In our hydrocraker unit in first stage we have VGO and HCGO. We maintain ratio 70:30. If we increase the percentage of HCGO there is any effect in reaction and hydrogen consumption? And how to maintained?
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15/05/2017
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Sarath Konda, DuPont India, sharathsatya@gmail.com
Kindly note 1st bed exotherm will be increase significantly and it is important to control max DT in the beds. Also Delta P across the be will increase due to higher H2/HC ratio and higher vaporization.
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10/04/2017
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Carlos Hugo Mendiondo, CHM Consult, carloshugomendiondo@gmail.com
The mean objective of Hydrocracker first stage is to eliminate nitrogen and sulphur compounds .More critical is the nitrogen in especial those linked to very condensed polyaromatics rings .It is so cause these compunds are adsorbed very strongly on acid sites of downstream hydrocracking catalyst deactivating this important function .These kind of compounds are present in HCGO much more than HVGO and are very hard to eliminate so that if you increase the amount of coker GO probably you will send more of these compounds toward second stage .How much of HCGO you can process in your unit ?It will depend of H2 pp , LHSV, catalyst type , catalyst grading ,plant configuration etc so that the licensor of the technology will give you the best answer in this case.Nevertheless you can relieve externaly the effects of HCGO if you have margin to decrease the end point of this cut in your Coker unit because the polyaromatics are sharply decreased when decrease the end point of HCGO .Typically Coker units are designed to more distillates and less coke pet but regrettably it increased deeply the end point of HCGO.
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09/04/2017
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Carlos Mendiondo, CHM Consult, Carloshugomendiondo@gamil.com
The first stage of hydrocracking process objective is reducing nitrogen and sulphur compounds .The first objective of this section is to eliminate the very hard nitrogen associated with very condensated aromatics rings that are bodies that are adsorbed strongly over acid sites deactivating acid sites of hydrocracker catalyst at the second stage Those bodies are tipicaly present in HCGO much more than heavy vacuum gas oil.The partial pressure of H2 and LHSV ,catalyst grading and the plant configuration are important design parameters and it will be feasible or not your new operation status without affecting the down stream acid catalyst .You can consult it with your licensor who know very well such limits of the technology . Externally you can alleviate the severity of the operation if you have margin to move down he end point of CHGO of you cokers making it more light ,because hight end point strongly increase polyaromatics compounds .Typically they are designed to maximum distillates and minimum coke pet. It has very hight impact on feedstocks quality.
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05/04/2017
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Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
Generally the ratio of VGO and HCGO as a feed to hydrocracker will be in the ratio 20% to 25 % . Higher the ratio of HCGO in the feed more is the consumption of Hydrogen , since HCGO contains more aromatics , cracked product , with high nitrogen content around 4000 to 5000 ppm , basic nitrogen in the range of 1500 ppm . Asphaltenes content and polycyclic aromatics content is also very high , tendency to deposit coke on the catalyst. Catalyst cycle length can reduce. Sulphur content is also higher , depending on the crude oil source.
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03/04/2017
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Ganesh Maturu, Self, maturu.ganesh@gmail.com
If we increase HCGO beyond design limit as against assumptions made during catalyst grading...
1. HCGO contains almost 70- 80% aromatics and sulfur level is also high compared to VGO. Hence it requires high WABT and high deactivation for meeting required product specs.
2. Since it contains high aromatics and high sulfur and nitrogen, it requires high H2 to meet required prod specs.
3. Since it is hydrocracker... pressure would be higher and reactor catalyst system may be stable but exotherm in reactor beds increases and quench requirement also increases. overall recycle gas flow requirement increases. make sure enough margin available in recycle gas compressor.
4. Possibility of reduction in h2 partial pressure because of more cracked material and lighters.
5. HCGO contains lot of impurities and having less grading in existing reactor would cause high pressure drop. Have detailed metal analysis and ensure it is less than design limit.
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01/04/2017
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Manoj, Lummus Global Pte. Singapore, parasharmk@yahoo.com
If we increase HCGO beyond design limit as against assumptions made during catalyst grading...
1. HCGO contains almost 70- 80% aromatics and sulfur level is also high compared to VGO. Hence it requires high WABT and high deactivation for meeting required product specs.
2. Since it contains high aromatics and high sulfur and nitrogen, it requires high H2 to meet required prod specs.
3. Since it is hydrocracker... pressure would be higher and reactor catalyst system may be stable but exotherm in reactor beds increases and quench requirement also increases. overall recycle gas flow requirement increases. make sure enough margin available in recycle gas compressor.
4. possibility of reduction in h2 partial pressure because of more cracked material and lighters.
5. HCGO contains lot of impurities and having less grading in existing reactor would cause high pressure drop. Have detailed metal analysis and ensure it is less than design limit.
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