅炉工程有限公司 | Double-flow-process electric furnace waste heat utilization system with stable steam parameters |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108643980B (en) | Ultrahigh pressure cylinder and high and medium pressure cylinder both have secondary reheating unit of additional reheat level | |
| RU2532635C2 (en) | Electric energy accumulation by thermal accumulator and reverse electric energy production by thermodynamic cyclic process | |
| CN103806969B (en) | A supercritical CO2 working fluid cycle power generation system | |
| JP2011231765A (en) | Operation method of power plant system and power plant system | |
| CN110397481B (en) | Garbage incineration power generation device capable of improving main steam parameters | |
| TWI645104B (en) | Fossil fuel power plant | |
| KR20150138661A (en) | The Coolant Waste Heat Recovery of Coal Fired Power Plant and Control Method | |
| CN103353239A (en) | Improved lime kiln exhaust gas waste heat power generation system and power generation method thereof | |
| CN101892879A (en) | A thermal power plant waste heat power generation device using phase change cycle of working fluid | |
| CN110206606A (en) | A kind of dry coke quenching with filling heat generating system again | |
| CN103471084B (en) | Low-pressure hot-water smoke cooling system and method for avoiding low-temperature corrosion of air pre-heater | |
| CN110793018A (en) | A steam reheating system for domestic waste incineration waste heat boiler heated by saturated steam | |
| CN215984014U (en) | Double-flow-process electric furnace waste heat utilization system with stable steam parameters | |
| RU2524588C2 (en) | Power plant running on organic fuel with carbon dioxide separator and method of its operation | |
| CN111396154A (en) | Coal-fired power generation unit thermodynamic system with additional supercritical carbon dioxide circulation | |
| CN214198738U (en) | Flue gas waste heat recovery system of coal-fired power plant | |
| CN112696656A (en) | A high-efficiency supercritical carbon dioxide boiler with dual working medium | |
| CN113513923A (en) | A dual-process electric furnace waste heat utilization system with stable steam parameters | |
| CN104420902B (en) | Heat exchanger with reheating and condensing functions, heat cycle system and method thereof | |
| CN103353102B (en) | A kind of device with high temperature and high pressure gas heat exchange | |
| RU2631961C1 (en) | Method for operation of binary combined cycle power plant | |
| KR20170102988A (en) | Heat exchangers, energy recovery devices and vessels | |
| CN214307058U (en) | A high-efficiency supercritical carbon dioxide boiler with dual working medium | |
| RU2561780C2 (en) | Combined-cycle plant | |
| RU2561776C2 (en) | Combined-cycle plant |
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 |