Carbon Dioxide Compressor

Carbon dioxide (CO₂) is widely used in industrial gases, but its unique properties require special attention. It is colorless and odorless. Due to its relatively high critical temperature (31.03 °C) and its tendency to react with water to form carbonic acid, corrosion and liquefaction must be key considerations when selecting a compressor. Its density is greater than that of air (relative density approximately 1.53), causing it to accumulate in low-lying areas after leakage and posing an asphyxiation risk, which demands high sealing performance from the equipment. CO₂ is extensively utilized in fields such as food and beverages, welding shielding, oil recovery, chemical synthesis, and the emerging CCUS sector, with common cylinder filling pressures of 5–6 MPa. Therefore, the compression process must simultaneously address two major technical challenges: corrosion caused by moisture content and liquefaction resulting from improper cooling.

DIAPHRAGM COMPRESSOR

PISTON COMPRESSOR

Advantages of Carbon Dioxide Diaphragm Compressor:

01

Absolutely Oil-Free and 100% Purity Retention:

The core of a diaphragm compressor lies in its use of a metal diaphragm to completely physically isolate the compressed gas from the hydraulic oil system. The cylinder requires no lubrication. This means that during the entire compression process, carbon dioxide gas does not come into contact with any grease or oil mist, fundamentally eliminating oil contamination. For food-grade CO₂, electronic-grade CO₂, or CO₂ used in high-end chemical synthesis, this characteristic ensures extremely high cleanliness and chemical purity of the product gas, fully meeting the most stringent application standards.
02

Superior Static Sealing and Intrinsic Safety:

The carbon dioxide gas is completely sealed within the "diaphragm cavity" formed by the diaphragm and cylinder head. This is a static sealing structure that theoretically achieves zero leakage. This not only effectively prevents the loss of valuable or hazardous gases, but also completely eliminates the asphyxiation safety risk caused by CO₂ accumulation in low-lying areas due to leakage. Simultaneously, this structure prevents potentially corrosive moist CO₂ from eroding the transmission components, enhancing the operational reliability of the equipment under harsh conditions.

Key Design Points for Carbon Dioxide Diaphragm Compressor:

01

Strict Material Selection for Corrosion Protection:

Since carbon dioxide forms carbonic acid when co-existing with moisture, which is corrosive to ordinary carbon steel, all flow-wetted components in contact with CO₂—including the cylinder head, diaphragm, gas valves, and piping—must be manufactured from corrosion-resistant materials. Austenitic stainless steels (such as 304, 316L) are typically selected, and strict degreasing, cleaning, and passivation treatments are performed after manufacturing to ensure lasting corrosion resistance and gas purity.
02

Precise Temperature and Pressure Control and Anti-Liquefaction Design:

The critical temperature of carbon dioxide is 31.03 °C. During compression, if cooling is insufficient and the gas temperature falls below this critical value while the pressure is high enough, a phase change to liquid is highly likely. Liquid CO₂ inside the compressor can cause a fatal "liquid hammer" phenomenon, damaging the diaphragm and cylinder head. The design must involve carefully calculating and controlling the compression ratio at each stage, and configuring high-efficiency interstage coolers (water-cooled or air-cooled) to ensure that the discharge temperature at each stage is effectively lowered. This strictly confines the operating points of the entire compression path to the gaseous region of CO₂, avoiding the risk of liquefaction.
03

Enhanced Safety Monitoring and Protection System:

Given the large coefficient of expansion of CO₂ under high-pressure storage (the pressure of a full cylinder can surge by 314 – 834 kPa for every 1 °C rise in temperature), the system must integrate multiple protections. Key design elements include: setting up accurate and reliable safety valves at each stage to prevent overpressure; equipping a diaphragm rupture detection and alarm device that can immediately alarm and shut down the compressor upon diaphragm failure to prevent gas-oil mixing; and installing gas concentration monitors in areas where CO₂ may accumulate, linked to the ventilation system. The control system (PLC) should integrate real-time monitoring and interlock shutdown functions for parameters such as pressure, temperature, and diaphragm status.

