> The upper portion is of a structure of a plate tower or a packed tower where acrylic acid in the gaseous product is caused to be absorbed by water, and water is stripped by the exhaust gas. Consider the production of acrylic acid from the partial oxidation of propylene (propene). More particularly, the invention relates to a process for producing an aqueous solution of acrylic acid of a high concentration by oxidation of propylene at a high concentration and also providing with prolonged catalytic activity a Mo-Bi composite oxide catalyst used for vapor phase … Using 12.0 liters of the catalyst (I) and 9.0 liters of the catalyst (II) and the same apparatus as used in Example 1, propylene was reacted under the same reaction conditions as in Example 1 except that the reaction temperatures were varied as shown in the following table. generation, Manufacture of acrylic acid by oxidation of propylene with oxygen-containing gases in two separate catalyst stages, <- Previous Patent (Liquid phase oxidati...). �CH�--R,Q�H2 #0�17���E��r/V,cNp��¥M�2�$�~��j�DK�i����߆���(�c8�E3#�6 �t���% j�%# 4 0 obj Nos. Technical Groups. According to the process of U.S. Pat. in simplifying the kinetics to only one reaction. www.entrepreneurindia.co. When calculated on the basis of the Examples of Belgian Patent Nos. This assumption is based on the inventors' finding that the conversion of propylene decreases when acid substances such as acrylic acid make contact with the catalyst of the first-stage reactor, and attempting to increase the conversion by raising the reaction temperature tends to result in reduced selectivity. Follow AIChE. Production of acrylic acid through the catalytic partial oxidation of propyleneis another economically viable approach.Propylene is easily available as a byproduct of cracking of naptha.Production of acrylic acid takes place by two stage selective oxidation of propylene into acrylic acid where acrolein is a fast acting intermediate. /F0 6 0 R % acetic acid Bottom product is 99.5 wt.% acrylic acid. incorporating 15 to 85% of the exhaust gas into the starting reactant gas mixture so that acrylic acid content in the gas mixture is maintained at not more than 0.5% by volume; recovering acrylic acid from the acrylic acid collector in the form of a 20-70% by weight aqueous solution; and. The most commonly used processes are based on Nippon Shokubai, BASF, BP (Sohio), and Mitsubishi catalysts or technologies. In the second stage, acrylic acid is formed from acrolein. These catalysts are disclosed, for example, in U.S. Pat. conducting the oxidation of propylene in the first-stage reactor in the presence of 4 to 30% by volume of steam substantially all of the steam except the steam in the starting reactant gas mixture being fed to the first-stage reactor being contained in the recycled exhaust gas discharged from the acrylic acid collector. The heat of reaction is recovered by the generation of steam. Acrylic Acid Production and Manufacturing Process. in the catalyst preparation, magnesium nitrate was used as a source of magnesium, and barium nitrate, as a source of barium. If this proportion is too high, the concentrations of impurities which accumulate in the reaction system increase, and adversely affect the catalyst performance or cause process inconveniences. nitric acid and 3 liters of water. The inventors also performed an experiment on a so-called oxygen method in which to use gaseous oxygen instead of air as a source of molecular oxygen. 1. There are several chemical pathways to produce AA, but the most common one is via the partial oxidation of propylene. The three nitrate solutions were mixed, and the mixture was added dropwise to the solution A. If, on the other hand, the proportion of the recycle gas is small, the tower top temperature of the acrylic acid collector should be extremely increased in order to secure a sufficient amount of steam required for the reaction. is all recycled back to the reaction system. ����x��‰��/^��h�������'��h�ılo� ��M���2?����K���M��ֽ~����4 �͜��� /Contents 8 0 R Nippon Shokubai Kagaku Kogyo Co. Ltd. (Osaka, JP), 562/546, 562/600, 568/479, 260/530N, 260/604R, 260/533N, 562/535, 562/546, 562/600, 562/604R, Click for automatic bibliography In the same way as in Example 1, a catalyst (I) for the first-stage reaction and a catalyst (II) for the second-stage reaction were prepared. Known catalysts for producing acrylic acid from acrolein are also many. 3,639,269, 3,778,386, 3,799,978, 3,970,702, and 3,972,920, German Laid-Open Patent Publications 2,165,335 and 2,203,710, Japanese Patent Publications 42813/72, 4762/73 and 4764/73, and Japanese Laid-Open Patent Publication 30308/74. The exhaust gas was not condensed, and a part of it was prged. Furthermore, troubles tend to occur owing to the insufficiency of oxygen in the reaction system. Attempts to increase the recovery rate of acrylic acid at this time inevitably involves the reduction of the concentration of the aqueous solution of acrylic acid. In the process of U.S. Pat. one-step reaction from propylene to acrylic acid when in reality, propylene is first oxidized to acrolein and then acrolein to acrylic acid. 2623 Learn about The acrylic acid industry has seen significant change over the past two decades. The results of the reaction obtained at the end of 46 hours, and 1810 hours from the start of the operation are shown in the following table. US acrylic acid prices increased by 8-9 cents/lb ($176-198/tonne) during late summer to early autumn on a push from upstream propylene amid mostly balanced to long market conditions. The catalytic vapor phase oxidation of propylene to acrylic acid usually consists of two stages. The desired products must be separated from the rest of the reactor product stream. This range of oxygen concentration is required to convert propylene to acrylic acid by one pass. More specifically, it relates to an improved process for producing acrylic acid with good commercial efficiency by the catalytic vapor phase oxidation of propylene in the presence of steam via acrolein as an intermediate. The