A New Turbomachine for Clean and Sustainable Hydrocarbon Cracking

Decarbonising highly energy-intensive industrial processes is imperative if nations are to comply with 2050 greenhouse gas emissions. This is a significant challenge for high-temperature industrial processes, such as hydrocarbon cracking, and there have been limited developments thus far. The novel concept presented in this study aims to replace the radiant section of a hydrocarbon cracking plant with a novel turbo-reactor. Rather than using heat from the combustion of natural gas, the novel turbo-reactor can be driven by an electric motor powered by renewable electricity. Switching the fundamental energy transfer mechanism from surface heat exchange to mechanical energy transfer significantly increases the exergy efficiency of the process. Theoretical analysis and numerical simulations show that the ultra-high aerodynamic loading rotor is able to impart substantial mechanical energy into the feedstock without excess temperature difference and metal temperature magnitude. The required enthalpy rise can be supplied within a reactor volume 500 times smaller than that for a conventional furnace. A significantly lower wall surface temperature, supersonic gas velocities and a shorter primary gas path enable a controlled reduction in the residence time for chemical reactions, which optimises the yield. For the same reasons the conditions for coke deposition on the turbo-reactor surfaces are unfavourable, leading to an increase in plant availability. This study demonstrates that the mechanical work input into the feedstock can be dissipated through an intense turbulent mixing process which maintains an ideal and controlled pressure level for cracking.

Understanding the Catalytic Activity of Microporous and Mesoporous Zeolites in Cracking by Experiments and Simulations

Porous zeolite catalysts have been widely used in the industry for the conversion of fuel-range molecules for decades. They have the advantages of higher surface area, better hydrothermal stability, and superior shape selectivity, which make them ideal catalysts for hydrocarbon cracking in the petrochemical industry. However, the catalytic activity and selectivity of zeolites for hydrocarbon cracking are significantly affected by the zeolite topology and composition. The aim of this review is to survey recent investigations on hydrocarbon cracking and secondary reactions in micro- and mesoporous zeolites, with the emphasis on the studies of the effects of different porous environments and active site structures on alkane adsorption and activation at the molecular level. The pros and cons of different computational methods used for zeolite simulations are also discussed in this review.

A New Turbomachine for Clean and Sustainable Hydrocarbon Cracking

Decarbonising highly energy-intensive industrial processes is imperative if nations are to comply with anthropogenic greenhouse gas emissions targets by 2050. This is a significant challenge for high-temperature industrial processes, such as hydrocarbon cracking, and there have been limited developments thus far. The novel concept presented in this study aims to replace the radiant section of a hydrocarbon cracking plant with a novel turbo-reactor. This is one of the first major and potentially successful attempts at decarbonising the petrochemical industry. Rather than using heat from the combustion of natural gas, the novel turbo-reactor can be driven by an electric motor powered by renewable electricity. Switching the fundamental energy transfer mechanism from surface heat exchange to mechanical energy transfer significantly increases the exergy efficiency of the process. Theoretical analysis and numerical simulations show that the ultra-high aerodynamic loading rotor is able to impart substantial mechanical energy into the feedstock without excess temperature difference and temperature magnitude. A complex shockwave system then transforms the kinetic energy into internal energy over an extremely short distance. The version of the turbo-reactor developed and presented in this study uses a single rotor row, in which a multi-stage configuration is achieved regeneratively by guiding the flow through a toroidal-shaped vaneless space. This configuration leads to a reduction in reactor volume by more than two orders of magnitude compared with a conventional furnace. A significantly lower wall surface temperature, supersonic gas velocities and a shorter primary gas path enable a controlled reduction in the residence time for chemical reactions, which optimises the yield. For the same reasons, the conditions for coke deposition on the turbo-reactor surfaces are unfavourable, leading to an increase in plant availability. This study demonstrates that the mechanical work input into the feedstock can be dissipated through an intense turbulent mixing process which maintains an ideal and controlled pressure level for cracking. Numerical calculations show that the turbulence intensity increases by nearly an order of magnitude relative to that in a industrial radiant reaction tube, which can be favourable for accelerating the chemical kinetics.

Kraft Lignin Ethanolysis over Zeolites with Different Acidity and Pore Structures for Aromatics Production

To utilize its rich aromatics, lignin, a high-volume waste and environmental hazard, was depolymerized in supercritical ethanol over various zeolites types with different acidity and pore structures. Targeting at high yield/selectivity of aromatics such as phenols, microporous Beta, Y, and ZSM-5 zeolites were first examined in lignin ethanolysis, followed by zeolites with similar micropore size but different acidity. Further comparisons were made between zeolites with fin-like and worm-like mesoporous structures and their microporous counterparts. Despite depolymerization complexity and diversified ethanolysis products, strong acidity was found effective to cleave both C–O–C and C–C linkages of lignin while mild acidity works mainly in ether bond breakdown. However, when diffusion of gigantic molecules is severe, pore size, particularly mesopores, becomes more decisive on phenol selectivity. These findings provide important guidelines on future selection and design of zeolites with appropriate acidity and pore structure to promote lignin ethanolysis or other hydrocarbon cracking processes.

ANALISIS PENGARUH PANJANG PIPA HYDROCARBON CRACKING SYSTEM (HCS) TERHADAP PERFORMA MESIN SEPEDA MOTOR

Pada era sekarang ini cadangan minyak bumi semakin menipis, terutama bahan bakar yang berasal dari fosil yang penggunaannya semakin meningkat tajam dengan adanya perkembangan di dunia otomotif dan industri. Oleh karena itu untuk mengurangi pemakaian bahan bakar dengan cara menggunakan alternatif energi baru atau dengan cara melakukan penghematan bahan bakar dengan menggunakan Hydrocarbon Cracking System (HCS).Penelitian ini bertujuan untuk memperoleh data perbandingan unjuk kerja motor bakar 4 langkah dengan variasi panjang pipa katalis yaitu 300 mm, 450 mm dan 500 mm dengan diameter dalam 2 mm dengan bahan bakar premium. Dari hasil penelitian yang dilakukan pada torsi, penggunaan katalis dengan panjang 550 mm menghasilkan torsi tertinggi dibandingkan dengan tanpa menggunakan katalis (standart) yang hanya mencapai torsi maksimum sebesar 4.60 NM sedangkan pada daya penggunaan katalis dengan panjang 550 mm menghasilkan daya tertinggi dibandingkan dengan tanpa menggunakan katalis (standart) yang hanya mencapai daya maksimum sebesar 5.90 hp. Sedangkan pada penggunaan bahan bakar, dengan penambahan katalis terjadi penghematan bahan bakar. Penghematan tertinggi terjadi pada penggunaan pipa katalis dengan panjang 450 mm baik dengan putaran 4000 rpm, 5000 rpm maupun 6000 rpm di bandingkan dengan tanpa pipa katalis. hanya terjadi pada putaran 7000 rpm sedangkan pada putaran 8000 Rpm dan 9000 Rpm penghematan tertinggi pada penggunaan pipa katalis dengan panjang 550 mm.