Value Engineering Considerations in building Hydrocarbon Complexes

Overview

Hydrocarbon complexes pertaining to Refineries, Petrochemical, Gas Processing Facilities, Gas Integrated Hydrocarbon Complexes etc, are all significant on account of being highly technology and capital intensive. Experience reveals, that in absence of a concrete knowledge or experience based considerations, several issues remain unaddressed, during conceptual planning and therefore, are noticed when the event has actually occurred. This leads to both schedule and cost implications, thereby leading to an un-optimized solution towards the objective function.

Every stage of Project Implementation warrants that pre-emptive action ought to be taken. As is popularly known, caution is better than valour, it is important therefore, that experience and enriched feedback is utilized for implementing projects.

Experience reveals, that while the intentions are invariably noble, experience is often, not shared in the manner that it becomes simply useful for personnel at all levels in implementing organizations. In general, as people grow in organizations, they either have a tendency of taking things for granted or perhaps, loose the verve to communicate, such that, the learnings remain largely non disseminated. As a result, experience often remains in pockets and is neither discussed nor disseminated amongst the various stake holders.

Mega installations are a pride of the Nation and warrant that the soul of the project is always served with the best. Consequently, the tendency of sharing only within limits, or need to know basis or being circumspect about knowledge and its wide distribution, remains an issue. It goes without saying, that ultimately, it is the human being who is behind these particular acts. 

In general, people have a natural tendency of hiding more than sharing. Demonstration of knowledge on areas, where some know and others do not, is actually a matter of great discussion. This perhaps, has especially to do something with the spiritual upbringing and development of individuals as to how they approach a subject. It is important, however, that critical knowledge emanating out of experience must be shared.  In fact, it is important that people who have spent more than 20-25 years to gain expertise, is incumbent upon all of them, to have a universal approach towards knowledge sharing and experience dissemination. Incidentally, it requires great focus, great values and the sense of balance and equity, which would enable individuals to excel in the respective areas of functioning but more than that, being pragmatic and    magnanimous to share it simultaneously for the benefit of all is the real essence.  This of course, is an area of improvement. Soulful giving is a natural tendency which takes time and noble recourse to be taken forward.

Experience suggests that people sharing information out of volition have always been a rare and scarce commodity. Consequently, youngsters, in particular, often have to go through the arduous ordeal to find avenues of learning to grow and accumulate wisdom through a process of struggle. While there can never be substitute for industriousness, hard work, dedication and perseverance, the possibilities of expanding the working knowledge base of individuals at various levels could magnify, once critical and relevant knowledge, is shared with them uninhibitedly. This is a noble objective, as well as the cardinal principle around which, leadership and its effectiveness, is actually to be judged. 

One of the critical areas, where this knowledge can be simultaneously passed down the line is perhaps, Value Engineering through critical idea sharing. A concept so dear to an engineer and so effectively to be utilized as a management tool, to provide excitement and joy amongst the working teams. How should this information and value engineering concepts, be passed down, is a matter of critical importance. While numerous books and literature are available on the subject, we in our entire career, never came across a handy check list, which can be utilized in the hydrocarbon sector, for individuals to consider specific issues in the various stages of the Project viz. conceptualization, development, maturity, implementation, completion to operation.

A check list claiming to be complete in all respects can only be considered as utopia. However, effort certainly can be made by which, individuals experience can be passed down the line for all to savour the benefit of the same. The list could always be expanded with experience flowing in from all other quarters unrestrictedly.

Implementation of projects involves a huge number of interfaces and wide variety of stake holders, chief amongst them being the client, consultants, licensor, vendor and contractor’s sub-agencies etc etc. All of them have a significant role to play and perhaps, all of them need to be kept informed about the nuances of design, engineering, procurement, construction and commissioning. The assumption that you know and others should follow is a principle which needs to be rejected. Our own approach towards implementation has been, dissemination of knowledge, irrespective of the recipient, as the central core objective. It has remained a welcome personal experience and therefore, this article. 

The Article addresses the concept of evolution of a project from start to maturity of Engineering, and therefore, the experience and feedback cannot be related to a particular area. It has to cut across all the segments. We have briefly attempted to list some important learnings in a manner which, could perhaps be utilized somewhat, as a check list for value engineering based SWOT in early various stages of the project, more so, during the conceptualization and initial phase of the project, where, it is extremely critical to examine options and arrive at the most significant optimal solution.

Conceptualization of a Hydrocarbon Complex  

 1.    Consider integrated saturated and unsaturated gas plant. Reasons for not following the same must be recorded. This is highly capex, plot space and optimization related matter.

2.    In case the complex envisages a DCU, destination of the streams from the same must be carefully considered, particularly Coker naphtha. One recommendation could be to consider Coker naphtha to be hydro-treated for routing to an Olefin Complex or hydro-treating and splitting into light naphtha for utilization as fuel + FEED to a hydrogen plant and heavy naphtha to be reformed as a gasoline blender.

