Successful CDU/VDU Project Execution During MRPL Phase III Expansion
C L Sankar Narayanan,Associate Director (Projects)
N Seetaram Das,General Manager (Projects)
Jacobs Engineering India Pvt Ltd

Mangalore Refinery and Petrochemicals Limited (MRPL), a subsidiary of Oil and Natural Gas Corporation Limited (ONGC) operates a petroleum refinery at Mangalore, Karnataka. The Refinery has two existing Crude Distillation units with downstream Hydro-crackers and other refinery units.

MRPL's Phase III expansion plans primarily focus on Upgradation of low value products to high value products, increase in capacity to 15 MMTPA by addition of a new 3.0 MMTPA crude unit, to process cheaper crudes (Sour /Heavy and High TAN), production of petrochemical feed stocks, viz Propylene , Maximise distillate yield, upgrading entire HSD into BS III/IV grade.

CDU/VDU UNIT AND FACILITIES
The unit broadly consists of crude pre-heating section, two stage desalting, post heating section for heat recovery, crude heater, crude distillation column, crude column overhead system, crude column product withdrawal, and cooling system, vacuum distillation column, vacuum column overhead system, ejector system, vacuum column product withdrawal, and cooling system, Naphtha stabiliser column to recover fuel gas and LPG, Naphtha splitter column, product caustic wash, and water wash system wherever required, LPG Amine treating unit, LPG Mercaptan removal unit, and Kerosene treating unit. The following products meeting various specifications leave the unit battery limit Fuel gas, LPG, Light Naphtha, Middle range Naphtha, Heavy Naphtha, Kerosene, Diesel, Heavy Diesel, Vacuum Gas Oil and Short Residue

The unit consists of the following main processing facilities sections:
1) Feed Treatment Facilities
• Electric Desalter: 3.0 MMTPA.
Distilation Facilities
• Atmospheric Distillation Unit - to match 3.0 MMTPA crude distillation capacity.
i. Pre-flash Drum: 3.0 MMTPA.
ii. Crude Column/Stabiliser/Naphtha Splitter.
• Vacuum Distillation Unit: To match 3.0 MMTPA crude distillation capacity .

2) Product Treatment Facilities

• LPG Amine Section: To match 3.0 MMTPA crude distillation capacity.
• Light Naphtha Caustic wash: To match 3.0 MMTPA crude distillation capacity .
• Medium Naphtha Caustic wash: To match 3.0 MMTPA crude distillation capacity.
• Heavy Naphtha Caustic wash: To match 3.0 MMTPA crude distillation capacity .

CDU/VDU UNIT - PROCESS
MRPL Phase III CDU/VDU unit is designed to handle range of API crudes. Essentially, unit is designed for BH –AH type of crudes. The unit has been designed to meet challenges associated not only with variation in crude fractions but also processing high acidic TAN (Total Acid Number) crude. The unit has also aims for providing extensive heat recovery system around the crude preheat trains - leading to more number of heat recovering equipment in the unit. The processing of wide variation of crude led to designing the system with extensive flexibility with provision of bypassing facility across most of the heat exchanger in case of any leakages. Metallurgy selected for this unit is exotic (SS 316L with restriction on minimum concentration of Molybdenum) and proper selection of piping as well as equipment MOC has proved to be a challenge. This also resulted in challenges to procurement strategy and sourcing the exotic materials in quick time. In a single plot area (ISBL)- assimilation of two technology suppliers’ packages have been taken care (EIL and UOP). The new Crude and Vacuum Distillation Unit (Unit No. 310 /311) of MRPL Ph-III Refinery Project is designed to process 3.0 MMTPA of Arab Heavy (AH) and Mumbai High (MH) Crude .



CDU/VDU UNIT - PROJECT HIGHLIGHTS - SAFETY
  • Safety track record at CDU/VDU has been very good and appreciated by MRPL.
  • 9.5 million Man-hours put in at CDU/VDU site by contractors and Jacobs staff.
  • Commissioning of CDU/VDU done in very safe and incident free manner .
  • More than 300 training programmes covering 5000 workmen and staff done in addition to special campaigns like 'Hand safety' and 'Electrical safety'.








