India’s state-owned Bharat Petroleum Corp. Ltd. (BPCL) has completed conversion of the catalytic reforming unit (CRU) at its 12 million-tonne/year Mumbai refinery into a light naphtha isomerization unit as part of the refiner’s program to comply with the Indian government’s nationwide mandate of producing 100% Bharat Stage 4 (BS 4, or Euro 4-equivalent) fuels, which became effective Apr. 1.
Commissioned in March, the isomerization unit will produce an isomerate gasoline blend stock using low-temperature Isolmalk-2 process technology licensed by GTC Technology US LLC, Houston, said GTC, which also provided basic engineering design, catalysts, chemicals, equipment supply, and process guarantees for the project.
In addition to naphtha hydrotreating, fractionation, and isomerization sections, the unit includes a first-of-a-kind installation of GTC’s proprietary Dividing Wall Column (GT-DWC) technology as GT-TDWC, or top-dividing wall column.
Unlike most operating DWCs—with a wall placed in the middle of the column—the GT-TDWC application in the Mumbai unit features the dividing wall extending from the top of a column that has two separate sets of condensing systems to offer greater flexibility in terms of producing different levels of food-grade hexane, the technology licensor said.
Food-grade hexane is a light distillate produced in refineries from special-cut naphtha where the hexane-rich stream is extracted and purified to meet the required specification; the product is mainly used as a solvent in solvent extraction units and other applications.
GTC did not disclose a capacity of the isomerization unit or a contract value for its scope of work on the project.
Project details
As initially planned, the Mumbai isomerization project was to involve conversion of the refinery’s existing CRU into an isomerization unit by maximizing reuse of existing equipment—such as recycle gas compressors, furnaces, and pumps—with the new unit to receive its feedstock from existing unit streams, including light naphtha from the hydrocracker, light reformate from the continuous catalytic reformer (CCR), and the top cut from the modified CRU reformate splitter, according to documents from India’s Ministry of Environment, Forest & Climate Change (EFCC).
Estimated to require a capital investment of 2.5 billion rupees in 2014, the isomerization project—which also was to include a revamp of the refinery’s naphtha hydrodesulfurization unit as well as construction of associated utilities and off sites—was scheduled for completion by December 2016 at an approved cost of 7.25 billion rupees, BPCL said in its latest annual report.
India’s State of Maharashtra Pollution Control Board (MPCB) granted BPCL consent to operate the new light naphtha isomerization and revamped naphtha HDS units at Mumbai on Dec. 7, 2016, under a series of conditions, including the operator’s agreement that it would add a tail gas treating unit to increase sulfur recovery at the refinery to 99.9% by June, MPCB said.
Designed to enable the Mumbai refinery to produce 100% BS 4-quality gasoline—a total of 2.3 million tpy—by the April deadline for a national switch to 100% production of BS 4 fuels as mandated by India’s Auto Fuel Vision & Policy 2025, the isomerization project joins a host of BPCL’s other upcoming as well as previously completed projects to bring the refinery into compliance with the country’s clean-fuels initiative.
A second project under way at the refinery includes construction of a 2.6 million-tpy diesel hydrotreating unit, which also will include setting up associated installations such as an amine regeneration unit and an upgrade of an existing sour water stripper to help maximize capacity of Mumbai’s sulfur recovery unit Trains C and D, BPCL said.
Intended to help meet the April mandate for 100% BS 4-compliant fuel production, the diesel hydrotreating project at Mumbai is scheduled to be fully completed in December at an approved cost of 24.43 billion rupees.
In line with the Indian government’s decision to leapfrog directly to BS 6 (Euro 6-equalivent) compliance by Apr. 1, 2020, BPCL also has launched a project to add a gasoline hydrotreating unit at Mumbai to reach 100% production of BS 6-quality gasoline by the 2020 deadline.
Estimated to cost 5.54 billion rupees, the gasoline hydrotreating project will include construction of a 900,000-tpy hydrotreating unit, as well as proposed revamps of the refinery’s existing 700-tonne/day diesel HDS unit, a 900 tonne/day associated sour water stripper, and a 4,250 tonne/day amine regeneration unit, according to BPCL’s March 2016 project feasibility report.
As of August 2016, BPCL was in the process of selecting technology licensors for the gasoline hydrotreating project, the company told investors.
Granted environmental clearance by EFCC Mar. 20, the gasoline hydrotreater and associated works project is scheduled for mechanical completion in December 2019 and will equip the Mumbai refinery to produce 2.3 million tpy of 100% BS 6-quality gasoline, BPCL and EFCC said.
Engineers India Ltd. is acting as project management consultant on both the diesel and gasoline hydrotreating projects, filings to EFCC show.
Previous projects BPCL completed to ensure Mumbai’s compliance with deadlines under India’s Auto Fuel Vision & Policy include the November 2015 startup of the refinery’s integrated crude and vacuum distillation unit—to replace aging crude distillation units I and II—as well as the March 2014 commissioning of the 1.2 million-tpy CCR.
Contact Robert Brelsford at [email protected].
