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How do we maintain the purity of Recycle hydrogen in a Diesel Hydrotreating unit?
 
Answers
01/11/2011 A: Satish Angadi, Haldor topsoe, satish.angadi@gmail.com
Basically Make-up gas purity is determining factor, higher the better.
One can purge some of the recycle gas to raise the purity. How much you can purge will be decided by your make-up gas compressor capacity.
31/10/2011 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Increase make up/purge gas rate or increase purity of make up gas. If you are not amine treating the recycle gas, adding an amine treater will increaase hydrogen purity of the recycle gas by removing H2S.
31/10/2011 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
It is desirable to maintain purity of hydrogen in RG for partial pressure reasons. Hydrogen sulfide is removed by amine wash. Make up hydrogen purity is maintained with PSA Hydrogen. Greater supply of PSA hydrogen and maintaining set pressure at separator is helpful sometimes.
31/10/2011 A: Raghavendra Sangam, Libra Techcon Ltd., rsangam0504@yahoo.co.in
There are molecular-sieve based swing adsorption/desorption units for purifying the hydrogen from reactor off-gas. Also, there are membrane based separation systems. Check out which one is suitable for your unit based on purity requirements and the volumetric flow.
28/10/2011 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Increasing H2/HC ratio increases recycle purity. Reducing separator temperature increases recycle purity. In some units, however, the separator temperature is maintained higher than minimum to avoid an emulsion between hydrocarbon and water in the separator.