Safety interlocking system for recycling DMAC (dimethylacetamide) in spandex spinning

Abstract

A safety interlocking system for recycling spandex spinning DMAC (dimethylacetamide) comprises a DCS (distributed control system) control cabinet and a stock solution header pipe, the DCS control cabinet is used for receiving signals of an alarm and sending control signals, a stock solution booster pump is arranged at the input end of the stock solution header pipe, and the stock solution header pipe is connected with a spinning channel through a stock solution metering pump; the spinning channel is connected with an air inlet header pipe and an air return header pipe, the air inlet header pipe and the air return header pipe are connected through a DMAC recovery device, and an air inlet pressure alarm is arranged at the tail of the air inlet header pipe. The DMAC recovery device comprises a heat pipe heat exchanger, a recovery fan and a condenser connected with the recovery fan, the heat pipe heat exchanger comprises a heat exchanger hot side and a heat exchanger cold side, a recovery fan abnormity alarm is arranged on the recovery fan, and a heat exchanger inlet temperature alarm is arranged between the heat exchanger cold side and the recovery fan. When any point of the air inlet pressure alarm, the heat exchanger inlet temperature alarm and the first heater outlet temperature alarm is abnormal, the stock solution booster pump, the stock solution metering pump and the second heater can be stopped, and safety is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model belongs to spandex spinning equipment technical field, specifically point to a kind of spandex spinning DMAC recovery's safety interlocking system. BACKGROUND

[0002] Spandex spinning dry process is in dry environment, using specific equipment to dissolve prepolymer in solvent DMAC, forms spinning stock solution. After processing, the stock solution is sprayed from spinneret hole to form filament long flow, in spinning duct, solvent is volatilized by hot air, then filament solidifies and stretches and refines, and finally is wound into spandex cake.

[0003] DMAC is dimethylacetamide, DMAC in spinning duct has the possibility of explosion when its content in air is greater than 1.8% at temperature exceeding 200℃. The safety measures taken in the industry are to interlock the start and stop of stock solution metering pump and stock solution booster pump according to the state of DMAC recovery fan. But the safety measures still have the following risks: 1. When the temperature of hot return air after cooling by heat pipe heat exchanger and condenser is high, it means that the DMAC recovery rate is low, and DMAC is not recovered in time, so the content of DMAC in the spinning duct will increase; 2. The hot return air after cooling needs to be heated by heat pipe heat exchanger and first heater, and the first heater is steam heating. When the steam heating is abnormal, the temperature of hot air at the outlet of the first heater is too low, which will reduce the volatilization speed of DMAC in the spandex filament in the spinning duct, and the spandex filament containing DMAC is easy to burn and explode in the spinning duct; 3. When the air supply pressure of DMAC recovery fan is insufficient, DMAC in the spinning duct cannot be effectively returned to the recovery device for recovery, and a large amount of DMAC will be left, which will increase the content of DMAC in the spinning duct; 4. The second heater is installed in the air inlet pipeline on the spinning duct for fine adjustment of the temperature of hot inlet air, and the second heater uses electric heating. When the DMAC recovery fan stops abnormally, there is no air flow in the upper air inlet pipeline, which will cause the temperature in the second heater to rise sharply and be damaged. SUMMARY

[0004] The technical problem to be solved by the utility model is to design a safety interlocking system for spandex spinning DMAC recovery, which can interlock the stop of stock solution booster pump, stock solution metering pump and second heater when the temperature of condenser after condensation is high, the temperature of first heater after heating is low and the DMAC recovery fan is abnormal, to ensure the safety of personnel and equipment.

[0005] The utility model is implemented as follows:

[0006] A safety interlocking system for DMAC recovery of spandex spinning includes a DCS system control cabinet receiving an alarm signal and sending a control signal to a device, a total solution pipe conveying a DMAC spinning solution, a solution booster pump arranged at an input end of the total solution pipe, and a solution metering pump connecting the total solution pipe with a spinning duct.

