Select the Right CMS Grade for Your PSA Nitrogen Generator
Carbon Molecular Sieve Model Selection Guide
Choosing a Carbon Molecular Sieve is not simply a matter of selecting the highest CMS grade or asking which product can produce 99.999% nitrogen.
Kingdotech supplies CMS-220, CMS-240, CMS-260 and CMS-280 for different PSA nitrogen generation requirements. Each grade has a different commercial and performance positioning, but the final model should be selected according to the actual PSA system rather than the model name alone.
Send Kingdotech your nitrogen purity, flow rate, operating pressure and tower information. Our team will help you identify a suitable CMS grade, estimate the required loading quantity and prepare a technical quotation.
Quick CMS Selection Form
Provide the following basic information to receive an initial CMS recommendation:
| Required information | Example |
|---|---|
| Nitrogen purity | 99.9%, 99.99% or 99.999% |
| Nitrogen flow rate | 50 Nm³/h |
| Feed-air pressure | 7 bar |
| Project type | New PSA system or CMS replacement |
| Existing CMS model | CMS-240 or unknown |
| Application | Laser cutting, food packaging or heat treatment |
| Required quantity | 500 kg, 1 ton or pending calculation |
| Destination country | Buyer’s delivery destination |
Quick Carbon Molecular Sieve Selection Overview
Carbon Molecular Sieve selection should begin with the required nitrogen purity, but purity alone is not enough to determine the final CMS model.
PSA nitrogen purity and flow are affected by the complete system. Official PSA generator documentation shows that nitrogen purity is dependent on pressure, temperature and flow, and that the same generator normally produces less nitrogen as the required purity increases.
Main CMS Selection Factors
| Selection factor | Why it matters |
| Nitrogen purity | Determines the required oxygen separation level |
| Nitrogen flow rate | Determines the amount of nitrogen the PSA system must produce |
| Operating pressure | Influences CMS adsorption performance |
| PSA cycle time | Must match the adsorption and regeneration speed |
| Tower dimensions | Determine the effective CMS bed volume |
| Bulk density | Influences the required filling weight |
| Air-to-nitrogen ratio | Influences compressor power and operating cost |
| Feed-air quality | Oil, water and dust can damage CMS performance |
| Existing CMS | Important for replacement compatibility |
| Application industry | Determines purity stability and operating priorities |
A CMS grade that is appropriate for a high-purity, low-flow PSA generator may not be the most economical choice for a lower-purity, high-flow system.
Similarly, using a higher-numbered CMS grade does not automatically guarantee better results if the adsorption tower, valves, compressed-air supply or cycle settings do not support it.
Kingdotech CMS Model Comparison
Kingdotech currently supplies four main CMS grades for PSA nitrogen generation: CMS-220, CMS-240, CMS-260 and CMS-280. Kingdotech positions these grades for different purity, output, efficiency and operating requirements.
CMS Model Selection Matrix
| Kingdotech grade | General positioning | Suitable starting direction | Main buyer priority |
| CMS-220 | Standard CMS grade | General PSA nitrogen generation and cost-sensitive systems | Stable basic performance and procurement cost control |
| CMS-240 | Balanced performance grade | Medium-demand systems requiring a balance of purity, flow and price | Price-performance balance |
| CMS-260 | Higher-efficiency grade | Higher nitrogen output, higher purity or improved operating efficiency | Nitrogen recovery and output stability |
| CMS-280 | High-performance grade | High-purity and demanding continuous PSA nitrogen systems | Purity stability and long-term performance |
This table is intended for initial commercial screening. It is not a fixed guarantee that one CMS grade will achieve the same purity or flow in every PSA generator.
CMS-220
CMS-220 is generally positioned as a standard Carbon Molecular Sieve for general PSA nitrogen generation.
It can be considered when the buyer’s main priorities are:
- Controlled purchasing cost
- General industrial nitrogen production
- Standard PSA system operation
- Stable basic nitrogen output
- Replacement of a comparable standard CMS grade
CMS-220 should not be selected only because it has the lowest initial purchasing cost. Buyers should still confirm whether the CMS can meet the required purity and flow under the actual PSA operating conditions.
CMS-240
CMS-240 is positioned as a balanced-performance grade. It is often considered when buyers need a practical balance between nitrogen purity, nitrogen flow, CMS price and operating cost.
