A new naphtha cracking process with the aim of producing more propylene and consuming less energy than existing naphtha thermal-cracking methods has been developed by Chiyoda Corp., as per chemengonline.com.
The company has recently developed a new catalyst based on iron- and gallium-modified MFI-type zeolite (0.5–0.6-nm dia. pore), and successfully used it for the catalytic cracking of naphtha. Iron- and gallium-modification suppresses the polymerization of aromatics, which induce coking that shortens the catalyst life. The company has completed a small-scale demonstration project, which has been supported by the New Energy and Industrial Technology Development Org. (NEDO) since 2015. The technology could be ready for commercial applications in 2021.
The new catalyst was shown to enhance the yield of propylene to 30%, compared to 15% typically obtained in conventional cracking furnaces. The company believes the new catalyst has a longer lifetime, having demonstrated continuous operation of more than 1,000 h in an inexpensive fixed-bed reactor. Other features of the new process include: a 10–15% reduction of naphtha usage; a 60% reduction in energy consumption (by operating at a lower temperature of 565°C); and a reduction in steam consumption by 50% (by eliminating the need for steam injection that is required for operation at 850°C). The company also believes the process can be flexible for producing ethylene-rich or BTX-rich (benzene, toluene, xylenes) production through optimizing the composition of iron and gallium in the catalyst and the cracking conditions.