3.    The compression facilities for the hydrogen requirements in the hydro processing facilities, such as DHDT, VGO Hydro-treater, a hydrocracker or a Resid Hydrocracker must be centralized. It is incidental, that the pressure at which hydrogen is required in each of these units is at different levels.  Typically, reciprocating compressors are utilized for compressing hydrogen utilization in various process facilities through a multi stage compressor. Other stage pressure levels of the compressors must be so adjusted that the process requirements in the complex are appropriately addressed. This will minimize machines, piping and capex and lead to higher level of optimization though, of course, it will enhance the operational risks associated with the centralization of facility. However, sparing of compressors can appropriately address the risk.

4.    Most of the facilities in the refinery need to be hot integrated. Also several process units are required in a complex, consequently depending upon the various upset scenarios, intermediate storages are provided. A critical decision needs to be made with respect to the hot integration of units and supplementing of feed to a process unit from storage in an event when the upstream unit providing feed to another unit is down. In our experience, since high reliability is ensured in process facilities, it is important that maximum units must be hot integrated to save energy. Energy efficiency of the process facilities is expected to magnify based on hot integration considerations of the plant. This will reduce the Opex of the plant considerably and enhance optimization significantly.

5.    Low level heat recovery in process facilities has to be a central objective. It is noted that considerable amount of low level heat is rejected to air and cooling water both in the refineries and petrochemical complexes. While a lot of it is an inevitable necessity, a significant part of the same can be optimized through low level heat recovery. One of the ideas could be to heat the DM water in the process facilities to pick up the maximum heat with the intent of eliminating the air coolers. Most of this heat recovery would be in the regime, such that, DM Water is heated from 40 Deg C to 90-100 Deg C. The pre heated DM water could be utilized for generation of boiler feed water in the Plant ensuring that in the process facilities major air coolers are eliminated. Since considerable steam generation is anticipated within the process facilities as well as in the captive steam generation facilities, a good amount of heat which otherwise would have been rejected through air coolers or cooling water, or through a combination of air coolers and cooling water, would be optimally recovered in heating DM Water. This will provide tremendous capex benefits, rationalization of the opex and help in bringing all-round energy benefits to the Owner. Since the Complexes are becoming larger and larger, the benefit of this optimization can be enhanced and perhaps, air coolers to a large extent can be eliminated from the process design facilities. The hot water can be used to serve re-boiling requirements as well. This is capex and schedule friendly.  

6.    Based on integrated saturated and un-saturated gas plants, possibility of a common fuel gas treatment system for the high pressure fuel gases, system may be considered in the complex. This is particularly relevant when high pressure fuel gas is to be treated and integrated with down-stream complexes. For instance, the off-gases from FCC and DCU can be combined for treatment in a common fuel gas system and routed to an Olefin Complex for recovery of the valuables such as Ethylene, Recycle Ethane and Recycle propane.

7.    The complexes are generally becoming enormous in size with individual unit sizes also touching limits of design. This, apart from challenges, for process and mechanical engineering also brings about challenges in terms of flare loads. Since the flare loads are extremely large, it would be advisable to segregate the flares into high pressure and low pressure, such that the load can be divided, and integrated at the terminal end at offsite flare knock out drum. This enables reduction of line sizes and consequently, reduction in structural works, construction effort and manufacturing constraints linked with extremely large diameter piping.

8.    Since Cracking ratios in complexes are on the increase the cracked diesel in the feed, DHDT is also on the rise. Facilities, such as DCU, FCC and Ebullated bed Hydrocracking all generate diesel streams, which have a high cracked component. The percentage of cracked component in the Feed to diesel Hydrotreater is always significant. In case the total diesel component is less than 30% it would be worthwhile to consider Packinox Exchanger in place of multiple shell and tube heat exchangers in the high pressure loop of DHDT. This reduces the number of pieces of equipment in the plant and hence the pressure drop in the recycle loop also reduces significantly, providing thereby, huge opex advantages and saving in compression power.  The technology to utilize Packinox exchanger in a high pressure DHDT circuit, however, has only one licensor and consequently, therefore, this aspect may have to be carefully analysed before a decision is taken.

9.    With Euro-VI and BS-VI and higher specifications becoming the norm, the pressure level in the DHDT are on the rise. Also final diesel quality which is required is very stringent to ensure sulphur level less than 10 ppm. Typically, Hydrocrackers, yield diesel with quality less than 10 ppm as well. In case the refinery configuration envisages Hydrocracker, possibility of integrating the Hydrocracker and the Diesel Hydrotreater in a common process unit with a common diesel product specification can be explored. This will minimize the number of pieces of equipment, lead to cost savings, and above all, will bring significant opex benefit to the Owner. Also in many cases cracking catalyst is also being provided in DHDT reactors, to minimise diesel and maximise Naphtha. These units can be integrated in a common hydrocracker loop.

