CN216284522U - CEMS sampling system for horizontal flue of main discharge port of coal-fired unit - Google Patents
CEMS sampling system for horizontal flue of main discharge port of coal-fired unit Download PDFInfo
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Abstract
The utility model relates to a CEMS sampling system of a main discharge port horizontal flue of a coal-fired unit, which comprises a sampling branch pipe, a back-flushing electromagnetic valve, a sampling electromagnetic valve, a mixing main pipe, a flow regulating valve, a dilution unit and a probe controller, wherein the sampling branch pipe is connected with the back-flushing electromagnetic valve; a plurality of groups of sampling branch pipes are arranged on the measuring section of the main exhaust flue, the plurality of sampling branch pipes form a group, the lengths of the sampling branch pipes in the same group are arranged in an equal difference mode, and the tops of the sampling branch pipes are equal in height; each sampling branch pipe is connected to a mixing main pipe through a sampling electromagnetic valve and a flow regulating valve in sequence, and the mixing main pipe is connected to a gas analyzer through a dilution unit and a probe controller in sequence; the outlet pipeline of each sampling branch pipe is connected with a back-blowing pipeline, and a back-blowing electromagnetic valve is arranged on the back-blowing pipeline. The utility model has the beneficial effects that: the utility model adopts multi-point sampling of the main discharge outlet of the coal-fired unit, and can eliminate the problem of non-uniform pollutant concentration field caused by a flow field, thereby eliminating the defect that single-point measurement data cannot represent the whole pollutant discharge condition.
Description
Technical Field
The utility model relates to a sampling system, in particular to a CEMS sampling system for a horizontal flue of a total discharge port of a coal-fired unit.
Background
In order to strengthen the monitoring and supervision of the smoke emission of fixed pollution sources (thermal power plant boilers, industrial furnaces and the like which take solid and liquid as fuels or raw materials) and improve the continuous monitoring and management level of the smoke emission of the fixed pollution sources, all national pollutant emission enterprise units are provided with online continuous monitoring equipment and are connected with a network for data transmission.
All equipment required for continuously monitoring the emission concentration and emission amount of fixed pollution source particles and gaseous pollutants is called CEMS for short. The CEMS consists of a particulate matter monitoring unit, a gaseous pollutant monitoring unit, a smoke parameter monitoring unit and a data acquisition and processing unit, can monitor the concentration of gaseous pollutants, particulate matters and smoke parameters in real time, and calculates the discharge rate and the discharge amount. The installation position of the monitoring unit requires that the position of a measuring point should avoid a flue elbow and a part with a sharply changed section.
As part of coal-fired power plants are constructed earlier, in recent years, the ultra-low emission reconstruction of coal-fired units adds environment-friendly equipment for dust removal, desulfurization and the like in a plant area without redundant plots, and the existing units in the plant area are discharged by two furnaces sharing the same chimney, the monitoring unit is arranged at the horizontal flue section before the discharged flue gas enters the chimney, but the horizontal flue section is shorter, the distance between the front flue elbow and the rear flue elbow can not meet the condition that the particle CEMS and the flow rate CMS are arranged in the downstream direction of the elbow, the valve and the reducer pipe and are more than or equal to 4 times of the diameter of the flue, and the position which is more than or equal to 2 times of the diameter of the flue and is far from the upstream direction of the components, the CEMS is arranged at the position which is more than or equal to 2 times of the diameter of the flue and is far from the elbow, the valve and the downstream direction of the reducer pipe, and the requirement that the diameter of the flue is more than or equal to 0.5 times of the upstream direction of the part (the rectangular flue is calculated by equivalent diameter), and the situation that large deviation exists between CEMS monitoring data and manual sampling data exists. Because the horizontal space of a factory is limited, no redundant space is used for lengthening and transforming a flue, and the reconstruction cost of a chimney is too high, the problem under the condition needs to be solved by a single-point sampling technology different from the traditional total discharge port, and the CEMS data is ensured to be real and reliable.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects in the prior art and provides a CEMS sampling system for a horizontal flue of a total discharge outlet of a coal-fired unit.
The CEMS sampling system for the main discharge port horizontal flue of the coal-fired unit comprises a sampling branch pipe, a back-flushing electromagnetic valve, a sampling electromagnetic valve, a mixing main pipe, a flow regulating valve, a dilution unit and a probe controller; a plurality of groups of sampling branch pipes are arranged on the measuring section of the main exhaust flue, the plurality of sampling branch pipes form a group, the lengths of the sampling branch pipes in the same group are arranged in an equal difference mode, and the tops of the sampling branch pipes are equal in height; each sampling branch pipe is connected to a mixing main pipe through a sampling electromagnetic valve and a flow regulating valve in sequence, and the mixing main pipe is connected to a gas analyzer through a dilution unit and a probe controller in sequence; the outlet pipeline of each sampling branch pipe is connected with a back-blowing pipeline, and a back-blowing electromagnetic valve is arranged on the back-blowing pipeline.
