Hydroprocessing method for biological raw materials

Abstract

The present invention discloses a process for hydroprocessing of biomass feedstocks. The present invention relates to improved apparatus and methods for managing and utilizing light hydrocarbons utilized and produced during the hydroprocessing of biomass feedstocks in the production of middle distillate fuels.

Description

Technical Field

[0001] The present invention relates to improved apparatus and methods for managing and utilizing the light fraction, namely propane, produced during the hydroprocessing of biomass feedstock in the production of middle distillate fuels. Background Art

[0002] Recent years have been characterized by a rapid increase in demand for fuels, particularly diesel fuel bases, in the European Community, as well as the importance of issues related to global warming and greenhouse gas emissions. Consequently, there is a desire to reduce energy dependence on fossil-based raw materials and to reduce CO2 emissions.

[0003] In this context, the search for new methods for producing fuels from renewable sources that can be easily integrated into conventional refining and fuel production models is an increasingly important issue. Therefore, due to the rising cost of fossil fuels, there has been increasing interest in recent years in integrating new products of biological origin obtained by converting lignocellulosic biomass or by producing vegetable oils or animal fats into refining processes. The applicant's invention focuses on the latter - the production of biofuels, generally from vegetable oil and animal fat by-products. For an overview of green diesel technology and the catalysts used therein, see "Green Diesel: Biomass Feedstocks, Production Technologies, Catalytic Research, Fuel Properties and Performance in Compression Ignition Internal Combustion Engines", Douvartzides S., Charisiou N., Papageridis K. and Goula M. Energies 2019, 12, 809, which is incorporated herein by reference.

[0004] Furthermore, the methods known to date using vegetable oils or animal fats are resource-intensive and produce CO2, which is known for its negative impact on the environment. A more integrated approach to the production of these biofuels would therefore certainly be advantageous.

[0005] The production of fuel bases is therefore increasingly seen as an attractive new outlet for the agricultural world, particularly for vegetable oil producers who mill oilseeds such as rapeseed, soybeans, or sunflower seeds. These vegetable oils consist of fatty acids in the form of triglycerides with long alkyl chains whose structure corresponds to the n-paraffins of gas oil and kerosene fractions (chain length of 12 to 24 carbon atoms, depending on the nature of the vegetable oil). Because they are incompatible with modern diesel engines in their native state, these vegetable oils must be converted beforehand.

[0006] Two chemical pathways are commonly used to convert these biofeedstocks into middle distillate fuels: transesterification and hydroprocessing.

[0007] Transesterification utilizes alcohols, such as methanol, to produce vegetable oil methyl esters (VOME), commonly known as biodiesel. This route is now widely used in Europe, as VOME production has increased dramatically over the past decade, reaching 1.5 Mt in 2003 (with an average annual growth rate of 35% between 1992 and 2003). The European Directive (2003 / 30 / EC) promoting biofuels particularly supports this production, establishing targets for increasing biofuel consumption in the transportation sector. This consumption must reach at least 2% of global gasoline and diesel fuel consumption for transportation by 2005, 5.75% by 2010, and 8% by 2015 (measured in energy terms). However, this type of process is relatively expensive and requires limiting the type of vegetable oil that can meet biodiesel specifications. Furthermore, the feedstock for this type of process must be carefully selected, making many vegetable oils inoperable. Finally, the cold flow properties of these products are also a limiting factor.

[0008] As mentioned above, the hydroprocessing method consists in directly exploiting the vegetable oil by converting it into fatty acid derivatives by means of a hydrotreatment or hydroconversion process, the catalysts of which are also well known to those skilled in the art for their hydrodeoxygenation properties (see, for example, E. Laurent, Delmon B., Catal. App., 1994, Vol. 109, No. 1, pp. 77-97 and "Sunflower oil to green diesel over Raney-type Ni-catalyst", Onyestyak G., Harnow S., Szegedi A. and Kallo D, both of which are incorporated herein by reference).

[0009] Hydroprocessing is more commonly used commercially due to its ability to produce hydrocarbon products with greater stability and that are readily blended with hydrocarbons derived from mineral oils. In this case, triglycerides are converted primarily into paraffins and saturated derivatives, which thus constitute excellent hydrocarbon bases for diesel fuels due to their good cetane numbers.

[0010] In a typical renewable diesel plant configuration, hydrogen from a hydrogen station is fed along with pretreated biofeedstock to a hydroprocessing process that includes a hydrofinishing step and an isomerization step.

[0011] Biological raw materials need pretreatment usually, because the pollutants that cause trace elements to exist in animal fat and / or vegetable oil hinder the ability that these raw materials are catalytically converted into hydrocarbons in the hydroprocessing process.For example, some elements and the compounds containing these elements (for example phosphorus, phosphorus-containing compounds and metals, such as calcium and magnesium) poison hydroprocessing catalysts or reduce their activity, shorten their effective life and therefore improve the total cost of biofuel production. Therefore, the treatment method that reduces some pollutants (and therefore pollutants of raw materials) of the component that contains fatty acid or triglyceride to the greatest extent possible provides important commercial advantage in the hydroprocessing of biological raw materials into middle distillate products. Various different pretreatment schemes have been reported, and they provide different advantages and disadvantages separately.

