Ethylene compressors

Ethylene (C₂H₄), known as the "industrial grain" of the petrochemical industry, is the organic basic raw material with the largest global production volume. This gas is colorless with a slightly sweet odor, has an extremely low critical temperature (9.21°C), can be liquefied under pressure at room temperature, and is highly prone to phase change during compression. It is also flammable and explosive, with an explosion limit of 3.1% to 32% in air. By virtue of its reactive double bond, ethylene serves as the core starting point for downstream products such as polyethylene and synthetic rubber, imposing extremely high requirements on the performance and reliability of compression equipment.

DIAPHRAGM COMPRESSOR

PISTON COMPRESSOR

Ethylene Diaphragm Compressor Advantages:

01

Absolutely Oil-Free & Ultra-High Purity Assurance:

The diaphragm isolation technology ensures that the gas is 100% free from contact with lubricating oil during compression, achieving a compression purity of over 99.999%. This is critical for "polymer-grade" ethylene used as a polymerization feedstock, where even trace oil contamination can affect catalyst activity, leading to product quality degradation or even polymerization failure.
02

Static Seal Zero Leakage & Intrinsic Safety:

The entire gas chamber employs a static seal structure, fundamentally eliminating the possibility of gas leakage. For ethylene, which has a wide explosion limit and high hazard level, this feature provides the highest level of safety assurance, effectively preventing the accumulation of flammable gas in the plant area and meeting the most stringent safety production and environmental protection requirements.

Key Design Points for Ethylene Diaphragm Compressors:

01

Precise Anti-Liquefaction & Temperature Control Design:

Given that the critical temperature of ethylene (9.21°C) is close to ambient temperature, it is highly prone to liquefaction during compression and cooling, which can cause "liquid slugging." The design must include accurate thermodynamic calculations to ensure that the discharge temperature and the gas temperature after inter-stage cooling always remain above the dew point at the corresponding partial pressure, with a sufficient safety margin. The cooling system must be efficient and reliable to prevent gas condensation within the chamber or piping.
02

High-Pressure & Material Compatibility Design:

To meet the demands of processes such as ultra-high-pressure polyethylene synthesis, the compressor must adopt a multi-cylinder series arrangement or a specially reinforced structure to achieve discharge pressures exceeding 100 MPa. Materials for wetted parts are typically selected as 316L stainless steel or higher-grade alloys to ensure high-pressure strength while providing excellent chemical inertness, preventing any adverse reactions with ethylene. The use of copper and its alloys is strictly prohibited to avoid catalyzing the formation of hazardous polymers from ethylene.
03

Multi-Layered Safety Monitoring & Protection System:

A three-layer diaphragm structure is standard, equipped with a diaphragm rupture monitoring and alarm device. If the inner diaphragm is damaged, the system can immediately trigger an alarm and safely shut down. The system must integrate interlocks such as high discharge temperature and pressure alarms, as well as oil pressure protection. For process connections, nitrogen purge connections should beto allow for inerting and purging of the system before startup, ensuring safe operation.

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

High Pressure Ethylene Diaphragm Compressor

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)

5.3

Inlet pressure(barg)

12.5

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-18/5.3-12.5	500	18	0.53	1.25	1000×800×1100	800	5.5
2	GZ-30/20-60	500	30	2	6	1100×800×1100	800	7.5
3	GZ-22/7-30	1000	22	0.7	3	1200×800×1100	800	11
4	GV-20/7-150	1000	20	0.7	15	1400×800×1100	900	11
5	GV-118/（34.5-44.5）-55	1000	118	3.45-4.45	5.5	1400×800×1100	1000	11
6	GV-160/（0.35-10.5）-30	2000	160	0.035-1.05	3	2600×1800×1600	3000	18.5
7	GL-55/3	1000	55	Atmospheric	0.3	2200×1800×1600	2800	11
8	GL-130/0.3-0.5	1500	130	0.03	0.05	2300×1800×1600	2800	11
9	GL-40/0.2-25	2000	40	0.02	2.5	2300×1800×1600	2800	18.5
10	GD-180/2.3-61.3	4500	180	0.23	6.13	3800×2300×1800	6000	45
11	GD-1076/（17-24）-125	10000	1076	1.7-2.4	12.5	4200×3200×2200	12000	132
12	GD-945/11.7-126	15000	945	1.17	12.6	4200×3500×2200	12000	160

