Page 31 - Industrial Plants

Figure 5 – Block Flow Diagram of the Methanol Area

to 2, however hydrogen and carbon monoxide are carbon dioxide converted will produce a greater
partially converted to fully oxidized products (carbon amount of the water produced along with methanol
dioxide and water) leading to a lower ratio. The gap to according to equation no. 2 above. Hence, the
reach the ideal value of 2, is closed in the front-end distillation section, has been already designed to cope
section of Project Air’s methanol plant, by adding with this scenario.
hydrogen rich streams to the syngas from gasification. Other minor streams are also recovered from other
According to the process scheme shown in Figure 5, production plants in Perstorp’s site and in the nearby
the syngas produced in the gasification area first industrial area, valorising them by the conversion to
undergoes a front-end purification process removing methanol instead of being used as fuel for steam
the sulphur contaminants. Other hydrogen and carbon generation. These internal streams from the
surrounding specialty chemicals’ plants include:
“Wood is carrying out the Front-End • a tail gas stream from a pressure swing
Engineering Design (FEED) phase adsorption for hydrogen separation and;
of the project in complete overlap • a syngas purge stream.
with the development of the process
design packages by the licensors of They are both collected and mixed with a stream of
methanol and gasification areas carbon dioxide from a regenerator column in an

existing amine unit. In such way, about 19 thousand
carrying gases are added and the resulting syngas tons per annum of carbon dioxide are converted into
composition is strictly controlled to have the optimal methanol rather than emitted to the atmosphere. For
stoichiometric ratio to the conversion loop, to satisfy optimal stoichiometric ratio control of the resulting
the methanol synthesis chemistry summarized above. mixture of all the streams above, a further stream of
Among such streams, the main one is the green external hydrogen is added.
hydrogen produced by the electrolysis unit. Its
production relies on the availability of renewable
electric power from the grid, and it will vary during the Conclusion
plant life: after the start-up, during the first operational Saving 500,000 tons per annum of carbon dioxide
life of the plant, the renewable electric power will be coming from methanol production, Project Air is
limited at 30 MW, while during the second and future overcoming a number of challenges dictated by
period of operation, an increased availability of revamping constraints and flexibility requirements
renewable electric power is expected and embedded and Wood is achieving the goal leveraging its
in the design basis of Project Air. engineering expertise and technological capabilities.
A future scenario with a greater amount of green Project Air stands as a true and ground-breaking
hydrogen will allow for an increased capability of the sustainable methanol initiative, aimed at carbon
methanol plant to replace part of the syngas with neutrality, and deeply involved in the energy transition
externally supplied carbon dioxide from capture as path forward. The paradigm of the transition towards
primary carbon source. This upcoming operation will a climate neutrality is directly embedded into its
target a conversion of about 820 thousand tons yearly design, represented by the flexible handling of
of captured carbon dioxide considering both the different carbon and hydrogen feedstocks, exploiting
external and internal carbon dioxide streams, resulting the synergies with existing surrounding plants and
in a ground-breaking process concept at the core of their side products.
Project Air. Consequently, the increased amount of

IndustrIal Plants - May 2024
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