阅读说明：本技术 降低双进双出磨煤机启停对脱硝系统扰动的方法及系统 (Method and system for reducing disturbance of start and stop of double-inlet and double-outlet coal mill on denitration system ) 是由 王景华 宋益纯 戚兴坤 赵建新 何刚 赵培山 韩敏 王纪东 孙华伟 于 2020-03-30 设计创作，主要内容包括：本公开提供了一种降低双进双出磨煤机启停对脱硝系统扰动的方法及系统,属于燃煤电厂自动控制技术领域,通过修正磨煤机煤位变化对容量风量的影响,提高了容量风量的测量精度,使磨煤机启停期间容量风量更能代表真实的燃料量,有利于机组燃烧系统的稳定运行、减少烟气中氮氧化物浓度的波动；通过合理控制双进双出磨煤机启停时容量风量、二次风量的变化范围和变化速率,降低了助燃风量和燃料量波动对燃烧工况的扰动强度；通过合理控制容量风量和二次风量的配比,实现了助燃风与燃料量的良好匹配,减少了烟气中氧量的大幅波动,使烟气中生成的氮氧化物浓度波动范围小、变化平缓,有利于脱硝系统的稳定运行。(The utility model provides a method and a system for reducing the disturbance of the start and stop of a double-inlet and double-outlet coal mill to a denitration system, which belongs to the technical field of the automatic control of coal-fired power plants, and improves the measurement precision of the capacity air volume by correcting the influence of the coal level change of the coal mill on the capacity air volume, so that the capacity air volume can represent the real fuel quantity during the start and stop of the coal mill, thereby being beneficial to the stable operation of a unit combustion system and reducing the fluctuation of the concentration of nitrogen oxides in flue gas; the disturbance intensity of combustion-supporting air quantity and fuel quantity fluctuation to the combustion working condition is reduced by reasonably controlling the variation range and the variation rate of the capacity air quantity and the secondary air quantity when the double-inlet and double-outlet coal mill is started and stopped; by reasonably controlling the ratio of the volume air volume and the secondary air volume, good matching of combustion-supporting air and fuel volume is realized, great fluctuation of oxygen amount in flue gas is reduced, the fluctuation range of concentration of nitrogen oxides generated in the flue gas is small, the change is smooth, and the stable operation of a denitration system is facilitated.)

1. A method for reducing disturbance of start and stop of a double-inlet and double-outlet coal mill on a denitration system is characterized by comprising the following steps:

obtaining the corrected volume air quantity of the coal level according to the corrected coal level of the double-inlet and double-outlet coal mill;

obtaining a ratio function of the combustion-supporting air volume and the volume air volume corrected by the coal level according to the volume air volume corrected by the coal level;

when the double-inlet double-outlet coal mill and the corresponding coal feeder are started, controlling the coal quantity of the coal feeder according to the maximum initial coal feeding quantity and the increasing rate of the preset coal feeder, controlling the capacity air quantity according to the maximum initial value and the increasing and decreasing rate of the capacity air quantity, and controlling the combustion-supporting air quantity according to the maximum initial value and the increasing and decreasing rate of the combustion-supporting air quantity, and the ratio function of the combustion-supporting air quantity and the corrected capacity air quantity of the coal level until the coal mill reaches the range of the preset coal level;

before the double-inlet and double-outlet coal mill stops, when the coal level is reduced to be below the lower limit of the normal range, the capacity air volume and the combustion-supporting air volume are respectively controlled according to preset capacity air volume increasing and decreasing rate, combustion-supporting air volume increasing and decreasing rate, and the proportioning function of the combustion-supporting air volume and the capacity air volume after the coal level is corrected until the coal mill stops operating.

2. The method for reducing the disturbance of the start-stop of the double-inlet and double-outlet coal mill on the denitration system as claimed in claim 1, wherein the volume air volume after the coal level correction is specifically the product of a volume air volume correction function taking the coal level as a variable and the air volume measured by the volume air volume measuring device.

3. The method for reducing the disturbance of the start-stop of the double-inlet and double-outlet coal pulverizer on the denitration system as claimed in claim 2, wherein a capacity air volume correction function taking the coal level as a variable is a piecewise function, and the specific obtaining method comprises the following steps:

when the coal mill and the corresponding coal feeder are started, the capacity air volume is controlled to be kept unchanged at the average value of normal operation, and the coal level is controlled to be at the average value of normal operation, the average value of the active load of the unit is obtained; the coal level of the coal mill is controlled to be higher or lower than the average value of the coal level in normal operation by a fixed value, the active load value of the corresponding coal level is obtained after the active load of the standby group is stable, and the capacity air volume correction function is the ratio of the corresponding active load value to the current active load value after the active load value is higher or lower by a fixed value.

