1 ion olefin nhẹ hơnOlefin Hấp thụ protonvào liên kết đôi Ion
6.7. Quá trình isome hóa cơng nghiệp
Hydro
Khí
Sản phẩm Ngun liệu
Hình 6.20. Isome hóa của BP
Chú thích:
1. Lị gia nhiệt ngun liệu; 2. Lị phản ứng;
3. Tách khí;
4. Cột ổn định 5. Máy nén khí; 6. Ngưng tụ.
Zeolite catalysts display activity at higher temperatures comparing with catalysts of the other types and, therefore, low octane numbers of isomerate (76-78 RON). However, they have high resistance to poisons in feed and ability to regenerate in unit reactor completely. In the technological scheme of this process fire heaters for gas-feed mixture heating up to reaction temperature are provided. Sufficiently high hydrogen to hydrocarbon feed ratio is required (along with isomerization hydrogen is spent for feed dearomatization), therefore a compressor for recycle hydrogen gas supply and a separator for hydrogen gas separation are necessary.
Ng̀n :https://nefthim.com/manual/Isomerization-process/
Hình 6.21. Isomerization process flow diagram over zeolite catalysts
Catalysts based on chlorinated aluminum oxide are the most active and provide high yield and octane number of isomerate. It is necessary to say that during isomerization such catalysts loose chlorine, as a result activity decreases. Therefore, injection of chlorinated compounds (usually CCI4) into feed is provided to maintain high catalyst activity. After that caustic treatment to remove organic chlorine in special scrubbers is necessary. A big disadvantage is that this type of catalyst is very sensitive to catalytic poisons (oxygen-containing compounds, water, nitrogen, sulfur, metals) and requires very accurate feed preparation. Chlorinated catalysts do not regenerate, and their service life is 3-5 years.
Catalysts based on sulfated metal oxide (oxide catalysts) have become popular recently, because they combine high activity and resist to catalytic poisons action, are able to regenerate. As well as for zeolite catalysts, there is a need for compressor to supply recycle hydrogen gas (picture 3), however there is no necessity in chlorine supply, adsorptive feed treatment and caustic treatment of hydrocarbon gas.
Hình 6.23. Isomerization process flow diagram over oxide catalysts with pentane and hexane recycle
Hình 6.24. Light straight run naphtha isomerization process flow diagram.
Hình 6.25. Uop Penextm process.
Nguồn: http://hassanelbanhawi.com/processes/isomerization-process/
https://www.honeywell-uop.cn/isomerization-penex/
Hydrocarbon Once-through – the light naphtha passes the isomerization reactor only once. Normal paraffins are converted to iso parafins but the conversion is limited by equilibrium. Typical product octanes are in the 80-84 RONC range.
Nguồn: https://www.honeywell-uop.cn/uop-isomerizationdih-flow-sheme/
Isomerization/DIH – a de-isohexanizer is used to recover and recycle unconverted normal hexane and low octane hexane isomers to the reactor system. RONC values of 87-89 can be achievef.
Hình 6.26. DIP/Isomerization/Super DIH 90-93 RONC
Nguồn: https://www.honeywell-uop.cn/dipisomerizationsuper-dih-flow-scheme-2/#