JPH0157247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a combustion apparatus for waste gas generated from the process of processing industrial waste such as plastics, particularly waste plastics.

(b) Prior Art and Problems In recent years, plants have been developed and put into practice that heat and melt industrial waste such as waste plastics, condense the generated gas, and recover it as oil.

Conventionally, waste gas generated from such industrial waste treatment processes has been disposed of by either being released into the atmosphere as is or simply being burned in the atmosphere. The former method pollutes the air and destroys the human and natural environments. In addition, although the latter treatment method can reduce the impact on the natural environment and human environment, it is not possible to fully As a result, toxic gases contained in the waste gas are released into the atmosphere without being combusted, which is dangerous and pollutes the atmosphere.Furthermore, the thermal energy from combustion of the waste gas is wasted. There was a problem that it was consumed.

(c) Purpose of the Invention The present invention solves the above-mentioned conventional problems, and its purpose is to utilize the waste gas generated in the waste treatment process as a heat source for the heating furnace in the waste treatment process, and to To provide a waste gas combustion device that enables combustion control according to the amount and composition of waste gas to completely burn the waste gas, eliminate danger, and prevent air pollution.

(d) Structure of the Invention In order to achieve the above object, the waste gas combustion apparatus of the present invention includes at least one burner mechanism that combines a plurality of burners with different combustion capacities, and a burner mechanism that corresponds to each burner of the burner mechanism. A mixer that is installed separately and mixes the waste gas and air, a blower that supplies air to each of the mixers, and a passage that connects each of the mixers and the blower to properly set the mixing ratio of the waste gas. a zero governor provided in a passage connecting the exhaust gas supply side and the mixer, an electromagnetic valve that opens and closes the passage, and a solenoid valve that opens and closes the passage, and detects the exhaust gas supply pressure. means for detecting the supply air pressure of the blower; and a means for controlling the opening and closing of the electromagnetic valve based on a signal corresponding to the gas pressure level from the waste gas pressure detection means and a signal from the air pressure detection means to detect the supply waste gas. The burner mechanism includes a control means for selecting a burner of the burner mechanism according to the pressure, and an ignition means for the burner mechanism.

(E) Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the waste gas combustion apparatus of the present invention, in which 1 is a scrubber for cleaning waste gas discharged from the process of treating waste such as waste plastics, and 2 is a scrubber 1 connected to the scrubber 1 via on-off valves 3 and 4. This strainer 2 is connected to the scrubber 1 to remove water and foreign substances from the waste gas.

A flow meter 5 is installed on the waste gas discharge side of the strainer 2.
The first mixer 6 and the second mixer 7 are connected in parallel via the flow meter 5 and the first mixer 6.
An on-off valve 8, a zero governor 9 for stabilizing combustion and preventing backfire, and an electromagnetic on-off valve 10 are connected in series to the passage connecting the flowmeter 5 and the second mixer 7. A similar on-off valve 11, zero governor 12, and electromagnetic on-off valve 13 are connected in series. The first and second mixers 6 and 7 mix waste gas and air at a predetermined ratio.

14 is a blower for supplying combustion air to the first and second mixers 6 and 7;
The first and second mixers 6 and 7 are connected to the discharge port of the flowmeter 1 through a flowmeter 15, and the flowmeter 1
5 and the first mixer 6 is connected in series with a flow rate regulating valve 16, and a passage connecting the flow meter 15 and the second mixer 7 is connected with an electromagnetic on-off valve 17 and a flow rate regulating valve. Valves 18 are connected in series. Further, 19 is an on-off valve connected in parallel to the electromagnetic on-off valve 17.

First small capacity burners 23a and 23b are connected to the mixed gas discharge side of the first mixer 6 via a switching valve 20 and flexible hoses 21a and 21b, and furthermore, the mixed gas discharge side of the second mixer 7 is connected to the mixed gas discharge side of the second mixer 7. There is a switching valve 25 and a flexible hose 22.
Large capacity burners 24a, 24b via a, 22b
is connected. The small-capacity burner 23a and the large-capacity burner 24a, and the small-capacity burner 23b and the large-capacity burner 24b are arranged close to each other in one group, and the burners in each group correspond to separate heating furnaces. Each small capacity burner 23a, 23b also serves as a pilot burner for the corresponding large capacity burner 24a, 24b.

