CN111610044B - Method for measuring, evaluating and calculating cooling air volume of dry-type slag extractor - Google Patents
Method for measuring, evaluating and calculating cooling air volume of dry-type slag extractor Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 43
- 238000001816 cooling Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 21
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 75
- 239000001301 oxygen Substances 0.000 claims abstract description 75
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 75
- 238000012360 testing method Methods 0.000 claims abstract description 21
- 238000005259 measurement Methods 0.000 claims abstract description 14
- 238000002485 combustion reaction Methods 0.000 claims description 28
- 239000000843 powder Substances 0.000 claims description 22
- 239000003245 coal Substances 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 7
- 238000002360 preparation method Methods 0.000 claims description 6
- 239000002918 waste heat Substances 0.000 claims description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 5
- 239000003546 flue gas Substances 0.000 claims description 5
- 230000001174 ascending effect Effects 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 3
- 238000010298 pulverizing process Methods 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 238000011156 evaluation Methods 0.000 abstract description 3
- 239000002956 ash Substances 0.000 description 6
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000002650 habitual effect Effects 0.000 description 3
- 239000000779 smoke Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000010884 boiler slag Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M99/00—Subject matter not provided for in other groups of this subclass
- G01M99/005—Testing of complete machines, e.g. washing-machines or mobile phones
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J1/00—Removing ash, clinker, or slag from combustion chambers
- F23J1/06—Mechanically-operated devices, e.g. clinker pushers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M99/00—Subject matter not provided for in other groups of this subclass
- G01M99/008—Subject matter not provided for in other groups of this subclass by doing functionality tests
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/418—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
- G05B19/4183—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by data acquisition, e.g. workpiece identification
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Quality & Reliability (AREA)
- Automation & Control Theory (AREA)
- Regulation And Control Of Combustion (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
The invention relates to a method for measuring, evaluating and calculating cooling air volume of a dry-type slag extractor, which comprises the following steps: the first step is as follows: preparing for the early stage of the measurement test; the second step is that: determining the stable operation condition of the boiler; the third step: adjusting the unit load to a rated load; the fourth step: recording the running parameters and measuring the oxygen quantity of an inlet and an outlet of the air preheater; and a sixth step: recording operation data and measuring the oxygen quantity of an inlet and an outlet of the air preheater; the seventh step: and calculating the air quantity entering the hearth under the rated load. The method is simple in calculation and reliable in evaluation.
Description
Technical Field
The invention relates to the technical field of performance evaluation of boiler auxiliary equipment, in particular to a method for measuring, evaluating and calculating cooling air volume of a solid-state deslagging dry type slag extractor of a coal-fired boiler.
Background
Compared with an air-cooled dry slag extractor, the wet slag extractor has the advantages that water resources are wasted, and a great operation risk exists for a boiler which is easy to coke in a hearth in a large area, namely, when a large number of coke blocks fall into a water seal tank, a large amount of steam is generated, so that parameters such as hearth negative pressure, combustor fire detection intensity, steam drum water level and the like are easy to fluctuate violently, and further, boiler MFT action is caused, and the boiler extinguishes fire. But also has an obvious advantage that the bottom of the wet slag conveyor leaks little.
With the continuous maturity of air-cooled dry slag extractor technology, in order to reduce the fire extinguishing risk of boiler operation, the electric power plant in south net of Hebei province changes the wet slag extractor into a dry slag extractor, meanwhile, as the environmental protection requirement is more and more strict, a series of technical innovations such as low nitrogen modification, denitration modification, air preheater cold section modification, low pressure coal economizer modification and the like are basically carried out, after the boiler operates for several years, parameter comparison shows that the exhaust gas temperature of the boiler is higher by 8-10 ℃ than that of the previous years, one of the doubts is caused by the fact that the air leakage at the bottom of a hearth is large due to the dry slag extractor, the related standard JB/T12120-2015 air-cooled dry slag extraction system is consulted, wherein 5.1.5 expresses that the air quantity of cooling air entering the hearth of the dry slag extraction system is not more than 1.0% of the total air quantity of the boiler combustion under the normal working condition, but 6.3.3 system cooling air quantity measurement and calculation in the standard can not be realized fundamentally in field test, therefore, a new measurement method needs to be invented for evaluating the performance of the dry slag discharging system.