[0007] A top of the spinning duct is connected with an air inlet total pipe and an air return total pipe, and a bottom of the spinning duct is connected with the air return total pipe, the air inlet total pipe and the air return total pipe are connected through a DMAC recovery device to form a hot air circulation loop, and an air inlet pressure alarm is arranged at a tail of the air inlet total pipe.

[0008] The DMAC recovery device includes a heat pipe heat exchanger, a recovery air blower supplying air to the air inlet total pipe, and a condenser connected with an input end of the recovery air blower, the heat pipe heat exchanger includes a heat exchanger hot side connecting the condenser and the air return total pipe, and a heat exchanger cold side connecting an output end of the recovery air blower and the air inlet total pipe, an abnormal recovery air blower alarm is arranged on the recovery air blower, and a heat exchanger inlet temperature alarm is arranged between the heat exchanger cold side and the recovery air blower.

[0009] The solution booster pump, the solution metering pump, the air inlet pressure alarm, and the heat exchanger inlet temperature alarm are respectively connected to the DCS system control cabinet through signal lines.

[0010] Further, a first heater is arranged between the heat exchanger cold side and the air inlet total pipe, a first heater outlet temperature alarm is further arranged between the first heater and the air inlet total pipe, and the first heater outlet temperature alarm is connected to the DCS system control cabinet through a signal line.

[0011] Further, a top of the spinning duct is connected with the air inlet total pipe through an upper air inlet pipe, the top and the bottom of the spinning duct are respectively connected with the air return total pipe through an upper air return pipe and a lower air return pipe, and a second heater is arranged on the upper air inlet pipe, and the second heater is connected to the DCS system control cabinet through a signal line.

[0012] Further, the DMAC recovery device further includes a DMAC collection tank connected to the condenser and the heat pipe heat exchanger through a first collection pipeline.

[0013] Furthermore, it also includes an exhaust gas treatment device, which includes an exhaust gas fan and an exhaust gas condenser connected to the input end of the exhaust gas fan. The exhaust gas fan is equipped with an exhaust gas fan malfunction alarm. The exhaust gas condenser is connected to the bottom of the spinning tunnel through an exhaust gas inlet pipe. The output end of the exhaust gas fan is connected to the return air main pipe through an exhaust gas outlet pipe. The exhaust gas condenser is connected to the DMAC recovery device through a second collection pipe. The exhaust gas fan and the exhaust gas fan malfunction alarm are connected to the DCS system control cabinet through signal lines.

[0014] Furthermore, a spraying device is provided inside the heat pipe heat exchanger hot side, the condenser, and the exhaust gas condenser.

[0015] Furthermore, a backup recovery fan is provided near the recovery fan, and a backup recovery fan malfunction alarm is provided on it; a backup exhaust fan is provided near the exhaust fan, and a backup exhaust fan malfunction alarm is provided on it.

[0016] The standby recovery fan, the standby recovery fan malfunction alarm, the standby exhaust fan, and the standby exhaust fan malfunction alarm are connected to the DCS system control cabinet via signal lines.

[0017] The advantages of this invention are as follows: When any of the following alarms—the inlet air pressure alarm, the heat exchanger inlet temperature alarm, and the first heater outlet temperature alarm—detects an abnormality, the raw material booster pump, the raw material metering pump, and the second heater can be stopped in a chain reaction, preventing the DMAC content in the spinning tunnel and the temperature of the second heater from continuing to rise, thus ensuring the safety of personnel and equipment; The addition of a tail gas treatment device reduces the diffusion of DMAC from the spinning tunnel to the outside during production, and the device remains open during shutdown to continuously reduce the DMAC content in the spinning tunnel, further enhancing safety; the addition of spray devices to the hot side of the heat exchanger, the condenser, and the tail gas condenser increases the cooling rate of the hot return air and the rate at which DMAC condensate separates from the hot air circulation loop; and the adoption of a backup fan and backup alarm design allows for automatic switching to a backup fan and backup alarm when the fan fails, reducing production line downtime, increasing production line uptime, and ensuring stable production capacity. Attached Figure Description

[0018] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a layout diagram of the safety interlocking system of this utility model.

[0020] Figure 2 This is a layout diagram of the safety interlocking system of this utility model (with hidden signal lines).

