The method of preparation of the adsorbent for the purification of gases and liquids from galogensoderjasimi connections

 

The invention relates to the field of purification from galogensoderjasimi compounds. The method of preparation of the adsorbent containing the oxides of zinc and aluminum, by mixing zinc and aluminium-containing compounds, forming, drying at 50-150oC and calcination at amounts to 400-650oC. the Mixing is carried out in the presence of acetic acid and nitric acid in the amount of 0.5 to 8.0 wt.% and 0.5-2.0 wt. % respectively by weight of zinc oxide. The resulting adsorbent has a high chloroalkali and mechanical strength. 1 C.p. f-crystals, 1 table.

The invention relates to the purification of gases and liquids from galogensoderjasimi compounds and can be used in refining, petrochemical, chemical industry, semiconductor industry, to solve technological problems, protect equipment from corrosion and environmental protection.

To galogensoderjasimi compounds include hydrogen chloride (Hcl), hydrogen fluoride (HF), bromovalerate (NVG), iodovidonum (HY), the actual chlorine, bromine, fluorine, iodine, halogen compounds with other elements. These harmful gases are used, in particular, in the optoelectronic industry and the semiconductor industry and their contact tepelerinde. In the process of catalytic reforming of gasoline fractions on polymetallic catalysts with the aim of obtaining high-octane gasoline chloride (dichloromethane, carbon tetrachloride) is added to the raw material reforming unit to increase the acidity of the catalyst, the excess hydrogen gas reformer used for Hydrotreating petroleum fractions, contains hydrogen chloride, causing corrosion and the formation of ammonium chloride, which clogs the equipment. When the Hydrotreating gasoline and other factions because of the presence in the raw materials and the hydrogen-containing gas halogenated compounds increases the corrosion of the equipment and disrupted the process.

For purification of gases and liquids from the chlorine-containing impurities known adsorbent containing metals of group VIII (iron, Nickel), metal IB group (copper) on the carrier oxide or aluminum hydroxide [French Patent 2776536, publ. 01.10.1999].

The adsorbent is prepared by mixing the compounds of these metals with aluminum hydroxide, followed by molding and heat treatment (drying and calcination).

The disadvantage of this adsorbent and method of its preparation is in a limited area of its application. Good enough to achiev moisture, which promotes the absorption of hydrogen chloride. However, in many cases has to be cleared of chloride deeply drained gas. Thus, the hydrogen-containing gas catalytic reformer contains only 10-30 ppm of moisture.

Known methods of preparation of adsorbents based on the carrier impregnated with the active component, for example the use of alkali deposited on activated charcoal and soda lime, which is a mixture of NaOH and Cao, limestone impregnated with an aqueous solution of sodium hydroxide [Patent Germany 3708039, publ. 06.10.1988] . Disadvantages of using alkaline media due to the relatively low absorption rate, sintering of the adsorbent, causing fouling of the adsorber, the high solubility of active ingredients in water when cleaning wet gas.

The closest in composition and method of preparing the present adsorbent is an adsorbent containing zinc oxide, aluminum oxide and a compound of an alkali metal such as sodium carbonate or potassium bicarbonate and/or sodium, sodium hydroxide. The ratio of aluminum oxide to zinc oxide, expressed as the number of atoms of aluminum to one atom of zinc is in the range of 0.05 to 0.60, and the ratio of atoms of sodium or of potassium on the [U.S. Patent 5378444, publ. 03.01.1995 - prototype]. The adsorbent is prepared by mixing zinc oxide or a compound that decomposes to form zinc oxide, hydroxide or aluminum oxide, and compounds of alkali metal in the mixture, if necessary, add water to obtain a pellet. Further, it is formed in the extruder to obtain extrudates or pellet dried, crushed into powder and tabletirujut with the addition of graphite. The adsorbent can be molded in the form of pellets or particles of irregular shape. The adsorbent is subjected to heat treatment: drying and calcination at temperatures of 110oWith 350oC.

The specified adsorbent used for cleaning of gases from halides such as hydrogen chloride, chlorine, hydrogen fluoride, fluorine, bromovalerate, bromine, DICHLOROSILANE, silicon tetrachloride, trichloride phosphorus, trichloride boron, boron TRIFLUORIDE, tetraploid silicon.

