Prevention of ammonia breakthrough in process of alkane ammoxidation

FIELD: chemical technology.

SUBSTANCE: invention relates to a method for reducing breakthrough fraction of ammonia in the process for manufacturing acrylonitrile. Method involves addition of hydrocarbon taken among the group consisting of propane and isobutene, ammonium and oxygen-containing gas to the bottom reactor compartment with fluidized bed and containing a catalyst for ammoxidation followed by interaction in the presence of indicated catalyst to form acrylonitrile. Method involves addition into reactor in the point lower by flow from feeding alkane of at least one among from C2- to C5-olefins that reacts with at least part of unreacted ammonia and oxygen presenting in the reactor that allows to carry out the significant reducing the ammonia amount presenting in the reaction flow coming out from the reactor. Except for, invention relates to a method for conversion of acrylonitrile manufacture based on propylene raw wherein propylene, ammonia and oxygen react in reactor in the presence the catalyst used in acrylonitrile manufacturing to the process of acrylonitrile manufacturing based on propane raw wherein propane, ammonia and oxygen reacts in the presence of catalyst used in preparing acrylonitrile. Method involves the following stages: (a) replacing the parent propylene-base raw with the propane-base parent raw; (b) addition into reactor in the point lower by flow from feeding alkane of at least one among from C2- to C5-olefin that reacts with at least part of unreacted ammonia and oxygen presenting in the reactor that results to reducing the amount of ammonia presenting in the reaction flow coming out from the reactor, and (c) addition agents for separation, trapping and recycling of unreacted propane to the process.

EFFECT: improved manufacturing method.

13 cl, 19 ex

 

The level of technology

The scope of the invention

The present invention relates to a method for producing Acrylonitrile direct ammoxidation of saturated hydrocarbons (such as propane), ammonia and oxygen in a reactor containing a catalyst for the ammoxidation. In particular, the present invention relates to a significant reduction of unreacted ammonia, ammonium salts derived from unreacted ammonia by-products. In particular, the present invention is the introduction into the reactor With2-C5the olefin, which reacts with unreacted ammonia, which thus leads to the reduction and/or removal of unreacted ammonia from the reaction stream. This substantial reduction of ammonia in the wastewater provides significant environmental and economic benefits.

The present invention has particular applicability when translating chemical enterprises to obtain Acrylonitrile, from raw materials on the basis of propylene in the company to obtain Acrylonitrile, from raw materials on the basis of propane.

Description of the prior art

The production of Acrylonitrile from propane is a secondary technology. Although there are numerous patents disclosing schemes of synthesis and catalysts of this process, commercialization is ia this technology, however, not happened, and Acrylonitrile continue to develop throughout the world through the ammoxidation of propylene (which is more expensive feedstock than propane).

In the case of both technologies as ammoxidation of propylene and propane to Acrylonitrile, ammonia is a necessary raw material. Usually unreacted ammonia remains in the reaction stream, a phenomenon known as "leakage of ammonia. In order to remove unreacted ammonia in commercial production, based on the propylene, the reaction stream is introduced into contact with sulfuric acid, neutralizing the ammonia to form ammonium sulfate, which is then removed from the process in the flow of the waste water, and then collected in a deep tank or subjected to biological treatment.

In fluidized bed processes ammoxidation of propylene to Acrylonitrile, described in US 5 288 473 and 5 457 223, reveals how significant reduction of ammonia in the reaction stream by introducing into the reactor oxygen-rich compounds, preferably, methanol.

The present invention is to solve the problem of leakage of ammonia in the processes ammoxidation of propane or isobutane in the Acrylonitrile.

Another objective of the present invention is to develop a cost-effective process of translation companies on PR is the production of Acrylonitrile from propylene raw material in the company, based on propane or isobutane raw materials.

The invention

The invention is a method of reducing leakage of ammonia in the production of Acrylonitrile from propane and/or isobutane. In particular, the invention is a process for the manufacture of Acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propane and isobutane, ammonia and oxygen-containing gas into the lower part of the reactor with a fluidized bed containing an ammoxidation catalyst, with subsequent interaction of hydrocarbon, ammonia and oxygen in the presence of the specified catalyst to produce Acrylonitrile, the improvement consists in the introduction into the reactor at a point downstream from the feed alkane to at least one from C2to C5the olefin, which reacts with at least part of the unreacted ammonia present in the reactor oxygen to spend a significant reduction of ammonia in the reaction stream exiting the reactor.

