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Ozren Ocic Oil Refineries in the 21st CenturyOil phần 5

Sự khác biệt giữa tổng điện năng tiêu thụ và lưới xuất hiện trong trường hợp của MP và LP hơi do hơi nước thế hệ nội bộ trong nhà máy. Nội bộ MP hơi thế hệ của 135 000 t hoặc 404 TJ đáp ứng các yêu cầu quy trình. Một phần của hơi nước, tức là 115 000 tấn hoặc 344 TJ, được sử dụng cho các ổ đĩa máy bơm thông qua các tua-bin hơi nước và một phần khác của 20 000 t | 52 4 Instruments for Determining Energy and Processing Efficiency of an Oil Refinery 1 f 27.636 . 2 4.573 r 3 1.17 r 4 10.70 r 5 0.03 . 6 0.135 _ 1. FUEL GAS t y 2. FUEL OIL t y 3. COOLING WATER 1Ũ6 m7y 4. EL. POWER 106 kWh y 5. LP STEAM CONSUMPTION 106 t y 6. MP STEAM CONSUMPTION 106 t y 7. LP STEAM GENERATION IN HEAT EXCHANGER 106 t y 8. LP STEAM GENERATION FROM A BACK-PRESSURE TURBINE 106 t y 9. MP STEAM GENERATION 106 Vy 10. HEATING THE FEEDSTOCK BY MEANS OF PRODUCT HEAT Scheme 4 Energy flows of vacuum-residue visbreaking process For the purpose ofthis process block the energy-flow scheme is shown in Scheme 4 and Senky s diagram for the energy balance in Diagram 3. The values given for the energy consumption refer to the annual scope of processing being 973 085 t ofvacuum residue and for a specific slate of products. Diagram 3 Senky s diagram of energy flows of vacuum-residue visbreaking process in TJ y 4.3 Instruments for Determining Energy and Processing Efficiency of Vacuum-residue Visbreaking Unit 53 The difference between gross and net power consumption appears in the case of MP and LP steam due to internal steam generation in the plant. Internal MP steam generation of 135 0001 or 404 TJ meets the process requirements. Part of the steam i.e. 115 000 t or 344 TJ is used for the pump drive through steam turbines and the other part of 20 000 t or 60 TJ for other process purposes. 4.3.3 Determining the Steam Cost Price The procedure for determining the cost price of steam as a possible instrument for monitoring the energy efficiency needed by operative management is given in Tables 18 and 19. From Tab. 18 it can be seen that the cost price of MP steam generated in the vacuum-residue visbreaking unit is only 0.22 US t. The basic explanation for such a cost lies in the fact that on this particular plant the steam is obtained as a by-product utilizing the heat of the flue gases in the boiler and the heat of the products in the heat exchangers thus offsetting the