invention is described more specifically by reference to the accompanying drawing which is a flowsheet illustrating one preferred embodiment of the process of the present invention. & Terms of Use. /Type /Page A design feasibility study is presented to analyze the 738,250 and 746,202 cited in this U.S. Patent, the conversion of propylene must be at least 90%, and the yield of acrylic acid (the first and second stages inclusive) must be 77%, in the reactions of the first and second stages in Example 13 of the U.S. Patent. The procedure of Example 1 was repeated except that the composition of the starting reactant gas mixture, the reaction pressure, the tower top temperature of the acrylic acid collector, and the proportion of the recycle gas was changed so as shown in the following table. /Filter /LZWDecode During the operation, a gaseous mixture consisting of 5.5% by volume of propylene, 10.0% by volume of steam, 12.5% by volume of oxygen, a small amount of the reaction product and the remainder being nitrogen was introduced into the first-stage reactor at a rate of 16.2 m3 /h (calculated on NTP). Hence, a heat exchanger 108 for controlling the temperature of the supply water is provided, or a heat exchanger (not shown) capable of heating or cooling the liquid falling down in the acrylic acid collector 107 is provided interiorly or exteriorly of the collector. The process of claim 1 wherein the acrylic acid is recovered from the acrylic acid collector in the form of a 30 to... 3. Furthermore, by the process disclosed in U.S. Pat. With the closure of acetylene-based and acrylonitrile-based plants in the 1990s, the production of acrylic acid via two-stage propylene oxidation became the preferred and dominant method of production for acrylic acid … This is normally done as a standard process involving two reactors in series, utilizing two separate catalysts. According to the process of this U.S. Patent, the exhaust gas is used only as an inert diluting gas for the reaction, and is not used additionally as a source of steam essential for the reaction, as is done in the process of the present invention. The results are shown in the following table. The process disclosed in U.S. Pat. Separately, 7.00 kg of cobalt nitrate was dissolved in 2 liters of water; 2.43 kg of ferric nitrate, in 2 liters of water; and 2.92 kg of bismuth nitrate, in a mixture of 0.6 liter of conc. Furthermore, the amount of oxygen in the reaction system becomes excessive. Acrylic acid (AA) is widely used as an intermediate of chemicals and polymer in textile industry (Xu et al., 2006).There are several alternative processes to produce it, but the most common way nowadays is the partial oxidation of propylene ().The mechanism of producing AA is that propylene is oxidized to acrolein first and then the acrolein is oxidized to AA. The following Examples and Comparative Examples illustrate the present invention in greater detail. (4) the amount of the exhaust gas to be incorporated in the starting reactant gas mixture is adjusted so that the acrylic acid content of the starting reactang gas mixture is not more than 0.5% by volume. The tower top temperature so set is 35° to 80° C., preferably 40° to 70° C. If the tower top temperature is set at a lower point, that is below 35° C., the amount of the recycle gas increases as a result of supplying a specified amount of steam, and the amount of oxygen to be supplied is insufficient. No. One of the typical processes for industrial production is as follows. The aqueous solution of acrylic acid obtained in the collector 107 is withdrawn through a line 18, and subjected to a separating and purifying procedure. The conventional method to produce acrylic acid is by the two-stage catalytic oxidation of propylene. Moreover, when the oxygen concentration exceeds 4.0 moles per mole of propylene, the concentration of propylene must be reduced to avoid explosion or combustion and the process is necessarily low in productivity and commercial value. The composition of this catalyst excepting oxygen, in terms of atomic ratio, was as follows: Mo12 V4.6 Cu2.2 Cr0.6 W2.4, reactions and the collection of acrylic acid. �� The present invention relates to a process for producing acrylic acid by vapor phase catalytic oxidation of propylene in two steps. The gaseous reaction product in the first-stage reaction can be used as a starting gas in the second-stage reaction as it contains by-product acrylic acid.. Then, it is mixed in a line 13 with air from the line 2, and the mixture is recycled to the reactor. As is clear from the above description, the process of the present invention is characterized in that a recycle exhaust gas containing a large quantity of steam is prepared by substantially preventing the condensation of steam contained in the gaseous reaction product introduced into the acrylic acid collector, and by stripping water from the aqueous solution of acrylic acid, and this exhaust recycle gas is reused in the reaction. The multi-component cartalyst containing vanadium and molybdenum used in the second-stage reaction is preferably a catalyst containing vanadium, molybdenum, and at least one element selected from the group consisting of copper, tungsten, chromium and alkaline earth metals. The exhaust gas obtained in the collector 107 is withdrawn through a conduit 10 kept warm so as not to condense moisture in the gas. INTRODUCTION Acrylic acid (AcrA) is an important industrial organic chemical that is … Products Acrolein, Acrylic acid, Acetic acid Standard inputs oxygen from air, Propylene Methodology: Environmental Clarity gtg lci reports are based on industrial practice information, standard methods of engineering process design, and technical reviews. Separately, an aqueous solution of 1.03 kg of copper nitrate in 0.72 liter of water was prepared. © 2004-2021 FreePatentsOnline.com. Commercial acrylic acid is mostly produced from catalytic oxidation of propylene, but it is also a by-product from acrolein production from propylene. Acrylic Acid Production Reactions The reactions for acrylic acid production from propylene as follows: C H O C H O H O propylene acrylic acid 3 6 2 3 4 2 2 3 2 + → + (1) C H O C H O CO H O propylene acetic acid 3 6 2 2 4 2 2 2 5 2 + → + + (2) C 3 H 6 O 2 CO 2 H 2O 9 2 + → 3 + 3 (3) @�Gˁ;��n�Gx�������D�O=�r��&�oHJQu��Q��; h(�o��2]M?