JP3801263B2 - Emulsion fuel control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for controlling a mixing ratio of emulsion fuel applied to a diesel engine.
[0002]
[Prior art]
Since marine diesel engines are used in the vast ocean, air pollutants in exhaust gas were not considered as a problem. However, maritime traffic has become more complex with the increase in marine transport volume, and marine diesel engines have been recognized as a source of air pollution in areas close to the coast and heavy traffic.・ NOx and SOx emission regulations are being discussed and put into practice at the Marine Environment Protection Committee (MEPC).
[0003]
Examples of NOx reduction techniques that can be implemented or are in service include water spraying into the air supply, water spraying into the cylinder, multi-port fuel spraying, and the use of emulsion fuel. It is explanatory drawing of a fundamental structure of an example of the conventional control apparatus of an emulsion fuel which adjusts the flow volume of water among both water and water, and controls the mixing ratio of an emulsion fuel.
[0004]
In FIG. 6, reference numeral 1 denotes an emulsion fuel generation device, which is a heavy oil flow meter 6, an emulsion fuel flow meter 7, an automatic control device 8, a water supply pump 9, a mixing device 10, and a pipe line indicated by a solid line communicating between them. The heavy oil flow meter 6 is in communication with the heavy oil tank 2 and the water supply pump 9 is in communication with the water tank 3. A diesel engine 4 is supplied with emulsion fuel from the generator 1.
[0005]
The operation of the above configuration will be described below with reference to the flowchart shown in FIG.
In the conventional apparatus, when the emulsion fuel is generated, the engine operator first sets the mixing ratio of the heavy oil F and the water W in advance according to the operating state of the engine.
Flow signals of heavy oil F and emulsion fuel (F + W) measured from the heavy oil flow meter 6 and the emulsion fuel flow meter 7 are output and input to the automatic controller 8.
[0006]
The automatic control device 8 calculates an actual mixing ratio of the heavy oil F and the water W based on the input flow rate signals of the heavy oil F and the emulsion fuel (F + W) and compares it with a preset mixing ratio.
As a result of the comparison, if the mixing ratio of water W is smaller than the set value, an instruction signal for increasing the supply current to the water supply pump 9 is output to increase the mixing ratio of water W. The rotation speed of the water supply pump 9 increases, and the mixing ratio of the water W increases.
[0007]
On the contrary, when the mixing ratio of the water W is larger than the set value, an instruction signal for decreasing the supply current to the water supply pump 9 is output to reduce the mixing ratio of the water W. If the mixing ratio of the water W is at the same level as the set value, the current state is maintained.
[0008]
As a conventional example using emulsion fuel, there is an example in which a service vessel using an emulsion fuel mixed with about 10% of water has been operated for a long time. When the mixing ratio of water is about 30% of the fuel, the flame temperature is lowered by the evaporation and thermal dissociation of water, and NOx is reduced by about 30%. At the same time, as the water enters, the momentum of the injected fuel is increased and the dispersion of the spray is improved.
[0009]
[Problems to be solved by the invention]
However, the conventional emulsion fuel control device has the following problems.
That is, in the conventional apparatus, the mixing ratio of heavy oil and water has to be set in advance by the engine operator in accordance with the operating state of the engine.
[0010]
Therefore, the mixing ratio varies depending on the level of skill of the individual operator, resulting in problems such as deterioration in fuel consumption due to supply of more water than necessary, and increase in NOx concentration in exhaust gas due to insufficient water supply. There is a fear. Further, since the NOx concentration varies depending on the operating conditions, it is extremely difficult to set the emulsion fuel mixing ratio so that the target value such as the environmental regulation value is always satisfied.
[0011]
The object of the present invention is to solve the above problems, measure the NOx concentration in the exhaust gas, and automatically and accurately adjust the mixing ratio of the emulsion fuel based on the measured value. An object of the present invention is to provide an emulsion fuel control device that can reduce the NOx emission concentration to a desired level without any problems.
[0012]
[Means for Solving the Problems]
Controller of the emulsion fuel of the present invention, in the control apparatus of the emulsion fuel of a diesel engine equipped with a control means for controlling any mixing ratio with one of the flow rate adjusted to an emulsion fuel of heavy oil and water, in the exhaust gas NOx concentration measuring means for detecting the NOx concentration of the water, and setting means for setting the relationship between the NOx concentration and the upper limit value of the water mixing ratio in the emulsion fuel, and the water mixing ratio in the emulsion fuel Is compared with the upper limit set value of the mixing ratio set in the setting means, the measured value of NOx concentration from the NOx concentration measuring means is compared with a preset target NOx concentration, When the measured value of the mixing ratio of water is not more than the upper limit set value of the mixing ratio and the measured value of the NOx concentration is higher than the target NOx concentration, the water supply pump A control device that increases the amount, and decreases the flow rate of the water supply pump when the measured value of the mixing ratio of water is equal to or lower than the upper limit set value of the mixing ratio and the measured value of NOx concentration is lower than the target NOx concentration. is characterized in that provided was.
