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Portfolio №1. Maximising diesel recovery from the VGO (hydrotreating of vacuum gas oil).

Although the column have 10 trays between the flash zone and the diesel product draw, the vacuum gas oil contains 9% diesel. The key cause is the tray dumping due to excessive tower diameter (The flooding factor < 20 %). It is necessary to block the part of the tray deck to increase the FF and to maximise diesel recovery.

Figure 1 – main fractionating column of VGO unit.

Table 1 - Results

Product Name Production capacity

tonne / hour Price

1000 * roubles / tonne Before After

Naphta 7,0 7,0 23,7 Diesel 28,0 43,0 27,0 VGO 325,0 310,0 18,8

TOTAL 360,0 360,0 -

FFmax = 16 %

FFmax = 19%

FFmax = 27%

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№2. Increasing benzin recovery from LVGO. FCC unit, main fractionating column. The LVGO contains 30% naphta. Raising the L/V ratio between the TOP and the LVGO draw (due to PA heat redistribution) and shifting the LVGO draw locations from № 10 to № 12 tray may increase the naphta recovery (+ 2 tonne / hour).

Figure 2 – main fractionating column of FCC unit.

Table 2 - Results

% vol.

ASTM D86, °С Benzin LVGO

Before After Before After 5 - - 150,2 164,9 10 - - 198,0 218,8 95 186,9 192,5 260,6 271,3 100 212,7 218,3 269,7 279,7

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№3. Reducing the sulfur content in the vacuum gas oil. VGO unit. The target is to diminish the sulfur content in VGO from 450 to 370 ppm. To do this we have to raise the inlet temperature before the reactor from 350 to ≈ 370 0C (figure 3). The total absorbed duty of the fired heater is 3,8 Gkal / hour, the working – 3,7 Gkal/ hour. Construction of a new furnace is a very expensive.

Figure 3 – Fired heater duty before and after Several engineering solutions achieve the same objective though the capital cost is much less than the new furnace (figure 4, 5, 6).

Figure 4 – Solution №1

After

Before

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Figure 5 – Solution №2

After

Before

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Figure 6 – Solution №3

Before

After

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№4. Atmospheric crude unit. The target is to maximise diesel recovery and to increase heat recovery. There are two solutions (figure 7).

Figure 7 – Solution №1 and №2 - increasing L/V ratio between the flas zone and the diesel product draw - increasing fractionation efficiency due to packing - Increasing the PA flowrate hence increasing the LMTD - the residue contains only 4% diesel.

№5. Increasing iso-butane recovery. - minimizing losses of propane (recovery is 95%) due to absorption - increasing iso-butane recovey due to replacing of iso-butane in C3-C4 for n-butane

Figure 8 – Solution

L/V ratio = const DT draw ≠ const stability

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№6. Improving the degree of fractionating. The degree of fractionating in the atmospheric column is inadequate. The key cause is the “shock” condensation due to excessive ΔT (~120 0С) between draw and return temperature of PA №1,2 and 3. Increasing the PA flowrate decreasing the ΔT (~60 0С) results in improving the degree of fractionating (figure 9).

Figure 9 – Comparative analysis

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№7. Optimization and adjustment of CDU-VDU. Moscow 2016. The complex analysis of the unit was performed. The aggregate result – figure 9. The increasing of heat recovery is about 35 Gcal/h (~ 139 000 000 Btu). “Нефть” – crude oil; “Нафта” – naphta; “Мазут” – residue; “Пар” – steam; “Гкал/ч” – Gcal/h.

Figure 10 – Before and after

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№8. Vacuum heater in conjunction with transfer line. Moscow 2016.

Before After Furnace outlet temperature, 0C 398 385

Hot skin temperature, 0C 590 535 Flow pass 6 4

Mass flow rate, kg/m2•sec 866 1350 ΔP transfer line, torr 250 100 ΔT transfer line, 0C 15 6

Maximum velocity > Critical velocity YES! NO

Figure 11 – Transfer line before (6 pass) and after (4 pass)

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№9. CDU-VDU Process control. Moscow 2016. The main principle: The Heat balance – primary; The material balance – secondary, i.e. L/V ratio = const and DT draw ≠ const.

Figure 12 – The proposed control technology