Multistage compressor section-by-section pressure control device based on PLC (programmable logic controller)

Abstract

The invention relates to a multistage compressor section-by-section pressure control device based on a PLC (programmable logic controller). The multistage compressor section-by-section pressure control device mainly comprises a multistage compressor system and a PLC control system, wherein the multistage compressor system comprises liquid distribution tanks V-1 and V-2, compressors C-1 and C-2 and heat exchangers E-1 and E-2, a valve PV101, a valve PV102, a valve PV103 and a valve PV104 are arranged in the system, and pressure transmitters PT101, PT102 and PT103 are respectively arranged on the liquid distribution tanks V-1, V-2 and V-3. The PLC system comprises a CPU (central processing unit) module, an A / D (analog to digital) module and a D / A (digital to analog) module, the pressure transmitters respectively output analog signals to the A / D module, and the valves are respectively controlled by the D / A module via outputting analog signals. The multistage compressor section-by-section pressure control device has the advantages that the section-by-section pressure control on a multistage compressor is realized, the system pressure stability is ensured, and the accuracy, the timeliness and the safety of the system pressure control are improved.

Description

technical field [0001] The invention relates to a pressure control device, in particular to a stage-by-stage pressure control device of a multistage compressor. Background technique [0002] Hydrocracking is one of the important means of lightening heavy oil. During the hydrogenation reaction, hydrocarbons react with high-pressure hydrogen to remove impurities or produce the desired light products. The pressure of the reaction system is maintained by hydrogen. The pressure of the hydrocracking system is 16-19Mpa. Since the hydrogen pressure from the hydrogen production unit or other hydrogen production units is only 1-2Mpa, it needs to be boosted by multi-stage compressors to meet the pressure requirements of the hydrocracking system. Due to factors such as hydrogen consumption and leakage in the reaction, if hydrogen is not replenished, the pressure will inevitably drop or even fail to complete the hydrogenation reaction. Therefore, it is necessary to provide a pressure co...

AI Technical Summary

Problems solved by technology

For frequency conversion and pressure regulation, its advantage is to save energy, but the cost is high, and it is only applicable to the adjustment of single-stage compressor pressure; for the adjustment of multi-stage compressor terminal outlet directly returning to the first section of inlet, its advantages are simple control and low cost, and its disadvantages are The pressure drop before and after the valve is large, the working conditions are harsh, and it is easy to leak

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