JPH0726943A - Control method for denitration device - Google Patents

Abstract

PURPOSE:To control the filling amount of ammonia in high accuracy same as the case of a NOx analyzer arrangement at a low cost, and to control response to an engine load earlier than the case of using an NOx analyzer. CONSTITUTION:In control method of a denitration device arranged in such a manner that a denitration device 22 is connected to an engine 21 provided with an output detector 24 or a gas turbine and exhaust gas discharged from the engine 21 or the gas turnine is discharged toward the atmosphere, a central processing unit 25 is connected to the output detector 24. A signal converter 26 and a control valve 27 for controlling the filling amount of ammonia which is necessary for denitration are connected to the central processing unit 25, and two and more elements in 8 elements of an atmosphere temperature, atmosphere pressure, atmosphere humidity, the scavenging temperature after an air cooler, the amount injected water or steam toward a combustion chamber, a ratio including nitrogen in fuel, a piston compressing rate, and a fuel injection timing delay amount are inputted into the central processing unit 25. It is thus possible to correct a signal which is a base for controlling the filling amount of ammonia.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a denitration device, and more particularly to an anomonia injection control method for a denitration device for a diesel engine, a gas engine or a gas turbine.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional denitration system flow. Further, FIG. 4 shows a flow of a conventional ammonia injection control signal. Reference numeral 1 in the drawing is a diesel engine (or gas engine or gas turbine). A chimney 3 is connected to the diesel engine 1 via a denitration device 2. As a result, the exhaust gas discharged from the diesel engine 1 is guided to the chimney 3 through the denitration device 2 and is discharged to the atmosphere. The diesel engine 1 is provided with an engine output detector 4. The engine output detector 4 includes a function generator 5, a multiplier 6, and
The signal converter 7 and the ammonia injection amount control valve 8 are sequentially connected. An engine outlet NOx concentration analyzer 9 is connected to the multiplier 6. In the figure, reference numeral 10 is an ammonia injection nozzle, reference numeral 11 is ammonia, and reference numeral 12 is NO.
x correction signal. The injection amount of ammonia required for denitration is determined by the signal from the engine output detector 4 and the NOx concentration analyzer 9
Is calculated from the output signal of the above, and is controlled by the ammonia injection amount control valve 8 so that the injection amount becomes appropriate each time.

[0003]

By the way, in the denitrification device in which highly precise denitration (following the NOx concentration at the engine outlet as much as possible and always making the injected ammonia amount appropriate) is strongly demanded, the NOx concentration at the engine outlet itself. Is detected and introduced into the ammonia injection amount control device to directly control the ammonia injection amount.
In this case, the use of a NOx concentration analyzer has the following problems. (1) The NOx concentration analyzer is extremely expensive at 2 to 5 million yen / unit. (2) The NOx concentration analyzer is very complicated to handle because it repairs the internal equipment, periodically calibrates the indicated value, and replenishes the standard gas. (3) In order to follow the output signal of the NOx concentration analyzer, a response delay of several tens of seconds is essential in the analysis due to the introduction time of the sample gas introduction line and the response time of the NOx concentration analysis unit.
In particular, there is a problem in response when the engine load change is complicated.

The present invention has been made in consideration of such circumstances, and it is possible to perform the ammonia injection amount control with high accuracy equivalent to the case where the NOx analyzer is installed at a low price, and to compare with the case where the NOx analyzer is used. An object of the present invention is to provide a method for controlling a denitration device that enables quick control of engine load response.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for controlling a denitration device, in which a denitration device is connected to an engine or a gas turbine equipped with an output detector, and exhaust gas discharged from the engine or the gas turbine is released to the atmosphere. , A central processing unit is connected to the output detector, a signal converter and a control valve for controlling the injection amount of ammonia required for denitration are connected to the central processing unit, and the atmospheric temperature, atmospheric pressure, atmospheric humidity, air Two or more of the eight elements of the scavenging temperature after the cooler, the amount of water or steam injected into the combustion chamber, the nitrogen content in the fuel, the piston compression ratio, and the fuel injection timing delay amount are input to the central processing unit, A method for controlling a denitration device is characterized in that a signal serving as a reference for controlling an ammonia injection amount is corrected.

In the present invention, the signal serving as a reference for controlling the amount of injected ammonia is, for example, data obtained by previously measuring the engine outlet exhaust gas amount and the engine outlet NOx concentration which serve as the reference for control at each engine output from the engine output signal. Is a signal indicating the total amount of NOx at the engine outlet, which is obtained by an arithmetic expression previously incorporated based on the above equation and is calculated by multiplying the two signals.

[0007]

In the present invention, N discharged from the engine
Ox concentration is atmospheric temperature, atmospheric pressure, atmospheric humidity, scavenging humidity after air cooler in reciprocating internal combustion engine with intermediate air cooler, nitrogen content in fuel and engine tuning factors (piston compression ratio, fuel The correlation between each element and the NOx concentration exhausted from the engine varies empirically as the type of each engine and the characteristics of the model.