10. All process facilities in the complex, which provide an opportunity of repeating the process design in case the licensors are common. This must be explored. This provides huge schedule advantages for the benefit of the Owner. Between the Owner and Consultant, an agreement to this effect should always be explored prior to the initiation of the design, such that advantages of repeat Engineering are fully exploited.

11.  In case the objective function of the integrated complex, which is clubbed with Olefin Complex is to maximise petrochemical produce, ideally the configuration would be supported by a petro FCC. The off-gases from the FCC bear a lot of ethylene which can, after appropriate treatment be integrated with the Olefin Complex. This is tremendous horizontal integration linked with an integrated complex.  In case the refinery is equipped with a Once Through Hydrocracker, a good comparison must be made between the VGO Hydrotreater or Once Through Hydrocracker and feed to FCC and Olefin Complex. Though, invariably, the VGO Hydrotreater would possibly emerge as a favoured option, in case the refinery capacity is very high, there could be a case of a VGO Hydrotreater coupled with FCC and Once Through Hydrocracker, supporting the un-processed Hydrotreated material from HCU to be integrated in the Olefin Complex.

12. With the enhanced reliability of power grids in the country, it is worthwhile, to enhance the possibility of grid integration to mega integrated complexes. This will enable Elimination of Captive Power Plants from the complexes and have them replaced only with steam generation facilities. This would imply that, gas turbine etc from the integrated complexes, would get eliminated and power generation could be limited only to incidental levels. A good ratio could be 40% power to be produced within the complex premises on site and balance 60% to be sourced from the grid. The steam generation in the complex could be through utilization of pet coke pitch in CFBC facilities, such that most of the refinery fuels are actually utilized to enhance the distillates. Such provisions would minimize the capex tremendously, rationalize the opex enormously and bring about plot space benefits, making the complex extremely environmental friendly. The revenue from such complexes would enhance tremendously, as the fuels required in the CPP will find way into the distillate pools.

13. Most of the large complexes driven by refineries are under tremendous pressure to adhere to product specifications. This implies enhanced requirements of hydrogen is to be generated on plot. Typically, light naphtha is utilized to generate hydrogen, as gas is not available in India. However, now with the enhanced prospective/LNG facility creation the gradual enhancement for optimization in terms of gas integration to refineries is becoming the norm. Since the gas integration to the refinery not only, reduces the total Opex on account of differential price between the gas and naphtha, it reduces the carbon foot print also and releases enormous quantity of naphtha, which can be utilized to enhance the distillate pools or be routed to an Olefin complex for augmentation of petrochemical production. As a policy, Government must encourage the integration of gas to refineries, as it would improve its economy and energy efficiency, release tremendous amount of liquid distillates and enrich the petrochemical feed stock diet, or enable enhanced distillate produce from the Refinery. It could help in reduction of crude import therefore, even while the gas import increases.

14. The crude and vacuum distillation units of every refinery is a major energy consumer. The fact that the entire throughput has to be processed in this facility implies that energy optimization has to be a key consideration. One of the good ways to look into this integration would be to utilize vertical shell and tube exchanger in place of horizontal exchangers for the crude column overhead system. Also enhanced velocity of fluids in the Heat Exchangers to optimize the area of the Exchangers can be a good consideration. A pre fractionator column for large capacity units must be considered for an optimal design.

15. The Crude and Vacuum Units could be hot integrated as well, for a higher degree of heat recovery. 

16.  Depending upon the quality of crude to be processed, a key consideration to be weighed carefully in the design, would be to consider either an extremely low pressure crude column or maximise distillates recovery from the same or considering a low pressure crude column operating between 1.5 to 2 Kg/cm2g pressure levels and allowing a lot of diesel to slip in the RCO for higher levels of recovery in the vacuum column. A discussion to this effect should be carried out upfront, as it is a critical product recovery and energy optimization measure.

17. Helical Exchangers could be maximized in the Unit. Also the vacuum generating system could be a combination of vacuum pump and steam jet ejectors.

18. For all services wherein, the distillation has to be carried between fluids with relatively close boiling points, super fractionation techniques may be considered. For instance, MD Trays, may be considered in propylene fractionators etc. This enables reduction of shell weight and in several cases avoids splitting of a single column into two.

19. Heat Pump considerations are extremely relevant and must be outlined as a complex consideration. All areas were heat pump is to be considered must be identified early. Utilization of feed pump reducing cooling water requirements, reduces the weights of major columns, simplifies the erection of equipment though diameters of the column are likely to be enhanced. Ethylene and Propylene towers in Olefin Complex are potential cases to utilize heat pump to similar heat pump possibly can be considered in a petro FCC, as well, in case a good outlet for hot water recovery as part of low level heat recovery in the process unit can be identified.

