"METHOD AND APPARATUS FOR RECYCLING HYDROGEN IN REFINING UNIT OF DEVICE FOR PURE TEREPHTHALIC ACID"

• Main Authors: YINGZHI WANG, CHUN ZHANG, RUIKUI YAO, HUATANG ZHOU, WENDE LUO
• Format: Patent
• Language: English
• Published: 15.05.2015
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

A method and an apparatus for recycling hydrogen in refining unit of device for pure terephthalic acid are disclosed. The method comprises: the water vapor in non-condensed gases discharged from crystallization and flash evaporation is removed by cooling and decompressing; the hydrogen with suitable purity formed is recycled. The apparatus comprises a hydrogen compressor and equipment for lowering temperature and pressure. The inlet of said equipment for lowering temperature and pressure is connected with the outlet of the non-condensed gases of the crystallizer group in the refining unit and its outlet is connected with the inlet of the hydrogen compressor. In the invention, because the non-condensed gases discharged from the crystallizer group can be recycled after being treated by lowering temperature and pressure, the existed process and the investment are not changed on the whole, and the method is easy to apply. More importantly, the method of the invention can decrease energy consumption and has significant economic benefit. FIG. 1 1 slurry blending 2 heater group 3 condensate tank 4 condensed water 5 heater 6 leaching tower 7 to the atmosphere 8 crystallizer group 9 mother liquor recovery 10 filtrating and washing 11 to oxidizing unit 12 high-pressure steam 13 flash evaporation gas + H2 14 high-pressure H2 (from hydrogen compressor) 15 hydrogenation reactor 16 desalted water 17 recovered cooling water 18 to hydrogen compressor or hydrogen making equipment 20 cooling water 21 drying 22 leaching 24 PTA product