Therefore, if the characteristics of all or some of these elements are incorporated in the central processing unit in advance and the signals represented by each element are input from the respective detectors or directly to the arithmetic units, they are discharged from the engine. The ammonia injection amount control can be appropriately performed with high accuracy and without time delay by using a signal that accurately and proactively calculates the NOx concentration according to the present invention.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Reference numeral 21 in the drawing is a diesel engine (or gas engine or gas turbine). This diesel engine 21 has a chimney 23 through a denitration device 22.
Are connected. The diesel engine 21 is provided with an engine output detector 24. A central processing unit (CPU) 25, a signal converter 26, and an ammonia injection amount control valve 27 are sequentially connected to the engine output detector 24. Note that the reference numeral 28 in the figure is the ammonia injection nozzle, the reference numeral
29 is ammonia.

In FIG. 1, the NOx concentration correction signal 30 is applied to the CPU 25. The temperature, pressure, etc. of the atmosphere (air) are adjusted to the diesel engine 21, and the diesel engine 21 is injected together with the fuel to discharge the combustion exhaust gas. Ammonia 29 adjusted by the ammonia injection amount control valve 27 is injected into the exhaust gas by the ammonia injection nozzle 28 and mixed, and then N 2 is discharged in the denitration device 22.
After removing Ox, it is guided to the chimney 23 and emitted to the atmosphere. The signal obtained from the engine output detector 24 is the CPU 25.
To the signal converter 26, and the ammonia injection amount control valve 27 is adjusted via the signal converter 26.

The NOx correction signals 30 and 31 are fluctuation value corrections.
Atmospheric pressure, atmospheric humidity, scavenging temperature and water or water vapor injection amount are obtained, and this signal is input to the function generating function c. Also,
The NOx correction signal 31 is a fixed value correction, and the nitrogen content in the fuel, engine tuning factors (piston compression ratio, fuel injection timing delay amount, etc.) are obtained by each sensor (not shown), and this signal is used as a function generating function d. It is configured to input to.

FIG. 2 shows the NOx concentration in the CPU and the mechanism of correction. A fluctuation value correction signal as the NOx correction signal 30 is taken into the CPU 25 as a signal transmitted by each sensor provided separately, and the control reference signal is corrected by the corrected signal 32 generated by a function corresponding to each signal, Further, a fixed value correction signal is input by a separately provided input device, and the control reference signal 34 is further corrected by the corrected signal 33 generated by a function corresponding to each signal concerned, and then the signal converter. By controlling the ammonia injection amount control valve 27 via 26, highly accurate ammonia injection control can be performed without installing a NOx analyzer conventionally provided at the engine outlet (denitrification device inlet).

As described above, according to the above-described embodiment, the atmospheric temperature, atmospheric pressure, atmospheric humidity, scavenging temperature, and water or water vapor injection amount are obtained by each sensor (not shown), and this signal is input to the function generating function c. In addition, each sensor (not shown) obtains the nitrogen content in the fuel, engine tuning factors (piston compression ratio, fuel injection timing delay amount, etc.), and inputs this signal to the function generating function d. Without installing a NOx concentration analyzer at the engine outlet, it is possible to control the ammonia injection amount with high precision and always keep the NOx concentration at the outlet of the denitration device within the allowable range of the required value with high precision.

[0014]

As described above in detail, according to the present invention,
While it is possible to control the injection amount of ammonia with the same high precision as when installing a NOx analyzer at a low price,
It is possible to provide a highly reliable denitration control method capable of controlling the engine load response faster than when using a NOx analyzer.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a denitration device system flow according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a flow of an ammonia injection control signal according to the present invention.

FIG. 3 is an explanatory diagram of a conventional denitration system flow.

FIG. 4 is an explanatory diagram of a flow of a conventional ammonia injection control signal.

[Explanation of symbols]

21 ... Engine, 22 ... Denitration device,
23 ... Chimney, 24 ... Engine output detector, 25 ... Central processing unit, 26 ... Signal converter, 27 ... Ammonia injection amount control valve, 28 ... Ammonia injection nozzle, 29 ... Ammonia, 30, 31 ... NOx correction signal, 32 , 33 ... post-correction signal, 34 ... control reference signal.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B01D 53/74

Claims (2)

[Claims] 1. A method for controlling a denitration device, wherein a denitration device is connected to an engine or a gas turbine equipped with an output detector, and exhaust gas discharged from the engine or gas turbine is released to the atmosphere. In addition to connecting the device, a signal converter and a control valve for controlling the injection amount of ammonia required for denitration are connected to the central processing unit, and the atmospheric temperature, atmospheric pressure, atmospheric humidity, scavenging temperature after the air cooler, combustion Two or more of the eight elements of the amount of water or steam injected into the chamber, the nitrogen content in fuel, the piston compression ratio, and the fuel injection timing delay amount are input to the central processing unit to control the amount of ammonia injection. A method for controlling a denitration device, characterized by correcting the following signal. 2. The reference signal for controlling the ammonia injection amount is pre-installed based on the data obtained by previously measuring the engine outlet exhaust gas amount and the engine outlet NOx concentration, which are the reference for control at each engine output, from the engine output signal. 2. The denitration control method according to claim 1, wherein the signal is a signal indicating the total amount of NOx at the engine outlet, which is obtained by the above-mentioned arithmetic expression and is calculated by multiplying the two signals.