CN111495129B - Override control method for solving sudden rising of NOx concentration in denitration ammonia injection system - Google Patents
Override control method for solving sudden rising of NOx concentration in denitration ammonia injection system Download PDFInfo
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- CN111495129B CN111495129B CN202010335418.3A CN202010335418A CN111495129B CN 111495129 B CN111495129 B CN 111495129B CN 202010335418 A CN202010335418 A CN 202010335418A CN 111495129 B CN111495129 B CN 111495129B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/346—Controlling the process
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/30—Controlling by gas-analysis apparatus
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/76—Gas phase processes, e.g. by using aerosols
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/79—Injecting reactants
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
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Abstract
The invention relates to an override control method for solving sudden rising of NOx concentration in a denitration ammonia injection system. The method comprises the following steps: under the special condition that the unit load rises and the concentration of the NOx at an outlet rises simultaneously, when the parameters of the existing NOx and the unit load exceed the original data and reach a certain amplitude value within a certain time, a primary override feedforward is triggered to quickly open an ammonia injection valve so that the ammonia injection flow rate meets the requirement of the load change working condition and does not exceed the smoke emission limit value; the unit load rise and outlet NOx concentration change criteria are further increased, a second level override feedforward is triggered when the rate of rise of the unit load and the rate of change of rise of the outlet NOx concentration reach a second level criteria, and a first level override feedforward continuation is triggered to inhibit further increases in the outlet NOx concentration. The invention can effectively ensure that the concentration of the nitrogen oxide at the outlet suddenly rises under special working conditions to be timely controlled by the ammonia injection flow feedforward, and improve the stability of the automatic ammonia injection control system.
Description
Technical Field
The invention relates to the technical field of ammonia injection, in particular to an override control method for solving the problem of sudden rising of NOx concentration in a denitration ammonia injection system.
Background
At present, with the implementation of environmental protection policies in the traditional thermal power industry, the standard of nitrogen oxides in flue gas discharged by a power plant reaches 50 milligrams per cubic meter, the concentration of nitrogen oxides (namely NOx) at a flue gas discharge outlet is easy to fluctuate and exceed the discharge standard under various special working conditions in the power plant, and field control personnel often need to spray excessive ammonia to achieve a good control effect; meanwhile, the development of intelligent technology changes the requirements of system engineering technology all the time: in order to save labor cost, realize the automation task in the flue gas denitration process of the power plant, ensure that nitrogen oxides do not exceed the existing flue gas emission standard under various working conditions, and override control and optimization play an indispensable role in the automatic ammonia spraying process.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an override control method for solving the sudden rising of the concentration of NOx in a denitration ammonia injection system, which effectively ensures that the sudden rising of the concentration of the outlet nitrogen oxide can be timely controlled by ammonia injection flow feedforward when special working conditions occur, and improves the stability of the automatic ammonia injection control system.
Specifically, among the current ammonia technology of spouting, traditional PID logical control is used mostly in the ammonia control is spouted in the denitration, because signal transmission often has the time lag in the system, spouts the ammonia volume and hardly makes timely accurate reaction along with existing operating mode change data.
The invention aims to complete feedback control and simultaneously use double-stage override to ensure that the smoke emission does not exceed the national smoke emission standard based on the existing PID logic control system.
Technical objects that can be achieved by the present invention are not limited to what has been particularly described above, and other technical objects that are not described herein will be more clearly understood by those skilled in the art from the following detailed description.
The technical scheme for solving the technical problems is as follows:
according to a first aspect of the present disclosure, the present invention provides an override control method for solving a sudden increase in NOx concentration in a denitration ammonia injection system, the method comprising:
under the special condition that the unit load rises and the concentration of the NOx at an outlet rises simultaneously, when the parameters of the existing NOx and the unit load exceed the original data and reach a certain amplitude value within a certain time, a primary override feedforward is triggered to quickly open an ammonia injection valve so that the ammonia injection flow can meet the requirement of the load change working condition and does not exceed the smoke emission limit value; and
the unit load rise and outlet NOx concentration change criteria are further increased, a second level override feedforward is triggered when the rate of rise of the unit load and the rate of change of rise of the outlet NOx concentration reach a second level criteria, and a first level override feedforward continuation is triggered to inhibit further increases in the outlet NOx concentration.
Optionally, in the method as described above, an inertia element follows the primary and secondary override feedforward.
Optionally, in the method as described above, the inertial element is timed
The above-described embodiments are only some of the embodiments of the present invention, and those skilled in the art can derive and understand various embodiments including technical features of the present invention from the following detailed description of the present invention.
It will be appreciated by persons skilled in the art that the effects that can be achieved by the present invention are not limited to what has been particularly described hereinabove and other advantages of the present invention will be more clearly understood from the following detailed description.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.
FIG. 1 is a flow chart of a method for override of NOx spike in a NOx removal ammonia injection system according to an embodiment of the present invention;
fig. 2 is a logic diagram of an override method for solving the sudden increase of NOx concentration in the denitration ammonia injection system according to the embodiment of the present invention.
Detailed Description
Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention, rather than to show the only embodiments that can be implemented according to the present invention. The following detailed description includes specific details in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.
In some instances, well-known structures and devices are omitted or shown in block diagram form, focusing on important features of the structures and devices so as not to obscure the concept of the present invention. The same reference numbers will be used throughout the specification to refer to the same or like parts.
