The adsorbent for gas purification from sulfur and method of its preparation

 

(57) Abstract:

The invention relates to chemistry and oil refining. Proposed sulfur adsorbent containing as an active ingredient manganese oxide as promoters - iron oxide and/or copper oxide and/or chromium oxide and/or tungsten, as a binder is alumina, and the plasticizer is kaolin. We propose a method of preparing sulfur adsorbent comprising a mixture of powders of oxides of manganese, aluminum hydroxide and the compounds listed promoters and additives kaolin, which serves as a plasticizer. This mixture homogenized, subjected to peptization, and the resulting plastic mass is formed by extrusion, and molding the extrudate is subjected to heat treatment: drying and calcination in an oxidizing atmosphere, and then recovery in an environment of hydrogen. The invention allows for a high degree of desulfurization due to the high capacity of the adsorbent. 2 S. and 4 C.p. f-crystals, 1 table.

The invention relates to the field of chemistry and refining, more precisely to the cleaning of impurities sulfur hydrocarbon gases or hydrogen or mixtures of hydrogen and light hydrocarbons (the so-called hydrogen-containing gas = SIVs). More specifically, izopet eticheskikh technological processes, where required complete removal of sulfur compounds from the source of raw materials or intermediates, primarily for the purification of raw materials of the process of catalytic reforming of gasoline fractions of sulfur.

The platinum catalyst reforming process are deactivated in the presence of the feed stream of sulfur compounds which poison the catalyst. Usually latinoreview catalysts allowable sulphur content in raw materials limit concentration from 0.5 to 1.0 million-1depending on the type of catalyst and the reforming unit. The reduced sulfur to lower values is less than 0.5 or even less than 0.1 million-1increases the efficiency of the reforming catalysts, in particular, to increase stability. This is particularly noticeable effect in the case of so-called unbalanced or vysokokremnievykh catalysts, in which the content of rhenium higher content of platinum in 1,5-2,5 times.

Accepted industry method of preparation of raw materials through the process of Hydrotreating (hydrodesulphurization unit) on alumonickelsilicate or aluminoborosilicate catalysts reduces the sulfur content to 0.5 - 5 million-1. More deep removal of sulfur for the acts (adsorbents and catalysts for purification of the raw material reforming of sulfur in the liquid phase by absorption from the stream at a temperature below 200oC. To the most widespread are high-Nickel catalysts containing, as a rule, more than 50% of the Nickel in a mixture with alumina or silica-alumina matrix, and almanegralucie oxide catalysts of different composition. The disadvantage of these contacts is their low total sulfur-retaining capacity at a very low level of absorption of the most difficult to remove and the most toxic thiophene compounds.

Known use as an adsorbent for absorbing sulfur compounds in the gas phase from a mixture of hydrocarbon (gasoline) raw materials and everything neoshamanic Hydrotreating catalysts (alumonickelsilicate and aluminoborosilicate). However, these catalysts are less effective than high-Nickel contacts.

Known also various adsorbents for the purification of the raw material reforming unit from sulfur containing zinc, for example, adsorbents having a composition of aluminium spinel, in which the zinc oxide and aluminum oxide are contained in a molar ratio of 1: 1 and structurally related. These adsorbents catch mainly hydrogen sulfide from circulating SIV, have very low sulfur-retaining capacity, not suitable for cleaning directly ptx2">

It is also known the use of Arsenalnaya sinks by passing a mixture of raw materials (gasoline fraction) and SIVs circulating through the bed of adsorbent at a temperature of 300-400oC. However, under the action of hydrogen chloride gradual sublimation of zinc chloride, which falls on a platinum reforming catalyst and irreversibly poison him. For more effective use of such absorbers is required in the setup diagram to provide a trap - extra canister for trapping hydrogen chloride, which complicates the circuit and unreasonably increases the cost of the node adsorption purification of raw materials from sulfur [U.S. Pat. RF 2094114, class B 01 D 53/04, 1997].

The highest efficiency in the adsorption removal of sulfur from the gas phase have the adsorbents on the basis of oxides of manganese.

Known manganese sulfur adsorbent, which contains 35 to 94%, preferably 50-95% manganese oxide, mainly in the form of MnO. As a binder, which is the matrix for the distribution of active manganese oxide and is used for imparting the desired mechanical strength, provides for the use of such refractory oxides as active alumina, aljumaili the ay extrusion or tabletting, or impregnation of the carrier (binder) solution of manganese compounds with subsequent heat treatment operations [U.S. Pat 4225447, class C 10 C, 25/00, 1980].

Previously hydrotreated feedstock containing, typically, less than 5 million-1organic compounds of sulphur, mixed with circulating SIV containing hydrogen sulfide, is passed through the layer of manganese adsorbent at a temperature of 340-450oC, a pressure of 1-5 MPa and space velocity of the gaseous stream 500-50000 h-1. The residual sulfur content after the adsorbent is less than 0.1 million-1.

