Process and reactor for upgrading heavy hydrocarbon oils

Abstract

A process using supercritical water to upgrade a heavy hydrocarbon feedstock into an upgraded hydrocarbon product or syncrude with highly desirable properties (low sulfur content, low metals content, lower density (higher API) lower viscosity, lower residuum content, etc.) is described. The process does not require external supply of hydrogen nor does it use externally supplied catalysts. A reactor design to carry out the process is also described,

Description

FIELD OF THE INVENTION[0001]The present invention relates to upgrading of hydrocarbons, especially heavy hydrocarbons such as whole heavy oil, bitumen, and the like using supercritical water.BACKGROUND OF THE INVENTION[0002]Oil produced from a significant number of oil reserves around the world is simply too heavy to flow under ambient conditions. This makes it challenging to bring remote, heavy oil resources closer to the markets. One typical example is the Hamaca field in Venezuela. In order to render such heavy oils flowable, one of the most common methods known in the art is to reduce the viscosity and density by mixing the heavy oil with a sufficient diluent. The diluent may be naphtha, or any other stream with a significantly higher API gravity (,i.e. much lower density) than the heavy oil.[0003]For a case such as Hamaca, diluted crude oil is sent from the production wellhead via pipeline to an upgrading facility. Two key operations occur at the upgrading facility: (1) the dil...

AI Technical Summary

Benefits of technology

[0025]The present invention relates to a process for upgrading hydrocarbons comprising: mixing hydrocarbons with a fluid comprising water that has been heated to a temperature higher than its critical temperature in a mixing zone under conditions that disfavor thermal cracking and formation of coke to form a mixture; passing the mixture to a reaction zone, reacting the mixture in the reaction zone having a substantially uniform temperature distribution and being configured to reduce the settling of solids within the reaction zone said reaction occurring under supercritical water conditions in the absence of externally added hydrogen for a residence time controlled within determined limits to allow upgrading reactions to occur; withdrawing a single-phase reaction product from the reaction zone; and separating the reaction product into gas, effluent water, and upgraded hydrocarbon phases.

Problems solved by technology

Oil produced from a significant number of oil reserves around the world is simply too heavy to flow under ambient conditions.

This makes it challenging to bring remote, heavy oil resources closer to the markets.

1. The infrastructure required for the handling, recovery, and recycle of diluent could be expensive, especially over long distances. Diluent availability is another potential issue.

2. Hydrogen-addition processes such as hydrotreating or hydrocracking require significant investments in capital and infrastructure.

3. Hydrogen-addition processes also have high operating costs, since hydrogen production costs are highly sensitive to natural gas prices. Some remote heavy oil reserves may not even have access to sufficient quantities of low-cost natural gas to support a hydrogen plant. These hydrogen-addition processes also generally require expensive catalysts and resource intensive catalyst handling techniques, including catalyst regeneration.

4. In some cases, the refineries and / or upgrading facilities that are located closest to the production site may have neither the capacity nor the facilities to accept the heavy oil.

5. Coking is often used at refineries or upgrading facilities. Significant amounts of by-product solid coke are rejected during the coking process, leading to lower liquid hydrocarbon yield. In addition, the liquid products from a coking plant often need further hydrotreating. Further, the volume of the product from the coking process is significantly less than the volume of the feed crude oil.

Although the above-mentioned patents disclosed and claimed various methods and processes for heavy oil upgrading using supercritical water, such as operating range of temperature and pressure, water to oil ratio, etc, none has disclosed the design of the reactor or design related process controls for heavy oil upgrading using supercritical water.

Although organic materials can be destroyed quickly through supercritical water oxidation, inorganic materials are insoluble in supercritical water.

For heavy oil upgrading, the feed is a mixture containing broad range of materials, and the reactions involved are much more complex.

Obviously, reactor design for selective reactions in a complex system is very different and much more challenging than that for non-selective total oxidation.(2) High concentration of feed.

Images