Patent Description:
The present invention generally relates to methods for producing methyl tert-butyl ether (MTBE) and <NUM>-butene. More specifically, the present invention relates to integrated methods for producing methyl tert-butyl ether (MTBE) and <NUM>-butene that are capable of improving catalyst life for MTBE synthesis and increasing utilization rate of C<NUM> hydrocarbons from the feedstock compared to conventional MTBE production methods.

MTBE is used as a gasoline blending component. Typically, MTBE may be made by reacting isobutylene with methanol. The isobutylene for the reaction is usually obtained from a crude C<NUM> stream, which is usually a byproduct stream produced in a cracking process to produce olefins. More particularly, the crude C<NUM> stream can be obtained from steam cracking of hydrocarbons to produce ethylene and propylene. Generally, butadiene is removed from the crude C<NUM> stream before it is flowed into a MTBE synthesis unit.

The rest of the crude C<NUM> stream is then reacted with methanol in the MTBE synthesis unit in the presence of a catalyst to produce MTBE and a raffinate. The raffinate from the MTBE synthesis unit is further used to produce purified <NUM>-butene. In this process, the raffinate is subsequently processed in a separation unit consisting of two rectifiers in series to produce purified <NUM>-butene. However, generally, in the production process of MTBE and <NUM>-butene, the catalyst life in the MTBE synthesis unit is relatively limited due to catalyst deactivating compounds mixed in the feedstock during the removal of butadiene. Furthermore, the hydrocarbons in this process are not fully utilized, resulting in waste of <NUM>-butene and other C<NUM> hydrocarbons. Moreover, the <NUM>-butene separating/purification step is relatively energy intensive, causing a high production cost for <NUM>-butene.

<CIT> describes a process for producing a high purity butene-<NUM> product from n-butane via a dehydrogenation process.

<CIT> describes a process for simultaneous hydrogenation of an olefin and dehydrogenation of a paraffin in a combination hydrogenation/dehydrogenation unit having a single reaction zone.

Overall, while systems and methods for producing MTBE and <NUM>-butene exist, the need for improvements in this field persists in light of at least the aforementioned drawbacks.

A solution to at least some of the above-mentioned problems associated with the systems and methods for producing MTBE and <NUM>-butene has been discovered. The solution resides in methods of using an integrated system for producing MTBE and <NUM>-butene. Notably, a distillation unit is added to separate catalyst deactivating compounds, as well as <NUM>-butene and n-butane, from the C<NUM> mixture that enters the MTBE synthesis unit. The removal of the catalyst deactivating compounds can improve the catalyst life for MTBE synthesis. The separated <NUM>-butene is further processed to produce propylene via metathesis. Overall, the methods of the present invention can reduce the production cost for MTBE and/or <NUM>-butene by increasing catalyst life expectancy and fully utilizing the C<NUM> feedstock. Therefore, the methods of the present invention provide a technical solution to at least some of the problems associated with the currently available methods for producing MTBE and <NUM>-butene.

Embodiments of the invention include a method of producing methyl tertiary butyl ether (MTBE) and/or <NUM>-butene. The method comprises distilling a crude C<NUM> hydrocarbon stream that comprises n-butane, <NUM>-butene, <NUM>-butene, isobutane, isobutene, and a catalyst deactivating compound comprising dimethylformamide (DMF), acetonitrile (ACN), n-methyl-<NUM>-pyrolidone (NMP), furfural methoxy-propio-nitrile (MOPN), or combinations thereof, to produce: (<NUM>) a distillate stream comprising isobutene, isobutane, and <NUM>-butene; and (<NUM>) a bottom stream comprising <NUM>-butene, n-butane, and the catalyst deactivating compound. The method further comprises reacting the isobutene (isobutylene) of the distillate stream with methanol in the presence of a catalyst for MTBE synthesis to produce methyl tertiary butyl ether and an unreacted portion of the distillate stream. The method further still comprises separating the methyl tertiary butyl ether from the unreacted portion of the distillate stream, the unreacted portion comprising isobutane and <NUM>-butene. The method further still comprises flowing the bottom stream to an olefins conversion technology unit, wherein the olefins conversion technology unit comprises one or more metathesis reactors and one or more separation units; reacting at least some of the <NUM>-butene of the bottom stream with ethylene in the one or more metathesis reactors to form a reaction stream comprising propylene and liquefied petroleum gas; and separating the reaction stream in the one or more separation units to form a propylene stream comprising primarily propylene and an LPG stream comprising n-butane and unreacted <NUM>-butene. Moreover, in the method, distilling of the crude C4 hydrocarbon stream is carried out at a pressure of <NUM> to <NUM> bar; and the catalyst deactivating compound is capable of deactivating the catalyst for MTBE synthesis.

