Dcs automatic ash conveying logic system

Abstract

The application provides a DCS automatic ash conveying logic system, which comprises an ash conveying unit system and is divided into 13 ash conveying units, namely, an electric dust collector one electric field A1 column, an electric dust collector one electric field A2 column, an electric dust collector one electric field A3 column, a coal economizer A side, a coal economizer B side, an electric dust collector two electric field A column, an electric dust collector two electric field B column, an electric dust collector three electric field A column, an electric dust collector three electric field B column, an electric dust collector four electric field A column, an electric dust collector four electric field B column, an electric dust collector five electric field A column and an electric dust collector five electric field B column. The DCS automatic ash conveying logic system independently arranges the electric dust collector one electric field A1, A2 and A3 units, reasonably distributes the electric dust collector two electric field A / B and the coal economizer A / B ash conveying pipelines, solves the mutual influence and exclusion in the ash conveying process, reduces the ash conveying frequency, and avoids the phenomena of pipe blockage and high ash.

Description

Technical Field

[0001] This invention relates to the field of ash conveying logic system technology, specifically to a DCS automatic ash conveying logic system. Background Technology

[0002] The ash conveying system of the coal-fired unit adopts a positive pressure dense-phase pneumatic ash conveying system, which is a double-pipe type. The fly ash collected in the ash hoppers of the electrostatic precipitator and economizer is conveyed to the ash storage silo by the air pressure of the ash conveying air compressor; such as... Figure 1 As shown, the ash from the ash hoppers of the second, third, fourth, and fifth electric fields of the electrostatic precipitator can be sent to the original ash silo for sorting or to the fine ash silo for storage via the ash conveying pipeline branch valves. The existing ash conveying units in the existing electrostatic precipitator pneumatic ash conveying system of the power plant cannot operate according to the automatic ash conveying mode designed by the DCS, cannot adapt to the automatic ash conveying requirements of the electrostatic precipitator in the variable load section, and are prone to mutual exclusion of ash conveying units, resulting in poor ash conveying and affecting the safe and stable operation of the entire electrostatic precipitator ash conveying system, causing ash accumulation or blockage, requiring manual ash conveying operation via the DCS. Summary of the Invention

[0003] This invention proposes a DCS automatic ash conveying logic system, which solves the problems in the existing electrostatic precipitator pneumatic ash conveying system of power plants. These problems include the inability of each ash conveying unit to operate according to the automatic ash conveying mode designed by the DCS, the inability to adapt to the automatic ash conveying requirements of electrostatic precipitator in variable load sections, and the tendency for ash conveying units to crowd each other, resulting in poor ash conveying and affecting the safe and stable operation of the entire electrostatic precipitator ash conveying system, causing ash accumulation or ash blockage, and requiring manual DCS ash conveying operation.

[0004] The technical solution of this invention is implemented as follows:

[0005] The DCS automatic ash conveying logic system includes an ash conveying unit system, which is divided into 13 ash conveying units, namely:

[0006] Electrostatic precipitator, electric field A1 column, electrostatic precipitator, electric field A2 column, electrostatic precipitator, electric field A3 column;

[0007] Economizer A side, economizer B side;

[0008] Electrostatic precipitator, second electric field, column A; Electrostatic precipitator, second electric field, column B;

[0009] Column A of the three electric fields of the electrostatic precipitator; Column B of the three electric fields of the electrostatic precipitator;

[0010] Electrostatic precipitator four electric fields, column A; Electrostatic precipitator four electric fields, column B;

[0011] Electrostatic precipitator five-field column A, electrostatic precipitator five-field column B;

[0012] The electric precipitator one electric field A1 column is connected with an electric field A1 column raw ash storage and an electric field A1 column coarse ash storage through pipelines; the electric precipitator one electric field A2 column is connected with an electric field A2 column raw ash storage and an electric field A2 column coarse ash storage through pipelines; the electric precipitator one electric field A3 column is connected with an electric field A3 column raw ash storage and an electric field A3 column coarse ash storage through pipelines;

[0013] The electric precipitator two electric field A column, the electric precipitator two electric field B column, the economizer A side and the economizer B side are connected with the new raw ash storage and the new coarse ash storage through pipelines respectively;

[0014] The electric precipitator three electric field A column, the electric precipitator three electric field B column, the electric precipitator four electric field A column, the electric precipitator four electric field B column, the electric precipitator five electric field A column and the electric precipitator five electric field B column are connected with the ash removal storage through pipelines respectively.

[0015] Further, according to the historical operation investigation and the operation test situation after the ash conveying pipeline is transformed, the control logic is designed in a modular manner, 13 units of the ash conveying system are divided into five modules, the three modules of the electric precipitator one electric field A1 column, the electric precipitator one electric field A2 column and the electric precipitator one electric field A3 column account for a large proportion of the ash conveying amount and should be preferentially conveyed, a smaller ash conveying time interval or continuous conveying is adopted; the second is the electric precipitator two electric field A column, the electric precipitator two electric field B column, the economizer A side and the economizer B side; and the last is the electric precipitator three electric field A column, the electric precipitator three electric field B column, the electric precipitator four electric field A column, the electric precipitator four electric field B column, the electric precipitator five electric field A column and the electric precipitator five electric field B column.

[0016] Further, the ash conveying unit sub-modules are logically sorted in a fixed material falling time, ash conveying time and ash conveying sequence to form a semi-automatic ash conveying control logic; according to the coal quantity and the given coal ash content, the system automatic operation control is participated to realize the ash conveying automatic control and track the coal quantity and the coal quality.

[0017] Further, the historical operation data of the ash conveying system, the coal feeding quantity, the unit electric load and other data of the power plant are collected and analyzed to map the linear function relationship between the coal feeding quantity and the ash conveying system unit material falling time;

[0018] y=kx+b

[0019] y-ash conveying unit feeding valve opening time;

[0020] x-averaged value of the coal feeding quantity of the unit in a certain time period;

[0021] k-positive relationship number of the coal feeding quantity and the ash falling time;

[0022] b-correction linear relationship constant, ash conveying starting pressure, ending pressure, air inlet valve delay, exhaust and circulation time;

[0023] The function is connected to the ash conveying DCS control system, realizes automatic tracking of the change of the coal conveying amount, and changes the ash conveying system, so that the circulating efficiency of the ash conveying system is optimal.

[0024] The technical scheme provided in the application has the beneficial effects of:

[0025] The DCS automatic ash conveying logic system re-designs and optimizes the DCS ash conveying logic through the ash conveying pipeline system, re-integrates and distributes the ash conveying units, and comprehensively controls the coal amount and coal quality DCS automatic ash conveying logic device, realizes automatic control of the automatic material falling and ash conveying functions of each ash conveying unit of the pneumatic ash conveying system with the coal amount and coal quality parameters as independent variables, when a single ash conveying unit fails, the failed unit can be automatically or manually removed, without affecting the normal operation of the single subsystem and the entire ash conveying system, after the failed unit is removed, the ash conveying is manually intervened, and after the repair is normal, the automatic operation system is put into operation, and the normal automatic operation sequence of the subsystem is added. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 It is a schematic diagram of the prior art pneumatic ash conveying unit system;

[0028] Figure 2 It is a schematic diagram of the prior art pneumatic ash conveying module logic;

[0029] Figure 3 It is a schematic diagram of the pneumatic ash conveying unit system of the application;

[0030] Figure 4 It is a schematic diagram of the pneumatic ash conveying module logic of the application;

[0031] Figure 5 It is a schematic diagram of the pneumatic ash conveying module 1, 2 and 3 logic of the application;

[0032] Figure 6 It is a schematic diagram of the pneumatic ash conveying module 4 logic of the application;

[0033] Figure 7 It is a schematic diagram of the pneumatic ash conveying module 5 logic of the application;

[0034] Figure 8 It is a schematic diagram of the newly added pipeline ash conveying flow rate and time relationship of the application;

[0035] Figure 9This is a calculation data table for pipeline operation after the modification according to the present invention;

[0036] Figure 10 This invention adds a table showing the relationship between pipeline air density and pressure;

[0037] Figure 11 This is a simplified model of the new ash conveying logic of the present invention;

[0038] Figure 12 This is a graph showing the coal feed rate function of a certain unit in the ash conveying system of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] The ash conveying pipeline system was redesigned and its layout optimized.

[0042] like Figures 1-2 The schematic diagram of the existing pneumatic ash conveying unit system and the logic diagram of the existing pneumatic ash conveying module are shown. Under the high load operation of the unit, the ash conveying in the second electric field using the DN150 pipeline is blocked. The ash conveying time of the first electric field is occupied by the economizer and the second electric field, resulting in a high material level in the ash hopper. To solve the above two problems at the same time, it is necessary to increase the ash conveying capacity of the second electric field and ensure that the ash conveying time of the first electric field is sufficient.

[0043] Renovation plan such as Figure 3 The schematic diagram of the pneumatic ash conveying unit system of the present invention shown shows that: a new DN225 ash conveying pipeline is added, and the two DN125 pipelines in columns A and B of the economizer and the two DN150 pipelines in columns A and B of the second electric field are combined into one pipeline to convey ash to the ash silo;

[0044] 1. Analysis of the improvement in ash conveying in the electric field after modification

[0045] Analysis of the improvement in ash conveying in the primary electric field after the economizer and the secondary electric field were separated:

[0046] Before the upgrade: The economizer and the second electric field occupied the ash conveying time of the first electric field, which could not meet the requirements for normal operation of the unit;

[0047] After the upgrade: The electric field uses a separate ash conveying pipeline for ash conveying, which improves the conveying efficiency, ensures effective ash conveying time, and allows the unit to operate normally.

[0048] 2. The specific modifications to the plan are summarized as follows:

[0049] Pipeline one: an electric field one unit, pipe diameter is DN225 / DN250;

[0050] Pipeline two: an electric field two unit, pipe diameter is DN225 / DN250;

[0051] Pipeline three: an electric field three unit, pipe diameter is DN225 / DN250;

[0052] Pipeline four: three electric field A / B column, four electric field A / B column, five electric field A / B column ash conveying unit, pipe diameter is DN150;

[0053] New pipeline: two DN125 pipelines of economizer A column and B column are merged into one pipeline with two DN150 pipelines of the second electric field A column and B column to be transported to the ash storage, pipe diameter is DN125, DN150 / DN225.