It can be a useful starting point for:
- Medium-demand PSA nitrogen generators
- General industrial continuous nitrogen supply
- Food packaging nitrogen systems
- Standard laser-cutting nitrogen systems
- Buyers upgrading from a basic CMS grade
- OEM projects requiring a balance of cost and performance
CMS-240 may be appropriate when CMS-220 cannot provide the desired performance margin, but the project does not require the higher-performance positioning of CMS-260 or CMS-280.
CMS-260
CMS-260 is positioned for systems requiring higher nitrogen productivity, higher purity or improved adsorption performance.
Kingdotech currently describes CMS-260 as a higher-efficiency direction for buyers who place greater importance on nitrogen recovery, output stability and system efficiency.
CMS-260 may be evaluated for:
- Medium-to-high-purity nitrogen generation
- Higher-output PSA nitrogen generators
- Continuous industrial nitrogen production
- Laser-cutting nitrogen systems
- Metal heat-treatment applications
- Electronics manufacturing
- PSA generator OEM production
- Projects seeking improved air utilization
A higher unit price may be justified when the selected CMS helps the properly designed PSA system produce more nitrogen or reduce compressed-air demand.
CMS-280
CMS-280 is positioned as Kingdotech’s high-performance grade for high-purity and demanding PSA nitrogen generation requirements.
Typical buyers may include:
- High-purity PSA nitrogen generator manufacturers
- Precision laser-cutting facilities
- Electronics production companies
- Heat-treatment equipment operators
- Industrial gas system integrators
- Buyers replacing a high-performance CMS grade
CMS-280 should not automatically be selected for every 99.999% nitrogen project. High-purity production also requires suitable tower design, sufficient bed volume, controlled compressed-air quality, accurate valve switching and proper regeneration.
Need a CMS Model and Accurate Quotation?
Submit your PSA specifications to receive a recommended CMS grade, estimated filling quantity, packaging option and bulk quotation.
CMS Selection by Nitrogen Purity
Required nitrogen purity is the first selection factor because it defines the maximum acceptable residual oxygen content.
However, the same purity target can require different CMS solutions depending on nitrogen flow, operating pressure and PSA system design.
Initial Selection Direction by Nitrogen Purity
| Required nitrogen purity | Initial CMS direction | Main selection priority |
| 95%–99% | CMS-220 or CMS-240 | High nitrogen output and cost control |
| 99%–99.5% | CMS-220, CMS-240 or CMS-260 | Balance of purity, flow and operating cost |
| 99.5%–99.9% | CMS-240 or CMS-260 | Stable oxygen adsorption and batch consistency |
| 99.9%–99.99% | CMS-240 or CMS-260 | Purity stability, output and air consumption |
| 99.99%–99.999% | CMS-260 or CMS-280 | High-purity performance and complete PSA system matching |
These ranges are only initial model directions. Kingdotech’s application pages currently use similar CMS-220/CMS-240, CMS-240/CMS-260 and CMS-260/CMS-280 progression for standard, medium-to-high and high-purity PSA nitrogen requirements.
CMS for 95%–99% Nitrogen
For lower-purity nitrogen systems, the main purchasing goal is usually higher nitrogen output at a controlled operating cost.
The CMS selection should prioritize:
- Stable productivity
- Reasonable compressed-air utilization
- Mechanical strength
- Low dust generation
- Consistent filling density
- Competitive purchasing cost
A high-performance grade may not provide a sufficient economic advantage if the application does not require high purity.
CMS for 99%–99.5% Nitrogen
This purity range is common in general industrial nitrogen systems where buyers need a balance between product purity, nitrogen flow and operating cost.
Selection priorities include:
- Stable oxygen adsorption
- Consistent nitrogen output
- Controlled air consumption
- Suitable cycle performance
- Reliable batch quality
CMS-220, CMS-240 or CMS-260 may be considered depending on the generator design and the required performance margin.
CMS for 99.9% Nitrogen
For 99.9% nitrogen, buyers should pay more attention to CMS consistency and system matching.
The recommended CMS must work with:
- Actual nitrogen flow
- Operating pressure
- Adsorption time
- Regeneration time
- Effective tower volume
- Feed-air dew point
- Continuous operating hours
CMS-240 or CMS-260 is often a practical initial direction, although some systems may use other grades depending on their design.
CMS for 99.99% Nitrogen
At 99.99% nitrogen purity, residual oxygen control becomes more demanding.