[0021] Reference signs:

[0022] 1-DCS system control cabinet, 2-raw solution main pipe, 21-raw solution booster pump, 22-raw solution metering pump, 3-spinning duct, 31-silk outlet, 32-upper air inlet pipe, 321-second heater, 33-upper air return pipe, 34-lower air return pipe, 4-air inlet main pipe, 41-air inlet pressure alarm, 42-heat exchanger inlet temperature alarm, 43-first heater, 44-first heater outlet temperature alarm, 5-air return main pipe, 61-recovery air fan, 611-recovery air fan abnormality alarm, 62-heat pipe heat exchanger, 621-heat exchanger hot side, 622-heat exchanger cold side, 63-condenser, 64-DMAC collection tank, 641-first collection pipe, 642-second collection pipe, 71-tail gas fan, 711-tail gas fan abnormality alarm, 72-tail gas condenser, 73-tail gas inlet pipe, 74-tail gas outlet pipe, 8-spraying device. DETAILED DESCRIPTION

[0023] The embodiments of the utility model are specifically explained below. Figure 1 、 Figure 2 The embodiments of the utility model are specifically explained below.

[0024] A safety interlocking system for spandex spinning DMAC recovery, the safety interlocking system comprises: a DCS system control cabinet 1 receiving alarm signals and sending control signals to equipment, a raw solution main pipe 2 conveying DMAC-containing spinning raw solution, a raw solution booster pump 21 arranged at the input end of the raw solution main pipe 2, and a raw solution metering pump 22 connecting the raw solution main pipe 2 with a spinning duct 3, wherein the spinning duct 3 is a vertical passage arranged from top to bottom, the top of the spinning duct 3 is connected with an air inlet main pipe 4 and an air return main pipe 5, the bottom of the spinning duct 3 is connected with the air return main pipe 5, and a silk outlet 31 is arranged at the bottom of the spinning duct 3 for conveying the formed spandex silk outside, and the air inlet main pipe 4 and the air return main pipe 5 are connected through a DMAC recovery device to form a hot air circulation loop; the raw solution booster pump 21 and the raw solution metering pump 22 are respectively connected to the DCS system control cabinet 1 through signal lines.

[0025] The DMAC recovery device comprises: a recovery air fan 61, three groups of heat pipe heat exchangers 62, two groups of condensers 63 and a DMAC collection tank 64, the recovery air fan 61 supplies air for the air inlet main pipe 4, a recovery air fan abnormality alarm 611 is arranged on the recovery air fan 61, and an air inlet pressure alarm 41 is arranged at the tail part of the air inlet main pipe 4; the recovery air fan 61, the recovery air fan abnormality alarm 611 and the air inlet pressure alarm 41 are respectively connected to the DCS system control cabinet 1 through signal lines.

[0026] The three groups of heat pipe heat exchangers 62 are connected in series, the heat pipe heat exchanger 62 comprises a heat exchanger hot side 621 and a heat exchanger cold side 622, the heat exchanger hot side 621 is connected with the return air main pipe 5, the output end of the recovery air fan 61 is connected with the air inlet main pipe 4 through the heat exchanger cold side 622, the working medium of the heat exchanger hot side 621 is heated by the return air and then migrates to the heat exchanger cold side 622, the heated working medium is cooled by the inlet air in the heat exchanger cold side 622 and then migrates back to the heat exchanger hot side 621, and the heat exchange is circulated. Two groups of condensers 63 are connected in series, the heat exchanger hot side 621 is connected with the input end of the recovery air fan 61 through the condenser 63. There is a partition between the cold side and the hot side of the heat pipe heat exchanger 62, only the working medium can migrate back and forth, the hot return air of the return air main pipe 5 can only pass through the heat exchanger hot side 621 and enter the condenser 63 and cannot enter the heat exchanger cold side 622, and the hot inlet air of the output end of the recovery air fan 61 can only pass through the heat exchanger cold side 622 and enter the air inlet main pipe 4 and cannot enter the heat exchanger hot side 621. The DMAC collecting box 64 is connected with the heat exchanger hot side 621 and the condenser 63 through the first collecting pipe 641.

