Lanzhou Petrochemical "molecular refining" to find the key to optimization

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Since December 2016, 1.2 million tons of diesel oil hydrogenation unit of Lanzhou Petrochemical Company has made every effort to complete the task of reducing inventory of catalytic diesel oil. In order to ensure the stable production and increase production of the unit under the condition of full catalytic diesel oil, the concept of "molecular refining" is introduced into the diesel oil hydrogenation combined workshop, and the three links of "process optimization, process monitoring and quality analysis" are well controlled, so as to deeply tap the operation potential of the unit. Up to now, Lanzhou Petrochemical has processed a total of 32000 tons of catalytic diesel oil in stock, and has digested 41.77% of the planned inventory of diesel oil. The effect of diesel oil inventory reduction is obvious.

Lanzhou Petrochemical Company's annual 1.2 million tons of diesel oil hydrogenation unit mainly processes catalytic diesel oil and straight run diesel oil. Under the condition of processing full catalytic diesel oil, it is necessary to not only raise the temperature to meet the reaction depth, ensure the product quality to meet the standards, but also control the reactor outlet temperature to prevent overtemperature, and prevent the oil from cracking to reduce the light oil yield. The conventional production technology scheme has been unable to achieve the reduction of diesel oil Purpose of terminal storage.

At the end of November 2016, the diesel inventory of Lanzhou Petrochemical Company was running at a high level, the upstream catalytic unit was running at a high load, and the production balance pressure of Lanzhou Petrochemical Company was increasing. The plant Department required the 1.2 million tons of diesel oil hydrogenation unit to process catalytic diesel oil in full working condition. After communication and discussion with the design unit and catalyst manufacturer, the concept of "molecular refining" was introduced into the workshop. Starting from the molecular reaction of the device medium, the process operation parameters were calculated again and the best control scheme was worked out. The plant has two reactors in total. Through practical calculation, the workshop proposes to "turn each reactor into three" and regard each bed layer of the reactor as an independent small reactor. The molecular reaction in each small reactor is studied in depth, the optimal combination of operation conditions is calculated, and the execution and control during operation are strengthened.

In view of the low material grade of the high and low pressure heat exchanger e-1102, the workshop strictly regulates the control range of various parameters, formulates the production control plan and accident emergency plan, effectively ensures the stable control of various parameters, safe and controlled overall operation, and the sulfur content of diesel oil meets the national V standard.

At the same time of digesting the inventory of catalytic diesel, the annual 3 million tons of diesel hydrotreating unit makes every effort to process straight run diesel and coking gasoline diesel, and tries to control the total diesel inventory in the irrigation area to be stable. The hydrogen production unit shall formulate standardized operation flow to ensure the stable supply of hydrogen according to the quantity. In the next step, the workshop will bring the key process parameters into the scope of the competition, realize the stable and even control of the reaction process through the refinement and materialization of management, and steadily reduce the inventory of catalytic diesel oil in the tank farm by 40 tons / hour.

Extended reading——

What is "molecular refining"? "Molecular refining" is to understand the oil processing process from the molecular level, accurately predict the product properties, optimize the process and processing flow, enhance the value of each molecule, and realize the production concept of "appropriate olefin, appropriate aromatics, appropriate oil, appropriate oil".