The buyer should evaluate:
- Oxygen adsorption performance
- Adsorption and desorption speed
- CMS batch consistency
- Air pretreatment
- Valve leakage
- Tower pressure balance
- CMS loading method
- Nitrogen flow at the required purity
CMS-240 or CMS-260 may be considered as an initial direction, while CMS-280 may be evaluated for more demanding systems.
CMS Selection for New PSA Nitrogen Generators
For new PSA nitrogen generator projects, CMS selection should take place before the tower design and valve cycle are finalized.
| Design information | Purpose |
| Target nitrogen purity | Defines the separation requirement |
| Target nitrogen flow | Defines generator capacity |
| Feed-air pressure | Defines adsorption conditions |
| Product pressure | Defines delivery requirements |
| Tower diameter and height | Defines effective bed volume |
| Planned cycle time | Defines kinetic matching |
| Compressor capacity | Defines available feed air |
| Air-treatment design | Defines CMS protection |
| Application | Defines operating priorities |
| Expected production quantity | Supports batch-supply planning |
Step-by-Step Carbon Molecular Sieve Selection
Selecting the right CMS requires more than confirming nitrogen purity. Use the following six steps to complete an initial selection for a new PSA system or replacement project.
Step 1: Confirm Nitrogen Purity
Determine the actual nitrogen purity required by your production process. Higher purity usually means lower nitrogen output and higher compressed-air consumption, so avoid selecting a purity level higher than necessary.
Step 2: Confirm Nitrogen Flow
Specify the nitrogen flow required at the target purity. Include both normal and peak demand, especially if the system operates continuously or has large flow fluctuations.
Step 3: Check Operating Pressure
Feed-air pressure affects CMS adsorption performance, while product pressure affects the usable nitrogen flow. Unstable or insufficient pressure may reduce purity and output.
Step 4: Review PSA Cycle Time
The CMS must match the adsorption, depressurization and regeneration cycle of the PSA generator. A replacement CMS may require cycle adjustment during commissioning.
Step 5: Confirm Tower Size
Adsorption tower dimensions determine CMS bed volume and approximate loading quantity. Final quantity must also consider internal supports, protective layers and actual CMS bulk density.
Step 6: Identify the Project Type
New PSA systems and replacement projects require different selection methods. Replacement projects should also review the original CMS, current purity, operating history and cause of performance decline.
Submit these six groups of parameters to Kingdotech for a CMS grade recommendation, filling quantity estimate and quotation.
How to Calculate CMS Filling Quantity
The approximate CMS quantity can be estimated from the effective tower volume and the confirmed bulk density of the selected grade.
Basic Calculation
Estimated CMS quantity = Effective filling volume × CMS bulk density
For a cylindrical adsorption tower:
Effective filling volume = π × Internal radius² × Effective filling height
Example Calculation
Assume one adsorption tower has:
- Internal diameter: 0.8 m
- Effective filling height: 2.0 m
- Confirmed CMS bulk density: 650 kg/m³
- Number of towers: 2
Radius:
0.8 ÷ 2 = 0.4 m
Volume of one tower:
3.1416 × 0.4² × 2.0 = approximately 1.005 m³
Estimated CMS quantity for one tower:
1.005 × 650 = approximately 653 kg
Estimated quantity for two towers:
653 × 2 = approximately 1,306 kg
This is only a preliminary mathematical estimate.
The final loading quantity may be affected by:
- Internal gas distributors
- Support screens
- Activated alumina layers
- Top compression devices
- Effective usable height
- Filling and vibration method
- Material settlement
- Actual batch bulk density
- Original equipment requirements
Kingdotech’s current product page publishes general CMS indicators including particle size of 1.7–2.2 mm and bulk density of at least 0.65 g/ml. The selected model and batch datasheet should be confirmed before the final quantity is ordered.
Why Choose Kingdotech for CMS Model Selection?
Replacement Support
Kingdotech can evaluate both new PSA generator projects and existing CMS replacement requirements.
Bulk Supply and Packaging
Kingdotech can support PSA equipment manufacturers, industrial users, distributors and bulk buyers requiring international delivery.
Get the Right CMS Model for Your PSA Nitrogen Generator
Send Kingdotech your nitrogen purity, flow rate, operating pressure, PSA cycle, tower dimensions and existing CMS information. Our team will review the application and recommend a suitable CMS grade, estimated filling quantity, sample option and quotation.
