In modern biomethane production plants, the screw compressor is used as the primary compression stage because of its efficiency, reliability, and ability to treat large flow rates continuously, efficiently, and reliably. Downstream, the reciprocating compressor acts as a booster, bringing the gas to the higher pressures required for feed-in or storage. This combination ensures maximum energy efficiency, low maintenance, and 24/7 operational reliability. 

SAFE S.p.A., a leading player in compression solutions for biomethane, CNG and hydrogen, recently brought to market a new package with screw compressor developed for compressing biogas in the upgrading process to biomethane. The unit is designed to ensure continuous operation, maximize energy efficiency, and simplify plant integration. It is available in a containerized “plug and play” configuration to minimize installation and commissioning times. 

SUITABLE FOR A RANGE OF APPLICATIONS

The new SAFE compressor has been developed to operate under very low suction conditions (100– 500 millibar), maintaining stable performance with variable flow rates up to 2,500 standard cubic meters per hour and discharge pressures up to 16 bar gauge. The new screw-compressor range spans installed power up to 400 kW, making it suitable for integration in both small- and large-scale plants. 

The water-cooling system (with SAFE-supplied air cooler—installable on the top of the container or at ground level alongside it) and the oil-flooded screw configuration, with triple gas filtration, ensure thermal stability, reliability and service quality. The sound level of the compression package in operation is limited to 60 dB(A) at 1 meter. 

INNOVATIVE DESIGN

The heart of the unit is the compressor body on a slide-out removable skid, a solution that enables immediate access and fast replacement during maintenance services. Machine control is oriented toward maximum efficiency: service regulation is based on maintaining suction pressure, with automatic motor speed adjustment, and a recirculation line to handle processes with variable flow rates and pressures—extending the operating envelope. 

Options include a heat recovery system, sub-cooling with chiller and outlet biogas temperature control. These extensions have been developed and made available to increase overall service efficiency and facilitate integration with plant interfaces. 

A READY-TO-USE SOLUTION 

With this new screw compressor, we are providing the biomethane market with a robust, efficient and easy-to-integrate industrial platform, capable of continuous operation and optimizing consumption even in the presence of variable flow rates and very low suction. The goal is to give customers a ready-to-use solution, scalable and configurable on existing plants, that reduces commissioning times and maximizes reliability over the life cycle.

TECHNICAL NOTES

  • Suction pressure: 100–500 millibar; Discharge pressure: up to 16 bar gauge
  • Flow range: up to 2,500 standard cubic meters per hour
  • Installed power range: 75–400 kW; Noise: up to 60 dB(A) at 1 meter 
  • Basic product configuration: “plug and play” container; water cooling with SAFE air cooler; oil-lubricated screw compressor skid with triple filtration
  • Slide-out removable skid for fast and easy maintenance; service control on suction pressure with internal recirculation; options: heat recovery, chiller, outlet temperature control.

Riccardo Bagagli is chief technology officer for SAFE. SAFE designs and manufactures compressors and infrastructure for natural gas, hydrogen, and biomethane, offering complete solutions from the well to distribution and refueling for mobility. It has always promoted the use of clean energy through innovation, experience and responsibility. SAFE is distinguished by its ability to develop tailor-made solutions that provide maximum flexibility, modularity, and adaptability to any application context. For more information, visit www.safegas.it.