Disclosure of Invention
The invention provides a method for measuring the cooling air volume of a solid-state deslagging dry-type slag extractor of a coal-fired boiler, which makes up the defects of the prior art and has operability in measuring the cooling air volume of the dry-type slag extractor.
The technical scheme of the invention is as follows:
furnace export oxygen volume is by coal type, coal volume, amount of wind decision, and when coal type and coal volume are definite, the amount of wind that gets into the boiler is just big when big, vice versa, and to the boiler of storage pulverizing system in being equipped with, the amount of wind that gets into the boiler includes: primary air quantity, secondary air quantity, tertiary air quantity, furnace bottom air leakage (namely cooling air quantity of a dry slag extractor), hearth air leakage, front flue air leakage of an oxygen meter and the like. When the load of the unit is unchanged, the total coal quantity of the boiler is unchanged, if the oxygen quantity of the hearth outlet is kept unchanged, the air quantity entering the boiler needs to be kept constant, and if the air leakage at the bottom of the boiler is reduced, the air quantity can be increased through manual control. The increased air quantity mostly enters the hearth, and a small part leaks into the flue. Wherein the air quantity entering the hearth is the air quantity leaked from the bottom of the furnace, namely the cooling air quantity of the dry slag extractor.
A method for measuring, evaluating and calculating cooling air volume of a dry-type slag extractor comprises the following steps:
the first step is as follows: preliminary preparation work for measurement test
(1) And calibrating the oxygen quantity of the hearth outlet, the air quantity of the primary fan and the air quantity of the air feeder, and determining that the data display of the DCS dial is accurate.
(2) The powder level of the powder bin is improved.
(3) The hydraulic shutoff door of the cold ash bucket of the movable boiler ensures the flexible opening and closing.
(4) The sealing condition of the hearth is checked, all the observation holes are closed, and air leakage of the hearth is avoided.
(5) A sufficient amount of a constant coal species was prepared.
The second step is that: determining the stable operation condition of the boiler:
(1) the unit can keep the rated load to stably operate for 4 hours.
(2) During the test period, the powder making system is completely shut down, and the baffle is closed.
(3) And closing the continuous exhaust valve and stopping the operation of the flue gas waste heat utilization system.
(4) The negative pressure of the hearth is automatically input, the oxygen amount at the outlet of the hearth is automatically released, and manual operation is changed.
The third step: after the load of the unit is adjusted to the rated load
At the moment, the negative pressure of the hearth is kept at about-50 Pa, the oxygen amount is kept at about 4%, the boiler stably runs for 30 minutes, and the boiler operation data including the operation parameters such as primary air quantity (AQ 1 (t/h) and BQ2 (t/h)), blower air quantity (AQ 2 (t/h) and BQ2 (t/h)), the oxygen amount of the hearth outlet, the negative pressure of the hearth, the smoke exhaust temperature and the like are recorded; and measuring the oxygen quantity of the inlet and the outlet of the air preheater, calculating the air leakage rate (eta A and eta B) of the air preheater on two sides, and taking 60 minutes in the measuring process.
The fourth step: after the operation parameters are recorded and the oxygen quantity of the inlet and the outlet of the air preheater is measured
And gradually closing all the hydraulic shutoff doors of the cold ash bucket. The oxygen content of the hearth outlet is gradually reduced, the oxygen content of the hearth outlet still has a descending trend due to untight shut-off doors after the shut-off doors are completely closed, along with accumulation of ash, air leakage gaps of the shut-off doors are continuously buried, and when the oxygen content is approximately flat and slow, the cooling air volume of the bottom of the hearth, namely a dry type slag extractor, is basically zero. The time period is basically 30-60 minutes, but the maximum time period is not more than 3 hours, otherwise, the measurement test is terminated, and the occurrence of boiler slag discharge fault is avoided.
The fifth step: keeping the primary air fan output unchanged
The output of blowers on two sides is gradually increased, and the negative pressure of the hearth is kept unchanged in the process until the oxygen content at the outlet of the hearth is recovered to about 4 percent. Recording boiler operation data including primary air volume (AQ '1 (t/h) and BQ' 2 (t/h)), blower air volume (AQ '2 (t/h) and BQ' 2 (t/h)), oxygen quantity at a hearth outlet, hearth negative pressure, smoke exhaust temperature and other operation parameters, measuring oxygen quantity at an inlet and an outlet of an air preheater, and calculating air leakage rates (eta 'A and eta' B) of the air preheaters at two sides.
