Refining India 2022 Newspaper

refining india 2022

the actual unit operations (see Figure 3 ). Cases are stored in an associated data- base to allow historical trending and moni- toring of selected variables. Value Realisation Solutions like profit improvement and energy optimisation are taking advantage of all the technological advances already covered to turn what was originally a sin- gle engagement into a continuous process. Let us illustrate this through one aspect of our traditional refinery performance improvement programme: benchmarking, identification of gaps, and the opportunity roadmap for implementation. The value of identified opportunities is traditionally assessed using a base case operating sce- nario and pricing. Using a cloud platform, we can automate running the individual opportunity calculations against current conditions and pricing, letting you have a dynamic projection of value and making it easier to validate and select opportuni- ties for implementation. We can also make it easy to modify the list of opportunities on the roadmap, bringing in new ideas or operating modes for ongoing analysis. This makes much of the consulting analysis evergreen. Figure 4 shows some examples of the benefits obtained by different KBC clients from digital twin implementation.



Indicates recalibration of simulator and regeneration of LP model may be required






Data historian




C+ Gasoline/std ideal liquid volume ow - Measured C+ Gasoline/std ideal liquid volume ow - Simulator C+ Gasoline/std ideal liquid volume ow - LP

LCO/Mass ow - Measured

LCO/Mass ow - Simulator

LCO/Massow - LP

Figure 3 Example of actual vs LP vs simulator trends

Summary  Cloud-based architectures provide flexible storage, workflow, and compute methods, which allow for more flexible/ changeable integration and automation  Assembly of information in data lakes allows for insight from big data analysis benefiting from one source of the truth  Maturity of AI engines allows us to use AI for a wide range of use cases, such as early identification of potential faults, to improve data quality during data nor- malisation, and to use ML to supplement first-principle models that drive much of planning and scheduling.

Plan vs actual

Mass balance (VM-PA)

KPI dashboards for Perf Eval


1-5 c/bbl

Actual vs benchmarks

Reconciled data

Model assurance

Reliable models

Model representing Plant Operation forms foundation

Better plant LP Better backcasting Opp identication Better crude selection Better crude selection

Planning and scheduling

Closure between scheduler and LP

3-5 c/bbl


Quicker real time optimisation post scheduler

1-3 c/bbl

Constraint Mgmt

Giveaway reduction Catalyst management Cold eyes review Real time optimisation


5-30 c/bbl

DTs for owsheet

BT tracking

Furnace eciency

Compressor eciency

Energy demand

1-4 c/bbl

Emissions monitoring

Cold eyes review

Corrosion monitoring Fouling monitoring Integrity operating windows

Rotating machinery

Asset performance and integrity

3-10 c/bbl

Corrosion minimisation


Time to focus on other value added activities



Figure 4 Examples of expected benefits of digital twins

Recovery of ammonia from sour gases and conversion to valuable products

Saptarshi Paul, Balaji Lakavath, V Kamesh JayantitI Engineers India Ltd

Sour gases generated from a two-stage sour water stripping unit (SWSU) comprise mainly two types of waste stream: an H₂S- rich stream and an NH₃-rich stream (H₂S lean). Conventionally, the H₂S-rich stream is processed in the Claus section of a sul- phur recovery unit (SRU) to recover elemen- tal sulphur. However, treating the NH₃-rich stream for the destruction of NH₃ has two routes, one of which is co-processing with the H₂S-rich stream in the main burner of the SRU, which often causes severe opera- tional issues such as corrosion and choking. The second is processing through a reduc- tion furnace/incinerator (i.e. Claus sec- tion bypass), which is associated with high Capex and occasional high NOx generation (environmental issues). Recent trends indicate that ammo- nia demand in India is increasing every year, whereas historical data recorded the destruction of ~41,891 MTPA of NH₃ through the aforementioned routes in Indian refineries. Further, the increasing trend of bio-refining also needs an aqueous ammonia solution (20-30 wt%) for pH con- trol of the hydrolysis reactor. Apart from the production of urea, various other appli- cations of anhydrous ammonia include the manufacture of nitric acid, liquor ammonia, and the manufacture of explosives. To overcome the challenges of treating

an NH₃-rich waste stream and convert the same into a revenue-generating stream (waste to valuable product), EIL has devel- oped an ammonia recovery process (Indian Patent no. 350771) to recover ammonia from NH₃-rich sour gases and convert it into valuable products such as anhydrous NH₃ or aqueous NH₃.

Utilities: DM water, cooling water, power, caustic solution

Ammonia recovery unit

NH rich sour gas

Product aqueous ammonia or anhydrous ammonia

2-stage SWSU

Stripped sour water

HS rich gas to SRU

2nd stage stripper

Renery sour water

Sour water

Spent caustic to ETP

the increasing trend of bio- refining needs an aqueous ammonia

1st stage stripper


Figure 1 Schematic representation of ammonia recovery from refinery sour gas. A techno-commercial proposal for the ammonia recovery process has been submitted to an Indian refinery and is progressing towards implementation

A brief schematic of the process is pre- sented in Figure 1 . The NH₃-rich sour gas and stripped sour water from the two- stage SWSU are the feed streams for the ammonia recovery process. H₂S content in the feed gas is minimised in two steps: water wash and caustic wash. The gas is suitably pressurised and cooled based on downstream requirements, and it can then solution for pH control of the hydrolysis reactor

be routed as product or further processed for the preparation of aqueous ammonia based on client requirements. The overall recovery of ammonia is >99%, while H₂S concentration in the product is <5 ppmw. The sour water generated from the process is routed to the SWSU and can be accom- modated within the design margin of the SWSU or with minor hardware changes, if necessary. Salient features and advantages of the ammonia recovery process are: • Process eliminates operational issues related to ammonia-processing in the SRU and converts it into valuable product

• Process does not need any special chem- icals/catalysts, and utilities required are already available in the refinery • Acid gas processing capacity in the SRU can be increased • Savings in the SRU can be achieved in terms of reduction in fuel gas consumption in the incinerator and power consumption for air blowers • Impact on upstream two-stage SWSU can be accommodated within design mar- gins or through minor hardware changes, if necessary.



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