Melamine touches our lives in more ways than one. A chemical compound, it is used for making adhesives, laminates, tableware, electrical equipment, moulding compounds, flame retardants and much more. A coating of Melamine resin is even used to protect the currency notes from wear and tear. It’s literally in our back pockets.
Gujarat State Fertilizer & Chemicals Limited (GSFC) which has the distinction of being the only Melamine producer in the country awarded a contract for a new Integrated Urea - Melamine plant to L&T Hydrocarbon Engineering (LTHE) on March 29, 2016. GSFC chose Casale SA of Switzerland as the technology licensor for the project. A well-known chemical technology and engineering firm Casale had recently acquired a High-Pressure Melamine process technology from Borealis, an Austrian firm specialising in polyolefins, base chemicals and fertilizers. Known as Low Energy Melamine (LEM™), the process involves conversion of urea directly into Melamine at high pressure without the use of any catalyst.
Melamine project put up by GSFC consists of a 50,000 MTPA Off-Gas Treatment Section producing molten Urea, a 40,000 MTPA Melamine Section producing dry Melamine Powder, Off-Site and Utility section consisting of cooling tower, RO Unit, Caustic Storage Area and a Melamine Bagging Unit. The plant was to be in a brownfield area inside the GSFC Fertilizer Complex at Vadodara.
The scope of LTHE’s work included Extended Basic Engineering, Detailed Engineering including 3D Modelling, Procurement and Supply, Inspection and Expediting, Stores Management, Construction, Pre-commissioning and Commissioning of all the facilities mentioned above.
Melamine Process
Off-gas treatment section (Molten Urea Section) consists of high-pressure reaction section Carbon dioxide and Ammonia to produce urea. The high-pressure carbon dioxide for the process is supplied by a CO2 compressor train consisting of centrifugal and reciprocating compressors both operating in series. Such a system is highly prone to pulsation and requires special dynamic simulation to be carried out on the complete system. To ensure this, and to guarantee design performance of the system, LTHE ordered both compressors from a single supplier viz., Siemens, Germany.
Urea produced in HP section is further concentrated in the MP and LP sections before it is transferred to Melamine unit.
In the Melamine section, molten urea (produced in OGT section) is fed to reactor where it is converted to Melamine in a high temperature, high pressure condition. Melamine solution produced then is further crystalized and processed through rotary vacuum filter and flash dryer package to form dry melamine powder. It is then transported and stored in silos before it is bagged in automatic bagging machine. An automatic palletiser machine packs the melamine bags for onward delivery to consumers.
Engineering
Being the first plant to be designed after technology transfer from Borealis, Casale and LTHE had to work closely to finalise technical specifications, metallurgy, vendor selection and interfaces. Designing a high-pressure Melamine plant in the available plot area was one of the biggest challenges faced by the project team during the detail engineering. 3D models had to be developed at an early stage to finalise all the pipe routings and equipment locations to ensure that everything fitted within the limited space meeting all technical and statutory requirements.
Interfaces between various packages were meticulously managed to ensure that there were no surprises during installation. Additionally, special care was taken to finalise the routing of piping materials of special metallurgy like urea grade, 25-22-2, Alloy 59 etc. so that they were ordered within four months of the project.
Procurement
In all, there were 18 mandatory vendors (mostly European) for the supply of various critical equipment, packages and instruments in the project. Since LTHE had not dealt with these vendors in the past, it caused certain difficulties during engineering and execution. The Melamine plant requires equipment and piping systems of special metallurgy, which are supplied only by a handful of vendors. Sourcing therefore of such materials proved to be a big challenge and procurement teams had to work overtime to ensure timely and accurate supply.