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

Ethylene Piston Compressor Advantages:

01

Broad Pressure Adaptability & High Compression Efficiency:

Piston compressors can cover a wide range of pressure requirements from medium to high pressure, flexibly adapting to different process pressure levels through multi-stage compression. Their high volumetric efficiency makes them suitable for handling large-scale flow rates, meeting the immense demands of million-ton ethylene plants for feedstock gas boosting and recycle gas compression.
02

Highly Mature Technology & Maintenance Convenience:

As the most classic compressor type in the industrial field, the piston-type ethylene compressor boasts the broadest application cases and deepest technical accumulation, with fully verified operational reliability. Its relatively standardized structure and mature procedures for replacing wearing parts and performing maintenance help reduce the complexity and cost of long-term operation and maintenance.

Key Design Points for Ethylene Piston Compressors:

01

Strict Inter-stage Cooling & Gas-Liquid Separation Design:

Preventing liquefaction is the lifeline of ethylene piston compressor design. Multi-stage compression must be adopted, with efficient inter-stage coolers and high-efficiency gas-liquid separators configured at the outlet of each stage. The core of the design lies in accurately calculating the pressure ratio for each stage, ensuring that the outlet temperature of the cooler is absolutely higher than the dew point of ethylene at that stage's pressure, and thoroughly separating any liquid droplets that may form, strictly preventing liquid ethylene from entering the next stage cylinder and causing catastrophic "liquid slugging."
02

Optimized Structure Selection & Seal Type:

For medium to large flow rates, a horizontal opposed balanced structure is preferred, offering good dynamic balance and low vibration, suitable for long-term continuous operation. Depending on gas purity requirements, an oil-free lubrication design or labyrinth seal type can be selected to minimize lubricating oil contamination of the process gas. The packing system must be designed with a nitrogen buffer seal to prevent gas leakage and purge any leaked ethylene to a safe area.
03

Comprehensive Safety & Operating Condition Adaptability Configuration:

All electrical instruments must comply with the Ex d IIC T2 group explosion-proof rating to suit the explosive environment of ethylene. Filters and separators should be installed upstream of the compressor inlet to ensure clean, dry intake gas. The system must be equipped with a complete set of safety valves, with relieved gas routed to a flare system or recovery unit. Considering that ethylene may carry trace heavy components or operate under special conditions, the materials of key pressure-containing parts should possess good comprehensive mechanical properties. For processes that may involve low temperatures, materials meeting the requirements for low-temperature Charpy impact toughness must be selected.

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

2.1

Actual volume flow (m3/min)

0.15

Inlet pressure(barg)

Outlet pressure(barg)

S/N	Model	Flow	inlet pressure	outlet pressure	motor power
S/N	Model	(Nm³/h)	(MPag)	(MPag)	(kW)
1	ZW-2.1/0.15-15	110	0.015	1.5	22
2	ZW-0.9/6-25	330	0.6	2.5	30
3	ZW-0.63/3-200	120	0.3	20	37
4	VW-7.2/1-22	800	0.1	2.2	132
5	VW-6/20	330	atm	2	75
6	VW-6.8/30	370	atm	3	75
7	DW-9.5/6	600	0.005	0.6	75
8	DW-12.5/29.9-53	21000	2.39	5.3	355
9	DW-8.8/4 -18	2050	0.4	1.8	132
10	MW-154/6	10500	0.05	0.6	1100
11	MW-6/15-21	6000	1.5-2.0	2.1	185
12	M-40/3-7	9000	0.3	0.7	450