4. The method for reducing the disturbance of the start-stop of the double-inlet and double-outlet coal pulverizer on the denitration system as claimed in claim 2, wherein a capacity air volume correction function taking the coal level as a variable is a piecewise function, and the specific obtaining method comprises the following steps:

when the coal mill and the corresponding coal feeder are started, the volume air volume is controlled to be constant in the average value of normal operation, and the coal level is controlled to be the average value of normal operation, the average coal powder concentration in the volume air pipe is obtained, the coal level of the coal mill is controlled to be a fixed value higher or lower than the average value of the coal level of normal operation, the coal level is changed, the average coal powder concentration in the volume air pipe is detected, the coal powder concentration under the corresponding coal level is obtained, and the volume air volume correction function is the ratio of the average coal powder concentration corresponding to the high or low fixed value to the current average coal powder concentration.

5. The method for reducing the disturbance of the start-stop of the double-inlet and double-outlet coal mill on the denitration system as claimed in claim 1, wherein the specific obtaining method of the proportion function of the combustion-supporting air volume and the volume air volume after the coal level correction is as follows:

when the coal mill and the corresponding coal feeder are started, the volume air quantity is controlled to be unchanged at the average value of normal operation, and the coal level is controlled to be the average value of normal operation, the combustion-supporting air quantity of the coal mill is adjusted, so that the oxygen content in the flue gas is kept at the normal operation value, and the combustion-supporting air quantity value of the coal mill and the volume air quantity value corrected by the coal level at the moment are obtained;

when the volume air quantity of the coal mill is increased to the maximum value allowed by normal operation and the coal grinding position is increased to the maximum value allowed by normal operation, adjusting the combustion-supporting air quantity to keep the oxygen content in the flue gas at the normal operation value, and obtaining the combustion-supporting air quantity value of the coal mill and the volume air quantity value corrected by the coal position at the moment;

when the coal level of the coal mill is reduced to a position below the average value of normal operation and the volume air volume is reduced to a value below the average value of normal operation, adjusting the combustion-supporting air volume to keep the oxygen content in the flue gas at the normal operation value, and obtaining the combustion-supporting air volume value of the coal mill and the volume air volume value corrected by the coal level at the moment;

and repeating the steps until the coal level of the coal mill is reduced to the minimum, the capacity air quantity is reduced to the minimum allowable value, and the combustion-supporting air quantity is reduced to the minimum allowable value, so as to obtain the proportion function relationship between the combustion-supporting air quantity and the capacity air quantity after the coal level correction.

6. The method for reducing the disturbance of the start-stop of the double-inlet and double-outlet coal mill on the denitration system as claimed in claim 1, wherein after the double-inlet and double-outlet coal mill is stopped, the combustion-supporting air volume is adjusted to the maximum initial value of the combustion-supporting air volume according to the set increase and decrease rate of the combustion-supporting air volume.

7. The utility model provides a system for it stops denitration system disturbance to reduce two advance double-outlet coal pulverizer to open, which characterized in that includes:

the volume air quantity obtaining module after the coal level correction is configured to: obtaining the corrected volume air quantity of the coal level according to the corrected coal level of the double-inlet and double-outlet coal mill;

a proportioning function acquisition module configured to: obtaining a ratio function of the combustion-supporting air volume and the volume air volume corrected by the coal level according to the volume air volume corrected by the coal level;

a control module configured to: when the double-inlet double-outlet coal mill and the corresponding coal feeder are started, controlling the coal quantity of the coal feeder according to the maximum initial coal feeding quantity and the increasing rate of the preset coal feeder, controlling the capacity air quantity according to the maximum initial value and the increasing and decreasing rate of the capacity air quantity, and controlling the combustion-supporting air quantity according to the maximum initial value and the increasing and decreasing rate of the combustion-supporting air quantity, and the ratio function of the combustion-supporting air quantity and the corrected capacity air quantity of the coal level until the coal mill reaches the range of the preset coal level;

before the double-inlet and double-outlet coal mill stops, when the coal level is reduced to be below the lower limit of the normal range, the capacity air volume and the combustion-supporting air volume are respectively controlled according to preset capacity air volume increasing and decreasing rate, combustion-supporting air volume increasing and decreasing rate, and the proportioning function of the combustion-supporting air volume and the capacity air volume after the coal level is corrected until the coal mill stops operating.