[0027] A heat exchanger inlet temperature alarm 42 is arranged between the recovery air fan 61 and the heat exchanger cold side 622, a first heater 43 is arranged between the air inlet main pipe 4 and the heat exchanger cold side 622, the first heater 43 is a steam heater and is used for coarsely adjusting the inlet air temperature, and a first heater outlet temperature alarm 44 is further arranged between the first heater 43 and the air inlet main pipe 4; the heat exchanger inlet temperature alarm 42 and the first heater outlet temperature alarm 44 are respectively connected to the DCS system control cabinet 1 through signal lines.

[0028] The top of the spinning duct 3 is connected with the air inlet main pipe 4 through an upper air inlet pipe 32, a second heater 321 is arranged on the upper air inlet pipe 32, the second heater 321 is an electric heater and is used for finely adjusting the inlet air temperature, the top of the spinning duct 3 is connected with the return air main pipe 5 through an upper return air pipe 33, and the bottom of the spinning duct 3 is connected with the return air main pipe 5 through a lower return air pipe 34; the second heater 321 is connected to the DCS system control cabinet 1 through a signal line.

[0029] The safety interlocking system further comprises a tail gas treatment device, the tail gas treatment device comprising a tail gas fan 71 and a tail gas condenser 72 connected to an input end of the tail gas fan 71, the tail gas fan 71 being provided with a tail gas fan abnormality alarm 711, the tail gas condenser 72 being connected to the bottom of the spinning duct 3 through a tail gas inlet pipe 73, an output end of the tail gas fan 71 being connected to the air return main pipe 5 through a tail gas outlet pipe 74, and the DMAC collection tank 74 being connected to the tail gas condenser 72 through a second collection pipe 642. Since the spinning port 31 at the bottom of the spinning duct 3 is communicated with the outside, the tail gas treatment device can reduce the diffusion of DMAC to the outside by performing air extraction on the bottom of the spinning duct 3 and condensing the tail gas, and can continuously reduce the concentration of DMAC in the spinning duct 3 by keeping the tail gas treatment device open when the equipment is stopped. If DMAC diffuses to the outside in large quantities, there is a risk of environmental pollution and explosion.

[0030] The safety interlocking system can further comprise a standby recovery fan and a standby tail gas fan (not shown in the figure) near the recovery fan and the tail gas fan, and the standby recovery fan and the standby tail gas fan are respectively provided with a standby recovery fan abnormality alarm and a standby tail gas fan abnormality alarm (not shown in the figure). The above-mentioned fans and alarms are respectively connected to the DCS system control cabinet 1 through signal lines. When the recovery fan 61 and the tail gas fan 71 are abnormal, the standby fans can be automatically started, and the abnormal fans can be stopped. During the periodic maintenance of the production line, the abnormal fans can be repaired together, which can reduce the downtime of the production line. The standby fans can be arranged before or after the existing fans in the existing air pipes, or can be arranged in the additional bypass air pipes.

[0031] Spraying devices 8 are arranged in the heat side 621 of the heat exchanger, the condenser 63 and the tail gas condenser 72. The spraying liquid is chilled water, which is used to increase the cooling rate of the hot return air, to flush the heat side 621 of the heat pipe heat exchanger, the condenser 63 and the tail gas condenser 72, and to flush the condensed DMAC into the DMAC collection tank 64 in time to separate from the hot air circulation loop.

[0032] Working principle of the safety interlocking system:

[0033] (1) No standby fan and standby alarm are installed

[0034] Scenario 1: When the recovery fan abnormality alarm 611 finds that the recovery fan 61 is abnormal, such as the fan current returning to zero or the current greatly decreasing, it indicates that the recovery fan 61 is stopped, the power supply voltage is decreased or there is other fault. The recovery fan abnormality alarm 611 sends a fault signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22 and the second heater 321 through signal lines to ensure that the spinning production is stopped.

[0035] Scenario 2: When the tail gas fan abnormality alarm 711 finds that the tail gas fan 71 is abnormal, such as the fan current returning to zero or a significant drop in current, indicating that the tail gas fan 61 has stopped, the power supply voltage has dropped, or there is other failure, the tail gas fan abnormality alarm 711 sends a fault signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22, and the second heater 321 through signal lines to ensure that the spinning production stops.