The advantage of the process in accordance with the present invention is that it provides a simple and economical way essential to prevent leakage of ammonia (i.e. unreacted ammonia in the reactor with a fluidized bed along with additional pre which gives for the elimination of such by-product as the ammonium sulfate in the production of Acrylonitrile. Removal of ammonium sulfate from the waste stream in the production of Acrylonitrile means that the waste stream does not contain any or contains a minimal amount of ammonium salts. This leads to significant economic advantage of the Acrylonitrile process, especially if you cannot spend the infusion in a deep tank. Without a significant reduction of ammonia in the reaction flow of the wastewater stream exiting the column quenching, will contain ammonium sulfate (NH4)2SO4in high concentrations, making it difficult to process the elimination of these waste waters. The lowering or elimination of ammonium sulfate from the specified stream can make the water suitable for recycling process, which does not require stringent conditions or expensive materials for equipment that also leads to significant economic benefits and environmental protection.

Thus, in accordance with the present invention reduce or eliminate this amount of ammonia that he disappears from the reaction flow and therefore reduced or avoided expenditures required for hardening, regenerative, destruction, or recycling the unreacted ammonia. In addition, the invention provides an additional advantage associated with obtaining the additional useful products from the olefin.

Another embodiment of the present invention is the method of transfer of the production of Acrylonitrile based on the propylene feedstock, in which propylene, ammonia and oxygen react in the reactor in the presence of a catalyst to obtain Acrylonitrile, in the process for obtaining Acrylonitrile on the basis of the propane feedstock, in which propane, ammonia and oxygen react in the presence of a catalyst to obtain Acrylonitrile. This method includes:

(a) the substitution of the feedstock propane feedstock based on propylene,

(b) introducing into the reactor at least one from C2to C5the olefin, which will react with at least part of the unreacted ammonia and oxygen present in the reactor, to basically carry out the reduction of the amount of ammonia in the reaction stream exiting the reactor, and

(C) adding to the process means for separation, recovery and recycling of unreacted propane.

The advantage of this embodiment of the invention consists in the possibility of re-equipment of the plant, using raw materials on the basis of propylene plant using cheaper raw materials on the basis of propane at a total lower cost of capital expenditures required for the construction of a new venture to use the original raw materialnoah propane and maximum use of existing equipment.

A detailed description of the invention

In accordance with the present invention decreases the formation of ammonium sulfate produced during the manufacture of Acrylonitrile by the reaction of propane and/or isobutane, ammonia and oxygen, by adding at least one2-C5the olefin in the reactor. Introduction2-C5the olefin allows essentially full interaction of an excess of ammonia to olefin, which in turn leads essentially to the complete disappearance of ammonium sulfate from the wastewater stream exiting the column hardening plant for the production of Acrylonitrile. Moreover, the reaction With2-C5the olefin with an excess of ammonia provides additional obtain the desired product (for example, the reaction of conversion of propylene to Acrylonitrile).

In the preferred embodiment of the present invention propane, ammonia and air react in the presence of catalyst in the reactor with a fluidized bed to obtain Acrylonitrile. In such reactors propane, ammonia and air are injected into the base or close to the base location of the reactor, the gaseous reactants pass through the catalyst bed, interacting with each other, while having Acrylonitrile. The reaction products, by-products and unreacted raw materials come from the top or almost the Eski upper part of the reactor.

Any catalyst capable of catalyzing the reaction of propane and/or isobutane in contact with ammonia and oxygen, with the formation of Acrylonitrile and/or Methacrylonitrile suitable for the present invention. One such catalyst is a catalyst which has the following General formula:

VvSbmAaDdOx

where As, when present, represents at least one of Sn, Ti, and Fe,

D, when present, represents at least one of Li, Mg, Na, Ca, Sr, BA, Co, Cr, Ga, Ni, Zn, Ge, Nb, Zr, Mo, W, Cu, Te, TA, Se, Bi, Ce, In, As, B, Al and Mn.

V has a value of 1

m has a value from 0.5 to 10

and has a value of from 0 to 10

d has a value from 0 to 10

x represents the amount necessary to satisfy the valence to the other present elements.

These catalysts may be located on a substrate of a suitable carrier, or without it. Usually suitable carriers, which are known as "substrate"include silicon dioxide, aluminum oxide, zirconium dioxide, titanium, and combinations thereof. DIACID silicon is the preferred substrate.