VALUE PLUS SUGGESTIONS
1) Value Plus No. 01 – Shifting of Analyser to safe area: Process Stack Analyser for Fired Heater is located in safe area and is provided with split AC without any pressurisation as per the norms.

Tender specification required pressurisation system for Analyser Shelter even though located in Safe Area.

However, Pressurisation is not required if Analyser shelter located in safe area. We have suggested the same to client and they have agreed to this suggestion. -Value Plus savings - Rs 25 lakhs.

2) Value Plus No. 02 - Moving Satellite Rack Room (SRR) closer to the sub-station:Initially SRR room was located outside CDU/VDU phase III plant area. It was located at east side of CDU/VDU plant area.

As per this location estimated cable length required between substation (MCC) and SRR is estimated around 370 metre per run. It was suggested to change the location of SRR inside the CDU/VDU plant area and close to sub-station.

This change of location resulted in saving of cable length around 320 metre per run. Value Plus savings – Rs 26 lakhs.

3) Value Plus No. 03 – Pile Reinforcement: Design of pile reinforcement was submitted by contractor for the load case 'Tension with bending' was considering the equivalent area of inscribed square in 500 mm dia pile.

This was done on account of non-availability of design charts (for circular section for Tension with bending case) in SP-16. This approach was too conservative.

The main bars derived accordingly in each pile as '9 nos - 20 dia- Jacobs suggested a more economic design based Limit State Design concepts considering full diameter and that the same are in use in the industry. Design was revised to main bars in each pile as '4 x 20 mm dia + 4 x 16 mm dia'. Reinforcement bar requirement was reduced by 130 tons which gave an Value Plus Savings of about Rs 55.00 lakhs

4) Value plus No. 04 – Evaluation & Inclusion of additional vendors to project vendor list for (a) Machine Monitoring System and (b) Desalter packages: Tender was issued to vendors initially for (a) Supply and installing of machine monitoring system and (b) supply of Desalter package as per project vendor list. Offers received against both enquiries were significantly high.

Additional vendors therefore were evaluated and included to the vendor list. Tenders were re-issued on a competitive basis to all including the additional vendors. - Value Plus savings - Rs 950. 00 lakhs.

BEST PRACTICES DEPLOYED & TECHNOLOGICAL IMPROVEMENTS ON PROJECT - HIGHLIGHTS.
No. Category/Work Description of work Benefits
1 Alternate technology - Usage of alternate method of weld overlay practice for Cladded Pipes. a) Most of the cladding ie, bonding of SS plates to CS plates – was hitherto being done by the process of explosion bonding. Explosion bonding was being done only at select vendors and was taking time. Also transporting plates back and forth from manufacturer's works was proving to be cumbersome and time taking.
b) Alternate method of cladding was introduced for pipes by way of weld overlay process.
c) Vendors outside India were identified for doing cladding by the weld overlay process using high speed precision weld overlay machines. This was followed by development and approval of welding procedures - to comply with special exotic metallurgy ie, SS316L (2.5 percent Mo) bonding.
Alternative technology/solution identified. Competition introduced giving cost benefit. Improved delivery time.
2 Best Practice –
Integrated approach to
Column fabrication and
Column Internals erection.
a) Combined meeting between Equipment/Piping/Process/Column-vendors/ Internalsvendors/
Client – helped faster resolution of column internal layout issues.
b) All inputs required for engineering were generated internally thus avoiding too much
dependence on vendor data and consequential time delay.
c) Clash with internals and nozzles were avoided by securing the tentative
orientation from vendors for internals and making it suitable for proper pipe
routing. Substantial savings in time as emails and telephonic discussions
were avoided and issues were resolved in person. Re-engineering and
re-work avoided at site.
Less interface issues
between column vendors and column internals vendor.