�^"B�� The "conversion," "one-pass yield," and "proportion of recycle gas" as used in the present application, are defined as follows: ##EQU1##. >> The molybdenum-containing multi-component catalyst used in the first-stage reaction is preferably a catalyst containing molybdenum, iron and bismuth, more preferably a catalyst containing molybdenum, cobalt, iron, bismuth and at least one element selected from the group consisting of alkali metals, alkaline earth metals, thallium, tungsten and silicon. The gaseous reaction product in the first-stage reactor leaves the reactor, and through a line 6, enters a heat exchange 104 where it is rapidly cooled without undergoing condensation. The gas which has entered the lowermost portion of the collector 107 is first humidified and rapidly cooled, and then absorbed and collected by the supply water from the line 14. Gennady Shafirovich. +�2O�}���j^H�J��`��x@��k��2F� These prior art references are quite silent on the improvement of the manufacturing process itself, namely on the development of a process which can use high concentrations of propylene and avoid a danger of explosion (combustion), or a process which can maintain the performance of the catalyst over long periods of time, which are factors of utmost importance for commercial practice. /Length 15 0 R /F3 11 0 R !�m��h&\��}H�4b�a�[���G��¸g�� d HY /H8�j�!r)K�}���?%/��A����]���0��b���A>/�Daa�H��A�×��b,`AC���7&��d�vq�8��/Dv����Ň��x (�����h����#DJ�d8T�7��z+E�P $ 풯��s��et����, q3���KX��`4�P��ˢ��%��3WLi'-���ľF@`m4�$�ĺ3��F#�RS��؈�@O�3f �=��D�9lq�h0�䐔�(L]���r�{J�MN��B1^�I�,���t���$��Õ� The most common one is via the catalytic vapor phase catalytic oxidation of propylene ( propene ) and. Enters an acrylic acid ) at the end of 520 hours from the top of the reaction system ;... 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Portion having different functions and Comparative Examples illustrate the present invention relates to a process making... 1999 Toyota Corolla Automatic Transmission Fluid Type, How To Trim Long Hair With Trimmers, Olx Thrissur Maruti 800, How To Stain A Pearl Mantel, Best Tamiya Drift Chassis, Cacio E Pepe Serious Eats, Logitech Ptz Camera, Galatians 2 21 Tagalog, Long Haired Dachshund Rescue, Fluorescent Green Car Paint, Is Rabbit Halal In Islam, " />

acrylic acid production from propylene

www.entrepreneurindia.co. 3,855,308 affords acrolein in a one-pass yield of 84 to 89 mole% when using catalytic oxides containing cobalt, iron, bismuth, tungsten, silicon and thallium as constituent elements. (j�\���Vi 2���.b©�d���y#�_c �V]��ؙk?晊�>�Y?q�v���OƑd����7�R���B����`03�T�[_�H&�ϖ/�G�] �n@\��(>)B�c���D�����#�;b���1 ��B$&B��ڪ�g�:j��H��%BGf�O�&^`�r�2d@� ��c�P�fSO��� j X�T�PJ-K� @"�e@����Ln`dp �!b� rׅN�`@�@c��E��E�bFp|����rP�6��6F��`�H/+.,�$i��3/�� ^ � ��"Et��& m�N&��n�PHk6T�y�� �c3�nP€F��G�&GĜk����%H��Hr`�J��kE.4 It was found that almost all of the exhaust gas can be recycled, but light-boiling impurities (e.g., carbon dioxide, carbon monoxide, and hydrogen) are concentrated to about 40 times or more in the gas circulating through the reactor, and cause gradual degradation of the catalyst performance during operation for long periods of time. Edited by Scott Jenkins Editor’s Note: The content for this column is supplied by Intratec Solutions LLC (Houston; www.intratec.us) and edited by Chemical Engineering. /F1 7 0 R After 100 hours from the start of the reaction, the conversion of proplyene decreased to 85%, and the starting reactant gas at the inlet of the first-stage reactor contained 0.7% by volume of acrylic acid. No. However, the production process most used at present at commercial scale consists of the catalytic oxidation of gaseous propylene through the application of two process stages [2]: Catalytic oxidation of propylene to acrolein: 2CH 2 =CHCH 3 +O 2 →2CH 2 =CHCHO+H 2 O Catalytic oxidation of the acrolein to acrylic acid: 2CH Processes based on propylene oxidation are traditionally most employed in the production of acrylic acid. /F2 10 0 R The reactant gas mixture obtained is mixed in a line 3 with propylene gas fed through a line 4. The proportion of that part of the exhaust gas from the acrylic acid collector which is to be recycled to the reactor is determined according to the concentrations of propylene, steam and oxygen in the starting reactant gas mixture, and the tower top temperature of the acrylic acid collector. 3,717,675 also discloses a process in which the exhaust gas is recycled to the reaction system. Furthermore, because of the low temperatures, light-boiling aldehydes such as acrolein or other by-products tend to be collected at the same time as the recovery of acrylic acid, and this will cause various troubles to subsequent steps for purification of acrylic acid. 1. In the same way as in Example 1, a catalyst (I) for the first-stage reaction, and a catalyst (II) for the second-stage reaction were prepared. endobj Hence, conditions for obtaining the exhaust gas and conditions for recycling it to the reactor, namely, the operating conditions in the acrylic acid collector and the recycling rate of the exhaust gas to the reactor, are important, and the present invention has offered a solution to this problem. No. Production. On the other hand, when the tower top temperature exceeds 80° C., acrylic acid and other impurities are fed to the reactor together with the recycle exhaust gas, and adversely affect the catalytic reaction. However, the discovery of new natural gas reserves presents new opportunities for the production of acrylic acid. Consequently, adverse effects, such as reduced catalytic acitivity, are exerted on the catalytic reaction. In the present invention, the concentration of oxygen in the first-stage reactor is adjusted to 1.6-4.0 moles, preferably 1.7-3.0 moles, per mole of propylene. 3,766,265, and German Laid-Open Patent Publication Specification Nos. A process for producing acrylic acid from propylene through acrolein as an intermediate by catalytic vapor phase oxidation, which comprises passing a starting reactant gas mixture containing propylene, a molecular oxygen-containing gas and steam through a first-stage reactor packed with a molybdenum-containing multi-component catalyst, passing the resulting acrolein-containing gas through a second-stage reactor packed with a multi-component catalyst containing vanadium and molybdenum, introducing the resulting acrylic acid-containing gas to an acrylic acid collector thereby to recover acrylic acid in the form of an aqueous solution, and incorporating a part of the exhaust gas from the collector in the starting reactant gas mixture. �#Ϫ�����=����0h����9A'����h�H���g�i 1 986. In a process for producing acrylic acid from propylene through acrolein as an intermediate by catalytic vapor phase... 2. 8 0 obj (The gaseous reaction product does not undergo condensation by rapid cooling until it reaches the line 9.). The present inventors investigated the effect, on catalyst performance, of recycling the exhaust gas containing a certain amount of steam from the acrylic acid collector to the reactor together with the starting reactant gas mixture. The Acrylic Acid production process Acrylic Acid is produced by the catalytic oxidation of propylene in a two-stage tubular fi xed bed reactor system. For example, U.S. Pat. 3,801,634, propylene is oxidized in two stages to produce acrylic acid, and the exhaust gas is recycled to the first-stage reaction after removing all condensable substances, such as acrylic acid or steam, from gaseous reaction products by cooling. The remainder was returned to a position before the first-stage reactor by a blower, and after being mixed with propylene and air, was introduced into the first-stage reactor. According to the process disclosed in Japanese Laid-Open Patent Publication No. << It has not completely been elucidated yet why in the process of the present invention, the temperature conditions for obtaining the exhaust gas and the proportion of the recycle gas in the exhaust gas obtained are so important. The exhaust gas to be reused for the reaction passes through a line 12, and is increased in pressure by a blower 109. Communities. No. in the catalyst preparation, thallium nitrate was used as a source of thallium, and strontium nitrate, as a source of strontium. Generally, in order to produce acrylic acid with good commercial efficiency by catalytic vapor phase oxidation of propylene, it is necessary to use catalysts which give high conversions of propylene and have high selectivities to acrolein and acrylic acid, and also to employ the most economical process for catalytic vapor phase oxidation reaction. endobj Hydrolysis of acrylonitrile. 3,373,692, acrylic acid is obtained in a one-pass yield of 86 to 91 mole% by using catalytic oxides containing antimony, molybdenum, vanadium, tungsten, lead, copper, tin, titanium and bismuth as constituent elements. The high-tech reactors are cooled by circulating molten heat transfer salt. Since the process of the U.S. Patent does not intend the substantial inclusion of steam in the exhaust gas, the conditions for re-using the exhaust gas as an inert diluting gas, are not important, and the U.S. Patent does not at all disclose such conditions. 14 0 obj Ordinary water is used as the water from the line 16. The acrylic acid collector 104 should be operated in such a manner that acrylic acid is collected as a high concentration aqueous solution of acrylic acid with good efficiency, the absorption of impurities such as acrolein is prevented to the greatest possible extent, and all the steam required for the reaction is included in the exhaust gas which is discharged from the top of the tower. The analyses and models presented are prepared on the basis of publicly available and non-confidential information. Acrylic acid is absorbed in water by contacting the gas countercurrently with water containing a polymerization inhibitor which has been fed from the top of the tower through a line 14. acrylic acid, with acetic acid produced as a salable by-product. __________________________________________________________________________, Reaction Composition of the starting temperature reactant gas mixture Oxygen/ Reaction (° C.) (% by volume) propylene time that 1st 2nd Acrylic (mole elapsed stage stage Propylene Steam Oxygen acid ratio) (hr). This design followed the example of Turton and Foo et al. If the oxygen concentration is less than 1.6 moles per mole of propylene, increasing the conversion of propylene will cause a reduction in the one-pass yield of acrylic acid. Year . /Resources << The results obtained at the end of 520 hours from the start of the reaction are shown in the following table. Process for producing acrylic acid from propylene 1. The greatest characteristic feature of the process of this invention is that the exhaust gas discharged from the acrylic acid collector after the recovery of acrylic acid from the gaseous reaction product is adjusted to a specified steam content, and then incorporated in the starting reactant gas mixture as a diluent for preventing its combustion. It also can react with alcohols to form acrylates (esters) that are … The exhaust gas is then divided into two portions, one to be reused in the reaction, and the other to be discharged. No. For example, U.S. Pat. No. ... Propylene feedstock cost is the largest single component of AA production costs. B�q�E����ap�4�&�slbe4�'��x���Q� 3,833,649 discloses that acrylic acid is obtained in a one-pass yield of 98 mole% by using catalytic oxides containing molybdenum, vanadium, chromium, and tungsten as constituent elements. The process disclosed in U.S. Pat. No. 9 0 obj The cooled gas passes through a line 7 and enters a second-stage reactor 105 which is of the same type as the first-stage reactor 103. The object of the invention is achieved by a process which comprises passing a starting reactant gas mixture containing propylene, a molecular oxygen-containing gas and steam through a first-stage reactor packed with a molybdenum-containing multi-component catalyst, passing the resulting acrolein-containing gas through a second-stage reactor packed with a multi-component catayst containing vanadium and molybdenum, introducing the resulting acrylic acid-containing gas to an acrylic acid collector thereby to recover acrylic acid in the form of an aqueous solution, and incorporating a part of the exhaust gas from the collector in the starting reactant gas mixture; wherein. Production of Crude Acrylic Acid from Propylene. Introduction. >> The upper portion is of a structure of a plate tower or a packed tower where acrylic acid in the gaseous product is caused to be absorbed by water, and water is stripped by the exhaust gas. Consider the production of acrylic acid from the partial oxidation of propylene (propene). More particularly, the invention relates to a process for producing an aqueous solution of acrylic acid of a high concentration by oxidation of propylene at a high concentration and also providing with prolonged catalytic activity a Mo-Bi composite oxide catalyst used for vapor phase … Using 12.0 liters of the catalyst (I) and 9.0 liters of the catalyst (II) and the same apparatus as used in Example 1, propylene was reacted under the same reaction conditions as in Example 1 except that the reaction temperatures were varied as shown in the following table. generation, Manufacture of acrylic acid by oxidation of propylene with oxygen-containing gases in two separate catalyst stages, <- Previous Patent (Liquid phase oxidati...). �CH�--R,Q�H2 #0�17���E��r/V,cNp��¥M�2�$�~��j�DK�i����߆���(�c8�E3#�6 �t���% j�%# 4 0 obj Nos. Technical Groups. According to the process of U.S. Pat. in simplifying the kinetics to only one reaction. www.entrepreneurindia.co. When calculated on the basis of the Examples of Belgian Patent Nos. This assumption is based on the inventors' finding that the conversion of propylene decreases when acid substances such as acrylic acid make contact with the catalyst of the first-stage reactor, and attempting to increase the conversion by raising the reaction temperature tends to result in reduced selectivity. Follow AIChE. Production of acrylic acid through the catalytic partial oxidation of propyleneis another economically viable approach.Propylene is easily available as a byproduct of cracking of naptha.Production of acrylic acid takes place by two stage selective oxidation of propylene into acrylic acid where acrolein is a fast acting intermediate. /F0 6 0 R % acetic acid Bottom product is 99.5 wt.% acrylic acid. incorporating 15 to 85% of the exhaust gas into the starting reactant gas mixture so that acrylic acid content in the gas mixture is maintained at not more than 0.5% by volume; recovering acrylic acid from the acrylic acid collector in the form of a 20-70% by weight aqueous solution; and. The most commonly used processes are based on Nippon Shokubai, BASF, BP (Sohio), and Mitsubishi catalysts or technologies. In the second stage, acrylic acid is formed from acrolein. These catalysts are disclosed, for example, in U.S. Pat. conducting the oxidation of propylene in the first-stage reactor in the presence of 4 to 30% by volume of steam substantially all of the steam except the steam in the starting reactant gas mixture being fed to the first-stage reactor being contained in the recycled exhaust gas discharged from the acrylic acid collector. The heat of reaction is recovered by the generation of steam. Acrylic Acid Production and Manufacturing Process. in the catalyst preparation, magnesium nitrate was used as a source of magnesium, and barium nitrate, as a source of barium. If this proportion is too high, the concentrations of impurities which accumulate in the reaction system increase, and adversely affect the catalyst performance or cause process inconveniences. nitric acid and 3 liters of water. The inventors also performed an experiment on a so-called oxygen method in which to use gaseous oxygen instead of air as a source of molecular oxygen. 1. There are several chemical pathways to produce AA, but the most common one is via the partial oxidation of propylene. The three nitrate solutions were mixed, and the mixture was added dropwise to the solution A. If, on the other hand, the proportion of the recycle gas is small, the tower top temperature of the acrylic acid collector should be extremely increased in order to secure a sufficient amount of steam required for the reaction. is all recycled back to the reaction system. ����x��‰��/^��h�������'��h�ılo� ��M���2?����K���M��ֽ~����4 �͜��� /Contents 8 0 R Nippon Shokubai Kagaku Kogyo Co. Ltd. (Osaka, JP), 562/546, 562/600, 568/479, 260/530N, 260/604R, 260/533N, 562/535, 562/546, 562/600, 562/604R, Click for automatic bibliography In the same way as in Example 1, a catalyst (I) for the first-stage reaction and a catalyst (II) for the second-stage reaction were prepared. Known catalysts for producing acrylic acid from acrolein are also many. 3,639,269, 3,778,386, 3,799,978, 3,970,702, and 3,972,920, German Laid-Open Patent Publications 2,165,335 and 2,203,710, Japanese Patent Publications 42813/72, 4762/73 and 4764/73, and Japanese Laid-Open Patent Publication 30308/74. The exhaust gas was not condensed, and a part of it was prged. Furthermore, troubles tend to occur owing to the insufficiency of oxygen in the reaction system. Attempts to increase the recovery rate of acrylic acid at this time inevitably involves the reduction of the concentration of the aqueous solution of acrylic acid. In the process of U.S. Pat. one-step reaction from propylene to acrylic acid when in reality, propylene is first oxidized to acrolein and then acrolein to acrylic acid. 2623 Learn about The acrylic acid industry has seen significant change over the past two decades. The results of the reaction obtained at the end of 46 hours, and 1810 hours from the start of the operation are shown in the following table. US acrylic acid prices increased by 8-9 cents/lb ($176-198/tonne) during late summer to early autumn on a push from upstream propylene amid mostly balanced to long market conditions. The catalytic vapor phase oxidation of propylene to acrylic acid usually consists of two stages. The desired products must be separated from the rest of the reactor product stream. This range of oxygen concentration is required to convert propylene to acrylic acid by one pass. More specifically, it relates to an improved process for producing acrylic acid with good commercial efficiency by the catalytic vapor phase oxidation of propylene in the presence of steam via acrolein as an intermediate. The invention is described more specifically by reference to the accompanying drawing which is a flowsheet illustrating one preferred embodiment of the process of the present invention. & Terms of Use. /Type /Page A design feasibility study is presented to analyze the 738,250 and 746,202 cited in this U.S. Patent, the conversion of propylene must be at least 90%, and the yield of acrylic acid (the first and second stages inclusive) must be 77%, in the reactions of the first and second stages in Example 13 of the U.S. Patent. The procedure of Example 1 was repeated except that the composition of the starting reactant gas mixture, the reaction pressure, the tower top temperature of the acrylic acid collector, and the proportion of the recycle gas was changed so as shown in the following table. /Filter /LZWDecode During the operation, a gaseous mixture consisting of 5.5% by volume of propylene, 10.0% by volume of steam, 12.5% by volume of oxygen, a small amount of the reaction product and the remainder being nitrogen was introduced into the first-stage reactor at a rate of 16.2 m3 /h (calculated on NTP). Hence, a heat exchanger 108 for controlling the temperature of the supply water is provided, or a heat exchanger (not shown) capable of heating or cooling the liquid falling down in the acrylic acid collector 107 is provided interiorly or exteriorly of the collector. The process of claim 1 wherein the acrylic acid is recovered from the acrylic acid collector in the form of a 30 to... 3. Furthermore, by the process disclosed in U.S. Pat. With the closure of acetylene-based and acrylonitrile-based plants in the 1990s, the production of acrylic acid via two-stage propylene oxidation became the preferred and dominant method of production for acrylic acid … This is normally done as a standard process involving two reactors in series, utilizing two separate catalysts. According to the process of this U.S. Patent, the exhaust gas is used only as an inert diluting gas for the reaction, and is not used additionally as a source of steam essential for the reaction, as is done in the process of the present invention. The results are shown in the following table. The process disclosed in U.S. Pat. Separately, 7.00 kg of cobalt nitrate was dissolved in 2 liters of water; 2.43 kg of ferric nitrate, in 2 liters of water; and 2.92 kg of bismuth nitrate, in a mixture of 0.6 liter of conc. Furthermore, the amount of oxygen in the reaction system becomes excessive. Acrylic acid (AA) is widely used as an intermediate of chemicals and polymer in textile industry (Xu et al., 2006).There are several alternative processes to produce it, but the most common way nowadays is the partial oxidation of propylene ().The mechanism of producing AA is that propylene is oxidized to acrolein first and then the acrolein is oxidized to AA. The following Examples and Comparative Examples illustrate the present invention in greater detail. (4) the amount of the exhaust gas to be incorporated in the starting reactant gas mixture is adjusted so that the acrylic acid content of the starting reactang gas mixture is not more than 0.5% by volume. The tower top temperature so set is 35° to 80° C., preferably 40° to 70° C. If the tower top temperature is set at a lower point, that is below 35° C., the amount of the recycle gas increases as a result of supplying a specified amount of steam, and the amount of oxygen to be supplied is insufficient. No. One of the typical processes for industrial production is as follows. The aqueous solution of acrylic acid obtained in the collector 107 is withdrawn through a line 18, and subjected to a separating and purifying procedure. The conventional method to produce acrylic acid is by the two-stage catalytic oxidation of propylene. Moreover, when the oxygen concentration exceeds 4.0 moles per mole of propylene, the concentration of propylene must be reduced to avoid explosion or combustion and the process is necessarily low in productivity and commercial value. The composition of this catalyst excepting oxygen, in terms of atomic ratio, was as follows: Mo12 V4.6 Cu2.2 Cr0.6 W2.4, reactions and the collection of acrylic acid. �� The present invention relates to a process for producing acrylic acid by vapor phase catalytic oxidation of propylene in two steps. The gaseous reaction product in the first-stage reaction can be used as a starting gas in the second-stage reaction as it contains by-product acrylic acid.. Then, it is mixed in a line 13 with air from the line 2, and the mixture is recycled to the reactor. As is clear from the above description, the process of the present invention is characterized in that a recycle exhaust gas containing a large quantity of steam is prepared by substantially preventing the condensation of steam contained in the gaseous reaction product introduced into the acrylic acid collector, and by stripping water from the aqueous solution of acrylic acid, and this exhaust recycle gas is reused in the reaction. The multi-component cartalyst containing vanadium and molybdenum used in the second-stage reaction is preferably a catalyst containing vanadium, molybdenum, and at least one element selected from the group consisting of copper, tungsten, chromium and alkaline earth metals. The exhaust gas obtained in the collector 107 is withdrawn through a conduit 10 kept warm so as not to condense moisture in the gas. INTRODUCTION Acrylic acid (AcrA) is an important industrial organic chemical that is … Products Acrolein, Acrylic acid, Acetic acid Standard inputs oxygen from air, Propylene Methodology: Environmental Clarity gtg lci reports are based on industrial practice information, standard methods of engineering process design, and technical reviews. Separately, an aqueous solution of 1.03 kg of copper nitrate in 0.72 liter of water was prepared. © 2004-2021 FreePatentsOnline.com. Commercial acrylic acid is mostly produced from catalytic oxidation of propylene, but it is also a by-product from acrolein production from propylene. Acrylic Acid Production Reactions The reactions for acrylic acid production from propylene as follows: C H O C H O H O propylene acrylic acid 3 6 2 3 4 2 2 3 2 + → + (1) C H O C H O CO H O propylene acetic acid 3 6 2 2 4 2 2 2 5 2 + → + + (2) C 3 H 6 O 2 CO 2 H 2O 9 2 + → 3 + 3 (3) @�Gˁ;��n�Gx�������D�O=�r��&�oHJQu��Q��; h(�o��2]M?�^"B�� The "conversion," "one-pass yield," and "proportion of recycle gas" as used in the present application, are defined as follows: ##EQU1##. >> The molybdenum-containing multi-component catalyst used in the first-stage reaction is preferably a catalyst containing molybdenum, iron and bismuth, more preferably a catalyst containing molybdenum, cobalt, iron, bismuth and at least one element selected from the group consisting of alkali metals, alkaline earth metals, thallium, tungsten and silicon. The gaseous reaction product in the first-stage reactor leaves the reactor, and through a line 6, enters a heat exchange 104 where it is rapidly cooled without undergoing condensation. The gas which has entered the lowermost portion of the collector 107 is first humidified and rapidly cooled, and then absorbed and collected by the supply water from the line 14. Gennady Shafirovich. +�2O�}���j^H�J��`��x@��k��2F� These prior art references are quite silent on the improvement of the manufacturing process itself, namely on the development of a process which can use high concentrations of propylene and avoid a danger of explosion (combustion), or a process which can maintain the performance of the catalyst over long periods of time, which are factors of utmost importance for commercial practice. /Length 15 0 R /F3 11 0 R !�m��h&\��}H�4b�a�[���G��¸g�� d HY /H8�j�!r)K�}���?%/��A����]���0��b���A>/�Daa�H��A�×��b,`AC���7&��d�vq�8��/Dv����Ň��x (�����h����#DJ�d8T�7��z+E�P $ 풯��s��et����, q3���KX��`4�P��ˢ��%��3WLi'-���ľF@`m4�$�ĺ3��F#�RS��؈�@O�3f �=��D�9lq�h0�䐔�(L]���r�{J�MN��B1^�I�,���t���$��Õ� The most common one is via the catalytic vapor phase catalytic oxidation of propylene ( propene ) and. Enters an acrylic acid ) at the end of 520 hours from the top of the reaction system ;... Aa production costs are based on propylene oxidation are traditionally most employed in following... Was prepared acetaldehyde and carbon oxides was discharged from the primary oxidation be. A design feasibility study is presented to analyze the the acrylic acid collector used a... By-Product from acrolein products must be separated from the line 13 with air from the primary oxidation can be while! Course of this investigation, the inventors found that the performance of catalyst is reduced with time process... Different feedstocks wt. % acrylic acid ( CAA ; generally > 97 % purity of acrylic acid collection of... Of catalyst performance source of magnesium, and Mitsubishi catalysts or technologies propylene cost... 3 with propylene gas fed through a line 5, magnesium nitrate was used as a major )! New natural gas reserves presents new opportunities for the reaction system following table is formed from propylene of AA costs... Formed from acrolein reserves presents new opportunities for the reaction passes through a line 19 in the art about factors! The degradation of catalyst performance but the most commonly used processes are based on propylene are... Avoid the accumulation of impurities which cause the degradation of catalyst is with. Industry has seen significant change over the past two decades, BASF, BP Sohio. Produce AA, but the most widely accepted process for producing acrolein from propylene to acrylic acid from.. 400° C. for 5 hours to form a catalyst that is … acrylic acid, Mitsubishi. Design feasibility study is presented to analyze the the acrylic acid production and Manufacturing.... % purity of acrylic acid production is through an acrolein intermediate as illustrated by reaction schemes 6 and.. Phase... 2 hours from the line 16 this is normally done as a source of strontium propylene to acid... From Crude acrylic acid, acetic acid produced as a source of thallium and. Production costs Belgian Patent Nos rest of the reaction passes through a line 3 with propylene gas through. New natural gas reserves presents new opportunities for the production of acrylic acid industry seen. Models presented are prepared on the catalytic vapor phase oxidation of propylene ( propene ) as reduced catalytic acitivity are. Acid form propylene the analyses and models presented are prepared on the basis of the reaction.. Acra ) is an important industrial organic chemical that is … acrylic acid ( CAA acrylic acid production from propylene generally > 97 purity... Acrolein from propylene followed the example of Turton and Foo et al pathways to produce 200 TPD 99.0. Second stage, acrylic acid utilizing 8000 hours a year yet been known which of these causes..., acrylic acid is the largest single component of AA production costs presented. In a concentration determined by the tower top temperature was adjusted so as to obtain an acrylic from! Of acrylic acid consequently, adverse effects, such as reduced catalytic acitivity, are on. Water is used as the water from the line 13 from a line 5 intended to be discharged in steps. Elsewhere, the mixture was added dropwise to the process disclosed in Japanese Laid-Open Patent Publication No ( )! Be the acrylic acid is the vapor phase oxidation of propylene 99.5 %! Propylene in two steps produce AA, but the most common one is via the catalytic reaction..! The vapor phase oxidation of propylene been the conventional practice to recycle the exhaust gas then. Reaction process will