[0054] After the transformation, there are five pipelines, four DN225 and one DN150, and the specific arrangement is as follows Figure 1 .

[0055] New pipeline pipe diameter

[0056] Known conditions:

[0057] (1) The average ash gas ratio of the system is taken as the guarantee value: 28 kg / kg; (2) The compressed air pressure of the air compressor is taken as: 0.7 Mpa; (3) The ash pipe internal conveying pressure is: 0.3 Mpa; (4) The flow rate at the beginning of the ash pipe is 4 m / s; (5) The flow rate at the end of the ash pipe is 12 m / s.

[0058] Analysis: Flow = cross-sectional area of pipeline x flow rate

[0059] Pipeline cross-sectional area = π x (pipe diameter / 2)2

[0060] As shown in the new pipeline ash flow rate and time relationship diagram: the flow unit is m 3 / h, the flow rate unit is m / s, and the pipe diameter unit is m. Figure 8

[0061] Average flow rate of ash pipe: (4+12) x 240 ÷ 2 ÷ 240 = 8 m / s;

[0062] The economizer circulates 3.37 times per hour, and each cycle is 3 minutes, and the second electric field circulates 1.81 times per hour, and each cycle is 4 minutes, so: 3.37 x 3 + 1.81 x 4 = 17.35 minutes;

[0063] Since the air enters the pipeline after the fly ash conveying pressure is 0.3 Mpa, the air pressure is calculated as 0.3 Mpa, and the air density is 3.5 kg / m 3 ; ​

[0064] The modified pipeline operation calculation data table is shown in Table 1: Figure 9

[0065] The total amount of ash transported by DN225 pipeline per hour is:

[0066] The flow rate of DN225 pipeline per minute is 3.14 x (0.225 / 2)2 x 8 x 60 = 19.08 m 3 / min;

[0067] The added pipeline air density and pressure relationship table is shown in Table 2: Figure 10

[0068] The ash-air ratio is 28, i.e. 28 kg of fly ash is transported per kg of air, which can be obtained:

[0069] The ash transportation amount per hour is 19.08 x 17.35 x 3.5 x 28 = 32.44 t / h; The ash amount per hour transported by the economizer and the second electric field is 10 + 16.93 = 26.93 t / h; The design value of DN225 is 32.44 t / h > 26.93 t / h, so DN225 meets the requirements of the ash transportation system.

[0070] 3. Ash transportation capacity of the added pipeline

[0071] Ash discharge data after adding the pipeline

[0072]

[0073] 4. Pipeline wear resistance

[0074] The added pipeline is made of interlocking ceramic, the outer pipe material is Q235, the wall thickness is 5 mm, the inner sleeve hardness is ≥HRC50, the ceramic is made of aluminum oxide material with a content of 95%, and the thickness is not less than 8 mm. With the ceramic wear amount of 0.4 mm / year, the maintenance cost can be effectively reduced, and the environment will not be affected by the wear of the pipeline.

[0075] Outer pipe performance:

[0076] Q235 Tensile strength Yield strength Hardness Index ≥ 410 MPa ≥ 245 MPa ≥ 130 HBS

[0077] Wear-resistant ceramic performance:

[0078]

[0079]

[0080] Mechanical properties of the pipeline:

[0081]

[0082] 5. The specific modification scheme is as follows​​

[0083] As Figures 5-7 the pneumatic ash conveying module logic diagram:

[0084] Pipeline one: electric dust removal - electric field A1 column, pipe diameter DN225 / DN250;

[0085] Pipeline two: electric dust removal - electric field A2 column, pipe diameter DN225 / DN250;

[0086] Pipeline three: electric dust removal - electric field A3 column, pipe diameter DN225 / DN250;

[0087] Pipeline four: electric dust removal three electric field A / B column, electric dust removal four electric field A / B column, electric dust removal five electric field A / B column ash conveying unit, pipe diameter DN150;

[0088] New pipeline: two DN125 pipelines of economizer A column and B column are merged with two DN150 pipelines of electric dust removal two electric field A column and B column into one pipeline to be conveyed to the ash storage, pipe diameter DN125, DN150 / DN225.

[0089] Example 2

[0090] 1. The DCS ash conveying logic re-integrates and allocates the ash conveying unit:

[0091] 13 independent ash conveying units, each unit has the following working steps:

[0092] Start → exhaust valve open → feed valve open → start feeding valve → level gauge alarm (or manually set feeding time) → feed valve close → exhaust valve close → discharge valve open → inlet valve open → start ash conveying → conveying pressure drop to set value → inlet valve close → discharge valve close → ash conveying ends (complete one cycle).

[0093] When the unit program control of the ash conveying system is started, the pressure conveying tank ash feeding adopts "level" control and "timing" control "level priority" control mode; during the ash feeding process of the pressure conveying tank, any pressure conveying tank appears "high" level or "timing" time, the ash conveying unit ends automatically and enters the next program of the ash conveying operation; the ash conveying system uses the same root pipe for each unit in the order and unit level, and is conveyed and operated one by one, and two or more units cannot be conveyed at the same time. When any unit is switched from manual mode to automatic mode, the ash conveying system is an ash automatic circulation system starting with feeding. The original ash conveying logic has thirteen ash conveying units in parallel relationship, without priority, and the ash conveying can be started when the condition of each ash conveying unit is met, but considering the ash conveying amount, the first electric field ash conveying unit should be selected, because the first electric field ash conveying share accounts for about 90% of the total ash conveying amount, and the conveying priority should be considered to ensure ash conveying priority and sufficient time.

[0094] 2. Ash conveying unit module optimization cycle principle: the three modules of ESP-1st field A1 column, ESP-1st field A2 column and ESP-1st field A3 column should be preferentially conveyed with a large proportion of ash conveying amount, and a smaller ash conveying time interval or continuous conveying should be adopted; the second is ESP-2nd field A column, ESP-2nd field B column, coal economizer A side and coal economizer B side; and the last is ESP-3rd field A column, ESP-3rd field B column, ESP-4th field A column, ESP-4th field B column, ESP-5th field A column and ESP-5th field B column.

[0095] In the ash conveying process, the ash amount and ash conveying parameters under the load of each stage are not constant, and have corresponding rules. The operation rules are combed and summarized. In the case of ensuring that the ash conveying system is not blocked, the unit coal supply amount is introduced to control the ash conveying unit feeding time, to ensure that the ash conveying cycle efficiency is reasonable, to convey as much ash as possible, to reduce the time interval of the cycle, to fully utilize the time for ash conveying, and to ensure the normal operation of the system.

[0096] 3. Ash conveying mode

[0097] 3.1 Start-up allowable conditions:

[0098] (1) The system pipeline connection is complete, the valve action is flexible, and there is no leakage;

[0099] (2) All air ducts must be cleaned by segmental purging;

[0100] (3) The ash conveying pipeline and the air pipeline must be subjected to pressure testing and leakage detection (the sealing test pressure of the ash path is 3-4 kg, and the sealing test pressure of the air path is 5-6 kg);

[0101] (4) Each ash hopper and each pressure conveying tank are dry and free of foreign matter and blockage;

[0102] (5) The opening degree of the unit manual regulating valve: the opening degree of the 1st field is 20%-30%; the opening degree of the 2nd field is 10%-20%; the opening degree of the 3rd, 4th and 5th fields is 5%-10%; and the opening degree of the coal economizer is 10%-15%;

[0103] (6) Check that there is no foreign matter in the coal economizer bin pump and the ash hopper;

[0104] (7) Parameter setting: coal economizer feeding time: 10-120 seconds; 1st field feeding time: 60-500 seconds; 2nd field feeding time: 60-500 seconds; 3rd field feeding time: 60-500 seconds; 4th field feeding time: 60-500 seconds; 5th field feeding time: 60-500 seconds; opening pressure of air supplement valve: all 0.2 MPa; ash conveying end pressure: 0.1 MPa (100 kPa); blockage pressure setting: 0.4 MPa; ash conveying overtime alarm time setting: 10 minutes;

[0105] (8) Instrument air supply is normal, pressure ≥ 0.5 MPa; each solenoid valve box must be in the open state, the pressure after the pressure regulating valve is adjusted to 0.55 MPa;

[0106] (9) The thermal switches, meters, alarms, protections and program controls are accurate and reliable, and have been put into operation; the feedback of all valves is normal; the material level switches of all pressure delivery tanks are working normally, and there is no alarm signal;

[0107] (10) All change-over switches in the valve box must be in program control state;

[0108] (11) All mechanical equipment has been oiled and the operation mode has been determined;

[0109] (12) All power equipment operation box indicator lights are working normally; all instruments of the power equipment are working normally and there is no abnormal phenomenon;

[0110] (13) The ash hopper and ash storage gasification fan and electric heater have been put into operation;

[0111] (14) The ash storage system equipment is normal, the bag-type dust collector is put into operation and is running normally (the blowback air inlet valve of the dust collector is opened and the manual pressure regulating valve at the air inlet end is set to 0.4 MPa; the negative pressure dust removal fan matched with the bag-type dust collector is put into operation and is running normally;

[0112] (15) The instrument air pipe connection of the ash storage system is complete, and there is no leakage phenomenon;

[0113] (16) The material level switch and continuous material level of the ash storage are running normally and there is no any abnormal phenomenon.

[0114] 3.2 Ash conveying explanation

[0115] The electrostatic precipitator ash conveying system is composed of 13 units. According to the historical operation investigation and the operation test after the ash conveying pipeline transformation, the control logic is designed in a modular manner, as shown in detail below:

[0116]

[0117]

[0118] Note:

[0119] (1) To ensure the pressure of the ash conveying main pipe, when the electrostatic precipitator one electric field A2 column is conveying ash, the electrostatic precipitator one electric field A3 column is in standby state; similarly, when the electrostatic precipitator one electric field A3 column is conveying ash, the electrostatic precipitator one electric field A2 column is in standby state.

[0120] (2) Economizer A column, economizer B column is a single gas source, can be with electric precipitator three electric field A column, electric precipitator three electric field B column, electric precipitator four electric field A column, electric precipitator four electric field B column, electric precipitator five electric field A column, electric precipitator five electric field B column in one of the ash conveying unit simultaneously ash conveying.