In the embodiment of the present invention With2-C5the olefin may be introduced into the reactor in any suitable point of the stream, downstream from the point at which the propane and/or isobutane is fed into the reactor Preferably, olefin is injected at a point downstream from the feed alkane, where the olefin will be able to react essentially all or all of the excess ammonia, but not to be competitive the main reaction of the alkane ammoxidation occurring in the lower part of the catalytic layer. In one of the embodiments in relation to the fluidized bed reactor containment olefinic feedstock should be more than 20% of the height of the extended layer of the catalyst, preferably localization is more than 50% of the height of the extended layer of the catalyst, more preferably localization is more than 80% of the height of the extended catalyst layer.

Any of from a2to C5the olefin can provide the advantages of the present invention. Propylene is preferred because of its availability and ability to react with oxygen and ammonia to produce Acrylonitrile.

The amount of olefin can vary, but it should be sufficient to react with any excess ammonia slipping into the reaction stream. Any unreacted olefin, as well as any unreacted alkane, falling in the reaction stream can be captured and recycled to the reactor. System recycle hydrocarbon may be based on any known and the prior art method of separating gaseous hydrocarbons from other gaseous components. Suitable techniques include, but are not limited to, cooling and compression (i.e. fractionation) or adsorption by variable pressure and desorption, as disclosed in US 5 532 384, or adsorption at a variable temperature and desorption among others.

The olefin may be injection after or in the presence of an appropriate gas diluent such as nitrogen, steam, air, CO, CO2flue gas from recycling or combinations thereof.

A greater number produced in the world of Acrylonitrile obtained in the fluidized bed reactor. However, the present invention can be implemented not only in the fluidized bed reactor, but also in any reactor capable of maintaining the catalyst in a liquid state, such as the reactor transport lines, a reactor with a vertical pipe or reactor reuse of raw materials. The present invention can also be used reactors fixed bed.

Each catalyst for the ammoxidation of propane operates to some extent in various raw material ratios and operating conditions from the point of view of maximum yield of Acrylonitrile and/or economic conditions. The amount of excess ammonia in the reaction stream exiting the reactor ammoxidation of propane to some extent depends on using the data of the catalyst. The level of olefin, which must be added will vary depending on the type of catalyst and the nature of the reactor. Accordingly, when implementing the present invention, the amount of olefin introduced into the reactor, will be dictated by the conditions and the catalyst. Depending on the catalyst, which operates in the phase depleted in oxygen, it may be necessary to add additional oxygen to the reactor. However, the catalyst will operate in excess oxygen, no need for introduction of additional oxygen into the reactor. Usually any ammoxidation catalyst can be used when implementing the present invention.

As stated previously, each catalyst for ammoxidation of propylene/propane will work to some extent for different ratios of raw materials and process conditions. Suitable process conditions and ratio of raw materials for the production of Acrylonitrile described in US 3,911,089, and 4 873 215. Typical parameters of the reaction are as follows. The temperature in the reactor is between 300 and 600°C. the pressure inside the reactor is between approximately 1 and approximately 10 atmospheres. Ammonia fed into the reactor at a molar ratio to the propane from 0.01 to 5 to 1, preferably from 0.01 to 1 : 1, more preferably from 0.06 is about 0.4 to 1. Oxygen is supplied to the reactor at a molar ratio to the propane from 0.1 to 5 : 1, preferably from 0.1 to 2 to 1, more preferably from 0.1 to 1 to 1. Gas diluent may be fed into the reactor at a molar ratio to the propane from 0 to 100 to 1, preferably from 0 to 10 to 1. Olefin from C2to C5served in a reactor at a molar ratio to the propane from 0.001 to 100 : 1, preferably from 0.01 to 1 : 1, more preferably from 0.01 to 0.1 to 1.

When carrying out the process of the present invention a standard condition of its holding in the loaded catalyst for propylene/propane, in which it is done should not change, but the conditions can be changed depending on the catalyst and raw materials. For example, if the catalyst operates at a low or minimum oxygen content in the environment, there might be a need to increase the amount of oxygen in the reactor to ensure that the process of the present invention proceeds most effectively. This can be achieved by increasing the ratio of oxygen in the raw material or by direct injection of oxygen into the reactor separate means.

The present invention, in particular, is suitable for transfer of the enterprise for the production of Acrylonitrile from raw materials based on propylene feedstock propane. Replacement of raw materials on the basis of impregnated the Jena to cheaper raw materials on the basis of propane greatly reduces the commercial value of Acrylonitrile on the existing commercial production. Further key advantage of the process described here is the ability to transfer the plant with raw materials based on propylene feedstock propane, at a lower investment than those that are required for the construction of a new plant on the basis of a propane feedstock, while making maximum use of existing equipment.

As with current catalysts and technology single pass conversion of propane to Acrylonitrile is less than a single pass conversion of propylene to Acrylonitrile, unreacted propane is usually separated and catch from the reaction stream and then recycle to the reactor. If so, it is a key component in the transfer of the enterprise, based on the propylene, the company, based on propane, is an additional system of pipelines and facilities, associated with the separation, recovery and recycling of propane. Generally, the catalyst used in the reactor must be replaced by the catalyst, more suitable for the ammoxidation of propane to Acrylonitrile. The advantage of the process described in this invention for such factory translations, is that the use of small amounts of propylene to reduce or eliminate the total amount of unreacted ammonia from the reactor pre is appalled by the need to make other modifications nodes during hardening, capture and purification on an existing processing plant Acrylonitrile from propylene. Thus, the existing plant to produce in a single pass of Acrylonitrile from propylene raw material can be economically converted into a factory, which carried out the process with recycle alkangovolo raw material with only a minimal addition of capital equipment. Moreover, such a transfer may be carried out without adverse effects on quality and commercial quality of the products.

And last, the process and method steps described in the present invention is particularly suitable for enterprises for the production of Acrylonitrile based on the propylene, which have been translated into propane raw materials and which, probably, will be stored propylene stock in place or it will be somehow available to the enterprise.

Examples of carrying out the invention

The following examples are given only for purposes of illustration of the process of the present invention.

Comparative Example a

Using the reactor in the form of titanium U-shaped tube, with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts nitrogen/ /0.78 ammonia/2.2 parts of oxygen/2.2 parts of nitrogen/1 part water, at the base of the reactor, with the containing a series of promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.42 h-1. The conversion of propane was 18.2%. The selectivity for Acrylonitrile was 58.1%. The overall selectivity of useful products (i.e. Acrylonitrile, acrolein and acrylic acid) was approximately 58.1%. The number of jumping ammonia amounted to 22.3% of the number of injected ammonia.

Example 1

Using the reactor in the form of titanium U-shaped tube, with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.72 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen/1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.45 h-1. Propylene is introduced into the reactor at 81.4% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.037/1. Conversion of propylene plus propane amounted to 18.6%. The selectivity of useful products from propane and propylene amounted to 57.6% in acrimony the Rila, 0.1% acrolein and 0.3% for acrylic acid (total selectivity for useful product amounted to 58.1%). The number of slipped out of the ammonia is reduced to 14.7% of the number of injected ammonia.

Example 2

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.74 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen/1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.44 h-1. Propylene is introduced into the reactor at 81.4% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.053/1. Conversion of propylene plus propane amounted to 19.1%. The selectivity of useful products from propane and propylene amounted to 57.6% Acrylonitrile, 0.3% acrolein and 1.2% in the acrylic acid (total selectivity for useful product amounted to 59.0%). The number of jumping ammonia decreased to 14.0% of the number of injected ammonia.

Example 3

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inch ( inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.74 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.46 h-1. Propylene is introduced into the reactor at 81.4% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.097/1. Conversion of propylene plus propane amounted to 18.6%. The selectivity of useful products from propane and propylene was 58.6% Acrylonitrile, 1.1% acrolein and 2.9% in the acrylic acid (total selectivity for useful product amounted to 62.6%). The number of slipped out of the ammonia is reduced to 13.9% of the number of injected ammonia.

Example 4

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.71 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propanol the th ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.45 h-1. Propylene is introduced into the reactor at 49.1% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.073/1. Conversion of propylene plus propane amounted to 20.4%. The selectivity of useful products from propane and propylene amounted to 55.3% Acrylonitrile, 0.2% acrolein and 4.0% in the acrylic acid (total selectivity for useful product amounted to 59.5%). The number of slipped out of the ammonia is reduced to 11.1% of the number of injected ammonia.

Example 5

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.69 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.47 h-1. Propylene is introduced into the reactor at 49.1% of the height of the layer of catalyst. The overall ratio of propylene to about the Anu, introduced into the reactor, is 0.103/1. Conversion of propylene plus propane was 21.2%. The selectivity of useful products from propane and propylene amounted to 50.8% Acrylonitrile, 3.9% acrolein and 6.5% acrylic acid (total selectivity for useful product amounted to 61.3%). The number of slipped out of the ammonia is reduced to 8.1% of the number of injected ammonia.

Example 6

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.69 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.50 h-1. Propylene is introduced into the reactor at 49.1% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.140/1. Conversion of propylene plus propane amounted to 23.1%. The selectivity of useful products from propane and propylene amounted to 43.4% Acrylonitrile, 15.7% acrolein and 7.8% in the acrylic acid (total selectivity for useful product amounted to 66.9%). If estvo jumping ammonia is reduced to 5.6% of the number of injected ammonia.

Comparative Example

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.69 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.37 h-1. The conversion of propane was 19.7%. The selectivity for Acrylonitrile was 54.3%. The total selectivity for useful product (i.e. Acrylonitrile, acrolein and acrylic acid) was 56.1%. The number of slipped out of the ammonia is reduced to 16.8% of the number of injected ammonia.

Comparison of this Comparative Example In examples 7 to 10 have shown that the process depending on the materials and conditions that provide low leakage of ammonia (i.e., Comparative Example), also leads to a lower total selectivity to Acrylonitrile. On the contrary adding propylene in the reactor and carrying out the process in accordance with the present invention (examples 7 to 10) total selectivity for AK is isonitrile increases the amount of jumping ammonia then decreases.

Example 7

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.68 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.38 h-1. Propylene is introduced into the reactor at 23.6% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.032/1. Conversion of propylene plus propane amounted to 19.8%. Selectivity to useful products of propane and propylene amounted to 55.7% Acrylonitrile, 0.2% acrolein and 1.7% in the acrylic acid (total selectivity for useful product amounted to 57.6%). The number of slipped out of the ammonia is reduced to 14.3% of the number of injected ammonia.

Example 8

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.67 parts of ammonia/2.2 parts of oxygen/2.2 parts of the nitrogen /1 part water, in the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.52 h-1. Propylene is introduced into the reactor at 23.6% of the height of the layer of catalyst. The overall ratio of propylene to propane introduced into the reactor, is 0.105/1. Conversion of propylene plus propane amounted to 20.0%. Selectivity to useful products of propane and propylene amounted to 53.5% Acrylonitrile, 0.6% acrolein and 3.7% in the acrylic acid (total selectivity for useful product amounted to 57.8%). The number of slipped out of the ammonia is reduced to 10.0% of the number of injected ammonia.

Example 9

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.68 parts of ammonia/2.2 parts of oxygen/2.1 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The top layer contained 70% full loading of the catalyst, the bottom layer contained 30% full loading of the catalyst. Propylene which was introduced between the two layers in a layer of quartz, who served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.35 h-1. The overall ratio of propylene to propane introduced into the reactor, is 0.034/1. Conversion of propylene plus propane amounted to 18.6%. The selectivity of useful products from propane and propylene amounted to 60.3% Acrylonitrile, 0% acrolein and 0.2% of acrylic acid (total selectivity for useful product amounted to 60.5%). The number of slipped out of the ammonia is reduced to 14.8% of the number of injected ammonia.

Example 10

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.67 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst, diluted 50% wt. crushed quartz. The top layer contained 70% full loading of the catalyst, the bottom layer contained 30% full loading of the catalyst. Propylene was introduced between the two layers in a layer of quartz, which served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric the pressure and average hourly volume-mass velocity propane raw materials amounted to 0.35 h -1. The overall ratio of propylene to propane introduced into the reactor, is 0.071/1. Conversion of propylene plus propane was 20.3%. The selectivity of useful products from propane and propylene amounted to 56.3% Acrylonitrile, 0.1% acrolein and 0.4% in the acrylic acid (total selectivity for useful product amounted to 56.8%). The number of slipped out of the ammonia is reduced to 9.6% of the number of injected ammonia.

Comparative Example

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.81 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.45 h-1. The conversion of propane was 20.4%. The selectivity for Acrylonitrile was 55.1%. The total selectivity for useful product (i.e. Acrylonitrile, acrolein and acrylic acid) was 55.9%. The number of slipped out of the ammonia is reduced to 21.7% of the number of injected ammonia.

