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INTEGRATED MODEL GUIDED PROCESS OPTIMIZATION OF STEAM CRACKING FURNACES

Periodic Reporting for period 3 - IMPROOF (INTEGRATED MODEL GUIDED PROCESS OPTIMIZATION OF STEAM CRACKING FURNACES)

Reporting period: 2019-09-01 to 2020-11-30

IMPROOF aims at drastically improving the energy efficiency of the radiation section of a steam cracking furnace by at least 20%, and this in a cost-effective way, while simultaneously reducing emissions of greenhouse gases and NOX per ton ethylene produced with at least 25%. Improving the energy efficiency has an immediate pay-out because energy cost counts for approximately 70% of the net production costs in typical ethane- or naphtha-based olefin plants.

In the frame of IMPROOF, the strategic objectives are:
Energy consumption:
o High emissivity coatings emitting in the non-absorbent flue gas spectrum
o Enhanced heat transfer between flue gas and the process by 3D coils
o Novel radiant coil alumina forming alloy tubes that lower the coking rate leading to a lower outside tube temperature
o Novel integrated process design for the IMPROOF furnace
Operating costs:
o Increase production rates per ton olefins produced by increasing furnace combustion efficiency
o Increase production rates per ton olefins produced by selectivity increase using 3D coils
o Increase furnace availability and production rates per ton olefins produced because of reduced coke formation using advanced materials
Reduce CAPEX and OPEX costs of the furnaces by at least 15%:
o Double refractory life, increase process tube life and decrease furnace downtime
o Reduction of NOX and CO2 emissions by at least 25%
o Decrease NOX and CO2 emissions by considering new burner designs, and oxy-fuel combustion
o Decrease net CO2 emission by using biogas and bio-oil as fuel.

The results from IMPROOF show that among the more conventional steam cracking solutions, the combination of alumina rich coil alloy, 3D reactor geometry and high emissivity radiant wall coating is a clear optimum leading to 0.5% reduction in carbon footprint of the studied process. By employing oxyfuel combustion NOx emissions become negligible in such a furnace while Carbon Capture and Storage results in more than 50% reduction of the CO2 emissions. The low emission furnace patented by Technip during IMPROOF allows to reduce CO2 emissions both within the ethylene plant itself as well as in the downstream units handling the exported fuel gas by more than 30% if green electricity is used.
The IMPROOF project was a huge success obtaining all the set objectives and even outperforming the set key performance indicators. This was:
1. improving the energy efficiency of a steam cracking furnace by at least 20%
2. While simultaneously reducing emissions of greenhouse gases and NOX per ton ethylene produced with at least 25%.
As for WP1, CNRS has carried out extensive experimentation collecting experimental data on biogas, bio-oil and natural gas. POLIMI has performed a literature study, updating their reaction mechanism for different types of combustion. POLIMI and UGENT characterized experimentally the composition of the renewable fuels that will be used within this project. This characterization allowed for the selection of surrogate mixtures of a limited number of reference species, whose combustion kinetics are currently being experimentally and theoretically investigated. The use of bio-gas is industrially feasible but from a practical point of view seems not the best option, because of the large cost and emission of new substances to the atmosphere. Therefore, substantial clean-up process is required to make the stream suitable for fuel in an ethylene plant.
JZHC has completed the pilot plant experiments for oxy-fuel combustion. UGENT has completed the coking experiments on the materials provided by S+C. In collaboration with S+C and CRESS initial spectral emissivity experiments have been performed by UGENT. The hot flow pilot plant experiments are being finalized where different coil geometries and materials have been tested. These results provided the vital information for WP4 and WP5 to estimate the overall impacts of these technology changes.
A CFD framework has been constructed by CERFACS in collaboration with UGENT, this numerical approach allows to perform high-fidelity large eddy simulation inside the reactor properly accounting for turbulence and complex chemistry. CERFACS and UGENT have completed the full simulation of the DOW furnaces and the first results have been used to select the geometries that will be demonstrated at DOW. Also, the simulations of the JZHC test furnace are finished, with the latest simulations by UGENT showing a good agreement with the experimental data. The simulation framework seems now a viable tool for further design studies.
DOW operated the 2 CUP furnaces at their Terneuzen site (the Netherlands) to demonstrate the technologies developed in the project. DOW started up the demonstration of technologies in 2019. Field data is analysed by Dow, AVGI and Technip. The demonstration revealed a substantial increase in terms of run lengths between decokes. It is not obvious to quantify the differences in energy consumption. Nevertheless this is aligned with AVGI’s LCA analysis for the evaluated technologies.
Technip has performed together with Dow a technology impact analysis for the Low Emission Furnace. Substantial reduction of CO2 can be achieved especially in green roots plants where the steam cracker flowsheet can be designed for this purpose.
AYMING conducted the Innovation Management Internal Benchmark, identified the Key Exploitation Results / risk assessment and the IP watch. The technology with the highest potential are the 3D reactor technologies made in Aluminium containing material, the Low emissivity furnace patented by Technip and the high emissivity coatings for the furnace walls.
The LCA analysis performed by AVGI shows that oxyfiring technology and low emission furnace technology can lead to substantial reduction of CO2 emissions.
The results will be further disseminated via scientific publications and at conferences. For example three presentations are planned in the upcoming Ethylene Producers Conference in April 2021.
IMPROOF has been operative for more than 4 years. At the same time, the process industry is looking into/embracing combinations of novel technologies. The results were extensively presented at workshops, conferences, at stakeholders such as plastics Europe, universities, companies and in bilateral meetings with academicians and industrial actors. This has boosted interest for the project but also for the technology.
The ethylene industry is also looking at different ways to reduce CO2 beyond the conventional design of ethylene plants. Last June, Dow and Shell announced a collaboration to develop electric cracking technology. In 2019, BASF, Borealis, BP, LyondellBasell Industries, Sabic, and Total announced they would pool their efforts into the Cracker of the Future Consortium. Also BASF disclosed that it is collaborating with the engineering firm Linde on electric furnace technology. The Finnish start-up Coolbrook has its own spin on electrified cracking. The tools and the results of IMPROOF make it possible to make a more accurate comparison of all these different technologies and identify strengths and weaknesses.
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