Biogas Purification

Biogas is a renewable energy source and mostly produced from anaerobic digestion (AD). Biogas composition varies with the biomass digested and contains mainly methane (CH4) and carbon dioxide (CO2), as well as traces of hydrogen sulfide (H2S), ammonia ( NH3), hydrogen (H2), nitrogen (N2), carbon monoxide (CO), oxygen (O2). Membrane technology as purification process is a relatively recent but very promising technology. Also, hybrid processes where membranes are combined with other processes are believed to have lower investment and operation costs compared with other processes.


SPECIFICATION

Biogenic Methane IndexOver 97% or recovered in bio natural gas quality
Methane RecoveryOver 96%
Mode to utilize BiomethaneCNG or Gas Network
Unit Energy Consumption0.15-0.25 Kwh/Nm³ Methane
Operating PressureMedium or Low Pressure, 5-10 or 10-20 Bar (According to the product configuration)
Environmental BenefitsMinimum Greenhouse Gas Emissions


SYSTEM COMPOSITION


TECHNOLOGY INTRODUCTION

MEMBRANE TECHNOLOGY

For the Membrane we choose EVONIK as our partner and membrane supplier. Their membrane upgrading process with SEPURAN® Green delivers a constant high biomethane grade with more than 99% purity. In other words, almost all the methane is recovered in bio natural gas quality.
Evonik has developed a biogas upgrading process that makes best use of the membranes' separation properties: Through skillful connection of SEPURAN® Green membranes it is possible to obtain methane with a purity level of up to 99% from the crude gas. Just one compressor is needed.


POLYMIDE MEMBRANE

SEPURAN® Green membranes have the highest CO2/CH4 selectivity and are therefore a superior technology for upgrading biogas. This selectivity of the membranes enables the production of high purity biomethane with superior methane recovery. This distinguishes the Evonik membranes from other membranes that are available.


BENEFITS OF SEPURAN® GREEN MEMBRANE TECHNOLOGY

  • Reduced operating costs

  • Low Investment

  • Easy to operate

  • Low space requirement and short installation times

  • Flexible and modular Installation

  • No chemicals required

  • No additional drying stage


TYPICAL CONFIGURATIONS

Three Stage Membrane Process — Medium Pressure

Biogenic Methane Index: Over 97% or recovered in bio natural gas qualityMethane Recovery: Over 99%

Mode to utilize Biomethane: CNG or Gas Network

Unit Energy Consumption: 0.25-0.25 Kwh/Nm³ Methane

Operating Pressure: Medium Pressure, 10-20 Bar

Environmental Benefits: Minimum Greenhouse Gas Emissions


Two Stage Membrane Process — Medium Pressure

Biogenic Methane Index: Over 97% or recovered in bio natural gas qualityMethane Recovery: Over 97%

Mode to utilize Biomethane: CNG

Unit Energy Consumption: 0.25-0.25 Kwh/Nm³ Methane

Operating Pressure: Medium Pressure, 10-20 Bar

Environmental Benefits: Lower Greenhouse Gas Emissions




Two Stage Membrane Process — Low Pressure

Biogenic Methane Index: Over 97% or recovered in bio natural gas qualit

Methane Recovery: Over 96%

Mode to utilize Biomethane: Gas Network

Unit Energy Consumption: 0.15-0.20 Kwh/Nm³ Methane

Operating Pressure: Low Pressure, 5-10 Bar

Environmental Benefits: Lower Greenhouse Gas Emissions