26 and 27 are the small capacity burners 23a and 23b.
The ignition transformers 26 and 27 are provided with electrodes 26a and 27a for ignition.
are connected to each small capacity burner 23.
a and 23b are flame rods 2 that detect flames.
8 and 29 are provided.

30 is a control panel for controlling the electromagnetic on-off valves 10, 13, 17 and the blower 14;
36 is a pressure switch that operates at each level of gas pressure on the discharge side of the strainer 2, the pressure switch 31 sets the lowest gas pressure (for example, 50 mmAq), and the pressure switch 32 operates on the small capacity burner 23a,
The lower limit gas pressure required for the combustion operation of 23b (e.g.
The pressure switch 33 is used to set the lower limit gas pressure (for example, 150 mmAq) necessary for the combustion operation of the large capacity burners 24a and 24b. Further, the pressure switch 34 sets the upper limit gas pressure (for example, 350 mmAq) for the combustion operation of the small capacity burners 23a, 23b, and the pressure switch 35 sets the upper limit gas pressure (for example, 400 mmAq) for the combustion operation of the large capacity burners 24a, 24b. ), and the pressure switch 36 sets the maximum gas pressure (e.g.
450mmAq). The ON signals for each of these pressure switches 31 to 36 are sent to the control panel 30.
It is now output to . Further, flame detection signals from the flame rods 28 and 29 are taken into the control panel 30.

A pressure switch 37 is operated by the pressure on the discharge side of the blower 14, and its ON signal is output to the control panel 30. 38 is a pressure gauge for measuring the discharge pressure of the strainer 2; 39 is the blower 1;
4 is a pressure gauge for measuring the discharge pressure, and 40 and 41 are pressure gauges for measuring the air pressure supplied to the first and second mixers 6 and 7.

FIG. 2 shows a specific control circuit of the control panel 30, in which (+) and (-) are DC control power supplies, 50 is a start/stop relay, and this relay is a start switch 5.
1. Control power supply (+) via stop switch 52;
(-), and an operation display lamp 53 is connected in parallel to the relay 50. 54 is a gas pressure lower limit alarm relay, 55 is a lower limit pressure operation relay for small capacity burners, 56 is a lower limit pressure operation relay for large capacity burners, 57 is an upper limit pressure operation relay for small capacity burners, and 58 is an upper limit pressure operation relay for large capacity burners. Operation relay, 5
9 is a gas pressure upper limit alarm relay, 60 is a blower 14
are set pressure operation relays, and each of these relays 54
-60 are connected in parallel to control power supplies (+) and (-) via the pressure switches 31-37 mentioned above. 50a is a self-holding contact of the relay 50.

61 is a blower control relay;
is a parallel circuit of the normally open contact 57a of the upper limit pressure operation relay 57 for the small capacity burner and the normally open contact 58a of the upper limit pressure operation relay 58 for the large capacity burner, the normally closed contact 54a of the lower limit alarm relay 54, and the above Normally closed contact 5 of lower limit pressure operation relay 55 for small capacity burner
It is connected between control power supplies (+) and (-) via 5a. 61a is its self-holding contact.

62 is a blower operation relay, manual contact 63a,
It is connected to the control power supply (+) and (-) via a manual/automatic changeover switch 63 having an automatic contact 63b,
The normally open contact 61b of the blower control relay 61 is connected in series to the automatic contact 63a.
Further, 62a is a self-holding contact, and 64 is a blower operation indicator lamp.

65a is an indicator lamp that displays the operation of the burners 23a and 24a, and 65b is also the burner 23b.
and 24b, and each indicator lamp 65a, 65b is connected to the selection switch 6.
6 to the control power supplies (+) and (-), and the indicator lamp 65b is connected to the burners 23b and 2.
The ignition relay 67 on the 4b side is connected in parallel. 68 is a pre-purge timer connected to the control power supplies (+) and (-), 69 is an operation command relay for the large-capacity burner electromagnetic on-off valve 13 and the blower electromagnetic on-off valve 17; Normally open contact 58a of upper limit pressure operation relay 58 for use and normally closed contact 56a of lower limit pressure operation relay 56 for large capacity burner
It is connected to the control power supply (+) and (-) via. 69a is its self-holding contact. Reference numeral 70 denotes a start/stop relay for manually operating the large capacity burner, and this relay 70 is connected to control power sources (+) and (-) via a start switch 71 and a stop switch 72. 70a is its self-holding contact.