Embodiments of the invention include a method of producing methyl tertiary butyl ether (MTBE) and/or <NUM>-butene. The method comprises distilling a crude C<NUM> hydrocarbon stream that comprises n-butane, <NUM>-butene, <NUM>-butene, isobutane, isobutene, and a catalyst deactivating compound comprising dimethylformamide (DMF), acetonitrile (ACN), n-methyl-<NUM>-pyrolidone (NMP), furfural methoxy-propio-nitrile (MOPN), or combinations thereof, to produce: (<NUM>) a first distillate stream comprising one or more of isobutene, isobutane, and <NUM>-butene; and (<NUM>) a first bottom stream comprising the catalyst deactivating compound and one or more of <NUM>-butene and n-butane. The method further comprises reacting the isobutene of the distillate stream with methanol in the presence of a catalyst for MTBE synthesis to produce methyl tertiary butyl ether and an unreacted portion of the distillate stream. The method further comprises separating the methyl tertiary butyl ether from the unreacted portion of the distillate stream, the unreacted portion comprising isobutane and <NUM>-butene. The method further still comprises distilling the unreacted portion to produce a second distillate stream comprising isobutane and a second bottoms stream comprising primarily <NUM>-butene. The method further still comprises reacting the <NUM>-butene of the first bottom stream with ethylene to produce propylene in an olefins conversion technology unit by flowing the bottom stream to an olefins conversion technology unit, wherein the olefins conversion technology unit comprises one or more metathesis reactors and one or more separation units; reacting at least some of the <NUM>-butene of the bottom stream with ethylene in the one or more metathesis reactors to form a reaction stream comprising propylene and liquefied petroleum gas; and separating the reaction stream in the one or more separation units to form a propylene stream comprising primarily propylene and an LPG stream comprising n-butane and unreacted <NUM>-butene. Moreover, in the method, distilling of the crude C4 hydrocarbon stream is carried out at a pressure of <NUM> to <NUM> bar; and the catalyst deactivating compound is capable of deactivating the catalyst for MTBE synthesis.

The terms "wt. %" or "mol. %" refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, <NUM> moles of component in <NUM> moles of the material is <NUM> mol. % of component.

The terms "inhibiting" or "reducing" or "preventing" or "avoiding" or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.

The term "primarily," as that term is used in the specification and/or claims, means greater than any of <NUM> wt. %, <NUM> mol. %, and <NUM> vol. For example, "primarily" may include <NUM> wt. % to <NUM> wt. % and all values and ranges there between, <NUM> mol. % to <NUM> mol. % and all values and ranges there between, or <NUM> vol. % to <NUM> vol. % and all values and ranges there between.

Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

Currently, MTBE is produced using a C<NUM> hydrocarbon mixture from a steam cracker as feedstock. The C<NUM> hydrocarbon mixture is first processed to remove butadiene and the isobutylene in the remainder of the C<NUM> hydrocarbon mixture is reacted with methanol to form MTBE and a raffinate. The raffinate from the MTBE synthesis unit is further distilled in two rectifiers in series to produce purified <NUM>-butene. However, the catalyst deactivating compounds flowed into the MTBE synthesis unit with the remainder of the C<NUM> hydrocarbon mixture can significantly reduce the life expectancy for the catalyst of the MTBE synthesis unit. Furthermore, the C<NUM> hydrocarbon feedstock, especially <NUM>-butene, is not fully utilized to minimize the production cost of MTBE and/or <NUM>-butene. The present invention provides a solution to one or more of these problems. The solution is premised on a method that include using a distillation column to separate the remainder of the C<NUM> hydrocarbon mixture that flows to the MTBE synthesis unit into a distillate stream that comprises <NUM>-butene, isobutane and isobutylene, and a bottom stream that comprises <NUM>-butene, n-butane and the catalyst deactivating compound. Thus, the catalyst deactivating compound is removed from the MTBE synthesis unit to avoid poisoning the catalyst for MTBE synthesis. Furthermore, the <NUM>-butene can be separated from the raffinate from the MTBE synthesis unit with a single distillation step, rather than using two distillation steps in a conventional process resulting in reduced energy consumption for purifying <NUM>-butene. Moreover, the separated <NUM>-butene is used to produce propylene via metathesis, thereby increasing the utilization rate of the C<NUM> hydrocarbon mixture and reducing the production costs for MTBE and/or <NUM>-butene. These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

Method <NUM> for producing MTBE and/or <NUM>-butene using crude C<NUM> hydrocarbon mixture as the feedstock may be implemented by system <NUM>, as shown in <FIG>. The system for producing MTBE and/or <NUM>-butene can include a first distillation column, a MTBE synthesis unit, and a second distillation column. With reference to <FIG>, a schematic diagram is shown of system <NUM> for producing MTBE and/or <NUM>-butene with an improved catalyst life expectancy and reduced production cost.