20. Preference for usage of double walled columns must be given, in case very pure products from a single column are envisaged. Huge energy benefit can result out of this integration.

Pre-Investment Initiatives

One of the most critical decisions during the conceptual stages of a project is with respect to the provisions and the future expansions/upgradation of the project. Experience reveals that a water tight compartment approach is extremely deleterious. On a number of occasions, the Feasibility Report and capex considerations influence critical decisions. However, at every stage of the project, including feasibility stage, the possibilities of an ultimate capacity for a particular process unit, is an important consideration which must be borne in mind. This is particularly relevant for the hydro processing units, where it is extremely desirable, that the high pressure loop of the facility should always be designed for the ultimate capacity. Revamp in these areas is not only difficult, but extremely challenging and schedule unfriendly. Consequently, pre investment decision with respect to necessary hardware to be implemented in the initial stages itself and provisions specifically made for add-ons, must be clearly brought out. This is extremely vital. The following considerations must be kept in mind:

1.    For all land locked facilities design of the hydro processing equipment must be attempted to be designed the terminal capacity. This implies the reactor size, provision for future catalyst addition, design of the heat exchanger train with possible addition of a future high pressure heat exchanger set, margin in the recycle gas compressor and charge pump, and the sizing of the HP piping must be specifically addressed. Roughly 20-25 margin should be provided right from the feasibility stage for the hydro processing HP Equipment, which are extremely difficult to revamp later.

2.    On the low pressure section, the revamp is not an issue and adjustments can be made appropriately as and the updation is to be addressed.

3.    Similarly, all major towers must be addressed for the ultimate capacity and the sizing of the piping around the same must be additionally provided with 20-25% margin. Only the internals, perhaps can be changed as and when the revamp is required, to achieve the ultimate capacity.

4.    Critical equipment, such as compressors, extruders, coke drums, reactor, regenerator, vessels and cold box in the refinery/Olefin segment must be pre-invested for future capacity. It is very difficult to revamp these equipment for achieving the ultimate capacity. Invariably, if these equipment are not pre invested, it is very difficult to achieve the ultimate capacity of the plant without significant investment. Similarly, all critical piping, for instance, transfer lines, overhead piping sizes, must be pre invested with additional margins for reasons similar to the one cited above.

5.    As mentioned in the previous section, possibilities of retaining the sizes of Equipment and piping of previously implemented plants, if the technology licensor is same, must necessarily be explored. These are extremely vital for facilitating fast track implementation.

Basic Engineering

Key areas during basic engineering stages which can impact the complete approach towards implementation, must be foreseen and taken care of appropriately in the formative stages itself, particularly, during finalization of actual process design basis/basic engineering stages of Process Units. Items which get left out at this stage, are extremely hard to retrieve without very significant investments and schedule penalty. Some key areas which necessarily need to be looked into are as follows:

1.    Wherever possible, in the hydro processing block the reaction furnace and fractionation furnaces must be integrated for a common convection section, a common stack and a common energy conservations system. This will optimize plot space, enable capex saving and obviously bring OPEX benefits.

2.     Wherever possible, the side stripper and vessels connected with the columns should be stacked. For instance, strippers connected with the crude column and fractionation columns in gas plants of other Process Units, could be stacked for plot space savings and capex benefits etc. 

3.    Most of the large compressors are multi stage warranting to and fro suction piping connected with the compressors. Possibility of stacking the suction and discharge knock out drums connected with the compressors should be explored. This enables plot space optimization, rationalization of piping, minimization of capex and very significant reduction in the Delta P in the piping systems and hence enables saving in compression power. In a way, it enables an optimal process configuration.

4.    Wherever possible, state of the art technology must be utilized for maximum heat recovery. High flux heat exchanger, helix, core in kettle exchangers, must be utilized in the configuration to optimize the heat exchanger circuits for reduction of capex and minimization of OPEX.

5.    Within the Process facility condensing type turbines must be avoided. Back pressure turbines should be maximized and condensing turbines should be limited for very large and specific machines, such as Wet Gas Compressors in Delayed Coker Unit and FCC, MAB of FCC, Charge gas compressor in an Olefin Complex and multi stage refrigeration systems in Olefin Complexes. This is extremely important for rationalization of the cooling water requirements, minimizing the size of the headers and bringing implementation benefits for the Owner. Importantly, all the process services, where condensing type turbines are envisaged must be located near the periphery of the unit, such that, the connectivity to the same is minimized. This is extremely important for plant optimization.

6.    Special single vendor items, though extremely efficient, sometimes requires a close scrutiny.  For instance, usage of sundyne pumps need to be looked into carefully. Sometimes, the advantages of sundyne pumps are far outweighed by relatively inefficient centrifugal pumps on account of capex penalty.

7.    In large plants in the refineries, LPG must be preferably stored in cryogenic double walled tanks. Wherever the mounded storages required for LPG storages is more than six numbers, it is important to review the possibility of considering cryogenic storages. In case the refinery is equipped with a Petro FCC for maximization of propylene, the same may also be considered to be stored in cryogenic tanks. An integrated cryogenic storage system for LPG and Propylene more than justifies, the storage configuration. This leads to plot plan optimization, reduction in capex, though there could be a marginal increment in OPEX.

8.    An integrated Cold Box with maximum plate fin exchangers and intermediate vessels, housed inside the cold box, must be considered. Often for reasons of logistics, these are split, leading to enhanced structure, piping and insulation requirements, in the complex. The net piping workload increases dramatically, which has schedule implication. Plot space penalty and incremental OPEX is another issue as cryogenic heat leak is a major area to be controlled.  Enhanced Insulation too sometimes is also not good enough.

9.    Wherever possible, vertical reboilers and clean services must be maximized. 

10. Zero discharge is a critical requirement in all the refineries and petrochemical complexes or integrated complexes. One of the critical system which adversely affects this is the design of the caustic scrubber system in an Olefin Complex, of which, spent caustic often finds way, into the effluent treatment plant. This enhances the TDS of the ETP streams considerably. An effort should be made to minimise this. One of the ways that can possibly be considered is to utilize an Amine + Caustic Treatment System for cracked gas effluent in Olefin Complexes to replace caustic alone treatment systems. This optimizes the requirement considerably and reduces the net spent caustic treatment in the complex.   

11. In all the process units, which are large in size, SIS controls to minimize the flare load should be incorporated in the conceptual design stages itself. This should not be left as an after thought.

12. Normally, the licensors provide the optional metallurgy for silos, which invariably is SS or aluminium. It is important that this aspect must be closed in the FEED stages, such that these kind of options and variability is therefore, eliminated as part of FEED work.

13. Invariably in the Polymer Plants, the extruder is the longest path controlling the commissioning of the plant. To ensure concurrence and paralleling instead of waiting for Polymer production from the main process facility to provide feed to extruder, it is worthwhile, to always make an arrangement upfront of bring in polymer pallets from outside to facilitate commissioning of the extruder even prior to initiation of polymerization reaction in the process unit. This is a schedule optimization measure and extremely important to be considered upfront as it affects the overall schedule of implementation.

14. Wherever possible, plate exchanges may be foreseen for water-water services. This minimizes the plot space and capex.

15. The capacities of single train MEG units is on the increase. The controlling factor, however, is always the EO reactor weight and size could govern the number of reaction trains on account of its size. To rationalise, it is often more appropriate to consider duplex tubes for the MEG reactors. This reduces the system capex and definitely provides schedule advantages, which can lead to accumulated benefits. Single train, single reactor configuration of MEG Units, can therefore also be enhanced.

16. Fans for the boilers are always a large duty item. In a scenario of plant black out, often there are considerations where the steam production has to be sustained to ensure sustained and safe shut down of the Complex. It is worthwhile, to consider dual drives for fans with motor and a steam turbine equipped on either side of the fan rotor. This would facilitate operation of the plant during exigencies. The larger benefits are capex and certainly OPEX.

17. With the incremental sizes of complexes, the electrical requirements are also on the rise. Similarly, the single largest drive ratings are also on the rise. All these lead to challenges of optimization of the fault level considerations of the complexes. To obviate some of these concerns, it is worthwhile to consider, GIS switchgears in Captive Power Plant.

18. For minimization of cables and space optimization, XLPE cables in place of PVC may be considered for overall system optimization.

19. It is important that booster pumps in fire water systems are avoided in the process units. Sometimes, on account of large towers to cater to the water spray system, these are necessitated. The booster pumps, if provided, will alongside result in many associated classification related issues. It is advisable, that dedicated high duty pumping systems are provided in the fire water system pump house itself, to cater to the fire water requirements of water spray, around tall columns.

20. In India, liquids for cracking will always be a preferred feedstock for production of petrochemical intermediates. This warrants very large decoking requirement for the furnace coils.  It could always be a case to examine a dedicated air compressor vs dedicated compressor in the air system provided in the complex. Experience suggests, that an integrated system is a lot more useful in terms of optimization of capex and plot space and should be considered.

21. Every effort should be made to pinch hydrogen in the complex, as this is an expensive utility.

22. PMS for Unit in the complex must be standardized ensuring that the piping process are minimized. Upto 14” size #150 pipe the system should be replaced by 300 # rating across the complex.

23. Utility summaries must be updated well in advance, such that system configuration related inputs are provided adequately in the BEDP.

24. All data sheets of the rotating equipment must be completed to incorporate the API Plants, flushing systems and utility requirements.

Technology Sourcing  

1.    Wherever possible, the number of licensors must be minimized and in case no denial of opportunity can be ensured, the technologies should be basketed.