[0036] Scenario 3: When the inlet air pressure alarm 41 finds that the air pressure at the tail of the inlet air main is abnormal, such as a significant drop in air pressure or failure to detect air pressure, indicating that the recovery fan 61 has stopped, the power supply voltage has dropped, causing the recovery fan 61 to run at low speed, or there is other failure, the inlet air pressure alarm 41 sends an air pressure signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22, and the second heater 321 through signal lines to ensure that the spinning production stops.

[0037] Scenario 4: When the heat exchanger inlet temperature alarm 42 finds that the heat exchanger inlet temperature is high (greater than 20℃), indicating that the DMAC recovery rate is low, DMAC has not been recovered in time, and it may be due to abnormality of the condenser 63, the first heater 43, or the second heater 321, etc. The heat exchanger inlet temperature alarm 42 sends a high temperature signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22, and the second heater 321 through signal lines to ensure that the spinning production stops.

[0038] Scenario 5: When the first heater outlet temperature alarm 44 finds that the first heater 44 outlet temperature is low (less than 230℃), it may be due to insufficient steam temperature, a decrease in steam flow, or a too low condenser temperature. The first heater outlet temperature alarm 44 sends a low temperature signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22, and the second heater 321 through signal lines to ensure that the spinning production stops.

[0039] (2) Installation of backup fans and backup alarms

[0040] The safety interlocking system is installed with a backup recovery fan, a backup tail gas fan, a backup recovery fan abnormality alarm, and a backup tail gas fan abnormality alarm.

[0041] Scenario 6: When the recycling fan abnormality alarm 611 finds that the recycling fan 61 is abnormal, such as the fan current returning to zero or a large decrease in current, indicating that the recycling fan 61 is stopped, the power supply voltage is decreased, or there is other failure, the recycling fan abnormality alarm 611 sends a failure signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 sends a control signal to start the standby recycling fan and the standby recycling fan abnormality alarm through the signal line, and simultaneously stops the recycling fan 61 and the recycling fan abnormality alarm 611, if the standby recycling fan abnormality alarm alarms again during production, the standby recycling fan abnormality alarm sends a failure signal to the DCS system control cabinet 1, and the DCS system control cabinet simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22 and the second heater 321 through the signal line, to ensure that the spinning production is stopped.

[0042] Scenario 7: When the tail gas fan abnormality alarm 711 finds that the tail gas fan 71 is abnormal, such as the fan current returning to zero or a large decrease in current, indicating that the tail gas fan 71 is stopped, the power supply voltage is decreased, or there is other failure, the tail gas fan abnormality alarm 611 sends a failure signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 sends a control signal to start the standby tail gas fan and the standby tail gas abnormality alarm through the signal line, and simultaneously stops the tail gas fan 71 and the tail gas fan abnormality alarm 711, if the standby tail gas fan abnormality alarm alarms again during production, the standby tail gas fan abnormality alarm sends a failure signal to the DCS system control cabinet 1, and the DCS system control cabinet 1 simultaneously closes the original liquid booster pump 21, the original liquid metering pump 22 and the second heater 321 through the signal line, to ensure that the spinning production is stopped.

[0043] The utility model discloses when any one of the air inlet pressure alarm, the heat exchanger import temperature alarm, first heater export temperature alarm detects the abnormality, can interlock and stop the original liquid booster pump, the original liquid metering pump and the second heater, avoid the DMAC content in the spinning flue and the second heater temperature continue to rise, guarantee personnel equipment safety, because additionally adds the tail gas treatment device, can reduce the DMAC diffusion in the spinning flue to the outside during production, and simultaneously when stopping, the tail gas treatment device keeps open and can continuously reduce the DMAC content in the spinning flue, further improve the security, because the spraying device has been added in the heat exchanger hot side, condenser, tail gas condenser, can increase the cooling rate of the hot return air and the rate of DMAC condensate from the hot air circulation loop, because the standby fan, standby alarm design is adopted, when the fan failure, can automatically switch to standby fan and standby alarm, can reduce the production line downtime, increase the production line start-up rate, guarantee the stability of the production capacity.

