PROCESS AND COMPOSITION FOR MARINE FUEL

Abstract

A system and a method for producing a marine fuel are provided. An exemplary method includes processing a crude oil stream to remove at least a portion of metal contaminants to form a demetallized oil, processing the demetallized oil to remove at least a portion of sulfur contaminants to form a desulfurized oil, and stabilizing the desulfurized oil by removing light hydrocarbons to form the marine fuel.

Description

TECHNICAL FIELD

This disclosure relates to methods of producing marine fuel from a synthetic crude feed stream.

BACKGROUND

Recent treaties have placed restrictions on the sulfur content that can be present in bunker oils used as marine fuels. Further, environmental concerns have indicated the importance of low sulfur fuels for turbines, furnaces, boilers, and the like. Currently, compliant marine fuels must meet the International Maritime Organization (IMO) 2020 regulation that limits sulfur and fuel oil to a maximum of 0.50%, with a viscosity ranging between 30 centistokes (CST) and 380 CST at 50° C.

SUMMARY

An embodiment described herein provides a method for producing a marine fuel. The method includes processing a crude oil stream to remove at least a portion of metal contaminants to form a demetallized oil, processing the demetallized oil to remove at least a portion of sulfur contaminants to form a desulfurized oil, and stabilizing the desulfurized oil by removing light hydrocarbons to form the marine fuel.

Another embodiment described herein provides a system for producing a marine fuel from crude oil. The system includes a demetallization system, a desulfurization system, and a stabilization system to form the marine fuel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block flow drawing of a system for producing a marine fuel.

FIG. 2 is a block flow diagram of another system for producing a marine fuel.

FIG. 3 is a simplified process flow diagram of the system of FIG. 1.

FIG. 4 is a simplified process flow diagram of the system showing both the HDM reactor system and the HDS reactor system in the opposite cycle.

FIG. 5 is a simplified process flow diagram of a stabilizer that is used in various embodiments.

FIG. 6 is a simplified process flow diagram of another stabilizer that is used in various embodiments.

FIG. 7 is a process flow diagram of a method for generating a marine fuel from a crude oil feedstock.

DETAILED DESCRIPTION

Techniques are provided herein for generating marine fuels, low sulfur turbine fuels, or furnace fuels, and the like, that are compliant with the IMO 2020 sulfur limit. Further, the marine fuels are IMO-compliant 0.5% bunker oils as defined by ISO 8217:2017 with a sulfur limit of 0.5% and viscosity ranging between 30 and 380 CST at 50° C.

in one embodiment, the techniques include generating a synthetic crude oil, or syn-crude, which has a sulfur of lower than about 0.5 wt. %, and then processing the syn-crude in a stabilizer to lower the content of volatile compounds, providing a hydrocarbon mixture that meets the IMO 2020 specification for marine fuels. The techniques are not limited to generating a syn-crude but may use another separation process for lowering the sulfur and metals content of a crude oil stream.

The stabilizer is a partial distillation column or splitter disposed after most of the sulfur compounds and metal compounds are removed. The stabilizer separates the syn-crude into two components, a light fraction, and a heavy fraction, which meets the minimum flash point specifications, which is 60° C. for all grades of marine fuel. The heavy fraction can be used as the marine fuel or as a fuel for other processes. Additional hydrocarbon blending stocks can also be added to the heavy fraction to meet the specifications of the marine fuel while decreasing quality giveaway, for example, adding in a higher sulfur content oil to bring the total sulfur content closer to the specification.

FIG. 1 is a block flow drawing of a system 100 for producing a marine fuel. As shown in FIG. 1, a feed stream 102 of a sour crude oil goes through an HDM reactor system 104 and an HDS reactor system 106 to produce a synthetic crude (syn-crude) stream 108, which is then sent to a stabilizer 110 to produce a product stream 112 that comprises a marine fuel that is compliant with IMO 2020 specification. The stabilizer 110 also produces a light fraction stream 114. The conditions used in the reactor systems 104 and 106 can be adjusted based on the properties of the feed stream 102 so that the marine fuel in the product stream 112 meets the IMO 2020 specification, and other fuel specifications. Similarly, the separation point of the light fractions in the stabilizer 110 is done to the extent that the product stream 112 meets the specifications for the marine fuel.