Preferably, the method comprises the following steps: and the top end of the sampling branch pipe is provided with a filter element.
Preferably, the method comprises the following steps: the sampling branch pipe is provided with an electric heating device and a constant temperature device.
Preferably, the method comprises the following steps: the shell of the mixing main pipe is provided with an electric heating device and a heat preservation device.
Preferably, the method comprises the following steps: the outlet of the mixing main pipe is connected to the dilution unit after being converged into one path by two paths.
Preferably, the method comprises the following steps: the dilution unit is provided with a jet pump.
Preferably, the method comprises the following steps: the probe controller is provided with a standard gas interface and a back flushing interface.
The utility model has the beneficial effects that:
1. the utility model adopts multi-point sampling of the main discharge outlet of the coal-fired unit, and can eliminate the problem of non-uniform pollutant concentration field caused by a flow field, thereby eliminating the defect that single-point measurement data cannot represent the whole pollutant discharge condition.
2. The utility model adopts the mixing main pipe and heats and preserves the temperature of the main pipe, thereby avoiding the problem of pollutant concentration reduction caused by flue gas cooling, reducing the use amount of the dilution probe and reducing the engineering cost.
Drawings
FIG. 1 is a schematic diagram of a CEMS sampling system of a horizontal flue of a total discharge port of a coal-fired unit;
fig. 2 is a schematic diagram of a sampling system location.
Description of reference numerals: 1. sampling branch pipes; 2. a back-flushing electromagnetic valve; 3. sampling an electromagnetic valve; 4. mixing the mother pipes; 5. a flow regulating valve; 6. a gas analyzer; 7. a main discharge flue; 8. a desulfurizing tower; 9. a wet electric precipitator; 10. the cross section position of the sampling system is located; 11. and (4) a chimney.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the utility model. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Example one
The embodiment of the application provides a CEMS sampling system for a main discharge port horizontal flue of a coal-fired unit, which comprises a sampling branch pipe 1, a back-flushing electromagnetic valve 2, a sampling electromagnetic valve 3, a mixing main pipe 4, a flow regulating valve 5, a diluting unit and a probe controller. On the measuring section of the total exhaust flue 7, a plurality of sampling branch pipes 1 are arranged in a group and are approximately arranged at the same horizontal position, namely the tops of the sampling branch pipes 1 are equal in height, the lengths of the sampling branch pipes 1 in the same group are selected in an equal difference mode, and a plurality of groups are arranged in the horizontal direction of the total exhaust flue 7. Each sampling branch pipe 1 is connected to a mixing main pipe 4 sequentially through a sampling electromagnetic valve 3 and a flow regulating valve 5, and the mixing main pipe 4 is connected to a gas analyzer 6 through a dilution unit and a probe controller. The outlet pipeline of each sampling branch pipe 1 is connected with a back-blowing pipeline, a back-blowing electromagnetic valve is arranged on the back-blowing pipeline, and back-blowing compressed air enters the sampling branch pipes 1 through the back-blowing electromagnetic valve 2 to be blown.
The whole sampling branch pipe 1 is electrically heated and kept at a constant temperature, SO that pollutants (SO) are prevented from being monitored2) The condensate dilution affects the measurement results.
The shell of the mixed main pipe 4 contains electric heating and heat preservation, and the monitoring of pollutants (SO) is avoided2) Influence of SO on condensation before entering dilution unit2And (6) measuring the result.
The outlet of the mixing main pipe 4 is converged by two paths into one path and then enters the diluting unit, so that the phenomenon that the part far away from the outlet in the mixing main pipe is insufficient in draft force due to the single path to cause local product blockage is avoided.
The flow regulating valve 5 sets the flow opening of each branch pipe to a certain value according to the change condition of the flue gas flow velocity at each site measured by multiple working conditions on site, and the sampling system does not need to be adjusted and controlled along with the fluctuation of the load during the commissioning.
The dilution unit comprises a jet pump, smoke is extracted and diluted at constant flow by using the sonic orifice, and the flow is adjustable. The diluted flue gas reduces the requirement on rear section heating and heat preservation, and improves the measurement accuracy.
The probe controller comprises a standard gas interface and a back flushing interface, can calibrate the sampling system and the gas analyzer 6 regularly and calibrate the response time, and calibrates the sampling system and the gas analyzer by adopting standard gas when power plant maintenance personnel regularly and manually patrol, such as once per week.
