High pressure scheme with low-pressure slurry stripper

Abstract

Provided is a process for optimizing throughput and flash during the hydroconversion of circular and renewable feed stocks into renewable fuel comprising the use of a slurry reactor. The present process uses high pressure operation of a vaporization stage in combination with the use of low-pressure stripping segments. The inclusion of low-pressure stripping segments allows the reactor to operate at high pressure, reducing CAPEX and OPEX, without the associated issues with flash and throughput commonly observed.

Description

Atorney Docket No. 70205.0709WOU1 (T- 12541 -WOO 1)HIGH PRESSURE SCHEME WITH LOW-PRESSURE SLURRY STRIPPERCROSS-REFERENCE TO THE RELATED APPLICATION

[0001] This application claims the benefit of U. S. Provisional Patent Application No. 63 / 723,671, filed November 22, 2024, the disclosure of which is hereby incorporated in its entirety.TECHINCAL FIELD

[0002] The present process relates to using a slurry reactor to hydroconvert lipid into a renewable fuel. The process employs a modified high pressure scheme.BACKGROUND

[0003] Renewable fuels, a sustainable alternative to traditional fossil fuels, are becoming increasingly important. Traditional fossil fuels are not only limited in quantity but contribute significantly to carbon emissions, a driver of climate change. Despite global initiatives to curtail carbon emissions, fossil fuel dependence remains pervasive, making sustainable fuel alternatives increasingly relevant. This relevance has been matched by a rise in production of renewable fuels. Lipids such as vegetable oils and animal fats represent one common feedstock for renewable fuel. These feedstocks can be converted into renewable fuels using a slurry reactor. However, converting feedstocks in this manner presents serious challenges. Namely, the separation of the renewable fuel product from the slurry catalyst.

[0004] hi slurry operation, the final desired product must be separated from the slurry catalyst, which is suspended in the product. Gas or mechanical agitation is often used to effect the separation. Separation most often occurs using vaporization, an economic and reliable method of product separation. However, critical to the vaporization stage is the management of the throughput and capacity of the feedstock through the vaporizer. Managing the throughput and capacity presents its own challenges and largely depends on two factors. First, reaction, wherein high boiling point feed is converted into low boiling point product. And second, flash, wherein the low boiling point product vaporizes into a vapor phase. In most cases, the throughput and capacity of this vaporization stage is limited by flash, as reaction occurs much faster.Atorney Docket No. 70205.0709WGU1 (T- 12541 -WOO 1)

[0005] Another important consideration of the vaporization stage is the operating pressure. High pressure operation during the vaporization stage offers several benefits. Higher operating pressures promote reaction kinetics, leading to a higher rate, conversion, and better / different yield. Operating at a high pressure also allows the use of a smaller reactor, gas compression, etc. These characteristic features of high- pressure operation reduce the capital and operation expenditure of the entire system.

[0006] Yet despite these many desirable qualities, high pressure operation comes with its own challenges. High pressure has been known to lower flash, even at the same gas feed rate. Additionally, lower pressure environments are better suited for the vaporization and removal of products with low boiling points. Thus, high-pressure environments can lower throughput due to these products remaining in the reactor, introducing capacity issues. The detriment to throughput and flash caused by high pressure operation can introduce bottlenecking to the entire operation. The bottlenecking caused by high pressure operation of vaporization stage, if managed improperly, will eliminate any benefits of combining the two methods.

[0007] Thus, a new and efficient method of managing throughput and flash bottlenecking when combining vaporization and high-pressure operation would be extremely desirable and beneficial to the industry.SUMMARY

[0008] Provided is a process for optimizing throughput and flash during the hydroconversion of circular and renewable feedstocks into renewable fuel comprising the use of a slurry reactor. One embodiment the present process can permit high pressure operation of the vaporization stage with the use of low-pressure stripping segments. Use of low-pressure stripping segments have, surprisingly been shown to achieve the same or even higher levels of flash and product vaporization. The inclusion of low-pressure stripping segments allows the reactor to operate at high pressure, reducing CAPEX & OPEX, without the associated issues with flash and throughput described above. This, consequently, improves reactor capacity. The associated economic and operational benefits permit for the efficient conversion of circular and renewable feedstocks into sustainable liquid product. The use of the present process offers significant economic and environmental benefits if adopted by the industry.Atorney Docket No. 70205.0709WGU1 (T- 12541 -WOO 1)BRIEF DESCRIPTION OF THE FIGURES

[0009] FIG. 1 depicts a flow diagram of the typical practice of vaporization comprising the use of a slurry reactor.

[0010] FIG. 2 depicts a flow diagram of one embodiment of the present process for optimizing throughput and flash during the hydroconversion of circular and renewable feedstocks into renewable fuel comprising the use of a slurry reactor system comprising a low-pressure stripping segment.DETAILED DESCRIPTION

[0011] Before the process for a novel method for optimizing throughput and flash during the hydroconversion of circular and renewable feedstocks into renewable fuel comprising the use of a slurry reactor is disclosed and described, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a step” may include multiple steps, reference to “producing” or “products” of a reaction or treatment should not be taken to be all of the products of a reaction / treatment, and reference to “treating” may include reference to one or more of such treatment steps. As such, the step of treating can include multiple or repeated treatment of similar materials / streams to produce identified treatment products,

[0012] Numerical values with “about” include typical experimental variances. As used herein, the term “about” means within a statistically meaningful range of a value, such as a stated particle size, concentration range, time frame, molecular weight, temperature, or pH. Such a range can be within an order of magnitude, typically within 10%, and more typically within 5% of the indicated value or range. Sometimes, such a range can be within the experimental error typical of standard methods used for the measurement and / or determination of a given value or range. The allowable variation encompassed by the term “about” will depend upon the particular system under study, and can be readily appreciated by one of ordinary skill in the art. Whenever a range isAtorney Docket No. 70205.0709WQU1 (T- 12541 -WOO 1)recited within this application, every whole number integer within the range is also contemplated as an embodiment of the invention.

[0013] One embodiment of the present process comprises a novel method for optimizing throughput and flash during the hydroconversion of circular and renewable feedstocks into renewable fuel comprising the use of a slurry reactor. In one embodiment the present process the high-pressure operation of the vaporization stage comprises the use of low-pressure stripping segments. Use of low-pressure stripping segments have, surprisingly, been shown to achieve the same or even higher levels of flash and product vaporization as low and high-pressure operation. The inclusion of low-pressure stripping segments allows the reactor to operate at high pressure, reducing CAPEX & OPEX, while maintaining the same or higher throughput as low pressure operation. The increase in throughput, consequently, improves reactor capacity.

[0014] In typical slurry reactor operation, the slurry unit is run at a low pressure (less than 800-1200 psig). Slurry reactors require separation of the slurry catalyst from the effluent stream. The separation of the slurry catalyst from the effluent can be done either in separative reactor (distillation reactor, evaporative reactor) or in HHPS (hot high-pressure separator) while the reactor is liquid / slurry filled. The effluent from the separative reactor or HHPS is separated into two steams, wherein the light product is fed to a MTHPS (Middle-Temperature High-Pressure Separator) while the heavy product is fed to a HTMPS (High-Temperature Middle-Pressure Separator). The MTHPS effluent is further separated into gas, and a liquid product, while the HTMPS effluent is separated into a liquid product and a slurry bleed. The liquid product is considered a heavy stream of the HTMPS and accounts for roughly 83% of the product feed flow. A light stream of the HTMPS accounts for roughly <1% of the product feed flow. The liquid product can then be sent to a fluidized bed reactor for further hydroprocessing.

[0015] However, when this system is operated at high pressure (-1900 psig), sufficient separation cannot be achieved in a separative reactor and / or HHPS anymore. This is because high pressure has been known to lower flash, even at same gas feed rate. Additionally, lower pressure environments are better suited for the vaporization and removal of products with low boiling points. Thus, high-pressure environments result in lower throughput due to these products remaining in the reactor, introducing capacity issues. The detriment to throughput and flash caused by high pressure operation can introduce bottlenecking to the entire operation.Atorney Docket No. 70205.0709WQU1 (T- 12541 -WOO 1)

[0016] In one embodiment of the present process, vaporization can still be accomplished with a HHPS, by introducing a low-pressure slurry stripper, which can be added to complete the evaporation of product. The effluent from the separative reactor or HHPS can be separated into two streams, wherein the light product is fed to a MTHPS while the heavy product can be fed to a HTMP (high temperature middle pressure) - Stripper. The operating conditions for the HTMP-Stripper may comprise an operating temperature of 650°F, and an operating pressure of 200 psig. In one embodiment about half of the product can removed at HHPS, while the other half can be stripped at the HTMP-stripper. The MTHPS effluent can be further separated into gas, and a liquid product, while the HTMP-Stripper effluent is separated into liquid product, recycle stream, and a slurry bleed. Liquid product is considered a heavy stream of the MTHPS and can account for roughly 43% of the product feed flow, and a light stream of the HTMP-Stripper which can account for roughly 40% of the product feed flow. The liquid product can then be sent to a fluidized bed reactor for further hydroprocessing. This process scheme may be used for renewable and circular feeds, such as lipid feeds, when products are mainly in distillate range, e.g., with boiling point less than 360°C / 680°F.

[0017] In one embodiment the recycle steam from an LP stripper can be used to maintain a high level of catalyst in the reactor. In one embodiment this can be accomplished by mixing the bottom of the slurry stripper with fresh feed which can be pumped into the reactor. In another embodiment this can be accomplished using a dedicated recycle pump. In one embodiment the recycle stream can be at least 20% of fresh feed to the reactor. In another embodiment the recycle stream can be at least 40% of fresh feed to the reactor. The addition of a recycle stream to the slurry reactor is extremely advantageous. Maintaining a high level of catalyst in the slurry reactor is essential for reaction, as the reaction is mainly catalytic. In one embodiment said recycle stream can comprise a solid / catalytic content of up to 60 wt%. The solid / catalytic content of the recycle stream can be limited by flowability. Thus, the LP stripper not only improves the flash and throughput of the system but also improves the catalytic activity of the slurry reactor. Advantageously, the spent catalyst bleed from this system also remains the same for both high and low-pressure operation. This allows low pressure stripping, which can vaporize products with a high boiling point better than high-pressure stripping. Low-pressure stripping also provides the benefit of flexibility within operation, as changing the stripping gas rate will adjust the extent ofAtorney Docket No. 70205.0709WOU1 (T- 12541 -WOO 1)vaporization. Said stripping gas may comprise any inert gas, for example, steam, hydrogen, nitrogen. In one embodiment, steam is preferred due to its low cost. In one embodiment, the feedstock for the slurry reactor can be a lipid feedstock. Thus, operation of the system comprising the use of a low-pressure slurry stripper offers a plurality of benefits.

[0018] In one embodim ent, 80% of the liquid product from this embodiment has a boiling point of 680°F. In another embodiment, at least 70% of the liquid product has a boiling point of 680°F. In another embodiment, the liquid product has a boiling point slightly above 680°F.

[0019] Now, referring to the figures of the drawings, FIG. 1 depicts a current practice of vaporization using low pressure. A slurry reactor 1000 is fed with fresh slurry catalyst 1001 and hydrogen 1002. The reactor effluent 1003 is passed to a HHPS 1004, where the feed is separated into a light fraction 1005 and a heavy fraction 1006. The light fraction 1005 is passed to an MTHPS 1007 where it is further separated into gas 1008 and liquid product 1009. The heavy fraction 1006 is passed to HTMPS 1010 where it is further separated into liquid product 1011 and a slurry bleed 1012. Slurry bleed 1012 can be passed to a low-pressure separator or filter, while liquid product 1011 is mixed with liquid product 1009. The mixed liquid product can then be sent to a fixed bed reactor.

[0020] FIG. 2 depicts one embodiment of the present process. A slurry reactor 2000 is fed with fresh slurry catalyst 2001 and hydrogen 2002. The reactor effluent 2003 is passed to a HHPS 2004, where the feed is separated into a light fraction 2005 and a heavy fraction 2006. The light fraction 2005 is passed to an MTHPS 2007 where it is further separated into gas 2008 and liquid product 2009. The heavy fraction 2006 is passed to HTMP-Stripper 2010 where it is further separated into liquid product 2011 and a slurry bleed 2012. Slurry bleed 2012 can be passed to a low-pressure separator or filter, or to a recycle stream 2013. Liquid product 2011 is mixed with liquid product 2009. The mixed liquid product can then be sent to a fixed bed reactor.Process Testing and Results

[0021] A test of the current process was conducted. Case 1 depicts a process according to the embodiment of FIG. 1 at an operating pressure of 1000 psig. Case 2 depicts a process according to the embodiment of FIG. 1 at an operating pressure of 1900 psig. Case 3 depicts a process according to the embodiment of FIG. 2 at anAtorney Docket No. 70205.0709WGU1 (T- 12541 -WOO 1)operating pressure of 1900 psig. Important is the distinction between case 1 and case 2. Both cases were carried out at different operating pressure, and Table 1 depicts a significantly lower LHSV when using the higher operating pressure. However, as seen in Table 1, Case 3 has a LHSV of 0.8 - 1.6hr-1. This LHSV is at least the same as Case 2 but can be higher than the LHSV of case 1. Importantly, the LHSV outperforms low pressure operation while operating at a high pressure.TABLE 1Feed Refined Soybean Oil Catalyst Same for eachCase 1 2 3LP Stripping No No Yes Temperature, °F 700 700 700 Reactor Pressure. Psig 1000 1900 1900 LHSV, hr-1 1.45 0.81 0.80 -1.6 Oxygen Removal 98% or higher 98% or higher 98% or higher Data SourceReactor Pilot Plant Pilot Plant Pilot Plant HP Separation Pilot Plant Pilot Plant Pilot Plant LP Stripping Pilot Plant Pilot Plant PROII Simulation

[0022] As used in this disclosure the word “comprises” or “comprising” is intended as an open-ended transition meaning the inclusion of the named elements, but not necessarily excluding other unnamed elements. The phrase “consists essentially of’ or “consisting essentially of’ is intended to mean the exclusion of other elements of any essential significance to the composition. The phrase “consisting of’ or “consists of’ is intended as a transition meaning the exclusion of all but the recited elements except for only minor traces of impurities.

[0023] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numericalAtorney Docket No. 70205.0709WQU1 (T- 12541 -WOO 1)parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained.

[0024] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the technology are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0025] It will be clear that the compositions and methods described herein are well adapted to attain the ends and advantages mentioned as well as those inherent therein. Those skilled in the art will recognize that the methods and systems within this specification may be implemented in many manners and as such are not to be limited by the foregoing exemplified embodiments and examples. In this regard, any number of the features of the different embodiments described herein may be combined into one single embodiment and alternate embodiments having fewer than or more than all of the features herein described are possible.

[0026] As those skilled in the art will appreciate, numerous modifications and variations of the present invention are possible considering these teachings, and all such are contemplated hereby. For example, in addition to the embodiments described herein, the present invention contemplates and claims those inventions resulting from the combination of features of the invention cited herein and those of the cited prior art references which complement the features of the present invention. Similarly, it will be appreciated that any described material, feature, or article may be used in combination with any other material, feature, or article, and such combinations are considered within the scope of this invention.

[0027] All of the publications cited in this disclosure are incorporated by reference herein in their entireties for all purposes.

Claims

Atorney Docket No. 70205.0709WOU1 (T- 12541 -WOO 1)What is claimed is:

1. A process comprising:conducting a hydroconversion reaction in a slurry reactor;recovering a product from the reactor and passing the product to a hot high- pressure separator (HHPS) unit;dividing the product into two streams with one stream passed to a high temperature middle-pressure (HTMP) stripper and the other to a middle temperature high-pressure separator (MTHPS) unit.

2. The process of claim 1, wherein the pressure in the slurry reactor is a least 1900 psig.

3. The process of claim 2, wherein the temperature in the slurry reactor is at least 700°F.

4. The process of claim 1, wherein about 80% of the HHPS unit product is passed to the HTMP stripper unit.

5. The process of claims 1 and 4, wherein the temperature in the HTMP stripper to 650°F and the pressure about 200 psig.

6. The process of claim 1, wherein a heavy liquid product from the MTHPS unit is recovered and a light stream product from the HTMP stripper is recovered, with at least part of the two products combined.

7. The process of claim 1, wherein a bottom product from the HTMP stripper is recycled to the slurry reactor.

8. The process of claim 1, wherein the hydroconversion is of circular or renewable feedstocks.

9. The process of claim 6, wherein the liquid product is a renewable fuel.Atorney Docket No. 70205.0709WOU1 (T- 12541 -WOO 1)10. The process of claim 1, wherein the stream passed to the HTMP stripper is the heavier of the two streams.

11. The process of claim 1, wherein the stream passed to the MTHPS is the lighter of the two streams.

12. The process of claim 1, wherein liquid products are recovered from the HTMP stripper and the MTHPS unit, with the liquid products then mixed to prepare a mixed liquid product.

13. The process of claim 12, wherein the mixed liquid product is passed to a fixed bed reactor.

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