Considerable time saving.
3 Best Practice – Transport of two nos process columns in one piece to site.
(i) Atmospheric column and (ii) Vacuum column – Over-coming transport challenges.
a) CDU/VDU columns were falling into the Over Dimensional Consignment (ODC) category and length of largest column was 60 m and max. dia was 6 mts. Transportation was done on barge (sea) and trailer (road).
b) Involvement during selection of competent transportation/logistics agencies capable of handling ODC cargo done. Timely erection of equipment thereby avoiding retention of high-cost and heavy-duty cranes that are needed for erection of this equipment.
c) Route surveys done at both ends prior to dispatch.
d) Approvals from roads/railway/electricity/ports/bridges and other authorities planned and taken in advance. A new ODC road was constructed by the client to move all the ODC consignments of the Phase III project. ODC consignments were to cross railway tracks with special permission from railway authorities and within time slot given. As Konkan is one of the busiest rail routes the time slot provided was not more than two hours for each crossing.
e) For overcoming the time constraint, client had designed and pre -fabricated a special structural platform. This was placed over railway tracks using crane provided by the client for each crossing. Since the time duration available for crossing was limited, the positioning of the crane, placement of the platforms had to be done safely in the quickest time to maximise the time available for the crossing. These structural platforms which are in smaller pieces could be easily handled and quickly assembled. Both the ODC consignments were transported through these tracks safely within the allocated time given by railways
Incident/ accident free transportation of columns to site.

Early release of large piping fronts associated with columns.
4 JE Global - Best Practice – Usage of Jacobs Materials Management System (JMMS) tool on MRPL CDU/VDU project. a) JMMS which is used globally in Jacobs was introduced in Indian project. JMMS is windows based and can be easily implemented at multiple locations and at site.
b) JMMS is a very robust planning, tracking and reporting tool for materials management.
c) Material Traceability throughout project’s lifecycle is possible with JMM .
d) Helped in providing focused expediting efforts – made it possible to identify the critical materials from a construction perspective which are needed urgently at site and which will enable ensure continuity and complete major chunks of work at site.
Time and cost savings. Also easy availability/ retrieval of information in single database.

Focused efforts possible.

Skill enhancement.
5 Best Practice -
Usage of Prefabricatedclosed couple hook-ups
a) Used for Flow and pressure transmitter - this has resulted in minimum instrument impulse pipes ie, impulse piping from process tapping to transmitter is kept minimum.
b) These hook ups were modeled in 3D model and reviewed in the presence of prefabricated hook up vendor to ensure proper installing at site later.
Fewer welding joints at site and consequently less radiography.

Fewer fittings used. Thus lower leakage chances.
6 Technology improvement –
Transmission of signals to DCS is designed through Field bus signals Forged steam and condensate manifolds SRR flooring above the cable cellar.
a) The control and monitoring of instrument signals were through Field bus technology instead of conventional 4-20mA transmission.
b) Field bus implementation (FF), the transmission of instruments signals was done in two wires bi-directional for group of around 8 to 12 instruments. In conventional way of transmission (4-20mA0 we have to use 16 to 24 cores of cable . Hence due to FF implementation the quantity of cables are reduced. FF platform provides more info. on Instrument Diagnostic and this will help in easy maintenance. Forged steam and condensate manifold were used instead of site fabricated manifold. This helped in speeding up of the small bore piping work during the last stages of the project reducing site work. To avoid false flooring and associated problems related to false flooring, concrete floors of suitable design was implemented.
Cost savings due to cable reduction.

FF platform has helped in speeding up loop checking procedure.

Time saving.
7 Innovative construction practices –
a) Maximising construction output during rains.

b) Breakthrough in Piling with varying ground conditions.
a) Considering Mangalore is very high rainfall area and spread over four to six months,covering up entire pipe-rack of more than 250 m length with tubular steel and GI sheets was carried out.
b) Proper drainage was planned to ensure that water does not stand on the plot. Maximum possible underground construction work was completed before start of rains.
c) Based on rock that was met during piling these piles were to be terminated. However during the work execution floating rock/boulder was suspected. Additional soil investigations were immediately done and same was confirmed. Therefore special rotary tools were quickly deployed to pierce through the floating rock/boulder and terminate pile in solid rock below. Early deployment of special drilling/cutting tools enabled major time savings. Structure where this work was being done was 118 m tall RCC chimney and was critical.
Large piping fronts got released with time savings.

Pump foundations were possible to construct. Main cable trench and pipe-trenches construction became possible.