8. The system for reducing the disturbance of the start-stop of the double-inlet double-outlet coal mill on the denitration system as recited in claim 7, wherein said control module further comprises:

a capacity air volume correction calculation module configured to: calculating and eliminating the influence of the coal level change of the double-inlet and double-outlet coal mill on the measurement precision of the volumetric air quantity;

a maximum initial coal feed amount setting module of a coal feeder configured to: setting the maximum initial coal feeding amount for starting the coal feeder;

a coal feeder coal feed increase rate setting module configured to: setting the highest rate when the coal amount of the coal feeder is increased;

a capacity air volume maximum initial value setting module configured to: setting a maximum initial value of the volume air quantity when the coal mill is started;

a capacity air volume rate setting module configured to: setting the maximum increase and decrease rate of the volume air volume;

the combustion-supporting air volume maximum initial value setting module is configured to: setting a maximum initial value of combustion-supporting air quantity when a coal feeder is started;

the combustion-supporting air volume rate setting module is configured to: setting the maximum increase and decrease rate of combustion-supporting air volume;

the combustion-supporting air volume and corrected volume air volume ratio function setting module is configured to: and setting a matching function relation between the combustion-supporting air quantity and the volume air quantity after the coal level correction.

9. A medium having a program stored thereon, wherein the program when executed by a processor implements the steps in the method of reducing disturbances to a denitration system from start-stop of a two-in-two-out coal mill of any of claims 1 to 6.

10. An electronic device comprising a memory, a processor and a program stored on the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method for reducing disturbance of start-stop of a two-in-two-out coal pulverizer to a denitration system according to any one of claims 1 to 6.

Technical Field

The disclosure relates to the technical field of automatic control of coal-fired power plants, in particular to a method and a system for reducing disturbance of starting and stopping of a double-inlet and double-outlet coal mill on a denitration system.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The unit of the direct-fired pulverizing system adopting the double-inlet and double-outlet coal mill needs to be frequently started and stopped when the unit operates under a large-range variable load, so that the fuel quantity entering a hearth is changed. During the start and stop of the coal mill, due to the fact that the fluctuation range of the capacity air volume (or called primary air volume carrying coal dust) and the combustion-supporting air volume (or called secondary air volume) entering a hearth is large and the fluctuation speed is high, and meanwhile, the proportion of the capacity air volume and the combustion-supporting air volume is not proper, coal dust entering the hearth is subjected to oxygen-enriched combustion or oxygen-deficient combustion, the content of nitrogen oxides in smoke is changed rapidly, and great disturbance is formed on the operation of a denitration system; meanwhile, because the existing extraction-type flue gas nitrogen oxide detection instrument has long measurement lag time (about 2 minutes), the nitrogen oxide at the outlet of the denitration reactor is difficult to be controlled in an automatic mode, and operators often need to perform manual intervention, so that the short-time ultra-standard emission of the nitrogen oxide or excessive ammonia spraying can easily cause the increase of ammonia escape amount, and the economic and stable operation of a denitration system is influenced.

Disclosure of Invention

In order to solve the defects of the prior art, the first aspect of the disclosure provides a method for reducing the disturbance of the start and stop of the double-inlet and double-outlet coal mill on a denitration system, the second aspect of the disclosure provides a system for reducing the disturbance of the start and stop of the double-inlet and double-outlet coal mill on the denitration system, the matching with the fuel quantity is realized by reasonably controlling the change of the combustion-supporting air quantity when the double-inlet and double-outlet coal mill is started and stopped, and the large fluctuation of nitrogen oxides in flue gas is reduced.

In order to achieve the purpose, the following technical scheme is adopted in the disclosure:

the first aspect of the disclosure provides a method for reducing disturbance of starting and stopping of a double-inlet and double-outlet coal mill on a denitration system.

