JPH0212609B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a flue gas desulfurization device for separating and removing sulfur oxides contained in exhaust gas generated in a metal refining process or the like. [Prior Art] Conventionally, as shown in FIG. 4, this type of flue gas desulfurization equipment includes an absorption tower 2 to which one end of a duct (passage) 1 is connected, and a pipe 3 connected to the absorption tower 2. An oxidation tower 4 is connected to the oxidation tower 4 via a pipe 5.
A flue gas desulfurization apparatus is known which is configured to include a compressor 6 connected to the compressor 6 via a compressor 6. In this flue gas desulfurization equipment, the absorption tower 2 cleans the exhaust gas fed into the interior from the duct 1 with a suspension of slaked lime (a basic substance), and cleans the exhaust gas (sulfur dioxide gas) contained in the exhaust gas. Calcium sulfite) is separated and removed as calcium sulfite (sulfite). In addition, the oxidation tower 4 oxidizes the calcium sulfite fed into the interior from the pipe 3 with oxygen,
This is made harmless by converting it into calcium sulfate (sulfate). The compressor 6 is for supplying gaseous oxygen into the oxidation tower 4, and is designed to be able to send a certain amount of air through the pipe 5. [Problems to be Solved by the Invention] By the way, the concentration of sulfur dioxide gas contained in exhaust gas constantly changes, and the amount of calcium sulfite produced in the absorption tower changes accordingly. However, since the above flue gas desulfurization equipment is configured to always supply a fixed amount of gaseous oxygen into the oxidation tower, the amount of gaseous oxygen to be supplied corresponds to the maximum amount of calcium sulfite produced. Therefore, there was a problem in that the power consumption of the compressor became larger than necessary. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flue gas desulfurization device that requires less power consumption in a compressor. [Means for Solving the Problems] The flue gas desulfurization apparatus of the present invention includes a measuring means for measuring the amount of sulfur oxide flowing in the passage in the passage for feeding exhaust gas to the absorption tower. Compare the amount of sulfur oxide measured by this measuring means with the air supply amount of the compressor measured by a flow rate measuring device installed in the passage for feeding gaseous oxygen to the oxidation tower. and controlling the frequency and voltage of the drive current to be supplied to the compressor, thereby controlling the rotation speed of the compressor,
Accordingly, a control device is provided to increase or decrease the amount of air supplied by the compressor in accordance with the amount of sulfur oxide. [Embodiment] FIG. 1 is a diagram showing an embodiment of a flue gas desulfurization apparatus according to the present invention. The flue gas desulfurization apparatus according to this embodiment has an absorption tower, an oxidation tower, a compressor, and a control device for increasing/decreasing the amount of air supplied by the compressor as the main components, and is constructed as follows. In FIG. 1, numeral 7 indicates multiple units (in the figure, 2
This is an absorption tower installed. The absorption tower 7 cleans the exhaust gas fed into the interior with a suspension of slaked lime (a basic substance), and converts sulfur dioxide gas (sulfur oxides) contained in the exhaust gas into calcium sulfite (sulfite). The end of a duct (passage) 8 is connected to its side wall. The duct 8 is for sending exhaust gas into the absorption tower 7, and a measuring device (measuring means) 9 is installed in the middle of the duct to measure the amount of sulfur dioxide gas contained in the exhaust gas. . Further, a plurality of oxidation towers (two in the figure) 10, 10 are connected to the absorption towers 7, 7, respectively, by pipes 12, 12 having pumps 11, 11 interposed therebetween. The pumps 11, 11 take in the calcium sulfite produced in the absorption towers 7, 7 into pipes 12, 12, and transport it to the oxidation towers 10, 12.
It is to be sent within 10 days. In addition, oxidation tower 1
No. 0,10 oxidizes the above calcium sulfite with oxygen and renders it harmless as calcium sulfate (sulfate). And each oxidation tower 1
0 and 10 are provided with a waste discharge device (not shown), so that calcium sulfate is discharged to the outside. Further, a plurality of compressors 13, 13, . . . are connected to these oxidation towers 10, 10 via piping 14. This piping 14 is equipped with a flow rate measuring device 15 and a flow rate regulating valve 16 on each oxidation tower 10, 10 side, and all compressors 1 on the compressor 13, 13... side.
A flow rate measuring device 17 for measuring the amount of air supplied by 3, 13, . . . is interposed. Compressor 13,
Reference numeral 13 supplies gaseous oxygen into the oxidation towers 10, 10, and the supply amount can be increased or decreased by a control device to be described later. Next, a control device for controlling the amount of air supplied by the compressors 13, 13 will be explained.
The control device includes an addition section 18 and calculation sections 19 and 20.
and an output section 21. Addition section 1
Reference numeral 8 adds the measurement results of the measuring instruments 9 and 9, and outputs the addition result to the calculation section 19. In addition, the calculation unit 19
The amount of sulfur dioxide gas based on the addition result of the addition unit 18,
The frequency and voltage of the driving current to be supplied to the compressors 13, 13 are calculated by comparing the amount of air supplied to the compressors 13, 13... measured by the flow rate measuring device 17, and the results of this calculation are sent to the output section. 21. The output section 21 is configured to control and convert the frequency and voltage of the supplied AC power supply based on the input signal from the calculation section 19, and supply this to the compressors 13, 13. Further, the calculation unit 20 calculates the amount of air to be supplied to the oxidation tower 10 from the amount of sulfur dioxide gas measured by the measuring device 9, and based on the calculation result, each flow rate control valve 16,
16, so that an appropriate amount of air is distributed and supplied to each oxidation tower 10, 10. In the flue gas desulfurization apparatus having the above configuration, flue gas desulfurization treatment is performed as follows. That is,
First, the exhaust gas flows from the ducts 8, 8 to the absorption towers 7, 7.
and washed with a suspension of slaked lime. Then, the sulfur dioxide gas contained in the exhaust gas reacts with the slaked lime and is separated and removed as calcium sulfite. Next, this calcium sulfite pump 11,
11 into the oxidation towers 10, 10.
On the other hand, an appropriate amount of gaseous oxygen is fed into the oxidation towers 10, 10 under the control of a control device. Then, calcium sulfite is oxidized by oxygen,
Detoxified as calcium sulfate. Note that calcium sulfate is discharged to the outside by a discharge device. In the above embodiment, the compressor 13, 1 is
Since a control device for increasing and decreasing the amount of air supplied by compressor 3 is provided, wasteful power consumption by compressors 13 and 13 can be prevented. In addition, in order to increase or decrease the amount of air supplied by the compressor, an air tank (accumulator) is provided at the outlet of the compressor, and the compressor is repeatedly loaded and unloaded according to the pressure setting value of this air tank. It is possible to increase or decrease the supply amount of air or install multiple compressors to increase or decrease the supply amount of air depending on the number of compressors in operation, but in the former case, the air tank (accumulator),
A device to control the ON/OFF of the compressor is required, making the flue gas desulfurization equipment more complicated and prone to breakdowns, and also turning the compressor ON/OFF.
However, in the latter case, a considerable number of compressors are required to accurately control the amount of air supplied;
The disadvantage is that there is a large loss of air and electricity due to turning it on and off. On the other hand, in the flue gas desulfurization apparatus of the above embodiment, the compressor 13,
13, the supply of air can be controlled without using a device that controls the accumulator or compressor on and off, or without turning the compressor on and off. Can be controlled easily and accurately. Therefore, the power consumption in the compressor can be significantly reduced compared to the conventional compressor, and failures are less likely to occur. Incidentally, the power consumption relative to the rotation speed (airflow amount) of the compressors 13, 13, as shown by the solid line in FIG. 2, is lower than that of the conventional system (shown by the broken line).
In particular, it can be seen that when the number of revolutions (amount of air blown) of the compressors 13, 13 is small, the amount is extremely small. In addition, in the above embodiment, three compressors 13
..., but in this invention, a compressor is used.
Since there is no need to turn it on and off, the amount of air supplied can be controlled with a single compressor depending on the processing capacity of the flue gas desulfurization equipment. In addition, in the above embodiment, the amount of sulfur dioxide gas contained in the exhaust gas during flue gas desulfurization treatment is
As shown in Figure 3, it changed over time. and,
As shown in Table 1, two compressors 13,
The average power consumption by 13 is 160KWH,
This is a reduction of 240KWH compared to the previous model.

[Table] [Effects of the Invention] As explained above, in the flue gas desulfurization device of the present invention, the amount of sulfur oxides flowing in the passage is measured during the passage for sending exhaust gas to the absorption tower. A measuring means is provided, and the amount of sulfur oxide is measured by the measuring means, and the air supply of the compressor is measured by a flow meter provided in a passage for feeding gaseous oxygen to the oxidation tower. The number of rotations of the compressor is controlled by controlling the frequency and voltage of the drive current to be supplied to the compressor, thereby controlling the supply of air by the compressor according to the amount of sulfur oxides. Since a control device for increasing and decreasing the amount is provided, it is possible to obtain the effect that power consumption in the compressor can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a diagram showing a schematic diagram of an exhaust gas desulfurization device, and FIG. 2 is a diagram showing the relationship between compressor rotation speed (airflow amount) and power consumption. FIG. 3 is a diagram showing temporal changes in the amount of sulfur dioxide contained in exhaust gas, and FIG. 4 is a schematic diagram showing a conventional flue gas desulfurization device. 1...Duct (passage), 2...Absorption tower, 4...
Oxidation tower, 6... Compressor (air supply machine),
7... Absorption tower, 8... Duct (passage), 9... Measuring device (measuring means), 10... Oxidation tower, 13... Compressor (air supply machine).

Claims (1)

[Claims] 1 An absorption tower that generates sulfite by reacting a basic substance with sulfur oxides contained in the exhaust gas fed into the interior, and an oxidation tower that generates sulfate by reacting the sulfite with oxygen. In a flue gas desulfurization device comprising a compressor for supplying gaseous oxygen to the oxidation tower, the amount of sulfur oxides flowing in the passage for supplying exhaust gas to the absorption tower is measured. The amount of sulfur oxide measured by the measuring means and the air in the compressor measured by a flow rate measuring device provided in the passage for feeding gaseous oxygen to the oxidation tower. The rotational speed of the compressor is controlled by controlling the frequency and voltage of the drive current to be supplied to the compressor by comparing it with the supply amount, thereby controlling the air flow by the compressor according to the amount of sulfur oxide. A flue gas desulfurization device characterized by being equipped with a control device that increases or decreases the supply amount.