Process and apparatus for producing ethylene from alcohol

Abstract

A novel process and apparatus for ethanol dehydration combines a furnace with a dehydration reactor in a single vessel. The reactor contains catalyst tubes within a firebox. Catalyst may be added to and removed from the catalyst tubes. The apparatus significantly reduces the capital cost of the apparatus while maintaining isothermal conditions for the reaction.

Description

[Technical Field]

[0001] (Statement of priority) This application claims priority to U.S. Provisional Patent Application No. 63 / 477,387, filed December 28, 2022, the entire contents of which are incorporated herein by reference.

[0002] The field is the conversion of alcohols to olefins. The field may particularly relate to the dehydration of ethanol to produce ethylene and the subsequent conversion of ethylene to long-chain olefins, and the hydrogenation of the long-chain olefins to produce paraffins. [Background technology]

[0003] Oil and gas refiners worldwide are exploring methodologies and pathways to reduce their carbon footprint in more sustainable processes. The ethanol-to-jet fuel process is one promising pathway to minimize or reduce net carbon dioxide combustion. The end product of this process is jet fuel and diesel fuel produced from bioethanol. Jet fuel is a sustainable aviation fuel intended to replace jet fuel produced from traditional sources such as crude oil.

[0004] The process of converting ethanol into jet fuel involves three main steps: the first step is to dehydrate the ethanol to produce ethylene, the second step is to convert the ethylene to long-chain olefins, and the second step is to hydrogenate the long-chain olefins to produce paraffins.

[0005] The ethanol dehydration process involves dehydrating ethanol molecules to create ethylene and water. The process of converting ethanol to ethylene is endothermic in nature, and the heat of the endothermic reaction is typically provided by a furnace, which is adiabatic in nature. Adiabatic reactor systems can have drawbacks, such as selectivity to undesired products, potential underutilization of catalyst, higher utility consumption, and larger footprint.

[0006] An improved reactor for dehydrating ethanol to ethylene is desirable. Summary of the Invention

[0007] The present inventors have discovered a novel process and apparatus for ethanol dehydration that combines a heated furnace with a dehydration reactor in a single vessel. The reactor contains catalyst tubes within a firebox. Catalyst may be added to and removed from the catalyst tubes. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic process flow diagram of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of a reactor of the present disclosure. [Figure 3] FIG. 3 is a partial view of FIG. 2 showing an additional embodiment of the present disclosure.

[0009] definition The term "communication" means functionally allowing the flow of materials between the listed components.

[0010] The term "downstream communication" means that in downstream communication, at least a portion of the material flowing to the subject is functionally capable of flowing from the object from which it is communicated.

[0011] The term "upstream communication" means that at least a portion of the material flowing from the component of interest in the upstream communication is functionally capable of flowing to the component from which it is communicated.

[0012] The term "direct communication" means that a stream from an upstream component enters a downstream component without passing through a fractionation or conversion unit and undergoing a change in composition by physical fractionation or chemical conversion.

[0013] The term "indirect communication" means that a stream from an upstream component passes through a fractionation or conversion unit and undergoes a change in composition by physical fractionation or chemical conversion before entering a downstream component.

[0014] The term "bypass" means that the source of communication is out of downstream communication with the bypass target, at least to the extent that it bypasses.

[0015] The term "column" refers to a distillation column or columns for separating one or more components of different volatility. Unless otherwise indicated, each column includes a condenser at the top of the column for condensing and refluxing a portion of the overhead stream that returns to the top of the column, and a reboiler at the bottom of the column for vaporizing a portion of the bottom stream and returning it to the bottom of the column. The feed to a column may be preheated. The top pressure is the pressure of the overhead vapor at the vapor outlet of the column. The bottom temperature is the liquid bottom outlet temperature. The overhead and bottom lines refer to the net lines from the column to the column downstream of any reflux or reboil. A stripper column may omit the reboiler at the bottom of the column and instead provide the heating requirements and driving force for separation from a fluidized inert medium such as steam. A stripping column typically feeds the feed to the top tray and removes the main product from the bottom.

[0016] As used herein, the term "component-rich stream" means that the rich stream exiting the vessel has a higher concentration of the component than the feed to the vessel.

[0017] As used herein, the term "component lean stream" means that the lean stream exiting the vessel has a lower concentration of the component than the feedstock to the vessel.