2.    The NIT should not be restricted to schedule-A process packages but should include an extended basic design scope to include thermal design of heat exchanger, air coolers, API data sheets of furnaces, control valves and safety valve sizing, results of which, should be incorporated in the P&ID.

3.    The Owner/Consultant/Licensors should finalize the dimensioned equipment layout of the plant during the PFD stage, such that hydraulics on various systems of the plant is performed on the dimensioned layout. This provides a very compact and complete P&ID, with possibilities of negligible changes during residual basic design basis.

4.    Areas warranting extended design to include detailed mechanical engineering must be decided upfront. The important candidates for these are reactor, regenerator system of FCC, CCR Reactor/Regenerator/ Furnace system.

5.    All polymer units reactor loop, coke drum system package, design of delayed coking furnaces and reformers, complete design of cracking furnaces including steam generation system and transfer line configuration.

Layout and Engineering

1.    All the piperacks, compressor houses, control room and substation building sizes must be standardized, for a wide variety of capacity of process units and considerations thereof.

2.    Similarly, a large number of technological structures for various process units based on experience must be standardized. This will provide flexibility of early finalization of layout, fast track engineering and huge amount of constructability related studies to be done upfront.

3.    For larger units, 12 M length of air coolers should be standardized. Also efforts should be made to be standardized the motors required for the air coolers of a specific rating or at best 2 or 3 sets of ratings across complex. This promotes interchangeability, rationalised sizes, promotes standardization and results in considerable schedule benefits.

4.    Electrical and Instrumentation cabling has an important schedule impacting consideration and should therefore, be located above ground on piperack in refineries and gas plants also, similar to petrochemical complexes. This is extremely schedule friendly, as it minimises underground works, facilitates maintenance and enables very compact layouts.

5.    All equipment and OWS systems thereof, must be segregated as contaminating and un-contaminating equipment in the plant and the areas demarcated accordingly. Even in the contaminated areas, highly contaminated and relatively lesser contaminated areas should be segregated. The contaminated and the non contaminated areas must be separated through curb walls etc, to differentiate between the OWS facilities. This shall enable segregation of OWS and CRWS systems, thereby rationalising the flow rates. Minimization of CRWS piping is a resultant objective of integration as a significant amount of non-contaminated areas of process units can be let out to open drains.

6.    Since most of the complexes are large with several process units, a central control room and distributed satellite rack room configuration could be followed. This shall also optimize overall cabling in the complex, as between the SRR and the control room, optical fibre network connectivity can be provided.

7.    Efforts have to be made to eliminate all Underground piping in offsites. Consequently, all the contaminated rain water, effluent collected within a process unit, must be allowed to be retained for a specified period of time (typically 15 minutes of maximum rainfall flow) beyond which, all the rain water can be allowed to be overflow to the storm water drain.  The catch pit for the same can be housed within the corridor of the Battery Limit and the hold up material from the catch pit could be transferred to ETP, through a pumping system. This will completely eliminate all underground piping, connected with CRWS system in offsites.

8.    Wherever possible, large cooling tower requirements must be assessed early and cooling towers segregated, such that, maximum capacity of a single cooling tower is restricted between 64,000 to 72,000 M3/hr. An eye should always be kept on the anticipated cooling water header size, as this could lead to implementation related issues.

9.    3 LPE coating can be considered for all large diameter Underground piping. For small diameter piping i.e. less than 8 to 10” even paint can be considered to eliminate all coating and wrapping.

10. The blow down from the cooling towers could be collected in a dedicated system to support a recycle plant to meet the DM water requirements of the complex. This will help in eliminating the DM Plant and all associated facilities from the complex, while the reject from the recycle plant could be restricted well below 2,100 TDS and the same could be utilized for horticulture purposes. 

11. All the hydro processing facilities must, to a large extent, be located in close proximity to minimize the hydrogen piping laying leads.

12. For all equipment layouts where capacities are large, central outlet of gravity piping from the units must be considered, to minimize the invert levels of U/G Piping.

13. Burial depths of all large diameter buried piping may be with 700 mm soil cover above the top of the pipe.

14.Whenever possible within plants, a segregation of high pressure and low pressure section, must be made in the layout. All critical equipment warranting heavy duty crane for erection must be located around the periphery of the unit. Similarly, all compressors equipped with condensing turbines, must necessarily be located near to the periphery of the plant to minimize cooling water piping.

15.In hydro processing blocks, combined compressor houses for reciprocating and centrifugal compressors may be foreseen in case a common hydrogen compression system is not foreseen in the complex. The common hydrogen compressor system be located in the hydrogen plant.

16. All hard stands and conceptual underground piping arrangement around the same must be planned upfront and indicated in the relevant equipment layouts and plot plans.

17. Layout have to be so arranged, such that, transfer line lengths are minimized, high pressure, high alloy and SS piping is also minimized and large diameter piping is kept to the bare minimum.

