The Syngas Story: What is it, and what can we do with it?

September 5, 2023
Dr. Sharon Webb
Blog

The Syngas Story: What is it, and what can we do with it?

Part 1: Syngas and the Hydrogen economy

Carbogenesis technology offers a revolutionary approach to carbon capture and utilization, using carbon dioxide to make syngas. This material is universally recognized as a versatile feedstock for industrial processes that make chemicals and fuels and produce energy.

But what is syngas itself, and how is it integrated into the economy?

Syngas, an abbreviation for “synthetic gas,” is a gaseous mixture composed of hydrogen and carbon monoxide. It was first formed industrially in the late 18th century by heating coal in the absence of air; the gaseous mixture resulting from this process was termed “coal gas” and was used for streetlights, home heating, and cooking. In the early 19th century, scientists identified the presence of hydrogen (H2) and carbon monoxide (CO) in coal gas, setting the stage for the systematic study of this material and research into the industrial applicability of hydrogen/carbon monoxide mixtures. As industrialization progressed throughout that century, demand for coal gas and its byproducts grew. Chemical engineering progressed during that period as well, with more efficient processes being developed for producing the hydrogen/carbon monoxide mixture known as syngas, for purifying it, and for shifting its production processes to yield greater amounts of hydrogen from the amounts of hydrogen and carbon monoxide it originally contained. The 20th century introduced a number of processes for making other chemicals from syngas, including methanol and longer-chain hydrocarbons. These processes solidified the position of syngas as a central ingredient for producing a wide range of fuels, chemicals, and plastics.

The two components of syngas, hydrogen and carbon monoxide, are both economically valuable and find uses in a variety of industrial sectors.  In this section, we focus on how syngas can be used to produce hydrogen and can thus play an essential role in the burgeoning hydrogen economy. In a hydrogen-based economy, hydrogen can be substituted for fossil fuels in various settings, including as a clean energy source, an energy carrier, and a feedstock for crucial chemical reactions. Syngas, a hydrogen repository, holds the potential as a valuable contributor to the hydrogen economy.

Although syngas contains a carbon product (carbon monoxide), it also contains hydrogen. The hydrogen in syngas can be separated from the syngas mixture and used separately, either as an energy source or as a component of other chemicals. Hydrogen is a highly desirable fuel that can be burned for power generation without forming any greenhouse gases. As the following equation shows, hydrogen can be combusted (combined with oxygen) to produce energy, only forming water vapor and energy – no carbon is involved:

O2 + 2H2 ->2H2O + 484 kJ energy

Notably, hydrogen combustion in ambient air will also involve reactions with the nitrogen in the air so that nitrogen oxides (NOx) are formed. As an alternative, hydrogen can be incorporated into fuel cells to produce energy without combustion, thus avoiding the undesirable NOx byproducts. Hydrogen is also used to propel vehicles such as rockets that operate in a nitrogen-free environment.

As an alternative to combustion, hydrogen can be incorporated into fuel cells to generate power. Further, hydrogen can be combined with other chemicals to make more complex materials with multiple applications. For example, hydrogen is vital in the Haber-Bosch process to produce ammonia, a crucial chemical used in fertilizers, plastics, and explosives. In other chemical processes, hydrogen is used as a reducing agent, for example, to extract pure metals from their ores and as a reactant in other chemical processes, including the production of hydrochloric acid, hydrogen peroxide, and saturated organic compounds.

An important chemical reaction involving hydrogen is the formation of methanol (CH3OH), formed by combining hydrogen with carbon monoxide, as shown in the following equation:

CO + 2H2 -> CH3OH

As mentioned above, both carbon monoxide and hydrogen are components of syngas; making methanol is, therefore, a straightforward and economical way to put syngas to work. Methanol, in turn, acts as a chemical intermediate for producing a variety of other chemicals, including formaldehyde, acetic acid, acrylic acid, dimethyl ether, biodiesel, and light olefins.  Methanol production for 2022 was estimated to reach over 111 million metric tons, an increase of 4% as compared to 2021.

Many methods in chemical engineering are available for producing syngas, as will be discussed further in Part 3 of the Syngas Story. Importantly, these methods can be adjusted so that more hydrogen is produced from the initial reactants at the expense of forming more carbon dioxide. As a simple example, a method for syngas production termed dry reforming of methane (DRM) employs methane (CH4) and carbon dioxide as feedstocks for forming syngas, according to the following equation:

CH4 + CO2 →2H2+ 2CO

The carbon monoxide that is formed by this process can then be converted into even more hydrogen using a process called the water-gas shift (WGS) reaction, as shown in the following equation:

CO + H2O ↔ CO2 + H2

Although the WGS reaction produces CO2, an undesirable greenhouse gas, the reaction also produces hydrogen that can be used as a sustainable, non-fossil-fuel-based energy source. And, as noted in the equation above, the CO2 formed during the WGS reaction can provide feedstock for forming more syngas, which in turn yields more hydrogen and carbon monoxide.

While full realization of a hydrogen economy may be an elusive goal that faces many technical and environmental challenges, its ultimate success depends on addressing those challenges in ways that are themselves sustainable. For example, hydrogen is overwhelmingly produced using fossil fuels, and hydrogen production emits hundreds of millions of tons of carbon dioxide per year. Producing hydrogen using reactions that generate carbon dioxide undercut the decarbonization mandate of the hydrogen economy. -- Dr. Sharon Webb

The Carbogenesis technology, by permitting the productive utilization of carbon dioxide, offers an important answer to the CO2 emissions problem that plagues the hydrogen economy. By activating CO2 as a plasma, Carbogenesis can use this pollutant to produce syngas, a familiar and convenient source of hydrogen. Carbogenesis can also use the CO2 produced by the conventional reactions that generate hydrogen – to produce more hydrogen! By becoming integrated into conventional processes that manufacture hydrogen (and produce carbon dioxide), Carbogenesis can thus take us further down the path of decarbonization, helping to usher in a circular economy based on non-carbon-based sources for energy and industrial chemicals.