[0121] (3) Electric precipitator two electric field A column, electric precipitator two electric field B column, electric precipitator three electric field A column, electric precipitator three electric field B column, electric precipitator four electric field A column, electric precipitator four electric field B column, electric precipitator five electric field A column, electric precipitator five electric field B column eight ash conveying units according to the length of the waiting time after the material is dropped, do time sorting, determine the ash conveying priority (the unit with short material dropping time and less cycle interval time has high ash conveying frequency). The material dropping time of all units can be adjusted, and the cycle interval time can be adjusted to ensure the ash conveying frequency of each unit.

[0122] 4. Ash conveying module

[0123] Module 1 (electric precipitator one electric field A1 column)

[0124] Start-up permission conditions: (1) the gas pressure of the conveying gas source main pipe is greater than or equal to 0.2 MPa; (2) the pipeline-to-ash bin switch valve is opened (the valve to the coarse ash bin or the original ash bin is opened); (3) the program control permission state;

[0125] Ash conveying process:

[0126]

[0127] In the conveying process of step 6, if the pressure in the pipe is greater than or equal to 0.2 MPa, open the air supplement valve and open the assisted blowing, and if the pressure in the pipe is less than or equal to 0.17 MPa, close the air supplement valve.

[0128] Alarm: if the pressure in the pipe is greater than or equal to 0.4 MPa and lasts for 10 minutes, an alarm signal for pipe blockage is sent out.

[0129] Interlocking: (none).

[0130] Stop condition: the material discharge valve of electric precipitator one electric field A1 column is closed.

[0131] Module 2 (electric precipitator one electric field A2 column)

[0132] Start-up permission conditions:

[0133] (1) the gas pressure of the conveying gas source main pipe is greater than or equal to 0.2 MPa; (2) the pipeline-to-ash bin switch valve is opened (the valve to the coarse ash bin or the original ash bin is opened); (3) the material discharge valve of electric precipitator one electric field A3 column is in a closed state; (4) the program control permission state;

[0134] Ash conveying process:

[0135]

[0136] If the pressure in the pipe is ≥ 0.2 MPa, open the air supplement valve and open the air blowing, and if the pressure in the pipe is ≤ 0.17 MPa, close the air supplement valve.

[0137] Alarm: If the pressure in the pipe is ≥ 0.4 MPa and lasts for 10 minutes, send a pipe blocking alarm signal.

[0138] Interlock: (None).

[0139] Stopping condition: The electric precipitator 1, electric field A2, discharge valve is closed.

[0140] Module 3 (The electric precipitator 1, electric field A3)

[0141] Starting permission condition: (1) The pressure of the conveying gas source main pipe is ≥ 0.2 MPa; (2) The pipe to ash storage switching valve is opened (to the coarse ash storage or the original ash storage valve is opened); (3) The electric precipitator 1, electric field A2, discharge valve is closed; (4) The program control permission state.

[0142] Ash conveying process:

[0143]

[0144] If the pressure in the pipe is ≥ 0.2 MPa, open the air supplement valve and open the air blowing, and if the pressure in the pipe is ≤ 0.17 MPa, close the air supplement valve.

[0145] Alarm: If the pressure in the pipe is ≥ 0.4 MPa and lasts for 10 minutes, send a pipe blocking alarm signal.

[0146] Interlock: (None).

[0147] Stopping condition: The electric precipitator 1, electric field A3, discharge valve is closed.

[0148] Module 4 (The electric precipitator 2, electric field A, the electric precipitator 2, electric field B, economizer A, economizer B)

[0149] Starting permission condition of the electric precipitator 2, electric field A

[0150] (1) The pressure of the conveying gas source main pipe is ≥ 0.2 MPa; (2) The pipe to ash storage switching valve is opened (to the coarse ash storage or the original ash storage valve is opened); (3) The electric precipitator 2, electric field B, economizer A, economizer B is not conveying ash, and the discharge valve is closed; (4) The program control permission state.

[0151] Starting permission condition of the electric precipitator 2, electric field B

[0152] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to the coarse ash storage or original ash storage valve opening); (3) electrostatic precipitator two electric field A column, economizer A column, economizer B column has not been transported ash, discharge valve closed; (4) program control allowed state.

[0153] Economizer A column start allowed condition

[0154] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to the coarse ash storage or original ash storage valve opening); (3) electrostatic precipitator two electric field A column, electrostatic precipitator two electric field B column, economizer B column has not been transported ash, discharge valve closed; (4) program control allowed state.

[0155] Economizer B column start allowed condition

[0156] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to the coarse ash storage or original ash storage valve opening); (3) electrostatic precipitator two electric field A column, electrostatic precipitator two electric field B column, economizer A column has not been transported ash, discharge valve closed; (4) program control allowed state

[0157] Ash conveying process

[0158] Electrostatic precipitator two electric field A column ash conveying process:

[0159]

[0160] In the 6th step of the conveying process, if the pressure in the pipe is ≥ 0.2 MPa, then open the air supplement valve, open the air blowing, and if the pressure in the pipe is ≤ 0.17 MPa, then close the air supplement valve.

[0161] Electrostatic precipitator two electric field B column ash conveying process:

[0162]

[0163]

[0164] In the 6th step of the conveying process, if the pressure in the pipe is ≥ 0.2 MPa, then open the air supplement valve, open the air blowing, and if the pressure in the pipe is ≤ 0.17 MPa, then close the air supplement valve.