The light fraction stream 114, which includes high volatility components such as C₅s or less, may be recycled back to the HDM reactor system 104. In some embodiments, the light fraction stream 114 is provided as a separate product.

FIG. 2 is a block flow diagram of another system 200 for producing a marine fuel. Like numbered items are as described with respect to FIG. 1. In this configuration, the syn-crude stream 108 from the HDS reactor system 106 is sent to the stabilizer 110 and a hydrocarbon blending stock 202 is also added to the stabilizer 110 to produce the product stream 112, which is compliant with the IMO 2020 specification. In some embodiments, the hydrocarbon blending stock 202 is a 210° C. fraction of the sour crude oil.

FIG. 3 is a simplified process flow diagram of the system 100 of FIG. 1. The feed stream 102 is fed to an HDM reactor system 104. In the HDM reactor system 104, the feed stream 102 is fed to an HDM reactor A 302, acting as a primary reactor, via feed valve A 304. Feed valve A 304 is in an open position during this cycle, while feed valve B 306 is in a closed position thereby directing the feed stream 102 into the HDM reactor A 302. In the HDM reactor A 302, hydrodemetallization occurs in the presence of a catalyst to create a first treated stream 308. The first treated stream 308 flows through first treated stream valve A 310 to create treated stream 312. First treated stream valve B 314 is in the closed position. Treated stream 312 is fed into an HDM reactor B 316, acting as a secondary reactor, through second treated stream valve A 318, while second treated stream valve B 320 is closed. The HDM reactor B 316 acts as a lag reactor at this point in the cycle.

A second treated stream 322 exits the HDM reactor B 316. The second treated stream 322 contains substantially reduced amounts of metal components such as vanadium, organic nickel and other organometallic compounds as compared to the feed stream 102.

As the first treated stream valve B 314 is closed, the second treated stream 322 is directed to exit flow valve A 324, which is open. Exit flow valve B 326 is in a closed position, thereby causing the second treated stream 322 to exit the HDM reactor system 104 as a hydrodesulfurization (HDS) feed stream 328.

The HDS feed stream 328 then enters the HDS reactor system 106. An HDS feed valve A 330 is open permitting the HDS feed stream 328 to flow into an HDS reactor A 332, as the primary reactor. During this cycle, HDS feed valve B 334 is closed. After treatment with catalyst in the HDS reactor A 332, a primary sweetened stream 336 exits the primary HDS reactor 332 and is directed through primary sweetened stream valve A 338, which is open, to create sweetened stream 340. Primary sweetened stream valve B 342 is closed. The sweetened stream 340 enters and HDS reactor B 344, acting as a secondary reactor, through secondary sweetened stream valve A 346. Secondary sweetened stream valve B 348 is closed during this cycle. The sweetened stream 340 undergoes further treatment in the presence of a catalyst in the HDS reactor B 344. A secondary sweetened stream 350 exits the HDS reactor B 344. With primary sweetened stream valve B 342 and HDS exit flow valve B 334 in a closed position, and HDS exit flow valve A 352 in an open position, the secondary sweetened stream 350 exits the HDS reactor system 106 as syn-crude stream 108 and is sent to the stabilizer 110.

The syn-crude stream 108 and the HDS feed stream 328 can be monitored to ensure demetallization and desulfurization specifications are met for the marine fuel. Four additional sample points [SP] can also be used to measure product quality following each of the respective reactors. Pressure drop in the HDM reactor A 302, the HDM reactor B 316, the HDS reactor A 332, and the HDS reactor B 344 can be monitored, for example using pressure transmitters coupled to a control system (not shown) located at the inlets and outlets of the reactors. The pressure drop can be used to monitor the state of catalyst within the respective reactor. Additionally, temperature transmitters can be used in the process, for example, at the inlets and outlets of the reactors. The temperature transmitters allow the measurement of the weighted average bed temperature (WABT) of each reactor. When the WABT approaches a predetermined limit, such as about 400° C., the flow through the process is cycled as described below in order to keep the WABT from exceeding the predetermined limit for a substantially constant product quality.