Proper load transfer from super-structure to foundation was ensured.
8 Strategic Shift in execution methodology – Change in Mode of Project Execution from LSTK/PMC to hybrid mode ie, EPCM + Packages. a) Project originally envisaged as LSTK/PMC project with PMC overseeing the job. In view of the high costs associated with LSTK /PMC mode, established on basis of actual offers received, alternate project execution methods like EPCM mode was considered.
b) Considering the substantial cost savings that will accrue, client later decided that project will be by Hybrid mode (EPCM + Packages).
c) Enabled faster project completion before the scheduled deadline - for client to take financial benefits. Active client involvement with closer/tighter project monitoring is possible. Lastly incorporating engineering changes / modifications during the implementation of the project becomes possible.
Major cost savings to client.

Major projects which have cost as prime driver can be considered for implementation by - EPCM mode or EPCM + Packages method ie, Hybrid mode of execution.
9 Best Practice –
Project management
The project monitoring was done very closely by both Jacobs and Client. Involvement of client on a daily basis at HO and at site resulted in close follow up and quick decision making. Stationing of client representatives at critical stages project at HO and vendor shops helped in expediting the deliverables.
Client’s rigorous involvement along with the Jacobs to expedite the vendors helped in timely delivery of the project supplies.
Focused interface meetings with client, Technology suppliers, PMC and departments concerned helped in flawless execution of interface activities.
Focused daily site meetings from the initial stages of the project, twice daily meetings during last stages of the project with site contractors with the participation of the client helped in expediting the site work.
 


MID-COURSE CORRECTIONS
1) Statutory compliance: Initially LP steam drum and the Exchanger were ordered on different vendors. However approving statutory authorities considered this to be a complete package and informed that LP Steam Drum and Exchanger along with the associated piping risers and down-comers need to be construed as one system/package. Thus approval needs to be sought from the approving statutory authorities by only one manufacturing agency. Therefore LP steam drum order was cancelled and re-ordered on the Exchanger vendor to comply with the statutory requirement without jeopardising on the overall delivery schedule.

2) Additional small bore contractor introduced: Total quantum of small bore piping was nearly 60,000 inch meters (nearly 15 per cent of total piping work). Also delay in supply of pumps and instruments affected timely release of fronts for small bore piping associated with these. This led to a bunching effect as small bore piping fronts associated with instruments and pumps got quickly released in short span of time. Considering the large quantum and sequence of work a separate contractor exclusively for small bore piping was introduced.

Having an additional contractor essentially meant that the main contractor could focus on large bore and critical process lines (including cladded lines) so that large piping systems could be completed and cleared for hydro-test in quick time.

3) Augmentation for instrument and electrical installation work: Difficulty of instrument and electrical contractors to mobilise resources, materials, necessitated a) additional manpower supply contract (b) direct purchase of materials in his scope, (c) additional supervision from PMC and (d) more resource deployment from client for loop checks etc. Therefore material like instrument tubes, valves, fittings, hoses etc. could be made available to the instrument contractor in good time and the lack of manpower from the contractors end did not impact the schedule adversely.

4) Delay in inputs for engineering: During licensor selection for ATF, necessitated a prolonged discussion with the potential licensors with respect to finalising terms and conditions, requirements etc, which resulted in considerable delay in selecting the package. This resulted in civil contractor waiting for fronts. This was overcome by assumptions; lay out decisions, elevation of equipment being adjusted with skirt length changes etc.

5) Mechanical erection contract: Major order of mechanical erection and piping contract had to be re-tendered for due to some bidders quoting who had failed in the past and had potential to derail the project schedule. To make up for the lost time due to re-tendering, temporary facilities like paved area for spool fabrication, construction power facilities were kept ready prior to contractor’s mobilisation to site.

6) Hiring of DG sets: To expedite the precommissioning of the unit sufficient capacity DG sets were hired and installed in the project site. This helped in plant lighting thereby increasing the output of construction during night, start and expedite the precommissioning activities of motors, SRR and substation.

ACTIONS TAKEN TO PROVIDE SMOOTH WORK FRONTS AT SITE
1) Pump foundations: There are about 150 pumps in the plant and most of them below the pipe rack and adjacent to the column grids of the pipe rack. It was decided that engineering should be completed with all pipe rack and pump foundations in the same foundation network, leaving only the frame details at top on hold till pump details were available. This helped in completing the underground works without waiting for vendor finalisation/inputs for pumps.