A method for reducing disturbance of start and stop of a double-inlet and double-outlet coal mill on a denitration system comprises the following steps:

obtaining the corrected volume air quantity of the coal level according to the corrected coal level of the double-inlet and double-outlet coal mill;

obtaining a ratio function of the combustion-supporting air volume and the volume air volume corrected by the coal level according to the volume air volume corrected by the coal level;

when the double-inlet double-outlet coal mill and the corresponding coal feeder are started, controlling the coal quantity of the coal feeder according to the maximum initial coal feeding quantity and the increasing rate of the preset coal feeder, controlling the capacity air quantity according to the maximum initial value and the increasing and decreasing rate of the capacity air quantity, and controlling the combustion-supporting air quantity according to the maximum initial value and the increasing and decreasing rate of the combustion-supporting air quantity, and the ratio function of the combustion-supporting air quantity and the corrected capacity air quantity of the coal level until the coal mill reaches the range of the preset coal level;

before the double-inlet and double-outlet coal mill stops, when the coal level is reduced to be below the lower limit of the normal range, the capacity air volume and the combustion-supporting air volume are respectively controlled according to preset capacity air volume increasing and decreasing rate, combustion-supporting air volume increasing and decreasing rate, and the proportioning function of the combustion-supporting air volume and the capacity air volume after the coal level is corrected until the coal mill stops operating.

The second aspect of the disclosure provides a system for reducing disturbance of start and stop of a double-inlet and double-outlet coal mill to a denitration system.

The utility model provides a system for it stops to denitration system disturbance to reduce two advance double-outlet coal pulverizer to open includes:

the volume air quantity obtaining module after the coal level correction is configured to: obtaining the corrected volume air quantity of the coal level according to the corrected coal level of the double-inlet and double-outlet coal mill;

a proportioning function acquisition module configured to: obtaining a ratio function of the combustion-supporting air volume and the volume air volume corrected by the coal level according to the volume air volume corrected by the coal level;

a control module configured to: when the double-inlet double-outlet coal mill and the corresponding coal feeder are started, controlling the coal quantity of the coal feeder according to the maximum initial coal feeding quantity and the increasing rate of the preset coal feeder, controlling the capacity air quantity according to the maximum initial value and the increasing and decreasing rate of the capacity air quantity, and controlling the combustion-supporting air quantity according to the maximum initial value and the increasing and decreasing rate of the combustion-supporting air quantity, and the ratio function of the combustion-supporting air quantity and the corrected capacity air quantity of the coal level until the coal mill reaches the range of the preset coal level;

before the double-inlet and double-outlet coal mill stops, when the coal level is reduced to be below the lower limit of the normal range, the capacity air volume and the combustion-supporting air volume are respectively controlled according to preset capacity air volume increasing and decreasing rate, combustion-supporting air volume increasing and decreasing rate, and the proportioning function of the combustion-supporting air volume and the capacity air volume after the coal level is corrected until the coal mill stops operating.

A third aspect of the present disclosure provides a medium having a program stored thereon, where the program, when executed by a processor, implements the steps in the method for reducing disturbance of start-stop of a two-in two-out coal mill on a denitration system according to the first aspect of the present disclosure.

A fourth aspect of the present disclosure provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, where the processor executes the program to implement the steps in the method for reducing disturbance of start and stop of a two-in and two-out coal pulverizer on a denitration system according to the first aspect of the present disclosure.

Compared with the prior art, the beneficial effect of this disclosure is:

1. according to the method, the system, the medium and the electronic equipment, the influence of the coal level of the coal mill on the measurement accuracy of the volumetric air quantity is eliminated through the acquired volumetric air quantity after the coal level correction and the proportion function of the combustion-supporting air quantity and the volumetric air quantity after the coal level correction, so that the volumetric air quantity can represent the real fuel quantity during the start-stop period of the coal mill, the stable operation of a unit combustion system is facilitated, and the fluctuation of the concentration of nitrogen oxides in smoke is reduced.

2. According to the method, the system, the medium and the electronic equipment, disturbance intensity on combustion working conditions is reduced by reasonably controlling the variation range and the variation rate of the capacity air quantity and the combustion-supporting air quantity when the double-inlet double-outlet coal mill is started and stopped, good matching of the combustion-supporting air and the fuel quantity is realized by reasonably controlling the ratio of the capacity air quantity and the combustion-supporting air quantity, large fluctuation of oxygen quantity in flue gas is reduced, the concentration fluctuation range of nitrogen oxides generated in the flue gas is small, the variation is smooth, and stable operation of a denitration system is facilitated.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

Fig. 1 is a logic diagram of automatic combustion-supporting air volume setting and output control for the left side and the right side of the mill a provided in embodiment 1 of the present disclosure.

Fig. 2 is a logic diagram of a1 coal feeder coal quantity setting output control provided in embodiment 1 of the present disclosure.

Fig. 3 is a logic diagram of output control for setting capacity and air volume at left side of mill a provided in embodiment 1 of the present disclosure.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

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 disclosure. 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 embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.