Furnace Heat Generation

Abstract

The thesis discusses how alternative heat generation for furnaces can be implemented on the Shell Netherlands Refinery to become CO2 neutral by 2050 or sooner. The research analyses the current knowledge, and future alternatives for furnace heat generation and underlines the need for alternative solutions with net-zero emission impact. Furnaces are the equipment that heat process streams before the reactor or distillation column. Hydrogen firing, electrification, biofuel combustion, and heat pumps are the four main topics of alternative technologies that are discussed. The result is a roadmap including all relevant information for the applicability of technologies, developments, value drivers and credible scenarios. Revamping all Pernis’ fired heaters for hydrogen firing is a suitable option and has TRL 6. The ultra-low NOx burners are operational, but hydrogen is not integrated yet as a fuel, and combustion analysers are not field-tested. The blue hydrogen will not be 100% pure, so not all CO2 can be abated. Besides, switching between RFG and hydrogen can cause flame instabilities and a higher thermal NOx emission. The normalised CO2 abatement price against RFG operation, the cost of not emitting a tonne of CO2, is 13 /tCO2. Electrification, such as impedance and immersion heaters, have TRL 7 and are limited to relatively small duties, single-phase, and clean service. Radiant heaters can heat process streams with two-phase and coking services having TRL 2. The concept is proven, but no prototype is tested. Electrical heaters have high efficiencies and might have a yield benefit. However, the showstopper is the plot space availability of the refinery. The normalised CO2 abatement price against RFG operation for electrical heaters is 21 /tCO2. Upgrading biofuel to biomethane allows the gas to be interchangeable with natural gas. Suitable for combustion without any adjustment on the furnace if biomethane is injected into the national natural gas grid. Biomethane combustion, having TRL 7, only impacts the sites emission, and it seems to be an administrative solution, where trading in certificates will be dominating the market. The normalised CO2 abatement price against RFG operation for biomethane is 21 /tCO2. Heat pumps are used in refineries, and they can be used to reduce the furnace load but not to replace the furnace. The potential for replacing fired heaters with TRL 7 heat pumps is low since the maximum operating temperature is 160°C [1]. The development scenarios showing the energy consumption expects that low carbon-intense electricity will expand most, suggesting that electrification is the step forward for SNR. The usage and production of hydrogen tend to increase after 2050, and the amount of biomass is small and will most probably not be an available option for Pernis. Four credible scenarios show that it is possible to abate sufficient CO2. With electrification only, it is impossible to achieve the vision of 2050 due to the plot space constraint. The hydrogen and electrification scenarios are combined in a hybrid scenario, where most CO2 is abated. The net-zero CO2 operation of furnaces requires significant investments and technical developments.