2) CDU/VDU columns and associated critical activities: Supply, erection and subsequent works around the columns dictate the completion of the project. This is due to the requirement of hold on structure/foundation in the vicinity of columns for the erection of columns. The central stair tower, ejector structure and equipment there-in, equipment foundations, underground pipe lines, cable trenches were all coming up in the hard stand area (viz lifting trajectory) of the erection crane. About 400 MT of structural work, 50000 in mtr of piping in the vicinity of all piping including large bore Cladded pipes) were coming up in this area.

Construction time was saved considerably by adopting the following engineering/ construction approach rather than the conventional approach:
  • Complete all the foundation and underground piping work in the area in advance.
  • Elevate the hard stand level for the crane by about one meter above the foundation.
  • Level of structure, to provide adequate cushion.
  • Modularise the structure for ejector and central stair tower so that erection and site welding time was substantially reduced. For this splice joints were specially designed, keeping in view the capacity of crane, Appurtenances of the columns like platforms, large dia pipes were attached along with the equipment prior to erection.
  • The heavy duty crane, which was brought in specifically for the column lift was retained to complete the lift-up of all large dia pipes and heavy pieces before dismantling the boom.
3) Piping and mechanical erection work: Piping material front and contractor resources - As in any ISBL unit in a refinery, the piping works at site was the single most important activity that decided the overall completion schedule. The CDU/VDU unit has about 4, 00,000 in mtr of piping. The overall line count was about 4,500 lines. Significantly, there was a substantial amount of small bore piping (roughly about 60,000 in mtr). This can be gauged from the fact that a total quantity of 115 km of pipe was consumed for the 4, 00,000 in mtr piping.

As a strategy substantially higher quantum of pipe material were purchased at the bulk MTO stage although engineering was in progress and a detailed MTO could not be worked at that stage. This was with the client understanding and also suggestion for the same. This helped to a large measure as at all stages of piping fabrication the material front availability was in healthy state and contractor was comfortable fabricating spools in full. Cladded pipes which have a long delivery schedule (about 8 to 10 months) were also ordered in advance both from (a) delivery point of view as well as (b) contingency requirement for future during operations and maintenance.

4) Heat Exchanger Building: The heat exchanger building which houses most of the heat exchangers is a 90 X 15 metre building and with two floors. The construction sequence and schedule was indicating that the roof slab of the building was getting completed after the arrival of many exchangers which are to be located below the roof slab. A proposal was put up to client to convert the RCC slab to a composite slab of steel beams and concrete. Providing decking sheet in roof enabled us to avoid shuttering and scaffolding work. It thus became possible to take the equipment directly into the building even if the slab was not complete. The proposal was accepted by client immediately and it benefited the schedule substantially as equipment erection and piping work could be started before slab completion.

5) Maximising Construction Output during monsoon: The average rainfall during the monsoon periods in this region is more than 4000 mm. It was decided in consultation with client to provide a safe working environment so that following activities could be carried out during monsoon unhindered.
  • Piping Works: - Of the total piping, 32 per cent of pipes are to be laid on pipe rack.
  • Fire Proofing: - Steel structures to be fire proofed.
  • Cable Trench: - Cable-trench activity at grade below pipe rack to be taken up.
  • Pipe Trench: - Underground pipe trench at grade below pipe rack to be taken up.
  • Pump Foundations: - Pump foundations below pipe rack to be taken up.
Considering the above work a proposal was put up to cover the pipe rack with tubular structure and G.I sheets. Similarly all the trenches and underground pipes completed were connected together and rainwater collected and discharged to the outside.

As planned above works could be achieved which otherwise could have affected schedule. Cost incurred in covering the pipe-rack was small as compared to benefits by way of (a) work fronts released and (b) work output achieved. This decision has helped the project as it can be seen from the rain fall statistics of Monsoon 2010 which started from last week of May 2010 and extended up to 15th of December 2010 and had witnessed nearly 5000 mm of rain in the period. Details of works executed with above arrangement during monsoon from 15th May 2010 up to 15th December 2010.