[0013]
Specifically, a heavy oil flow meter, an emulsion fuel flow meter, an automatic control device, a water supply pump, a mixing device, an emulsion fuel generation device comprising a pipe line and a control circuit communicating between them, a heavy oil tank and a water tank And an exhaust gas measuring device that detects the concentration of NOx in the exhaust gas and outputs measured data to the automatic control device in the emulsion fuel generating device.
[0014]
[Action]
Next, the operation of the means of the present invention having the above configuration will be described.
The NOx concentration in the target exhaust gas and the upper limit value of the mixing ratio of water W in the emulsion fuel (F + W) are set in advance.
In the emulsion fuel generation device, the flow signal output from the heavy oil flow meter and the emulsion fuel flow meter and the signal of the actual measurement data of NOx concentration in the exhaust gas output from the exhaust gas measurement device are input to the automatic control device. The
[0015]
In the automatic control device, the mixing ratio of the heavy oil F and the water W of the emulsion fuel (F + W) is calculated and compared with the preset upper limit value of the mixing ratio of the water W. As a result of this comparison, when it is determined that the mixing ratio of water W based on the actual measurement data is larger than the set upper limit value, an instruction signal for decreasing the supply current to the water supply pump is output to reduce the mixing ratio of water W Is done.
[0016]
Further, when it is determined that the mixing ratio of water W based on the actual measurement data is smaller than or equal to the upper limit value of the mixing ratio of water W, the NOx concentration in the exhaust gas based on the actual measurement data is set in advance. Compare the target NOx concentrations.
When the measured NOx concentration is higher than the target NOx concentration as a result of the comparison of the NOx concentration, an instruction signal for increasing the supply current to the water supply pump is output to increase the mixing ratio of the water W in order to lower the measured NOx concentration. Is done.
[0017]
On the contrary, when the measured NOx concentration is lower than the target NOx concentration, an instruction signal for decreasing the supply current to the water supply pump is output in order to reduce the mixing ratio of the water W. If the measured NOx concentration is equal to the target NOx concentration, the current state is maintained.
[0018]
Due to the above-described operation, the mixing ratio of the heavy oil F and water W of the emulsion fuel (F + W) is automatically and accurately adjusted according to the operating state of the engine, without depending on the judgment based on the experience of the engine operator. The emulsion fuel is supplied to the engine after sufficient emulsification. This functions as an emulsion fuel control device that can reduce the NOx concentration in the exhaust gas to a desired level.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory diagram of the configuration of an emulsion fuel control device according to an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of this configuration. The configuration and operation will be described below with reference to FIGS.
[0020]
In FIG. 1, reference numeral 1 denotes an emulsion fuel generation device, which is a heavy oil flow meter 6, an emulsion fuel flow meter 7, an automatic control device 8, a water supply pump 9, a mixing device 10, and a pipe line indicated by a solid line communicating between them. The heavy oil flow meter 6 is in communication with the heavy oil tank 2 and the water supply pump 9 is in communication with the water tank 3. A diesel engine 4 is supplied with emulsion fuel from the generator 1. An exhaust gas measuring device 5 extracts and analyzes exhaust gas from the exhaust pipe of the diesel engine 4, and outputs a signal about the concentration of NOx to the automatic control device 8.
[0021]
Next, the operation of the above configuration will be described with reference to the flowchart of FIG. The NOx concentration in the target exhaust gas and the upper limit value of the mixing ratio of water W in the emulsion fuel (F + W) are set in advance. An example of this setting is shown in FIG.
In the emulsion fuel generation device 1, the flow signal of heavy oil F output from the heavy oil flow meter 6, the flow signal of emulsion fuel (F + W) output from the emulsion fuel flow meter 7, and the exhaust gas measurement device 5 output it. A signal of measured data of NOx concentration in the exhaust gas is input to the automatic control device 8.
[0022]
In the automatic control device 8, the mixing ratio of the heavy oil F and the water W of the emulsion fuel (F + W) is calculated and compared with the preset upper limit value of the mixing ratio of the water W.
As a result of this comparison, when it is determined that the mixing ratio of the water W based on the actual measurement data is larger than the preset upper limit value of the mixing ratio of the water W, the water supply pump 9 is used to reduce the mixing ratio of the water W. An instruction signal for reducing the supply current to the water is output, the rotation speed of the water supply pump 9 is reduced, and the mixing ratio of the water W is reduced.
[0023]
Further, when it is determined that the mixing ratio of water W based on the actual measurement data is smaller than or equal to the upper limit value of the mixing ratio of water W, the NOx concentration in the exhaust gas based on the actual measurement data is set in advance. Compare the target NOx concentrations.