[0012] Hydrorefining of triglycerides involves several different reactions. In the first reaction, hydrogen is added to saturate the double bonds of unsaturated vegetable oil triglycerides. In the second reaction, hydrogen is added to remove the propane backbone, thereby converting the saturated vegetable oil triglycerides into fatty acids. Finally, the fatty acids undergo hydrodeoxygenation (addition of more hydrogen results in the oxygen being removed as H₂O) or decarboxylation (the oxygen is removed as CO₂ without further hydrogen addition), or a combination of the two. The result is a mixture of straight-chain paraffins. The reaction scheme for the hydrorefining process is shown below.

[0013]

[0014] The alkane isomerization and cracking steps then result in biofuels of a quality equal to or better than the specifications of conventional petroleum fuels.

[0015] The effluent from the hydrotreating stage is then treated to separate lightened components from the liquid portion of the effluent. This can be accomplished in a number of ways, including by sending it to a stripping column where one or more components are removed from the liquid stream by means of a stripping vapor stream, typically superheated steam, to form a hydrocarbon fuel product. Alternatively, the effluent can be sent to a reboiler to separate the light ends.

[0016] It is also common to separate the liquid effluent into separate liquid products, either in the same distillation column as that in which the light ends are separated or in a separate distillation column; these liquid products typically may include a naphtha product, a kerosene product, and / or a diesel or gas oil product.

[0017] The invention described herein focuses on the interaction between the hydrotreating zone and the hydrogen station section. The hydrofinishing section produces several byproducts; some, such as water, originate from the hydrofinishing reaction, and some light ends are produced by minor cracking that occurs as a side reaction. One of the primary byproducts of hydrofinishing triglycerides is propane. Its management is therefore an important consideration. When the reactor effluent is separated into vapor and liquid, propane must be removed from the hydrofinishing loop; inadequately removed propane will accumulate in the recycle gas, thereby diluting the purity of the hydrogen sent to the hydrofinishing reactor.

[0018] The state of the art typically discharges propane in one of two ways. The first discharge of propane is typically as a high-pressure vapor discharge from the hydrotreating loop; this may be useful for sending the propane to a hydrogen station or for purification, but the discharge stream has a high concentration of valuable hydrogen, which can complicate or oversize the destination of the discharge stream. The second discharge of propane is typically as a low-pressure discharge from a tower that removes light ends from the liquid hydrotreating effluent; this approach typically uses propane as a low-value fuel or requires significant compression to send the propane to another destination. The propane generated by the hydrotreating reactions is typically too abundant to be used as a fuel for operating a hydrogen station and therefore the propane may be wastefully burned without generating value. In view of the foregoing, there is a need for processing schemes that more efficiently and effectively manage and utilize the propane generated by the hydrotreating of biofeedstocks in the manufacture of middle distillates.

[0019] The object of the present invention is therefore to establish a method for efficiently and effectively utilizing light fraction streams in combination with hydrotreatment of biological raw materials, comprising:

[0020] a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent;

[0021] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream; and

[0022] c) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce at least a portion of the hydrogen stream used in step (a).

[0023] Another object of the present invention is to establish a method for efficiently and effectively utilizing light fraction streams in combination with hydroprocessing of biological raw materials, comprising:

[0024] a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent;

[0025] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a stripped liquid effluent stream;

[0026] c) feeding the recovered light ends stream to a light ends separation zone to produce an LPG stream and a light residue gas stream; and

[0027] d) feeding the light residue gas stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the residue gas stream as feedstock to produce at least a portion of the hydrogen stream used in step (a).

[0028] Another object of the present invention is to establish a method for efficiently and effectively utilizing light fraction streams in combination with hydroprocessing of biological raw materials, comprising:

[0029] a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent;

[0030] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream;

[0031] c) feeding the gas-stripped liquid effluent stream to a secondary hydroprocessing zone which catalyzes additional hydroprocessing reactions utilizing at least one secondary solid catalyst to produce a secondary hydroprocessed liquid effluent;

[0032] d) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce a hydrogen-rich vapor effluent stream;

[0033] e) feeding the hydrogen-rich vapor effluent stream to the secondary hydroprocessing zone; and

[0034] wherein excess hydrogen from the secondary hydroprocessing zone is thereafter cascaded to the hydroprocessing zone. Summary of the Invention

[0035] The present invention relates to a method for efficiently and effectively utilizing a light fraction stream during a process for converting a biological feedstock into a middle distillate hydrocarbon fuel.

[0036] A first object / embodiment of the present invention is a method for hydroprocessing a biological feedstock comprising:

[0037] a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent;

[0038] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream; and

[0039] c) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce at least a portion of the hydrogen stream used in step (a).

[0040] A second object / embodiment of the present invention is a method for hydroprocessing a biological feedstock into a middle distillate hydrocarbon fuel comprising:

[0041] a) feeding a pretreated biomass feedstock and a hydrogen stream to a hydroprocessing zone, which catalyzes a hydrofining reaction using a solid catalyst and produces a hydroprocessed liquid effluent;

[0042] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a stripped liquid effluent stream;

[0043] c) feeding the recovered light ends stream to a light ends separation zone to produce an LPG stream and a light residue gas stream; and

[0044] d) feeding the light residue gas stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the residue gas stream as feedstock to produce at least a portion of the hydrogen stream used in step (a).

[0045] A third object / embodiment of the present invention is a method for hydroprocessing a biological feedstock comprising:

[0046] a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent;

[0047] b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream;

[0048] c) feeding the gas-stripped liquid effluent stream to a secondary hydroprocessing zone which catalyzes additional hydroprocessing reactions utilizing at least one secondary solid catalyst to produce a secondary hydroprocessed liquid effluent;

[0049] d) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce a hydrogen-rich vapor effluent stream;

[0050] e) feeding the hydrogen-rich vapor effluent stream to the secondary hydroprocessing zone; and

[0051] wherein excess hydrogen from the secondary hydroprocessing zone is thereafter cascaded to the hydroprocessing zone.

