Whether you’re capturing biogas, moving compressed natural gas through a grid, or equipping a fuel station for natural gas vehicles, determining the CNG (compressed natural gas) or RNG (renewable natural gas) that works best for your application can be tricky. Here are six key factors to consider when making this selection:
Efficiency. Did you know that a purpose-designed gas compressor with a pressurized crank case all but eliminates gas leakage by redirecting excess methane back into the compression process? Gas leakage losses can be a huge expense, so selecting a CNG/RNG compressor that accounts for this is a significant consideration. Other benefits from decreased methane leaks include being better for the environment, as well as more gas being available for your processing plant, your pipeline or your mobility stations.
System Design. Keep in mind that a gas compressor must be properly sized to meet the specific requirements of a project. Since gas operations either run 24/7 or must be available 24/7, a fundamental question to answer is what is the maximum flow required? A system that includes at least one VSD gas compressor (see above) can ensure that flow matches demand. Another option to take into account is to think about specifying two or more smaller compressors, rather than one large gas compressor, to provide the needed flow. This enables you to run your process at whatever level is needed, allows service to be performed without shutting down your process, and provides built-in redundancy.
Other aspects of system design include considering a direct drive configuration and water-cooled vs. air-cooled compressors.
Monitoring and Controls. Remote monitoring allows you to have real-time access to all readings on your compressor, anytime and anywhere, through alerts sent via SMS and email. Many CNG and RNG plants are remotely located and some run without any people present, which makes remote monitoring a key capability. Your gas compressors should communicate with you and with each other. This is where centralized controls enter the picture, as these automatically determine which compressor leads and which follows. Running hours are managed to ensure equal usage and reduce maintenance costs. Each gas compressor should have its own native controller. Look for a user interface that is straightforward and intuitive to use, with a modern touch screen.
Power. Looking for an electric or gas-driven compressor? Where electricity provides a lower cost of power, it’s the preferred choice to power a gas compressor, but it’s great to consider the options. A gas-driven compressor can be ideal in remote locations where the cost of electricity is prohibitive or access is unavailable. The same gas that is part of your process can power your compressor.
You should also consider your pressure options. Learn more about that by downloading the full whitepaper.
Build Your System. When designing your system, you should make sure the design is adaptable; i.e. build a modular gas compression system that enables you to change or expand an installation more easily. The flexibility of a modular installation lets you accommodate changes in your process as technology, markets, regulations or business goals change.
Who’s Your Supplier? When searching for the ideal supplier for your CNG/RNG system, you should consider selecting a complete solution supplier for gas compression systems that can assist you in every part of your process – from dispenser to digester. As you evaluate suppliers for your gas compressor system, consider these questions:
Are they a local partner with experience in the field?
Have they worked with your current contractors?
Are they a packager that pieces together the products of other companies, or do they manufacture systems engineered for the specific needs of CNG and RNG applications?
Do they have full-service capabilities?
Learn more about Atlas Copco’s full portfolio of CNG/RNG compressor options by visiting us at www.atlascopco.com/cng!