And a sixth step: recording operation data and measuring oxygen quantity at inlet and outlet of air preheater
And informing operators to gradually open the hydraulic shutoff door, gradually reducing the output of the air feeder according to the change of the oxygen amount at the outlet of the hearth, so that the boiler is recovered to operate under the habitual operation, and ending the measurement test.
The seventh step: air quantity entering hearth under rated load is calculated
Neglecting a very small amount of air leakage of the hearth, closing the hydraulic shutoff door, removing a small part of the sum of the primary air and the secondary air entering the hearth to leak out of the flue, and taking the rest part as the combustion air volume Qr entering the hearth under the rated load of the boiler, wherein the calculation formula is (AQ '1 + AQ' 2) ((1-eta 'A) + (BQ' 1+ BQ '2) ((1-eta' B) (t/h).
Eighth step: calculation of cooling air volume of dry slag extractor under rated load
One part of the fan increment air quantity leaks into a flue, the majority of the fan increment air quantity enters a hearth, and the increment air quantity entering the hearth is the cooling air quantity Ql of the dry type slag extractor, namely (AQ '1 + AQ' 2) ((1-eta 'A) + (BQ' 1+ BQ '2) ((1-eta' B) - (AQ 1+ AQ 2) ((1-eta A) + (BQ 1+ BQ 2) ((1-eta B) (t/h)
The ninth step: calculation of ratio of cooling air volume to combustion air volume entering hearth
The ratio of the cooling air volume to the combustion air volume entering the hearth is Ql/Qr.
Furthermore, in the first step, in the early preparation work, (1) the air volume and oxygen volume calibration work of the fan is carried out under the rated load of the boiler, and the average value of the two working conditions is taken; (2) the powder level is increased to the highest powder level, the combustion quantity of the boiler in 4 hours is met, the starting of a powder making system is avoided, and air leakage of the powder making system and the entering of a hearth combustion system are avoided; (3) confirming whether the hydraulic shutoff door is closed in place or not, otherwise, abandoning the work before the test; (4) the stabilization of the coal for combustion is the basis of the test.
Furthermore, in the second step, the operation condition (1) should be applied for the middle adjustment in advance and approved; (2) the flue gas waste heat utilization system and the continuous exhaust are shut down, and the purpose is to ensure that a thermodynamic system is not influenced by non-quantitative factors; (3) the load of the hearth is kept stable, and the micro air leakage rate of the flue and the hearth is kept unchanged.
Furthermore, in the third step, important data are recorded, and the flow of the fan needs to be or converted into t/h.
Furthermore, in the fourth step, the oxygen content is reduced and finally tends to be gentle, and the judgment basis that whether the gap of the hydraulic shutoff door is buried and the air leakage is basically zero is judged.
Furthermore, in the fifth step, the oxygen amount at the outlet of the hearth is recovered to 4% of the original oxygen amount, which is not easy to be very accurate, the ascending and descending are adjusted to 4%, the average value of the two air amounts is taken, and the error is reduced.
Furthermore, in the seventh step, the air leakage condition of the air preheater is considered in the calculation of the combustion air quantity entering the hearth method, so that the error is reduced, the calculation formula is not strictly derived, and the error is within 1% through multi-data comparison. The performance of the dry-type slag extractor can be judged according to the ratio of the cooling air volume to the combustion air volume entering the hearth.
Furthermore, in the eighth step, the air quantity of the boiler participating in combustion mainly comprises three parts, namely, the cooling air quantity of the primary air, the secondary air and the slag drying machine, the total coal quantity and the oxygen quantity of the outlet of the hearth are unchanged, namely, the total air quantity participating in combustion is unchanged, and the cooling air quantity of the slag dry-off system is equal to the air quantity increment of the primary air and the secondary air entering the hearth.
The invention has the beneficial effects that:
the method is simple in calculation and reliable in evaluation.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
In the attached drawing, 1-a dry slag extractor, 2-a hydraulic shutoff door, 3-a primary air fan, 4-a blower, 5-a primary air fan flowmeter, 6-a blower flowmeter, 7-a furnace outlet oxygen gauge, 8-an air preheater inlet oxygen measurement point, 9-an air preheater outlet oxygen measurement point and 10-an air preheater.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
Spatially relative terms, such as "above … …", "above … …", "above … …", "above", and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of protection of the present application is not to be construed as being limited.
