Single-shaft plusing multiple-shaft type carbon dioxide gas centrifugal compressor unit

Abstract

A single-shaft plusing multiple-shaft type carbon dioxide gas centrifugal compressor unit comprises a double extended shafts type driving device. A diaphragm coupling which is used for a left extended shaft of the double extended shafts type driving device is directly connected with a single-shaft type low pressure cylinder. The diaphragm coupling which is used for a right extended shaft of the double extended shafts type driving device is connected with a multiple-shaft type high pressure cylinder. Carbon dioxide gas enters into a first stage impeller of the single-shaft type low pressure cylinder, after four stage compression, the carbon dioxide gas flows out through a back outlet pipeline of a fourth stage of the low pressure cylinder and then enters into a first stage impeller of the multiple-shaft type high pressure cylinder. After another four stage compression, the carbon dioxide gas is discharged from a fourth stage impeller of the multiple-shaft type high pressure cylinder 3 and enters into subsequent process system. The single-shaft plusing multiple-shaft type carbon dioxide gas centrifugal compressor unit can save energy by over 10 % compared with the existing single-shaft plusing multiple-shaft type device and is high in security and stability compared with the multiple-shaft type carbon dioxide gas compressor in foreign.

Description

technical field [0001] The invention relates to a centrifugal compressor unit for pressurizing carbon dioxide in a urea plant, and also relates to the EOR technology (oil field injection CO 2 A single-shaft + multi-shaft carbon dioxide centrifugal compressor unit required in the fields of enhanced crude oil recovery), CCS technology (carbon capture and storage), and pulverized coal spraying in coal gasifiers in coal chemical industry. Background technique [0002] 1. At present, most of the centrifugal carbon dioxide compressor units of urea plants at home and abroad adopt the model of "steam turbine + single-shaft low-pressure cylinder + gearbox + single-shaft high-pressure cylinder". This model has the following technical defects: [0003] The first defect is that the high-pressure cylinder with small flow rate and high-pressure ratio adopts a single-axis type, and the efficiency is very low. [0004] Example: A well-known turbine machinery manufacturing company in the U...

AI Technical Summary

Problems solved by technology

[0003] Defect 1, the high-pressure cylinder with small flow rate and high-pressure ratio adopts a single-axis type, and the efficiency is very low

[0005] Defect 2, the low-pressure cylinder and the high-pressure cylinder are both radial air intake

[0007] Defect three, the steam turbine is at the end, and the low-pressure cylinder shaft needs to transmit the total power of the unit

[0009] Defect 4: It is not suitable for the process optimization requirements of the extraction of multiple pressure levels in the two cylinders and the separate adjustment of each extraction volume

[0011] Defect 5: The surge flow rate in the high-pressure section is close to the flow rate in normal working conditions. When the urea plant is running at reduced load, the four-circuit and three-anti-surge valves are open for a long time, wasting energy

[0019] Defect 1, the pitch speed of the gear is very high, which affects the service life of the high-speed and heavy-loaded pinion and large gear

[0020] Defect 2, the complexity of rotor dynamics brought about by seven-axis or six-axis coupling increases the risk of compressor operation

[0021] Defect three, the power transmitted by the steam turbine through the high-speed pinion shaft is the total power of the unit, and the life of the high-speed heavy-duty pinion is shorter

[0022] Why 10-Stage or 8-Stage Multi-Axis CO 2 In the past ten years since the compressor was launched, there are only a dozen sets of performance in the world (only one of the 10th grade), because the manufacturer blindly expands the multi-shaft model to the entire compressor with a large total pressure ratio, which reduces its operational reliability , not acceptable to users

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