Example two
The second embodiment of the application provides a working method of a CEMS sampling system of a total discharge port horizontal flue of a coal-fired unit, which comprises the following steps:
s1, enabling flue gas at an outlet of a desulfurizing tower 8(FGD) or an outlet of a wet electric precipitator 9(WESP) to flow through the section where a flue gas sampling branch pipe 1 is located, enabling the flue gas to enter the sampling branch pipe 1 of clean flue gas through each branch pipe sampling hole, then converging the flue gas into a mixing main pipe 4 of the clean flue gas, and then entering a total discharge opening CEMS meter (namely a gas analyzer 6) to measure the concentration of pollutants in the flue gas on line in real time;
s2, the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 are all remote control valves, and the sampling electromagnetic valve 3 is opened and the back-blowing electromagnetic valve 2 is closed in the conventional situation. The sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 on one sampling branch pipe 1 are one unit, the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 on one unit are sequentially actuated in a timing and sequential manner, the sampling electromagnetic valve 3 is switched off and the back-blowing electromagnetic valve 2 is switched on, and the back-blowing is carried out on the sampling branch pipe 1 by utilizing plant compressed air.
S3, the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 of the other units are not actuated during the back-blowing period of the unit in the step S2, namely the sampling electromagnetic valve 3 is opened and the back-blowing electromagnetic valve 2 is closed, after the back-blowing is finished, the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 of the unit are recovered to the normal state, namely the sampling electromagnetic valve 3 is opened and the back-blowing electromagnetic valve 2 is closed, the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 of the next unit start to repeat the step S2 to carry out back-blowing, and then the normal state is recovered, and the sampling electromagnetic valve 3 and the back-blowing electromagnetic valve 2 of each unit work in a circulating mode, so that the sampling and the back-blowing are carried out simultaneously.
And S4, regularly carrying out back blowing on the probe controller and the dilution unit.
EXAMPLE III
A chimney of a certain coastal coal-fired power plant unit is a chimney shared by two units, a CEMS measuring point of clean flue gas of each unit is arranged on a straight pipe section from an outlet of a desulfurizing tower (FGD) to the chimney, an original sampling system is single-point and is positioned in the middle of the top of a flue, and the problems of complex flue gas flow field, poor representativeness of the measuring point and the like exist. A set of sampling system is newly added, the structure of the sampling system comprises a sampling branch pipe 1, a back flushing electromagnetic valve 2, a sampling electromagnetic valve 3, a mixing main pipe 4, a flow regulating valve 5, a dilution unit and a probe controller, the sampling system is positioned at the top of a horizontal straight pipe section rectangular flue from a desulfurizing tower (FGD) outlet to a chimney, and the section size (without an insulating layer) of the rectangular flue is 5.2m (horizontal) multiplied by 11.6m (vertical). After the field multi-working condition test, the concentration fields of nitrogen oxides and sulfur dioxide on the cross section are analyzed, 9 sampling points are selected and divided into 3 groups, the length of each group of sampling branch pipes 1 is 0.8m, 1.8m and 2.8m respectively, the distance between every two pipes in the group is 20mm, and the distance between every two groups is 1.5 m. The inner diameter of the sampling branch pipe is 13mm, and the outer diameter is 17 mm. The original flue gas passes through FGD desulfurization and a wet electric dust collector in sequence, then flows through a flue of a horizontal straight pipe section at the inlet of a chimney, a sampling system simultaneously extracts clean flue gas at 9 points, the flue gas is coarsely filtered by a filter element and then enters a mixing main pipe 4, and the flue gas is mixed and then enters a dilution unit and a probe controller and finally enters a gas analyzer 6. The whole process from the sampling branch pipe 1 to the mixing main pipe 4 to the dilution unit is electrically heated and insulated, so that negative deviation of the measured item data caused by condensation of the sample gas is avoided. Sampling solenoid valve 3 and blowback solenoid valve 2 are the remote control valve, sampling solenoid valve 3 opens under the conventional condition, blowback solenoid valve 2 closes, when getting into the blowback link, regard as a unit with sampling solenoid valve 3 and blowback solenoid valve 2 on a sampling branch pipe 1, 9 units turn right from a left side and number a in proper order in this embodiment, b, c … … h, i, regularly in proper order control moves sampling solenoid valve 3 and blowback solenoid valve 2 on the same unit in proper order, the action is for closing sampling solenoid valve 3 and opening blowback solenoid valve 2, utilize the factory compressed air to carry out the blowback to sampling branch pipe 1. and (3) the sampling electromagnetic valves 3 and the back-blowing electromagnetic valves 2 of other units in the back-blowing period of the unit a do not act, the sampling electromagnetic valves 3 and the back-blowing electromagnetic valves 2 of the unit a recover the original states after the back-blowing is finished, the sampling electromagnetic valves 3 and the back-blowing electromagnetic valves 2 of the next unit (unit b) start the back-blowing step, and the back-blowing of the unit c is carried out until the unit i is finished, so that the real-time sampling and the back-blowing of the whole sampling system are carried out simultaneously. And maintenance personnel regularly perform back blowing and standard gas calibration on the probe controller and the dilution unit, so that the effectiveness and the accuracy of analysis data are ensured.
