Hydroprocessing Of Biocomponent Feedstocks With Low Purity Hydrogen-Containing Streams

PATENT

Hydroprocessing Of Biocomponent Feedstocks With Low Purity Hydrogen-Containing Streams

Pub. No.: WO/2011/082142

International Application No.: PCT/US2010/062173

Publication Date:  07.07.2011

IPC:  C10G 3/00 (2006.01), C10G 45/02 (2006.01), C10G 45/58 (2006.01), C10L 1/02 (2006.01)

Applicants:

EXXONMOBIL RESEARCH AND ENGINEERING COMPANY [US/US]; 1545 Route 22 East P.o.box 900 Annandale, NJ 08801-0900 (US) Inventors:

HANKS, Patrick, L.; (US).
ELLIS, Edward, Stanley; (US)

Abstract:

A biocomponent feedstock can be hydroprocessed using a hydrogen-containing refinery as a source of hydrogen gas. A relatively low cost catalyst, such as a water gas shift catalyst and/or spent hydrotreating catalyst, can be used as a hydrogenation catalyst for the process. The hydroprocessing can allow for olefin saturation and/or deoxygenation of the biocomponent feed by using a relatively low value refinery stream, e.g., containing from about 20 mol% to about 60 mol% hydrogen.
FIELD

[0001] Systems and processes are provided for hydrotreatment of biocomponent feeds using a relatively low value refinery stream as a hydrogen source.

BACKGROUND

[0002] Fuels based on biocomponent sources will likely become increasingly prevalent in the future. Already, various governments have instituted current and future requirements that motor fuel pools contain a minimum percentage of fuel derived from a biocomponent source, such as a plant, animal, fish, or algae-based oil or fat.

[0003] Producing diesel fuel from biocomponent sources also presents a variety of challenges. In particular, for diesel hydroprocessing units that operate at low pressures, the presence of the additional heteroatoms in a biocomponent based diesel feed may pose difficulties. Modifying and/or replacing low pressure units to allow for higher processing pressures would require expensive capital investment.

[0004] For production of diesel fuel, vegetable oils such as canola oil, palm oil, or other similar oils have been identified as potentially suitable based on the carbon chain length of the vegetable oil. While some progress has been made toward stand alone processing and/or co-processing of biocomponent feeds, improvements to allow efficient processing in a refinery setting are greatly desired.

[0005] U.S. Patent Application Publication No. 2008/0154073 describes a process for removing oxygen from biocomponent molecules at low hydrogen pressure. The feed in this reference is exposed to a supported hydrogenation catalyst, such as Ni, NiMo, Pt, or Pd, in the presence of 150-290 psi hydrogen.

[0006] U.S. Patent Application Publication No. 2008/0161614 describes two stage co-processing of a feed including both vegetable/animal and mineral oil. According to this disclosure, the first stage is operated at lower severity to primarily treat the vegetable and/or animal oil in the feed. The product of the first stage is then stripped to remove gas phase impurities. The stripped product is then hydrotreated in a more severe hydrotreatment stage to produce a diesel fuel.

[0007] International Publication No. WO 2008/040980 describes reducing hydrogen consumption by controlling the products from reactions to remove oxygen from biocomponent feeds. Lower hydrogen pressures are mentioned as helping to reduce hydrogen consumption, but such pressures are mentioned as also leading to catalyst deactivation.

[0008] International Publication No. WO 2008/020048 describes a process for production of normal alkanes by hydrotreating mixtures of triglycerides or free fatty acids with vacuum gasoil. Conventional hydrotreatment catalysts are used in this process, which takes place at relatively mild conditions including a reaction pressure below 100 bars.

[0009] European Patent No. EP 1719811 describes a method for producing liquid hydrocarbons from biomass. The method includes forming an aqueous slurry of the biomass and particles of a layered catalyst, such as a clay. The slurry is heated to a temperature of 250-400°C. Up to 10 bars of hydrogen may optionally be added, although the publication indicates a preference to perform the process without added hydrogen.

[0010] European Patent No. EP 1741767 describes a process for producing diesel fuel from biocomponent sources. This reference states that the process reduces the needed hydrogen consumption by adding sulfur-containing compound to the

biocomponent feed.

[0011] European Patent No. EP 1693432 describes co-processing of vegetable oils with various diesel type mineral refinery feeds. The method appears to include combining vegetable oil and mineral oil, hydrotreating the combined oil, and stripping off gas phase products.

SUMMARY

[0012] One aspect of the invention relates to a method for hydroprocessing a biocomponent feedstock to form a diesel boiling range product, comprising: treating a purge gas and/or an off-gas stream from an existing refinery reactor to remove hydrogen sulfide and carbon dioxide, the treated refinery stream having a hydrogen content from about 20 mol% to about 60 mol%, for example from about 25 mol% to about 50 mol%; and hydroprocessing a feedstock comprising a biocomponent portion in a reactor in the presence of the treated refinery stream, a catalyst with hydrogenation activity, and optionally steam under effective hydroprocessing conditions to produce a vapor effluent, an aqueous effluent, and the diesel boiling range product.

[0013] Another aspect of the invention relates to a method for hydroprocessing a biocomponent feedstock to form a diesel boiling range product, comprising: treating a purge gas and/or an off-gas stream from an existing refinery reactor to remove hydrogen sulfide and carbon dioxide, the treated refinery stream having a hydrogen content from about 25 wt% to about 50 wt%; and hydroprocessing a feedstock comprising a biocomponent portion in a reactor in the presence of the treated refinery stream, a catalyst with hydrogenation activity, and optionally steam under effective

hydroprocessing conditions to produce a vapor effluent, an aqueous effluent, and the diesel boiling range product.

BRIEF DESCRIPTION OF THE FIGURES

[0014] Fig. 1 schematically shows a reaction system for performing a process according to an embodiment of the invention.

[0015] Fig. 2 schematically shows a reaction system for performing a process according to an embodiment of the invention.

[0016] Fig. 3 schematically shows a reaction system for performing a process according to an embodiment of the invention.

[0017] Fig. 4 schematically shows a reaction system for performing a process according to an embodiment of the invention.

[0018] Fig. 5 schematically shows a reaction system for performing a process according to an embodiment of the invention.

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