[0165] Economizer A column ash conveying process

[0166]

[0167] In the 6th step of the conveying process, if the pressure in the pipe is ≥ 0.2 MPa, then open the air supplement valve, open the air blowing, and if the pressure in the pipe is ≤ 0.17 MPa, then close the air supplement valve.

[0168] Economizer B column ash conveying process

[0169]

[0170] If the pressure in the pipe ≥ 0.2 MPa, open the air supplement valve and open the air blowing, and if the pressure in the pipe ≤ 0.17 MPa, close the air supplement valve.

[0171] Alarm: If the pressure in the pipe ≥ 0.4 MPa and lasts for 10 minutes, send a pipe blocking alarm signal.

[0172] Interlock: (None).

[0173] Stopping condition:

[0174] Electrostatic precipitator 2nd electric field A column ash conveying stopping condition: electrostatic precipitator 2nd electric field A column discharge valve closed;

[0175] Electrostatic precipitator 2nd electric field B column ash conveying stopping condition: electrostatic precipitator 2nd electric field B column discharge valve closed;

[0176] Economizer A column ash conveying stopping condition: economizer A column discharge valve closed;

[0177] Economizer B column ash conveying stopping condition: economizer B column discharge valve closed.

[0178] Module 5 (electrostatic precipitator 3rd electric field A column, electrostatic precipitator 3rd electric field B column, electrostatic precipitator 4th electric field A column, electrostatic precipitator 4th electric field B column, electrostatic precipitator 5th electric field A column, electrostatic precipitator 5th electric field B column)

[0179] Electrostatic precipitator 3rd electric field A column starting permission condition

[0180] (1) Conveying gas source main pipe pressure ≥ 0.2 MPa; (2) pipe to ash bin switch valve has been opened (to fine ash bin or original ash bin valve opened); (3) electrostatic precipitator 3rd electric field B column, electrostatic precipitator 4th electric field A column, electrostatic precipitator 4th electric field B column, electrostatic precipitator 5th electric field A column, electrostatic precipitator 5th electric field B column, discharge valve closed; (4) program control permission state

[0181] Electrostatic precipitator 3rd electric field B column starting permission condition

[0182] (1) Conveying gas source main pipe pressure ≥ 0.2 MPa; (2) pipe to ash bin switch valve has been opened (to fine ash bin or original ash bin valve opened); (3) electrostatic precipitator 3rd electric field A column, electrostatic precipitator 4th electric field A column, electrostatic precipitator 4th electric field B column, electrostatic precipitator 5th electric field A column, electrostatic precipitator 5th electric field B column, discharge valve closed; (4) program control permission state

[0183] Electrostatic precipitator 4th electric field A column starting permission condition

[0184] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to fine ash storage or original ash storage valve opening); (3) electrostatic precipitator three electric field A column, electrostatic precipitator three electric field B column, electrostatic precipitator four electric field B column, electrostatic precipitator five electric field A column, electrostatic precipitator five electric field B column, discharge valve closed; (4) program control allowed state

[0185] Electrostatic precipitator four electric field B column start-up allowed condition

[0186] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to fine ash storage or original ash storage valve opening); (3) electrostatic precipitator three electric field A column, electrostatic precipitator three electric field B column, electrostatic precipitator four electric field A column, electrostatic precipitator five electric field A column, electrostatic precipitator five electric field B column, discharge valve closed; (4) program control allowed state.

[0187] Electrostatic precipitator five electric field A column start-up allowed condition

[0188] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to fine ash storage or original ash storage valve opening); (3) electrostatic precipitator three electric field A column, electrostatic precipitator three electric field B column, electrostatic precipitator four electric field A column, electrostatic precipitator four electric field B column, electrostatic precipitator five electric field B column, discharge valve closed; (4) program control allowed state

[0189] Electrostatic precipitator five electric field B column start-up allowed condition

[0190] (1) conveying gas source main pipe gas pressure ≥ 0.2 MPa; (2) pipeline to ash storage switching valve has been opened (to fine ash storage or original ash storage valve opening); (3) electrostatic precipitator three electric field A column, electrostatic precipitator three electric field B column, electrostatic precipitator four electric field A column, electrostatic precipitator four electric field B column, electrostatic precipitator five electric field A column, discharge valve closed; (4) program control allowed state

[0191] Ash conveying process

[0192] Electrostatic precipitator three electric field A column ash conveying process:

[0193]

[0194] In the 6th step conveying process, if the pipe pressure ≥ 0.2 MPa, then open the air supplement valve, open the air blowing, and the pipe pressure ≤ 0.17 MPa, then close the air supplement valve.

[0195] Electrostatic precipitator three electric field A column ash conveying process

[0196]

[0197]

[0198] Step 6, if the pressure in the pipe ≥ 0.2 MPa, then open the air valve, open the blow, the pressure in the pipe ≤ 0.17 MPa, then close the air valve.

[0199] Electrostatic precipitator four electric field A column ash conveying process

[0200]

[0201] Step 6, if the pressure in the pipe ≥ 0.2 MPa, then open the air valve, open the blow, the pressure in the pipe ≤ 0.17 MPa, then close the air valve.

[0202] Electrostatic precipitator four electric field B column ash conveying process

[0203]

[0204] Step 6, if the pressure in the pipe ≥ 0.2 MPa, then open the air valve, open the blow, the pressure in the pipe ≤ 0.17 MPa, then close the air valve.