Certificate

MODEL SELECTION

Model G70Z/G95Z/G110Z/G130Z	Piston Stroke 70mm~130mm	Maximum Piston Force 10KN~30KN
Maximum Discharge Pressure 70Mpa	Flow Range 1~500Nm³/h	Motor Power 2.2KW~30KW
Crankshaft Speed 420rpm	Cooling Method Water Cooled/Air Cooled

Model G70V/G95V/G130V	Piston Stroke 70mm~130mm	Maximum Piston Force 10KN~30KN
Maximum Discharge Pressure 50Mpa	Flow Range 1~200Nm³/h	Motor Power 2.2KW~30KW
Crankshaft Speed 420rpm	Cooling Method Water-cooled / Air-cooled

Model G110L/G130L	Piston Stroke 110mm~130mm	Maximum Piston Force 20KN~40KN
Maximum Discharge Pressure 100Mpa	Flow Range 10~1000Nm³/h	Motor Power 7.5KW~90KW
Crankshaft Speed 420rpm	Cooling Method Water-cooled / Air-cooled

Model G110D/G130D/G150D/ G180D/G182D/G210D	Piston Stroke 110mm~210mm	Maximum Piston Force 20KN~160KN
Maximum Discharge Pressure 100Mpa	Flow Range 30~2000Nm³/h	Motor Power 22KW~200KW
Crankshaft Speed 420rpm	Cooling Method Water-cooled / Air-cooled

Diaphragm type compressor

Piston stroke 70mm

Flow(Nm3/h)

Inlet pressure(barg)

Outlet pressure(barg)

No.	Model	Cooling water	Flow	Inlet pressure	Outlet pressure	Dimensions L×W×H	Weight	Motor Power
No.	Model	(L/h)	(Nm³/h)	(MPa)	(MPa)	(≈mm)	(≈kg)	(kW)
1	GZ-52/40-56	500	52	4	5.6	1200×700×1100	450	3
2	GZ-15/10-12	500	15	1	1.2	1200×700×1100	500	3
3	GZ-20/7-30	500	20	0.7	3	1200×760×1100	750	4
4	GV-60/8-60	1000	60	0.8	6	2600×1800×1700	3000	11
5	GV-500/150-200	1500	500	15	20	2600×1800×1700	3000	18.5
6	GV-160/（6-10）-75	2000	160	0.6-1	7.5	2600×1800×1700	3000	22
7	GL-20/10-150	1500	20	1	15	2200×1200×1300	3000	15
8	GL-25/5-150	1500	25	0.5	15	2200×1200×1300	3000	15
9	GL-45/5-150	2000	45	0.5	15	2600×1300×1300	3000	18.5
10	GD-40/150	4000	40	Atmospheric	15	3500×2000×1700	4000	37
11	GD-300/50-200	4000	300	5	20	3600×2300×1800	4000	45
12	GD-900/10-140	16000	900	1	14	4500×4000×2200	16000	200

The equipment size and weight are for reference only, and the final design shall prevail.

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CASE STUDY

Russia
UNITED STATES
Spain
Kazakhstan

Advantages of Carbon Dioxide Reciprocating Compressor:

01

Wide Operating Condition Adaptability and High Operational Economy:

Reciprocating compressors can adapt to a wide flow range from tens to tens of thousands of Nm³/h, and discharge pressure requirements up to over 20 MPa, fully meeting the engineering needs for large-scale CO₂ recovery, boosting, and transportation. Their high volumetric efficiency, excellent specific power indicators, and long service life of main wearing parts (reaching over 6,000 hours) result in low operating and maintenance costs over the entire lifecycle, offering a significant return on investment.
02

Mature and Reliable Technology with Flexible Regulation Capability:

As a proven and mature technology, reciprocating compressors feature a robust structure and high controllability, capable of continuous and stable industrial operation. Facing changes in gas source pressure or downstream demand, they can flexibly regulate capacity through various methods such as suction regulation, bypass recirculation, and variable frequency drive, achieving rapid response to process flow changes and ensuring the stable operation of the entire gas supply system.

