Methanol synthesis reactor

Casale is a worldwide leader company in the field of methanol synthesis technologies, licensing its own technologies for grass-roots and revamping project.
Casale’s core business is the design of synthesis reactor, which takes advantage of Casale technologies to achieve benefits in terms of energy-efficiency and high capacity that are not achievable with other traditional technologies.

Casale began designing new methanol converters and plants in 1980s and, during last 40 years, it became one of the world leading company in methanol field.

Casale has developed skills to design suitable solutions for all common technical cases.

Casale capability is not only limited to design new methanol converters but also to revamp existing reactors designed by other licensors.

The reactor portfolio of Casale allows to create custom and dedicated solution for all specific Client needs.

ARC (Advanced Reactor Concept) technology

ARC technology was originally introduced as a revamp option for the ICI quench lozenge converter, widely used in most of the modern low pressure plants, because of its mechanical simplicity and long term reliability.
The main innovation achieved with the ARC design is the improvement of the temperature profile in the catalyst.
The ARC addresses the above goal through simple, yet effective, modifications of the internals only.

4-bed ARC converterThe main features of the ARC design are:

• re-optimization of the bed splitting;
• improved gas mixing;
• low pressure drops;
• possibility of increasing catalyst volume by exploiting pressure vessel bottom head as part of the last bed;
• simple mechanical construction;
• all parts fit through available manholes;
• no modifications or welding to existing pressure vessel are required.

As a consequence, the benefits resulting from the above features are:

• increased plant output up to about 6% over the total life of the charge;
• uniform bed inlet temperatures (i.e. no hot spots);
• longer catalyst life (normal catalyst life is more than 4 years);
• minimum by-products formation;
• best catalyst utilization.

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IMC (Isothermal Methanol Converter) technology

Methanol synthesis is exothermic, limited by equilibrium. It means that, for each conversion value, there is one temperature that maximizes the reaction rate. The ideal temperature profile should be followed in order to maximize specific production.

Casale Isothermal Methanol Converter (IMC) technology fits perfectly the correct temperature profile resulting the “ideal methanol converter”: exchanger plates are used in place of tubes to contain the cooling media in charge to remove the heat generated by methanol reaction that develops itself outsides cooling plates, where catalyst is loaded.

Casale's IMC reactor is the most advanced design present today on the market, and it has been successfully applied with different type of feedstocks, in natural gas based plants as well in coal-based plants, with capacities ranging from 300 MTD to 7000 MTD.

Its flexible design makes it possible to reach very high production rate in single vessel units, up to 10’000 MTD.

The wide IMC technology portfolio includes gas-cooled and steam-raising variants, and for both of them, axial and axial-radial catalyst bed configurations are available.

IMC Main Features

Cooling plates

Casale IMC converter

Casale has expended a great deal of effort in reactor internals design optimization focusing not only on process and mechanical areas but also involving fluid dynamics, materials, and corrosion specialists.

The following are the most significant design features of the IMC:

• there is no more need of tube sheets: this is the key advantage of the plate design versus multi-tube reactors and allows to scale up reactor design to very large capacities minimizing costs impact;
• heat removal inside the catalyst is performed by heat exchange plates that thanks to their specific features offer the possibility to customize the specific heat transfer surface according to the plant requirements. Reactor control is designed to allow stable and efficient operation in all possible operating conditions, either for steam rising reactors and for gas cooled reactors;
• the heat exchange elements are specially designed for this particular service and the critical environment in which they have to operate (catalyst loading and unloading, thermal expansion, mechanical stress, corrosion stress);
• modular design of the internals allows easy installation and, whenever required, replacement without touching the pressure vessel;
• easy access is provided to the catalyst bed and to all critical points;
• the bed is filled with one continuous layer of catalyst;
• catalyst loading and unloading procedures are familiar, easy to be performed and fast;
• all of the gas flowing into the converter flows through the entirety of the catalyst volume.

IMC Main Benefits

• User friendly operation and control;
• high carbon efficiency per pass;
• minimum energy consumption;
• complete flexibility in all scenarios (reduced load, end-of-run operation, unexpected changes in the operating conditions);
• flexible to use any first-class commercially available catalyst, including Chinese catalysts;
• minimum necessary catalyst volume.

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IMC steam-raising reactors

Axial-radial steam-raising

Axial steam-raising

The IMC steam-raising variant is a quasi-isothermal converter composed by only one isothermal bed, traversed by the process gas in an axial (downward direction) or axial-radial path. All the reaction gas enters the reactor through the top inlet connection while the reacted gas exits the converter through the bottom nozzle at a temperature linked to catalyst age, converter layout and generated steam pressure. The catalyst temperature is kept under control by mean of heat exchanged by cooling plates in which BFW (Boiler Feed Water) flows in counter-current or cross-flow to the gas flow, BFW partly vaporizes as it flows upwards. The converter is provided with circulating pumps to drive the BFW through the plates and with a steam drum to separate the steam from liquid water.

Installation works of axial steam-raising Installation works of axial steam-raising

Key Casale technology for Green Methanol

IMC Methanol synthesis converter is very important for a stable operation either in standard units but also in green methanol applications despite the fluctuations of the feedstocks in terms of flow rate (H₂-CO₂ route) and composition (biomass gasification).

Full Opening IMC

In view of reducing the installation time of IMC internals as well as to simplify any possible repair or replacement, Casale has come up with a design based on a pressure vessel with full bore top opening. This feature permits to pre-assemble all the IMC internals as one single piece at manufacturer workshop.

The one-piece construction allows the following advantages:

• a general simplification of the internals layout, with consequent cost reduction and overall dimension optimization;
• a reduction of the installation time, since, thanks to the full bore top opening of the pressure vessel, the whole will be simply lifted inside as one single piece;
• easier and simpler maintenance to the IMC internals, if required.

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IMC gas-cooled reactors

Axial-radial gas-cooled

Installation works of a large (6 meters) axial-radial gas-cooled

The IMC gas-cooled variant is a quasi-isothermal converter composed by only one catalyst bed traversed by the process gas in an axial or axial-radial path. The single bed can be split in two main regions: an adiabatic zone and an isothermal zone. The first adiabatic volume is not cooled by heat exchange elements and it operates to ensure that the reaction operates close to the maximum reaction rate curve. The second volume is cooled by heat exchanger plates vertically immersed inside the catalyst mass: it is the isothermal portion of the catalyst bed. The cooling medium, circulating through the plate heat exchanger elements, is the incoming reactor feed gas. The plates are designed in order to assure the co-current flow arrangement between the coolant inside the plates and the reacting gas outside the plates either for axial and axial-radial layout.

Thanks to its modular design, which allows internals inside the pressure vessel, Gas Cooled IMC is the unique optimal solution for adiabatic reactors revamping.

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