MXPA00010565A - Process for converting oxygenates to olefins with direct product quenching for heat recovery - Google Patents

Abstract

The present invention relates to a process for catalytically converting a feedstock comprising oxygenates to olefins with direct product quenching to increase heat recovery and to improve heat integration.

Description

PROCESS TO CONVERT OXYGENATES IN OLEFINS WITH DIRECT SUCTION COOLING OF THE PRODUCT FOR HEAT RECOVERY Field of the Invention The present invention relates to a process for increasing the efficiency of heat recovery and improving thermal integration with direct sudden cooling of the product in the selective conversion of oxygenates to olefins. Background of the Invention Light olefmas (defined in the present as ethylene, propylene, butenes, and their mixtures) serve as feeds for the production of numerous important chemicals and polymers. The light olefmas are traditionally produced by disintegrating (cracking) petroleum feeds due to limited supply and costs each time In addition to oil feeds, the cost of producing olefmas from petroleum sources has increased gradually. Efforts have been increased to develop and improve olefin production technologies, particularly light olefmas production technologies, based on feedstocks to the Alternatives An important type of alternative feed material for the production of light olefmas is that of oxygenates, such as alcohols, particularly methanol and ethanol, dimethyl ether, methyl ethyl ether, methyl formate and dimethyl carbonate Alcohols can be produced by fermentation, or from synthesis gas derived from natural gas, petroleum liquids, carbonaceous materials , including coal, recycled plastics, municipal waste, agricultural products, or most organic materials. Due to the wide variety of sources of raw materials, alcohols, alcohol derivatives and other oxygenates are promising as a source of non-petroleum feedstock, economical, for olefin production. The conversion of oxygenates into olefms takes place at a relatively high temperature, generally greater than about 50 ° C, preferably greater than about 300 ° C. Because the conversion reaction is exothermic, the effluent typically has a higher temperature than the initial temperature in the reactor. Many methods and / or process schemes have been proposed to deliver the heat of reaction generated from the conversion reaction of the reaction. oxygenates inside the reactor in order to avoid temperature rises and stitches, and thereby reduce the catalyst deactivation rate and reduce the production of undesirable products, such as methane, ethane, carbon monoxide and carbonaceous deposits or coke. It would be extremely useful to have a process that effectively uses the heat of reaction contained in the products that leave the oxygenate conversion reactor, optimize heat recovery, and reduce the overall energy consumption in the conversion of oxygenates into olefins. Such a process is more attractive environmentally, economically and commercially. Compendium of the Invention The present invention contributes a process for converting an oxygenate into olefins with increased heat recovery and heat integration, said process comprising heating a feed material comprising said oxygenate, having a first heat content of a first temperature at a second temperature through a around three stages having successively higher heat contents, contacting said feed material at said second temperature with a catalyst comprising a molecular sieve under conditions effective to produce a deactivated catalyst having carbonaceous deposits and a product comprising said olef as, where said c The molecular sieve comprises pores having a diameter of less than about 10 Angstroms and said product having a third temperature that is greater than said second temperature, suddenly cooling said product with a medium at an initial temperature and in an amount sufficient to form a light fraction. of product and a heavy fraction of product, wherein said light product fraction comprises light olefmas and said heavy product fraction has a final temperature that is greater than said first temperature in at least about 5'C, using said heavy fraction of product to provide heat in one or more of said steps to achieve said higher heat content Brief Description of the Drawing Figure 1 is a flow chart of a preferred embodiment of increase heat recovery in the present invention. Detailed Description of the Invention The present invention provides a process for increasing heat recovery and reducing energy requirements during the conversion of oxygenates into olefins. The process involves taking the mixture of products, including any unreacted feed of oxygenates, from an oxygenate conversion reactor and, without fractionating the products, suddenly cooling the product mixture directly with a suitable medium, preferably water. This type of sudden cooling in the following will be referred to as "direct product direct cooling" Direct product direct cooling removes heat from the product mixture, causing the upper boiling components, such as water and the unreacted oxygenate feed , they condense and form a heavy fraction of product. The heavy product fraction is separated from the light product fraction, comprising gaseous hydrocarbon components such as light olefmas, methane, ethane, propane and butanes. The fraction Heavy product can be further divided into several fractions The heavy fraction of product, or any or all of the various fractions, can be subjected to various techniques or methods to separate the cooled medium suddenly from other components The heavy fraction of product, or any or all the various fractions or streams produced from separations from the quenched medium can be used to supply at least part of the heat necessary to vaporize or otherwise increase the heat content of the oxygenated feedstock, through one to about three stages, before entering the oxygenate conversion reactor to contact the oxygenate conversion catalyst. These steps give the oxygenate feed material a successively higher heat content. Most of the catalysts that are used in oxygenate conversion processes comprise molecular sieves, of both zeolitic (zeolites) and non-zeolitic type. The present invention must achieve many of the desired improvements using substantially any molecular sieve catalyst, regardless of the type of structure or pore size. Preferred molecular sieve catalysts for use in accordance with the present invention comprise "small" pore molecular sieve catalysts. "and" medium "The" small pore "molecular sieve catalysts are defined as catalysts with pores having a diameter of less than about 5%.

