Refining - TOP-REF Project

Company: Petrogal Energía

Sector: Refining

Capacity: 220 kbpd

OpEx: More then 40 M€/y

Energy Associated Cost: 60-70% of OpEx

Total Fuel Consuption: 500 kton NGE/y

Fuel Used in Steam Generation: ∼35%

Fuel Used in Heating: ∼65%

Steam flows

24 bar (intermediate pressure-IP): Largely produced in the electricity-generating steam turbines, is routed to the process units for several purposes (stripping, turbines, heat-exchange and steam ejectors). High pressure steam (80 bar) can also be also “letdown” into the 24 bar steam header to maintain at the set point value. Moreover, the IP steam is also produced in the process units.

10.5 bar (medium pressure-MP): Produced in 24 ” 10.5 bar turbines and “letdown” valves, is used in utility stations around de refinery and some specific applications for which low-pressure steam does not have enough temperature. Each Production Process Plant manages its own MP steam.

3.5 bar (low pressure-LP): Produced in steam turbines (electricity-generating and others), “letdown” valves and process units.

Boiled water flow

The water used to produce steam requires special features to prevent corrosion and accumulation of scale and sludge in tubes, exchangers and drums. Consequently, the make-up water added to replace losses (stripping steam, steam ejectors, etc.) has to be demineralized/deionized and deaerated water. Demineralized is also used as an utility in the process units. The recovered condensate is also routed back to the BFW circuit.

Challenges and expected improvements: as part of the C.I.P. Climate Check a systematic screening of energy efficiency improvements has been recently performed and all feasible improvement measures are currently being implemented.

Other resources flow

Nitrogen (7 bar): The nitrogen is supplied by an external company.
Plant Air (7 bar): Compressed air produced from ambient air by centrifugal compression.
Instrument Air (7 bar): Plant air which after drying is used for plant pneumatic instruments.
Cooling Water (15-25ºC): For trim coolers, produced from the cooling water return by evaporation on cooling towers (electric driven fans).
Raw Water: Used essentially in the utility stations.
Fuel: FO distribution is also managed by the Utilities Plant.

Industrial comments and concerns

Fuel, electricity, steam and boiler feed water (condensate) systems will be analysed during this project; the remaining flows are much less important from an energy intensity point of view, therefore just a brief analysis will be done to assure the optimization of the whole process

The final deliverable of the project, besides the performance indicators and modelling, will be a monitoring and control software, which follows all the relevant aspects about the resource flows use, namely:

On-line operating parameters (electric currents, temperatures, pressures, etc.).
On-line performance indicators (turbine efficiency, overall electricity generation efficiency, etc.).
Reconciled electricity, steam and boiler feed water balances (material and energy).
On-line energy flux diagrams.
Fuel, Electricity, steam and boiler feed water losses.

Quality challenges

Energy efficiency optimization should be carried out without introducing changes in the quality of the products of the utilities plant, in this case steam ( IP, MP, LP) and electricity. The influence of operating parameters (pressure, temperature) on equipment performance (boilers, turbines) can be considered within the specified range.

Safety challenges

Safety is always a number one priority, all the energy efficiency optimization shall be carried out taking into account the strict safety regulation of the refinery