CN107389740B - Online monitoring system for abrasion loss and corrosion loss of flue gas side of heating surface - Google Patents
Online monitoring system for abrasion loss and corrosion loss of flue gas side of heating surface Download PDFInfo
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- CN107389740B CN107389740B CN201710655904.1A CN201710655904A CN107389740B CN 107389740 B CN107389740 B CN 107389740B CN 201710655904 A CN201710655904 A CN 201710655904A CN 107389740 B CN107389740 B CN 107389740B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
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- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The invention provides an online monitoring system for the abrasion loss and corrosion loss of a flue gas side of a heating surface, which comprises a film-coated sensor, wherein the film-coated sensor consists of a planar carrier base, a lead and a film resistor made of the same material as the heating surface, the film resistor is uniformly arranged on the planar carrier base, the planar carrier base is fixed on the heating surface, and the film resistor is connected with a resistance measuring system through the lead. The system provided by the invention overcomes the defects in the prior art, combines the film-coated sensor with the high-temperature heating surface, adopts the high-precision data acquisition device to measure the resistance change of the mode sensor, and reversely pushes the resistance thickness change according to the relation between the resistance thickness and the resistance value, thereby obtaining the change of the abrasion loss and corrosion loss of the flue gas side of the heating surface; the system has the advantages of simple structure, low cost, convenient and accurate measurement, is beneficial to the safe and stable operation of the heating surface, and reduces the non-stop of the unit caused by the abrasion and corrosion of the heating surface.
Description
Technical Field
The invention relates to an online monitoring system for abrasion loss and corrosion loss of a flue gas side of a heating surface, and belongs to the technical field of calculation of the heating surface of a boiler.
Background
In a thermal power plant, the problem of high temperature corrosion of the heating surface of a boiler is an economic and technical problem which has long plagued the power plant. The high-temperature corrosion causes the wall of the heating surface to be thinned, and the pipe explosion can be caused when the pipe explosion is serious, so that the workload of temporary overhaul and overhaul of the power plant is greatly increased, and great economic loss is caused to the power plant. The unplanned outage time caused by the explosion of the heating surface of the boiler of the thermal power plant accounts for about 40% of the unplanned outage time of the unit, the small power generation amount accounts for more than 50% of the small power generation amount of all accidents, and the unplanned outage time is an important factor affecting the safe and economic operation of the generator unit, and meanwhile, the normal scheduling of the power grid system in the whole area is interfered, the local industrial and agricultural production is affected, and the caused social benefit loss is huge.
The existing method for monitoring the high-temperature corrosion of the heated surface generally comprises a flue gas sampling pipe, a flue gas analyzer, an industrial personal computer, a high-temperature thermocouple and a display, wherein 1-5 layers of measuring points are arranged along the height direction of a hearth by opening holes in a connecting plate between the pipes of a membrane water-cooled wall, flue gas is extracted through the flue gas sampling pipe, and CO and O in the flue gas are measured through the flue gas analyzer 2 And SO 2 And the three gas concentrations are combined with a high-temperature thermocouple to measure the wall temperature of the water-cooled wall surface, and measured data are transmitted to an industrial personal computer. Meanwhile, the industrial personal computer receives the data of the primary air speed, the secondary air speed and the air powder concentration in the Oracle database of the MIS system of the power plant, and utilizes an improved fuzzy analytic hierarchy process to analyze and process the data so as to calculate the current high-temperature corrosion influence factorsThe weight is small and large, real-time sorting is carried out according to the weight, the result is displayed on a display screen in a friendly way, and meanwhile, corresponding diagnosis comments are given, and operators are required to adjust in time. The method for monitoring the high-temperature corrosion of the heating surface can only slow down the corrosion, but cannot quantitatively display the thickness change of the heating surface due to the high-temperature corrosion, namely cannot monitor the corrosion amount change of the corrosion heating surface.
The boiler is subjected to the scouring of the flue gas for a long time in the running process, and the abrasion influence of fly ash particles in the flue gas on the heating surface is large, so that the frequent replacement of the heating surface is caused, the power generation cost is increased, and leakage or pipe explosion accidents of the heating surface are caused, so that the damage is large. Fly ash abrasion on heated surfaces is generally of a local nature, and is generally more severe in areas where the flue gas flow rate is high and the ash concentration is high, and the degree of abrasion is also uneven from the perspective of the circumference of the pipe being abraded. When the flue gas flushes the heating surface in the boiler flue, the phenomenon that fly ash particles with a certain quantity of kinetic energy impact the pipe wall often exists, and each impact can possibly cut off extremely tiny metal scraps from the pipe wall. Over time, the more and less the tube wall will be shaved due to the constant flushing of fly ash. The method for reducing the abrasion of the heating surface mainly comprises the steps of adding an abrasion-proof device, reducing the fly ash content in the flue gas and the like, and can reduce the abrasion of the heating surface to a certain extent. In the aspect of abrasion loss calculation, the evolution process of a related boiler heating surface abrasion loss calculation formula of the soviet union in the last 40 years is summarized and analyzed, a principle and a method for determining the heating surface abrasion performance coefficient value when the abrasion loss is calculated are further provided on the basis, a linear calculation chart for calculating the abrasion loss is drawn, a certain reference is provided for researching the problem of surface abrasion, and the problem of how to monitor the thinning amount caused by abrasion in the operation process of the heating surface is not solved.