18. All air coolers connected with column overhead systems, may be located on the technological platforms, in place of  piperacks. Only the air coolers connected with pumped circuits may be located on piperack. This simplifies piperack configuration, eases maintenance, minimises structure and enhances approach.

19.  All major complexes should consider a tube extractor to rationalize the size of the technological platforms. The layout has to be construction friendly and effort has to be made that under no circumstances, anything is kept under HOLD while plant construction is in progress.

20. Invariably, the furnaces and energy conservation system must be arranged along one side of the plant, in favour of the wind direction. Wherever possible, a perpendicular transfer line piping, arrangement should be preferred, rather than side by side arrangement of columns and furnaces. This simplifies piping arrangement and enables smoother piping flexibility.

21.The safety valves in the unit must all be located on either side of the piperack. The flare header could be located centrally between the piperack or at one end depending on the overall piping system optimization.

22. Areas around the compressor houses should be kept open for maintenance purposes and equipment/piping should be arranged only towards the piperack side.

23. Wherever possible the inter-distance between the columns should be maximized, such that the footings at grade are reduced. This provides the more condensing arrangements to support piping around the piperack.

Structural

1.    All the bearing cooling water systems to be located Above Ground. This will minimize Underground piping and provide schedule benefits.

2.    All the funnel and CBD connectivity to be standardized. These can be carried out on a fast track basis upfront, with the intention that within 4 to 6 weeks all dimensioned equipment layouts being agreed with the licensors, the entire UG piping work should be completed. No inputs whatsoever are required from any quarter to finalise this activity.

3.    Provisions for monsoon protection systems, such as moveable graders located on piperacks must be conceived early, for securing sustained construction activity and schedule benefits around areas below racks.

4.    Wide flange sections must be maximized and all built up girders, star columns, must be avoided in design to reduce construction activities at site.

5.    For critical long span building sections, pre-stressed design to be maximized. For example, control room buildings, cooling tower and sump basin, polymer buildings, extruder buildings etc.

6.    For very high rise structures, composite construction must be conceived.

7.    For large units all piperacks to be of composite construction only.

8.    Usage of spiral welded piping for underground works may be maximized as the technology has sufficiently matured for supply of high quality piping.

9.    Only bolted structure designs to be provided.

10. Wherever possible for large unit consider piling. Even for units, where the bearing strength of the soil is good, for very tall and large pieces of equipment, piling must be preferred. Piling must be encouraged in cryogenic tank storage foundations, tall columns, below furnaces, large compressors, reactors etc.

11. For units where number of tall columns with sandwiched equipment in between the columns is foreseen, piling must be considered. For instance large Olefin Complexes, FCC, DCU etc.

12. Based on practical experience, segregation between high pressure and low pressure process units must be evolved. Factors must be decided to upgrade the schedule of rates which are evolved in conceptual stages of the project for tendering purposes. For all low pressure units, a good factor to modify the RCC and structural steel quantities is 25%. For high pressure units, this may be restricted to 10%.

13. All pavements to be of dual layer configuration. Pre-cast slabs which are not very high load supporting members may be considered.

14.Steel works may be maximised with predominance of bolted design configuration for fast track implementation.

Equipment

1.    Anchor bolts for all tall columns, medium size columns and equipment and smaller equipment should be rationalized, variety should be reduced and standardization should the prime consideration. This will bring schedule benefits.

2.    For major equipment in every unit, before finalization of MRs, the thickness of the plates, tube sheets, diameter of exchangers, lengths of exchangers etc must be standardized. This promotes economies of scale, minimises capex and enhances schedule adherence.

3.    The cleat standards to support platforms must be evolved, such that, the number of cleats in platforms are minimized.

4.    All items where the design and dimensions of the equipment are influenced by internals, for instance, filters, coalescers, the size of the vessel and outer dimensions, must all be frozen prior to placement of Purchase Oder. Bidder should be made to submit the dimensioned drawings for the shells, with the proviso that no change in the same will be permitted post award. This is essential for finalization of layout without HOLDS and fast track engineering.

5.    All the inputs for pumps to finalise the U/G connect, piping orientation, cables for motors and orientation thereof, instrumentation, must be finalized in Material Requisitions itself. No need of interface post award with vendors on these issues. A very high degree of standardization must be ensured.

6.    Lubricated machines in the hydrogen services must be preferred in the hydro processing plants, if need be, the catalyst compatibility with respect to lube oil carry over in the recycle routes must be interfaced with licensor. This simplifies machine procurement, reduces capex and enhances schedule adherence.

7.    In general, for all rotating equipment, settle out pressures must be stipulated in the process stage itself, such that machine procurement and auxiliary system definition becomes easier, for schedule and capex control.