[0052] The process of the present invention, in particular the process of the present invention according to the first and second objects / embodiments of the present invention, may be designed so that the gas stripped liquid effluent stream is thereafter further treated using one or more processes selected from dissolved gas removal, liquid product fractionation, an isomerization reaction step and / or a hydrocracking reaction step to produce middle distillate hydrocarbon fuels.

[0053] The process of the present invention, particularly the process of the present invention according to the first and second objects / embodiments of the present invention, may be designed so that the gas stripped liquid effluent stream is thereafter further treated to produce middle distillate hydrocarbon fuels using an isomerization step which produces a hydrogen-rich vapor effluent stream and which is thereafter cascaded back to the hydroprocessing zone.

[0054] The process of the present invention, particularly the process of the present invention according to the first and second objects / embodiments of the present invention, may be designed so that the gas stripped liquid effluent stream is thereafter further treated to produce middle distillate hydrocarbon fuels using a hydrocracking step which produces a hydrogen-rich vapor effluent stream and which is thereafter cascaded back to the hydroprocessing zone.

[0055] In the process according to the present invention, the hydrotreatment zone and / or the secondary hydrotreatment zone may be operated at a temperature of 145°C to 400°C, a pressure of 10 bar to 150 bar and a temperature of 0.1 to 10 h. -1 Run under LHSV.

[0056] In the process according to the present invention, the solid catalyst may comprise a hydrodeoxygenation function comprising at least one Group VIII metal selected from cobalt and nickel, at least one Group VIB metal selected from molybdenum and tungsten, or a mixture of at least one Group VIII metal selected from cobalt and nickel and at least one Group VIB metal selected from molybdenum and tungsten on a support comprising alumina, silica, silica-alumina, magnesia, clay or a mixture of at least two of these minerals.

[0057] According to the present invention, the light ends recovery zone may be operated at a pressure greater than 5 bar.

[0058] In the process according to the present invention, the hydroprocessing zone in step a) may produce a vapor effluent, and the vapor effluent may be further separated into a hydrocarbon-rich stream and a hydrogen-rich stream using, for example, a membrane; and the hydrocarbon-rich stream may thereafter be mixed with the recovered light fraction stream, and the hydrogen-rich stream and the mixture of the hydrocarbon-rich stream and the recovered light fraction stream may be sent to the hydrogen-producing zone, respectively.

[0059] In the process according to the invention, part of the hydrogen stream produced in step c) or d) may be used for hydrotreatment outside the hydrotreatment zone.

[0060] In the process according to the invention, in particular according to the first object / embodiment of the invention, at least a portion of the hydrogen coming from the hydrogen production zone may be sent to an isomerization step before cascading said excess hydrogen to the hydroprocessing zone, and the liquid effluent of the gas stripping may be further treated in said isomerization step to produce middle distillate hydrocarbon fuels.

[0061] In the process according to the invention, the light hydrocarbon stripping medium may be a stream comprising methane, ethane, natural gas, fuel gas, deethanizer lights, demethanizer lights, a stream obtained from another renewable source, such as light gases from a biomass pyrolysis unit or from a gas digester unit or from a waste and / or plastic pyrolysis unit or from any other unit processing renewable raw materials, or a mixture thereof.

[0062] In the process according to the invention, the hydrotreatment zone may comprise a hydrofinishing step and an isomerization step and / or the secondary hydrotreatment zone may comprise an isomerization step.

[0063] In the process according to the present invention, the hydroprocessing zone may comprise a hydrofinishing step and an isomerization step and / or the secondary hydroprocessing zone may comprise an isomerization step, and the isomerization step may use at least one solid isomerization catalyst different from the solid catalyst.

[0064] In the case where the process according to the present invention includes the above-mentioned isomerization step, the solid isomerization catalyst that can be used particularly comprises an isomerization functional substance containing at least one metal selected from palladium (Pd) and platinum (Pt), and a support comprising zeolite, alumina, silica, silica-alumina, magnesia, clay.

[0065] In the case where the process according to the present invention includes the above-mentioned isomerization step, useful solid isomerization catalysts especially comprise an isomerization functional substance on a support, the isomerization functional substance comprising at least one Group VIB metal selected from molybdenum and tungsten, at least one Group VIII metal selected from nickel and cobalt, or a combination of at least one Group VIB metal selected from molybdenum and tungsten and at least one Group VIII metal selected from nickel and cobalt, the support comprising zeolite, alumina, silica, silica-alumina, magnesia, clay and a mixture of at least two of these minerals.

[0066] In the process according to the present invention, the hydroprocessing zone and / or the secondary hydroprocessing zone may comprise a hydrofinishing step and an isomerization step, and the isomerization step is preferably carried out within a time range of 0.1 to 10 h. -1 Run under LHSV.

[0067] In the method of the present invention, the hydroprocessing zone may include a hydrofinishing step and an isomerization step, and an interstage separation step may exist between the hydrofinishing step and the isomerization step to separate light gas from the middle distillate hydrocarbon fuel.

[0068] The recovered light ends stream may be mixed with an additional feed stream before being fed to the hydrogen production zone.

[0069] The recovered light ends stream may be mixed with an additional feed stream before being fed to the hydrogen-producing zone, and the additional feed stream may be supplied from the same source that supplies the light hydrocarbon stripping medium, or the additional feed stream may be supplied from a different source than the light hydrocarbon stripping medium.

