MXPA01008397A - Catalytic conversion of oxygenates to olefins - Google Patents

Abstract

A method for converting oxygenates to light olefins. The method comprises the steps of (a) contacting, in a reactor, a feedstock containing one or several oxygenates, with a molecular sieve catalyst under conditions effective to form a product containing one or several light olefins and by-products, said contacting causing carbonaceous deposits to form on at least a portion of said molecular sieve catalyst, thereby producing deactivated catalyst;(b) removing a portion of said deactivated catalyst from said reactor;(c) regenerating said portion of said deactivated catalyst to remove at least a portion of said carbonaceous deposits from said deactivated catalyst removed from said reactor, thereby forming an at least partially regenerated catalyst;and (d) exposing at least a portion of said at least partially regenerated catalyst to by-products obtained at step (a).

Description

OXYGENATE CONVERSION REACTIONS Field of the Invention The present invention relates to a method for selectively converting a feed material containing one or more oxygenates using a selective catalyst. It also relates to a method for producing said selective catalyst. Background of the Invention Light olefins, defined herein as ethylene, propylene, and mixtures thereof, serve as feedstocks for the production of numerous important chemicals and polymers. Light olefins are traditionally produced by disintegration (cracking) of petroleum feeds. Due to the limited supply of competitive petroleum feeds, the opportunity to produce low-cost light olefins from petroleum feeds is limited. Efforts have been increased to develop technologies for the production of light olefins based on alternative feeding materials. An important type of alternate feedstocks for the production of light olefins are feedstocks containing one or more oxygenates, such as, for example, alcohols, particularly methanol and ethanol, dimethyl ether, methyl ethyl ether, diethyl ether , dimethyl carbonate, and methyl format. Many of these oxygenates can be produced by fermentation, or from synthesis gas derived from natural gas, petroleum liquids, carbonaceous materials, including coal, recycled plastics, municipal waste, or any organic material. Due to the wide variety of sources, alcohol, alcohol derivatives, and other oxygenates are promising as an economic source, not a source of oil, for the production of light olefins. The reaction, which converts oxygenates to desired light olefins, also produces side products. Representative secondary products include, for example, alkanes (methane, ethane, propane, and higher), C4 + olefins, aromatics, carbon oxides. The formation of carbonaceous deposits (also referred to as "coke") on the catalyst is also observed. During the conversion of oxygenates to light olefins, carbonaceous deposits accumulate on the catalysts used to promote the conversion reaction. As the amount of these carbonaceous deposits increases, the catalyst begins to lose activity and, consequently, less feedstock is converted into light olefin products. At some point, the accumulation of these carbonaceous deposits causes the catalyst to reduce its ability to convert oxygenates to light olefins. When a catalyst can no longer convert oxygenates to olefin products, it is considered that the catalyst is deactivated. Once a catalyst becomes deactivated, it must be removed from the reaction vessel and replaced with fresh catalyst. Such a complete replacement of the deactivated catalyst is expensive and time-consuming. To reduce catalyst costs, the carbonaceous deposits are periodically removed in whole or in part from all the catalyst deactivated and / or partially deactivated to allow re-use of the catalyst. Removal of the deactivated catalyst and / or partially deactivated catalyst from the reaction process stream to remove the carbonaceous deposits is typically referred to as regeneration, and is typically conducted in a unit called a regenerator. Previously in the art, catalyst regeneration was achieved by removing the deactivated catalyst from the process stream, removing the carbonaceous deposits from the catalyst, and then returning the regenerated catalyst to the reactor near the reactor inlet or reaction vessel. Conventionally, this inlet is located near the bottom quarter of the reactor or reaction vessel. Returning the regenerated catalyst near the reactor inlet, the regenerated catalyst would make immediate contact with fresh feed material and start the conversion of the feed material. However, doing this has nothing to control the conversion of the feed material into by-products. For example, US Patent No. 4,873,390, issued to Lewis et al, teaches a process for catalytically converting a feedstock into a product in which the feedstock is contacted with a partially regenerated catalyst. Lewis and co-workers describe that a partially regenerated catalyst improves the selectivity of the process to the light olefin products. Although contacting the feedstock with a partially regenerated catalyst can improve the selectivity of the process to the light olefin products, it does nothing to control the production of by-products. For these reasons, there is a need in the art for improved processes that increase the selectivity to light olefins and control the production of by-products. SUMMARY OF THE INVENTION The present invention solves the current needs of the material by providing a method for increasing the production of light olefins and controlling the production of byproducts and carbonaceous deposits on the catalyst. One aspect of the present invention is directed to a method for producing a selective catalyst. As used herein, the word "selective" (or selective) refers to a process by which a certain amount of carbonaceous deposits is formed on the catalyst to cause the catalyst to produce more ethylene and propylene from the feed of oxygenates and produce fewer secondary products. In the present invention, the selectivation of the catalyst occurs by contacting the catalyst with the by-products of the conversion reaction. However, the light olefins produced by the oxygenate conversion reaction can also be used for the catalyst selectivity, either separately or in combination with the by-products. As will be appreciated by one skilled in the