Angstroms. "Medium pore" molecular sieve catalysts are defined as catalysts with pores having a diameter in the range of about 5.0 to about 10.0 Angstroms. "Large pore" molecular sieve catalysts are co-porous catalysts having a diameter greater than about 10.0 Angstroms. Generally, large pore molecular sieve catalysts, with additional modifications and / or appropriate treatments, are not preferred catalysts for converting oxygenates to light olefmas. Zeolitic molecular sieve catalysts suitable for use in the present invention, with varying degrees of effectiveness, include but are not necessarily limited to AEI, AFI, CHA, ERI, LOV, RHO, THO, MFI, FER and substituted examples of these types structural, as described in .M. Meier and D.H. Olson, Atlas of Zeoli txc Structural Types (Butterworth Hememan, 3rd edition, 1997), incorporated herein by reference Preferred zeolite catalysts include, but are not necessarily limited to zeolite 3A, zeolite 4A, zeolite 5A (collectively referred to as successive as zeolite A), ZK-5, ZSM-5, ZSM-34, erionite, chabazite, ofretite, silicalite, borosilicates, and their mixtures See Meier and Olson These zeolites can be obtained from many companies and commercial sources such as Mobil, Amoco, UCI, Engelhard, Aldrich Chemical Company, Johnson Matthey Company, Union Carbide Corporation and others. Silicoalumophosphates ("SAPO's") are a group of Non-zeolitic molecular sieves that are useful in the present invention SAPO's suitable for use in the invention include, but are not necessarily limited to SAPO-17,? APO-18, SAPO-34, SAPO-44, and their small pore SAPO's mixtures are preferred to produce light olefms A preferred SAPO is SAPO-34, which can be synthesized according to U.S. Patent No. 4,871, incorporated herein by reference, and Zeolites, vol. 17, pp.l - 2 (1996), incorporated herein by reference? APO-18 can be synthesized according to J Chen et al, Studies on Surface Sciences and Catalysis, Proceed gs of the Tenth International Catalysis Society, vol. 88, pp. 17-31 ( 1994) Substituted silicoaluminophosphates (substituted SAPO's) form another class of non-zeolitic molecular sieves known as "MeAPSO's", which are suitable for use as catalysts in the present invention. MeAPSO's are described in US Pat. Nos. 4,567,029 and 5,126,308, incorporated herein by reference. SAPO's are substituents incorporated after the synthesis may also be suitable for use in the present invention. Suitable substituents, "Me", include but are not necessarily limited to nickel, cobalt, manganese, chrome, iron, zinc strontium, magnesium, barium and calcium Preferred MeAPSO's include, but are not necessarily limited to N? SAPO-17, NiSAPO-34, Co-SAPO-17, Co-SAPO-34, SAPO-17 modified with Sr (SrAPSO- 17), SAPO-18 modified with Sr (SrAPSO-18), SAPO-34 modified with Sr (SrAPSO-34), SrAPSO-44, and mixtures thereof. Different substituents can be incorporated during or after the synthesis of silicoaluminophosphates. Substituted aluminophosphates (ALPO) known as MeAPO's can also be used as non-zeolitic molecular sieve catalysts for the present invention. MeAPO's include, but are not necessarily limited to ZnAPO, ZrAPO, TiAPO, and their mixtures. These molecular sieves can be synthesized in accordance with US Pat. Nos. 4,861,743; 4,567,029; and 5,126,308. Because the catalyst can be used in a variety of oxygenate conversion reactors and / or under a variety of reaction conditions, it can contain binders, fillers or other material to provide better catalytic performance, resistance to attrition, regeneration capacity , and other desired properties for a particular type reactor. When used in a fluidized bed reactor, the catalyst must be capable of fluidizing under the reaction conditions. A catalyst can be further subjected to a variety of treatments to achieve the desired physical, mechanical and catalytic characteristics. Such treatments include, but are not necessarily limited to, calcination, milling, ball milling, grinding, spray drying, hydrothermal treatment with steam at elevated temperatures - from about 400 to around 800 'C-, treatment with acids, treatment with bases, and their combinations. The process for converting oxygenates into olefmas employs an initial organic material - a feedstock - that preferably comprises "oxygenates". As used herein, the term "oxygenates" is defined to include, but is not necessarily limited to aliphatic alcohols, ethers, carbon compounds (aldehydes, ketones, carboxylic acids, carbonates, and the like), and also compounds containing hetero-atoms, such as halides, mercaptans, sulfides, amines, and mixtures thereof The aliphatic fraction preferably must contain in the range of about 1 to 10 carbon atoms and, more preferably, in the range of about 1 to 4 carbon atoms. Representative oxygenates include, but are not necessarily limited to, straight chain or branched lower aliphatic alcohols, their unsaturated counterparts, and their nitrogen, halogen and sulfur analogues. Examples of suitable compounds include, but are not necessarily limited to, methanol; ethanol, n-propanol; isopropanol; C4-C10 alcohols; ethyl ethyl ether; Dimethyl ether; diethyl ether, di-isopropyl ether, methyl mercaptan; Methyl sulfide; methyl amine, ethyl mercaptan, di-ethyl sulfide; di-ethyl amine, ethyl chloride; methyl format; methyl acetate, formaldehyde, di-methyl carbonate; trimethyl orthoformate, dimethyl ketone; n-alkyl amines, n-alkyl halides, n-alkyl sulfides having n-alkyl groups in the range of about 3 to about 10 carbon atoms; and its mixtures. Preferred oxygenate feedstocks include, but are not necessarily limited to, methanol, dimethyl ether, dimethyl carbonate, methyl formate, and mixtures thereof. As used herein, the term "oxygenate" designates only the organic material used as feed. The total feed charge to the reaction zone may contain additional compounds such as diluents. Preferably, the oxygenate feedstock must be vaporized at least partially and contacted in a suitable oxygenate conversion reactor with the selected molecular sieve catalyst under process conditions effective to produce the desired olefms at an acceptable level of conversion. with desired selectivities The temperature employed in the conversion process can vary over a wide range depending, at least in part, on the pressure, the selected catalyst, the reactor configuration, the space velocity hour by weight, and other reaction parameters. Although a particular temperature is not limited, better results will be obtained if the process is conducted at temperatures in the range of about 00 to about 750"C, preferably in the range of about 50 to about 650 'C, and most preferably in the range of about 300 to