The cycling includes switching reactor order within the HDM reactor system 104, the HDS reactor system 106 or both such that the reactor that was previously in the secondary position subsequently is in the primary position. In order to accomplish this permutation, the valves designated as A are closed while valves designated as B are opened. For example, feed valve A 304, which was originally opened, would be subsequently closed, while feed valve B 306, which was originally closed would be subsequently opened. This is discussed further with respect to FIG. 4.

FIG. 4 is a simplified process flow diagram of the system 100 showing both the HDM reactor system 104 and the HDS reactor system 106 in the opposite cycle. Like numbered items are as described with respect to FIGS. 1 and 3. In this embodiment, all of the valves designated as A with respect to FIG. 3, are closed and all of the valves designated as B with respect to FIG. 3 are opened. Accordingly, the feed stream 102 flows into HDM reactor B 316, as the primary reactor, then the treated stream 312 flows into HDM reactor A 302, as the secondary reactor. Similarly, the HDS feed stream 328 flows into HDS reactor B 344, as the primary reactor, and the sweetened stream 340 flows into HDS reactor A 332, as the secondary reactor. It can be understood that any combination of the HDM reactor system 104 and the HDS reactor system 106 can be cycled between their respective reactors.

The hydrodemetallization and hydrodesulfurization systems are not limited to those shown in FIGS. 3 and 4. In some embodiments, a single system may contain both a hydrodemetallization reactor and a hydrodesulfurization reactor coupled in series. In other embodiments, a single reactor may include both hydrodemetallization zones and hydrodesulfurization zones, for example, including different catalysts and operated at different temperatures.

FIG. 5 is a simplified process flow diagram of a stabilizer 110 that is used in various embodiments. Like numbered items are as described with respect to FIG. 1. In the stabilizer 110, the syn-crude stream 108 is fed to the inlet of a column 502. The column 502 is generally a partial distillation column, for example, not having a reflux condenser or reflux stream injected into the upper portion of the column 502. However, in some embodiments, the column 502 may be a full distillation column. The light fraction stream 114 is separated from the syn-crude, exiting the column 502 from an outlet near or at the top.

A reboiler 504 is coupled to the column 502 to control the separation temperature between the light fraction stream 114 and the product stream 112. A bottom stream 506 is taken from the column 502 and fed to the reboiler 504. In the reboiler 504, a heat exchanger heats the bottom stream 506 by exchanging heat with a heating fluid, such as a hot steam stream 508. A cooled steam stream 510 exits the reboiler 504 and, for example, returns to a utilities plant (not shown). A heated stream 512 is then returned to the column 502.

A hot product stream 514 can be taken from the bottom of the column 502, or, as shown, can be taken from the reboiler 504. The hot product stream 514 is passed through a heat exchanger 516, to be cooled by exchanging heat with a coolant stream 518, such as a chilled water stream. After passing through the heat exchanger, a hot water stream 520 is returned to the utilities plant. The product stream 112 then exits the heat exchanger 516. In some embodiments, the product stream 112 is directly sold as the marine fuel.

The stabilizer 110 is not limited to a partial distillation column. Other separation systems, such as a full distillation system, a flash vessel, a cyclonic separation system, and the like, may be used in embodiments. Further, as described with respect to FIG. 2, a hydrocarbon blending stock 202 (FIG. 2) can be added to the syn-crude stream 108 prior to introduction into the column 502. The addition of the hydrocarbon blending stock 202 can be used to tune the final properties of the product stream 112. In some embodiments, side cuts or side draws can be added to the stabilizer column to adjust the composition of the marine fuel. The side draws can include a naphtha draw at the top or a distillate draw in the middle of the column.