[0024]
If the measured NOx concentration is higher than the target NOx concentration as a result of the comparison of the NOx concentration, an instruction signal for increasing the supply current to the water supply pump 9 is output to increase the mixing ratio of the water W, and the water supply pump 9 The number of rotations increases, and the mixing ratio of water W increases. On the other hand, when the measured NOx concentration is lower than the target NOx concentration, an instruction signal for decreasing the supply current to the water supply pump 9 is input in order to reduce the mixing ratio of the water W. If the measured NOx concentration is equal to the target NOx concentration, the current state is maintained.
[0025]
As described above, in the emulsion fuel generation device 1, the flow rate signals output from the heavy oil flow meter 6 and the emulsion fuel flow meter 7 and the NOx concentration measurement data signal output from the exhaust gas measurement device 5 are automatically controlled. 8, and the water supply pump 9 is controlled based on the processing results of the calculation, comparison, and determination in the automatic control device 8, so that the mixing ratio of the heavy oil F and water W of the emulsion fuel (F + W) is set. Automatically and accurately so as to meet the above.
[0026]
Thereafter, the emulsion fuel is supplied to the diesel engine 4 after sufficiently emulsifying with the mixing device 10.
Thus, it functions as an emulsion fuel control device capable of reducing the NOx concentration in the exhaust gas to a desired level without making a judgment based on the experience of the engine operator.
[0027]
FIG. 4 shows an example of the relationship between the engine speed and the NOx concentration in the exhaust gas when the diesel engine 4 is operating with the sufficiently emulsified fuel supplied through the mixing device 10. Curve C in the figure is a NOx concentration guideline set in advance as a target. In the region R, the actually measured concentration exceeds the target concentration, and in the region L, the actually measured concentration is below the target concentration.
[0028]
During the operation of the engine, the NOx concentration in the exhaust gas is measured by the exhaust gas measuring device 5, and the data is input to the automatic control device 8 together with the flow signals of heavy oil F and emulsion fuel (F + W), and the measured NOx concentration is in the region R. When it is, the water supply pump 9 is controlled so as to move to the region L, and the mixing ratio of the heavy oil F and the water W is changed to reduce the exhaust NOx.
[0029]
FIG. 5 shows an example of the relationship between the rated rotational speed of a marine diesel engine using emulsion fuel and the weighted average value of NOx emissions per unit output (g / kw · h). Curve C in the figure is a guideline based on the proposed environmental regulations of the International Maritime Organization (IMO). The water supply pump 9 is controlled by calculation, comparison and determination in the automatic control device 8 based on the measured NOx concentration in the exhaust gas so that the weighted average value of the discharge amount per unit output of NOx falls within the region A. The mixing ratio of F and water W is changed, and control is performed so as to always operate within the regulation value.
[0030]
【The invention's effect】
According to the emulsion fuel control device of the present invention, based on the measured data of NOx concentration in the exhaust gas, the mixing ratio of heavy oil and water in the emulsion fuel is automatically and accurately adjusted so as to match a preset target value. Is done.
As a result, the NOx concentration in the exhaust gas can be reduced to a desirable level that satisfies the regulation value, without making a determination based on the experience of the engine operator.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of the configuration of an emulsion fuel control device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the emulsion fuel control device shown in FIG. 1;
FIG. 3 is an explanatory diagram of a relationship between a target value of NOx concentration referred to in the first step of the flowchart shown in FIG. 2 and a mixing ratio of heavy oil and water of emulsion fuel.
FIG. 4 is an explanatory diagram of the relationship between engine speed and exhaust NOx concentration.
FIG. 5 is an explanatory diagram of the relationship between the rated engine speed and the weighted average value of emissions per unit output of NOx.
FIG. 6 is a diagram illustrating the configuration of a conventional emulsion fuel control device.
7 is a flowchart for explaining the operation of the conventional emulsion fuel control device shown in FIG. 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Emulsion fuel generator 2 Heavy oil tank 3 Water tank 4 Diesel engine 5 Exhaust gas measuring device 6 Heavy oil flow meter 7 Emulsion fuel flow meter 8 Automatic control device 9 Water supply pump 10 Mixing device

Claims (1)

NOx concentration measuring means for detecting NOx concentration in exhaust gas in control apparatus for emulsion fuel of diesel engine, comprising control means for controlling mixing ratio of emulsion fuel by adjusting flow rate of either heavy oil or water And a setting means for setting the relationship between the NOx concentration and the upper limit value of the mixing ratio of water in the emulsion fuel, and the setting value is set in the measured value of the mixing ratio of water in the emulsion fuel and the setting means. The upper limit set value of the mixing ratio is compared, the measured value of NOx concentration from the NOx concentration measuring means is compared with a preset target NOx concentration, and the measured value of the mixing ratio of water is the mixed value. When the measured value of the NOx concentration is lower than the upper limit set value of the ratio and is higher than the target NOx concentration, the flow rate of the water supply pump is increased to calculate the water mixing ratio. Controller of the emulsion fuel when the measured value of and NOx concentration than the upper limit value and the value set is the mixing ratio is lower than the target NOx density, characterized in that it includes a control device allowed to reduce the flow rate of the water supply pump .

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