The technical solution and structure of the present invention will be described in further detail with reference to the accompanying drawings.
Furnace export oxygen volume is by coal type, coal volume, amount of wind decision, and when coal type and coal volume are definite, the amount of wind that gets into the boiler is just big when big, vice versa, and to the boiler of storage pulverizing system in being equipped with, the amount of wind that gets into the boiler includes: primary air quantity, secondary air quantity, tertiary air quantity, furnace bottom air leakage (namely cooling air quantity of a dry slag extractor), hearth air leakage, front flue air leakage of an oxygen meter and the like. When the load of the unit is unchanged, the total coal quantity of the boiler is unchanged, if the oxygen quantity of the hearth outlet is kept unchanged, the air quantity entering the boiler needs to be kept constant, and if the air leakage at the bottom of the boiler is reduced, the air quantity can be increased through manual control. The increased air quantity mostly enters the hearth, and a small part leaks into the flue. Wherein the air quantity entering the hearth is the air quantity leaked from the bottom of the furnace, namely the cooling air quantity of the dry slag extractor.
A method for measuring, evaluating and calculating cooling air volume of a dry-type slag extractor comprises the following steps:
the first step is as follows: preliminary preparation work for measurement test
(1) And calibrating the oxygen quantity of the hearth outlet, the air quantity of the primary fan and the air quantity of the air feeder, and determining that the data display of the DCS dial is accurate.
(2) The powder level of the powder bin is improved.
(3) The hydraulic shutoff door of the cold ash bucket of the movable boiler ensures the flexible opening and closing.
(4) The sealing condition of the hearth is checked, all the observation holes are closed, and air leakage of the hearth is avoided.
(5) A sufficient amount of a constant coal species was prepared.
The second step is that: determining the stable operation condition of the boiler:
(1) the unit can keep the rated load to stably operate for 4 hours.
(2) During the test period, the powder making system is completely shut down, and the baffle is closed.
(3) And closing the continuous exhaust valve, and stopping the operation of the flue gas waste heat utilization system.
(4) The negative pressure of the hearth is automatically input, the oxygen amount at the outlet of the hearth is automatically released, and manual operation is changed.
The third step: after the load of the unit is adjusted to the rated load
At the moment, the negative pressure of the hearth is kept at about-50 Pa, the oxygen content is kept at about 4%, the boiler stably runs for 30 minutes, and boiler operation data including primary air volume (AQ 1 (t/h) and BQ2 (t/h)), blower air volume (AQ 2 (t/h) and BQ2 (t/h)), the oxygen content of the hearth outlet, the negative pressure of the hearth, the exhaust gas temperature and other operation parameters are recorded; and measuring the oxygen quantity of the inlet and the outlet of the air preheater, calculating the air leakage rate (eta A and eta B) of the air preheater on two sides, and taking 60 minutes in the measuring process.
The fourth step: after the operation parameters are recorded and the oxygen quantity of the inlet and the outlet of the air preheater is measured
And gradually closing all the hydraulic shutoff doors of the cold ash bucket. The oxygen content of the hearth outlet is gradually reduced, the oxygen content of the hearth outlet still has a descending trend due to untight shut-off doors after the shut-off doors are completely closed, along with accumulation of ash, air leakage gaps of the shut-off doors are continuously buried, and when the oxygen content is approximately flat and slow, the cooling air volume of the bottom of the hearth, namely a dry type slag extractor, is basically zero. The time period is basically 30-60 minutes, but the maximum time period is not more than 3 hours, otherwise, the measurement test is terminated, and the occurrence of boiler slag discharge fault is avoided.
The fifth step: keeping the primary air fan output unchanged
The output of blowers on two sides is gradually increased, and the negative pressure of the hearth is kept unchanged in the process until the oxygen content at the outlet of the hearth is recovered to about 4 percent. Recording boiler operation data including primary air volume (AQ '1 (t/h) and BQ' 2 (t/h)), blower air volume (AQ '2 (t/h) and BQ' 2 (t/h)), oxygen quantity at a hearth outlet, hearth negative pressure, smoke exhaust temperature and other operation parameters, measuring oxygen quantity at an inlet and an outlet of an air preheater, and calculating air leakage rates (eta 'A and eta' B) of the air preheaters at two sides.