[0070] According to the present invention, the light ends recovery zone may further comprise an amine absorption step to remove acid gases.

[0071] According to the present invention, the light ends recovery zone may further comprise an adsorbent to remove components such as H2O, H2S, CO2, light sulfur hydrocarbons, or any combination thereof.

[0072] According to the present invention, the biological raw material can be selected from: rapeseed oil, soybean oil, corn oil, coconut oil, olive oil, linseed oil, sunflower oil, palm oil, jatropha oil, mustard oil, peanut oil, hemp oil, cottonseed oil, pork fat, poultry fat, lard, butter, tallow or any combination thereof.

[0073] In particular according to the second object / embodiment of the present invention, the light ends separation zone may produce, in addition to the LPG stream and the light residue gas stream, a liquid product stream comprising naphtha range hydrocarbons heavier than n-butane.

[0074] In particular according to the third object / embodiment of the present invention, the secondary hydrotreated liquid effluent stream may thereafter be further processed using one or more processes selected from dissolved gas removal and / or liquid product fractionation to produce middle distillate hydrocarbon fuels.

[0075] In particular according to the third aspect / embodiment of the present invention, the light ends recovery zone may include a dissolved gas removal step to separate light gases from the middle distillate hydrocarbon fuel after contacting the hydrotreated liquid effluent with a light hydrocarbon stripping medium.

[0076] According to the present invention, the biomass feedstock can be a mixture with a petroleum hydrocarbon feedstock or co-fed therewith, and the petroleum hydrocarbon feedstock can be co-processed with the biomass feedstock. Optionally, the petroleum hydrocarbon feedstock is selected from LCO light cycle oil, diesel, kerosene, HCGO, LCGO, VGO or pyrolysis oil or any combination thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 Schematic diagram showing applicant's novel process for the efficient and effective utilization of light ends streams in a process for converting biological feedstocks to middle distillate range hydrocarbons. Detailed Description of the Invention

[0078] Figure 1 Schematic diagram showing applicant's novel process for the efficient and effective utilization of light-end streams in a process for converting biomass feedstocks into middle distillate range hydrocarbon fuels.

[0079] As used herein, "hydrofining" refers to the chemical reactions between a hydrocarbon feedstock and hydrogen, including hydrodenitrogenation, hydrodesulfurization, hydrodeoxygenation, hydrogenolysis, and olefin saturation; the term is also used herein to include decarboxylation and decarbonylation, since these reactions occur simultaneously as competing reactions with hydrogenolysis under given reaction conditions.

[0080] As used herein, a "hydroprocessing zone" refers to a zone in which hydrofinishing and / or hydrotreating reactions occur between the hydrocarbon feedstock and hydrogen when in contact with a catalyst bed. In addition to one or more catalyst beds, the hydroprocessing zone may also include one or more of the following: separation of one or more liquid streams and one or more vapor streams downstream of the one or more catalyst beds, a recycle gas loop, one or more recycle liquid loops, and an amine separation for removing hydrogen sulfide and / or carbon dioxide. Furthermore, the hydroprocessing zone may also include an isomerization and / or hydrocracking step using different catalysts to promote isomerization / hydrocracking of the paraffins.

[0081] As used herein, "middle distillates" refers to hydrocarbon fuels generally composed primarily of hydrocarbon components having a boiling point above 150°C, including, for example, kerosene, diesel, or gas oil.

[0082] As used herein, "biogenic feedstock" refers to vegetable oils, animal fats, tall oil, and derived materials such as fatty acid alkyl esters, or combinations thereof. Vegetable oils include, but are not limited to, rapeseed oil, soybean oil, corn oil, coconut oil, olive oil, linseed oil, sunflower oil, palm oil, jatropha oil, mustard oil, peanut oil, hemp oil, and cottonseed oil. Animal fats include, but are not limited to, pork fat, poultry fat, lard, butter, and tallow.

[0083] As used herein, the term light fraction or light hydrocarbons refers to chemical compounds lighter than pentane, including methane, ethane, propane, n-butane or isobutane. Such light hydrocarbons or "light fractions" are often used as feedstock and / or as fuel in some hydrocarbon processing schemes.

[0084] As used herein, LHSV is the liquid hourly space velocity, which is the ratio of the volume flow of liquid per hour to the volume of catalyst. 3 / h flow rate and 1m 3 The catalyst system has an LHSV of 2. (Unit is 1 / hr). LHSV is inversely proportional to residence time.

[0085] Pretreated biomass feedstock stream 11 is fed to hydroprocessing zone 17 along with hydrogen stream 16 from hydrogen production zone 15. Hydrogen production zone 15 is typically the section where hydrogen is chemically produced from a hydrocarbon feed stream.

[0086] Although not shown, the pretreated biomass stream can be processed together with another compatible feed, particularly a feed of petroleum origin, such as LCO light cycle oil, diesel, kerosene, HCGO, LCGO, VGO or pyrolysis oil or any combination thereof, provided that some adjustments to the design are made as known to those skilled in the art. Depending in particular on the amount of feed being co-processed, the present invention may also include a desulfurization step, such as an amine treatment or a sulfur capture adsorbent in the light ends recovery section, in addition to the conventional sulfur guard used to protect the hydrogen production unit. In practice, catalysts used in SMR or other technologies require low H2S feed levels. The pretreated biomass content may be from 100% to 50% by weight of the total feed, preferably from 99% to 60% by weight, more preferably from 95% to 60% by weight, and even more preferably from 93% to 80% by weight of the total feed. These ranges are most suitable for being able to use propane produced more specifically in the hydrofining process of the biomass.