8.    Supplementary items in the process plants, such as condensate pots, flare knock out drums, blow down vessels and pumps etc, must be standardized to the extent possible. This enables optimization, schedule adherence and minimization of capex.

9.    Provision for hydro com system must be encouraged to be used for large reciprocating complexes and foreseen in the early stages of the project. This has the potential of providing significant opex benefits to the Owners.

10. Wherever possible, swaged columns and knuckles in heads, must be avoided. These are highly schedule unfriendly. Instead of knuckle arrangements, hemi spherical heads must be preferred.

11.  As the sizes of the plants are on the increase, the bundle weight of the exchangers is bound to increase. For facilitating maintenance, it is worthwhile to consider rail + roller arrangement inside the shell for pulling out tube bundles. This will facilitate maintenance and reduces down time.

12. Energy conservation in process units is extremely important. Consequently, wherever possible, provisions for PRT, power expanders must be incorporated in the systems. Potential candidates for utilization of PRT are all major charge pumps, high pressure amine pumps in the hydro processing blocks and power expanders in FCC.

13. Inverted kettle designs as a substitute to Armstrong vaporizer can be a strong value add in various refineries and petrochemical in services, where 100% vaporization is envisaged. This should be closely examined.

14. Magnetic bearings in services warranting high speed in the machines may be explored for reducing the down time, reducing external sealing and flushing requirements and enhancing reliability and life of machines.

Piping

1.    Rationalise PMS by minimisation of classes, standardization of corrosion allowances and elimination of 150 # material upto a size of 14”. This shall be schedule effective and marginally cost intensive.

2.    Gradually, all engineering functions must switch over to smart systems from smart P&IDS to smart suite. Engineering must be optimized for schedule gains.

3.    Large sizes of process units are on the rise, usage of triple eccentric butter fly valves must be encouraged. This reduces the system capex, optimize the design and in several cases also rationalise the plot space.

4.    As the plants grow bigger and complex, it is important that pipe spools are encouraged to be fabricated at vendor’s works. All Alloy Steel, high pressure, steam circuits and piping above 8” should be spooled at the vendor’s works, such that implementation quality and speed is improved for all process plants.

5.    D/T ratios for large diameter piping must be carefully reviewed and stipulations which lead to conservatism in design must be avoided.

6.    Wherever possible, usage of cladded materials must be avoided as these are difficult to procure. This will enable schedule adherence and many cases system and capex optimization.

7.    Overhead piping connected with large columns should preferably be welded instead of a flanged connection. This will facilitate maintenance and construction schedules.

8.    Steam generation in the complexes should be foreseen at the highest level of SHP with P-91 MOC. This reduces the overall system cost pragmatically. Also it provides an opportunity for supporting of all SHP circuits.

9. SHP piping should be explored to be connected with the steam drives more than 20 MW, for an optimal machine/system configuration.

10. In general, all PSVs should be located on piperack only and location of PSVs on top of columns must be avoided to the extent possible. This simplifies the pipe design, minimises cleats on the column and reduces overall piping.

11. Possibility of pre-fabricated hook-ups to minimise instrument system configuration must be foreseen and planned upfront.

Conclusion

Culture of value engineering based approach to project implementation is a necessity. Apart from technical knowledge and a strong data base/experience, the will and passion to provide optimal solutions is a cultural engagement, which needs to be influenced amongst the team members. Consistent and regular monitoring of the systems must be encouraged to ensure that Value Engineering based design percolates down as a practice.

Value engineering is a sustained exercise and though based on experience and good engineering judgement, considerable amount of pre-emptive action can be taken up-fronts.  It still goes without saying that this is an exercise which needs to be consistently carried out for exploiting the best returns out of effort. Typically, the FEL-1 and FEL-2 stages i.e. initial conceptualization through DFR to FEED are critical stages in which the maximum benefits of value engineering can be realized. A good approach towards sustained value engineering culture would be to carry out option studies in the plant against specific issues and problems. Weighing of the options supported by techno economic analysis often leads to strong value engineering based solutions.

A directory of all the issues which lead to system optimization, plot savings, energy savings, reduction in capex, schedule friendliness are all areas which must be consistently tabulated for a project and taken forward. All issues pertaining to system integration through capex savings, minimisation of hardware, reduction of pieces of equipment are areas, which should always be accorded priority on a consistent basis.

Value engineering is a cultural issue as well. The issue needs to be turned towards optimization as a part of intrinsic philosophy. Companies consistent in value engineering, often bear a better chance of emerging as a more proficient and effective EPCs as well. Value Engineering is not a measure of compromising of quality or on standards but is an opportunity to provide an optimal solution within the provisions of the specifications and codal requirements. It is more an issue linked with practices and application engineering rather than theoretical support around a proposition.

Value engineering is a combined effort of deep knowledge around process design, engineering specifications, implementation nuances and operational dynamics. A good mix and balance between of these systems is what leads to a value engineered solutions to a problem!