System <NUM> may comprise first distillation column <NUM> configured to receive and distill crude C<NUM> hydrocarbon stream <NUM> to form: (<NUM>) first distillate stream <NUM> comprising isobutylene, isobutane, and <NUM>-butene and (<NUM>) first bottom stream <NUM> comprising <NUM>-butene and n-butane. In embodiments of the invention, crude C<NUM> hydrocarbon stream <NUM> may comprise <NUM>-butene, <NUM>-butene, isobutane, isobutylene, and n-butane. According to embodiments of the invention, crude C<NUM> hydrocarbon stream <NUM> may be obtained by flowing a C<NUM> hydrocarbon stream from a stream cracker and removing butadiene from the C<NUM> hydrocarbon stream to form C<NUM> hydrocarbon stream <NUM>. According to embodiments of the invention, butadiene from the C<NUM> hydrocarbon stream may be removed via extraction and/or selective hydrogenation.

An overhead outlet of first distillation column <NUM> may be in fluid communication with MTBE synthesis unit <NUM> such that first distillate stream <NUM> flows from first distillation column <NUM> to MTBE synthesis unit <NUM>. MTBE synthesis unit <NUM> may include one or more MTBE synthesis reactors and one or more separation units. The one or more MTBE synthesis reactors may be configured to react isobutylene (isobutene) of first distillate stream <NUM> with methanol to produce MTBE. The one or more separation units may be configured to separate effluent from the one or more MTBE synthesis reactors to form (a) MTBE stream <NUM> comprising primarily MTBE and (b) raffinate stream <NUM> comprising primarily isobutane and <NUM>-butene collectively. The MTBE synthesis reactor(s) may contain a catalyst selected from the group consisting of acidic resins, zeolites, fluorine promoted SiO<NUM>-Al<NUM>O<NUM> and sulfur promoted ZrO<NUM>, or combinations thereof.

An outlet of MTBE synthesis unit <NUM> may be in fluid communication with second distillation column <NUM> such that raffinate stream <NUM> flows from MTBE synthesis unit <NUM> to second distillation column <NUM>. Second distillation column <NUM> may be configured to separate raffinate stream <NUM> to form second distillate stream <NUM> comprising <NUM> to <NUM> wt. % isobutane, and <NUM>-butene stream <NUM> comprising <NUM> to <NUM> wt. % <NUM>-butene.

As shown in <FIG>, a bottom outlet of first distillation column <NUM> may be in fluid communication with isomerization unit <NUM> such that at least some of first bottom stream <NUM> flows from first distillation column <NUM> to isomerization unit <NUM>. Isomerization unit <NUM> may be configured to isomerize at least some <NUM>-butene of first bottom stream <NUM> to <NUM>-butene. Isomerization unit <NUM> may contain a catalyst including iridium pincer complex catalysts, or supported catalysts containing at least one noble metal from Group VIII, selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium and platinum, or nickel. The catalyst may be processed by a sulfur-containing compound, then by hydrogen prior to being used. An outlet of isomerization unit <NUM> may be in fluid communication with an inlet of distillation column <NUM> such that isomerized recycle stream <NUM> from isomerization unit <NUM> flows from isomerization unit <NUM> to first distillation column <NUM>. Isomerized recycle stream <NUM> may be combined with crude C<NUM> hydrocarbon stream <NUM> before it flows to first distillation column <NUM>. Isomerized recycle stream <NUM> may comprise one or more of <NUM>-butene, <NUM>-butene, and n-butane.