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "center", "inner", "outer", "top", "bottom", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Fig. 1 shows a flowchart of an override method for solving the sudden increase of NOx concentration in a denitration ammonia injection system according to an embodiment of the present invention. As shown in figure 1, aiming at the special working condition that the load rises and the concentration of NOx at an outlet rises simultaneously, a data judgment mode is used, when the existing NOx and unit load parameters exceed the original data within a certain time and reach a certain amplitude value, an override feedforward is triggered, so that an ammonia injection valve is opened rapidly, and the ammonia injection flow reaches the requirement of the load change working condition so as not to exceed the smoke emission limit value.
The two-stage override is to further raise the load-rise inlet NOx concentration variation standard on the basis, trigger the two-stage override when the load-rise speed and the outlet NOx concentration rise variation rate reach the second stage standard, and trigger the one-stage override to continue to inhibit the outlet NOx concentration from further rising suddenly.
Fig. 2 is a logic diagram illustrating an override method for solving the NOx concentration surge in the NOx removal ammonia injection system according to an embodiment of the present invention. In the method as described above, there is an inertia link after the primary and secondary override feedforward. Optionally, in the method as described above, the inertial element is timed
The invention adds double-override control logic on the basis of the existing best automatic control ammonia injection system, and can effectively ensure that the sudden increase of the concentration of the nitrogen oxide at the outlet can be timely controlled by the ammonia injection flow feedforward when special working conditions occur, thereby improving the stability of the automatic ammonia injection control system.
From the above description of the embodiments, it is obvious for those skilled in the art that the present application can be implemented by software and necessary general hardware, and of course, can also be implemented by hardware. Based on such understanding, the technical solutions of the present application may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as a floppy disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a FLASH Memory (FLASH), a hard disk or an optical disk of a computer, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the methods described in the embodiments of the present application.
As mentioned above, a detailed description of the preferred embodiments of the invention has been given to enable those skilled in the art to make and practice the invention. Although the present invention has been described with reference to exemplary embodiments, those skilled in the art will appreciate that various modifications and changes can be made in the present invention without departing from the spirit or scope of the invention described in the appended claims. Thus, the present invention is not intended to be limited to the particular embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (3)
1. An override method for addressing NOx spike in a NOx removal ammonia injection system, the method comprising:
under the special condition that the unit load rises and the concentration of the outlet NOx rises simultaneously, when the parameters of the existing outlet NOx and the unit load exceed original data and reach a certain amplitude value within a certain time, a primary override feedforward is triggered, so that an ammonia injection valve is rapidly opened, the ammonia injection flow rate meets the requirement of a load change working condition, and the smoke emission limit value is not exceeded; and
the unit load rise and outlet NOx concentration change criteria are further increased, a second level override feedforward is triggered when the rate of rise of the unit load and the rate of change of rise of the outlet NOx concentration reach a second level criteria, and a first level override feedforward continuation is triggered to inhibit further increases in the outlet NOx concentration.
2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,
wherein an inertial link follows the primary override feedforward and the secondary override feedforward.
3. The method of claim 2, wherein the first and second light sources are selected from the group consisting of,
characterized in that the inertia link is timed as
s is the laplace operator.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010335418.3A CN111495129B (en) | 2020-04-24 | 2020-04-24 | Override control method for solving sudden rising of NOx concentration in denitration ammonia injection system |
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| CN202010335418.3A CN111495129B (en) | 2020-04-24 | 2020-04-24 | Override control method for solving sudden rising of NOx concentration in denitration ammonia injection system |
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| CN111495129B true CN111495129B (en) | 2021-04-13 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4504286A (en) * | 1984-04-25 | 1985-03-12 | Phillips Petroleum Company | Automatic drying tower switching system |
| CN103728994A (en) * | 2013-12-30 | 2014-04-16 | 北京工业大学 | Cement plant SCR denitration efficiency monitoring control method |
| CN106512723A (en) * | 2016-12-26 | 2017-03-22 | 大唐黑龙江发电有限公司哈尔滨第热电厂 | Denitration automatic regulating loop device |
| CN106799123A (en) * | 2017-02-22 | 2017-06-06 | 上海龙净环保科技工程有限公司 | The control method and its control device of a kind of denitrification apparatus ammonia spraying amount |
| CN106873381A (en) * | 2017-04-10 | 2017-06-20 | 内蒙古瑞特优化科技股份有限公司 | Spray ammonia control system |
| CN108144446A (en) * | 2016-12-09 | 2018-06-12 | 上海明华电力技术工程有限公司 | One kind is based on SCR inlet NOXThe denitration control method of prediction |
-
2020
- 2020-04-24 CN CN202010335418.3A patent/CN111495129B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4504286A (en) * | 1984-04-25 | 1985-03-12 | Phillips Petroleum Company | Automatic drying tower switching system |
| CN103728994A (en) * | 2013-12-30 | 2014-04-16 | 北京工业大学 | Cement plant SCR denitration efficiency monitoring control method |
| CN108144446A (en) * | 2016-12-09 | 2018-06-12 | 上海明华电力技术工程有限公司 | One kind is based on SCR inlet NOXThe denitration control method of prediction |
| CN106512723A (en) * | 2016-12-26 | 2017-03-22 | 大唐黑龙江发电有限公司哈尔滨第热电厂 | Denitration automatic regulating loop device |
| CN106799123A (en) * | 2017-02-22 | 2017-06-06 | 上海龙净环保科技工程有限公司 | The control method and its control device of a kind of denitrification apparatus ammonia spraying amount |
| CN106873381A (en) * | 2017-04-10 | 2017-06-20 | 内蒙古瑞特优化科技股份有限公司 | Spray ammonia control system |
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