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Young Researchers

SP7 - Process engineering and economic evaluation

A process simulation was performed integrating the different process steps and further developed along the project to reach the most sustainable design considering different aspects such as economic constraints and achieved performances during the experimental phase of the project.

An economic study was performed and was based on the calculation of fixed capital investment as well as cost of production defined by the process simulation. Two cases were considered:

  1. The first case represented the results obtained during the OCMOL project from the laboratory phase

  2. The second case represented results which could be possibly achieved with additional R&D efforts.

Both cases show that the project could be economic.

The following recommendations were made to improve the competitiveness of OCMOL:

  • The investment has to be as low as possible by economizing expensive separation steps.

  •  The production of liquids via methane coupling and ethylene oligomerization has to be very effective in order to compensate the additional capital cost due to the recovery of ethylene and its further oligomerization.

  • The process has to be economic at much lower capacities of 100 kTon/year, which is currently not possible by using state of the art technologies.

  • The product stream should present several alternatives allowing maximum profitability by adapting the outcome (gasoline/diesel fuels and/or petrochemicals) to fluctuations of the market demand.

A life-cycle analysis was performed and based on the carbon footprint associated with the OCMOL process. A cradle-to-gate approach was taken and a partial product life cycle from resource extraction (cradle) to the factory gate (i.e., before it is transported to the consumer) was performed. The emissions related to the transport and the usage of the final synthetic fuels produced by the OCMOL process, were considered not to be different from other conventional fuels.

Three impact categories were identified where the OCMOL process may contribute to the improvement of the environmental impact:

  1. Energy consumption

  2. Emissions

  3. Transportation.

Emissions related to energy consumption from the OCMOL process are inherently low because of its heat integration. Since oxidative coupling is generating heat that can be used for reforming no extra furnace needs to be installed. The only emissions that are related to energy are due to the consumption of electricity.

The OCMOL process has been designed to be CO2 neutral. Apart from fugitive emission no other emissions were expected. CO2 emissions will also be considerably reduced with the recycling of produced CO2 from the OCM into the RM step. With a carbon efficiency of 92% obtained, the corresponding CO2 emissions were estimated around between 578 and 606 kg CO2/ton of final product and slightly lower than the value of 823 kg CO2/ton found for a natural gas-to-synthetic diesel process.

The impact of logistics, which depends on the distance between a gas field and the OCMOL plant, was low when the process is build close to the gas field. Gas transport could be avoided and replaced by a much more efficient transport of liquid. It has been estimated that each extra kilometer of gas transport corresponds to 0,1 kg CO2/ton of final product. Of course it is not always possible to construct an OCMOL plant close to a remote gas field due its deep-sea location or due to extreme climate conditions. In these cases OCMOL still can reduce the carbon footprint when the plant is constructed in the neighbourhood of the nearest gas storage terminal. In all cases the carbon footprint will be lower than bringing the feedstock via pipelines over a large distance to the market.


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