Alternatively or additionally, as shown in <FIG>, the bottom outlet of first distillation column <NUM> may be in fluid communication with olefins conversion technology unit <NUM> such that first bottom stream <NUM> flows from first distillation column <NUM> to olefins conversion technology unit <NUM>. Olefins conversion technology unit <NUM> may be configured to react at least some <NUM>-butene of first bottom stream <NUM> with ethylene to produce propylene (propene) via metathesis. Olefins conversion technology unit may contain a catalyst comprising Schrock catalysts, tungsten oxide on silica or alumina support, molybdenum oxide on silica or alumina support, rhenium oxide on silica or alumina support, cobalt molybdate on alumina and mixtures therefor, or combinations thereof. Olefins conversion technology unit <NUM> may comprise one or more metathesis reactors and one or more separation units such that a reaction stream from the one or more metathesis reactors is separated in the one or more separation units to form propylene stream <NUM> comprising primarily propylene (i.e., propene) and a LPG stream comprising n-butane and/or unreacted <NUM>-butene.

Methods of producing MTBE and/or <NUM>-butene have been discovered for improving the life expectancy of the catalyst for MTBE synthesis, increasing the utilization rate of C<NUM> hydrocarbon feedstocks, and reducing the production costs for MTBE and <NUM>-butene. As shown in <FIG>, embodiments of the invention include method <NUM> for producing MTBE and/or <NUM>-butene using crude C<NUM> hydrocarbon mixture as the feedstock. Method <NUM> may be implemented by system <NUM>, as shown in <FIG>. According to embodiments of the invention, method <NUM> may include distilling, in first distillation column <NUM>, crude C<NUM> hydrocarbon stream <NUM> to produce first distillate stream <NUM> and first bottom stream <NUM>, as shown in block <NUM>.

In embodiments of the invention, crude C<NUM> hydrocarbon stream <NUM> may be obtained by removing butadiene from a C<NUM> hydrocarbon mixture from a steam cracker. According to embodiments of the invention, the C<NUM> hydrocarbon mixture from a steam cracker may comprise <NUM>-butene, <NUM>-butene, isobutylene, n-butane, butadiene, and isobutane. Removing butadiene from the C<NUM> hydrocarbon mixture from the steam cracker may be accomplished using solvent extraction. Crude C<NUM> hydrocarbon stream <NUM> may comprise n-butane, <NUM>-butene, <NUM>-butene, isobutane, isobutene, <NUM>,<NUM>-butadiene, <NUM>,<NUM>-butadiene, and a catalyst deactivating compound comprising dimethylformamide (DMF), acetonitrile (ACN), n-methyl-<NUM>-pyrolidone (NMP), furfural methoxy-propio-nitrile (MOPN), or combinations thereof. According to embodiments of the invention, crude C<NUM> hydrocarbon stream <NUM> may comprise <NUM> to <NUM> wt. % catalyst deactivating compound and all ranges and values there between including <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. The catalyst deactivating compound is capable of deactivating a catalyst for MTBE synthesis. The catalyst deactivating compound may be introduced through the solvent extraction process for removing butadiene from the C<NUM> hydrocarbon mixture.

In embodiments of the invention, first distillate stream <NUM> comprises primarily isobutylene, isobutane, and <NUM>-butene, collectively. According to embodiments of the invention, first distillate stream <NUM> may further comprise <NUM> to <NUM> ppm catalyst deactivating compound and all ranges and values there between including <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, <NUM> to <NUM> ppm, and <NUM> to <NUM> ppm. First bottom stream <NUM> may comprise primarily <NUM>-butene, n-butane, and the catalyst deactivating compound. According to embodiments of the invention, first bottom stream <NUM> may include <NUM> to <NUM> wt. % catalyst deactivating compound and all ranges and values there between including ranges of <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. In embodiments of the invention, the catalyst deactivating compound may be flowed into first bottom stream <NUM>, as shown in <FIG>, and then to a liquefied petroleum gas stream. In embodiments of the invention, distilling of crude C<NUM> hydrocarbon stream <NUM> in first distillation column <NUM> at block <NUM> may be carried out under operating conditions including a bottom boiling temperature range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The operating conditions of first distillation column <NUM> at block <NUM> may further include an overhead boiling temperature range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The operating conditions of first distillation column <NUM> at block <NUM> may further still include a molar reflux ratio in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The operating conditions of first distillation column <NUM> at block <NUM> may further still include an operating pressure of <NUM> to <NUM> bar and all ranges and values there between including <NUM> bar, <NUM> bar, <NUM> bar, <NUM> bar, <NUM> bar, and <NUM> bar. In embodiments of the invention, a number of theoretical plates for first distillation column <NUM> may be in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>.

