V CARBON TRANSITION TECHNOLOGIES

Chemical compounds with the elements C, H & O are an essential basis for the organic chemical industry. In natural resources, C, H & O compounds exist in complex forms. For chemical production, they have to be converted into suitable molecules. In general, this takes place in thermo-chemical conversion processes at high temperatures, and often under high pressures.

Thermo-Chemical Conversion via Pyrolysis

Pyrolysis refers to thermal decomposition at high temperatures in the absence of air.
Pyrolysis processes take place at temperatures between 150 – 1100°C. Through pyrolysis, we can produce for example coke from hard coal for iron and steel production in blast furnaces, or charcoal for BBQs.

Grafik Thermisch-chemische Umwandlung durch Pyrolyse

Pyrolysis oil is a complex mixture of C, H & O compounds with diverse utilization  possibilities.Solid pyrolysis coke consists mainly of C and is used e.g. for iron production.Pyrolysis gas is a mixture of carbon monoxide (CO), carbon dioxide (CO₂), hydrogen (H₂) and methane (CH₄).
It can either be used for electricity and heat generation, or for chemical production.

Thermo-Chemical Conversion via Gasification

Gasification refers to the thermo-chemical conversion to gases – mainly carbon monoxide (CO) and hydrogen (H₂) – at high temperatures.
Gasification takes place at temperatures above 800 °C. Oxygen (O₂) is required to achieve such high temperatures. Often, additional steam (H₂O) is needed as well.

Grafik Thermisch-chemische Umwandlung durch Gasifizierung

Synthesis gas – also known as syngas – consists mainly of carbon monoxide (CO) and hydrogen (H₂). From syngas, we can produce diverse basic chemicals such as methanol, ammonia and paraffins.
Subsequently, downstream products are for example plastics, fertilizers and also high-value, CO₂-reduced or CO₂-neutral synthetic fuels (kerosene, diesel and gasoline).

ICON Wusstest du das ...

Did you know what …

... is the difference between combustion and gasification? We explain this using the example of waste as feedstock.

Grafik - Unterschied_Verbrennung_Gasifizierung.jpg


Chemical products can also be produced from carbon dioxide (CO₂) and hydrogen (H₂) - from adding electricity alone. This is called Power-to-X (PtX). The advantages are that CO₂ and H₂ are almost unlimited and that PtX allows a long-term storage of fluctuating renewable electricity.

Power-to-X (PtX)

... is the production of chemical products (X) from electricity.
Just with electricity, carbon dioxide (CO₂) can be washed out from exhaust gases or the atmosphere and hydrogen (H₂) split off from water (H₂O). As synthesis products from these two gases, many basic chemicals such as methanol and paraffins can be produced. Possible secondary products are plastics or high-quality CO₂-neutral synthetic fuels such as kerosene, diesel and gasoline.¹

Grafik Power-to-X (PtX)

Water Electrolysis

... is the splitting of water into H₂ and O₂ through the use of electricity.
A CO₂-neutral and environmentally friendly water electrolysis is operated with renewable electricity. Through this, we can generate CO₂-neutral “green” hydrogen. It can be used in fuel cells for mobility, for power and heat generation, or as reaction gas in the chemical industry and in the metallurgy. The disadvantage is that water electrolysis requires a lot of electricity.

Grafik Wasserelektrolyse


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References

  1. Verfahrenstechnische Maschinen und Apparate (VDMA) Home Page: VDMA Positionspapier Sektorkopplung – Forderungen zu Power-to-X; published March 12, 2018; https://vtma.vdma.org/viewer/-/v2article/render/24782194 (accessed February 20, 2020); VDMA e.V.