CN2462439Y - Multifunctional oil tank gas recovering and frequency converting control cabinet - Google Patents

Abstract

The utility model relates to a multifunctional oil tank gas recovering and frequency changing control cabinet, which is composed of a frequency changing speed regulator (5), a PID regulator (3), a PLC programmable logical controller (4), an electric control line (6), a safety grid (2), and a micro difference pressure transmitter (1). The utility model is characterized in that large tank pressure signals are converted into corresponding simulating electric signals by the micro difference pressure transmitter, and the electric signals are input into the PID regulator; after the calculation of the PID, the signals are sent out to the frequency changing speed regulator to control the rotary speed of a compressor. When gas quantity is changed, automatic circular start and stop and switching control can be carried out by the PLC logical controller. The control cabinet also comprises a combustible gas alarm, so that accidents caused by the leakage of natural gas pipelines can be avoided.

Description

Multi-functional oil tank gas reclaims the variable frequency control cabinet

This switch board belongs to the natural gas compressor automaton, is to be used for the opertaing device that tank deck oil tank gas reclaims automatically.Specifically, it is the rotating speed of controlling compressor according to the detected big jar of tank deck pressure of differential pressure transmitter, when tank deck pressure is higher, automatically accelerate the rotating speed of compressor, bleed more, when tank deck pressure is low, reduce the rotating speed of compressor automatically, bleed less, the multi-functional oil tank gas that tank deck pressure is remained stable reclaims the variable frequency control cabinet.

Originally oil field tank adopts opened type mostly, and the tank deck natural gas straight runs in and is put in the atmosphere, has both wasted the energy, has caused environmental pollution again.The recovery of oil tank gas at present has two kinds of schemes: the one, adopt the tank deck rock gas is caused in the big leather bag, and according to the gas charging degree of leather bag, the rotating speed of manual adjustments compressor, control rate of air sucked in required.Having drawback is that adjusting is untimely, and excessive bleeding easily makes the oil tank entrained air cause spontaneous combustion.The 2nd, oil tank is airtight, automatically regulate the rotating speed of compressor according to tank deck pressure, and carry out the loop start of several compressors, the independently developed electronic circuit logic controller of main employing, carry out the purpose that logic control reaches adjusting by tens relays, because electronic circuit and relay control fault rate height, when tolerance changes greatly, relay work relay misoperation frequently often occurs and makes abnormal situation of working.Scheme two patent No.s are ZL 95216036.6

The purpose of this utility model is that a kind of multi-functional oil tank gas that overcomes above oil tank gas control system device defect of design reclaims the variable frequency control cabinet.

Realize in the following manner on the technical solution of the utility model:

The utility model adopts formations such as variable-frequence governor 5, PID adjusting apparatus 3, PLC logic controller 4, complete electric control circuit 6, safety barrier 2, peripheral matched differential pressure transmitter 1.The technological means that the utility model adopts is as described below: differential pressure transmitter 1 converts big jar 7 tank deck pressure signals to 4～20mA electric signal, give PID adjusting apparatus 3, adjusting apparatus 3 compares according to the force value and the desired force value of actual measurement, its deviation is carried out the PID computing, output signal is given the rotating speed of frequency converter 5 control compressors.When the tolerance increase, the rotating speed that reaches upper pressure limit value and compressor reaches maximum speed, then this compressor is switched to power frequency operation, and starts another compressor converting operation; When tolerance reduced, the rotating speed that is lower than low pressure limit value and compressor reached minimum speed, then stopped the compressor of power frequency operation, only kept a converting operation, remained the tank deck constant pressure.All start and stop and change action logic are all controlled fully automatic operation by PLC logic controller 4.If frequency converter 5 goes wrong, switch board is taked the double site type control mode automatically, promptly utilizes tank deck pressure upper and lower limit to carry out the power frequency circulating start and outage of two compressors, guarantees the carrying out that produces.Comprise also in the switch board that flammable gas alarm 8 causes that to prevent that natural gas line leaks in the compressor plant accident takes place.

The utility model is compared with present oil tank gas recovery control device and is had the following advantages:

Working stability is reliable, regulates in time, and the relay logic control adopts the PLC Programmable Logic Controller to realize with the software programming mode, has overcome electronic circuit and the high drawback of relay control fault rate in the past, is a kind of follow-on oil tank gas recovering device.

For further disclosing the technical solution of the utility model,, elaborate by embodiment below in conjunction with Figure of description 1,2,3,4,5:

Accompanying drawing one is the electrical control block scheme

Accompanying drawing two is settings of PLC input, output point

Accompanying drawing three is variable-frequence governor control principle figure

Accompanying drawing four is major loop figure

Accompanying drawing five is electrical schematic diagrams

Details are as follows to the embodiment of this device in conjunction with the accompanying drawings:

In the accompanying drawing one, 1 is differential pressure transmitter, adopts U.S. ROSEMOUNT3051 series, 2 is safety barrier, adopts the female peaceful KN-9000 series zena's safety barrier in Shaanxi, and 3 is the PID adjusting apparatus, adopt day island proper electricity SR63 series, 4 is the PLC programmable logic controller (PLC), adopts Mitsubishi FXON-60MR, 5 is variable-frequence governor, adopt Japanese fuji FRN5000P11S, 6 is the circulating start and outage electric circuit, and 7 is big jar, 8 is flammable gas alarm, adopts Shenzhen Suo Futong SST-9601 series.