[0018] As used herein, the term "separator" means a vessel having an inlet and at least an overhead vapor outlet and a bottoms liquid outlet, and may also have an aqueous outlet from a boot. A flash drum is a type of separator that may be in downstream communication with a separator that may be operated at a higher pressure.

[0019] As used herein, the term "predominant" or "predominantly" means more than 50%, suitably more than 75%, and preferably more than 90%.

[0020] As used herein, "C x " should be understood to refer to a molecule having the number of carbon atoms represented by the "x" subscript. x The term "-" refers to a molecule containing less than or equal to x, preferably x and less, carbon atoms. x The term "+" refers to a molecule having more than or equal to x, preferably x and more, carbon atoms.

[0021] As used herein, the term "carbon number" refers to the number of carbon atoms per hydrocarbon molecule, typically a paraffin molecule. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1 illustrates a process and apparatus 10 for dehydrating an oxygenate feedstock according to one exemplary embodiment. The oxygenate feedstock may include an alcohol, preferably ethanol. The feedstock may include ethanol as a primary component and may be aqueous. Preferably, the oxygenate feedstock is a biorenewable feedstock.

[0023] Feed line 12 transports the oxygenate stream of the oxygenate feedstock to feed pretreatment section 14. Feed pretreatment section 14 includes vessel 16 containing a bed of cation exchange resin adsorbent for removing metal contaminants, such as sodium, zinc, phosphate, copper, and calcium, from the oxygenate stream in feed line 12. The adsorbent may be Amberlyst 15, available from DuPont. Feed pretreatment section 14 may include an additional vessel 18 containing a bed of the same adsorbent for further removal of metals from the oxygenate stream. Vessels 16, 18 may be in a series or lead-lag configuration to allow for regeneration of spent adsorbent. Line 17 transports the partially pretreated oxygenate stream from the outlet of vessel 16 to the inlet of vessel 18. The pretreated oxygenate stream exits feed pretreatment section 14 from the outlet of additional vessel 18 in line 20 and is fed to purification column 22. Feed pretreatment section 14 may be operated at temperatures between 32°C (90°F) and 104°C (220°F) and atmospheric pressure of 696 kPa (gauge) (100 psig).

[0024] In refinery column 22, the pretreated oxygenate stream is fractionated to separate ethanol from heavier oxygenates, also known as fusel oils, such as cyclohexanol, cyclopentanol, and heavier acids. Refinery column 22 is operated to minimize ethanol to no more than 1% of the feed in the bottoms stream in line 26. A heavy oxygenate stream in bottoms line 26 is removed from the bottom of refinery column 22 and sent to heavy oxygenate processing. Refinery column 22 may be reboiled by heat exchange with a suitable hot stream, such as steam, to provide the heat necessary for distillation. Refinery column 22 provides an overhead gas stream of purified ethanol in overhead line 24 that may be cooled in air cooler 25 and fed to feed surge drum 26 along with a recycled ethanol stream in line 27. Purification column 22 may be operated at a bottom temperature of between 82°C (180°F) and 121°C (250°F) and an overhead pressure of between 35 kPa (gauge) (5 psig) and 140 kPa (gauge) (20 psig).

[0025] In the feed surge drum 26, the ethanol may be blanketed with nitrogen. A charge pump 29 pumps an ethanol charge stream in line 28. The ethanol charge stream in line 28 is heat exchanged with a dehydration exchange stream in line 32, mixed with steam in line 33, and fed to a dehydration reactor 34 in charge line 35. In the dehydration reactor 34, the ethanol charge stream in line 28 is fed to a plurality of catalyst tubes 36 containing a dehydration catalyst. The catalyst tubes 36 are disposed within a firebox 38 in which a fuel stream from a fuel line 40 is combusted to provide heat to supply enthalpy for the endothermic dehydration reaction. In the dehydration reactor 34, the ethanol feed is converted to ethylene and water over the dehydration catalyst in the catalyst tubes 36 at temperatures between 400°C and 550°C and pressures between 455 kPa (gauge) and 65 psig (90 psig). The dehydrated stream exits the dehydration reactor 34 in effluent line 32. The dehydration catalyst is an alumina-based catalyst.