about 600 'C as the oxygenate feed material is normally stored at room temperatures before being used in the conversion process, the feed material has to be heated to a higher temperature with a much higher heat content, suitable for making contact with the oxygenate conversion catalyst. It is preferred to increase the heat content and / or the temperature of the feed material through one to about three intermediate stages, each stage having a successively higher heat content. Many different streams in the oxygenate conversion process can be adequate sources to provide the heat needed to increase the heat content. These currents, including those derived from the heavy product fraction of the quench tower and the fractionator streams that separate the quench medium from the other components, are described in more detail below. It should be noted that a stream may have a higher heat content after a heat exchange, although it has a lower temperature, resulting mainly from pressure changes and / or phase changes, such as vapopzation of a liquid. Pressure and / or phase changes are necessary for the oxygenate conversion process. The products of light olefmas will be formed -although not necessarily in optimum quantities- in a wide range of pressures, including but not necessarily limited to sub and super-atmospheric pressures and autogenous pressures- in the range from around 1 kPa to around 100 MPa. A preferred pressure is in the range of about 5 kPa to about 50 MPa, most preferably in the range of about 50 to about 500 kPa. The above pressures are exclusive of diluent, if any diluent is present, and refer to the partial pressure of the feedstock as it relates to oxygenates and / or mixtures thereof. Pressures outside the mentioned ranges can be used and are not excluded from the scope of the invention. A steady-state production or semi-stable state of light olefin products can be achieved and / or sustained over a period of time, largely determined by the type of reactor, the configuration of the reactor, the temperature, the pressure, the selected catalyst, the amount of recirculated spent catalyst (if any), the level of catalyst regeneration, the amount of carbonaceous materials left on the regenerated or partially regenerated catalyst, the space speed in weight (WHSV), the amount of sudden cooling medium used, and other relevant characteristics of process design. A broad range of WHSV, defined as the weight of the total oxygenate feed material per hour per weight of catalyst, for the feedstock, will function in the present invention. Depending on the type of reactor, the desired level of conversion, the composition of the Feed material- In addition to other parameters and reaction parameters, the WHSV should generally be in the range of about 0.01 to about 1,000 hr 1, preferably in the range of about 0.1 to about 500 hr L, and with the greatest preference in the range from about 0.5 to about 200 hr 1. As the catalyst may contain other materials that act as inert materials, fillers or binders, the WHSV is calculated only based on the weight of oxygenate and the molecular sieve portion of the catalyst. One or more diluents can be fed to the reaction zone with the oxygenates, such that the total feed mixture comprises diluent in a range of about 1 to about 99 mole%. The diluents that can be employed in the process include, but they are not necessarily limited to helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, parafamies, other saturated hydrocarbons (such as methane, ethane, propane, and mixtures thereof), aromatics, and mixtures thereof. Preferred diluents include, but are not necessarily limited to, water and nitrogen. Conversion of oxygenates must be maintained high enough to avoid the need for commercially acceptable levels of recycling. Oxygenate conversion of 100% is preferred in order to completely avoid recycling. Feeding material. However, a reduction in the undesirable side products is often observed when the level of oxygenate conversion, particularly methanol, is about 98% or less Accordingly, there is usually from about 0 5 to about 50 mole% of unreacted oxygenate in the product stream along with the oxygenate conversion products comprising olefins, water and / or other byproducts It is preferred to recover as much of the unreacted oxygenate as possible, for recycling purposes. In any case, the oxygenate content in the wastewater may need to be reduced to an environmentally acceptable level before the wastewater can Therefore, it is desirable to consider this incomplete oxygenate conversion in the global heat recovery and in the heat integration scheme, ie to optimize heat recovery and heat integration, when a fractionator is used to recover oxygenates without react If the oxygenate conversion level is sufficiently high and / or the recovery of oxygenate without reaction If it is not justified for economic or environmental purposes, then this invention is directed to using the heat directly from the heavy product fraction or any or all of the various fractions in which the heavy fraction of the product can be divided after making contact with the feed of oxygen, the catalyst becomes totally or partially deactivated due to the accumulation of carbonaceous deposits (also called coke) on the catalyst surface and / or within the pores The deactivated catalyst having carbonaceous deposits is separated from the other oxygenate conversion products. Preferably, at least a portion of the deactivated catalyst is separated and removed from the oxygenate conversion reactor in an intermittent, semi-continuous, continuous, or batch mode before the deactivated catalyst is recycled back to the oxygenate conversion reactor and used again, adequate regeneration is carried out on at least a portion of the deactivated catalyst removed to remove at least a portion of the carbonaceous deposits, in the range of from about 0.1 to about 99.9% by weight, preferably should be removed at least about 10% by weight of the carbonaceous deposits. Complete regeneration can also be carried out - 100% by weight removal of the original carbonaceous deposits on all the deactivated catalyst - but it is found that complete regeneration has a tendency to lead to the production of large quantities of undesirable by-products, such as methane and / or hydrogen. Preferably, the regeneration is carried out in the presence of a gas comprising oxygen or other oxidants. Air and air diluted with nitrogen, water vapor, and / or carbon dioxide, are the preferred gases of regeneration. The catalyst regeneration temperature should be in the range of about 250 to about 750 'C, preferably from about 300 to about 700' C.

Almost any type of reactor will provide certain conversions of the oxygenates into olefins. The type of reactor includes, but is not necessarily limited to, fluid bed reactor, riser reactor, bed reactor in motion, fixed bed reactor, continuously stirred tank reactor, hybrids, and combinations thereof. Increased heat recovery and improved heat integration in the present invention can be achieved with almost any type of reactor. A preferred reactor system for the present invention is a circulating fluid bed reactor with continuous or semi-continuous regeneration of catalyst, similar to a modern fluid catalytic disintegrate. Fixed beds can be used, but they are not preferred. Because the oxygenate conversion reaction is highly exothermic, the effluent product of the oxygenate conversion reaction generally has a temperature higher than the temperature of the feed material just before contacting the catalyst. In an embodiment of the present invention, the feed material of the storage tank at a first temperature, and having a first heat content, is heated through several intermediate stages in heat exchangers, to a second desired temperature before to make contact with the oxygenate conversion catalyst. It is preferred to have from one to about three stages of heat exchange for provide currents with successively higher heat contents. Various streams of the oxygenate conversion process at different temperatures and external heat sources, such as water vapor, can be used as heat exchange fluids to increase either the heat content, the temperature, or both, of the feed material Oxygenated After contacting the oxygenate feedstock with the oxygenate conversion catalyst, the effluent product of the oxygenate conversion reaction, which comprises olefma products, is suddenly quenched directly by contacting an oxygenating medium. suitable flash cooling in a sudden cooling tower without first passing through a product fractionation step. Alternatively, the effluent produced can be used to provide heat directly to the oxygenate feed material. The temperature and the heat content of the produced effluent are reduced to intermediate levels later. The effluent produced at this lower temperature and lower heat content is sent to the sudden cooling tower for direct sudden cooling. Compounds in the effluent stream that are gaseous under the conditions of flash cooling are separated from the quench tower as a light fraction of product for recovery and purification of the olefin product. The light product fraction comprises olefins light, dimethyl ether, methane, CO, carbon dioxide, ethane, propane and other minor components such as water and unreacted oxygenate feedstock Compounds in the effluent stream that are liquid or sudden cooling conditions are separated of the quench tower as a heavy fraction of product for heat recovery, and possible division into vain fractions and separation of the quench medium The product heavy fraction comprises byproduct of water, a portion of the oxygenate feedstock without react (except for those oxygenates which are gases under sudden cooling conditions), a small portion of the oxygenate conversion byproducts, particularly heavy hydrocarbons (C5 +), and usually the bulk of the quench medium. Preferably, a means of Sudden cooling is selected from a composition that pe It remains substantially like a liquid under the conditions of sudden cooling, thus minimizing the amount of the sudden cooling medium present in the light, gaseous fraction of product that must undergo more expensive gaseous product processing steps to recover commercially acceptable grades. of light olefin products A preferred means of flash cooling is selected from the group consisting of water and streams which are substantially water With greater Preferably, the flash cooling medium is a stream that is substantially water and is selected from the various fractions of the heavy product fraction of the quench tower The amount of quench medium circulated in the quench tower at a temperature Particular for product that is subjected to sudden cooling should not be greater than necessary to produce a heavy fraction of product leaving the quench tower having a temperature at least about 5'C greater than the first temperature of the feed material Oxygenate of the storage tank In another embodiment, as already discussed, the effluent stream of the oxygenate conversion reactor is used directly as a heat exchanger fluid to supply heat to the oxygenate feed material before it enters the reactor. conversion to make contact with the oxygen conversion catalyst Preferably, the pressure in the quench tower and the temperature of the product heavy fraction effluent are maintained at effective levels for recovery of the greatest quantity and the highest quality of process heat. Most preferably, the difference between the pressure of the product heavy fraction effluent and the pressure at which the feedstock is vaporized is below about 3 < 15 kPa, more preferably below about 207 kPa La Effluent temperature of product heavy fraction of the quench tower is preferably maintained at not less than about 30 'C below the bubble point of the product heavy fraction effluent Maintain a temperature differential between the effluent fraction product and its bubble point provides the highest possible temperature of the queues in the tower of sudden cooling and the most economically practical recovery of useful heat of the effluent of heavy fraction of product Preferably, the effluent of heavy fraction of product ( heavy fraction of product) of the sudden cooling tower is budgeted and used to provide heat to the other streams In one embodiment, the heavy fraction of product, or any or all of the various fractions into which the heavy fraction of Product, or streams of separations from the quench medium, are used directly as fluid exchange Heat exchanger for increasing the heat content and / or temperature of the oxygenate feedstock in one or more of the stages with successively higher heat contents In addition, any of the various fractions or streams produced from separations of the medium Sudden cooling can be used to increase the heat content of other streams within the overall reaction process of oxygenate conversion and product recovery The cooled quenching medium recovered from such fractions and streams may be returned to the quench tower In a preferred embodiment, particularly when the oxygenate conversion is not complete and the quench medium consists essentially of water, the product heavy fraction is divided into two fractions , a first fraction and a second fraction The relative amounts of the first fraction and the second fraction depend on the overall amount of heat that needs to be removed from the product effluent stream in the flash cooling operation, and the temperature of the quench medium introduced in the sudden cooling tower Relative amounts are set to optimize the cost of the equipment for heat recovery and energy consumption The first fraction is cooled to a desired temperature and returned to the quench tower as recycle, ie water from sudden cooling The energy required to cool the The first fraction, ie, quench water, can be reduced by using the product effluent stream from the oxygenate conversion reactor as a heat exchange fluid to heat the oxygenate feed material before the feed matepal enters the reactor. oxygenated conversion and / or before the product effluent stream enters the quench tower The second fraction of the effluent fraction of heavy The product is sent to a fractionator to separate the flash cooling medium, which consists essentially of water - a part of which can originate as the recycled portion of the water byproduct of the oxygenate conversion reaction when the oxygenate feed material it has at least one oxygen- of other compounds, such as unreacted oxygenates or certain heavier hydrocarbons from the oxygenate conversion reaction, present in the fraction. If other streams having compositions similar to or compatible with the second fraction exist within the oxygenate conversion process and the associated process of product recovery, such other streams are combined with the second first fraction and the combined stream is sent to the fractionator. Generally, it is desirable to fractionate a mixture into components as precisely as possible. In the present invention, it is preferred that the oxygenate fraction of the head and / or the fraction containing heavy compounds of the fractionator have a water composition, as it is introduced into the second fraction of the heavy product fraction in the range of about 15 to about 99.5 mole%, preferably from about 5 to about 90 mole%. An increase in the water composition of the head fraction tends to increase the condensation temperature, and more heat can be economically recovered from the head fraction of the fractionator to improve the heat integration for the entire process. From Preferably, the recovered head oxygenate fraction contains at least about 90 mol% of the oxygenate contained in the second fraction of the heavy fraction. More preferably, the recovered head oxygenate fraction contains at least about 99 mol% of the oxygenate contained in the second fraction of the heavy fraction. The head fraction of the fractionator is condensed in a heat exchanger, i.e. a condenser, against the oxygenate feed material in one of the steps, from one to about three, where the oxygenate feed material is given successively higher heat. It is preferred that the head fraction of the fractionator have a pressure at least about 69 kPa greater than the pressure of the oxygenate feed material in the condenser. This pressure differential also increases the condensing temperature of the head fraction, making the heat recovery of the head fraction more economical. The fraction fraction of the fractionator consists essentially of the water by-product of the oxygenate conversion reaction. Preferably, this fraction of tails is budgeted and used to heat the oxygenate feed material in one of the stages, from one to about three, where the oxygenate feed material is given a successively higher heat content before entering. to the oxygenate conversion reactor. The fractionator is operated such that the The temperature of the bottoms fraction is at least about 5 ° C, preferably at least about 5 ° C, higher than the first temperature of the oxygenate feed of the storage tank. The operating temperature within the fractionator is determined by several parameters, including, but not necessarily limited to, the head pressure of the fractionator and the overall pressure drop within the fractionator. The figure of the drawings shows an embodiment of a process flow diagram according to the invention for increasing heat recovery and improving heat integration. The liquid oxygenate feed 1, such as methanol, having a first heat content, at a first temperature and a first pressure, is heated by the stream 35 in the heat exchanger 2. The stream 35 is the bottom stream of the fractionator 24, which is pressurized by pump 34. The result is a first oxygenate feed stream, heated 3 with a higher heat content than the liquid oxygenate feed stream 1. The first oxygenated, heated feed stream 3 is then heated in another heat exchanger 4 by the head fraction 26 of the fractionator 24 to form a second oxygenate feed stream, heated 5 with a heat content greater than that of stream 3. Heat exchanger 4 is a condenser or a partial condenser for fractionator 24. The second stream of oxygenated, heated feed 5 passes through the water vapor pre-heater 6 to form a heated third oxygenate feed stream 7, which is further heated by the oxygenate conversion product effluent 11 in the oxygen exchanger. heat 8 to form a fourth oxygenate feed stream, heated 9, under the effective conditions -temperature, pressure and proportion of liquid and vapor- desired for the oxygenate feed conversion. The oxygenate conversion product 11 is the effluent from the oxygenate conversion reactor 10, after being separated from the deactivated oxygenate conversion catalyst, which has carbonaceous deposits. Alternatively, the heat exchanger 8 may comprise a plurality of coils within the oxygenate conversion reactor 10. The heated, heated oxygenate feed stream 9 is fed to the oxygenate conversion reactor 10, which contains suitable catalyst to convert the oxygenate feed to olefins. The oxygenate conversion reactor 10 can take various configurations - fixed bed, fluidized bed, riser, bed in motion, or a combination thereof, with or without continuous catalyst regeneration. A fixed bed reactor is usually not favored, due to the difficulty of removing the deactivated catalyst for regeneration and returning the regenerated catalyst to the reactor. The oxygenate feed is converted into a product comprising light olefins and the catalyst becomes deactivated or partially deactivated by accumulating carbonaceous deposits, which are formed as byproducts of the oxygenate conversion reaction. The effluent resulting from the oxygenate conversion 11 flows through the heat exchanger 8. The effluent stream, produced by the oxygenated, cooled conversion 12, is sent to the quench tower 13. Alternatively, the heat exchanger 8 can be eliminated and the effluent product of the oxygenate conversion 11 is sent directly. to the quench tower 13 without intermediate cooling In the quench tower 13, the stream resulting from the oxygenate conversion 12 directly contacts a quench cooling means consisting essentially of water at an initial temperature over a series of devices of suitable contact The necessary amount of medium Sudden cooling in the quench tower 13 is dictated by several factors, including but not necessarily limited to the composition of the quench medium, the temperature of the recycle of quench medium introduced to the quench tower 13, and the desired temperature and pressure differences between the various currents These differences are discussed where appropriate The gaseous products are separated as the light product stream of product 14 The current of heavy fraction of product 15, which leaves the bottom of the quench tower at an exit temperature, comprises the bulk of the by-product of water, a portion of the unreacted oxygenate feedstock (except those oxygenates that are gaseous under the conditions of sudden cooling), a small portion of the by-products of oxygenate conversion, particularly heavy hydrocarbons (C5 +), and usually the bulk of the quench medium. A preferred quench medium is water, which for all intentions and purposes is indistinguishable from the secondary product of water. This eliminates the need for steps to separate the flash cooling medium from the secondary product of water in the heavy product fraction. In the case that a quench material other than water is used and this flash material is substantially in liquid form. under conditions of sudden cooling, the heavy fraction of product 15, or any or all of the various fractions into which the heavy product fraction is divided, can be processed to separate the quench medium from the secondary product of water. For example, if the quench medium is a high boiling hydrocarbon such as diesel fuel or similar streams, is immiscible with the by-product of water Such a sudden cooling medium can be separated by a designed landfill system appropriately in the bottom of the quench tower 13, or in an API separator or other similar devices at many different points in the process in the present invention In addition, if any heavy hydrocarbons (C5 +) are formed in the oxygenate conversion reaction , they can also be removed from the by-product of water in stream 15 or at other points in the process in substantially the same manner as or together with the removal of the quench medium. If the quench medium is a relatively light material which is substantially gaseous under the conditions of sudden cooling, and therefore is present in substantial quantities in the light fraction of product, such sudden cooling medium can be separated in processes of recovery of downstream olefms that encompass the whole process of oxygenate conversion and recovery and purification of olefmas Regardless of the above, the pressure n output of the heavy fraction stream of product 15 should be less than about 345 x 103 pascals (345 kPa) below the pressure of the liquid oxygenate feed 1 Preferentially, the outlet temperature of the stream of heavy fraction of product 15 is maintained at not less than about 25 'C below the bubble point of the secondary product of water in stream 15 A preferred pressure difference between the product heavy fraction stream 15 (lower pressure) and the supply of liquid oxygenate 1 (higher pressure) is less than 207 kPa. The product heavy fraction stream (quench stream from the quench tower) 15 can be used to provide heat to the oxygenate feed material in the heat exchangers 2, 4 and / or 6 to increase the heat content of the product. Feeding material. The oxygenate feed material contains successively higher heat contents in these steps. One or more of these steps can also be eliminated. Preferably, the quench stream of the quench tower 15 is divided into two fractions, the recycle fraction 18 and the feed fraction of the fractionator 21 The recycle fraction 18, a recycle stream of quench water, is cooled in the exchanger 19 and recycled as a quench stream 20 back to the quench tower 13. Alternatively, the recycle fraction 18 or 20 can be divided into several fractions and these fractions can be cooled to different temperatures in different heat exchangers. These fractions, or some of them, at different temperatures, can be introduced in the quench tower 13 at different points to better integrate the heat recovery and minimize the energy consumption. The heat content of fraction 18 can be used to provide heat to the oxygenate feed material in heat exchanger 2, 4 and / or 6, or in different places throughout the process Oxygen conversion and recovery and purification of olefins to provide heat and to increase heat recovery. The feed fraction of the fractionator 21, optionally mixed with other streams containing water 22, is sent to the fractionator 24. At least two streams, the head stream of the fractionator 26 and the bottom stream of the fractionator 33, are fractionated from the fraction of feed of the fractionator 21. The head stream of the fractionator 26 must contain at least about 15 mol%, preferably at least about 25 mol%, of water of the oxygenate conversion reaction. Conjunctively or alternatively to this preference of the composition, the head stream temperature of the fractionator 26 must be at least about 10 'C greater than the boiling temperature of the oxygenate feed under the conditions of the heat exchanger 4 Sufficient heat is added to the fractionator 24 via the reboiler 25, which when coupled with a sufficient number of trays in the fractionator 24 results in the production of the bottoms stream of the fractionator 33, which comprises substantially all of the byproduct of water and flash cooling medium introduced with the stream 23. Preferably, the flash cooling medium is water. When water is used as a quench medium, the stream of tails 33 consists essentially of the bulk of the water. water by-product of the oxygenate conversion reaction and additional steps are not necessary to separate the secondary product from water from the quench medium. If the quench medium is a material other than water and has not previously been separated from the secondary product. of water before introduction to the quench tower, this quench material can be separated from the secondary product of water in queue stream 33, or later in the process, as described above. -any heavy hydrocarbons (C5 +) in the oxygenated conversion process, can also be removed from the secondary product of water in stream 33, or later in the process substantially in the same way or together with the removal of the medium from Sudden cooling The queuing stream of the fractionator 33, before leaving the fractionator 24, is at a temperature that is at least about 5'C, preferably at least about 25 'C, grr than the first temperature of the oxygenated feed introduced from storage 1 to the hexchanger 2 The pressure at the top of the fractionator 24 must be at least 69 kPa grr than the pressure in the hexchanger 4 to increase the hrecovery The current 35 is used to hthe liquid oxygenate 1 supply material in the hexchanger 2 For better hrecovery, the current 36 that is output of the Hexchanger 2 preferably has a temperature equal to or less than about the temperature of stream 21. One way to further improve hintegration and increase hrecovery is to use the head stream of fractionator 26 as the source of h hfor the hexchanger 4. The cooled fractionator head stream 27 can be further fractionated in the separator 28 in the steam discharge stream 29 and the liquid reflux 30 which is returned to the fractionator 24 after the adjustment of pressure with the pump 31. It is important to maintain the head stream of the fractionator, cooled 27 to a temperature above the boiling point of the first oxygenated feed, hd 3, to provide favorable htransfer. The invention will be better understood by reference to the following example, which illustrates the invention but should not be construed as limiting the present invention. Example 1 A feed of liquid methanol 1 at a pressure of about 386.1 kPa and 38 'C absorbent hto increase its hcontent in hexchanger 2 from stream 35, to 158' C and a pressure of 1.276 kPa, of the methanol / water fractionator 24 to form the first methanol feed stream, hd 3 to a temperature of about 100 ° C and a pressure of 351.6 kPa. The first methanol feed stream, hd 3 with a hcontent of 4.722 kj / mol absorbs hfrom the head stream of the fractionator 26 in the hexchanger 4 to form the second feed stream of methanol, hd with a content of hof 6.521 kJ / mol. The stream 5 is further hd by steam in the hexchanger 6 to form the hd third methanol feed stream 7, which has an even higher hcontent than the hd third methanol feed stream. 7 (7.390 kJ / mol). The hd third methanol feed stream 7 is hd in the hexchanger 8 to form the fourth methanol feed stream, hd 9 with the effluent product of the methanol conversion 11 of the oxygenate conversion reactor 10. The fourth methanol feed stream, hd 9, having a much higher hcontent, of 17.102 kj / mol, is suitable for making contact with a catalyst in the oxygenate conversion reactor 10 to form a deactivated oxygenate conversion catalyst having carbonaceous deposits and a product 11 comprising olefins, particularly light olefins. The oxygenate conversion reactor 10 is a fluidized bed reactor with continuous catalyst regeneration and recirculation (not shown). The oxygenate conversion product 11 is separated from the deactivated oxygenate conversion catalyst having deposits carbonaceous and used to heat the stream 9 and form a stream of cooled, methanol conversion product 12. A portion of the deactivated catalyst is removed and removed for regeneration (not shown). It is preferred to remove at least about 1.0% by weight of the carbonaceous deposits of the deactivated catalyst during regeneration. It is also preferred to remove less than about 98.0% by weight of the carbonaceous deposits of the deactivated catalyst during regeneration. The regenerated catalyst is recycled back to the oxygenate conversion reactor 10 to make contact with the oxygenate feed. 99.8% becomes weight of methanol in stream 9 in the reactor 10, the balance unconverted leaving in stream 11. The product stream conversion of methanol, cooled 12 exiting the heat exchanger 8 is sent to the sudden cooling tower 13, making contact directly with a sudden cooling medium consisting essentially of water. The quench tower 13 is equipped with suitable contact devices therein. Most of the hydrocarbon products are separated as a gaseous product stream 14. The heavier products, water, and unreacted methanol, are discharged from the quench tower 13 as the quench stream of the quench tower 15 at a temperature of about 116"C and a pressure of about 262 kPa. the quench tower 15 is pressurized by the pump 16 to form the bottoms stream from the quench tower, pressurized 17, at about 689.5 kPa. About 83 mol% of the bottoms stream of the quench tower, presupzada 17, form the fraction of recycle 18 and is sent through the cooling exchanger 19 to form stream quench 20 at a lower temperature. The quench stream 20 is returned to the quench tower 13 The remainder of the quench stream of the quench tower, presupposed 17, about 17 mol%, becomes the fraction fraction feed fraction 21 fractionator 21 feed is combined with another methanol / water stream 22, a small stream recovered from other sources within the overall process of oxygenate conversion and product recovery. The combined stream 23 is sent to the fractionator 24. The head stream of the fractionator 26, containing about 89 mol% of water and about 10.5 mol% of methanol at a temperature of 152 ° C and a pressure of 551.6 kPa, is sent to the heat exchanger 4 The queues of the fractionator 24 are heated with steam in the heat exchanger 25 to produce the bottoms stream of the fractionator 33 at 158 'C and about 585 4 kPa, which mainly contains water, with only traces of other components. The stream of tails of the fractionator 33 is pressurized to about 1,274.8 kPa and the resulting stream 35 is used for the heat exchanger 2, to heat the liquid methanol feed 1. After the heat exchange, the second product stream of hot water 36 has a temperature of 46 'C at a pressure of 861.2 kPa. Table 1 shows the product selectivity and composition of the product stream 11 of the methanol conversion used to obtain the results shown in Tables 2 and 3. Feeding rates, compositions, pressures, and temperatures of various streams, as described in Example 1, are shown in Table 2. The works of the key exchangers 2, 4 and 25 are tabulated in Table 3.

Table 1 Table 2 Table 3 * As compiled using the Simulation Sciences Ine chemical process simulation program PRO / II using modified Panagiotopoulos-Reid modifications to the Soave-Redlich-Kong state equation These results show that in the oxygenate conversion process, the external heat necessary to bring the oxygenate feedstock to the desirable conditions to make contact with the catalyst, represented in the preferred embodiment by the heat exchanger 6, is reduced as a result of the increased heat recovery and the Improved Process Heat Integration Those skilled in the art will recognize that many modifications can be made to the present invention without departing from the spirit and scope of the present invention. The embodiment described herein is intended to be illustrative only and not to be taken as limitation of the invention, which is defined by the following claims

Claims (3)

1. CLAIMS 1. A process to convert an oxygenate into olefmas, with increased heat recovery and heat integration, said process comprising. heating a feed material comprising said oxygenate and contacting said feed material at a temperature of 200 to 750 ° C and a pressure of 1 kPa to 100
2. MPa, with a catalyst comprising a molecular sieve having a diameter of less than 10 Angstroms, separating said catalyst from said product, and suddenly cooling said product with a sudden cooling medium; separating said product suddenly cooled in a light fraction of product and a heavy fraction of product; and using at least a portion of said heavy product fraction to provide heat for the feed material 2. The process of any of the preceding claims, further comprising the steps of: removing a part of said catalyst after separating said product; removing at least 10% by weight of carbonaceous deposits of said catalyst to form a regenerated catalyst; and recycling said regenerated catalyst for contact with said feedstock
3. 3. The process of any of the preceding claims, wherein said feedstock is maintained at a first pressure before making contact and said heavy fraction of product has a second pressure, and wherein said second pressure is lower than said first pressure at no more than about 345 kPa The process of any of the preceding claims, wherein said oxygenate is selected from the group consisting of methanol, dimethyl ether, ethanol, methyl ethyl ether, dimethyl carbonate, methyl formate, methyl acetate, diethyl ether, and mixtures thereof The process of any of the preceding claims, wherein said catalyst is selected from the group consisting of a zeolite, a silicoalumophosphate (SAPO), a substituted silicoalummophosphate, a substituted aluminophosphate, and mixtures thereof The process of any of the preceding claims, wherein said feed material further comprises a diluent selected from the group consisting of in water, carbon dioxide, carbon monoxide, nitrogen, hydrogen, argon, helium, methane, ethane, and mixtures thereof The process of claim 5, wherein said catalyst is an SAPO selected from the group consisting of SAPO 17, SAPO-18, SAPO-34, SAPO-44, and mixtures thereof. of any of the preceding claims, wherein the flash cooling medium is water 9 The process of any of the claims above, where the product is suddenly quenched by contact with the quench medium in a quench tower without first passing through a product fractionation step. The process of any of the preceding claims, wherein the heavy product fraction is sent to a fractionator and fractionated into a fractionator head stream and a fractionator queue stream, and the fractionator head stream contains at least 15%. % molar of water. The process of claim 10, wherein the fractionator head stream contains at least 25 mol% water.