In the aspect of preventing and controlling the low-temperature corrosion of the heating surface, there are methods of adding a warm air blower at the inlet of the air preheater, adopting a flue gas recirculation technology, adding a heating medium water system and the like, and the method can improve the temperature of the low-temperature heating surface, plays a certain role in slowing down the low-temperature corrosion of the heating surface, but cannot quantitatively monitor the low-temperature corrosion of the heating surface on line.
Disclosure of Invention
The invention aims to solve the technical problem of how to monitor the abrasion loss change and the temperature corrosion loss change of the flue gas side of the heating surface of the boiler of the thermal power plant on line.
In order to solve the technical problems, the technical scheme of the invention is to provide an on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface, which is characterized in that: the film-coated sensor comprises a planar carrier base, a lead and a film resistor made of the same material as the heating surface, wherein the film resistor is uniformly arranged on the planar carrier base, the planar carrier base is fixed on the heating surface, and the film resistor is connected with a resistance measurement system through a lead.
Preferably, the planar support base is an alumina ceramic wafer base.
Preferably, two ends of the thin film resistor are respectively connected with the resistance measurement system through a wire.
Preferably, the thin film resistor is uniformly processed on the planar carrier base through a magnetron sputtering process.
Preferably, when the length and the width of the film-coated sensor are unchanged, the resistance value is only in inverse proportion to the thickness; the change of the thickness of the film-coated sensor is deduced by monitoring the change of the resistance of the film-coated sensor, and further the change of the abrasion loss and corrosion loss of the heated surface is deduced.
Preferably, the relationship between the thickness of the thin film resistor and the resistance value thereof is:
wherein ρ is the resistivity of the thin film resistive material, L R Length of thin film resistor, W R The width of the thin film resistor is shown, and delta is the thickness of the thin film resistor; when the length and the width of the thin film resistor are unchanged, the resistance value is only in inverse proportion to the thickness;
the film resistor is gradually thinned by the scour and abrasion of flue gas in the furnace, the resistance change of the film resistor is measured, and the thickness change delta of the film resistor is obtained by back-pushing t The calculation formula is as follows:
wherein R is 0 R is the resistance value measured in the corrosion process for the measured initial resistance value of the thin film resistor;
the thickness change of the film resistor is the change of the abrasion loss and corrosion loss of the flue gas side of the heating surface.
The system provided by the invention overcomes the defects in the prior art, combines the film-coated sensor with the high-temperature heating surface, adopts the high-precision data acquisition device to measure the resistance change of the mode sensor, and reversely pushes the resistance thickness change according to the relation between the resistance thickness and the resistance value, thereby obtaining the change of the abrasion loss and corrosion loss of the flue gas side of the heating surface; the system has the advantages of simple structure, low cost, convenient and accurate measurement, is beneficial to the safe and stable operation of the heating surface, and reduces the non-stop of the unit caused by the abrasion and corrosion of the heating surface.
Drawings
Fig. 1 is a schematic diagram of an online monitoring system for the abrasion loss and corrosion loss of the flue gas side of the heating surface according to the embodiment.
Detailed Description
The invention will be further illustrated with reference to specific examples.
Fig. 1 is a schematic diagram of an online monitoring system for the abrasion loss and corrosion loss of the flue gas side of the heating surface, which is provided in this embodiment, and the online monitoring system for the abrasion loss and corrosion loss of the flue gas side of the heating surface includes a film-coated sensor, as shown in the flue gas side sensor portion in the furnace in fig. 1, where the film-coated sensor is composed of a planar carrier base, a sheet resistor and a lead. The thin film resistor is made of the same material as the heating surface. And uniformly processing the thin film resistor which is the same as the material of the heating surface on a plane carrier base by adopting a magnetron sputtering process, fixing the plane carrier base on the heating surface, and leading out the two ends of the thin film resistor through two leads to be connected with a data acquisition system.
When the length and the width of the film-coated sensor are unchanged, the resistance value is only in linear inverse proportion to the thickness, and the smaller the thickness is, the larger the resistance value is. The change of the thickness of the sensor is deduced by monitoring the change of the resistance of the film-coated sensor, and further the change of the abrasion loss and corrosion loss of the heated surface is deduced. The method comprises the following steps:
the relation between the thickness of the film resistor and the resistance value is as follows:
wherein ρ is the resistivity of the thin film resistor metal material, L R Length of thin film resistor, W R The width of the thin film resistor, and delta is the thickness of the thin film resistor. When the length and width of the film resistor are unchanged, the resistance value is only in inverse proportion to the thickness, and the smaller the thickness is, the larger the resistance value is.
In the embodiment, a layer of metal film which is the same as the material of the heating surface tube is uniformly plated on the surface of the aluminum oxide ceramic plate substrate by adopting a magnetron sputtering process. The length and width of the sheet resistor are fixed, and the resistor is only related to the thickness. The thin film resistor is used for replacing a heating surface, the thin film resistor material is subjected to the erosive wear of flue gas in the furnace in a period of time, the thin film resistor material is gradually thinned, and the change of the resistance is measured by adopting a high-precision data acquisition device, so that the change of the thickness of the thin film resistor material can be reversely deduced, and further the change of the wear and corrosion of the heating surface is judged. Variation delta of thin film resistive material thickness t The calculation formula of (2) is as follows:
wherein R is 0 For the measured initial resistance value of the sheet resistance, R is the resistance value measured during the etching process.
δ t Namely the change of the abrasion loss and corrosion loss of the heating surface.
In the invention, the film sensor at the flue gas side in the furnace and the data collector outside the furnace are combined together, so that the abrasion loss of the heated surface and the development degree of the temperature corrosion can be quantitatively monitored on line. The system overcomes the defect that the traditional device can only monitor the corrosion amount change in an online quantitative way by improving the temperature corrosion at the heated surface. The change of the high-temperature corrosion amount of the heating surface is monitored in real time on line, so that the safe and stable operation of the high-temperature heating surface is facilitated, and the non-stop of the unit caused by low-temperature corrosion is reduced.
While the invention has been described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and additions may be made without departing from the scope of the invention. Equivalent embodiments of the present invention will be apparent to those skilled in the art having the benefit of the teachings disclosed herein, when considered in the light of the foregoing disclosure, and without departing from the spirit and scope of the invention; meanwhile, any equivalent changes, modifications and evolution of the above embodiments according to the essential technology of the present invention still fall within the scope of the technical solution of the present invention.
Claims (6)
1. An on-line monitoring system for abrasion loss and corrosion loss of flue gas side of heating surface is characterized in that: the film-coated sensor comprises a planar carrier base, a lead and a film resistor made of the same material as the heating surface, wherein the film resistor is uniformly arranged on the planar carrier base, the planar carrier base is fixed on the heating surface, and the film resistor is connected with a resistance measurement system through a lead.
2. The on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface according to claim 1, wherein: the plane carrier base is an alumina ceramic wafer base.
3. The on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface according to claim 1, wherein: and two ends of the film resistor are respectively connected with the resistor measuring system through a wire.
4. The on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface according to claim 1, wherein: the thin film resistor is uniformly processed on the plane carrier base through a magnetron sputtering process.
5. The on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface according to claim 1, wherein: when the length and the width of the film-coated sensor are unchanged, the resistance value of the film-coated sensor is only in linear inverse proportion to the thickness; the change of the thickness of the film-coated sensor is deduced by monitoring the change of the resistance of the film-coated sensor, and further the change of the abrasion loss and corrosion loss of the heated surface is deduced.
6. An on-line monitoring system for the abrasion loss and corrosion loss of the flue gas side of a heating surface according to claim 1 or 5, wherein: the relation between the thickness of the thin film resistor and the resistance value is as follows:
wherein ρ is the resistivity of the thin film resistive material, L R Length of thin film resistor, W R The width of the thin film resistor is shown, and delta is the thickness of the thin film resistor; when the length and the width of the thin film resistor are unchanged, the resistance value is only in inverse proportion to the thickness;
the film resistor is gradually thinned by the scour and abrasion of flue gas in the furnace, the resistance change of the film resistor is measured, and the thickness change delta of the film resistor is obtained by back-pushing t The calculation formula is as follows:
wherein R is 0 R is the resistance value measured in the corrosion process for the measured initial resistance value of the thin film resistor;
the thickness change of the film resistor is the change of the abrasion loss and corrosion loss of the flue gas side of the heating surface.
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| CN201710655904.1A CN107389740B (en) | 2017-08-03 | 2017-08-03 | Online monitoring system for abrasion loss and corrosion loss of flue gas side of heating surface |
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| CN113566691A (en) * | 2021-06-28 | 2021-10-29 | 河钢股份有限公司 | Blast furnace tapping main channel online monitoring device and method |
| CN113720881A (en) * | 2021-08-23 | 2021-11-30 | 西安热工研究院有限公司 | On-line monitoring method for corrosion depth of boiler heating surface based on resistance measurement |
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| CN88102279A (en) * | 1988-04-18 | 1988-11-30 | 华东师范大学 | Aluminium titanium film resistor temperature sensor and preparation method |
| DE3918818A1 (en) * | 1989-06-09 | 1990-12-13 | Degussa | Pressure sensor with film resistance strain gauge - has ceramic plate with corrosion and abrasion resistant insulation cover plate |
| JP2007292747A (en) * | 2006-03-29 | 2007-11-08 | Nippon Steel Corp | Corrosion amount measuring sensor |
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