The Carbon Challenge - part 2: Carbon Capture & Storage as part of the solution

02 Feb 2022

 

It is clear that global warming must be reversed. Europe, for example, has expressed a great ambition to
become carbon neutral by 2050. Earlier we explained the climate challenge and the role of waste in this challenge. In this second blogpost on the Carbon Challenge you will discover about “Carbon capture & storage” as a solution to combat global warming. We will also highlight the potential role of Waste-to-Energy in this emerging technology.
 

Back to the COchallenge. How much CO2 does a Waste-to-Energy plant emit?

Each ton of incinerated household waste produces approximately 1 ton of CO2. Typically 50% of CO2 comes from the combustion of fossil carbon (plastics) and 50% from the combustion of biogenic carbon (cardboard, textiles, food waste, …). Biogenic carbon is therefore actually CO2 that was once present in the atmosphere and has now converted to natural carbon chains via photosynthesis.
Capturing the fossil CO2 fraction and storing it permanently would make it a CO2 neutral process. Capturing and permanently storing the biogenic carbon would create a CO2 negative process. This way we reduce the concentration of CO2 in the atmosphere. The combination of Waste to Energy with carbon capture storage is one of the few carbon dioxide removal technologies next to Direct Air Capture or Bio-energy combustion combined with carbon capture & storage. Climatologists rely on such large-scale carbon removal technologies to keep global warming below 1.5°C, as shown in the figure below.
 

3.png

4.jpg


How do we as Keppel Seghers tackle this challenge?

We are actively working on 'carbon capture & storage' technology with our innovation team. It is After all, it is an obvious and necessary next step in the Waste-to-Energy evolvement. Historically, people initially only started incinerating the waste without further ado. As we already explained in the 1st blogpost people then started using the heat via a boiler and converted it into energy. The next historical challenge concerned the purification of the emitted gases, for which the application of flue gas scrubbing offered a solution.
This makes integrating carbon capture technology a logical next step for Waste-to-Energy in line with societal challenges.
 

How does such a carbon capture & storage process work?

This process develops in several steps. In the first step, the flue gases are cooled and then brought into contact with a liquid that will selectively retain the CO2. The liquid rich in CO2 is then heated using low-pressure steam what causes the CO2 to be released selectively. Doing this pure CO2 stream is produced. This pure stream is compressed to be transported for storage purposes.

 
Are these innovations something of the near or distant future?

In the Netherlands, waste incineration plants are already equipped with a carbon capture installation. We also see other countries reflecting and working on carbon capture and storage  technology. The waste incineration plant in Oslo is an interesting example. They are aiming to permanently store the captured CO2 about 2.5km meters below the seabed.
 

Are there other ways to store CO2?

In addition to permanent underground storage, technology is also being developed to permanently store the CO2 in minerals or thermally treated residual products that can be converted into construction materials using CO2. Storage in basalt minerals is already taking place in Iceland.

What are other innovations and optimizations you are working on at Keppel Seghers?

Our focus is on the one hand increasing our efficiency as well as on the other hand contributing more to the circular economy. For example our permanent focus on improving combustion: how can we optimize efficiency and thus extract more energy from 1 ton of waste? In addition, there is a focus on how we can better recover metals from the combustion ashes so that they can be reused.

5.png


So work to be done for our fellow engineers?

Definitely!