73 is an IC circuit that controls the ignition transformers 26, 27 and the electromagnetic on-off valves 10, 13, 14, the common terminal 73a of which is connected to the control power supply (+), and the input terminal 73b connected to the timer operation contact 68a of the timer 68. and the blower setting pressure operation relay 60
It is connected to the control power supply (+) via the normally open contact 60a. Output terminal 73c of the above IC circuit 73
A misfire detection relay 74 and its indicator lamp 75 are connected in parallel between the output terminal 73d and the control power source (-), and switching contacts 67a and 67b of the ignition relay 67 are connected between the output terminal 73d and the control power source (-). Ignition transformers 26 and 27 are connected in parallel. Further, an electromagnetic on-off valve 10 of the small capacity burner and its operation indicator lamp 76 are connected in parallel between the output terminal 73e of the IC circuit 73 and the control power source (-). Furthermore, the output terminal 7 of the IC circuit 73
3f and the control power supply (-) are the normally open contact 69a of the operation command relay 69 and the manual operation relay 7.
The electromagnetic on-off valves 13 and 17 which are energized by the closing of the normally open contact 70b and their operation display lamp 77
are connected in parallel. 78 is the normally open contact 54b of the lower limit alarm relay 54 and the upper limit alarm relay 5
An indicator lamp for gas pressure abnormality that lights up when the normally open contact 54b of 9 is closed; 79 is the lower limit alarm relay 5 mentioned above;
Normally open contact 54c of No. 4, normally open contact 59c of upper limit alarm relay 59, and normally open contact 6 of operation command relay 69.
9a is an alarm buzzer that operates when any one of the normally open contacts 69c is closed; 80 is a reset relay; this relay 80 is energized when the push button switch 81 is turned on, and the circuit of the buzzer 79 is activated; It is designed to be reset by opening the normally open contact 80a.

Next, the operation of this embodiment configured as described above will be explained.

When automatically operating a waste gas combustion device, first,
The automatic/manual changeover switch 63 is connected to the automatic contact 63b.
Then, the selection switch 66 is set to the state shown in FIG. 2 to select the small capacity burner 23a and the large capacity burner 24a for the No. 1 furnace. As a result, the indicator lamp 65a for the No. 1 furnace lights up when the power is turned on, indicating that the small capacity burner 23a and the large capacity burner 24a have been selected for combustion operation.

Next, the switching valves 20 and 25 are operated to switch between the small capacity burner 23a and the large capacity burner 24a on the No. 1 furnace side.
are both connected to the discharge sides of mixers 6 and 7. Then, the pre-purge timer 68 is set to, for example, 10 to 60 seconds.

In this state, a power switch (not shown) is turned on, and then the on-off valves 3 and 4 are slowly opened. Then, the waste gas cleaned by the scrubber 1 is sent under pressure to the strainer 2 via the on-off valves 3 and 4, where water and foreign matter contained in the waste gas are removed, and then the waste gas is sent under pressure to the burner side. At this time, the pressure of the waste gas is confirmed using the pressure gauge 38.

After going through these preparatory steps, start switch 5
1 and energizes the relay 50. This relay 50 is self-held by its contacts 50a, and a lamp 53 lights up to indicate that it is in an operating state, and further, when its contacts 50b are closed, the control power supply circuit is closed.

At this time, if the pressure of the waste gas is higher than the operating point of the pressure switch 34 (350 mmAq or higher shown in Figure 3) (at this time, the pressure switches 31 to 33 are off), the upper limit pressure for the small capacity burner is Since the operation relay 57 is energized, the blower control relay 61 is energized by the closing of the contact 57a, and the blower operation relay 62 is energized by the closing of the contact 61a, and the blower 14 is started. , the lamp 64 is also lit.