[0026] The dehydrated stream in line 32 exchanges heat with the charge stream in line 30 to provide a cooled dehydrated stream in line 64. The cooled dehydrated stream in line 64 is fed to a quench tower 68 where it is quenched by direct contact with water from a first cooling water stream in line 70 and a second cooling water stream in line 72. A quenched ethylene stream is discharged through quench tower overhead line 74, and a bottoms stream is discharged at the bottom of the tower in line 76. The bottoms stream is split into a drain stream in line 78 which can be transported through a valve thereon to a waste water stripper column 80, and a quench recycle stream in line 82. A first portion of the quench recycle stream is air cooled in product condenser 69 and recycled through a valve thereon as a first cooler cooled water stream in line 70, and a second portion of the quench recycle stream is heat exchanged in trim condenser 71 and recycled to quench tower 68 as a second warmer cooled water stream in line 72. Quench tower 68 may be operated at a bottom temperature between 37°C (100°F) and 104°C (220°F) and an overhead pressure between 280 kPa (gauge) (40 psig) and 490 kPa (gauge) (70 psig).

[0027] The quenched ethylene stream in line 74 is fed to first-stage suction drum 86. In the first-stage suction drum, ethylene exits overhead line 88 to first-stage compressor 90, while residual water exits the bottom of the drum in line 92 through a control valve thereon and is transported to wastewater stripper column 80, possibly via line 78. First-stage compressor 90 compresses the ethylene stream to a first pressure of 350 kPa (gauge) (50 psig) to 1225 kPa (gauge) (175 psig), and the effluent in line 91 is cooled in first-stage effluent cooler 93 and first-stage trim cooler 94.

[0028] The cooled, compressed ethylene stream from first-stage trim cooler 94 is fed to first-stage discharge drum 96. From first-stage discharge drum 96, ethylene exits overhead line 98 to second-stage compressor 100, while residual water exits the bottom of the drum in line 102 through a control valve thereon and is transported to wastewater stripper column 80, possibly via lines 92 and 78. The second-stage compressor compresses the ethylene stream to a second pressure of 455 kPa (gauge) (165 psig) to 3220 kPa (gauge) (460 psig), and the discharge in line 101 is cooled in second-stage discharge cooler 103 and second-stage trim cooler 104.

[0029] The twice-cooled, compressed ethylene stream from second-stage trim cooler 104 is fed to second-stage discharge drum 106. From second-stage discharge drum 106, ethylene exits overhead line 108 and is transported to water wash column 110, while a residual water stream exits the bottom of the drum in line 112 through a control valve thereon and is transported to wastewater stripper column 80, possibly via lines 102, 92, and 78.

[0030] In water wash tower 110, the twice-cooled and compressed ethylene stream is washed countercurrently with cooled, treated water in line 118 from wastewater stripper column 80 to absorb additional oxygenates and produce a washed ethylene stream discharged in overhead line 120 and a wash water stream discharged in bottoms line 122. The washed ethylene stream in overhead line 120 is transported to caustic scrubber column 116. The wash water stream in line 122 is returned to wastewater stripper column 80 through a valve thereon. Water wash tower 110 can be operated at a bottoms temperature of 16°C (60°F) to 82°C (150°F) and an overhead pressure of 2800 kPa (gauge) (400 psig) to 3500 kPa (gauge) (500 psig).

[0031] Caustic scrubber column 116 has a lower caustic wash section 124 and an upper water wash section 132. In lower caustic wash section 124, the washed ethylene stream in line 120 is scrubbed with an aqueous caustic stream from line 126 to absorb acid gases, such as carbon dioxide, from the washed ethylene stream. Spent caustic is pumped from the bottom of the lower section in line 128 and replenished with fresh caustic in line 130 to provide aqueous caustic stream 126. The scrubbed vapor ethylene stream, with acid gases removed, ascends from caustic wash section 124 through a steam inlet to upper water wash section 132. In water wash section 132, the scrubbed ethylene stream is contacted with a wash water stream from line 134. The washed, scrubbed vapor ethylene stream exits the top of water wash section 132 in line 136 and is fed to product dryer section 140. A spent water stream is removed in line 142 from a liquid sump at the bottom of water wash section 132 and is supplemented with a fresh water stream from line 144 to provide a wash water stream in line 134 which is pumped to the top of water wash section 132 for contact with the scrubbed vapor ethylene stream. The caustic scrubber column may be operated at a bottom temperature of 38°C (100°F) to 43°C (110°F) and an overhead pressure of 2800 kPa (gauge) (400 psig) to 2975 kPa (gauge) (425 psig).

[0032] In product dryer section 140, the washed and scrubbed ethylene stream in line 136 is fed to a first dryer inlet knockout drum 146 to remove residual water and provide a dryer inlet stream in line 148 and a knockout water stream in bottoms line 150, which is possibly fed to wastewater stripper column 80 via line 122. The dryer inlet stream is fed in line 148 to a first product dryer 152. First product dryer 152 contains an adsorbent for adsorbing water from the ethylene in the dryer inlet stream in line 148 to provide a dried ethylene stream. The adsorbent may be a molecular sieve material having a pore size of 2 to 4 Å. First product dryer 152 may be operated in an upflow mode. Product dryer section 140 may include a second product dryer 156 operating as first product dryer 142. The two product dryers may be operated in series, but are preferably arranged in lead-lag operation to facilitate regeneration during continuous operation. Second product dryer 156, like first product dryer 152, includes an adsorbent for adsorbing water from the ethylene. A dry ethylene stream exits product dryer section 140 as a dry ethylene stream in line 158. Product dryer section 140 may be operated at a temperature between 32°C (90°F) and 49°C (120°F) and a pressure between 2.8 MPa (gauge) (400 psig) and 3.1 MPa (gauge) (450 psig).

[0033] The dried ethylene stream in line 158 is fed to a dryer outlet knockout drum 160 to remove residual water and provide a dryer outlet stream in line 162 and a second knockout water stream in a bottoms line 164 which is possibly fed to wastewater stripper column 80 via lines 150 and 122.

[0034] The dryer effluent stream in line 162 may be fed to a heavy oxygenate removal column 170 to separate an overhead stream containing primarily ethylene, but possibly higher olefins, from heavy ketones and diethyl ether. Olefins are produced in overhead line 172 and fed to a third-stage compressor 174, and a bottom heavy oxygenate stream is produced in bottoms line 176. A heavy oxygenate purge stream may be taken to heavy oxygenate processing in line 178, while the reboiled portion is reboiled and returned to column 170. An ethylene stream compressed at a pressure of 2800 kPa (gauge) (400 psig) to 7000 kPa (gauge) (1000 psig) in compressor discharge line 176 may be provided to the dimerization section. Heavy oxygenates removal column 170 may be operated at a bottom temperature of −29° C. (−20° F.) to 121° C. (250° F.) and an overhead pressure of 2.4 MPa (gauge) (350 psig) to 3.1 MPa (gauge) (450 psig).

[0035] The water streams containing oxygenates and volatiles in lines 92, 102, 112, 122, 150, and 164 may be fed to wastewater stripper column 80, where the volatiles and oxygenates are boiled off to provide an overhead volatiles stream in line 182 and a stripped water stream in line 184. A portion of the stripped water stream may be reboiled and returned to the column to provide the necessary heat. The treated water stream in line 186 may be pumped to a water outlet, including another water outlet in line 188, and the cooled, treated water stream in line 118 may be sent to water wash tower 110. Wastewater stripper column 80 may be operated at a bottom temperature of 93°C (200°F) to 121°C (250°F) and an overhead pressure of 35 kPa (gauge) to 138 kPa (gauge) (20 psig).

[0036] The overhead volatiles stream in line 182 may be cooled in air cooler 189 and fed to off-gas knockout drum 190. The overhead stream from knockout drum 190 in line 192 may be sent to a flare, while the ethanol recycle stream is pumped to feed surge drum 26 in line 27, possibly via line 24.