The material of the sampling branch pipe and the mixing main pipe is 316L, and the sampling branch pipe and the mixing main pipe are electrically heated and insulated at 140 ℃. The compression blowback pressure is 0.4MPa, and the pressure of the diluent gas is 0.4 MPa. The field test effect ratio of this example is shown in table 1 below:
TABLE 1 comparison of the results of the field test in this example
Note: the sampling system and the original sampling system are positioned in the same horizontal straight pipe section rectangular flue, and the vertical section space of the two sampling systems is less than 1 m.
The field test adopts the manual grid method to detect the emission concentration of the smoke pollutants at the main discharge port of the unit at the test section, compares the emission concentration data of the pollutants in the embodiment and the original sampling system at the same time period with the manual sampling data, and can find that the absolute error between the embodiment and the manual data of the nitrogen oxide project is 0.4mg/m3(Standard, 6% O)2) Less than the absolute error of the original sampling system and the artificial data by 0.7mg/m3(Standard, 6% O)2) (ii) a The absolute error between the sulfur dioxide project of the embodiment and the artificial data is 0.9mg/m3(Standard, 6% O)2) Less than 1.5mg/m of absolute error between the original sampling system and the artificial data3(Standard, 6% O)2)。
Because the positions of the monitoring points of the main discharge ports of part of the units can not meet the requirements, the flow field of the section is disordered, and the pollutant concentration distribution is uneven, the utility model adopts the multi-point sampling of the main discharge ports of the coal-fired units, and can eliminate the problem of uneven pollutant concentration field caused by the flow field, thereby eliminating the defect that single-point measurement data can not represent the whole pollutant discharge condition.
The utility model adopts the mixing main pipe and heats and preserves the temperature of the main pipe, thereby avoiding the problem of pollutant concentration reduction caused by flue gas cooling, reducing the usage amount of the dilution probe, reducing the engineering cost and simplifying the multipoint sampling control logic.
Claims (7)
1. A CEMS sampling system for a horizontal flue of a total discharge port of a coal-fired unit is characterized in that: the device comprises a sampling branch pipe (1), a back-blowing electromagnetic valve (2), a sampling electromagnetic valve (3), a mixing main pipe (4), a flow regulating valve (5), a diluting unit and a probe controller; a plurality of groups of sampling branch pipes (1) are arranged on the measuring section of the total exhaust flue (7), the plurality of sampling branch pipes (1) form a group, the sampling branch pipes (1) in the same group are arranged in an equal difference mode, and the tops of the sampling branch pipes (1) are equal in height; each sampling branch pipe (1) is connected to a mixing main pipe (4) sequentially through a sampling electromagnetic valve (3) and a flow regulating valve (5), and the mixing main pipe (4) is connected to a gas analyzer (6) sequentially through a dilution unit and a probe controller; the outlet pipeline of each sampling branch pipe (1) is connected with a back-blowing pipeline, and a back-blowing electromagnetic valve (2) is arranged on the back-blowing pipeline.
2. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: and the top end of the sampling branch pipe (1) is provided with a filter element.
3. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: the sampling branch pipe (1) is provided with an electric heating device and a constant temperature device.
4. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: the shell of the mixing main pipe (4) is provided with an electric heating device and a heat preservation device.
5. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: the outlet of the mixing main pipe (4) is converged into one path by two paths and then connected to the dilution unit.
6. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: the dilution unit is provided with a jet pump.
7. The CEMS sampling system for the total discharge horizontal flue of the coal-fired unit as claimed in claim 1, wherein: the probe controller is provided with a standard gas interface and a back flushing interface.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202122518610.9U CN216284522U (en) | 2021-10-20 | 2021-10-20 | CEMS sampling system for horizontal flue of main discharge port of coal-fired unit |
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| CN202122518610.9U CN216284522U (en) | 2021-10-20 | 2021-10-20 | CEMS sampling system for horizontal flue of main discharge port of coal-fired unit |
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