On the other hand, when the blower 14 is started and its discharge air pressure reaches the value set by the pressure switch 37, the pressure switch 37 is turned on, the set pressure operation relay 60 is energized, and its normally open contact 60a is closed. .

On the other hand, since the IC circuit operates with the closing of the control power supply circuit, the electromagnetic on-off valve 10 is excited, which opens the electromagnetic on-off valve 10 and supplies the waste gas discharged from the strainer 2 to the first mixer 6. After mixing with the air that is force-fed from the blower 14 to the mixer 6 through the flow meter 15 and the flow rate adjustment valve 16, it is supplied from the discharge port of the mixer 6 to the small capacity burner 23a of the No. 1 furnace. And the small capacity burner 23a
When the pre-purging time has elapsed, that is, the time limit set by the timer 68 has elapsed, the timed operation contact 68 turns on, thereby giving an ignition command to the IC circuit 73 and at the same time causing current to flow through the ignition transformer 26. , a spark discharge is generated between the electrode 26a and the burner 23a to ignite the small capacity burner 23a. At the same time as the burner 23a is ignited, the flow rate regulating valve 16 is operated to adjust the air-gas mixture ratio to a complete combustion state. After that, the condition of the flame will be checked and adjusted from time to time.

In the combustion state of only the small capacity burner 23a, when the amount of waste gas discharged from the waste treatment process increases and the gas pressure on the discharge side of the strainer 2 increases to 350 mmAq or more as shown in Fig. 3,
The pressure switch 58 is turned on, the large capacity burner upper limit pressure operation relay 58 is energized, and its contact 58b is closed, so that the solenoid valve operation command relay 69 is activated.
is energized. This relay 69 has its contact 69a
Since the contact 69b is closed, the electromagnetic on-off valves 13 and 17 are energized, and the contact 69b is closed.
Open each valve 13, 17. Therefore, the waste gas from the strainer 2 is supplied to the second mixer 7 through the electromagnetic on-off valve 13, and the air from the blower 14 is further supplied to the second mixer 7 through the electromagnetic on-off valve 17, where the two are mixed. After that, it is supplied to the large capacity burner 24a via the switching valve 25,
The combustion flame of the small capacity burner 23a ignites the waste gas, and the waste gas is also combusted in the large capacity burner 24a. The air-gas mixture ratio at this time is adjusted by the flow rate adjustment valve 18.

Further, when the pressure on the discharge side of the strainer 2 becomes 150 mmAq or less as shown in FIG. 3, the pressure switch 33 is turned on and the large capacity burner lower limit pressure operation relay 56 is energized. Therefore, when the normally closed contact 56a is opened, the operation command relay 69 is deenergized, and at the same time, the electromagnetic on-off valves 13 and 17 are also deenergized to stop the supply of waste gas and air to the mixer 7. Therefore, combustion by the large capacity burner 24a is also stopped. Furthermore, when the gas pressure on the discharge side of the strainer 2 decreases to 100 mmAq as shown in FIG. It will be released. Therefore, the blower control relay 61 is deenergized, and the blower operation relay 62 is also deenergized, so that the blower 14 is stopped.

That is, if the generated waste gas pressure changes as indicated by broken line I in FIG.
5 is activated, and depending on the amount of waste gas generated, only the small capacity burner 23a or the small capacity burner 23a and the large capacity burner 24a are operated for combustion, and combustion that matches the amount of waste gas can be automatically carried out. can. Further, when the stop switch 52 is pressed, the relay 50 is deenergized and the power supply to the control circuit is cut off, so that the combustion apparatus is stopped.

FIG. 4 shows a time chart from start to stop of the above-mentioned combustion device.

Next, a case will be described in which the combustion device is operated manually.

In this case, first, the changeover switch 63 is switched to the manual contact 63a side.

Thereafter, after performing the preparation settings in the same manner as in the automatic operation described above, if the start switch 51 is pressed, the same control as described above will be performed. However, the difference from automatic operation is that when the start switch 71 that operates the large-capacity burner is turned on, the relay 70 is energized, the electromagnetic on-off valves 13 and 17 are opened, and the large-capacity burner 24a is activated.
The gas and air will be supplied to the combustion chamber for combustion. Also, if you press the stop switch 72, the large capacity burner 2
4a will stop combustion.