Method <NUM> may further include reacting, in MTBE synthesis unit <NUM>, the isobutylene of first distillate stream <NUM> with methanol in the presence of a catalyst for MTBE synthesis to produce methyl tertiary butyl ether and an unreacted portion of first distillate stream <NUM>, as shown in block <NUM>. In embodiments of the invention, reacting in MTBE synthesis unit, at block <NUM> may be carried out at a reaction temperature of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. Reacting in MTBE synthesis unit <NUM> at block <NUM> may be carried out at a reaction pressure of <NUM> to <NUM> bar and all ranges and values there between including ranges of <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, and <NUM> to <NUM> bar. A volumetric ratio of methanol to first distillate stream <NUM> feeding to MTBE synthesis unit <NUM> may be in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>.

As shown in block <NUM>, method <NUM> may further include separating the MTBE from the unreacted portion of first distillate stream <NUM> to form MTBE stream <NUM> comprising primarily MTBE and raffinate stream <NUM> comprising primarily isobutane and <NUM>-butene. In embodiments of the invention, at block <NUM>, about <NUM> to <NUM>% of MTBE that is produced at block <NUM> may be recovered. In embodiments of the invention, MTBE stream <NUM> may comprise <NUM> to <NUM> wt. Raffinate stream <NUM> may comprise about <NUM> to <NUM> wt. % <NUM>-butene and about <NUM> to <NUM> wt. % isobutane. In embodiments of the invention, the separating at block <NUM> may be carried out in the separation unit of MTBE synthesis unit comprising one or more distillation columns, reactive distillation columns, or combinations thereof.

According to embodiments of the invention, as shown in block <NUM>, method <NUM> may further include distilling, in second distillation column <NUM>, raffinate stream <NUM> to produce second distillate stream <NUM> comprising <NUM> to <NUM> wt. % isobutane and second bottom stream <NUM> comprising <NUM> to <NUM> wt. % <NUM>-butene. In embodiments of the invention, the distilling in second distillation column <NUM> at block <NUM> may be carried out under operating conditions comprising an overhead boiling temperature range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The bottom boiling temperature range of the distilling at block <NUM> may be <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The operation conditions of second distillation column <NUM> may further include a molar reflux ratio in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. Second distillation column <NUM> may have a theoretical plates number in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>.

According to embodiments of the invention, method <NUM> may further include isomerizing, in isomerization unit <NUM>, at least some of the <NUM>-butene in first bottom stream <NUM> to form <NUM>-butene in isomerized recycle stream <NUM>, as shown in block <NUM>. In embodiments of the invention, isomerized recycle stream <NUM> may comprise <NUM>-butene, <NUM>-butene, n-butane, or combinations thereof. Isomerized recycle stream <NUM> may further include the catalyst deactivating compounds. As an alternative to or in additional to flowing deactivating compounds in recycle stream <NUM>, the catalyst deactivating compound from first bottom stream <NUM> may be removed by a guard bed (not shown in <FIG>) before first bottom stream <NUM> enters isomerization unit <NUM>. As an alternative to or in addition to being removed, the catalyst deactivating compound may pass through isomerization unit <NUM>. According to embodiments of the invention, isomerizing in isomerization unit <NUM> at block <NUM> may be carried out at a reaction temperature of <NUM> to <NUM> and a reaction pressure of <NUM> to <NUM> bar. In embodiments of the invention, at block <NUM>, <NUM>-butene may be converted at a conversion rate of <NUM> to <NUM>% and all ranges and values there between including ranges of <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, and <NUM> to <NUM>%. In embodiments of the invention, method <NUM> may further still include combining isomerized recycle stream <NUM> with crude C<NUM> hydrocarbon stream <NUM>, as shown in block <NUM>. The combined stream may be flowed to first distillation column <NUM>.