[0087] However, in an embodiment of the present invention where the hydroprocessing of a compatible feed produces a significant amount of light ends, it may be of interest to co-process more than 50% of the co-feed and up to 90%. An example of such an embodiment is where the compatible feed is a VGO boiling range hydrocarbon and the hydroprocessing zone includes a hydrocracking catalyst. As is known in the art, hydrocracking processing of hydrocarbon components produces significant amounts of light end hydrocarbon components. This embodiment of the present invention then enables the recovery of these light end components to supplement the bio-derived propane in hydrogen production.

[0088] Although not shown, a "hydrogen generation step" is utilized, such as steam methane reforming (SMR), autothermal reforming, or partial oxidation. This section typically includes a sulfur guard upstream of the hydrogen generation step and a hydrogen purification step downstream of the hydrogen generation step. The hydrogen purification step typically utilizes pressure swing adsorption (PSA), but other methods such as amine absorption and methanation may also be used. While applicants refer to steam reforming in this specification, any hydrogen production technology known to those skilled in the art can be used for the same purpose.

[0089] In the hydrofinishing step, hydrogen from hydrogen stream 16 is added to saturate the double bonds of the unsaturated vegetable oil triglycerides from biological feedstock 11 and remove the propane backbone, thereby converting the saturated vegetable oil triglycerides into fatty acids. Finally, the fatty acids undergo hydrodeoxygenation (by adding more hydrogen, with the oxygen leaving as H₂O) or decarboxylation (with no further hydrogen added, the oxygen leaves as CO₂), or a combination of the two. The result is a liquid hydrotreating effluent stream 18 comprising a mixture of paraffins and light ends. This hydrofinishing step in hydrotreating zone 17 utilizes a solid catalyst to catalyze the hydrofinishing reactions.

[0090] Catalysts known in the art typically use Group VIII metals, such as nickel or cobalt, alone or in combination with Group VIB metals, such as molybdenum or tungsten. Well-known catalyst types in the art are sulfided forms of NiMo, CoMo, and NiW on alumina supports, as well as reduced nickel. Depending on the specific biomass feedstock, the reaction is typically carried out at a reaction temperature of typically 180° C. to 400° C., a pressure of 10 bar to 150 bar, and a reaction time of 0.1 to 10 h. -1 Run under LHSV.

[0091] Hydroprocessing zone 17 may also include a catalyst capable of isomerizing and cracking the linear paraffins after the hydrofinishing reaction has occurred. The isomerization / cracking catalyst may be present in a stage separate from the hydrofinishing reaction or in the same stage as the hydrofinishing reaction. In those cases where hydroprocessing zone 17 includes an isomerization / hydrocracking step, hydroprocessing effluent stream 18 comprises the liquid effluent from the isomerization / hydrocracking step.

[0092] The hydroprocessing zone 17 may include equipment capable of recycling excess hydrogen and / or liquid effluent from one or more reactors back to one or more reaction vessels. The hydroprocessing zone may also selectively separate carbon dioxide from the reactor effluent using techniques such as amine absorption or membrane separation.

[0093] Liquid hydrotreating effluent stream 18 comprising a mixture of paraffins is thereafter fed along with light hydrocarbon stripping medium 10a to a light ends recovery zone 19. The light ends recovery zone may utilize a single stage contactor, but typically uses a single vessel having multiple stages, such as a distillation column.

[0094] The light ends recovery zone 19 of applicant's invention operates at high pressure, and as explained in detail below, the light hydrocarbon stripping medium 10a used to remove propane from the hydroprocessing reactor liquid effluent is also suitable for and used as the feed to the hydrogen production zone. The light hydrocarbon stripping medium 10a is typically a vapor stream composed primarily of light hydrocarbons, such as methane or natural gas.

[0095] Although not shown Figure 1 It is, however, also possible that the light hydrocarbon stripping medium is obtained from another renewable source, such as light gases from a biomass pyrolysis unit or from a gas digester unit or from a waste and / or plastic pyrolysis unit or from any other unit processing renewable raw materials.

[0096] It is advantageous to use the same light hydrocarbon stripping medium as the feed stream to hydrogen production zone 15 since it must be present at a moderate pressure to enter the hydrogen production system, such as a steam reformer.

[0097] Therefore, its use as the stripping medium in the light ends recovery zone 19 enables it to be operated at high pressure.

[0098] Propane, the primary by-product of the hydrotreating reaction, is a suitable feedstock for a variety of hydrogen production processes. By utilizing a light ends recovery zone, the light ends produced in the hydrotreating zone, i.e., propane, can be used to produce hydrogen; this allows hydrogen to be produced at least partially from renewable feedstocks and reduces the amount of feedstock that must be imported from other sources.

[0099] Hydroprocessing liquid effluent stream 18 is separated in light ends recovery zone 19 into a recovered light ends vapor stream 20 and a gas stripped liquid effluent stream 22. Recovered light ends stream 20 typically comprises propane, other light ends produced in hydroprocessing zone 17, and components of light hydrocarbon stripping medium 10a.

[0100] The gas stripping liquid effluent stream 22 typically contains paraffins and is thereafter suitable for further processing into saleable products, including diesel fuel, kerosene, jet fuel, gas oil, and / or naphtha, by a number of methods known to those skilled in the art. The gas stripping liquid effluent stream 22 may also contain dissolved light ends from the light hydrocarbon recovery zone; when separated, these light ends can be used as fuel gas after further processing.