art, it is preferred that as many by-products as possible select the catalyst and as few light olefins as possible select the catalyst. While the by-products make contact with an at least partially regenerated catalyst, the portion of C4 + olefins mainly from the side products is converted mainly into light olefins and carbonaceous deposits which are formed on the catalyst. Although the accumulation of the carbonaceous deposits contributes to the deactivation of the catalyst, the accumulation of the carbonaceous deposits also contributes to the selection of the catalyst. When the selective catalyst contacts the oxygenate feed, the selectivity of the conversion reaction to form light olefins, particularly ethylene and propylene, is increased, and / or the formation of byproducts and / or the formation of carbonaceous deposits is reduced. the catalyst, compared to using a fresh or regenerated catalyst that has not been screened in accordance with the present invention. The method for selecting the catalyst comprises the steps of (a) contacting, in a reactor, a feed material containing one or more oxygenates, with a molecular sieve catalyst, under conditions effective to form a product containing one or several light olefins and by-products, said contact causing carbonaceous deposits to form on at least a portion of said molecular sieve catalyst, thereby producing deactivated catalyst; (b) removing a portion of said deactivated catalyst from said reactor; (c) regenerating said portion of said deactivated catalyst to remove at least a portion of said carbonaceous deposits from said deactivated catalyst removed from said reactor, thereby forming an at least partially regenerated catalyst; and (d) exposing at least a portion of said at least partially regenerated catalyst to the side products obtained in step (a). In this process, the at least partially regenerated catalyst can also be exposed to one or more light olefins to selectively catalyze the at least partially regenerated catalyst to the formation of light olefins. This process may also include the step of contacting at least a portion of the at least partially regenerated, selective catalyst, ie the catalyst obtained in step (d), with the feed material containing one or more oxygenates. This step and step (d) can be conducted simultaneously. Another aspect of the present invention is directed to a method for converting oxygenates to light olefins. The method comprises contacting, in a reactor, a feed material containing one or more oxygenates with a molecular sieve catalyst that has been screened in accordance with the present invention. The feed material is contacted with the selective catalyst under conditions effective to convert said feed material to a product containing one or more light olefins. This method may include the additional step of recovering the light olefins. If the light olefins are recovered, then this method can also include the step of polymerizing the light olefins to form polyolefins. Yet another aspect of the present invention is directed to a method for reducing the heat of reaction in a reactor by displacing the exothermic conversion of a feedstock during a catalysed chemical conversion process. The method comprises contacting, in a reactor, a feedstock with a catalyst under conditions effective to form a product and by-products, the contact causing carbonaceous deposits to form on at least a portion of the catalyst, causing at least one catalyst portion becomes deactivated catalyst; removing at least a portion of the catalyst deactivated from the reactor; regenerating the portion of the deactivated catalyst removed from the reactor to remove at least a portion of the carbonaceous deposits from the deactivated catalyst to form a catalyst at least partially regenerated; and contacting the at least partially regenerated catalyst with the by-products to facilitate an endothermic reaction with the by-products. Other uses and advantages of the process of the present invention will be apparent from the following detailed description and the appended claims. Detailed Description of the Invention When oxygenates are converted to light olefins, it is desirable to maximize the production of light olefins, and to control, typically to minimize, the production of side products and the formation of carbonaceous deposits on the catalyst. The present invention achieves this result by subjecting at least a portion of a catalyst at least partially deactivated to at least partial regeneration and introducing the at least partially regenerated catalyst into the conversion reactor so that the at least partially regenerated catalyst contacts at least a portion of the by-products of the oxygenate conversion reaction before the catalyst is contacted with the fresh feed of oxygenates. Selectively making the catalyst to form light olefins and causing the overall product to produce fewer by-products. The process of the present invention for converting oxygenates to light olefins employs an initial organic material (feedstock) that desirably comprises one or more oxygenates. As used in this, the term "oxygenates" is defined to include, but is not necessarily limited to, aliphatic alcohols, ethers, carbonyl compounds (aldehydes, ketones, carboxylic acids, carbonates, and the like), and mixtures thereof. The aliphatic fraction desirably should contain in the range of 1 to 10 carbon atoms, and more desirably in the range of 1 to 4 carbon atoms. Representative oxygenates include, but are not necessarily limited to, lower aliphatic, straight-chain or branched alcohols, and their unsaturated counterparts. Examples of suitable compounds include, but are not necessarily limited to: methanol; ethanol; n-propanol; isopropanol; C4-C10 alcohols; methyl ethyl ether; Dimethyl ether; diethyl ether; diisopropyl ether; methyl format; formaldehyde; dimethyl carbonate; methyl ethyl carbonate; acetone; and its mixtures. Desirably, the oxygenates used in the conversion reaction are methanol, dimethyl ether, and mixtures thereof. More desirably, the oxygenate is methanol. As used herein, the term "oxygenate" designates only the organic material used as feed. The total charge of feedstock to the reaction zone may contain additional compounds, such as diluents. In the present invention, a feed material containing one or several oxygenates is contacted in a reaction zone of a reactor with a molecular sieve catalyst under effective process conditions to produce light olefins, i.e. a temperature, a pressure, a WHSV ^^ (space hourly speed in weight) effective and, optionally, 0 an effective amount of diluent, correlated to produce light olefins. These conditions are described in detail later. Usually, the feed material containing one or more oxygenates is contacted with the catalyst when the oxygenates are in a vapor phase. Alternatively, the process can be carried out in a liquid or a mixed vapor / liquid phase. When the process is carried out in a liquid phase or mixed vapor / liquid phase, they can ^^ having resulted in different conversions and selectivities of the feedstock to the product, depending on the catalyst and the reaction conditions. As used herein, the term "reactor" includes not only commercial scale reactors but also pilot size reactor units and laboratory bench scale reactor units. In a stable state or a semi-stable state in the reactor, typically a mixture of a partially deactivated catalyst fraction, a deactivated catalyst fraction, and a partially or fully regenerated catalyst fraction is present in the reactor. As used herein and in the claims, the term "deactivated" includes both a partially deactivated catalyst and a fully deactivated catalyst. In order to form a desired catalyst mixture, a portion of the catalyst deactivated from the reactor, separated from products, is removed and sent to the regenerator. In the regenerator, the carbonaceous deposits are removed from the catalyst. Although it is theoretically possible to remove all carbonaceous deposits from the catalyst, such activity may not be practical due to time constraints and the costs of continued regeneration. For these reasons, as many carbonaceous deposits are removed from the catalyst as possible. In other words, the catalyst is at least partially regenerated. However, desirably, the catalyst is regenerated as fully and completely as practical. The rest of the deactivated catalyst remains in the reactor. Desirably, a portion of the catalyst is removed from the reactor for regeneration and recirculation back to the reactor at the rate of 0.1 to 10 times, desirably 0.2 to 5 times, and most desirably 0.3 to 3 times the feed rate total of oxygenate feed material to the reactor. It has been found in the present invention that the use of an at least partially regenerated catalyst provides improved selectivity to light olefins with a reasonable catalyst activity, and provides better control of the reaction temperature within the reactor than the state processes of the technique. In the present invention, the amount of coke residue or carbonaceous deposits remaining on the catalyst after partial regeneration ranges from 0.1 to 95% by weight, desirably from 0.5 to 85% by weight, and even more desirably from 1 to 65% by weight of the original amount of coke residue or carbonaceous deposits present on the deactivated catalyst. The catalyst can also be fully regenerated. For the purposes of this application, the phrase "fully regenerated" means that no more than 0.1% by weight of the carbonaceous deposits remain on the catalyst. The regeneration temperature in the catalyst regenerator varies from 250 to 750 ° C and desirably from 300 to 700 ° C. Desirably, the catalyst regenerator includes a catalyst separator, desirably a plurality of cyclonic devices, to separate the flue gases from the catalyst. Desirably, the regeneration is carried out in the presence of a gas comprising oxygen or other oxidants. Examples of other oxidants include, but are not necessarily limited to, 02, 03, S03, N20, NO, N02, N205, and mixtures thereof. Air and air diluted with water vapor, nitrogen and / or C02 are desired regeneration gases. Desirably, the oxygen concentration in the regenerator is reduced to a controlled level to minimize overheating or the creation of hot spots in the spent or deactivated catalyst. The deactivated catalyst can also be regenerated reductively with hydrogen, carbon monoxide, mixtures of hydrogen and carbon monoxide, or other suitable reducing agents and gases. Depending on the other parameters of the oxygenate conversion reaction and the feedstock, a combination of an oxidative regeneration and a reductive regeneration can be employed. Before the deactivated catalyst is at least partially regenerated, in a particularly oxidatively regenerated manner, at least some of the volatile organic compounds are desirably stripped of the catalyst in a stripping or stripping chamber, using steam, nitrogen, or methane , among others. Stripping the catalyst can improve the economy of the process, the operation of the process and / or the control of emissions. If the organic compounds are not removed, they will provide more fuel value. With the withdrawal, the recovered organic compounds may have a higher value as chemical products, not as fuels. In addition, the amount of organic compounds removed during regeneration or partial regeneration is reduced. This leads to better heat management in both the catalyst regenerator and the catalyst, particularly when the oxidative regeneration method is used. Less carbon oxides are generated in an oxidative regeneration mode because there are fewer organic compounds to be removed oxidatively. After being regenerated, and optionally stripped, the at least partially regenerated catalyst is exposed to at least the by-products of the conversion reaction. In combination with being exposed to the by-products, the at least partially regenerated catalyst may also be exposed to the light olefins produced by the conversion reaction. This exposure occurs either in the reactor or in a vessel separate from the reactor. Before being exposed to the oxygenate feedstock, the at least partially regenerated catalyst fraction contacts, at an appropriate concentration and / or partial pressure, the by-products, and optionally the light olefins, for a sufficient period of time and / or under effective conditions to selectively select the regenerated catalyst. This initial contact with the byproducts, and optionally the light olefins in combination with the side products, can occur either inside or outside the reactor. Desirably, the initial contact is achieved by sending the at least partially regenerated catalyst, at a suitable temperature, to a location in the reactor containing mostly by-products, and optionally an amount of the light olefins. This portion of the reactor may also contain the non-regenerated, deactivated portion of the catalyst, an amount of the unreacted oxygenate feed, or a combination of both. This contact with the by-products, and optionally the products of the conversion reaction, serves to selectively catalyze the at least partially regenerated catalyst to the formation of light olefins. The selective catalyst is then mixed with the rest of the catalyst at least partially deactivated to form a mixture of the non-regenerated catalyst and the selective catalyst, followed by contact of the catalyst mixture with the feed material. Desirably, the at least partially regenerated catalyst is returned on contact with the by-products, and optionally the light olefins, when the at least partially regenerated catalyst is hot. By "hot" it is meant that at least the regenerator catalyst is not cooled below the temperature of the catalyst that is already in the reactor before being contacted with the secondary products, and optionally the products. For example, the catalyst that is being returned from the regenerator will have a temperature of 250 to 750 ° C. A person skilled in the art will appreciate that a slight amount of cooling can take place as the regenerator catalyst is transferred to the reactor. Hot catalyst can be used because the at least partially regenerated catalyst is not initially making contact with the entire amount of oxygenate feedstock, but instead the products of the converted feedstock and higher temperatures can be used to facilitate the conversion of C4 + olefins. One skilled in the art will appreciate that the at least partially regenerated catalyst will make contact with some unconverted feed but not sufficient contact with the pure feed to reduce the beneficial effects of contacting the at least partially regenerated catalyst with the side products. ^^ The oxygenate conversion reaction of the present invention can be conducted in a fluidized bed reactor having an elevator (or lift region) and a dense fluid bed section (or dense phase region). Typically, the dense phase region is located on the lifting region. When this type of reactor is used, the at least partially regenerated catalyst is returned to one of the following places in the reactor: over the dense phase region; immediately below the dense phase region; or anywhere between about the fourth upper part of the lifting region and the dense phase region, desirably between about the upper fourth of the lifting region and about the fourth lower part of the heavy phase region. In another embodiment of the process of the present invention, the contact between the by-products, and optionally the light olefins or a mixture thereof, of the oxygenate conversion reactor and the at least partially regenerated catalyst fraction, to selectively catalyze the catalyst , can occur in a separate container outside the reactor. The temperature, pressure, time period, and other reaction conditions effective for initial contact are determined by factors that include, but are not necessarily limited to, oxygenate conversion reaction conditions, the amount of residual carbonaceous materials present in the catalyst, the level or degree of at least partial regeneration, the percentage of total coke removed from the deactivated catalyst, the selected oxygenate feed, overall heat integration considerations, and combinations thereof. There is enough flexibility in the selection of parameters to achieve the desired results. Again, it is desirable to contact the catalyst with the products of the conversion reaction while the catalyst is hot. Once the at least partially regenerated catalyst has been screened, the selective catalyst can then be exposed to the feed material containing one or more oxygenates to convert the oxygenates into olefin products and by-products. As noted above, the contact of the oxygenate feedstock with the selective catalyst increases the selectivity of the oxygenate conversion reaction to produce light olefins. In the oxygenate conversion reaction of the present invention, the useful temperature for converting the one or more oxygenates into products varies in a wide range, • depending, at least in part, on the selected catalyst, the fraction of the regenerated catalyst in the catalyst mixture, and the configuration of the reactor. Although not limited to a particular temperature, better results are obtained if the process is conducted at a temperature of 200 to 700 ° C, desirably 250 to 600 ° C, and more desirably 300 to 500 ° C. Lower temperatures generally result in lower reaction rates, and the rate of formation of the desired light olefin products may become markedly slower. However, at higher temperatures, the process may not form an optimum quantity of light olefin products, and the rate of coke formation may become too high. Light olefins are formed, although not necessarily in optimum amounts, over a wide range of pressures, including, but not limited to, autogenous pressures and pressures in the range of 0.1 kPa to 5 MPa. A desired pressure is 5 kPa to 1 MPa, and more desirably 20 kPa to 500 kPa. The above pressures do not include those of a diluent, if any, and refer to the partial pressure of the oxygenate present in the feedstock as it relates to the oxygenates and / or their mixtures. Pressures outside the ranges mentioned may be used and are not excluded from the scope of the invention. The upper and lower pressure ends may adversely affect the selectivity, the conversion, the rate of coke formation, and / or the reaction rate; however, light olefins will still be formed. If desired, the oxygenate conversion reaction can be continued for a period of time sufficient to produce light olefins and / or achieve a stable state of production of light olefin products. It is also desirable to equalize the catalyst regeneration cycle and the oxygenate conversion reaction to achieve the desired catalytic performance, such as maintenance of activity, selectivity to light olefins and control of side products. In addition, a portion of the catalyst can be recirculated in the reactor before it is sent to the regenerator. Because some attrition occurs, a certain amount of replacement catalyst is used to replace the generated and separated fine catalyst particles. A wide range of space hourly rates in weight (WHSV), defined as the feed in weight per hour per weight of catalyst, works with the present invention. The WHSV must be sufficiently high to maintain the catalyst in the fluidized state under the reaction conditions and within the configuration and design of the reactor. Generally, the WHSV is from 1 to 5,000 hr "1, desirably from 2 to 3,000 hr" 1, and most desirably from 5 to 1,500 hr "1. For a feedstock comprising methanol, dimethyl ether, or its mixtures, the WHSV is in the most desirable way in a range of 5 to 300 hr "1. Because the catalyst can contain other materials that act as inert materials, fillers, or binders, the WHSV is calculated based on the weight of the oxygenates in the feed material and the molecular sieve content of the catalyst. One or more diluents can be fed to the reaction zone with one or more oxygenates, such that the total feed mixture comprises diluent in a range of 1 to 99 mol%. Diluents can also be used in connection with recharging the at least partially regenerated catalyst back to the reactor. Diluents that may be employed in the process include, but are not necessarily limited to, water (water vapor), nitrogen, carbon dioxide, carbon monoxide, hydrogen, helium, argon, paraffins, light saturated hydrocarbons (such as methane). , ethanol, and propane), aromatic compounds, and their mixtures. Desired diluents are water (water vapor), nitrogen, and their mixtures. The level of Oxygenate conversion - particularly during a stable state of the reaction - can be maintained to reduce the level of undesirable byproducts. The conversion can also be maintained sufficiently high to avoid the need for commercially unacceptable levels of recycling of unreacted feeds. A reduction in unwanted side products is seen when the conversion moves from 100 to 98 mole% or less. Recycling up to as much as 50 mol% of the feedstock is commercially acceptable. So, the 5 conversion levels that reach both goals are from 50 to 98 mol% and, desirably, from 85 to 98 mol%. However, it is also acceptable to achieve conversion between 98 and 100 mole% in order to simplify the recycling process. The conversion of oxygenates can be maintained at this level using various methods familiar to those skilled in the art. Examples include, but are not necessarily limited to, adjusting one or more of the following: the reaction temperature, the pressure, the flow rate (ie, the velocity space); the level and degree of catalyst regeneration; the amount of recirculation of catalyst; the specific configuration of the reactor; the food composition; and other parameters that affect the conversion. ^^ Fixed beds can also be used to carry out the process of the present invention, but they are less or less desirable because a reaction run of conversion of oxygenates to olefins in such a reactor requires several stages with inter-coolers or others. heat removal devices due to the exothermic characteristic of the reaction. In addition, the oxygenate conversion reaction also results in a high pressure drop in a fixed bed due to the production of low pressure, low density gases. In addition, processes to remove the deactivated catalyst and recharge the at least partially regenerated catalyst are difficult to carry out. Suitable catalysts for catalyzing the conversion reaction of oxygenates to olefins of the present invention include molecular sieve catalysts. The molecular sieve catalysts can be zeolitic (zeolites) or non-zeolitic ^^ (non-zeolites). Useful catalysts can also be formed at 0 from mixtures of zeolitic and non-zeolitic molecular sieve catalysts. Desirably, the catalyst is a non-zeolitic molecular sieve. Desired catalysts for use with the process of the present invention include "small" and "medium" pore molecular sieve catalysts. The "small pore" molecular sieve catalysts are defined as catalysts with pores having a diameter of less than 5.0 Angstroms. The "medium pore" molecular sieve catalysts are ^^ defined as catalysts with pores having a diameter in the range of 5.0 to 10.0 Angstroms. Acid resistance, acidity distribution, and density of acid sites, adjusted appropriately, are also key to a good oxygenate conversion catalyst. Useful zeolitic molecular sieve catalysts include, but are not limited to, mordenite, chabazite, erionite, ZSM-5, ZSM-34, ZSM-48, and mixtures thereof. The methods for making these catalysts are known in the art and do not need to be discussed in the present. Silicoaluminophosphates ("SAPOs") are a group of non-zeolitic molecular sieve catalysts that are useful in the present invention. Processes for making SAPOs useful are known in the art. In particular, small pore SAPOs are desired. The SAPO molecular sieves have a three-dimensional micro-porous crystalline framework of tetrahedral units of P02 +, A102", Si02 and Me02m, with or without metals in the framework The super-index" m "represents a net electric charge, depending of the valence state of the substituent, Me. When "Me" has a valence state of +2, +3, +4, +5 or +6, m is -2, -1, 0, +1 and +2, respectively. "Me" includes, but is not necessarily limited to, Zn, Mg, Mn, Co, Ni, Ga, Fe, Ti, Zr, Ge, Sn, Cr, and their mixtures, because an aluminophosphate framework ( A1P04) inherently neutral in electrical charge, the incorporation of silicon or other metallic or non-metallic elements in the framework by substitution generates more catalytically active sites, particularly acid sites, and increased acidity Control the amount and location of silicon atoms and other elements incorporated into a framework of A1P04 is important in determining the catalytic properties of a particular SAPO molecular sieve. SAPOs suitable for use in the invention include, but are not necessarily limited to, SAPO-34, SAPO-17, SAPO-18, SAPO-44, SAPO-56, and mixtures thereof. In a more desired embodiment, the SAPO is SAPO-34. The substituted SAPOs form a class of molecular sieves known as "MeAPSOs", which are also useful in the present invention. Processes for making MeAPSOs are known in the art. The SAPOs with substituents, such as MeAPSOs, may also be suitable for use in the present invention. Suitable "Me" substituents include, but are not necessarily limited to, nickel, cobalt, manganese, zinc, titanium, strontium, magnesium, barium, and calcium. The substituents can be incorporated during the synthesis of MeAPSOs. Alternatively, the substituents can be incorporated after the synthesis of SAPOs or MeAPSOs using many methods. The methods include, but are not necessarily limited to, ion exchange, incipient wetting, dry mixing, wet mixing, mechanical mixing, and combinations thereof. The desired MeAPSOs are small pore MeAPSOs having a pore size of less than 5 Angstroms. Small pore MeAPSOs include, but are not necessarily limited to, NiSAPO-34, CoSAPO-34, NiSAPO-17, CoSAPO-17, and mixtures thereof. The aluminophosphates (ALPOs) with substituents, also known as "MeAPOs", are another group of molecular sieves that may be suitable for use in the present invention, the desired MeAPOs being small pore MeAPOs. Processes for making MeAPOs are known in the art. Suitable substituents include, but are not necessarily limited to, nickel, cobalt, manganese, zinc, titanium, strontium, magnesium, barium, and calcium. The substituents can be incorporated during the synthesis of the MeAPOs. Alternatively, the substituents can be incorporated after the synthesis of ALPOs or MeAPOs using many methods. The methods include, but are not necessarily limited to, ion exchange, incipient wetting, dry mixing, wet mixing, mechanical mixing, and combinations thereof. The catalyst can be incorporated into a solid composition, preferably solid particles, where the catalyst is present in an amount effective to promote the desired conversion reaction. The solid particles may include a catalytically effective amount of the catalyst and the matrix material, preferably at least one of a filler material and a binder material, to provide a desired property or properties, eg, desired catalyst dilution, mechanical strength, and similar, to the solid composition. Such matrix materials are often porous in nature to some extent and often have some non-selective catalytic activity to promote the formation of undesirable products and may or may not be effective in promoting the desired chemical conversion. Such matrix materials, for example fillers and binders, include, for example, synthetic and naturally occurring substances, metal oxides, clays, silicas, aluminas, silica-aluminas, silica-magnesias, silica-zirconias, silica-torias , silica-beryllia, silica-titanium, silica-alumina, silica-alumina-zirconia, and mixtures thereof. The solid particles preferably comprise 1 to 99%, more preferably 5 to 90%, and still more preferably 10 to 80% by weight of catalyst; and an amount of 1 to 99%, more preferably 5 to 90%, and still more preferably 10 to 80% by weight of the matrix material. The preparation of the solid compositions, for example solid particles, comprising the catalyst and the matrix material, is conventional and well known in the art, and is therefore not discussed in detail herein. The present invention will be better understood with reference to the following examples, which illustrate, but are not intended to limit, the present invention. Example 1 A sample of 0.055 g of SAPO-34 catalyst, which had been previously calcined in air at 550 ° C for 16 hours, ^^ was placed between two quartz wool plugs in a quartz reactor tube of 4 mm. diameter. The tube was then inserted into an electrically heated zone, which was directly linked to a gas chromatograph for on-line analysis of the products. The pressure inside the reactor tube was maintained at 16.5 psi (gauge) using a backpressure regulator. The temperature was maintained at 450 ± 2CC. Helium 5 com carrier gas was used at a flow rate of 60 ml / min. Gaseous samples of 1 ml of ethylene (C2 =) were injected successively at 30 minute intervals to the catalyst. The products in the effluent were directed to a gas chromatographic column for analysis. The ethylene conversion was calculated by subtracting from 5 of 100% all the detected gas phase hydrocarbon products other than the ethylene feed itself. The selectivities to the products of interest are shown in Table I. The coke yield was not determined. ^^ Example 2 0 The procedure described in Example 1 was repeated, except that gaseous samples of 1 ml of propylene (C3 =) were used as feeds. The propylene conversion was calculated by subtracting from 100% all the detected gas phase hydrocarbon products other than the propylene feed itself. The selectivities to the products of interest are shown in Table I. Coke yield was not determined. ^^ Example 3 The procedure described in Example 1 was repeated, except that gaseous samples of 1 ml of 1-butene (1-n-C4 =) were used as feed. The conversion of butene-1 was calculated by subtracting from 100% all the gas-phase hydrocarbon products detected other than the butene-1 feed and other butene isomers. The selectivities to the products of interest are shown in Table I. The coke yield was not determined. Example 4 The procedure described in Example 1 was repeated, except that liquid samples of 1 μl of 1-pentene (1-n-C5 =) were used as feed. The conversion of pentene-1 was calculated by subtracting from 100% all detected gaseous hydrocarbon products other than the butene-1 feed and other C5 + compounds. The selectivities to the products of interest are shown in Table I. The coke selectivity was not determined in this example. Example 5 The procedure described in Example 1 was repeated, except that liquid samples of 1 μl of 1-heptene (l-n-C7 =) were used as feed. The conversion of heptene-1 was calculated by subtracting from 100% all detected gas phase hydrocarbon products other than the heptene-1 feed and other C5 + compounds. The selectivities to the products of interest are shown in Table I. The coke selectivity was not determined in this example. Example 6 The procedure described in Example 3 was repeated, except that the reaction temperature was maintained at 500 ° C. The butene conversion was calculated by subtracting from 100% all detected gas phase hydrocarbon products other than the butene-1 feed itself and other butene isomers.

The selectivities to the products of interest are shown in Table 1. The coke selectivity was not determined in this example. Table I * The reaction rates were calculated based on the first order reaction rates and the spaces hourly speed (WHSV) were estimated. Rates are expressed with rates relative to the ethylene reaction rate, which is set to 1, in order to mitigate any potential inaccuracies in the WHSV measurement.

The results in Table I show that ethylene is relatively unreactive under typical oxygenate conversion conditions. The relative reaction rates of converting C3 = to C7 = were at least six times higher than the rate of ethylene conversion. Accordingly, longer chain olefins are preferentially converted to shorter chain olefins when contacted with a non-zeolitic molecular sieve catalyst, such as SAPO-34. When a regenerated catalyst is sent back to the reactor, it is advantageous to expose the regenerated catalyst to the oxygenate conversion products first to further convert heavier olefins to ethylene and / or propylene. This method, in effect, increases the overall yield or selectivity of the desired light olefins and reduces the amount of heavier olefins. Example 6 shows a much higher reaction rate of converting butenes to light olefins by contacting an oxygenate conversion catalyst at a higher temperature without adversely affecting the selectivities to ethylene and propylene. One skilled in the art will also appreciate that the olefins produced by the oxygenate conversion reaction in olefins of the present invention can be polymerized to form polyolefins, particularly polyethylene and polypropylene. Processes for forming polyolefins from olefins are well known in the art. Catalytic processes are preferred. Particularly preferred are the metallocene, Ziegler / Natta and acid catalyst systems. See, for example, US Pat. Nos. 3,258,455; 3,305,538; 3,364,190; 5,892,079; 4,659,685; 4,076,698; 3,645,992; 4,302,565; and 4,243,691, the descriptions of the catalyst and the process of each one being expressly incorporated herein by reference. In general, these methods involve contacting the olefin product with a polyolefin-forming catalyst at an effective pressure and temperature to form the polyolefin product. A preferred polyolefin-forming catalyst is a metallocene catalyst. The preferred operating temperature range is between 50 and 240 ° C, and the reaction can be carried out at low, medium or high pressure, being anywhere within the range of about 1 to 200 bar. For processes carried out in solution, an inert diluent can be used, and the preferred operating pressure range is between 10 and 150 ^^ bars, with a preferred temperature range of between 120 and 230 ° C. For processes in the gas phase, it is preferred that the temperature is generally within a range of 60 to 160 ° C, and that the operating pressure is between 5 and 50 bars. In addition to polyolefins, numerous other olefin derivatives can be formed from the olefins produced by the process of the present invention or olefins recovered therefrom. These include, but are not limited to, aldehydes, alcohols, acetic acid, linear alpha-olefins, acetate ^. vinyl, ethylene dichloride and vinyl chloride, ethylbenzene, ethylene oxide, eumeno, isopropyl alcohol, acrolein, allyl chloride, propylene oxide, acrylic acid, ethylene-propylene rubbers, and acrylonitrile, and ethylene, propylene or Butylenes The methods of manufacturing these derivatives are well known in the art, and therefore are not discussed herein. As mentioned above, the preferred oxygenate for use in the methods of the present invention is methanol. Each of the methods of the present invention may also include the step of forming methanol. The methods to form oxygenates, such as methanol, are known in the art and will not be discussed in detail herein. Two methods for forming oxygenates include fermentation and formation from synthesis gas. These methods are also useful for forming other oxygenates. Also as noted above, the at least partially regenerated catalyst can be used to deliver heat into the conversion reactor. As one skilled in the art will appreciate, the conversion of the oxygenate feedstock into light olefins in an exothermic reaction. By returning the at least partially regenerated catalyst to contact with the by-products of the conversion reaction, the longer chain by-products of the conversion reaction are converted into shorter light chain olefin products. The conversion of the longer chain by-products into shorter chain light olefin products is an endothermic reaction. The conversion of the secondary products into light olefin products consumes the heat produced by the conversion of the oxygenate feed, thereby reducing the overall reaction heat in a reactor during a catalyzed chemical conversion process. By feeding the hot catalyst to the reactor, a catalyst cooler can be removed from the apparatus used to produce the desired olefins or, at least, the catalyst cooler can be reduced in size and / or cooling work. The hot catalyst is cooled in the reactor by the endothermic conversion of the longer chain olefins (C4, C5, C6 and higher) into ethylene, propylene and coke.

Claims (43)

1. CLAIMS 1. A method for producing a selective catalyst, said method comprising: (a) contacting, in a reactor, a feed material containing one or more oxygenates, with a molecular sieve catalyst under effective conditions to form a product containing one or more light olefins and side products, said contact causing carbonaceous deposits to form on at least a portion of said molecular sieve catalyst, thereby producing deactivated catalyst; (b) removing a portion of said deactivated catalyst from said reactor; (c) regenerating said portion of said deactivated catalyst 5 to remove at least a portion of said carbonaceous deposits from said deactivated catalyst removed from said reactor, thereby forming a catalyst at least partially. regenerate; and (d) exposing at least a portion of said at least partially regenerated catalyst to at least a portion of said by-products obtained in step (a). The method of claim 1, wherein, in step (d), said at least partially regenerated catalyst is also exposed to one or more light olefins. The method of any of the preceding claims, wherein step (d) is carried out while said portion of said at least partially regenerated catalyst is hot. 4. The method of claim 3, wherein said portion of said at least partially regenerated, hot catalyst is cooled by an endothermic reaction with said by-products. The method of any of the preceding claims, further comprising step (e) of contacting at least a portion of the catalyst obtained in step (d) with said feed material containing one or more oxygenates. 6. The method of claim 5, wherein steps (d) and (e) are carried out simultaneously. 7. The method of any of the preceding claims, wherein steps (a) and (d) are carried out in a fluidized bed reactor including a lifting region and a dense phase region on said lifting region. The method of claim 7, wherein step (d) is carried out at a point on said lifting region. The method of any one of the preceding claims, wherein the molecular sieve catalyst used in step (a) comprises a small pore non-zeolitic molecular sieve. 10 The method of any of the preceding claims, wherein the molecular sieve catalyst used in step (a) includes a silicoaluminophosphate (SAPO). The method of claim 10, wherein said SAPO is selected from the group consisting of SAPO-11, SAPO-17, SAPO-18, SAPO-34, SAPO-44, SAPO-56, and mixtures thereof. The method of claim 11, wherein said molecular sieve catalyst is SAPO-34. The method of any of the preceding claims ^^, wherein said at least partially regenerated catalyst obtained in step (c) is fully regenerated. 1 . The method of any of the preceding claims, wherein said at least partially regenerated catalyst obtained in step (c) converts from 0.1 to 95% by weight of said carbonaceous deposits. 15. The method of claim 9, wherein said at least partially regenerated catalyst retains 0.5 to 85% by weight of said carbonaceous deposits. 16. The method of claim 15, wherein said at least partially regenerated catalyst conserves from 1 to 65% by weight of said carbonaceous deposits. 17. The method of any of the preceding claims, wherein said portion of said deactivated catalyst is removed from said reactor at a rate of 0.1 to 10 times the total feed rate of the feed material oxygenates to the reactor. 18. The method of claim 17, wherein said portion of said deactivated catalyst is removed from said reactor at a rate of 0.2 to 5 times the total feed rate of the oxygenates of feedstock to the reactor. 19. The method of claim 18, wherein said portion of said deactivated catalyst is removed from said reactor at a rate of 0.3 to 3 times the total feed rate of the oxygenates of feedstock to the reactor. 20. A method for converting a feed material containing one or more oxygenates into one or more light olefins, comprising the step of contacting, in a reactor, a feed material containing one or more oxygenates with a catalyst of Selective molecular sieve, obtainable by the methods of claims 1 to 19, under conditions effective to convert said feed material into a product containing one or more light olefins. The method of any of the preceding claims, wherein the one or more oxygenates contained in the feedstock are selected from the group consisting of methanol; ethanol; n-propanol; isopropanol; C4-C10 alcohols; methyl ethyl ether; Dimethyl ether; diethyl ether; diisopropyl ether; methyl format; formaldehyde; dimethyl carbonate; methyl ethyl carbonate; acetone; and its mixtures. The method of any of the preceding claims, wherein said feedstock containing one or more oxygenates further includes a diluent selected from the group consisting of water, nitrogen, hydrogen, carbon dioxide, carbon monoxide, helium, argon, paraffins, light saturated hydrocarbons, aromatic compounds, and their mixtures. The method of any of the preceding claims, further comprising the step of recovering said one or more light olefins. The method of claim 23, further comprising the step of polymerizing said light olefins to form polyolefins. 25. The method of claim 23, further comprising the step of forming an olefin derivative from said light olefins. 26. The method of any of the preceding claims, wherein said oxygenate is methanol. 27. The method of claim 26, further comprising the step of forming said methanol. 28. A method for improving the selectivity to light olefins in the process for converting oxygenate feedstocks to olefins, comprising: contacting an oxygenate feedstock with a molecular sieve catalyst under effective conditions to produce a feed stream. product comprising C2-C4 olefins; forming carbonaceous deposits on at least a portion of the molecular sieve catalyst, thereby forming a deactivated catalyst; regenerating at least a portion of the deactivated catalyst under effective conditions to remove at least a portion of the carbonaceous deposits from the deactivated catalyst portion, thereby forming a regenerated catalyst; and contacting at least a portion of the regenerated catalyst with at least a portion of the product stream to form a selective catalyst. 29. The method of claim 28, further comprising contacting at least a portion of the selective catalyst with the oxygenate feedstock. 30. The method of claim 28, wherein the oxygenate feedstock is selected from methanol, ethanol, n-propanol, isopropanol; C4-C10 alcohols; methyl ethyl ether; Dimethyl ether; diethyl ether; diisopropyl ether; methyl format; methyl chloride; methyl bromide; Methyl iodide; Ethyl chloride; ethyl bromide; ethyl iodide; formaldehyde; dimethyl carbonate; methyl ethyl carbonate; acetone; n-alkyl halides having n-alkyl groups of from about 3 to about 10 carbon atoms; and its mixtures. 31. The method of claim 30, wherein the oxygenate feedstock comprises methanol. 32. The method of claim 28, wherein the regenerated catalyst has a content of carbonaceous deposits of from about 0.1 to about 95% by weight, based on the content of carbonaceous deposits of the deactivated catalyst. 33. The method of claim 32, wherein the regenerated catalyst has a content of carbonaceous deposits of from about 0.5 to about 85% by weight, with respect to the content of carbonaceous deposits of the deactivated catalyst. 34. The method of claim 33, wherein the regenerated catalyst has a carbonaceous deposit content of from about 1 to about 65% by weight, based on the carbonaceous deposit content of the deactivated catalyst. 35. The method of claim 28, wherein the regeneration is carried out at a temperature of about ™ 250 at around 750 ° C. 36. The method of claim 35, wherein the regeneration is carried out at a temperature of about 300 to around 700 ° C. 37. The method of claim 30, wherein the oxygenate feedstock further comprises from about 1 to about 99% by weight of a diluent. 38. The method of claim 37, wherein the diluent is selected from water, nitrogen, carbon dioxide, carbon monoxide, hydrogen, helium, argon, paraffins, saturated hydrocarbons, aromatic hydrocarbons, and mixtures thereof. 39. The method of claim 38, wherein the diluent comprises water. 40. The method of claim 28, wherein the molecular sieve catalyst has a pore size of about 5 to about 10 Angstroms. ^^ 41. The method of claim 28, wherein the 0 molecular sieve catalyst is selected from SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, its metal-containing forms, and mixtures thereof. 42. The method of claim 41, wherein the molecular sieve catalyst comprises SAPO-34. 43. A method to improve selectivity to light olefins in the process for converting feedstocks ^ P of oxygenates in olefins, comprising: contacting an oxygenate feedstock comprising water and methanol with a silicoaluminophosphate molecular sieve catalyst, at a temperature of from about 200 to about 700 ° C and a space hourly weight in weight of feedstock from about 1 to about 5,000 hr 1, to produce a product stream comprising C2-C4 olefins; forming carbonaceous deposits on at least a portion of the silicoaluminophosphate molecular sieve catalyst, thereby forming a deactivated catalyst; regenerating at least a portion of the deactivated catalyst under effective conditions to remove at least a portion of the carbonaceous deposits from the deactivated catalyst portion, thereby forming a regenerated catalyst; and contacting at least a portion of the regenerated catalyst with at least a portion of the product stream to form a selective catalyst; contacting at least a portion of the selective catalyst with the oxygenate feedstock.