Page 6 - LSR on Servocyclotherm G

I n t r o d u c t i o n o f S e r v o c y c l o t h e r m G a t D i g b o i R e f i n e r y An Import Substitution
Introduction of Servocyclotherm G at Digboi Refinery – An Import Substitution

INTRODUCTION

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I In petroleum refining world, waxing (or de-oiling) and dewaxing processes are two sides of the

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same coin. When we manufacture paraffin wax or lube base stock, we normally adopt the process
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s same coin. When we manufacture paraffin wax or lube base stock, we normally adopt the process
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on scraped surface heat exchangers (chillers). All lube stocks, except those from a few highly
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n naphthenic crude oils, must be dewaxed or they will not flow properly at ambient temperatures.

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naphthenic crude oils, must be dewaxed or they will not flow properly at ambient temperatures.

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There are two types of processes in use today. One uses selective hydrocracking process to crack
c bons. The other uses refrigeration to crystallize the wax and
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the wax molecules to light hydrocarrbons. The other uses refrigeration to crystallize the wax and
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s solvent to dilute the oil portion sufficiently to permit rapid filtration to separate the
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mixing with solvent to dilute the oil portion sufficiently to permit rapid filtration to separate the
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D Digboi Refinery uses the second method for production of Praffin Wax.

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wax from the oil. Digboi Refinery uses the second method for production of Praffin Wax. An
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i is given here to explain the working of Feed Scraper Chiller (FSC):

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animation is given here to explain the working of Feed Scraper Chiller (FSC)::
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In Solvent Dewaxing Unit (SDU) of Digboi
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product is the coolant for feed chilling in
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the 2 and 3 feed scraper chiller. This
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Glycol based product is also used for
G l y c o l b a s e d p r o d u c t i s a l s o u s e d f o r
cooling of the solvent i.e. Methyl Isobutyl
c o o l i n g o f t h e s o l v e n t i . e . M e t h y l I s o b u t y l
K Ketone (MIBK) and Blow Gas chilling. etone (MIBK) and Blow Gas chilling. This
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cooling agent is cooled in refrigeration

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Deg C. Thus the coolant takes away heat
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f from processes in Feed Scrapper Chiller rom processes in Feed Scrapper Chiller
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( (FSC), MIBK cooler and Blow Gas chiller.
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The principal steps for deoiling at SDU are
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shown in the flow diagram on the side:
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5 | P a g e