[0101] Hydrogen production zone 15 typically includes a sulfur guard, a steam reformer, and a pressure swing adsorption (PSA) stage (none shown). A hydroprocessing zone effluent stream 14, comprising hydrogen and other light ends, is optionally fed to hydrogen production zone 15 upstream of the sulfur guard, steam reformer, or PSA. If fed upstream of the steam reformer, the hydrocarbons in hydroprocessing zone effluent stream 14 can be converted to hydrogen. Alternatively, if conversion of the light ends in this stream is not desired, hydroprocessing zone effluent stream 14 can be fed to a PSA; this may be more desirable in some circumstances because this stream is typically rich in hydrogen.

[0102] As mentioned above, using the same light hydrocarbon stripping medium 10a as the feed stream to hydrogen-producing zone 15 brings processing efficiencies. Figure 1 This embodiment is shown wherein light hydrocarbon feed stream 10 is used as light hydrocarbon stripping medium 10a and hydrogen production zone feed stream 10b. Hydrogen production feed stream 10b is thereafter combined with recovered light ends stream 20 and combined stream 12 is used as fuel and sent to hydrogen production zone 15.

[0103] Typically, the feed (natural gas or other) to hydrogen-producing zone 15 requires compression for entry into the unit. In this case, the compressed feed can be used as the stripping medium as described above, but a similar effect can be achieved by operating light ends recovery zone 19 at low pressure using low-pressure light ends feed stream 10a gas and then cascading the recovered light ends stream 20 to a compression step; this allows the recovered light ends stream 20 and hydrogen-producing zone feed stream 10b to share compression equipment.

[0104] Although not shown Figure 1However, it is also possible that the gas stripped liquid effluent stream 22 may first be sent to an isomerization or hydrocracking step together with the hydrogen stream 16 to produce middle distillate fuels and wherein the excess hydrogen not utilized in the isomerization or hydrocracking process is thereafter cascaded to the hydrotreating zone 17.

[0105] Although not shown and depending on the specifications of the particular plant, the hydrogen production feed stream 10b and the light hydrocarbon stripping medium 10a can come from separate sources. In addition, and although also not shown, the hydrogen production feed stream 10b and the recovered light ends stream 20 can be sent to the hydrogen production zone 15 in separate streams.

[0106] In some applications, it may be valuable to recover the propane component of the recovered light ends stream 20 as a saleable liquid product. In this case and although not shown in FIG. Figure 1 In the process, the recovered light ends stream 20 can be sent to the liquefied petroleum gas (LPG) recovery section.

[0107] "Liquefied petroleum gas, or LPG," is typically composed of propane, butane, or a mixture thereof. The LPG recovery stage can utilize membranes, fractionation, or some combination thereof to recover propane. In this step, liquids are removed from recovered light ends stream 20, allowing the propane or LPG to be sold. The remaining recovered light ends stream 20, containing light gases such as methane and / or ethane, can then be used as feed to a steam reformer or as fuel.

[0108] The invention described herein has been disclosed with respect to specific embodiments and applications. However, these details are not intended to be limiting, and other embodiments will be apparent to those skilled in the art based on this teaching. It will be understood, therefore, that the drawings and description illustrate the principles of the invention and should not be construed as limiting its scope. Specific implementation:

[0110] The present invention is further described by the following examples, which should not be construed as limiting the scope of the invention.

[0111] In accordance with Figure 1 A pretreated biomass feedstock stream 11 consisting of soybean oil and a hydrogen stream 16 from a hydrogen production section 15 are processed in a unit. The hydrogen production section 15 is a steam methane reforming (SMR) unit.

[0112] The relevant properties of this feed are listed in Table 1 below:

[0113] Table 1

[0114] source unit standard Pretreated soybean oil Specific gravity d15 / 4 D4052 / D1298 0.923 Fatty acid composition NF EN ISO 12966.2 + NF EN ISO 5508 C14:0 weight% 0.5 C14:1 weight% 0.0 C15:0 weight% 0.0 C16:0 weight% 10.0 C16:1 weight% 0.0 C17:0 weight% 0.0 C17:1 weight% 0.0 C18:0 weight% 4.0 C18:1 weight% 23.0 C18:2 weight% 53.0 C18:3 weight% 8.0 C20:0 weight% 0.5 C20:1 weight% 0.5 C22:0 weight% 0.0 C22:1 weight% 0.5 Glyceride composition NF EN ISO 12966.2 + NF EN ISO 5508 Free fatty acids weight% 0.5 Monoglycerides weight% 0.0 diglycerides weight% 0.0 triglycerides weight% 99.5 fatty acid methyl esters weight% 0.0 total weight% 100.0 Sulfur FX or UV Weight ppm D2622 / D5453 10 Total nitrogen Weight ppm D4629 / D5762 20 phosphorus Weight ppm D5185 3 Metal Weight ppm D5185 5

[0115] In the hydrofinishing step, hydrogen is added to saturate the double bonds of the unsaturated vegetable oil triglycerides from the biological feedstock 11 and remove the propane backbone, thereby converting the saturated vegetable oil triglycerides into fatty acids. Finally, the fatty acids undergo hydrodeoxygenation (with the addition of more hydrogen, the oxygen is removed as H2O) or decarboxylation (with the oxygen removed as CO2 without further hydrogen addition), or a combination of the two. The result is a liquid hydrotreating effluent stream 18 comprising a mixture of paraffins and light ends.