Some of the critical equipment and packages used in the plant included - Molten Salt Unit (from Apaco AG, Switzerland), Thermal Oil Electrical Evaporator (from Heat Systems, Germany), NH3 Superheater (from CASALE SA, Switzerland), Vacuum System Package (from GEA Wiegand GmbH, Germany), Automatic Bagging and Palletizing System (from HAVER & BOECKER OHG, Germany), Crystallizer Vacuum Unit (from GEA Wiegand GmbH, Germany), Vacuum Drum Filter Unit (from Andritz, Germany), Molten Salt Pump (from Friatech, Germany), Thermal Oil Refill Pump (from Klaus Union, Germany), NaOH Pump (from Klaus Union, Germany), NH3 Water Pump (from Klaus Union, Germany), HP Urea Melt Pump (from LEWA, Germany), HP Ammonia Pump, HP Flushing Pump & HP Carbamate Pumps (from Peroni, Italy) and CO2 Centrifugal Compressor (from Siemens, Germany).
Depending on the need, dedicated expeditors were stationed at the works of overseas vendors. Some of the equipment and items had to be airlifted for ensuring timely installation at site.
LTHE also used L&T’s facilities extensively in getting many of the critical equipment manufactured. For instance, the Urea Reactor, Hydrolyzers and Carbamate Receiver were manufactured at L&T’s Hazira shops. At Hazira, the Pipe shop and yard were also utilized for major structural and piping fabrication works.
Construction
Being a brownfield project set inside the GSFC Fertilizer complex meant that the Melamine plant was surrounded on three sides by live facilities. This posed major challenges during plant construction. Initial activities began with the demolition of an existing plant, including the removal of large foundations and underground facilities. The whole area was barricaded to make it safe for construction. The existing underground utilities were diverted to safer locations.
Both OGT and Melamine plants are vertical plants with highest structure going up at 50-meter elevation. The three-storied substation building and three-storied control room cum warehouse buildings were constructed four months ahead of plant’s mechanical completion.
The Melamine Section included intense network of Thermal Oil jacketed piping. This piping provided high temperatures at low pressures in the jackets of Alloy-59 piping spread across the crucial Reaction Section. Casale specified to follow stringent slope requirements & different sequence of construction, testing & pre-commissioning for this piping to avoid any surprises / choking in this section during start-up & commissioning.
Some of the unique strategies adopted during the construction phase of the project were:
• Mobilization of 650 MT Ringer crane for heavy lift erection at site. Most of the erection was done by positioning the crane in the middle of the main road of the fertilizer complex.
• Mobilization of Tower crane to ensure continuous feeding of structural and piping material for erection at higher elevations.
• Installation of temporary elevators for quick movement across plant areas.
• Fabrication of small bore piping at shop (done for the 1st time) so as to save time at site. Typically, this is done in situ.
• Digital initiatives like barcoding for piping spools, use of smart glasses, use of CENTENARY software for pre-commissioning and commissioning of plant.
• Preassembly on ground to minimize work at height.
• “Build it clean” philosophy for ensuring clean pipes and systems thereby minimizing pre-commissioning time.
• Extensive use of “Flawless startup” techniques to ensure that plant is commissioned without glitches.
Complex process plants like Melamine require micro-planning and close monitoring of various activities from design until commissioning. To ensure that proper sequences and priorities were arrived at and adhered to, planning and constructability workshops were conducted at different stages of the project. All this resulted in achieving an average 8% construction progress for six months consecutively, including when the project was at its peak.
Completion
LTHE clocked 7.13 Million LTI free man-hours until project completion. The project team accorded highest importance for HSE and took timely actions to maintain highest safety standards. Several training sessions were arranged during the course of the project execution to train the staff and workmen in various HSE aspects of the project. These initiatives included 727 training sessions, 19 campaigns, 14 safety audits, 33 rounds of senior management walk down, and 34 safety award distribution functions. The project team’s attention to safety even brought it accolades from GSFC.
The mechanical completion of OGT section and OSBL section was achieved on September 11, 2018 with the OGT section getting commissioned a month later on October 20, 2018. The Mechanical completion of the Melamine section was achieved in mid-December with the plant getting commissioned on January 19, 2019.
For LTHE, there couldn’t have been a better way to start off the year!