And a sixth step: recording operation data and measuring oxygen quantity at inlet and outlet of air preheater
And informing operators to gradually open the hydraulic shutoff door, gradually reducing the output force of the air feeder according to the change of the oxygen amount at the outlet of the hearth, recovering the operation of the boiler to the operation under the habitual operation, and ending the measurement test.
The seventh step: air quantity entering hearth under rated load is calculated
Neglecting a very small amount of air leakage of the hearth, closing the hydraulic shutoff door, removing a small part of the sum of the primary air and the secondary air entering the hearth to leak out of the flue, and taking the rest part as the combustion air volume Qr entering the hearth under the rated load of the boiler, wherein the calculation formula is (AQ '1 + AQ' 2) ((1-eta 'A) + (BQ' 1+ BQ '2) ((1-eta' B) (t/h).
Eighth step: calculation of cooling air volume of dry slag extractor under rated load
One part of the fan increment air quantity leaks into a flue, the majority of the fan increment air quantity enters a hearth, and the increment air quantity entering the hearth is the cooling air quantity Ql of the dry type slag extractor, namely (AQ '1 + AQ' 2) ((1-eta 'A) + (BQ' 1+ BQ '2) ((1-eta' B) - (AQ 1+ AQ 2) ((1-eta A) + (BQ 1+ BQ 2) ((1-eta B) (t/h)
The ninth step: calculation of ratio of cooling air volume to combustion air volume entering hearth
The ratio of the cooling air volume to the combustion air volume entering the hearth is Ql/Qr.
Furthermore, in the first step, in the early preparation work, (1) the air volume and oxygen volume calibration work of a fan is carried out under the rated load of the boiler, and the average value of the two working conditions is taken; (2) the powder level is increased to the highest powder level, the combustion quantity of the boiler in 4 hours is met, the starting of a powder making system is avoided, and air leakage of the powder making system and the entering of a hearth combustion system are avoided; (3) confirming whether the hydraulic shutoff door is closed in place or not, otherwise, abandoning the work before the test; (4) the stabilization of the coal for combustion is the basis of the test.
Further, in the second step, the operation condition (1) should be applied for the middle adjustment in advance and approved; (2) the purpose of stopping the flue gas waste heat utilization system and the continuous emission is to ensure that a thermodynamic system is not influenced by non-quantitative factors; (3) the load of the hearth is kept stable, and the micro air leakage rate of the flue and the hearth is kept unchanged.
Furthermore, in the third step, important data are recorded, and the flow of the fan needs to be or converted into t/h.
Furthermore, in the fourth step, the oxygen amount is reduced and finally tends to be gentle, which is a judgment basis for judging whether the gap of the hydraulic shutoff door is buried and the air leakage is basically zero.
Furthermore, in the fifth step, the oxygen amount at the outlet of the hearth is recovered to 4% of the original oxygen amount, which is not easy to be very accurate, the ascending and descending are adjusted to 4%, the average value of the two air amounts is taken, and the error is reduced.
Furthermore, in the seventh step, the air leakage condition of the air preheater is considered in the calculation of the combustion air quantity entering the hearth method, so that the error is reduced, the calculation formula is not strictly derived, and the error is within 1% through multi-data comparison. The performance of the dry slag extractor can be judged according to the ratio of the cooling air volume to the combustion air volume entering the hearth.
Furthermore, in the eighth step, the air quantity of the boiler participating in combustion mainly comprises three parts, namely, the cooling air quantity of primary air, secondary air and a slag drying machine, the total coal quantity and the oxygen quantity of a hearth outlet are unchanged, namely, the total air quantity participating in combustion is unchanged, and the cooling air quantity of a slag dry-discharging system is equal to the air quantity increment of the primary air and the secondary air entering the hearth.
Example 1
As shown in FIG. 1, the invention takes a 300MW Zhongke powder process system boiler of a certain power plant of the south network of Hebei as an example.
The first step is as follows: and (5) early preparation work. The calibration work of the oxygen quantity at the outlet of the hearth and the air quantity of the fan is carried out recently, and the data fluctuation is reasonable; the fuel part prepares stable coal for 3 days and is full of a No. 4 boiler bunker; the heating surface of a boiler hearth is comprehensively checked, a burner area and a fire observation hole at the upper part are closed, and the air leakage points of the hearth mainly comprise a soot blower hole and an industrial television hole and are small; and starting 4 sets of powder making systems to increase the powder level to a high powder level, stopping the operation before the test, and preparing the powder conveying in the furnace.