Describes the adsorbent, the composition and method of preparation similar claimed, has the following disadvantages: relatively low sulfur-retaining capacity when the content of MnO is less than 90%, insufficient mechanical strength and low degree of removal of organic sulfur compounds, especially of thiophenol.

The closest in composition and method of preparation of the present adsorbent is an adsorbent consisting of a mixture of oxides of manganese and aluminum, the method of preparation which comprises a mixture of manganese oxides and hydroxide and/or aluminum oxide, plasticization of the mixture by peptization with a solution of nitric acid, formok (MnO2in the form of powder with particle size less than 100 microns [U.S. Pat. RF 2079357, CL 01 D 20/06, 1997 - prototype].

As an example, this patent describes the preparation of the adsorbent with a manganese content of 65% in terms of MnO + 35% Al2O3. One of the drawbacks of this adsorbent is insufficient sulfur-retaining capacity, which in the conditions of the pilot testing of 12-16%. Meanwhile, the gas-phase sulfur adsorbent on the basis of the oxides of manganese are applied not only in the reforming units, with Hydrotreating units, but also on the plants, utilizing low-sulfur raw materials (up to 20 million-1S), where the only acceptable from a technical and economic point of view the method of sulfur removal is adsorption. Reduced sulfur-retaining capacity of the adsorbent leads to the necessity of frequent overloads, in particular, to stops installations for the handling of the adsorbent before the necessity of regeneration of the primary reforming catalyst, and hence to a decrease in economic efficiency.

It also describes the adsorbent is not enough to effectively remove thiophene compounds, which are all known adsorbents adsorbed worse than other organic compounds selenia adsorbent for the prototype is the need to use fine powder of manganese dioxide (less than 100 microns) and strict requirements for the content of manganese dioxide in the source material (not less than 70 and not more than 95 wt.%).

To improve the adsorption of careercast and increase the degree of removal of thiophene compounds proposed manganese adsorbent, containing, along with manganese oxide and aluminum oxide promoters: iron oxide and/or copper oxide and/or chromium oxide and/or tungsten in the following specified components, wt.%: manganese oxide - 45 -77 (calculated as MnO), iron oxide, and 0.1 - 30 (Fe2O3), the copper oxide is 0.01 to 2.5 (calculated as CuO), chromium oxide - 0,1-2,0 (per Cr2O3), tungsten oxide is 0.01 to 0.8 (WO3), aluminum oxide (Al2O3) - the rest. For the preparation of the adsorbent of the original manganese oxide charge in the form of a mixture of any of the known modifications of manganese oxide (manganese - in any valence); parent compound of iron - oxide, nitrate or acetate, the original connection of copper oxide CuO (II) or nitrate, the source of the chromium compound is chromic acid (aqueous solution HCrO4), the original connection tungsten - tungsten acid (H2WO4). Fractional composition of the powder source of oxide of manganese has no values; moreover, as a blend component is proposed to use the whole molded granules of adsorbent (retur). This leads to m is P> Finally, for the same purpose is the introduction of small additions of plasticizer - kaolin.

The adsorbent is prepared by mixing powders of manganese oxide and aluminum hydroxide containing up to 5% of plasticizer kaolin, add connections promoters such as iron, copper, chromium, tungsten, peptization of the mixture of these components with a solution of nitric acid under stirring (plasticization), add reture in the form of whole or crushed granules of the same composition, extruding, drying, calcination and recovery of the extrudates. In the ready the recovered adsorbent manganese oxide is a predominantly MnO, aluminum hydroxide enters - Al2O3, connection promoters in the oxides of Fe2O3, CuO, Cr2O3WO3.

Salient features of the proposed adsorbent is present in the composition of the adsorbent promoters: iron oxide (0.1 to 30% Fe2O3), copper oxide (0,01-2,5% CuO), chromium oxide (0,1 - 2,0% Cr2O3) and tungsten oxide (0.01 to 0.8% of WO3), the presence in the composition of the binder of alumina up to 5% of aluminosilicate plasticizer kaolin, and use as a source of manganese compounds in the composition of the adsorbent see the proposed method of preparation of the adsorbent are introduction during the plasticization in the composition of the paste for forming plasticizer - kaolin and adding to the moldable composition 1-25% of the total mass of the powders reture in the form of dried shaped into extrudates of the same composition as the mixture of powders or in the form of powder obtained by grinding these extrudates, or a mixture of extrudates and powder, as well as the introduction of promoters in the composition in the form of the following compounds: iron - oxide, nitrate or acetate, copper oxide or nitrate, chromium and tungsten in the form of the corresponding acids.

There is no known technical solutions essential distinguishing features of the present invention allows to make a conclusion about its novelty.

The proposed adsorbent and method of its preparation allow 2-5% increase adsorption of the sulfur-retaining capacity when removing sulfur compounds from the feedstock for catalytic reforming and 1.5-3 times increase of the degree of removal of thiophene compounds in comparison with the known technical solutions.

These effects are achieved regardless of the composition of the initial mixture of oxides of manganese (this can be, for example, 100% dioxide MnO2and in the use of mixture components in the form of powders or in the form of large particles (extrudates (retur).

That is Otarov, which themselves do not have a higher efficiency in removing teofanov than the oxides of manganese or a mixture of manganese oxide with alumina and other refractory oxides, evidence of non-obviousness of the proposed solution. It is essential that to achieve these effects is not limited to the composition of the initial mixture of oxides of manganese and fractional composition of the starting powder of oxides of manganese.

Industrial applicability of the proposed adsorbent and method of its preparation are illustrated by the examples and the table.

Example 1.

Prepare the adsorbent having the following composition, wt.%: MnO - 50,0; Fe2O3- 20; CuO - 0,5; Al2O3- 29,5. For this mix 61,28 g of powder of manganese oxide (100% MnO2) with a particle size of from 0.1 to 250 μm, 20 g Fe2O3(powder), 0.5 g of CuO (powder) and 39.3 g of powder pseudoboehmite aluminum hydroxide (29.5 g Al2O3+ 9,8 g H2O). Mixing of the powders produced in the mixer of the Werner with Z-shaped blades. Dry mixing without the addition of liquids are within 20 minutes. Then to the mixture of powders add 35 ml of distilled water and 30 ml of nitric acid with a concentration of 700 g/l After mixing about the military dried extrudates (diameter about 2 mm, length 2-7 mm) of the same composition (50% MnO + 20% Fe2O3to + 0.5% CuO + 29.5% Of Al2O3) in an amount of 5% based on the amount of oxides or 10 g of extrudates with loss on ignition (SPT) 50%. To the resulting plastic mass is added 0.5 g of kaolin, stirred for 5 minutes and molded by extrusion. The extrudates are dried at 110oC (4 hours), and then calcined in a stream of dry air at 530-550oC (6 hours). The diameter of the extrudates is 1.9 mm, the strength factor crushing knife with a blade width of 0.1 mm in average 1.8 kg/mm

Before determining careercast adsorbent restore in a stream of hydrogen at 400oC for 8 hours.

The sample quantity of the adsorbent on the test careercast - 30 cm3or about 42, a Test is carried out on a wide gasoline fraction with a sulfur content of 180 mg/kg of raw material. The feed rate is 6.7 h-1(200 cm3/hour). During the test produce a circulation of hydrogen with a ratio of 1000 nl/l of raw materials. Temperature test - 400oC, the pressure is 2 MPa. Determine the sulfur content in the purified product, the last layer of the adsorbent. Sulfur-retaining capacity assessed by the number of absorbed sulfur adsorbent before the breakthrough, which take the sulfur content in the exit stream is ante after the experience.

In addition, determination of total sulfur, i.e., the total amount of the absorbed sulfur present in the raw materials in the form of hydrogen sulfide, mercaptans, sulfides, disulfides and teofanov, determine the content of thiophene sulfur feedstock and refined product to assess the degree of absorption of the most difficult to remove of thiophenol.

In this example, the sulfur-retaining capacity is 20.5%, the extent of absorption of teofanov 60%.

Example 2.

Prepare the adsorbent having the following composition, wt.%: MnO - 77,0; Fe2O3to 0.5; Cr2O3- 0,15; WO3- 0.05 and Al2O3- 22,3. For this mix 77 g of a powder mixture of oxides of manganese, containing 50% dioxide MnO2and 50% of the oxide of Mn2O3, 29,73 g powder pseudoboehmite aluminum hydroxide, as well as of 1.53 g of salt Fe(NO3)3, 2.2 cm3solution of chromic acid HCrO4with a concentration of 100 g/l and 0,054 g of tungstic acid (H2WO4. The mixture is stirred for 25 minutes, then add 30 cm3distilled water and 32 cm3solution of HNO3with a concentration of 650 g/l After stirring for 30 minutes and add 25% retur in the form of dried extrudates, and 1 g of kaolin analogously to example 1, obtained proizvoda test careercast exactly the same as in example 1.

The strength of the extrudates 1.6 kg/mm

Sulfur-retaining capacity of the adsorbent - 23,8%, the extent of absorption of teofanov 70%.

Example 3.

The composition of the produced adsorbent: 70% MnO, 2% Fe2O3, 2% CuO, 2% Cr2O3, 0,5% WO3the rest (23,5%) - Al2O3. The adsorbent is prepared analogously to example 1, but the iron is introduced in the form of acetate (of 4.38 g of Fe(CH3COO)370 g of the oxides of manganese), copper in the form of nitrate (4,72 g of Cu(NO3)2), chromium in the form of a solution of chromic acid (29,1 ml HCrO4with a concentration of 100 g/l), and tungsten in powder form acid, H2WO4(0.54 g).

The powder of manganese oxides is a composition containing 50% MnO2, 20% Mn2O3, 15% Mn3O4and 15% of MnO, and take in the amount of 70 g in terms of MnO (42,9 g MnO2+ 15.6 g Mn2O3+ 11.3 g Mn3O4+ 10,5 g MnO). After peptization and mixing to the plastic mass add 2% of kaolin and 1% retur in the form of milled extrudates prepared in advance and having the same composition as the composition of the mixture of powders. Heat treatment, recovery and the test is carried out as described in example 1.

The average ratio of the strength of the extrudates n Example 4.

The composition of the adsorbent: 65% of MnO, 0.1% Fe2O3the rest, 34,9% aluminum oxide. Manganese oxide is a 100% dioxide MnO2the iron oxide is taken in powder form Fe2O3. The amount of aluminum oxide in the mixture is 34,9 g in 100 g of a mixture of oxides, with half of that amount, 17,45 g take in powder form gamma-alumina, and the other half 17,45 g in terms of oxide or 23,27 g - powder monohydrate pseudoboehmite. The conditions of drying, calcination and recovery are identical to the conditions of example 1, except that recur in the form of a mixture 1: 1 whole dried extrudates and powder injected into the mixing mass in the amount of 25% of the total mass of the oxides and kaolin in the amount of 0.5%.

Before determining careercast adsorbent is reactivated by hydrogen directly in the reactor-adsorber analogously to example 1.

The strength factor of granules - 1.7 kg/mm; adsorption sulfur-retaining capacity to 24.6%, absorption of teofanov - 66%.

Example 5 (the prototype).

The composition of the adsorbent: 65% of oxide of manganese in terms of MnO and 35% Al2O3. To prepare the sample of adsorbent take 70 g of powder of manganese oxides, in which the content of MnO2equal to 72% (the rest is up from 39.5 g of powder pseudoboehmite (the content of Al2O3-30 g), homogenized by stirring, then peptizing 30 cm3solution of nitric acid (C = 700 g/l), and then molded by extrusion, dried and calcined. The ratio of the strength of the extrudates is 1.4 kg/mm After recovery, as described in example 1, the sample is tested in conditions identical to the test conditions of example 1.

Sulfur-retaining capacity of the sample of adsorbent is 14.2%, and the degree of removal of teofanov - 38%.

The data given in examples 1-5, presented in the form of a table.

1. The adsorbent for gas purification from sulfur-containing manganese oxide and a binder alumina, wherein the adsorbent further comprises promoters: iron oxide and/or copper oxide and/or chromium oxide and/or tungsten in the following specified components, wt.%:

Manganese oxide - 45 - 77 in terms of MnO

Iron oxide is 0.1 to 30 in terms of Fe2ABOUT3< / BR>
The copper oxide is from 0.01 to 2.5 in terms of CuO

The chromium oxide is 0.1 to 2.0 in terms of Cr2ABOUT3< / BR>
The tungsten oxide is from 0.01 to 0.8 in terms of WO3< / BR>
Aluminum oxide (Al2ABOUT3) - Rest

2. The adsorbent under item 1, characterized in that the manganese oxide charge in the form of uminia contains up to 5% kaolin by weight of the adsorbent.

4. The method of preparation of the adsorbent for gas purification from sulfur by mixing powders of oxides of manganese and aluminum hydroxide, peptization of the received weight solution of nitric acid, forming, extrusion and heat treatment - drying, calcination, reduction and passivation, wherein the initial mixture of powders add the promoters - iron oxide and/or copper oxide and/or chromium oxide and/or tungsten and plasticizer - kaolin in the amount of 0.5 - 2% of the total mass of the oxides.

5. The method of preparation of the adsorbent for gas purification from sulfur under item 3, wherein the mixture of powders of oxides of manganese, binders, compounds promoters and plasticizer kaolin add retur, coinciding in part with the original composition of the mixture of powders and taken in the form of extrudates, dried at 100 180oC, or powder obtained by grinding these extrudates, or a mixture of these extrudates and powder in any proportion, in the amount of from 1 to 25% by weight of the total mixture.

6. The method of preparation of the adsorbent for gas purification from sulfur under item 3, characterized in that the promoter is injected in the form of the following compounds: iron - oxide, nitrate or acetate, copper - oxide or NITR the

 

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