Key Design Points for Carbon Dioxide Reciprocating Compressor:

01

Comprehensive Corrosion Protection and Material Upgrade Strategy:

Similar to diaphragm compressors, corrosion protection is a top priority. All components in contact with wet CO₂, including the cylinder, piston, gas valves, piping, and buffer tanks, must be made of stainless steel or lined with anti-corrosion materials. For the piston rod sealing system, corrosion-resistant packing ring materials should be selected, and a nitrogen purge or buffer sealing system can be designed to prevent process gas leakage, isolate external contaminants, and slow down packing degradation caused by the acidic environment.
02

Thermodynamic and Structural Design Centered on Anti-Liquefaction:

A detailed thermodynamic calculation must be performed based on the physical properties of CO₂. The number of compression stages must be reasonably allocated, and the single-stage compression ratio must be strictly controlled to avoid excessively high discharge temperatures or entering the liquefaction zone. Strengthening inter-stage cooling and final-stage cooling is critical. Coolers with a large heat exchange margin must be selected, and an adequate supply of cooling medium (water or air) must be ensured. A high-efficiency gas-liquid separator and drain valve should be installed on the inlet pipeline to strictly remove any liquid droplets that may be carried in the intake gas.
03

Safety Engineering Design for High Pressure and Asphyxiation Risk:

Given the high-pressure characteristics of CO₂, the system must be designed in accordance with pressure vessel codes and equipped with no fewer than two levels of safety relief devices. Due to the asphyxiation risk from CO₂ leakage, the compressor room must be designed with a forced ventilation system to ensure an adequate air exchange rate. Even though CO₂ itself is non-flammable, all electrical equipment and instrumentation installed in hazardous areas where other combustible materials may be present must meet the corresponding explosion-proof certification requirements. The inherent gas pulsation of the reciprocating compressor must be suppressed through carefully designed inlet and outlet buffer tanks and piping layout to protect downstream equipment and instrumentation.

Certificate

MODEL SELECTION

Z Type

V / W Type

M Type

D Type

Piston stroke 80mm, 95mm	Piston force 10KN～25KN
Power 7.5KW-55KW	Number of cylinder banks 1/2
Crankshaft speed 740 rpm, 980 rpm	Number of compression stages 1/2/3/4
Drive mode Electric motor, diesel engine, natural gas engine

Piston stroke 92mm, 95mm, 105mm, 120mm	Piston force 25KN, 45KN, 65KN
Number of compression stages 1/2/3/4	Number of cylinder banks 2/3/4
Crankshaft speed 740 rpm, 980 rpm	Power 15KW-220KW
Drive mode Electric motor, diesel engine, natural gas engine

Piston stroke 92mm~315mm	Piston force 45KN~660KN
Number of compression stages 1/2/3/4	Number of cylinder banks 4
Crankshaft speed 300rpm~980rpm	Power 160KW-3000KW
Drive mode Electric motor, diesel engine, natural gas engine

Piston stroke 92mm~315mm	Piston force 25KN~200KN
Number of compression stages 1/2/3/4	Number of cylinder banks 2
Crankshaft speed 300rpm~980rpm	Power 30KW-1000KW
Drive mode Electric motor, diesel engine, natural gas engine

Vertical type

Oil-free / F: Air-cooled

Actual volume flow (m3/min)

Inlet pressure(barg)

Outlet pressure(barg)

S/N	Model	Flow	Inlet pressure	Outlet pressure	Motor power
S/N	Model	(Nm³/h)	(Mpa)	(MPa)	(kW)
1	ZW-3/2-3	480	0.2	0.3	11
2	ZW-5.5/2-6	900	0.2	0.6	45
3	ZW-2/20	110	atm	2	22
4	VW-3/20	165	0	2	37
5	VW-4/20	220	0	2	45
6	VW-5/20	285	0	2	55
7	D-12.8/0.12-5	1000	0.012	0.5	90
8	DW-8.8/4 -18	2500	0.4	1.8	160
9	DW-32/0.05-3	1800	0.05	0.3	132
10	MW-5/20-50	6000	2	5	550
11	MW-30/2-8	4900	0.2	0.8	280
12	MW-11/4-20	3000	0.4	2	250