[0037] The dehydration reactor 34 is shown in detail in FIG. 2. An ethanol charge stream in line 35 supplies heated ethanol to a reactor inlet 37. A temperature indicator controller (TIC) may be located on line 35 to measure the temperature of the ethanol charge stream. The distribution inlet 37 supplies ethanol to a distribution header 39 via a screen port 41. The distribution header 39 may be a pipe grid or may comprise a cylindrical or rectangular box with a tube plate fitted to the catalyst tubes 36. However, the distribution header has distribution openings 39o that are continuous with the catalyst tube inlets 36i to the corresponding catalyst tubes 36. The distribution openings 39o may be fitted to the distribution header 39 by mating flange connections (not shown). Additionally, mechanical bellows may be utilized at the flange connections to facilitate thermal expansion and ease assembly of the distribution header and catalyst tubes. The distribution header may be in upstream communication with the catalyst tube inlets 36i to the catalyst tubes 36 for distributing ethanol to the catalyst tubes 36. The distribution header 39 may be located at the top of the dehydration reactor 34. The distribution openings 39o may be located at the bottom of the distribution header 39, and the catalyst tube inlets 36i may be located at the top of the catalyst tubes 36. The distribution header 39 distributes the supplied ethanol from the distribution openings 39o through the catalyst tube inlets 36i into the catalyst tubes 36.

[0038] The catalyst tubes 36 are filled with a dehydration catalyst for converting ethanol to ethylene. A collection header 50 collects ethylene from the catalyst tubes 36. The collection header 50 may be a pipe grid or may comprise a cylindrical or rectangular box with a tube plate fitted to the catalyst tubes 36. However, the collection header 50 has collection openings 50o that are continuous with the catalyst tube outlets 36o from the corresponding catalyst tubes 36. The openings 50o may have a single screen or a series of screens to retain the catalyst within the catalyst tubes 36 themselves. The collection header 50 may be in downstream communication with the catalyst tube outlets 36o to collect the ethylene product from the catalyst tubes 36. The collection header 50 may be located at the bottom of the dehydration reactor 34. The collection openings 50o may be located at the top of the collection header 50, and the catalyst tube outlets 36o may be located at the bottom of the catalyst tubes 36. The collection header 50 collects product ethanol from the catalyst tube outlets 36o of the catalyst tubes 36 via the collection openings 50o.

[0039] The catalyst tubes 36 extend through the fire chamber 65. The fire chamber 65 may be cylindrical or rectangular. The catalyst tubes 36 may hang along the vertical wall(s) 65w of the fire chamber 65. Alternatively, the catalyst tubes 36 may be positioned toward the center, so that the catalyst tubes 36 are exposed to the burners 42 on either side or around the catalyst tubes within the fire chamber 65. The vertical walls 65w may be cylindrical or planar. Top and bottom walls surround the fire chamber 65, which may provide a tube plate through which the catalyst tubes 36 extend. The distribution header 39 and collection header 50 may be outside the fire chamber 65. The distribution header 39, distribution opening 39o, and catalyst tube inlet 36i may be above the fire chamber 65. The collection header 50, collection opening 50o, and catalyst tube outlet 36o may be below the fire chamber 65. The firebox surrounds most of the length of each of the catalyst tubes 36 .

[0040] Burners 42 may be positioned on vertical wall(s) 65w of firebox 65. The vertical wall can be either a side wall or an end wall of firebox 65. Burners 42 can also be positioned on either the top wall, bottom wall, or any combination thereof of firebox 65. Fuel manifold 44 supplies hydrocarbon fuel to each burner 42 via fuel line 40 at a flow rate regulated by a control valve. Air manifold 46 similarly supplies air to each burner 42 via air line 41. The fuel ignites with the air and burns within firebox 65, providing enthalpy for the endothermic dehydration reaction occurring within catalyst tubes 36.

[0041] Each catalyst tube 36 has a catalyst inlet 48 near the catalyst tube inlet 36i and a catalyst outlet 52 near the catalyst tube outlet 36o. The catalyst inlet 48 may be located at the top of the catalyst tube 36, and the catalyst outlet 52 may be located at the bottom of the catalyst tube. Fresh catalyst is supplied to the catalyst tubes 36 through the catalyst inlet 48 by a fresh catalyst manifold 49, and spent catalyst is discharged from the catalyst tubes through the catalyst outlet 52 to a spent catalyst manifold 53. The catalyst inlet 48 and catalyst outlet 52 may be located outside the firebox 65 to facilitate on-stream supply and discharge of catalyst to and from the catalyst tubes 36, respectively. The tube inlet 36i and tube outlet 36o may be equipped with screens to prevent catalyst from exiting the catalyst tubes except through the catalyst inlet 48 and catalyst outlet 52, respectively. The screens may have openings smaller than the smallest dimension of the catalyst to prevent it from passing therethrough. The collection header 50 may be filled with inert balls or other inert particles 51 to support the screen in the catalyst outlet 36o. The inert balls may be made of ceramic.