Example 11

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 du the MOU (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.84 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The top layer contained 20% of full loading of the catalyst, the bottom layer contained 80% full loading of the catalyst. Propylene was introduced between the two layers in a layer of quartz, which served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.36 h-1. The overall ratio of propylene to propane introduced into the reactor, is 0.032/1. Conversion of propylene plus propane amounted to 22.4%. Selectivity of useful products from propane and propylene was 54.5% Acrylonitrile, 0.6% acrolein and 1.6% in the acrylic acid (total selectivity for useful product amounted to 56.7%). The number of slipped out of the ammonia is reduced to 16.9% of the number of injected ammonia.

Comparative Example D

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.82 the t ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, in the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.41 h-1. The conversion of propane was 19.9%. The selectivity for Acrylonitrile was 58.1%. The total selectivity for useful product (i.e. Acrylonitrile, acrolein and acrylic acid) was 58.6%. The number of slipped out of the ammonia is reduced to 23.5% of the number of injected ammonia.

Comparative Example F

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.83 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.41 h-1. The conversion of propane was 20.1%. The selectivity for Acrylonitrile was 58.0%. The total selectivity for useful product (i.e. Acrylonitrile, acrolein and acrylic acid) was 58.6%. The number of slipped out of the reduced ammonia is about 22.5% of the amount of injected ammonia.

Example 12

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.79 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The top layer contained 40% full loading of the catalyst, the bottom layer contained 60% full loading of the catalyst. Propylene was introduced between the two layers in a layer of quartz, which served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.36 h-1. The overall ratio of propylene to propane introduced into the reactor, is 0.047/1. Conversion of propylene plus propane amounted to 22.2%. Selectivity of useful products from propane and propylene amounted to 56.3% Acrylonitrile, 0.1% acrolein and 1.6% in the acrylic acid (total selectivity for useful product amounted to 57.9%). The number of jumping ammonia decreased to 14.0% of the number of injected ammonia.

Example 13

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with control Studio strobe, flash is emnd temperature 480° With the injected gaseous raw material, consisting of 3 parts of propane/0.79 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of the reactor containing the promoted vanadium antimony oxide propane ammoxidation catalyst. The top layer contained 40% full loading of the catalyst, the bottom layer contained 60% full loading of the catalyst. Propylene was introduced between the two layers in a layer of quartz, which served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.36 h-1. The overall ratio of propylene to propane introduced into the reactor, is 0.052/1. Conversion of propylene plus propane amounted to 22.3%. Selectivity of useful products from propane and propylene amounted to 56.2% Acrylonitrile, 0.2% acrolein and 1.9% in the acrylic acid (total selectivity for useful product amounted to 58.3%). The number of slipped out of the ammonia is reduced to 13.2% of the number of injected ammonia.

Example 14

Using the reactor in the form of titanium U-shaped tube with a diameter of 0.5 inches (1 inch = 2.56 cm), placed in a sand bath with controlled temperature 480°With injected gaseous raw material, consisting of 3 parts of propane/0.78 parts of ammonia/2.2 parts of oxygen/2.2 parts of nitrogen /1 part water, at the base of reaction is ora, contains promoted vanadium antimony oxide propane ammoxidation catalyst. The top layer contained 40% full loading of the catalyst, the bottom layer contained 60% full loading of the catalyst. Propylene was introduced between the two layers in a layer of quartz, which served as a mixing chamber for propylene and gas mixture in the reactor. The reactor operates at atmospheric pressure and average hourly volume-mass velocity propane raw materials amounted to 0.44 h-1. The overall ratio of propylene to propane introduced into the reactor, is 0.052/1. Conversion of propylene plus propane amounted to 19.4%. Selectivity of useful products from propane and propylene was 57.0% Acrylonitrile, 0.4% acrolein and 1.3% in the acrylic acid (total selectivity for useful product amounted to 58.7%). The number of slipped out of the ammonia is reduced to 15.5% of the number of injected ammonia.

1. The way to reduce leakage of ammonia in the production of Acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propane and isobutane, ammonia and oxygen-containing gas into the lower part of the reactor with a fluidized bed containing an ammoxidation catalyst, with subsequent interaction in the presence of the specified catalyst to produce Acrylonitrile, characterized in that the reactor is injected at a point below p the current from the feed alkane, at least one from C 2to C5olefins, which reacts with at least part of the unreacted ammonia present in the reactor of oxygen.

2. The method according to claim 1, characterized in that the hydrocarbon is selected from propane.

3. The method according to claim 1, characterized in that With2-C5olefin is a propylene.

4. The method according to claim 1, characterized in that the olefin is introduced into the reactor in the localization of more than at least 20% of the height of the extended catalyst layer.

5. The method according to claim 1, characterized in that the olefin is introduced into the reactor in the localization of more than at least 50% of the height of the extended catalyst layer.

6. The method according to claim 1, characterized in that the olefin is introduced into the reactor in the localization of more than at least 80% of the height of the extended catalyst layer.

7. The method according to claim 1, characterized in that the catalyst has the formula

VvSbmAaDdOx,

where As, when present, represents at least one of Sn, Ti, and Fe;

D, when present, represents at least one of Li, Mg, Na, Ca, Sr, BA, Co, Cr, Ga, Ni, Zn, Ge, Nb, Zr, Mo, W, Cu, Te, TA, Se, Bi, Ce, In, As, B, Al and Mn;

V has a value of 1;

m has a value from 0.5 to 10;

and has a value of from 0 to 10;

d has a value from 0 to 10;

x represents the amount necessary to address what otvorenie requirements valence for other present elements.

8. The translation method of production of Acrylonitrile based on the propylene feedstock, in which propylene, ammonia and oxygen react in the reactor in the presence of a catalyst to produce Acrylonitrile, the Acrylonitrile process on the basis of a propane feedstock, in which propane, ammonia and oxygen react in the presence of a catalyst to obtain Acrylonitrile, including:

(a) the substitution of the feedstock propane feedstock based on propylene;

(b) introducing into the reactor at a point downstream from the feed alkane to at least one from C2to C5the olefin, which reacts with at least part of the unreacted ammonia and oxygen present in the reactor, reducing the amount of ammonia that is present in the reaction stream exiting the reactor, and

(c) adding to the process means for separation, recovery and recycling of unreacted propane.

9. The method according to claim 8, characterized in that the catalyst in the reactor is replaced by a catalyst having the formula

VvSbmAaDdOx,

where As, when present, represents at least one of Sn, Ti, and Fe;

D, when present, represents at least one of Li, Mg, Na, Ca, Sr, Ba, Co, Cr, Ga, Ni, Zn, Ge, Nb, Zr, Mo, W, Cu, Te, TA, Se, Bi, CE, In, As, B, Al and Mn

V has a value of 1;

m has a value from 0.5 to 10;

and has a value of from 0 to 10;

d has a value from 0 to 10;

x represents the amount necessary to satisfy the valence to the other present elements.

10. The method according to claim 8, characterized in that C2-C5olefin is a propylene.

11. The method according to claim 8, characterized in that the olefin is introduced into the reactor in the localization of more than at least 20% of the height of the extended catalyst layer.

12. The method according to claim 8, characterized in that the olefin is introduced into the reactor in the localization of more than at least 50% of the height of the extended catalyst layer.

13. The method according to claim 8, characterized in that the olefin is introduced into the reactor in the localization of more than at least 80% of the height of the extended catalyst layer.



 

Same patents:

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to methods (variants) for producing acrylonitrile and preparing hydrogen cyanide and acetonitrile as co-products. Methods involve addition of hydrocarbon that is taken among propylene or propane, ammonia and oxygen-containing gas to the reaction zone containing a catalyst for oxidative ammonolysis and reaction is carried out at increased temperature to form acrylonitrile, hydrogen cyanide and acetonitrile, and isolation of acrylonitrile, hydrogen cyanide and acetonitrile from reactor also. According to the first variant reaction is carried out in the presence of alcohols mixture containing methanol and a second alcohol among ethanol, propanol or their mixtures wherein the weight ratio of methanol to the second alcohol in alcohols mixture is maintained depending on necessary amounts of hydrogen cyanide and acetonitrile. According to the second variant reaction is carried out in the presence of alcohols mixture containing methanol and ethanol taken in the weight ratio from about 99:1 to 1::99. According to the third variant reaction is carried out in the presence of one or more alcohols taken among crude methanol, crude ethanol or crude propanol. According to the fourth variant reaction is carried out in the presence of one or more crude (C1-C4)-alcohol. Proposed method provides enhancing yield of one or both co-products, i. e. HCN and acetonitrile, formed in producing acrylonitrile.

EFFECT: improved producing method.

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FIELD: industrial organic synthesis.

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EFFECT: enhanced process efficiency.

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The invention relates to an improved method for the recovery and regeneration of unreacted ammonia from the resulting stream containing Acrylonitrile or Methacrylonitrile derived from the reaction zone, where oxygen, ammonia and a hydrocarbon selected from the group consisting of propane and isobutane, interact in a reactor in the presence of a fluidized bed of ammoxidation catalyst at elevated temperature to obtain the corresponding unsaturated nitrile cooling discharge flow from the fluidized bed reactor containing the corresponding nitrile and unreacted ammonia from the first aqueous solution of ammonium phosphate, in which the ratio of ammonium ions (NH+4) to phosphate ions (PO-34) is from about 0.7 to about 1.3, to absorb essentially all of the unreacted ammonia present in stemming the flow reactor for the formation of the second aqueous solution of ammonium phosphate, richer ammonium ions than the first solution, heating the second aqueous solution of ammonium phosphate to elevated temperature sufficient to reduce the amount of ammonium ions in the second solution to essentially the same level present in n the th ammonia, in a fluidized bed reactor

The invention relates to a method for producing olefin-unsaturated NITRILES by the reaction of lower alkanes or alkenes with oxygen and ammonia in the gas phase in the presence of water vapor and a suitable catalyst at elevated temperature in the ammoxidation reactor with the formation at the exit of the hot gaseous stream comprising nitrile, unreacted reagents and by-products, followed by passing hot gaseous flow through the reverse jet scrubber, in which the hot gaseous stream is rapidly cooled, as a result of its contact with the cooling liquid injected countercurrent to the direction of movement of the specified gas flow, with the removal of ammonia, when this gaseous stream is passed through a reverse jet scrubber provided with such a speed that allows you to change to reverse the direction of flow of the injected coolant by evaporation of a part of the injected coolant

The invention relates to an improved catalytic method for the ammoxidation of lower paraffins to obtain unsaturated mononitriles, such as Acrylonitrile and Methacrylonitrile

The invention relates to a method for isolation and purification refinancing nitrile, such as Acrylonitrile

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EFFECT: improved producing method.

21 cl, 2 tbl, 8 ex

FIELD: industrial organic synthesis.

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EFFECT: enhanced process efficiency.

16 cl, 1 dwg

The invention relates to catalysts for the selective decomposition of N2About in a mixture of nitrous gases

The invention relates to a method for producing a catalyst for the (AMM)oxidation of propane or propylene to Acrylonitrile
The invention relates to a method for producing a tin-containing vanadium-antimony catalysts suitable for the catalytic ammoxidation3-C5-paraffins or olefins, more specifically, to obtain catalysts for the ammoxidation of propane or isobutane, or propylene, or isobutylene with obtaining the appropriate,-unsaturated mononitriles, Acrylonitrile or Methacrylonitrile

The invention relates to improved sposobu, allowing virtually eliminate the formation of nitride in the supply piping in the reactor with a fluidized bed of catalyst used in the production of unsaturated NITRILES from the corresponding olefins, NH3and oxygen, according to the way the temperature of the ammonia inside the pipeline is maintained at a level below the temperature of dissociation and/or the temperature of the internal surface of the pipeline is maintained at a level below the temperature at which any monatomic nitrogen can interact with the pipeline for the formation of nitride

The invention relates to a method for the catalytic vapor-phase ammoxidation3-C5olefins to obtain,- unsaturated mononitriles and HCN, and more precisely, the invention relates to a method for the catalytic vapor-phase ammoxidation (1) of propylene to obtain Acrylonitrile and HCN and (2) of isobutylene to obtain Methacrylonitrile and HCN

FIELD: industrial organic synthesis.

SUBSTANCE: process, in which, in particular, acrylonitrile or methacrylonitrile are obtained, comprises reacting hydrocarbon selected from propane, propylene, and isobutylene with ammonia and oxygen source in presence of catalyst in reaction zone at elevated temperature. Reactor effluent containing unsaturated mononitrile is transferred into first column to be cooled therein with the aid of the first water stream. Cooled effluent containing unsaturated mononitrile is transferred into second column wherein it comes into contact with second water stream to absorb unsaturated mononitrile. Unsaturated mononitrile-containing second column effluent is fed into first distillation column to separate crude unsaturated mononitrile from the second water stream and routed to the second distillation column to remove at least some impurities from crude mononitrile, which is transferred into third distillation column to be further purified. Water in the form of steam and/or distilled water is added in amounts 100 to 2000 ppm to side-cut distillate containing purified mononitrile or to bottom stream coming out of the third distillation column. At least part of the latter is recycled into lower section of third distillation column or directly into column below side-cut distillate withdrawal point.

EFFECT: enhanced process efficiency.

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