At least some of first bottom stream <NUM> may be flowed to olefins conversion technology unit <NUM> and reacted with ethylene under reaction conditions sufficient to produce propylene via metathesis, as shown in block <NUM>. In embodiments of the invention, an unreacted portion of first bottom stream <NUM> may be separated from propylene to form LPG stream <NUM> comprising primarily n-butane and/or unreacted <NUM>-butene. In embodiments of the invention, at block <NUM>, the reaction conditions may include a reaction temperature in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The reaction conditions at block <NUM> may further include a reaction pressure of <NUM> to <NUM> bar and all ranges and values there between including <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, <NUM> to <NUM> bar, and <NUM> to <NUM> bar. In embodiments of the invention, at block <NUM>, unreacted ethene and unreacted <NUM>-butene from olefins conversion technology unit <NUM> may be recycled to an inlet of olefins conversion technology unit <NUM>, and the <NUM>-butene may be converted at a conversion rate of <NUM> to <NUM>% per pass and all ranges and values there between including <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, and <NUM> to <NUM>%. According to embodiments of the invention, a total conversion rate for the <NUM>-butene at block <NUM> may be in a range of <NUM> to <NUM>% and all ranges and values there between including <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, and <NUM> to <NUM>%. In embodiments of the invention, the deactivating compounds may pass through olefins conversion technology unit <NUM>. As an alternative to or in addition to passing the deactivating compounds through olefins conversion technology unit <NUM>, the catalyst deactivating compound may be removed by a guard bed (not shown in <FIG>) before first bottom stream <NUM> enters olefins conversion technology unit <NUM>. In embodiments of the invention, the catalyst deactivating compound that passes through olefins conversion technology unit <NUM> may be flowed in LPG stream <NUM>.

Although embodiments of the present invention have been described with reference to blocks of <FIG>, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in <FIG>. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of <FIG>.

As part of the disclosure of the present invention, a specific example is included below. The example is for illustrative purposes only and are not intended to limit the invention. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.

Compositions of a first distillate stream (corresponding to first distillate stream <NUM> of <FIG>) (Table <NUM>) and a second distillate stream <NUM> (corresponding to second distillate stream <NUM> of <FIG>) (Table <NUM>) have been simulated using AspenPlus v10. <NUM> for the system as shown in <FIG>. The simulation included flowing about <NUM> ton/hr of a C<NUM> hydrocarbon stream (corresponding to C<NUM> hydrocarbon stream <NUM> in <FIG>) to the first distillation column (corresponding to first distillation column <NUM> in <FIG>). The composition of the crude C<NUM> hydrocarbon stream is shown in Table <NUM>. The first distillate stream was flowed to a MTBE synthesis unit (corresponding to MTBE synthesis unit <NUM> in <FIG>), where the isobutene in the first distillate stream was reacted with <NUM> ton/hr of methanol in two reactors within the MTBE synthesis unit. In the simulation, <NUM> ton/hr of the second distillate stream, which is rich in isobutane, was recycled and mixed with the first distillate stream before entering the MTBE synthesis unit.

In the simulation, about <NUM> ton/hr of a MTBE stream (corresponding to MTBE stream <NUM> in <FIG>) was formed and further recovered by two distillation columns. The raffinate from the MTBE synthesis unit comprising primarily <NUM>-butene and isobutane was flowed to a second distillation column (corresponding to second distillation column <NUM> in <FIG>) to produce a second bottom stream comprising more than <NUM> wt. % <NUM>-butene. Purity of <NUM>-butene can be improved by increasing the duties of the second distillation column or increasing the ratio of methanol to isobutene in MTBE synthesis unit.

Claim 1:
A method of producing methyl tertiary butyl ether (MTBE) and/or <NUM>-butene, the method comprising:
distilling a crude C<NUM> hydrocarbon stream that comprises n-butane, <NUM>-butene, <NUM>-butene, isobutane, isobutene, and a catalyst deactivating compound comprising dimethylformamide (DMF), acetonitrile (ACN), n-methyl-<NUM>-pyrrolidone (NMP), furfural methoxy-propionitrile (MOPN), or combinations thereof, to produce: (<NUM>) a distillate stream comprising isobutene, isobutane, and <NUM>-butene; and (<NUM>) a bottom stream comprising <NUM>-butene, n-butane, and the catalyst deactivating compound;
reacting the isobutene of the distillate stream with methanol in the presence of a catalyst for MTBE synthesis to produce methyl tertiary butyl ether and an unreacted portion of the distillate stream; and
separating the methyl tertiary butyl ether from the unreacted portion of the distillate stream, the unreacted portion comprising isobutane and <NUM>-butene;
flowing the bottom stream to an olefins conversion technology unit, wherein the olefins conversion technology unit comprises one or more metathesis reactors and one or more separation units;
reacting at least some of the <NUM>-butene of the bottom stream with ethylene in the one or more metathesis reactors to form a reaction stream comprising propylene and liquefied petroleum gas; and
separating the reaction stream in the one or more separation units to form a propylene stream comprising primarily propylene and an LPG stream comprising n-butane and unreacted <NUM>-butene
wherein the distilling of the crude C4 hydrocarbon stream is carried out at a pressure of <NUM> to <NUM> bar;
wherein the catalyst deactivating compound is capable of deactivating the catalyst for MTBE synthesis.