FIG. 6 is a simplified process flow diagram of another stabilizer 110 that is used in various embodiments. Like numbered items are as described with described with respect to FIG. 5. The generation of other products may be useful, for example, depending on the need for marine fuel. In FIG. 6, the column 502 of the stabilizer 110 has stabilizer 110 has two side draws 602 and 606. These may be placed at particular temperature points in the column 502. The side draws 602 and 606 are fed to a secondary stripper column 608. The secondary stripper column 608 may be used to produce any number of other products, such as a naphtha stream 610 having a boiling point of about 90° C. to about 200° C. Other streams may also be produced, such as a diesel stream 612 having a boiling point of about 180° C. to about 360° C.

FIG. 7 is a process flow diagram of a method 700 for generating a marine fuel from a crude oil feedstock. The method 700 begins at block 702, when the crude oil is processed to remove at least a portion of metal contaminants forming a demetallized oil. This may be performed as described with respect to the Figures above by processing the crude oil feedstock in a hydrodemetallization reactor.

At block 704, the demetallized oil is processed to remove at least a portion of sulfur contaminants forming a desulfurized or syn-crude oil. As an example, using the two-step process described above that includes HDM and HDS sections, a typical syn-crude would have properties as listed in Table 1.

TABLE 1
properties of an example synthetic crude oil
Properties of Synthetic Crude A
	Crude Origin	Synthetic Crude A
	Density at 15° C.	g/ml	0.8732
	CCR	wt %	4.5
	Vanadium	wtppm	19.1
	Nickel	wtppm	7.4
	Sulfur	wt %	0.4400

Although the sulfur content of the example syn-crude is about 0.44 wt. %, which is less than the limit of 0.5 wt. % In the IMO 2020 specification, it would still require further processing to be converted into marine fuel. Specifically, the content of high volatility components would be above specification limits. For example, the fractionation, or cutpoint, can be between about 40° C. and about 150° C. At block 606, the light fraction is separated to form the marine fuel, or other types of fuel such as turbine fuel, furnace fuels, and the like.

EMBODIMENTS

An embodiment described herein provides a method for producing a marine fuel. The method includes processing a crude oil stream to remove at least a portion of metal contaminants to form a demetallized oil, processing the demetallized oil to remove at least a portion of sulfur contaminants to form a desulfurized oil, and stabilizing the desulfurized oil by removing light hydrocarbons to form the marine fuel.

In an embodiment, combinable with any other embodiment, the method includes processing the crude oil stream in a hydrodemetallization reactor to form the demetallized oil.

In an embodiment, combinable with any other embodiment, the method includes processing the demetallized oil in a hydrodesulfurization reactor to form the desulfurized oil.

In an embodiment, combinable with any other embodiment, the method includes performing a partial distillation to separate the light hydrocarbons from the desulfurized oil to form the marine fuel.

In an embodiment, combinable with any other embodiment, the method includes adding a hydrocarbon blending stock to an effluent from a stabilization column to form the marine fuel.

In an embodiment, combinable with any other embodiment, the method includes reacting the crude oil stream with a supercritical water stream to remove the portion of the metal contaminants.

In an embodiment, combinable with any other embodiment, the method includes reacting the crude oil stream with a supercritical water stream to remove the portion of the sulfur contaminants.

In an embodiment, combinable with any other embodiment, the method includes reacting the crude oil stream with an alkali material to remove the portion of the metal contaminants.

In an embodiment, combinable with any other embodiment, the method includes reacting the crude oil stream with an alkali material to remove the portion of the sulfur contaminants.

In an embodiment, combinable with any other embodiment, the method includes reducing the sulfur contaminants in the desulfurized oil to form the marine fuel including less than about 0.5 wt. % sulfur.

Another embodiment described herein provides a system for producing a marine fuel from crude oil. The system includes a demetallization system, a desulfurization system, and a stabilization system to form the marine fuel.

In an embodiment, combinable with any other embodiment, the demetallization system includes a hydrodemetallization reactor.

In an embodiment, combinable with any other embodiment, the system includes two hydrodemetallization reactors sequentially coupled.

In an embodiment, combinable with any other embodiment, the sequential coupling of the two hydrodemetallization reactors is reversible.

In an embodiment, combinable with any other embodiment, the desulfurization system includes a hydrodesulfurization reactor.

In an embodiment, combinable with any other embodiment, the system includes two hydrodesulfurization reactors sequentially coupled.

