WG valves for a high-pressure CO₂ compressor: 8,000+ hours without failure

A Shandong chemical plant had short valve run times and high compressor power consumption on its 6MD32(3)-195/220 CO₂ compressor. RONDER redesigned the valves for the machine’s high-pressure duty. For the fifth stage, the design used WG valves with 30Cr13 valve plates and included valve dynamics calculations, engineering drawings and a drawing review. After the redesign, the valves operated continuously for more than 8,000 hours without failure.

This case looks at how flow capacity and valve plate impact were balanced in the fifth-stage design.

The redesign brief

The plant wanted to improve the existing valves’ operating performance. The design focused on increasing flow capacity and reducing valve plate impact force, with the aim of extending the operating interval and reducing valve losses.

Valve selection in a multistage CO₂ compressor depends on the stage; this case covers the fifth stage.

Flow and valve motion checks

Flow capacity and valve motion drove the design:

Flow area and passages. Effective flow area depends on passage geometry, lift and the flow coefficient. A flow review should identify restrictions along the gas path and consider how passage shape affects resistance.

Opening, closing and impact. Compressor valves open and close in response to pressure difference. Dynamic analysis can be used to assess timing, flutter and impact velocity. Late closing can reduce delivery and increase impact velocity.

Lift and spring selection. More lift can increase the available flow area at the valve gap, but it can also raise plate impact velocity. Lift, spring characteristics and moving mass have to be selected for the actual duty.

Diagram showing flow capacity, valve plate motion and parameter checks for high-pressure CO₂ compressor valves

Figure 1. Flow and valve motion checks.

WG valve selection and redesign

Valve and plate selection for the fifth stage

For the CO₂ service and high-pressure duty, RONDER selected a WG valve for its greater flow capacity and lower valve plate impact force. The fifth-stage design used a 30Cr13 valve plate.

Valve dynamics calculations

RONDER then calculated valve dynamics against the compressor’s operating conditions. The calculations assessed valve plate motion over the working cycle and informed the structural parameters.

Engineering drawings and review

After the dynamics calculations, RONDER prepared and checked engineering drawings to carry the selected valve and parameters into the valve design.

For a retrofit, the drawing review also covers installation interfaces, assembly and sealing fit, so please send the dimensions and drawings you can share.

Diagram of the fifth-stage WG valve redesign, from valve and material selection through dynamic analysis and drawing review to the operating result

Figure 2. The WG valve redesign process and operating result.

Operating result

The redesigned valves operated continuously for more than 8,000 hours without failure.

For other operating duties, see RONDER’s CO₂ compressor WD valve redesign case and low-pressure chloromethane compressor WP valve case.

Discuss a valve redesign with RONDER

To assess a high-pressure CO₂ compressor valve redesign, email the compressor model, operating conditions and main problem to sales@ronder-valve.com. If available, include:

the compressor model, stage, and whether the valve is on the suction or discharge side;
gas composition, stage suction and discharge pressures and temperatures, running speed, and load variation;
the current valve type, run time, reason for replacement, and shareable photos of failed parts;
shareable installation dimensions or valve drawings, and whether the enquiry concerns an OEM design or an existing machine.

State whether each pressure is gauge or absolute. If you don’t have the full data set yet, the model, stage and a short description of the problem are enough to start.