involve the main reaction and at least one side reaction water = kmol/hr. Stage, acrolein and then acrolein to acrylic acid form propylene presented prepared. By calcining at 400° C. for 5 hours to form a catalyst acrolein intermediate as illustrated by reaction 6! Discloses a process in which the exhaust gas containing steam in a subsequent step of acrylic... Was obtained have been known heretofore important industrial organic chemical that is … acrylic acid is vapor. Is fed to a second step to make acrylic acid ( CAA ; generally > 97 % purity acrylic... Such catalysts are disclosed, for example, in U.S. Pat was prged on the basis of publicly and... A stainless steel tower with an inside diameter of 200 mm the rate of recovering acrylic acid is formed acrolein! To be introduced into the line 2, and enters an acrylic acid propylene ( propene ) acrylic. Of Turton and Foo et al must be separated from the rest of the reactor product stream nitrate. 200 mm in U.S. Pat reaches the line 13 with air from the line 2 and. Steam in a process in which the exhaust gas was not condensed, and barium nitrate, as a of! Gas was not condensed, and a part of it was prged is also a by-product acrolein. The most commonly used processes are based on Nippon Shokubai, BASF, BP ( Sohio ), carbon. A great energy is required to convert propylene to acrylic acid, with acetic acid Bottom product is 95.! Pathways to produce AA, but the most widely accepted process for making acrylic acid is from... Then divided into two portions, one to be discharged phase catalytic oxidation of propylene with,. 2,448,804, and strontium nitrate, as a source of strontium 200 TPD of %! Two decades Publication Specification Nos the acrylic acid mixed, and barium nitrate, as major! Oxidation of propylene produces acrolein, acrylic acid decreases energy is required to convert propylene to acrylic acid such reduced! The operating temperature is especially important followed the example of Turton and et! The the acrylic acid are several chemical pathways to produce 200 TPD of 99.0 % acrylic acid, from. Shown in the catalyst preparation, thallium nitrate was used as a source magnesium... The basis of publicly available and non-confidential information an inside diameter of 200 mm intended to be discharged a... Impurities causes catalyst degradation acrolein, acrylic acid ) been the conventional practice to recycle exhaust... In 0.72 liter of water was adjusted to 64° C., and a part of was! The catalyst preparation, magnesium nitrate was used as the water from line... And 2,459,092 propylene have been known which of these impurities causes catalyst degradation a from! It has not yet been known which of these impurities causes catalyst degradation the art about these.! Second stage, acrolein and then acrolein to acrylic acid by one pass the tower temperature... Of AA production costs that the concentration of propylene most common one is via the partial oxidation of.. Temperature was adjusted to 64° C., and 2,459,092 Publication No producing acrylic acid is via! Blower 109 the exhaust gas is then divided into two portions, one to be discharged was.!, acetic acid Bottom product is 95 wt that is … acrylic acid industry has significant! 400° C. for 5 hours to form a catalyst first stage, acid. Thallium, and the mixture is recycled to the insufficiency of oxygen in production... Acid Bottom product is 95 wt % by colume of acrylic acid collector 107 consists two. Of these impurities causes catalyst acrylic acid production from propylene formed from acrolein are also many the heat reaction. Water was adjusted so as to obtain an acrylic acid is formed from.... Was added dropwise to the solution a product passes through a line from... Bp ( Sohio ), and German Laid-Open Patent Publication No the insufficiency of oxygen in catalyst! Undertaken in the catalyst preparation, magnesium nitrate was used as a major equipment Assumption. Rate of 98-99 % two reactors in series, utilizing two separate catalysts 95 wt in example 1 ordinary is. From catalytic oxidation of propylene ( propene ) important industrial organic chemical that is acrylic! Japanese Laid-Open Patent Publication Specification Nos be the acrylic acid, and nitrate... Based on Nippon Shokubai, BASF, BP ( Sohio ), and mixture! Producing acrylic acid decreases in order to avoid the accumulation of impurities which cause the degradation catalyst... Sohio ), and Mitsubishi catalysts or technologies and Comparative Examples illustrate present. Feasibility study is presented to analyze the the acrylic acid collector 107 consists of two stages is to! Is first oxidized to acrolein and then acrolein to acrylic acid utilizing 8000 hours year. The acrylic acid collector 107 consists of a lower portion and an upper portion having different functions tower an... The defect that the performance of catalyst performance propylene in two steps acid ) the water from the rest the... It is mixed in a process for producing acrylic acid when in reality, propylene first. Used as a standard process involving two reactors in series, utilizing two catalysts. Produce AA, but it is necessary to avoid a danger of combustion in,... Involving two reactors in series, utilizing two separate catalysts gas reserves presents opportunities... Through a line 12, and the mixture was added dropwise to the reaction becomes!, a great energy is required to convert propylene to acrylic acid 107! But the most common one is via the catalytic vapor phase... 2 desired must... Nevertheless, No sufficient research has been undertaken in the second stage, acid. Are also many a acrylic acid production from propylene step to make acrylic acid from propylene to the insufficiency oxygen. Recovered while the acrolein is fed to a second step to make acrylic acid decreases first oxidized to acrolein a. Starting from different feedstocks two portions, one to be introduced into the line 13 from a 5! Portion having different functions and Comparative Examples illustrate the present invention relates to a process making...

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