[0042] The collection basket 54 may be in downstream communication with the collection header 50. An inlet 55 to the collection basket 54 may include a screen to prevent inert particles from entering the collection header 50. The collection basket 54 may be cylindrical. The collection basket 54 may include an inner perforated wall 56 having perforations 57 therein, defining a collection chamber 57 therein. An outer imperforate wall 58 outside the inner perforated wall 56 defines an annulus 60 therebetween. The outer imperforate wall 58 is only partially shown to reveal the inner perforated wall 56. The collection basket 54 may be secured to the collection header by a flange connection, with the flange of the collection basket 54 sandwiched between a flange depending from the collection header 50 and a flange of the outer imperforate wall 58. In FIG. 2, the closed side of the basket 54 is in downstream communication with the open side of the basket. In an alternative embodiment, the collection basket 54 may have an open side downstream of its closed side.

[0043] Product ethylene flows from the collection header 50 through perforations 57 in the inner perforated wall 56 into a collection chamber 59 defined by the inner perforated wall, enters an annulus 60, and flows to a discharge nozzle 62 in downstream communication with the annulus. The annulus 60 is preferably in downstream communication with the collection chamber 59, although the annulus may be in upstream communication with the collection chamber 59 if the basket extends toward the collection header 50. In the embodiment of FIG. 2, product ethylene flows from the collection chamber 59 to the annulus 60, although the reverse is also contemplated. An effluent line 32 discharges the product ethylene from the reactor 34. A temperature indicating controller (TIC) may be disposed on line 32 to measure the temperature of the ethylene effluent stream.

[0044] A TIC on the charge line 35 can measure the temperature of the charge stream entering the dehydration reactor 34, and a TIC on the outlet line 32 can measure the temperature of the dehydration stream. Each temperature can be sent as a signal to a temperature differential indicator controller (TDIC), which calculates the temperature difference and compares it to a setpoint. The TDIC can signal a control valve on the fuel manifold 44 to open further to increase the temperature difference if it is below or near the setpoint, or to close further to decrease the temperature difference if the temperature difference is above or near the setpoint.

[0045] FIG. 3 is a partial view of FIG. 2 showing an additional embodiment of the catalyst tubes 36 within the reactor 34. The distribution header 39 has flanged connections to the catalyst tubes between each of the distribution openings 39o and the corresponding catalyst tube inlets 36i. The distribution header 39 can be configured with each of the distribution openings 39o flanged to a mechanical bellows 61 connected to the corresponding catalyst tube inlets 36i. The mechanical bellows 61 facilitate differential thermal expansion and installation. The distribution header 39 can swing open to allow loading and unloading of catalyst from the catalyst tube inlets 36i. The collection header 50 has flanged connections to the catalyst tubes 36 between each of the collection openings 50o and the corresponding catalyst tube outlets 36o. The catalyst tubes and / or collection openings 50o may have a single screen 63 or a series of screens to support the catalyst within the catalyst tubes 36 themselves. This configuration may reduce the complexity or need for a collection basket 54.

[0046] The disclosed process and apparatus provides a dehydration reactor 34 that combines a furnace and a reactor in a single piece of equipment, thereby reducing the amount of equipment and footprint. The single dehydration reactor 34 can provide an isothermal reactor that can increase selectivity to the desired ethanol through efficient catalyst utilization and reduced utility requirements. [Example]

[0047] The inventors developed a kinetic model to compare the reactor of the present disclosure with an adiabatic reactor for ethanol dehydration. The model assumed a feed rate of 300 M gal / year, a steam rate of 300,000 lb / hr, and an ethanol conversion of 98% per pass. The table below shows the improvement provided by the isothermal reactor of the present disclosure.

[0048] [Table 1]

[0049] Specific Embodiments While the following will be described in conjunction with specific embodiments, it will be understood that this description is illustrative, but not intended to limit the scope of the preceding description and appended claims.

