Co-Processing of Biomass During Fluidized Coking with Gasification

Systems and methods are provided for co-processing biomass in a reaction system for performing fluidized coking and gasification, where the reaction system includes at least one intervening reactor vessel for heat transfer between the fluidized coker and the gasifier.

One area of focus for reducing net greenhouse gas emissions from energy production, or more generally for production of carbon-based products, is to use biomass and/or fractions derived from biomass as the source for at least part of the carbon in a fuel or other carbon-based product. Because biomass removes COfrom the environment as it grows, the net COgenerated by combustion of a fuel derived from biomass is offset by the COconsumed during the growth of the biomass.

Due to the difficulties in handling solid biomass in many types of refinery equipment a common technique for processing biomass is to use an initial pyrolysis stage to convert the biomass. Instead of having to build a dedicated pyrolysis reactor for handling biomass, it would be desirable to use existing refinery facilities for processing of biomass. A fluidized coker is an example of an existing refinery process that can potentially co-process biomass.

Some types of fluidized coker reaction systems correspond to systems that use three reaction vessels. The three reaction vessels correspond to a coker reactor, an intermediate heater, and a gasifier. In this type of three reaction vessel configuration, instead of forming COduring the gasification process, the overhead gas can instead optionally correspond to a gas stream that includes synthesis gas components. It would be desirable to develop improved methods for co-processing biomass in such three-vessel fluidized reactor systems.

U.S. Patent Application Publication 2018/0118644 describes performing both partial oxidation and pyrolysis of biomass within the same reactor environment, so that the heat for the pyrolysis reaction can be generated in-situ by the partial oxidation.

U.S. Patent Application Publication 2005/0095183 describes a multi-stage gasification system for conversion of biomass or municipal solid waste into a synthesis gas product while reducing the amount of carbon char and/or tar in the product.

U.S. Patent Application Publication 2019/0144756 describes methods for fluidized coking with increased liquids production.

In an aspect, a method for co-processing biomass in a fluidized coking system is provided. The method includes exposing a feed containing 1.0 wt % to 60 wt % of biomass and 40 wt % to 99 wt % of a mineral fraction having a T10 distillation point of 500° C. or higher, to a fluidized bed of particles under fluidized coking conditions in a reactor vessel to form i) a coker effluent having a liquid portion, ii) char, coke, or a combination thereof, at least a portion of the char, coke, or combination thereof being deposited on the particles to form particles comprising deposited char, coke, or a combination thereof, and iii) additional hydrocarbons associated with the particles comprising deposited char, coke, or a combination thereof. The method further includes passing at least a portion of particles comprising deposited char, coke, or a combination thereof from the reactor vessel into a heater vessel. The at least a portion of particles comprising deposited char, coke or a combination thereof can contain 0.08 wt % or less of the associated additional hydrocarbons, relative to a weight of the feed. The method further includes mixing the at least a portion of the particles comprising deposited char, coke, or a combination thereof with a portion of partially gasified particles in the heater vessel to form a heated particle mixture. The method further includes passing a first portion of the heated particle mixture into the reactor vessel. The method further includes passing a second portion of the heated particle mixture into a gasification vessel. The method further includes introducing an oxygen-containing stream and steam into the gasification vessel. The method further includes exposing the second portion of the heated particle mixture to oxidation conditions in the gasification vessel to form a gas phase product, and partially gasified particles. Additionally, the method includes passing at least a portion of the partially gasified particles from the gasification vessel to the heater vessel. In some aspects, the liquid portion of the coker effluent can have a micro carbon residue content of 0.5 wt % or less, an n-heptane insolubles content of 0.5 wt % or less, or a combination thereof.

In another aspect, a liquid product is provided. The liquid product can be, for example, the liquid portion of a coker effluent. The liquid product includes 30 wt % to 50 wt % of naphtha boiling range components, 30 wt % to 50 wt % of heavy distillate boiling range components, 10 wt % to 25 wt % of light distillate boiling range components, and 5.0 wt % or less of vacuum resid boiling range components. Additionally, the liquid product can contain 0.9 wt % to 3.0 wt % of oxygen. Additionally, the liquid product can contain a) 0.05 wt % to 0.5 wt % of micro carbon residue content, b) 0.05 wt % to 0.5 wt % of n-heptane insolubles, or c) a combination of a) and b).

All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

In various aspects, systems and methods are provided for integrated coking and gasification of a biomass feed in a three-vessel fluidized coking system under co-processing conditions so that biomass is co-fed with a conventional and/or mineral coker feed, such as a feed containing resid or heavy crude oil. It has been discovered that co-processing of a biomass feed can unexpectedly increase the reaction rate for coking of the conventional/mineral coker feed. This unexpected increase in reaction rate can allow for modification of how the three-vessel fluidized coking reaction system is operated. The resulting modification in operating conditions can allow for production of a modified and/or improved product slate from the fluidized coker. The modifications in the product slate can include an increase in total liquid products as well as a decrease in micro carbon residue and/or n-heptane insolubles in the total liquid products. Additionally, co-processing of biomass with a conventional/mineral coker feed can result in a total liquid product with an unexpected composition with regard to the types of components present within the total liquid product.

It is noted that the term “gasification” is used herein to broadly cover conversion of biomass to CO and/or Hin varying ratios of CO to H, including partial burn conditions that result in CO production with a reduced or minimized amount of Hproduction (such as substantially no Hproduction).

During operation of a three-vessel fluidized coking system, the center vessel corresponds to a “heater” vessel that provides several functions. First, the heater vessel facilitates heat transfer between the gasifier vessel and the reactor vessel. In the heater, hot coke from the gasifier mixes with cold coke from the reactor. This results in moderately heated particles that can then be returned in part to the reactor to provide heat for the endothermic coking reaction. Additionally, the gas phase products generated in the gasifier are returned at least in part to the heater as part of the fluidizing gas for transferring hot coke back to the heater. These gases then exit from the three-vessel fluidized coking system from a heater outlet, such as a heater overhead outlet.

The heater vessel, however, also places some constraints on the operating conditions for the three-vessel fluidized coking system. For example, one of the constraints on operation is the need to fully cure coke formed in the reactor vessel prior to transferring the coke particles to the heater vessel. The primary reaction in the coking reactor vessel is a pyrolysis reaction that can occur relatively quickly under a variety of conditions. However, the combination of a) reaction temperature and b) residence time for coke particles within the reactor vessel is typically higher in severity than is required for only performing the coking reaction. Instead, the residence time and temperature within the coking vessel are selected at a higher severity level to allow for additional reaction of the “hydrocarbon carry under” (HCCU). The HCCU corresponds to hydrocarbons (coke precursors) that are entrained with the coke particles as the coke particles exit from the reactor. Such entrainment can include entrainment within pores in the coke particles, or entrainment in the flow of coke particles. If these additional hydrocarbons are still at least partially in the fluid phase when they enter the heater, the increased temperature in the heater can volatilize these hydrocarbons. The volatilized hydrocarbons can then deposit in the overhead exit of the heater, resulting in fouling and thereby decreasing the operating lifetime between cleaning cycles.

To maintain longer operating lifetime between maintenance events, the coking reactor is operated at combinations of fluidized bed temperature and coke particle residence time that are higher in severity than is required for simply performing pyrolysis. This allows for additional reaction of the HCCU hydrocarbons. The additional reaction allows for additional pyrolysis of the HCCU hydrocarbons, so that the amount of potentially volatile hydrocarbons exiting from the reactor is reduced or minimized. However, this also means that additional pyrolysis occurs for substantially the entire feed in the coking reactor.

In various aspects, by co-processing a sufficient amount of biomass with a conventional resid feed, the reaction severity within the reactor can be reduced. It is noted that the impact of the biomass is catalytic in nature, so that at least a portion of the benefit can be realized even at relatively low amounts of biomass in the feed. This can allow for improvements in the resulting product slate from fluidized coking. First, the net amount of liquid product can be increased while reducing the production of light ends and coke. Second, even though the liquid product includes an increased amount of heavier liquids (such as heavy coker gas oil), the amount of micro carbon residue and/or n-heptane insoluble in the liquid product can be reduced or minimized. The reduction in micro carbon residue and/or n-heptane insolubles is accompanied by more general changes in the composition of the liquid product when co-processing biomass. It is noted that the benefits of reduction in micro carbon residue and/or n-heptane insolubles are realized when performing co-processing of biomass with a mineral feed that contains a sufficient amount of micro carbon residue and/or n-heptane insolubles. Thus, this benefit is typically realized when co-processing biomass with mineral feeds that include a substantial portion of components with a boiling point of 500° C. or above.

In some aspects, additional benefits from co-processing biomass with a mineral feedstock can be achieved for mineral feedstocks containing a sufficient amount of micro carbon residue (MCR) and/or n-heptane insolubles. In such aspects, a mineral portion of the feedstock for co-processing with biomass (such as a vacuum resid feedstock for co-processing) can have a micro carbon residue of 5.0 wt % or more, or 15 wt % or more, or 20 wt % or more, or 30 wt % or more, such as up to 50 wt % or possibly still higher. Additionally or alternately, a mineral portion of the feedstock for co-processing with biomass can have an n-heptane insolubles content of 5.0 wt % or more, or 10 wt % or more, or 15 wt % or more, or 20 wt % or more, or 30 wt % or more, such as up to 50 wt % or possibly still higher. After co-processing such a feedstock with biomass, the resulting total liquid product can have a micro carbon residue content of 0.5 wt % or less, or 0.2 wt % or less, or 0.1 wt % or less, such as down to substantially no micro carbon residue content (0.05 wt % or less). Additionally or alternately, after co-processing such a feedstock with biomass, the resulting total liquid product can have a content of n-heptane insolubles of 0.5 wt % or less, or 0.4 wt % or less, or 0.2 wt % or less, or 0.1 wt % or less, such as down to substantially no content of n-heptane insolubles (0.05 wt % or less). In contrast, typical coker liquid products (produces in the absence of a biomass co-feed) can contain 0.6 wt % or more, or 1.0 wt % or more, such as up to 5 wt % or more n-heptane insolubles or MCR.

In various aspects, the total liquid product can also have an unexpected content of oxygen and/or oxygenated components. In some aspects, the oxygen content of a co-processed total liquid product can be between 0.9 wt % to 3.0 wt %, or 0.9 wt % to 2.5 wt %. This is in contrast to a conventional total liquid product from processing of a mineral feed, which would be expected to have an oxygen content of less than 0.5 wt %. This is also different from a pyrolysis oil, which would be expected to have an oxygen content of well over 10 w1%. Additionally, it has been discovered that the oxygen content of a co-processed total liquid product is unexpectedly lower than the oxygen content that would be expected based on a weighted average of the feeds used for co-processing. The unexpected oxygen content also can be characterized based on the number of components/compounds in the total liquid product that include at least one oxygen atom. For a total liquid product from a conventional mineral feed, the content of oxygen-containing components would be expected to be less than 5.0 wt %. For a pyrolysis oil, more than 50 wt % of the compounds in the total liquid product would be expected to correspond to oxygen-containing components. By contrast, a co-processed total liquid product can contain between 10 wt % to 40 wt % of oxygen-containing components, or 10 wt % to 25 wt %, or 20 wt % to 40 wt %.

It is noted that the above benefits can be achieved while producing a total liquid product from co-processing of biomass and a mineral resid feedstock that includes 30 wt % to 50 wt % of naphtha boiling range components, 30 wt % to 50 wt % of heavy distillate boiling range components, 10 wt % to 25 wt % of light distillate boiling range components, and 5.0 wt % or less of vacuum resid boiling range components (such as down to substantially no vacuum resid boiling range components).

In addition to the above benefits related to an unexpected improvement in reaction rates within the coker reactor, a variety of additional features and/or benefits can be realized by using integrated pyrolysis and gasification to co-process biomass with a conventional feed for fluidized coking. One example of a benefit is a reduction in net greenhouse gas emissions. By integrating pyrolysis and gasification, the heat for pyrolysis can be provided by the heat generated during gasification. Because COwas consumed by the biomass during the growth of the biomass, any COgenerated from gasification of the biomass represents no net addition of COto the environment. In aspects where co-processing is performed, the reduction in net COproduction can be proportional to the amount of biomass char that is gasified relative to the amount of conventional feed that is gasified.

Another benefit or feature can be related to synergies between the gasification conditions and the pyrolysis processing conditions. In various aspects, the gasification conditions can be selected so that partial oxidation of char is performed in the gasifier. Any coke generated by co-processing of a conventional feed in the reactor can also be exposed to the partial oxidation conditions. Operating the gasifier under partial oxidation conditions can allow a synthesis gas product to be recovered from the gas phase products of the gasifier. The synthesis gas product can be used as a fuel, or the synthesis gas product can be used as an input flow for the production of additional liquid products.

In aspects where the gasifier is operated under partial oxidation conditions, so that an increased amount of CO is produced, the amount of heat generated per carbon atom introduced into the gasifier will be lower than the heat that would be generated by performing full oxidation and converting substantially all carbon into CO. Due to this reduction in heat generated by the gasifier, there is an increased likelihood that maximizing the production of liquids in the pyrolysis reactor may result in production of insufficient amounts of coke and/or char to maintain heat balance in the integrated system. For a conventional pyrolysis process, the goal is to select process conditions that maximize liquid yield. By contrast, in some aspects, instead of maximizing the ratio of liquid products to char that is generated during pyrolysis, the relative amount of char production can be increased so that additional char is provided to the gasification process. In such aspects, the increased char production can allow sufficient char to be delivered to the gasifier to maintain heat balance and/or can reduce or minimize the amount of additional biomass (or other fuel) that is added as a supplemental fuel to the gasifier.

In some aspects where integrated pyrolysis and gasification is performed, biomass can correspond to less than 50 wt % of the feed. In such aspects, the heat generated in the gasifier from partial oxidation can be sufficient to maintain heat balance while still operating at maximum liquid yield for the pyrolysis reaction. In other aspects, such as some aspects where biomass corresponds to 50 wt % to 60 wt % of the feed, the pyrolysis conditions can be selected to provide increased char production. Additionally or alternately, in some aspects where the char and/or coke generated during pyrolysis is not sufficient, additional biomass can be added to the gasifier in order to maintain heat balance.

In some aspects, additional particles can also be present in the reaction environment and/or can be added to the reaction environment. In a conventional fluidized coking process, coke particles are generated in the fluidized coking environment. The coke particles are partially gasified to provide heat, but the remaining mass of coke (in the form of particles) after the partial gasification can be sufficient to transport heat from the gasifier to the other reaction vessel(s) in the reaction system. However, in aspects where a sufficient amount of biomass is present in the feedstock, the mass of the char and/or coke that enters the gasifier may be relatively close to the amount of char and/or coke that is needed to maintain heat balance within the system. In such aspects, additional particles can be added to the system to act as a heat transfer particles, and to maintain the fluidized bed nature of the reaction environment in the reactor. In some aspects, relatively inert particles can be used, such as sand. In other aspects, at least a portion of the particles can correspond to a catalyst for catalyzing the pyrolysis reaction.

In this discussion, some feeds, fractions, or products may be described based on a fraction that boils below or above a specified distillation point. For example, a 343° C.− product corresponds to a product that substantially contains components with a boiling point (at standard temperature and pressure) of 343° C. or less. Similarly, a 343° C.+ product corresponds to a product that substantially contains components with a boiling point of 343° C. or more. Substantially containing components within a boiling range is defined herein as containing 90 vol % or more of components within the boiling range, optionally 95 vol % or more, such as a product where all components are within the specified boiling range.

In this discussion, a liquid product is defined as a product that is substantially in the liquid phase at 20° C. and ˜100 kPa-a. Similarly, a gas product is defined as a product that is substantially in the gas phase at 20° C. and ˜100 kPa-a.

In this discussion, reference may be made to conversion of a feedstock relative to a conversion temperature. Conversion relative to a temperature can be defined based on the portion of the feedstock that boils at greater than the conversion temperature. The amount of conversion during a process (or optionally across multiple processes) can correspond to the weight percentage of the feedstock converted from boiling above the conversion temperature to boiling below the conversion temperature. As an illustrative hypothetical example, consider a feedstock that includes 40 wt % of components that boil at 650° F. (˜343° C.) or greater. By definition, the remaining 60 wt % of the feedstock boils at less than 650° F. (˜343° C.). For such a feedstock, the amount of conversion relative to a conversion temperature of ˜343° C. would be based only on the 40 wt % that initially boils at ˜343° C. or greater. If such a feedstock could be exposed to a process with 30% conversion relative to a ˜343° C. conversion temperature, the resulting product would include 72 wt % of ˜343° C.− components and 28 wt % of ˜343° C.+ components.

As defined herein, the term “hydrocarbonaceous” includes compositions or fractions that contain hydrocarbons and hydrocarbon-like compounds that may contain heteroatoms typically found in petroleum or renewable oil fraction and/or that may be typically introduced during conventional processing of a petroleum fraction. Heteroatoms typically found in petroleum or renewable oil fractions include, but are not limited to, sulfur, nitrogen, phosphorous, and oxygen. Other types of atoms different from carbon and hydrogen that may be present in a hydrocarbonaceous fraction or composition can include alkali metals as well as trace transition metals (such as Ni, V, or Fe).

In this discussion, distillation points and/or distillation ranges can be determined according to ASTM D2887. In the event that a portion of a sample is not suitable for characterization using ASTM D2887, ASTM D7169 can be used instead.

In this discussion, the vacuum resid boiling range is defined as 538° C. and above. It is noted that it is difficult to characterize the end boiling point for some vacuum resid fractions, but the portions of vacuum resid that are susceptible to distillation can have an end point of up to roughly 750° C. It is further noted that fractions composed primarily of vacuum resid often contain substantial amounts of lower boiling components. In this discussion, a vacuum resid boiling range fraction is a fraction that has a T10 distillation point of 480° C. or higher (such as up to 600° C.).

In this discussion, the naphtha boiling range is defined as 29° C. to 221° C. The light distillate boiling range is defined as 221° C. to 343° C. It is noted that the light distillate boiling range could also be referred to as the diesel boiling range. The heavy distillate boiling range is defined as 343° C. to 538° C. It is noted that the heavy distillate boiling range could also be referred to as the vacuum gas oil boiling range.

Micro carbon residue can be determined according to ASTM D4530. The content of n-heptane insolubles in a sample can be determined according to ASTM D3279.

In various aspects, biomass can be co-processed in a fluidized bed coking environment. The biomass can be co-processed with a feedstock not derived from biomass, such as a mineral feedstock, and/or a feedstock having a boiling range corresponding to the conventional boiling range for a fluidized coking feed. In some aspects, the biomass can correspond to 1.0 wt % to 60 wt % of the feed for co-processing, or 1.0 wt % to 50 wt %, or 1.0 wt % to 35 wt %, or 10 wt % to 60 wt %, or 10 wt % to 50 wt %, or 10 wt % to 35 wt %, or 20 wt % to 60 wt % or 20 wt % to 50 wt %, or 30 wt % to 60 wt %, or 30 wt % to 50 wt %, or 50 wt % to 60 wt %.

The biomass used for a feed can be any convenient type of inedible lignocellulosic biomass; that is, biomass that is composed primarily of cellulose, hemicellulose, lignin, or a combination thereof. Some forms of biomass can include direct forms of biomass, such as algae biomass and plant biomass. Examples of suitable biomass sources can include woody biomass and switchgrass.

In aspects where the biomass is introduced into the fluidized coking reactor at least partially as solids, having a small particle size can facilitate transport of the solids into the reactor. Smaller particle size can potentially also contribute to achieving a desired level of conversion of the biomass. Thus, one or more optional physical processing steps can be used to prepare solid forms of biomass for conversion. To prepare solids for gasification, the solids can be crushed, chopped, ground, or otherwise physically processed to reduce the average particle size to 3.0 cm or less, or 2.5 cm or less, or 2.0 cm or less, or 1.0 cm or less, such as down to 0.001 cm or possibly still smaller. For determining an average particle size, the particle size is defined as the diameter of the smallest bounding sphere that contains the particle.

Without being bound by any particular theory, it is believed that oxygenated moieties derived from cellulose, lignin and hemicellulose within the biomass contribute to the improved reaction rate when co-processing a mineral feed. In various aspects, the biomass for co-processing can have a cellulose content of 10 wt % or more (relative to a weight of the biomass), or 20 wt % or more, or 30 wt % or more, such as up to using biomass that is substantially composed of cellulose (e.g., a cotton ball or other biomass that contains up to 100 wt % cellulose). In such aspects, the lignin content of the biomass can optionally be less than 35 wt %, or 30 wt % or less, such as down to having substantially no lignin content (1.0 wt % or less).

Biomass can be co-processed with one or more additional feedstocks, such as mineral feedstocks, based on the boiling range of the feed. The amount of the one or more additional feedstocks can correspond to 40 wt % to 99 wt % of the feed for co-processing, or 50 wt % to 99 wt %, or 65 wt % to 99 wt %, or 40 wt % to 90 wt %, or 50 wt % to 90 wt %, or 65 wt % to 90 wt %, or 40 wt % to 80 wt %, or 50 wt % to 80 wt %, or 40 wt % to 70 wt %. Conventionally, heavy oil feeds are typically used as feeds for fluidized coking processes. Thus, the heavy oil feed will typically be a heavy (high boiling) reduced petroleum crude; petroleum atmospheric distillation bottoms; petroleum vacuum distillation bottoms, or residuum; pitch; asphalt; bitumen; other heavy hydrocarbon residues; tar sand oil; shale oil; or even a coal slurry or coal liquefaction product such as coal liquefaction bottoms. Such feeds will typically have a Conradson Carbon Residue (ASTM D189-165) of at least 5 wt. %, generally from 5 to 50 wt. %. Preferably, the feed is a petroleum vacuum residuum. In some aspects, the one or more additional feedstocks can have a T10 distillation point (as determined according to ASTM D2887) 343° C. or higher, or 400° C. or higher, or 450° C. or higher, or 500° C. or higher, such as up to 600° C. or possibly still higher.

A typical petroleum (mineral) chargestock suitable for processing in a fluidized bed coker can have a composition and properties within the ranges set forth below.

It is noted that still other components can be included in a feed for co-processing in a fluidized coker. In some aspects, 20 wt % or less of a feed for co-processing can correspond to components that are a) not biomass and/or derived from biomass and b) have a boiling point below 340° C., such as down to having substantially no components of this type.

In various aspects, the improvement in reaction rates provided by co-processing lignocellulosic biomass under fluidized coking conditions can allow for changes in the target operating conditions for a feed, thereby allowing for production of a modified and/or improved product slate. This change is enabled in part by reducing the residence time required for full curing of coke precursors entrained in the coke exiting from the coker reactor vessel and passed into the heater vessel.

Hydrocarbon carry-under (HCCU) corresponds coke precursors that are not fully converted to a solid form prior to exiting from the coker reactor and entering the heater. Due to the higher temperatures in the heater, these coke precursors are volatilized and then deposit on cooler surfaces, such as the overhead exit from the heater. This results in coke formation in the overhead exit, eventually leading to constriction of the exit flow and requiring shut down to restore the flow path in the overhead exit to the original size. To avoid reduced length reaction cycles, the HCCU is maintained at a relatively low level by selecting sufficiently severe reaction conditions. In particular, relative to the average residence time for coke particles in the coker reactor vessel, higher temperatures are selected to maintain the HCCU at a sufficiently low level.

It has been discovered that co-processing of lignocellulosic biomass (that contains cellulose) in a fluidized coker can provide an increase in reaction rates within the coker reactor. This increase in reaction rates also increases the reaction rate for the curing process for coke precursors. Without being bound by any particular theory, it is believed that the increased reaction rates/increased curing rates are due to the creation of oxygen-containing radicals in the fluidized coking environment. It is believed that these oxygen radicals facilitate cracking of mineral portions of the feed within the fluidized coking environment. Additionally, it is believed that the oxygen radicals can also assist with conversion of some coke precursor compounds into compounds that instead form liquid products. Finally, it is believed that these oxygen radicals assist with the curing process for remaining coke precursors, so that HCCU is substantially reduced or minimized. As a result, the temperature in the fluidized bed of the coker reactor can be reduced while still maintaining a target level of HCCU. By reducing the temperature and/or based on the additional unexpected catalytic benefits of co-processing with biomass, a modified and/or improved product slate can be achieved.

The amount of HCCU during operation of a three-vessel fluidized coking system is typically maintained at a low level. In various aspects, by co-processing a mineral feedstock with biomass, the temperature and/or coke particle residence time in the coker reactor vessel can be reduced while still maintaining a low level of HCCU. In various aspects, the amount of HCCU during operation of a coker reactor vessel can correspond to 0.08 wt % of the input feed or less, or 0.06 wt % or less, such as down to having substantially no HCCU (0.005 wt % or less). The amount of HCCU can be characterized, for example, by sampling cold coke from the coke transfer line between the reactor and heater section of a commercial flexicoker during steady-state operations, and heat-treating the sampled material in an oxygen-free environment at temperatures that match those in the commercial unit's heater section. The wt % mass loss of volatilized material that is removed from the solid sample under these conditions corresponds to the HCCU.

The feed for co-processing can be introduced into the fluidized coking reactor by any convenient method. One option is to form a slurry and/or solution of biomass in a conventional feed. As another option, biomass can be introduced separately from the co-feed(s) as a feedstock composed primarily of solids. In this type of aspect, a feed mechanism for delivery of solids such as a screw feeder can be used. The feed can be pre-heated prior to entering the reactor. For example, in aspects where a conventional co-feed is used to form a slurry, pre-heating can increase the temperature of the feed so that it is flowable and pumpable. The slurry can then be passed into the reactor toward the top of the reactor vessel through one or more slurry injection nozzles.

In various aspects, temperatures in the fluidized coking zone of the reactor can be in the range of 400° C. to 550° C., or 400° C. to 500° C. Pressures can be in the range of 120 kPag to 400 kPag (17 psig to 58 psig), and preferably 200 kPag to 350 kPag (29 psig to 51 psig).

The conditions in the fluidized coking zone can be selected so that a desired amount of conversion of the feedstock occurs in the fluidized bed reactor. The coking reaction and the amount of conversion can be selected to be similar to the values used in a conventional fluidized coking reaction. For example, the conditions can be selected to achieve at least 10 wt % conversion relative to 343° C. (or 371° C.), or at least 20 wt % conversion relative to 343° C. (or 371° C.), or at least 40 wt % conversion relative to 343° C. (or 371° C.), such as up to 80 wt % conversion or possibly still higher. In some aspects, the light hydrocarbon products of the coking (thermal cracking) reactions vaporize, mix with the fluidizing steam and pass upwardly through the dense phase of the fluidized bed into a dilute phase zone above the dense fluidized bed of coke particles. It is noted that in some aspects, other sweep gases such as CH, H, or other light gases may be used instead of at least a portion of the steam (such as up to in place of substantially all of the steam) to help control the conversion severity. In some configurations, this mixture of vaporized hydrocarbon products formed in the coking reactions flows upwardly through the dilute phase with the steam at superficial velocities of ˜1 to 2 meters per second (˜3 to 6 feet per second), entraining some fine solid particles of coke which are separated from the cracking vapors in the reactor cyclones as described above. The cracked hydrocarbon vapors pass out of the cyclones into the scrubbing section of the reactor and then to product fractionation and recovery. The cracked hydrocarbon vapors can include one or more liquid products with a boiling range of 343° C. or less. Examples of 343° C.− liquid products include naphtha boiling range products and distillate boiling range products.

In some aspects, as the cracking process proceeds in the reactor, the coke, char, and/or other particles (such as optional sand particles) pass downwardly through the pyrolysis zone, through the stripping zone, where occluded hydrocarbons are stripped off by the ascending current of fluidizing gas (steam). They then exit the coking reactor and are passed into the heating vessel.

The heating vessel receives particles from both the coker reactor vessel and from the gasification vessel. Particles arriving from the coker reactor correspond to “cold” particles, while particles arriving from the gasification vessel correspond to “heated” particles. In the heater vessel, the particles mix resulting in transfer of heat from heated particles to cold particles. A portion of the particles are then sent to the coker reactor, while another portion of the particles are sent to the gasification reactor for further heating. A remaining portion of the particles can be withdrawn from the heater vessel. The removal of particles from the heater vessel provides a mechanism for avoiding the build-up of metals within the fluidized coking system.

The combustion/oxidation products generated in the gasifier (such as synthesis gas components formed during partial oxidation) can serve as a fluidizing gas in the heater for mixing the particles.