بازيافت كاتاليست هاي مستعمل واحد كلاوس پالايشگاه هاي گاز طبيعي و استفاده از آن ها جهت سنتز جاذب هاي كامپوزيتي پوشيده با پلي پيرول به منظور حذف سرب از محلول آبي

Recycling the Spent Catalysts of Claus Unit in Natural Gas Refineries and Their Application for Synthesis of Composite Adsorbents Coated by Polypyrrole for the removal of lead ions

زﻣﯿﻨﻪ و ﻫﺪف: ﻓﺮاﯾﻨﺪﻫﺎي ﮐﺎﺗﺎﻟﯿﺴﺘﯽ در ﺻﻨﺎﯾﻊ ﻧﻔﺖ و ﮔﺎز و در زﻣﯿﻨﻪ ﭘﺎﻻﯾﺶ، ﺧﺎﻟﺺ ﺳﺎزي و ﺗﻮﻟﯿﺪ ﻣﺤﺼﻮﻻت ﺑﺎ ارزش اﻓﺰوده ﺑﯿﺶ ﺗﺮ از اﻫﻤﯿﺖ ﺑﺴﯿﺎر زﯾﺎدي ﺑﺮﺧﻮردارﻧﺪ. در اﯾﻦ ﻣﯿﺎن اﺣﯿﺎي ﮐﺎﺗﺎﻟﯿﺴﺖ ﻫﺎي ﻣﺴﺘﻌﻤﻞ و اﺳﺘﻔﺎده از آن ﻫﺎ ﻣﯽ ﺗﻮاﻧﺪ ﮐﻤﮏ ﺷﺎﯾ ﺎﻧﯽ در رﻓﻊ ﻣﻌﻀﻼت ﻣﺮﺑﻮط ﺑﻪ ﻧﮕﻬﺪاري اﯾﻦ ﻧﻮع ﭘﺴــﻤﺎﻧﺪﻫﺎ در ﭘﺎﻻﯾﺸــﮕﺎه ﻫﺎي ﮐﺸــﻮر ﻧﻤﺎﯾﺪ. در اﯾﻦ ﺗﺤﻘﯿﻖ اﺣﯿﺎي ﮐﺎﺗﺎﻟﯿﺴــﺖ ﻫﺎي ﻣﺴــﺘﻌﻤﻞ ﮐﻼوس در واﺣﺪ ﺑﺎزﯾﺎﻓﺖ ﮔﻮﮔﺮد )واﺣﺪ SRU( و اﺳﺘﻔﺎده از آن ﺟﻬﺖ ﺗﻬﯿﻪ ﮐﺎﻣﭙﻮزﯾﺖ آﻟﻮﻣﯿﻨﺎ/ﭘﻠﯽ ﭘﯿﺮول ﺑﻪ ﻋﻨﻮان ﺟﺎذب ﻣﻨﺎﺳﺐ ﺟﻬﺖ ﺣﺬف ﺳﺮب از ﻣﺤﻠﻮل ﻫﺎي آﺑﯽ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. روش ﺑﺮرﺳﯽ : اﺣﯿﺎي ﮐﺎﺗﺎﻟﯿﺴﺖ ﻫﺎ ﺑﻪ دو روش اﺳﺘﻔﺎده از آب داغ و اﺳﺘﻔﺎده از ﻣﺤﻠﻮل ﺳﻮد و ﺳﭙﺲ ﺣﺬف ﮐﮏ ﺑﻪ روش ﺣﺮ ارﺗﯽ اﻧﺠﺎم ﺷﺪ. ﺷــﻨﺎﺳــﺎﯾﯽ و آﻧﺎﻟﯿﺰ ﮐﺎﺗﺎﻟﯿﺴــﺖ ﻫﺎي اﺣﯿﺎ ﺷــﺪه ﺑﻮﺳــﯿﻠﻪ ﺗﮑﻨﯿﮏ ﻫﺎي XRF ،XRD و FTIR و BET ﺻــﻮرت ﮔﺮﻓﺖ. ﺳــﻨﺘﺰ ﮐﺎﻣﭙﻮزﯾﺖ آﻟﻮﻣﯿﻨﺎ/ﭘﻠﯽ ﭘﯿﺮول ﺑﺎ اﺳﺘﻔﺎده از ﭘﻠﯿﻤﺮﯾﺰاﺳﯿﻮن درﺟﺎ روي ﺑﺴﺘﺮ آﻟﻮﻣﯿﻨﺎي اﺣﯿﺎ ﺷﺪه ﺻﻮرت ﮔﺮﻓﺖ و ﻗﺎﺑﻠﯿﺖ آن ﺟﻬﺖ ﺣ ﺬف ﺳﺮب از ﻣﺤﻠﻮل آﺑﯽ درﺷﺮاﯾﻂ ﻣﺨﺘﻠﻒ اﻋﻢ از pH ﻣﺤﻠﻮل، ﻏﻠﻈﺖ ﻫﺎي ﻣﺨﺘﻠﻒ ﺳﺮب، دﻣﺎ و ﻣﻘﺪار ﺟﺎذب اﻧﺪازه ﮔﯿﺮي ﺷﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﺑﻪ د ﺳﺖ آﻣﺪه ﻧ ﺸﺎن داد ﮐﻪ اﺣﯿﺎي ﮐﺎﺗﺎﻟﯿ ﺴﺖ ﻫﺎ ﻣﻮﺟﺐ ﺣﺬف ﻧﺎﺧﺎﻟ ﺼﯽ ﻫﺎ و ﮐﺎﻫﺶ ﮔﻮﮔﺮد ﺑﻪ ﻣﯿﺰان ﻗﺎﺑﻞ ﺗﻮﺟﻬﯽ ﮔﺮدﯾﺪ و ﺗﺄﺛﯿﺮي ﺑﺮ ﺳﺎﺧﺘﺎر ﮐﺎﺗﺎﻟﯿﺴﺖ ﻧﺪاﺷﺖ. ﺳﻄﺢ وﯾﮋه ﮐﺎﺗﺎﻟﯿﺴﺖ از m2/g 84 در ﻧﻤﻮﻧﻪ ﻣﺴﺘﻌﻤﻞ ﺑﻪ m2/g 186 اﻓﺰاﯾﺶ و ﻣﻘﺪار ﮔﻮﮔﺮد از 2/53%ﺑﻪ 0/005-0/007% ﮐﺎﻫﺶ ﯾﺎﻓﺖ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﮐﺎﻣﭙﻮزﯾﺖ ﺳﺎﺧﺘﻪ ﺷﺪه ﺗﻮاﻧﺎﯾﯽ ﺑﺎﻻﯾﯽ در ﺣﺬف ﯾﻮن ﻫﺎي ﺳﺮب از آب دارد. رﻓﺘ ﺎر ﺟﺬﺑﯽ ﺑﺮاﺳﺎس ﻫﻢ دﻣﺎي ﻻﻧﮕﻤﻮﯾﺮ و ﺳﯿﻨﺘﯿﮏ ﺷﺒﻪ ﻣﺮﺗﺒﻪ دوم ﺗﻌﯿﯿﻦ ﮔﺮدﯾﺪ.

