06-12-2012, 03:46 PM
AVU and DHDS at IOCL,Mathura
AVU and DHDSw2003.ppt (Size: 1.8 MB / Downloads: 266)
Introduction
Mathura Refinery, the sixth refinery of Indian Oil was commissioned in 1982 with a capacity of 6.0 MMTPA to meet the demand of petroleum products in north western region of the country, which includes National Capital Region.
Only company placed at 83rd position among fortune 500 companies.
Mathura Refinery is the first in Asia and third in the world to receive the coveted ISO-14001 certification for Environment Management System in 1996. It is also the first in the World to get OHSMS certification for Safety Management in 1998.
The major secondary processing units provided were Fluidised Catalytic Cracking Unit (FCCU), Vis-breaker Unit (VBU) and Bitumen Blowing Unit (BBU).
The original technology for these units was sourced from erstwhile USSR, UOP etc.
Soaker drum technology of EIL was implemented in VBU in the year 1993.
For production of unleaded Gasoline, Continuous Catalytic Reforming Unit (CCRU) was commissioned in 1998 with technology from Axens, France.
A DHDS licensed from Axens, France was commissioned in 1999 for production of HSD with low Sulphur content of 0.25% wt (max).
With the commissioning of Once Through Hydrocracker Unit (licensed from Chevron, USA) in July 2000, capacity of Mathura Refinery was increased to 8.0 MMTPA.
Composition of Crude oil
Crude oil is a complex mixture of thousands of hydrocarbons. (i.e paraffin, Napthenes & Aromatics)
Brownish black in Color and colloidal in nature
Contains small amounts of non hydrocarbon impurities in the form of organic compounds of sulphur, oxygen, nitrogen, metals, water and salts.
CDU OPERATIONS
1. The desalted crude is Preheated to about 180-200 deg C and fed to Prefractionator column
2. The purpose of prefractionator is to separate the lighter hydrocarbons at relatively lower temperature so as to reduce heat energy requirement across furnace and to reduce the main fractionator overhead vapour load
3. Prefractinator are typically used in revamps for energy conservation and unit capacity enhancement
Prefractionator Operating condition
Top Temperature range= 120-130 deg c
Pressure= 1.5-3.0 kg/cm2g
4. The Pre-fractionator column bottom is fed to Fractionator column after
heating to 360 –370 Deg C in Heat Exchanger train & Furnace.
Significance of Vacuum Distillation
RCO from CDU is "heavy", and the separation of this stream into various fractions would normally require more energy and higher temperatures.
Higher hydrocarbons promotes coking reactions at more than 380 deg c at atmospheric pressure fouls the furnace tubes.
To reduce the amount of energy input required, and to recover the valuable products from RCO without cracking, it is distilled under vacuum.
The vacuum condition reduces the boiling point of the RCO and the fractions are separated relatively at lower temperature led to energy saving and reduces fouling of the furnace tubes