In addition, when operating the small capacity burner 23b and large capacity burner 24b on the No. 2 furnace side, it is sufficient to switch the selection switch 66 and keep the relay 67 in the energized state.

Next, the operation of abnormal gas pressure will be described.

The gas pressure on the discharge side of strainer 2 is 50 as shown in Figure 3.
When it becomes less than mmAq, the pressure switch 31 is turned on,
As a result, the lower limit alarm relay 54 is energized, its normally closed contact 54a opens, and its normally open contacts 54b, 54
c is closed. When the normally open contact 54b closes, the indicator lamp 78 lights up to indicate the gas pressure abnormality, and at the same time, the normally open contact 54c closes, causing the buzzer 79 to sound to notify the gas pressure abnormality.

Further, when the gas pressure on the discharge side of the strainer 2 exceeds 450 mmAq shown in FIG. 3, the pressure switch 36 is turned on and the upper limit alarm relay 59 is energized. As a result, the normally open contact 59a is closed, so the lamp 78 lights up to visually indicate that a gas pressure abnormality has occurred, and the normally open contact 59 is closed, causing the buzzer 79 to sound. Notifies abnormal gas pressure with sound.

Further, in the abnormality notification state, if the push button switch 81 is pressed, the relay 80 is energized, and the buzzer 79 is stopped by opening the contact 80a. And if the gas pressure is 50mmAq or more as shown in Figure 3,
Alternatively, if the normal state returns to 450 mmAq or less, combustion control operation will automatically resume. In particular, when the gas pressure is high, the gas is combusted, but if it is not completely combusted, it is released into the atmosphere.

In the above embodiment, a case was described in which the waste gas combustion burner was configured with two burners of small capacity and large capacity, but it may be configured with two or more burners, and the number of sets may be two. It is not limited. Although a flame rod was used as the flame detection means, a phototube method may also be used. Further, the mixers 6 and 7 may be of a push-in type. Furthermore, various relays may be of explosion-proof type as required.

(F) Effects of the Invention As explained above, according to the present invention, even if the amount, pressure, and composition of waste gas change, combustion control suitable for combustion can be performed, and as a result, the amount of waste gas contained in the waste gas can be controlled. It can completely burn combustible gases, toxic gases, and other gases, eliminating danger and preventing air pollution. It also has the advantage of being able to be used as a heat source for a heating furnace in the waste treatment process.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an example of the waste gas combustion apparatus of the present invention, Fig. 2 is a wiring diagram of the combustion control circuit in the present invention, and Fig. 3 shows the relationship between the waste gas pressure and burner combustion operation in the present invention. The explanatory diagram shown in FIG. 4 is also a time chart for explaining the operation of the combustion apparatus in the present invention. 1...Scrubber, 2...Strainer, 5,15
...Flowmeter, 6,7...Mixer, 9,12...Zero governor, 10,13,19...Solenoid shut-off valve, 1
6, 18...Flow rate adjustment valve, 14...Blower, 2
0, 25...Switching valve, 23a, 23b...Small capacity burner, 24a, 24b...Large capacity burner, 2
6, 27... Ignition transformer, 28, 29... Flame rod, 30... Control panel, 31-37... Pressure switch.

Claims (1)

[Claims] 1. At least one burner mechanism formed by combining a plurality of burners with different combustion capacities, a mixer that is separately provided corresponding to each burner of the burner mechanism and mixes waste gas and air, and a mixer that mixes waste gas and air; an air flow rate adjustment valve that is installed in a passage connecting each of the mixers and the blower to properly set the mixing ratio with the waste gas, and a solenoid valve that opens and closes the passage; A zero governor provided in a passage connecting the mixers, a solenoid valve for opening and closing the passage, a means for detecting the waste gas supply pressure, a means for detecting the supply air pressure of the blower, and a solenoid valve for opening and closing the passage. control means for controlling the opening and closing of the electromagnetic valve based on a signal corresponding to a gas pressure level and a signal from the air pressure detection means and selecting a burner of the burner mechanism according to the supplied waste gas pressure; and an ignition means for the burner mechanism. A waste gas combustion device characterized by comprising: