Accurately Measuring Biogas Concentrations to Optimize Biofuel Production

Shutterstock | Lena Wurm

Increasing awareness of the impact fossil fuels have on the environment, and heavier taxes on carbon emissions has resulted in a global effort to search for renewable sources of energy – alternative energy sources capable of increasing energy efficiency and security.

Biogas, one of the most established renewable energy sources, is a renewable source that has gained major attention in recent years. Biogas is capable of producing heat, electricity, steam and can also be used as vehicle fuel, making it one of the most versatile renewable energy sources available.1

Biogas: The Future of Renewable Energy

Many European countries have presented policies for promoting renewable energy, and this indeed has resulted in an increase in biogas production over the past decade. For example, the number of biogas plants in Europe increased from 16,834 to 17,376 in 2015 – an increase of 3%.2

This resulted in an increase in biogas output, with the amount of electricity generated from biogas estimated at 60.6 TWh; which corresponds to the annual consumption of 13.9 million European households.2

Biogas is developed using bacteria. Organic feedstock, such as manure, food waste and sewage, is broken down by bacteria using an anaerobic (oxygen free) process. This biogas is then processed and used as a source of energy. The key advantages associated with this energy and other renewable sources include decreasing greenhouse emissions and the environmental impact when compared to the use of fossil fuels.

Biogas can be used, in a similar way to fossil fuels, to power cars. Shutterstock | noppawan09

The Challenge of Reliably Measuring Biogas Concentration

The ability to perform accurate concentration measurements is crucial in order to efficiently produce and use biogas as a source of renewable energy. This enables Producers to analyze how much biogas is produced in each stage of production.

However, accurately measuring biogas is considered to be challenging because of the differences in the concentrations of different gases in biogas. The composition of biogas differs based on the source. Biogas normally comprises of 25%-50% carbon dioxide (CO2) and 50%-75% methane (CH4), while the rest is composed of water vapor (H2O) and traces of nitrogen (N2), oxygen (O2) and hydrogen sulfide (H2S).3

These wide ranges show how composition can vary over time with changing conditions, and these compositional changes make biogas extremely difficult to measure confidently.

Additionally, low gas pressures can make most differential pressure devices unsuitable, and biogas is frequently dirty, with high particulate and moisture content. This could lead to the clogging up of measurement devices and make way for errors in gas concentration measurements.

Inaccurate measurement is obviously considered to be problematic. Gas composition is directly related to the competence of fuel cells and turbines for producing electricity. Biogas producers are able to tweak the composition of the final product by measuring the gas composition during production, thus ensuring that the gas generated is useful for clean and efficient energy generation.

Biogas can be converted into electrical energy at dedicated plants. Shutterstock | Moreno Soppelsa

The Ideal Device for Biogas Concentration Measurement

Accurately measuring biogas composition with the correct device is considered to be an obvious solution to these challenges. A gas measurement instrument of integrity is needed as it will be capable of simultaneously measuring the concentrations of carbon monoxide, methane and carbon dioxide present to a high degree to accuracy.

This is important as before an increase in the number of biogas plants in Europe can be established, enhancements in the process efficiency and the development of new technologies for biogas production are essential.

To do this, it is essential to develop the best gas sensing technology that will help in managing and measuring the compositional changes in biogas.

It is necessary for the ideal measurement device to have real-time atmospheric pressure and temperature correction. It should also be capable of allowing integration with a variety of gas detection systems for a highly accurate and reliable measurement of CO2, and CH4 concentrations. The flexibility to work with additional gas detection technologies is also vital, as well as a wide operating voltage range.

Finding an accurate sensor with these features will help in measuring exact biogas concentrations. This in turn enables facilities to enhance their revenue streams and production efficiencies due to increased energy and biogas production.

The Gascard NG for Biogas Concentration Measurement

There is a growing demand for accurate gas sensing technology to measure the concentration of varied gases existing in biogas. This is because finding the perfect device to do this is vital for optimizing the results of biogas production. The Gascard NG infrared gas sensor from Edinburgh Sensors has been designed for effortless integration with a wide variety of gas detection systems that need high quality, reliable and accurate measurement of CO2 and CH4 concentrations.

The Gascard NG from Edinburgh Sensors

It includes atmospheric pressure correction through on-board sensors and real-time temperature, and has the flexibility to integrate additional technologies such as flow sensors. It comprises of onboard true RS232 communications along with the option of TCP/IP communications protocols.

Download the Brochure for More Information

The features of the Gascard NG infrared gas sensor include:

  • Extensive temperature compensation
  • On-board barometric pressure correction in the range 800 mbar to 1150 mbar
  • Minimum operating voltage 7 V and wide operating voltage range (7 V to 30 V)
  • True RS232 communications for data logging and control. Optional on-board LAN support.

References

[1] European Biogas Association, [http://european-biogas.eu/wp-content/uploads/files/2013/10/EBA-brochure-2011.pdf]

[2] BioEnergy Insight Magazine, “Biogas Sector is Growing Steadily in Europe, EBA Says in New Report”, 2017, http://www.bioenergy-news.com/display_news/11600/biogas_sector_is_growing_steadily_in_europe_eba_says_in_new_report/

[3] EBA’s BIOMETHANE Fact Sheet, European Biogas Association, http://european-biogas.eu/wp-content/uploads/files/2013/10/eba_biomethane_factsheet.pdf

This information has been sourced, reviewed and adapted from materials provided by Edinburgh Sensors.

For more information on this source, please visit Edinburgh Sensors.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit