KR100188326B1 - Etherification process - Google Patents

Abstract

Separating the first etherification reactor effluent as a first feed, the feed into a first stream consisting of the first ether product and a second stream consisting of unreacted alcohol, tertiary olefins and other nonreactive compounds. The first separation means for passing through; Passing the second stream through a reactor zone having an acidic ion exchange resin therein, wherein the alcohol and tertiary olefins of the second stream react to form a second ether product contained in the second reactor effluent stream; Passing a portion of the second reactor outflow as a second feed to the first separation means; Separating the remainder of the second reactor effluent into a third stream consisting of a second ether product and a fourth stream consisting of unreacted alcohol, tertiary olefins and other nonreactive compounds. Etherification process consisting of reacting primary or secondary alcohols with tertiary olefins, consisting of passing through a second separation means.

Description

Etherification process

1 is a schematic process flow diagram illustrating a preferred embodiment of the present invention having three sections comprising a first reaction section, a second reaction section, and an alcohol recovery section.

2 is a schematic process flow diagram illustrating an alternative embodiment of a second reaction zone of the process of the present invention.

3 is a schematic process flow diagram illustrating another embodiment of a second reaction zone of the process of the present invention.

* Explanation of symbols for main parts of the drawings

10 etherification process system 12 first reaction zone

14, 100, 110: second reaction section 16: alcohol recovery section

Conduits: 18, 20, 22, 26, 30, 33, 36, 38, 42, 44, 46, 52, 56, 58, 60, 64, 66, 112

24 first etherification reactor vessel 28 first separation means

32 second etherification reactor vessel 34, 114 heat exchanger

40 second separation means 50 contact means

54 third separation means 62 fourth separation means

The present invention relates to the preparation of alkyl tertiary alkyl ether compounds.

It is known that alkyl tertiary ether ether compounds can be prepared by reacting a primary or secondary alcohol with an olefin compound having a double bond on a tertiary carbon atom in the presence of an acidic ion exchange resin catalyst. Particularly more common etherification reactions include reacting methanol with isobutylene or isoamylene to produce methyl tertiary butyl ether (MTBE) and methyl tertiary amyl ether (TAME), respectively. These tertiary ether ether compounds are particularly useful as octane enhancers for liquid fuels, especially gasoline. In addition, because of the low vapor pressure of these compounds, they are particularly useful for reducing the vapor pressure of gasoline. Recent federal legislation requires that motor gasoline be recombined to contain higher concentrations of oxidizing compounds, and tertiary alkyl ether compounds of these oxidizing compounds are particularly suitable to help comply with these new federal laws. Kicked out

Although processes for the preparation of high octane tertiary ethers are known in the art, several problems still remain with known processes that have not been solved by those skilled in the art to date. In particular, since standard etherification reactions are equilibrium type reactions, most etherification processes do not provide an economical means that do not result in high energy and capital costs in order to obtain high olefin conversion. Another problem with known etherification processes is the inability to selectively produce MTBE products or TAME products in processes that result in high tertiary olefin conversion without causing significant modifications in process flow diagrams and process equipment. Another problem faced by those in the field of etherification processes is the difficulty of removing cyclopentene compounds, which may be contained in the etherification process feed together with the ether product produced in the etherification section of the process. It is preferred that any feed of cyclopentene to the etherification process system be removed together with the ether product, which potentially reduces the cyclopentene to downstream processes to which non-reactive compounds contained in the feed stream of the etherification process will be fed. This can have a negative impact. After all, it is desirable to have an etherification process that provides a high purity product stream to be produced, at low operating costs, as in most process technology cases.

The process of the present invention comprises passing an etherification reactor effluent as a first feed to a first separation means, the separation means passing the feed to a first stream containing the first ether product and to a primary alcohol. And a second stream containing tertiary olefins. The second stream is sent to a reaction zone containing an acidic ion exchange resin, wherein the primary alcohol and tertiary olefin in the second stream react to form a second ether product contained in the reactor effluent stream. At least a portion of the reactor effluent stream is passed to the first separation means while the remainder of the reactor effluent not sent to the first separation means is sent to the second separation means. The remainder of the reactor effluent stream is passed through a second separation means, which separates the reactor effluent stream into a third stream consisting of the second ether product and a fourth stream consisting of hydrocarbon and primary alcohol. will be. Thus, the remaining reactor effluent stream not passed through the second separation means is sent to the first separation means as a second feed.

The process of the present invention has a number of unique features that do not have prior art etherification processes. For example, one novel feature of the process is the inclusion of a second etherification zone within the reflux loop of the fractionator used to separate the etherification product. In general, and preferably, at least part of the etherification reaction product of the second etherification reaction zone is preferably as feed, most preferably since the second etherification reaction zone is included in the reflux loop of the classifier. Will be passed back to the fractionator as reflux. The importance of using the second reaction section in this way is that it provides a very high overall conversion of the reactive olefin compound throughout the etherification process, but at a much lower cost than the operation and capital costs of the prior art process. . None of the prior art disclosed the use of a second reaction zone in the overhead system reflux loop of the fractionator to provide high tertiary olefin conversion and low energy and capital costs.

The process of the present invention comprises two separate reaction sections and an alcohol recovery section. Each reaction section includes a reactor vessel for defining a reaction section having an appropriate etherification catalyst therein for promoting or catalyzing the etherification reaction between the reactive tertiary olefin compound and the primary or secondary alcohol. A feed stream consisting of tertiary olefins and primary alcohols is introduced or fed into the first reaction zone of the first reaction section of the process, where it is suitable reaction conditions to promote the reaction of the tertiary olefins and alcohols contained in the feed stream. Contacting the etherification catalyst under an etherification reactor effluent or first reaction zone effluent stream.

The first reaction zone effluent stream is then directed to the second reaction zone, where it is the ash 1 ether product stream containing the etherification reaction product, and the non-reactive compound that remains unconverted and is charged to the first reaction zone of the process. Is first separated by means of separation to separate the flow into another stream containing, isoolefin and alcohol. The flow containing the non-reactive compound and unreacted isoolefins and alcohols is then contained in a reactor vessel which is identical or substantially similar to that used in the first reaction zone and which defines the reaction zone under suitable etherification reaction conditions. Contacting with an acidic ion exchange resin catalyst to produce a second reaction zone reactor effluent stream. This second reaction zone reactor effluent stream then goes to a second reaction zone reactor directed to a second separation means for separating the ether product produced in the second reaction zone from other non-reactive compounds and unreacted isoolefins and alcohols. Divide into two streams with any portion of the effluent stream. At least some of the second reaction zone reactor effluent stream is fed to a first separation means in which the ether product contained therein is separated from unreactive compounds, isoolefins and alcohols. Suitable embodiments of the invention include at least a portion of the second reaction zone reactor effluent stream being sent to the first separation means, preferably as feed, and most preferably as reflux. In this suitable embodiment of the invention, the second reaction section reactor effluent stream of the remainder which is not fed to the first separation means is sent to the second separation means or used as feed.

The non-reactive compounds, unreacted isoolefins and alcohols separated by the second separation means are separated from the non-reactive compounds introduced into the etherification process system 10 and recovered for reuse, and two etherifications are performed. Undesired reaction by-products produced in the reaction zone are sent to the alcohol recovery section where it is recovered. Undesired reaction by-products are generally oxidizing compounds, and in particular the most common undesirable reaction by-products are dimethyl ether, which is the reaction product produced by reacting two molecules of methanol. Dimethyl ether compounds are undesirable in that they have a high vapor pressure which negatively affects gasoline pools by raising the overall vapor pressure. Therefore, it is desirable to remove the dimethylether compound from the gasoline pool and use it elsewhere, such as in a fuel gas stream of a process plant. An additional problem with the reaction byproduct dimethyl ether is its impact on the downstream stream alkylation process. When dimethyl ether is fed to the HF alkylation process and the non-reactive olefin compound to pass through the etherification process is consumed, the consumption of acid in the process is due to unwanted reaction with dimethyl ether in the feed. Increased dramatically. The process of the invention described herein provides an effective means for removing the dimethyl ether from the alkylation feed stream to eliminate the problems associated with having the compound contained in the feed to the HF alkylation process.

Non-reactive compounds separated by alcohol recovery sections can be sent along the stream for later processing, in which case these compounds are mainly hydrocarbons and, in particular, olefin hydrocarbons, they often react with isoparaffins to form high octane alkylate compounds It is fed to an alkylation process to produce It is important that non-reactive compound streams contain minimum concentration levels of such compounds due to the negative effects of compounds such as cyclopentane on the alkylation process. As will be discussed further herein, some alternative embodiments of the present invention provide for minimizing the concentration level of cyclopentene in rejected non-reactive compounds passing along the flow to the alkylation process. In addition, several other embodiments of the process of the present invention provide for high removal and recovery of undesirable reaction byproducts generated in the etherification process, ie dimethylether.

The alcohol recovery section may be any suitable process section for separating solute components contained in the solution, preferably primary alcohols, from the remaining compounds of the solution, which are primarily hydrocarbons. In general, the alcohol recovery section employs a conventional liquid-liquid extraction or solvent extraction method in which the feed solution is in intimate contact with the solvent by the use of contact means to produce an extraction stream and an extraction residue stream containing an alcohol solute-rich solvent. The type of inclusion is appropriate. The extract residue stream is essentially a feed stream that is fed to the contacting means having a low alcohol content and causing a substantial reduction in alcohol content. The extraction stream is sent to a separation means, which is preferably a conventional fractionator for separating the alcohol from the solvent. The separated alcohol is recycled and used as the reaction feed to the first reaction section of the etherification process. The recovered solvent is recycled and reused in the contact means for recovering alcohol from its feed stream. The extract residue stream is sent to a separation means for separating the extract residue into an oxide rich stream and a hydrocarbon stream. Conventional fractionation techniques can be used to separate hydrocarbons from oxidizing compounds contained in the extract residue stream. Any solvent having suitable properties for removing alcohol solutes from hydrocarbon and alcohol solutions may be used in the process of the present invention, but a suitable solvent is water.

As noted above, the feed to the first reaction section of the etherification process is a stream having a primary or secondary alcohol stream with isoolefins and other compounds that are unreactive under certain etherification conditions in the presence of an acidic ion exchange resin catalyst. It is the mixing flow which is made up. In general, isoolefins include hydrocarbons having 4 to 16 carbon atoms per molecule. Examples of the isoolefins are isobutylene, isoamylene, isohexylene, isoheptylene, isooctylene, isononylene, isodedecylene, isoundecylene, isododecylene, isotridecylene, isoteratedecylene , Cyopentadecylene and isohexadecylene, or mixtures of two or more thereof.

Alcohols that can be fed or fed to the first etherification reaction zone include methanol, ethanol, propanol, isopropanol, primary and secondary butanol, pentanol, hexanol, ethylene, glycol, propylene glycol, butylene glycol, polyglycol, and glycerol Primary and secondary aliphatic alcohols having 1 to 12 carbon atoms, such as and the like, or mixtures of two or more thereof.

Currently, the reactants of suitable etherification processes are methanol and isobutylene and / or amylene, because they produce methyl tertiary butyl ether (MTBE) and methyl tertiary amyl ether (TAME). Thus, isoolefins are currently preferably isobutylene or isoamylene predominantly having a double bond on the tertiary carbon atom of the isoamylene compound, or both isobutylene and isoamylene and predominantly methanol are alcohols. Do.

In general, it is preferred that the isoolefins and alcohols pass through the etherification reaction zone in the presence of a diluent which is unreactive under etherification conditions without detrimental effect on the etherification reaction. Examples of suitable diluents include alkanes and straight chain olefins. The feed to the reactor except the alcohol is generally diluted to comprise about 2 to about 80 weight percent, preferably about 10 to about 60 weight percent isoolefins.

Any suitable molar ratio of alcohol to isoolefin in the feed stream to the etherification reactor zone can be used in the present invention which will provide the desired high tertiary olefin conversion pursued by the process of the present invention. Generally, the molar ratio of alcohol to isoolefin in the feed to the etherification reaction zone will range from about 0.5: 1 to about 4: 1, but preferably the molar ratio can range from about 0.8: 1 to about 1.2: 1. However, in order to obtain the highest conversion of isoolefins in the process feed to the etherification reaction zone, it is most desirable to bring the molar ratio of alcohol to isoolefin close to 1: 1, as can be obtained in practice.

Typical etherification reactions are well known in the art and, in the case of the present invention, with the exception of the second reaction zone where the operating pressure affects the energy utilization of the first separation means, they are not critical. As will be explained by the examples herein, from the operation of the second etherification reaction zone at a low operating pressure, it reduces the energy required to provide the separation performed by the first separation means. There is a positive advantage that is not disclosed in. The temperature for the etherification reaction zone and the space velocity to the etherification reaction zone with respect to the feed can be selected as desired depending on the degree of olefin conversion pursued, but in general, they provide the highest olefin conversion economically viable. It must be provided. In general, the temperature of the reaction zone will range up to about 150 ° C. Preferably, the etherification reaction temperature may range from about 30 ° C to about 120 ° C, and most preferably, the temperature will range from about 35 ° C to about 80 ° C. The operating pressure of the etherification reaction zone is generally chosen to ensure that the feed stream or charge to the reaction zone and the product flow from the reaction zone remain in the liquid phase during the etherification reaction. Exemplary pressures range from about 30 psig to about 300 psig, but, as described above, if it is feasible to operate the second etherification reaction zone at an operating pressure of 20 psig or less, significant energy in operating the first separation means. It may be chosen to obtain a reduction in consumption, and therefore this will make the novel process described herein to be much more refined to operate than the prior art processes. In most situations, however, the etherification reaction must be carried out in the liquid phase. Generally, the liquid hourly space velocity (LHSV) of the feed to the etherification reactor will range from about 1 hour ⁻¹ to about 20 hours ⁻¹ , but preferably LHSV is from about 2 hours ⁻¹ to about 10 Time ^-1 range. Most preferably, the LHSV may range from 3 hours ⁻¹ to 5 hours ⁻¹ .

The etherification reaction is to selectively react tertiary olefins with alcohols, preferably methanol, to form tertiary ether compounds. The etherification reaction is an equilibrium type reaction that can be expressed as follows:

Due to the equilibrium constant values and temperature dependence of the reactions described above, the equilibrium conditions leading to the formation of the tertiary ether product are low reactor temperature conditions, but in any case, the ether product of the tertiary olefins contained in the reaction zone, since the etherification reaction is an equilibrium type reaction. Conversion to is thermodynamically limited. Surprisingly, the etherification reaction process comprises a second reaction stage having a second reaction stage necessarily followed by a separation stage following the first reaction stage, and wherein the second reaction stage is arranged in a reflux loop of the fractionator acting as a separation stage It has been found that branching can be performed in two steps, thereby increasing the tertiary olefin conversion. Thus, the entire overhead stream from the separation stage following the first reaction stage will be sent to the second reaction stage with at least a portion of the resulting second reaction stage effluent passing through the separation stage as reflux.

By utilizing the features and improvements of the novel ertrification process, high tertiary olefin conversion can be obtained. For example, in the case of an MTBE manufacturing mode process, the conversion of isobutylene through the process can exceed about 96% by weight. However, preferably the isobutylene conversion is greater than about 98% by weight, and most preferably, the isobutylene conversion may be greater than 99% by weight. In the case of the TAME preparation process, the conversion of isoamylene is not as high as the conversion of isobutylene due to different reaction kinetics and thermodynamic relationships. However, very high isoamylene conversion can be obtained using the process of the present invention having a conversion of greater than about 88% by weight, but preferably greater than about 90% by weight. The most suitable isoamylene conversion obtained from the use of the novel inventive process described herein is 92% by weight.

The acid ion exchange catalyst used in the etherification reaction zone of the present invention is a relatively high molecular weight carbon material having at least one SO ₃ H functional group. These catalysts are exemplified by sulfonated coals (Zeo-Karb H, Nalcite X and Nalcite AX) prepared by bituminous coal treatment with sulfuric acid and sold commercially as zeolite water softeners or base exchangers. These materials are usually available in neutralized form, in which case they must be activated in hydrogen form by treatment with water and strong inorganic acids such as hydrochloric acid which are washed to remove sodium and chloride ions before use. Sulfonated resin catalysts are suitable for use in the present invention. These catalysts include the reaction products of phenolic formaldehyde resins with sulfuric acid (Amberlite IR-1, Amberlite IR-100 and Nalcite MX). Also useful are sulfonated resin polymers of coumarone-indene and cyclopentadiene, sulfonated polymers of coumarone-indene and cyclopentadiene, and sulfonated polymers of furfural and cyclopentadiene and furfural. Most suitable cation exchange resins are strongly acid exchange resins consisting essentially of sulfonated polystyrene resins. These resins are prepared and sold commercially under various brand names such as Dowex 50, Nalcite HCR and Amberlyst 15. As obtained commercially, they have a solvent content of about 50% and can be used as is or remove the solvent first. The particle size of the resin is not particularly important and is selected according to the operational advantages associated with any particular size. In general, 10-50 mesh sizes of the US sieve series are suitable. The reaction can be carried out in a stirred slurry reactor or in a fixed bed continuous flow reactor. The catalyst concentration in the stirred slurry reactor should be sufficient to provide the desired catalytic effect. Generally, the catalyst concentration should be 0.5 to 50% by weight (based on dry conditions) of the reactor content, with 1 to 25% being in a suitable range.

Acid ion exchange resins such as Rohm Haas Amberlyst 15 and Dow Chemical Dowex M-31 are currently the most suitable catalysts for etherification.

Referring now to FIG. 1, there is schematically shown an etherification process system 10 having a first reaction section 12, a second reaction section 14, and an alcohol recovery section 16. Preferably, an alcohol feed stream containing methanol is introduced into the etherification process system 10 by conduit 18. A hydrocarbon feed stream containing isobutylene or isoamylene, or both reactive isoolefins and non-reactive diluents is charged to the etherification process system 10 through conduits 20. The two streams that pass through conduits 18 and 20 are mixed together by conduit 22 before being sent to the first etherification reactor vessel 24, which vessels contain the acidic ion exchange resin catalyst described herein. The first etherification reaction zone is partitioned. The first etherification reaction zone is subjected to suitable etherification reaction conditions to react the alcohol contained in the feed stream to the first etherification reactor vessel 24 with at least some tertiary olefins to produce a first etherification reactor effluent. It works.

The first etherification reactor effluent comprises a first stream comprising ether resulting from the reaction taking place in the first etherification reactor vessel 24, unreacted alcohol, unreacted tertiary olefin, and first etherification reactor. Under the etherification reaction conditions under which vessel 24 operates, towards the first separation means 28 for separating the feed into a second stream containing at least a significant amount of compound contained in the inflowed hydrocarbon feed stream that is non-reactive. Is sent through conduit 26. The first separation means 28 may suitably be a device or a process capable of separating ether compounds from a stream comprising primary alcohols and hydrocarbon compounds, although the first separation means 28 define a separation zone and a rectification zone. And a typical conventional distillation column, which may consist of a stripping zone. In the novel process described herein, the first separation means 28, or, where appropriate, the first distillation column or the first fractionator, allows the first etherification reactor effluent to conduit 30 as primary alcohol and overhead flow. Will be separated into an overhead stream containing hydrocarbons sent to the second etherification reactor vessel 32, and a bottom stream containing the first ether product carried from the separator 28 through the conduit 33. .

The second etherification reactor vessel 32 defines a second etherification reaction zone having an acidic ion exchange resin catalyst of the same type used in the first etherification reaction zone. A heat exchanger 34 is fitted in the conduit 30 that defines a heat transfer zone used to remove heat energy from the overhead flow leaving the first separating means 28. The second etherification reactor effluent stream leaves the second etherification reactor vessel 32 through conduit 36. At least a portion of the second etherification reactor effluent stream is sent to conduit 46 to first separation means 28. After at least a portion of the second etherification reactor effluent stream is sent to the first separation means 28, preferably as feed, and most preferably as reflux, the remainder of the second etherification reactor effluent stream is The conduit 38 is sent to the second separating means 40. The second separation means 40 comprises a second portion of the second etherification reactor effluent stream comprising an ether product produced by the reaction of the primary alcohol with the tertiary olefin in the second etherification reactor vessel 32. May be any suitable means for separation into three streams and other streams including hydrocarbons, primary alcohols and by-products generated in the two previous etherification reaction zones. However, it is preferred that the second separation means 40 is a conventional midstream column or fractionator defining a separation zone. In the use of a suitable distillation apparatus, the bottom product from the second separation means 40 will comprise the ether compound produced in the second etherification reactor vessel 32, which product is passed through the conduit 42 to the second product. Leaving the separation means (40). The overhead stream from the second separation means 40 is sent to the alcohol recovery section 16 by unreacted hydrocarbons, primary alcohols, and conduits 44 where the alcohol compounds are separated therefrom. And other undesirable reaction byproducts such as ethers.

The remainder of the second etherification reactor effluent not fed or fed to the first separating means 28 is fed to the second separating means 40 by conduit 38. If the first separation means 28 is in the form of a conventional distillation column, at least a portion of the second reactor product may be fed at any location along the column, but at least a portion of the second etherification reactor effluent is used as the reflux stream. It is preferable to use. An essential feature of the invention is that for the present invention to provide the advantages of high tertiary olefin conversion and low energy consumption, a second etherification reactor vessel 32 must be intervened in the reflux loop of the first fractionator 28. It has been found that at least a portion of the second etherification reactor effluent should be sent to the first fractionator 28. Therefore, the present invention is broad enough to include the use of at least a portion of the second etherification reactor effluent as feed anywhere along the distillation column used as the first separation means 28, while the second etherification reactor effluent It is highly desirable that at least a portion be used as reflux to the first fractionator 28.

The overhead flow from the second separating means 40 is directed to the contacting means 50 to contact the solvent or extracting solvent having the overhead flow which is supplied to the contacting means 50 by the conduit 44. The contacting means 50 may in this case be any suitable device for contacting the solvent with a feed solution containing a solute which is an alcohol, preferably the contacting means 50 will be a contacting vessel defining a contacting zone, Trays or packings may be mounted to assist in intimate contact of the solvent with the solvent.

The contacting means 50 produce an extract residue stream that is substantially free of alcohol, and an extract stream that contains an alcohol rich solvent. Extraction waste stream is removed as an overhead stream from the contact means 50 to separate the extraction residue stream into a stream comprising an oxide which is mainly dimethylether and a stream comprising hydrocarbon by conduit 52 ( 54). The third separation means 54 may be any device suitable for separating an extraction manure stream comprising an oxidizing compound and a hydrocarbon compound, but preferably the third separation means 54 is a distillation column or It is a fractionator. Overhead flow from the third separating means 54 is sent along the flow by the conduit 56 and the bottom flow from the third separating means 54 is sent along the flow by the conduit 58.

The extraction stream from the contacting means 50 is the solvent used to recover the primary alcohol from the primary alcohol-rich feed stream introduced into the contacting means 50. An extract stream comprising a primary alcohol-rich solvent is sent through conduit 60 to a fourth separation means 62, where the fourth separation means transfers the primary alcohol-rich extract solvent to an alcohol stream and a recovery solvent stream with less primary alcohol. To separate. The fourth separating means 62 may be any device suitable for separating the primary alcohol from the solvent added to it, and preferably will be a conventional distillation column or fractionator separating the separation zone. The overhead from the fourth separating means 62 is separated alcohol and leaves the fourth separating means 62 through the conduit 64. Recovered solvent with less primary alcohol is recycled through conduit 66 to contacting means 50 and used as solvent for contacting means 50.

Another embodiment of the present invention is shown in FIG. 2, which shows a second reaction zone 100 having a flow explanatory diagram that is slightly different from that shown in FIG. 1 with respect to the second reaction zone 14. The distinction between the second reaction section 14 and the second reaction section 100 is characterized in that the bottom stream from the second separation means 40 is not sent along the flow for storage or further processing, instead of the separation means. Is recycled to the first separation means 28 via conduit 102 as a feed to the separation zone defined by 28 and preferably as a feed to the stripping zone of the separation means 28. . The use of this bottoms stream as feed to the first separation means 28 allows for a significant amount of cyclopentene entering the etherification process system 10 by hydrocarbon feed into the first reaction section 12. It provides several important advantages over other alternative flow charts in that it helps to remove from the. This is a desirable advantage in that it removes cyclopentene in this process step, thereby preventing it from passing through with the extraction residue stream of the alcohol recovery section 16. Cyclopentene is an undesirable compound for the flow alkylation process and, if not removed prior to passing with the extracting off stream, will eventually be in the hydrocarbon stream passing the process along the flow by conduit 58. An additional advantage of the embodiment shown in FIG. 2 is that the bottoms flow from the second separation means 40 can be sent to the first separation means 28 as a high temperature flow, which can add to the additional boiling heat that may be required for fractionation. It can be used to provide. In other words, when a distillation method is used for the first separating means 28 and the second separating means 40, the bottom flow from the second separating means 40 as a feed to the first separating means 28. The use provides heat concentration of the two distillation columns to lower the overall energy costs associated with the preparation of ether compounds by the novel etherification process system 10.

Another embodiment of the present invention is shown in FIG. 3, where a third type of second etherification reaction section 10 is shown. The second reaction section 110 is similar to the second reaction section 14 under some significant differences. The first difference from the second reaction zone is that substantially all of the reactor effluent leaving the second etherification reactor vessel 32 is sent to the second separation means 40 and any of the reactor effluent is sent to the first separation means. It is not lost. The bottom product from the second separating means 40 is also sent to the first separating means 28 by conduits 42 and 112 as reflux when the first separating means 28 is a conventional separator. Used. Before supplying the bottom flow to the first separating means 28 as reflux, a heat exchanger 114, which is used to cool the flow from the second separating means 40, is fitted in the conduit 112. Heat exchanger 114 defines a heat transfer zone for indirect transfer of thermal energy from the bottom stream to the refrigerant.

The following examples are presented as additional explanation of the invention.

Example I

The following calculations show the benefits that can be obtained from the novel process shown in FIG. 1 when compared to similar processes, and those that do not have the improvements included in the invention of this process are disclosed in US Pat. No. 3,979,461. The comparative process differs from the process of the present invention in that it does not have a second reaction zone in the reflux loop of the first midstream tower of the two reactor stage etherification processes. Table 1 shows the composition of the feed stream for the TAME etherification process, and Table 2 provides relevant process information for both processes, including information such as tertiary olefin conversion through the pre-process and energy requirements for the separation tower for each process. to provide. In addition, data on the MTBE manufacturing process is provided in Tables 3 and 4. Table 3 shows the composition of the feed stream used for the present invention and the comparative process in the MTBE preparation. Table 4 provides relevant process information, including tertiary olefin conversion and process energy requirements for the present and comparative processes.

As can be seen from the data presented in Table 2, a significant improvement in the isoamylene conversion was achieved by the process of the invention with an improvement in the isoamylene conversion from 82.5% to 92.5% by weight. This nearly 10% by weight improvement in isoamylene conversion is a surprising result of using a second etherification reactor in the reflux loop of the distillation column of the etherification process, which is also at least part of the second etherification reactor effluent. As reflux to the middle tower. In general, one of ordinary skill in the art would have predicted that there would be little difference between placing the etherification reactor outside the reflux loop of the process and conversely within the reflux loop of the first fractionator of the process. The data presented for the MTBE production method demonstrate that the process of the present invention can be used in the MTBE production mode as well as in the TAME production mode without any negative impact on the process, yield and tertiary olefin conversion. Due to the ability of the process of the invention to operate in both TAME and MTBE modes of production, one of the objectives of the process of the invention is additionally achieved.

Example II

This calculated embodiment shows several advantages that can be obtained from alternative embodiments of the inventive process. Table 5 provides the process data evaluated for the process of the present invention in the TAME preparation for both the basics of the present invention, namely the first embodiment and the second embodiment of the invention shown in FIG. The evaluation data presented in Table 5 are similar to those shown in Table 1 above, but are based on different feed compositions, with an important difference in composition being the non-reactive component.

The data presented in Table 5 indicate that, as mentioned above, there is a significant advantage by using an alternative process to reduce the amount of cyclopentene in the extract residue product. This is evidenced by the data under the heading of Product C. The C product stream is the stream that will eventually be released into the cyclopentene unless it is first removed from the feed stream to the alcohol recovery section of the process. As previously indicated here, the presence of high concentrations of cyclopentene in the feed stream can negatively affect the process along the stream, so that any nonether compound is added to the alcohol recovery section before the ether product of the process of the present invention. It may be desirable to remove cyclopentene with flow. The data indicate that the alternative process is very effective in removing cyclopentene from the system, as indicated by the cyclopentene volume% in the C product which is significantly reduced under the alternative process.

Claims (28)

By passing the first etherification reactor effluent as a first feed to the first separation means, the feed is passed through a first stream consisting of the first ether product, and unreacted alcohols, tertiary olefins and other non-reactive Separating into a second flow consisting of a compound; Passing the second stream through a reactor zone having an acidic ion exchange resin therein such that the alcohol and tertiary olefins of the second stream react to form a second ether product included in the second reactor effluent stream; Passing a portion of the second reactor effluent stream as a second feed to the first separation means; By passing the remainder of the second reactor effluent stream to a second separation means, the remainder of the reactor effluent stream is a third flow comprising a second ether product, and unreacted alcohol, tertiary olefins and An etherification process comprising reacting a primary or secondary alcohol with a tertiary olefin, comprising separating into a fourth flow comprising another non-reactive compound. The process of claim 1 wherein said portion or all of said second reactor effluent is passed as reflux to said first separating means. The process of claim 1 comprising passing said third stream as said third feed to said first separating means. The process of claim 1 wherein said first separating means comprises a rectifying zone and a stripping zone. By passing the first etherification reactor effluent to a first separation means having a rectifying zone and a stripping zone as the first feed, the feed is passed through a first stream comprising the first ether product, and unreacted alcohol, tertiary. Separating into a second stream comprising olefins and other non-reactive compounds; Passing the second stream through a reactor zone having an acidic ion exchange resin therein such that the alcohol and tertiary olefins of the second stream react to form a second ether product included in the second reactor effluent stream; By passing the second reactor effluent stream through a second separation means, it is separated into a third stream comprising a second ether product and a fourth stream comprising unreacted alcohol, tertiary olefins and other non-reactive compounds. and ; Etherification process consisting of reacting primary or secondary alcohols and tertiary olefins, comprising passing the third stream as a second feed to the stripping zone of the first separation means to provide backboiling heat. 6. The process according to claim 5, comprising cooling the third flow to produce a cooled flow and using the cooled flow as reflux to the first separation means. The process of claim 5 or 6, wherein the non-reactive other compounds comprise a hydrocarbon. 7. Process according to claim 5 or 6, comprising sending the fourth flow to an alcohol recovery system to recover alcohol from the fourth stream. The process of claim 8, wherein the fourth stream in the alcohol recovery system is contacted with a solvent in a contacting zone to produce an extraction stream comprising an extraction manure stream and the alcohol-rich solvent. 10. The process of claim 9, comprising separating the extraction off stream into a fifth stream comprising oxides and a sixth stream comprising hydrocarbons. 11. The process of claim 10, further comprising separating the extract stream into a seventh stream comprising alcohol and an eighth stream comprising the solvent with little alcohol. 12. The process of claim 11 further comprising using said eighth stream as said solvent in said contact zone. 12. The first etherification reactor effluent according to claim 11, wherein the first etherification reactor effluent comprises a hydrocarbon feed stream comprising tertiary olefins and other non-reactive compounds and an alcohol feed stream comprising alcohol in the first etherification zone. A process prepared by contacting an acidic ion exchange resin under etherification conditions. The process of claim 13 comprising mixing the seventh stream with the alcohol feed stream. The process according to claim 5 or 6, comprising reacting the primary alcohol with a tertiary olefin. The method of claim 15, wherein the tertiary olefin comprises isoamylene, the primary alcohol comprises methanol, and the first etherification reactor effluent is methyl tertamyl ether, and unreacted isoacyl. Process comprising millene and methanol. The method of claim 15, wherein the tertiary olefin comprises isobutylene, the primary alcohol comprises methanol, and the primary etherification reactor effluent is methyl tertiary butyl ether, and unreacted isobutylene And methanol. The process according to claim 1, 2, 3 or 4, wherein the other non-reactive compounds comprise hydrocarbons. 5. The process according to claim 1, 2, 3 or 4 comprising recovering alcohol from the fourth flow by blowing the fourth flow into an alcohol recovery system. 6. 20. The process of claim 19, wherein said fourth stream in said alcohol recovery system is contacted with a solvent in a contacting zone to produce an extract stream comprising an extract residue stream and said alcohol enriched solvent. 21. The process of claim 20, comprising separating the extract residue stream into a fifth stream comprising oxides and a sixth stream comprising hydrocarbons. The process of claim 21, further comprising separating the extract stream into a seventh stream comprising alcohol and an eighth stream comprising the solvent with little alcohol. The process of claim 22 further comprising using the eighth stream as the solvent in the contacting zone. 23. The first etherification reactor effluent according to claim 22, wherein the first etherification reactor effluent comprises a hydrocarbon feed stream comprising tertiary olefins and other non-reactive compounds and an alkyle feed stream comprising alcohols within the first etherification zone. A process prepared by contacting an acidic ion exchange resin under etherification conditions. The process of claim 24 comprising mixing the seventh flow with the alcohol feed stream. The process according to claim 1, 2, 3 or 4, comprising reacting the primary alcohol with a tertiary olefin. 27. The method of claim 26, wherein the tertiary olefin comprises isoamylene, the primary alcohol comprises methanol, and the first etherification reactor effluent is methyl tertamyl ether, and unreacted isoacyl. Process comprising millene and methanol. 27. The method of claim 26, wherein the tertiary olefin comprises isobutylene, the primary alcohol comprises methanol, and the primary etherification reactor effluent is methyl tertiary butyl ether, and unreacted isobutylene And methanol.