In an embodiment, combinable with any other embodiment, the sequential coupling of the two hydrodesulfurization reactors is reversible.

In an embodiment, combinable with any other embodiment, the demetallization system, the desulfurization system, or both, includes a supercritical water reactor.

In an embodiment, combinable with any other embodiment, the demetallization system, the desulfurization system, or both, includes an alkaline metal reactor.

In an embodiment, combinable with any other embodiment, the stabilization system includes a partial distillation tower.

In an embodiment, combinable with any other embodiment, the stabilization system includes a full distillation tower.

In an embodiment, combinable with any other embodiment, the stabilization system includes a flash vessel.

In an embodiment, combinable with any other embodiment, the marine fuel includes less than about 0.5 wt. % sulfur.

In an embodiment, combinable with any other embodiment, the demetallization system and the desulfurization system are combined into a single unit.

In an embodiment, combinable with any other embodiment, the stabilization system includes a secondary stripper coupled to a side draw from a stripper column.

In an embodiment, combinable with any other embodiment, the stabilization system includes a diesel stream from the secondary stripper column.

Other implementations are also within the scope of the following claims.

Claims

1. A method for producing a marine fuel, comprising: processing a crude oil stream to remove at least a portion of metal contaminants to form a demetallized oil;processing the demetallized oil to remove at least a portion of sulfur contaminants to form a desulfurized oil; andstabilizing the desulfurized oil by removing light hydrocarbons to form the marine fuel.

2. The method of claim 1, comprising processing the crude oil stream in a hydrodemetallization reactor to form the demetallized oil.

3. The method of claim 1, comprising processing the demetallized oil in a hydrodesulfurization reactor to form the desulfurized oil.

4. The method of claim 1, comprising performing a partial distillation to separate the light hydrocarbons from the desulfurized oil to form the marine fuel.

5. The method of claim 4, comprising adding a hydrocarbon blending stock to an effluent from a stabilization column to form the marine fuel.

6. The method of claim 1, comprising reacting the crude oil stream with a supercritical water stream to remove the portion of the metal contaminants.

7. The method of claim 1, comprising reacting the crude oil stream with a supercritical water stream to remove the portion of the sulfur contaminants.

8. The method of claim 1, comprising reacting the crude oil stream with an alkali material to remove the portion of the metal contaminants.

9. The method of claim 1, comprising reacting the crude oil stream with an alkali material to remove the portion of the sulfur contaminants.

10. The method of claim 1, comprising reducing the sulfur contaminants in the desulfurized oil to form the marine fuel comprising less than about 0.5 wt. % sulfur.

11. A system for producing a marine fuel from crude oil, comprising: a demetallization system;a desulfurization system; anda stabilization system to form the marine fuel.

12. The system of claim 11, wherein the demetallization system comprises a hydrodemetallization reactor.

13. The system of claim 12, comprising two hydrodemetallization reactors sequentially coupled.

14. The system of claim 13, wherein the sequential coupling of the two hydrodemetallization reactors is reversible.

15. The system of claim 11, wherein the desulfurization system comprises a hydrodesulfurization reactor.

16. The system of claim 15, comprising two hydrodesulfurization reactors sequentially coupled.

17. The system of claim 16, wherein the sequential coupling of the two hydrodesulfurization reactors is reversible.

18. The system of claim 11, wherein the demetallization system, the desulfurization system, or both, comprises a supercritical water reactor.

19. The system of claim 11, wherein the demetallization system, the desulfurization system, or both, comprises an alkaline metal reactor.

20. The system of claim 11, wherein the stabilization system comprises a partial distillation tower.

21. The system of claim 11, wherein the stabilization system comprises a full distillation tower.

22. The system of claim 11, wherein the stabilization system comprises a flash vessel.

23. The system of claim 11, where in the marine fuel comprises less than about 0.5 wt. % sulfur.

24. The system of claim 11, wherein the demetallization system and the desulfurization system are combined into a single unit.

25. The system of claim 11, comprising a secondary stripper coupled to a side draw from a stripper column.

26. The system of claim 25, comprising a diesel stream from the secondary stripper.