[0044] The above embodiments and drawings are not limited to the product shape and style of the present application, and any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the scope of the present application.

Claims

1. A safety interlock system for spandex spinning DMAC recovery, characterized by: The application relates to a DCS system control cabinet receiving an alarm signal and sending a control signal to a device, a spinning solution main pipe containing a DMAC spinning solution, a spinning solution booster pump arranged at the input end of the spinning solution main pipe, and a spinning duct connected with the spinning solution main pipe through a spinning solution metering pump. The top of the spinning duct is connected with an air inlet main pipe and an air return main pipe, the bottom of the spinning duct is connected with the air return main pipe, the air inlet main pipe is connected with the air return main pipe through a DMAC recovery device to form a hot air circulation loop, and an air inlet pressure alarm is arranged at the tail of the air inlet main pipe. The DMAC recovery device comprises a heat pipe heat exchanger, a recovery air blower for supplying air to the air inlet main pipe, and a condenser connected with the input end of the recovery air blower, the heat pipe heat exchanger comprises a heat exchanger hot side connecting the condenser and the air return main pipe and a heat exchanger cold side connecting the output end of the recovery air blower and the air inlet main pipe, an abnormal recovery air blower alarm is arranged on the recovery air blower, and a heat exchanger inlet temperature alarm is arranged between the heat exchanger cold side and the recovery air blower. The spinning solution booster pump, the spinning solution metering pump, the air inlet pressure alarm and the heat exchanger inlet temperature alarm are respectively connected with the DCS system control cabinet through signal lines. A first heater is arranged between the heat exchanger cold side and the air inlet main pipe, and a first heater outlet temperature alarm is further arranged between the first heater and the air inlet main pipe, and the first heater outlet temperature alarm is connected with the DCS system control cabinet through a signal line.

2. A safety interlock system for spandex spinning DMAC recovery as claimed in claim 1, wherein: The top of the spinning duct is connected with the air inlet main pipe through an upper air inlet pipe, the top and bottom of the spinning duct are respectively connected with the air return main pipe through an upper air return pipe and a lower air return pipe, and a second heater is arranged on the upper air inlet pipe; and the second heater is connected with the DCS system control cabinet through a signal line.

3. A safety interlock system for spandex spinning DMAC recovery as claimed in claim 2, wherein: The DMAC recovery device further comprises a DMAC collection tank connected with the condenser and the heat pipe heat exchanger through first collection pipelines.

4. A safety interlock system for DMAC recovery of spandex spinning as claimed in claim 1, wherein: The application further relates to a tail gas treatment device, which comprises a tail gas blower and a tail gas condenser connected with the input end of the tail gas blower, an abnormal tail gas blower alarm is arranged on the tail gas blower, the tail gas condenser is connected with the bottom of the spinning duct through a tail gas inlet pipe, the output end of the tail gas blower is connected with the air return main pipe through a tail gas outlet pipe, the tail gas condenser is connected with the DMAC recovery device through second collection pipelines, and the tail gas blower and the abnormal tail gas blower alarm are connected with the DCS system control cabinet through signal lines.

5. A safety interlock system for spandex spinning DMAC recovery as claimed in claim 4 wherein: Spraying devices are arranged in the heat pipe heat exchanger hot side, the condenser and the tail gas condenser.

6. A safety interlock system for spandex spinning DMAC recovery as claimed in claim 5 wherein: A standby recovery air blower is arranged near the recovery air blower, an abnormal standby recovery air blower alarm is arranged on the standby recovery air blower, a standby tail gas blower is arranged near the tail gas blower, and an abnormal standby tail gas blower alarm is arranged on the standby tail gas blower; 7. A safety interlock system for spandex spinning DMAC recovery as claimed in claim 5 wherein: The standby recovery air blower, the abnormal standby recovery air blower alarm, the standby tail gas blower and the abnormal standby tail gas blower alarm are connected with the DCS system control cabinet through signal lines. ​

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