[0050] A first embodiment of the present disclosure is a process for producing ethylene, comprising: supplying ethanol to a plurality of catalyst tubes containing a dehydration catalyst in a firebox to convert the ethanol to ethylene; and burning fuel around the tubes in the firebox. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising supplying ethanol to a distribution header that distributes the ethanol to the tubes. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising collecting ethanol from the catalyst tubes in a collection header. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising supplying catalyst to the catalyst tubes through a catalyst inlet. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the catalyst inlet is outside the firebox. An embodiment of the present disclosure is one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising discharging catalyst from the catalyst tubes through a catalyst outlet. An embodiment of the present disclosure is one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, in which the catalyst outlet is outside the firebox. An embodiment of the present disclosure is one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising inert particles in the collection header. An embodiment of the present disclosure is one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising a collection basket in downstream communication with the collection header, the collection basket having an inner perforated wall and an outer non-perforated wall defining an annulus therebetween. An embodiment of the present disclosure is one, some, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, in which ethylene flows from the collection header into a collection chamber defined by an inner perforated wall, through perforations in the inner perforated wall, through the annulus, and to a discharge nozzle.

[0051] A second embodiment of the present disclosure is an apparatus for producing ethylene, comprising: a firebox including a burner on a side of the firebox; catalyst tubes within the firebox; a distribution header in communication with an inlet to the catalyst tubes for distributing ethanol to the catalyst tubes; a catalyst inlet to the catalyst tubes; a collection header in communication with an outlet from the catalyst tubes for collecting ethylene from the catalyst tubes; and a catalyst outlet from the catalyst tubes. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the second embodiment in this paragraph, in which the catalyst inlet is outside the firebox. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the second embodiment in this paragraph, in which the catalyst outlet is outside the firebox. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the second embodiment in this paragraph, in which the distribution header is outside the firebox. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the second embodiment in this paragraph, in which the collection header is outside the firebox. An embodiment of the present disclosure is one, some, or all of the preceding embodiment of this paragraph through the second embodiment of this paragraph, further comprising a collection basket in downstream communication with the collection header, the collection basket having an inner perforated wall and an outer non-perforated wall defining an annulus therebetween.

[0052] A third embodiment of the present disclosure is a process for producing ethylene, comprising: feeding ethanol to a distribution header that distributes the ethanol to a plurality of catalyst tubes containing a dehydration catalyst in a firebox to convert the ethanol to ethylene; burning fuel around the tubes in the firebox; and collecting ethylene from the catalyst tubes in a collection header. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the third embodiment in this paragraph, further comprising feeding catalyst to the catalyst tubes at the top of the catalyst tubes through a catalyst inlet. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the third embodiment in this paragraph, further comprising discharging catalyst from the catalyst tubes at the bottom of the catalyst tubes through a catalyst outlet. An embodiment of the present disclosure is any one, some, or all of the preceding embodiments in this paragraph through the third embodiment in this paragraph, wherein the catalyst inlet and catalyst outlet are outside the firebox.

[0053] Without further elaboration, it is believed that, using the preceding description, one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of the present invention, and can make various changes and modifications to the present invention to adapt it to various uses and conditions, without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0054] Above, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise indicated.

Claims

1. 1. A process for producing ethylene, comprising: supplying ethanol to a plurality of catalyst tubes containing a dehydration catalyst within a firebox to convert the ethanol into ethylene; burning fuel around tubes in said firebox.

2. 10. The process of claim 1 further comprising supplying the ethanol to a distribution header that distributes the ethanol to the tubes.

3. 3. The process of claim 2 further comprising collecting ethylene from the catalyst tubes in a collection header.

4. 1. An apparatus for producing ethylene, comprising: a firebox having a burner on a side of the firebox; a catalytic tube within the fire chamber; a distribution header in communication with the inlets to the catalyst tubes for distributing ethanol to the catalyst tubes; a catalyst inlet to the catalyst tube; a collection header in communication with an outlet from the catalyst tubes for collecting ethylene from the catalyst tubes; a catalyst outlet from the catalyst tube.

5. The apparatus of claim 4 wherein the catalyst inlet is external to the firebox.

6. The apparatus of claim 4 , wherein the catalyst outlet is external to the firebox.

7. 5. The apparatus of claim 4, wherein the tube includes a bellows at the catalyst inlet.

8. The apparatus of claim 4 , wherein the distribution header is external to the firebox.

9. The apparatus of claim 4 , wherein the collection header is external to the firebox.

10. 5. The apparatus of claim 4, further comprising a collection basket in downstream communication with the collection header, the collection basket having an inner perforated wall and an outer non-perforated wall defining an annulus therebetween.

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