Accompanying drawing two is the PLC input, the facilities of output point and the electrical schematic diagram of input point, input, arranging of output point is as follows: X000 1# compressor start X001 1# compressor stops X002 2# compressor start X003 2# compressor and stops X004 frequency converter operation X005 1# compressor oil pressure fault X006 1# compressor hydraulic pressure fault X007 1# Compressor Discharge Pressure fault X010 2# compressor oil pressure fault X011 2# compressor hydraulic pressure fault X012 2# Compressor Discharge Pressure fault X013 frequency converter failure X014 frequency conversion and reach 50HZ signal X015 low pressure limit signal X016 upper pressure limit signal X017 mute button X020 1# and drop into/cut out X021 2# and drop into/cut out lower limit Y000 frequency converter run signal Y002 frequency conversion trouble light Y003 warning electric bell Y004 1# compressor variable frequency operation Y005 1# compressor power frequency operation Y006 2# compressor variable frequency operation Y007 2# compressor power frequency operation Y010 1# oil pressure trouble light Y011 2# oil pressure trouble light Y012 compressor hydraulic pressure trouble light Y013 Compressor Discharge Pressure trouble light Y014 compressor oil pressure trouble light Y015 1# compressor operating signal Y016 2# compressor operating signal Y017 output pump stop signal under the X022 pressure

Accompanying drawing three is the electric hookup of Frequency Converter Control terminal, and FWD, CM are frequency converter operation terminal, and 30A, 30C are frequency converter failure output, and C1,11 is the current signal input, and FMA, 11 is frequency output, and Y2, CME are that frequency reaches 50Hz output.

Accompanying drawing four is the major loop schematic diagram of whole system, and wherein QF1～QF3 is an air switch; KM1～KM4 is an A.C. contactor, and KM1 is 1# compressor variable frequency operation contactor, and KM2 is 2# compressor variable frequency operation contactor, and KM3 is a 1# compressor power frequency operation contactor, and KM4 is a 2# compressor power frequency operation contactor, and JZ1, JZ2 are oil pump operation contactor.

Accompanying drawing five is the control loop schematic diagram of whole system.

Safety barrier part 2 is accepted 4～20mA signal (PV signal) that differential pressure transmitter 1 is sent here, and after carrying out electrical isolation, exports PID adjusting apparatus 3 to.

PID adjusting apparatus part 3 is set and is kept big jar tank deck constant pressure value (SV signal) and report to the police and the tank deck pressure upper and lower limit of switching effect and threshold pression value down.The PV value and the set pressure SV value of reflection tank deck true pressure are compared, and P carries out the PID computing to its difference DELTA, and scale-up factor P gets 150, and I gets 40, and D is zero.4～20mA the current signal that draws after the computing is exported to variable-frequence governor 5.

PLC programmable logic controller (PLC) part 4 these parts are core of the present utility model, and the start and stop of all compressors and oil pump equipment and fault show to be finished by this part, utilizes the software programming mode to realize each function.

When big jar of tank deck pressure was higher than 450Pa, PLC accepted the last limited signal from the PID adjusting apparatus, started the operation of 1# compressor variable frequency automatically.When big jar tolerance constantly increases, 1# compressor 50Hz operation, when pressure still was higher than 400Pa, control system transferred the 1# compressor to power frequency operation by frequency conversion automatically, the operation of time-delay 0.6s soft start 2# compressor variable frequency.When big jar of tolerance decline, when tank deck pressure was lower than 150Pa, PLC accepted the following limited signal from the PID adjusting apparatus, stopped the 1# compressor of power frequency operation automatically, kept the 2# compressor of converting operation.If tolerance raises again, then transfer the 2# compressor to power frequency operation, soft start 1# compressor variable frequency operation, the two compressors soft start that circulates guarantees that all the time big pressure tank equals setting value.When big jar tolerance falls sharply, when pressure was lower than 100Pa, PLC accepted the following limited signal from the PID adjusting apparatus, and the compressor that stops all working guaranteeing big jar safety.Be provided with the complete protection program in the program design, meet an urgent need and monitor the measure of compressor, guarantee the normal operation of equipment.Also considered frequency converter in the program design just in case break down, system changes emergency rating automatically over to, according to " double site type " control mode, guarantees that big pressure tank is controlled between 150Pa～450Pa to move.

Variable-frequence governor part 5 these parts are main topworks of the present utility model.It regulates the rotating speed of compressor according to 4～20mA signal of adjusting apparatus output, and the signal that simultaneously its fault-signal and frequency is reached 50Hz is given PLC programmable logic controller (PLC) 4, is convenient to PLC and carries out logic control.

Compressor cycle start and stop electric circuit 6 it according to the output signal of PLC programmable logic controller (PLC) 4, control the break-make of each A.C. contactor, reach the purpose of control.

Claims (4)

1, a kind of automatic control natural gas compressor carries out the multifunctional variable-frequency switch board that oil tank gas reclaims, by variable-frequence governor (5), PID adjusting apparatus (3), PLC programmable logic controller (PLC) (4), electric control circuit (6), safety barrier (2), differential pressure transmitter (1) constitutes, it is characterized in that, differential pressure transmitter (1) output analog electrical signal corresponding with it, input to PID adjusting apparatus (3), after the PID computing, output signal to the rotating speed of variable-frequence governor (5) control compressor, when tolerance changes, by PLC logic controller (4) carry out Automatic Cycle start and stop and switching controls, comprise also in its switch board that flammable gas alarm (8) causes that to prevent that natural gas line leaks in the compressor plant accident takes place.

2, oil tank gas according to claim 1 reclaims the multifunctional variable-frequency switch board, it is characterized in that adopting the PLC programmable logic controller (PLC).

3, oil tank gas according to claim 1 reclaims the multifunctional variable-frequency switch board, it is characterized in that adopting the PID adjusting apparatus.

4, oil tank gas according to claim 1 reclaims the multifunctional variable-frequency switch board, it is characterized in that adopting variable-frequence governor.

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