[0116] This hydrofinishing step in the hydroprocessing zone 17 utilizes a sulfided NiMo catalyst on an alumina support. The catalyst contains 4 wt% nickel and 14 wt% molybdenum.

[0117] Table 2 below shows the operating conditions of the hydrotreating unit:

[0118] Table 2

[0119] Operating conditions According to the present invention Existing technology using propane high pressure discharge Existing technology using propane low pressure discharge Reactor pressure MPa 10.6 10.6 10.6 WABT (HDO / HDT) ℃ 340 343 343 <![CDATA[HDO / HDT catalyst LHSV h -1 > 0.25 0.25 0.25

[0120] Hydroprocessing zone 17 does not include any selective separation of carbon dioxide from the reactor effluent.

[0121] The liquid hydrotreating effluent stream 18, comprising a mixture of paraffinic hydrocarbons, is then fed to a light ends recovery zone 19 along with a light hydrocarbon stripping medium 10a. The light ends recovery zone utilizes a distillation column operating at high pressure (3 MPa), and the light hydrocarbon stripping medium 10a used to remove propane from the hydrotreating reactor liquid effluent is used as a feed to the hydrogen production zone. The light hydrocarbon stripping medium 10a is a vapor stream composed of light hydrocarbons having the composition shown in Table 3 below.

[0122] Table 3

[0123] .

[0124] Hydroprocessed liquid effluent stream 18 is separated in light ends recovery zone 19 into recovered light ends vapor stream 20 and a gas stripped liquid effluent stream 22. Recovered light ends stream 20 comprises propane, other light ends produced in hydroprocessing zone 17, and components of light hydrocarbon stripping medium 10a.

[0125] Table 4 below shows the product yields according to the present invention and according to the prior art:

[0126] Table 4

[0127] .

[0128] Propane is sent from the recovery zone to the SMR unit along with the light fractions. This allows hydrogen to be produced at least in part from renewable feedstocks and a corresponding reduction in the input feedstock to the SMR unit. The hydrogen from the hydrotreating section that is discharged to the SMR in prior art solutions requires additional fuel consumption and hydraulic capacity of the SMR without beneficially contributing to hydrogen production; the large amount of hydrogen discharged to the SMR therefore represents a significant inefficiency of the process. Indeed, according to Table 4, the H2 discharged from the hydrotreating section to the SMR is reduced by 50 wt%, and the propane can be recovered and sent to the SMR without additional compression. In this way, the proposed invention is able to provide the advantages of high-pressure and low-pressure propane removal without incurring the severe inefficiencies of either option. This can be roughly quantified by an "equivalent H2 savings", which represents the difference between the stoichiometric hydrogen production capacity of the propane sent to the SMR and the sum of the H2 discharged to the SMR and lost to the fuel.

[0129] In view of the above, the processing scheme according to the present invention is more efficient and utilizes propane generated by hydroprocessing of biomass feedstock in the production of middle distillates.

Claims

1. A method for hydrotreating a biomass feedstock, comprising: a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent; b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream; and c) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce at least a portion of the hydrogen stream used in step (a), wherein the light hydrocarbon stripping medium is suitable for and used as a feed to the hydrogen production zone, and the recovered light ends stream comprises propane, other light ends produced in the hydroprocessing zone, and components of the light hydrocarbon stripping medium, The biological raw material is selected from the group consisting of rapeseed oil, soybean oil, corn oil, coconut oil, olive oil, linseed oil, sunflower oil, palm oil, jatropha oil, mustard oil, peanut oil, cottonseed oil, pork fat, poultry fat, lard, butter, beef tallow, or any combination thereof.

2. A method for hydrotreating a biomass feedstock into a middle distillate hydrocarbon fuel, comprising: a) feeding a pretreated biomass feedstock and a hydrogen stream to a hydroprocessing zone, which catalyzes a hydrofining reaction using a solid catalyst and produces a hydroprocessed liquid effluent; b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a stripped liquid effluent stream; c) feeding the recovered light ends stream to a light ends separation zone to produce an LPG stream and a light residue gas stream; and d) feeding the light residue gas stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the light residue gas stream as a feedstock to produce at least a portion of the hydrogen stream used in step (a), wherein the light hydrocarbon stripping medium is suitable for and used as a feed to the hydrogen production zone, and the recovered light ends stream comprises propane, other light ends produced in the hydroprocessing zone, and components of the light hydrocarbon stripping medium, The biological raw material is selected from the group consisting of rapeseed oil, soybean oil, corn oil, coconut oil, olive oil, linseed oil, sunflower oil, palm oil, jatropha oil, mustard oil, peanut oil, cottonseed oil, pork fat, poultry fat, lard, butter, beef tallow, or any combination thereof.

3. The process according to claim 1 or 2, wherein the gas stripped liquid effluent stream is thereafter further treated to produce middle distillate hydrocarbon fuels using one or more processes selected from dissolved gas removal, liquid product fractionation, an isomerization reaction step and / or a hydrocracking reaction step.

4. The process according to claim 1 or 2, wherein the gas stripped liquid effluent stream is thereafter further treated with an isomerization step to produce middle distillate hydrocarbon fuels, wherein the isomerization step produces a hydrogen-rich vapor effluent stream, and wherein the hydrogen-rich vapor effluent is thereafter cascaded back to the hydroprocessing zone.

5. The process according to claim 1 or 2, wherein the gas stripped liquid effluent stream is thereafter further treated with a hydrocracking step to produce middle distillate hydrocarbon fuels, wherein the hydrocracking step produces a hydrogen-rich vapor effluent stream, and wherein the hydrogen-rich vapor effluent is thereafter cascaded back to the hydroprocessing zone.

6. The process according to claim 2, wherein said light ends separation zone produces, in addition to said LPG stream and said light residue gas stream, a liquid product stream comprising naphtha range hydrocarbons heavier than n-butane.

7. A method for hydrotreating a biomass feedstock, comprising: a) feeding a pretreated biofeedstock and a hydrogen stream to a hydroprocessing zone which catalyzes a hydrofinishing reaction using at least one solid catalyst and produces a hydroprocessed liquid effluent; b) feeding the hydrotreated liquid effluent and a light hydrocarbon stripping medium to a light ends recovery zone, wherein the light hydrocarbon stripping medium is contacted with the hydrotreated liquid effluent to produce a recovered light ends stream and a gas stripped liquid effluent stream; c) feeding the gas-stripped liquid effluent stream to a secondary hydroprocessing zone which catalyzes additional hydroprocessing reactions utilizing at least one secondary solid catalyst to produce a secondary hydroprocessed liquid effluent; d) feeding the recovered light ends stream to a hydrogen production zone, wherein the hydrogen production zone utilizes hydrocarbons in the recovered light ends stream as a feedstock to produce a hydrogen-rich vapor effluent stream; e) feeding the hydrogen-rich vapor effluent stream to the secondary hydroprocessing zone; and wherein excess hydrogen from the secondary hydroprocessing zone is thereafter cascaded to the hydroprocessing zone, wherein the light hydrocarbon stripping medium is suitable for and used as a feed to the hydrogen production zone, and the recovered light ends stream comprises propane, other light ends produced in the hydroprocessing zone, and components of the light hydrocarbon stripping medium, The biological raw material is selected from the group consisting of rapeseed oil, soybean oil, corn oil, coconut oil, olive oil, linseed oil, sunflower oil, palm oil, jatropha oil, mustard oil, peanut oil, cottonseed oil, pork fat, poultry fat, lard, butter, beef tallow, or any combination thereof.

8. The process according to claim 1, 2 or 7, wherein the light ends recovery zone is operated at a pressure greater than 5 bar.

9. The process of claim 1 , 2 or 7 , wherein the hydrotreating zone in step a) produces a vapor effluent, and wherein the vapor effluent is further separated into a hydrocarbon-rich stream and a hydrogen-rich stream, and wherein the hydrocarbon-rich stream is thereafter mixed with the recovered light ends stream, and wherein the hydrogen-rich stream and the mixture of the hydrocarbon-rich stream and the recovered light ends stream are separately sent to the hydrogen-producing zone.

10. The process according to claim 1, 2 or 7, wherein a portion of the hydrogen stream produced in step c) or d) is used for hydroprocessing outside the hydroprocessing zone.

11. A process according to claim 1, 2 or 7, wherein at least a portion of said hydrogen coming from the self-produced hydrogen zone is sent to an isomerization step before cascading excess hydrogen to a hydroprocessing zone, and wherein the liquid effluent from said gas stripping is further processed in said isomerization step to produce middle distillate hydrocarbon fuels.

12. The process according to claim 1 , 2 or 7, wherein the light hydrocarbon stripping medium is a stream comprising methane, ethane, natural gas, deethanizer lights, demethanizer lights, a stream obtained from another renewable source, light gases from a biomass pyrolysis unit or from a gas digester unit or from a waste and / or plastic pyrolysis unit or from any other unit processing renewable feedstocks, or a mixture thereof.

13. The process of claim 1, 2 or 7, wherein the hydrotreating zone comprises a hydrofinishing step and an isomerization step, and / or the secondary hydrotreating zone comprises an isomerization step.

14. The process of claim 1 , 2 or 7 wherein the hydrotreating zone comprises a hydrofinishing step and an isomerization step, and / or the secondary hydrotreating zone comprises an isomerization step, and wherein the isomerization step utilizes at least one solid isomerization catalyst that is different from the solid catalyst.

15. The process of claim 1, 2 or 7, wherein the hydrotreating comprises a hydrofinishing step and an isomerization step, and wherein there is an interstage separation step between the hydrofinishing step and the isomerization step, wherein light gases are separated from middle distillate hydrocarbon fuels.

16. The process of claim 1, 2 or 7, wherein the recovered light ends stream is mixed with an additional feed stream prior to being fed to the hydrogen production zone.

17. The process of claim 1, 2 or 7, wherein the recovered light ends stream is mixed with an additional feed stream prior to being fed to the hydrogen production zone and wherein: The additional feed stream is supplied from the same source that supplies the light hydrocarbon stripping medium, or the additional feed stream is supplied from a different source than the light hydrocarbon stripping medium.

18. The process according to claim 7, wherein the secondary hydrotreated liquid effluent is thereafter further processed to produce middle distillate hydrocarbon fuels using one or more processes selected from dissolved gas removal and / or liquid product fractionation.

19. The process of claim 7 wherein the light ends recovery zone includes a dissolved gas removal step wherein light gases are separated from the middle distillate hydrocarbon fuel after contacting the hydroprocessed liquid effluent with the light hydrocarbon stripping medium.

20. The process according to claim 1, 2 or 7, wherein the biomass feedstock is a mixture or co-fed with a petroleum hydrocarbon feedstock and the petroleum hydrocarbon feedstock is co-processed with the biomass feedstock, optionally wherein the petroleum hydrocarbon feedstock is selected from LCO light cycle oil, diesel, kerosene, HCGO, LCGO, VGO or pyrolysis oil or any combination thereof.

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