Abstract Background and Objective: Catalytic processes in oil and gas industries are very important for refining, purification and production of useful compounds. Regeneration of spent catalysts is interested due to their environmental problems as solid wastes in the refineries. Activated alumina is a very useful catalyst in gas refinery for conversion of hydrogen sulfide to the elemental sulfur in Claus unit. In this paper regeneration of spent catalyst of Claus process in Sulfur Recovery Unit (SRU) and application of it for synthesis of polypyrrole/Al2O3 composite as an adsorbent of lead ion was investigated. Method: Catalyst regeneration was performed via washing by water or caustic washing and then thermal process. Characterization and analysis of catalysts were performed by XRF, XRD, FTIR, and BET measurements. Polypyrrole /Al2O3 composite was synthesized by in situ polymerization and used for removal of lead ions in batch experiments and different values of pH, lead concentration and temperature. Findings: Results showed that regeneration process caused to removal of impurities and sulfur without any change in the catalyst structure. Specific area of catalyst increased from 84 m2/g in spent catalyst to 186 m2/g in regenerated sample while the sulfur content decreased from 2.53% to 0.005-0.007%. Discussion and Conclusion: The results indicated that the composite showed high ability for lead removal. Adsorption behavior was determined as Langmuir isotherm and pseudo-second order kinetic.