[0205] Electrostatic precipitator five electric field A column ash conveying process

[0206]

[0207]

[0208] Step 6, if the pressure in the pipe ≥ 0.2 MPa, then open the air valve, open the blow, the pressure in the pipe ≤ 0.17 MPa, then close the air valve.

[0209] Electrostatic precipitator five electric field B column ash conveying process

[0210]

[0211] Step 6, if the pressure in the pipe ≥ 0.2 MPa, then open the air valve, open the blow, the pressure in the pipe ≤ 0.17 MPa, then close the air valve.

[0212] Alarm: if the pressure in the pipe ≥ 0.4 MPa, and lasts for 10 min, send a pipe blockage alarm signal;

[0213] Interlock: (none);

[0214] Stop condition:

[0215] Electrostatic precipitator three electric field A column ash conveying stop condition: electrostatic precipitator three electric field A column discharge valve is closed;

[0216] Three electric field B column ash conveying stop condition: electrostatic precipitator three electric field B column discharge valve is closed;

[0217] Electrostatic precipitator four electric field A column ash conveying stop condition: electrostatic precipitator four electric field A column discharge valve is closed;

[0218] Electrostatic precipitator four electric field B column ash conveying stop condition: electrostatic precipitator four electric field B column discharge valve is closed;

[0219] Electrostatic precipitator five electric field A column ash conveying stop condition: electrostatic precipitator five electric field A column discharge valve is closed;

[0220] Electrostatic precipitator five electric field B column ash conveying stop condition: electrostatic precipitator five electric field B column discharge valve is closed.

[0221] 5. Each ash conveying module cycle

[0222] Each ash conveying unit submodule is logically sorted in fixed discharging time, ash conveying time and ash conveying sequence to form a semi-automatic ash conveying control logic.

[0223] New ash conveying logic sorting table:

[0224]

[0225]

[0226] New ash conveying logic simplified model (such as Figure 11 ):

[0227] Description: Each step sequence is simultaneous ash conveying of two ash conveying units, and 10 minutes is a basic cycle; Electrostatic precipitator one electric field A1, electrostatic precipitator one electric field A2, electrostatic precipitator one electric field A3, electrostatic precipitator two electric field A column and electrostatic precipitator two electric field B column are cycled 6 times in 1 hour, and electrostatic precipitator three electric field A column and B column, electrostatic precipitator four electric field A column and B column, electrostatic precipitator five electric field A column and B column are each cycled once; At the same time, the A and B side air source distribution situation is taken into account to avoid too low compressed air main pipe force affecting the ash conveying effect. The coal amount signal will be introduced in the later stage to participate in the automatic control of the ash hopper feeding time of each step sequence, according to the coal amount and the given coal ash content value, to participate in the automatic operation control of the system, and to realize the automatic control of the ash conveying to track the coal amount and coal quality.

[0228] New ash conveying logic interlocking relationship: when step sequence 1 is executed, electrostatic precipitator one electric field A1 column and electrostatic precipitator one electric field A3 column two pipelines can simultaneously convey ash; When step sequence 2 is executed, electrostatic precipitator one electric field A2 column and electrostatic precipitator two electric field A column can simultaneously convey ash; When step sequence 3 is executed, electrostatic precipitator two electric field B column and one of electrostatic precipitator three electric field A column, electrostatic precipitator three electric field B column, electrostatic precipitator four electric field A column, electrostatic precipitator four electric field B column, electrostatic precipitator five electric field A column and electrostatic precipitator five electric field B column simultaneously convey ash (when the previous step sequence is executed, the latter step sequence discharges and waits). The economizer unit is independently cycled, and the economizer A side and the economizer B side alternate ash conveying, and the start permission condition is increased: both electrostatic precipitator two electric field A column and B column do not convey ash, and the discharge valve closing signal is taken out.

[0229] New ash conveying logic table of each ash conveying unit cycle time per hour:

[0230]

[0231] New ash conveying logic table of each ash conveying unit reference set feeding time:

[0232]

[0233] Example 3

[0234] Coal quantity and quality comprehensive control DCS automatic ash conveying logic device

[0235] At present, the domestic coal market price is running at a high level, and the coal-fired power generation enterprises have huge pressure to ensure supply. In order to reduce the cost of power generation, a large amount of mixed coal deviating from the design coal is burned, especially low calorific value, high ash content, and high and low ash melting point coal; According to the actual mixed burning situation of the owner of a power plant and future demands, when designing the DCS coal quantity control automatic ash conveying system, the influence of ash content on the operation of the ash conveying system is fully considered. The ash content data of the mixed coal quantity is introduced as an important fixed value parameter of the correction coal quantity and ash conveying system control function, which can fully correct the function relationship to adapt to the mixed burning of different coals and realize more accurate tracking of the change of the coal quantity signal. At the same time, the historical ash conveying system operation data, coal quantity, and unit electric load data of the power plant are collected and analyzed, and the linear function relationship between the coal quantity and the ash conveying system unit feeding time is mapped.