The second step is that: and (4) closing the continuous exhaust and waste heat utilization system, releasing AGC, adjusting the negative pressure of the hearth to-50 Pa, and adjusting the oxygen content to be 4% on average on the left side and the right side.
The third step: and stabilizing for 20-30 minutes, and recording dial data, wherein the total air volume of the fan on the first side is 605t/h, and the total air volume of the fan on the first side is 594 t/h. In order to measure the oxygen quantity of the inlet and the outlet of the air pre-heaters on two sides simultaneously, the time is 45 minutes. The air leakage rates of the two sides are respectively 7.2 percent and 8.5 percent
The fourth step: the hydraulic baffle is gradually closed, the oxygen content is 4 percent, and finally is reduced to 3.7 percent, the oxygen content is gentle, and the time is 40 minutes.
The fifth step: the output of a blower is gradually improved, the oxygen quantity of a hearth outlet is adjusted to 4% in an ascending mode and a descending mode, the total air quantity of a first side fan is 623t/h and 624t/h respectively, the total air quantity of the first side fan is 618t/h and 622t/h respectively, and the air leakage rates of the two sides are 7.3% and 8.7% respectively.
And a sixth step: and informing operators of finishing the test, recovering the habitual operation, and putting the dry-type slag extractor into operation.
The seventh step: calculating the total air volume entering the hearth as follows: 623.5 × 1-7.3% +620 × 1-8.7% =1137.8 t/h.
The eighth step: and calculating the cooling air volume as follows: 623.5 × (1-7.3%) +620 × (1-8.7%) -605 × (1-7.2%) -594 × (1-8.5%) =32.8 t/h.
The ninth step: the ratio of the cooling air volume to the combustion air volume entering the hearth is 32.8/1137.8= 2.9%. The cooling air quantity of the dry slag extractor is larger.
The technical solutions in the embodiments of the present application are clearly and completely described above, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. The above description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Claims (1)
1. A method for measuring, evaluating and calculating cooling air volume of a dry type slag extractor is characterized by comprising the following steps:
the first step is as follows: preparing for the early stage of the measurement test;
the second step is that: determining the stable operation condition of the boiler;
the third step: adjusting the load of the unit to a rated load;
the fourth step: recording operation data and measuring the oxygen quantity of an inlet and an outlet of an air preheater;
the fifth step: keeping the output of the primary air fan unchanged;
and a sixth step: recording operation data and measuring the oxygen quantity of an inlet and an outlet of an air preheater;
the seventh step: calculating the air quantity entering the hearth under the rated load;
the first preliminary preparation work of the measurement test comprises the following steps:
(1) calibrating the oxygen quantity at the outlet of the hearth, the air quantity of a primary air fan and the air quantity of a blower, and determining that the data display of a DCS dial is accurate; the air quantity and the oxygen quantity of the fan are calibrated under the rated load of the boiler, and the average value of the two working conditions is taken;
(2) the powder level of the powder bin is improved, the 4-hour combustion amount of the boiler is met, and the powder making system is prevented from being started;
(3) the hydraulic shutoff door of the cold ash bucket of the movable boiler ensures flexible opening and closing; confirming whether the hydraulic shutoff door is closed in place;
(4) checking the sealing condition of the hearth, and closing all the observation holes to avoid air leakage of the hearth;
(5) preparing a sufficient amount of constant coal;
the second step of determining the conditions for stable operation of the boiler includes the following conditions:
(1) the unit keeps the stable operation of rated load and has the capability of 4 hours;
(2) during the test period, the pulverizing system is completely shut down, and the baffle is closed;
(3) closing the continuous exhaust valve, and stopping the operation of the flue gas waste heat utilization system;
(4) the negative pressure of the hearth is automatically input, the oxygen amount at the outlet of the hearth is automatically released, and manual operation is changed;
thirdly, after the load of the unit is adjusted to the rated load:
at the moment, the negative pressure of the hearth is kept between 40 Pa and 60Pa, the oxygen amount of an outlet is kept between 3 percent and 5 percent, the boiler stably runs for 30 minutes, and boiler running data including primary air quantity AQ1, BQ1, air quantity AQ2 of a blower, BQ2, the oxygen amount of the outlet of the hearth, the negative pressure of the hearth and the running parameters of the exhaust gas temperature are recorded; measuring the oxygen quantity of an inlet and an outlet of the air preheater, calculating air leakage rates eta A and eta B of the air preheater on two sides, wherein the measuring process takes 60 minutes;
recording data, and converting the flow of the fan into a unit of t/h;
and fourthly, after recording operation data and measuring the oxygen quantity of an inlet and an outlet of the air preheater:
gradually closing all hydraulic shutoff doors of a cold ash bucket, gradually reducing oxygen content at a hearth outlet, continuously burying an air leakage gap of the hydraulic shutoff doors due to untight hydraulic shutoff doors after all hydraulic shutoff doors are closed, and considering the cooling air volume of the dry type slag extractor to be zero when the oxygen content at the outlet tends to be flat and slow, wherein the time is 30-60 minutes, but the longest time is not more than 3 hours, otherwise, terminating the measurement test;
the oxygen content at the outlet is reduced and finally tends to be gentle, and the judgment basis for judging whether the gap of the hydraulic shutoff door is buried or not and zero air leakage is provided;
fifthly, keeping the output of the primary air fan unchanged, and then:
gradually increasing the output of blowers on two sides, keeping the negative pressure of the hearth unchanged in the process until the oxygen content at the outlet of the hearth is recovered to 3-5%, recording boiler operation data including primary air quantity AQ '1, BQ' 1, blower air quantity AQ '2, BQ' 2, oxygen content at the outlet of the hearth, negative pressure of the hearth and operation parameters of exhaust gas temperature, measuring the oxygen content at the inlet and the outlet of an air preheater, and calculating air leakage rates eta 'A and eta' B of the air preheaters on two sides;
the oxygen content at the outlet of the hearth is recovered to 4 percent of the original oxygen content, the ascending and descending are adjusted to 4 percent, and the average value of the air volume of the two times is taken;
and sixthly, after recording the operation data and measuring the oxygen quantity of an inlet and an outlet of the air preheater:
informing operators to gradually open the hydraulic shutoff door, gradually reducing the output of the air feeder according to the change of the oxygen amount at the outlet of the hearth, recovering the operation of the boiler to the operation under the daily operation, and ending the measurement test;
and seventhly, calculating the air volume entering the hearth under the rated load:
neglecting hearth air leakage, closing a hydraulic shutoff door, then removing air quantity leaked to the outside of a flue by the sum of primary air and secondary air quantity entering the hearth, and taking the rest part as combustion air quantity entering the hearth under the rated load of the boiler, wherein the calculation formula is as follows:
Qr=（AQ’1+AQ’2）*（1-η’A）+（BQ’1+BQ’2）*（1-η’B） t/h；
and the eighth step of calculating the cooling air volume of the dry-type slag extractor under rated load:
one part of fan increment air quantity leaks into a flue, the most part of fan increment air quantity enters a hearth, the increment air quantity entering the hearth is the cooling air quantity Ql of the dry slag extractor, and the calculation formula is as follows:
Ql=（AQ’1+AQ’2）*（1-η’A）+（BQ’1+BQ’2）*（1-η’B）-（AQ1+AQ2）*（1-ηA）-（BQ1+BQ2）*（1-ηB） t/h；
the air quantity of the boiler participating in combustion consists of three parts, namely primary air, secondary air and the cooling air quantity of the dry slag extractor, wherein the total coal quantity and the oxygen quantity of the hearth outlet are unchanged, which indicates that the total air quantity participating in combustion is unchanged, and the cooling air quantity of the dry slag extractor is equal to the air quantity increment of the primary air and the secondary air entering the hearth;
ninth step, calculating the ratio of cooling air volume to combustion air volume entering the hearth: the ratio of the cooling air volume to the combustion air volume entering the hearth is Ql/Qr.
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| CN113449954B (en) * | 2021-04-09 | 2023-10-24 | 苏州西热节能环保技术有限公司 | Method for measuring and calculating bottom air leakage rate of dry slag-discharging boiler |
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| CN102588986B (en) * | 2012-03-12 | 2014-07-02 | 河北省电力勘测设计研究院 | Optimized boiler designing method based on air cooling dry slagging technology |
| CN104132355A (en) * | 2014-07-25 | 2014-11-05 | 国家电网公司 | Dry-type deslagging system capable of adjusting cooling air |
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