[0236] Table of typical load data of unmodified ash conveying system operation

[0237]

[0238]

[0239] Ash conveying system data table of a unit

[0240]

[0241] The ash conveying system function curve of a unit tracking coal quantity is as shown in Figure 12

[0242] y=kx+b

[0243] y-ash conveying unit feeding valve opening time;

[0244] x-average value of coal quantity in a certain time period of the unit;

[0245] k-positive relationship number of coal quantity and ash falling time;

[0246] b-correction linear relationship constant, ash conveying initial pressure, end pressure, air valve delay, exhaust and circulation time; ​

[0247] Parameter setting: all of the opening pressure of the air supplement valve is 0.2-0.25MPa; the end pressure of the ash conveying is 0.07Mpa (70KP)-0.13Mpa (130KP); the pipe blocking pressure is set as 0.4Mpa.

[0248] The function is connected to the ash conveying DCS control system, realizes automatic tracking of the change of the coal supply amount by the change of the ash conveying system, and makes the circulating efficiency of the ash conveying system optimal.

[0249] In summary, the present application independently arranges the electric dust removal electric field A1, A2 and A3 units, reasonably distributes the electric dust removal electric field A / B and the ash conveying pipeline of the economizer A / B, solves the mutual influence and exclusion in the ash conveying process, reduces the ash conveying frequency, and easily causes the pipe blocking or high ash phenomenon. In addition, the ash conveying unit is modularized and simply and efficiently circulated, the ash conveying frequency and efficiency of the main ash conveying unit are improved, the ash conveying sequence of each ash conveying unit is reasonably distributed, and the overall efficiency of the ash conveying system is improved. Meanwhile, the unit coal supply amount signal is introduced and participates in the automatic control DCS logic sequence of the ash conveying system, realizes automatic tracking of the change of the unit load and the coal supply amount (including the coal quality), reasonably distributes the ash conveying sequence, frequency and time of each ash conveying unit, greatly reduces the human intervention in the ash conveying, and automatically removes the fault unit when the individual ash conveying unit fails, without affecting the automatic tracking of the unit load operation of the other ash conveying units.

[0250] The present application realizes the modularization and simplification of the ash conveying system, automatically tracks the unit load and the coal supply amount signal, and can be adjusted and corrected according to the coal quality. When the individual ash conveying unit fails, the fault unit is automatically removed, without affecting the automatic tracking of the unit load operation of the other ash conveying units, realizes the automatic operation, and greatly reduces the operation personnel intervention operation.

[0251] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A DCS automatic ash conveying logic system, characterized in that, The system includes ash conveying units, which are divided into 13 ash conveying units, namely: Electrostatic precipitator, electric field A1 column, electrostatic precipitator, electric field A2 column, electrostatic precipitator, electric field A3 column; Economizer A side, economizer B side; Electrostatic precipitator, second electric field, column A; Electrostatic precipitator, second electric field, column B; Column A of the three electric fields of the electrostatic precipitator; Column B of the three electric fields of the electrostatic precipitator; Electrostatic precipitator four electric fields, column A; Electrostatic precipitator four electric fields, column B; Electrostatic precipitator five-field column A, electrostatic precipitator five-field column B; Among them, the first electric field A1 column of the electrostatic precipitator is connected to the first electric field A1 column raw ash silo and the first electric field A1 column coarse ash silo through pipelines; the first electric field A2 column of the electrostatic precipitator is connected to the first electric field A2 column raw ash silo and the first electric field A2 column coarse ash silo through pipelines; the first electric field A3 column of the electrostatic precipitator is connected to the first electric field A3 column raw ash silo and the first electric field A3 column coarse ash silo through pipelines. The second electric field A column, the second electric field B column, the economizer A side, and the economizer B side are respectively connected to the newly added original ash silo and the newly added coarse ash silo via pipelines; The three electric fields A column, the three electric fields B column, the four electric fields A column, the four electric fields B column, the five electric fields A column, and the five electric fields B column of the electrostatic precipitator are respectively connected to the ash removal silo through pipelines; Based on historical operational data and operational tests after the ash conveying pipeline modification, the control logic was designed in a modular fashion. The 13 units of the ash conveying unit system were divided into 5 sub-modules: the three modules with the largest ash conveying volume (e.g., EDF Field A1, EDF Field A2, and EDF Field A3) were prioritized for conveying ash; followed by EDF Field A, EDF Field B, the economizer A side, and the economizer B side; and finally, EDF Field A, EDF Field B, EDF Field A, EDF Field B, EDF Field A, EDF Field B, EDF Field A, and EDF Field B. Each of the aforementioned ash conveying unit system sub-modules is logically sorted according to a fixed material dropping time, ash conveying time, and ash conveying sequence to form a semi-automatic ash conveying control logic; based on the coal quantity and the given coal type ash content value, it participates in the automatic operation control of the system to realize automatic ash conveying control tracking of coal quantity and coal quality; The power plant’s historical data on ash conveying unit system operation, coal feed rate, and unit electrical load were collected and analyzed to map a linear function relationship between coal feed rate and material delivery time of each unit in the ash conveying unit system. y=kx+b y - Opening time of the feed valve in the ash conveying unit system; x - Average coal feed rate of the unit within a certain time period; k - the positive correlation coefficient between coal feed rate and ash collection time; b - Correction constant for linear relationship; Integrate this function into the ash conveying DCS control system to enable the ash conveying unit system to automatically track changes in the coal feed rate.

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