The disadvantage of the proposed adsorbent and method of its preparation is the relatively low capacity of the adsorbent absorbed by the halide. The adsorption capacity of the adsorbent in the purification of gas from the hydrogen chloride can be calculated according to the data presented in tables 1 and 2 of the above patent, based on the number of adsorbent (28,4 cm 328.4 g), velocity flux is enta until the leakage is at a concentration of Hcl 1000 ppm and 1% vol. respectively 6.5% and 11.7% of its mass, although the weight percent of zinc oxide in the adsorbent is 85%. Another disadvantage is the low mechanical strength of the adsorbent.

The purpose of the invention is to remedy these disadvantages.

To improve the mechanical strength and capacity for halogenated compounds, a method for preparation of the adsorbent containing the oxides of zinc and aluminum by mixing zinc oxide or zinc compounds, decompose when heated to form zinc oxide hydroxide and/or aluminum oxide with subsequent molding mass, drying and calcination, the mixture of compounds of zinc and aluminum is carried out with the addition of acetic acid and nitric acid in the amount of 0.5 to 8.0 wt.% and 0.5-2.0 wt.% respectively by weight of zinc oxide (calculated as the concentration of acid 100%), and calcining the adsorbent is carried out at temperatures amounts to 400-650oC.

This method is preferably used for receiving adsorbent containing 50-80 wt.% of zinc oxide.

The proposed method for the preparation of the adsorbent involves the production of adsorbent containing the oxides of zinc and aluminum without the introduction of compounds of an alkali metal, which is provided in the prototype. The alkali metal may be present in the form of the use of the Inca or basic zinc carbonate, which at elevated temperatures decomposes to form zinc oxide. The source of aluminum oxide can serve as its a powder or pellet of aluminum hydroxide, which is when the heat is converted into oxide.

The mixture is stirred, adding these acids, and optionally water, to obtain a plastic mass and formed into extrudates. You can get the adsorbent in the form of beads. The final stage - the heat is drying at temperatures of 50-150oC and calcining at temperatures amounts to 400-650oC.

A significant feature of the method of preparation of the adsorbent is the addition of acetic and nitric acids by mixing compounds of zinc and aluminum in the amount of 0.5 to 8.0 wt.% and 0.5-2.0 wt.% respectively by weight of zinc oxide (calculated as the concentration of acid 100%).

The essential feature is the temperature of calcination of the adsorbent - amounts to 400-650oC.

The advantage of the proposed adsorbent and method of its preparation is a significant increase his chloroalkali 1.1-2.0 times, and therefore in the longer its lifespan. The increased mechanical strength of the adsorbent (adsorbent stronger 1.1-1.5 times) also contributes to the increase in e is containing compounds showed the absence among them of the method of preparation of the adsorbent, the corresponding declared that allows to make a conclusion on the conformity of the proposed technical solution the criterion of novelty.

The reason for the positive influence of acetic and nitric acids and temperature of annealing on the characteristics of the adsorbent is not clear. We can assume the formation of surface nitrates and acetates of zinc, which, decomposing as annealing at the indicated temperatures cause the effect. In any case, the positive influence of the above factors on the capacity of the chlorine and durability is unexpected.

Industrial applicability of the proposed method of preparation of the following examples.

Example 1.

Prepare the adsorbent containing 55% of zinc oxide, aluminum oxide - rest.

To this end take 55 g of powder of zinc oxide with purity 99.8% and 180 g of pellets of aluminum hydroxide containing 25% alumina (loss on ignition at 550oWITH (SPT) - 75%). The mixture is stirred, add 50 cm3water, and then of 1.65 g of acetic acid (100%) and 1.5 g of 55% nitric acid, per 100% nitric acid - 0,82, These values are respectively 3 wt. % and 1.5 wt.% by weight of zinc oxide (calculated as the concentration of acid 100%).

oFor 3 hours at each temperature and calcined in air flow at 500oWith 3 hours.

The resulting extrudates have a diameter of 2.5 mm, the Ratio of the strength of the extrudates to split defined by OST 301-03-01.8-97, is 1.6 kg/mm

Example 2.

Prepare the adsorbent, the composition and method of preparation similar to that shown in example 1, with the difference that the mixture was added 4.4 g of 100% acetic acid and 0.5 g of 55% nitric acid (0.28 g per 100% nitric acid).

These values are respectively 8,0% 0,5% 100% acid by weight of zinc oxide. The ratio of the strength of the extrudates to split 1.2 kg/mm

Example 3.

Prepare the adsorbent containing 50% zinc oxide, aluminum oxide rest. To this end take 50 g of zinc oxide and 71.4 g of a powder of aluminum hydroxide containing 50 g of aluminum oxide (loss on ignition at 550oWITH (SPT) - 30%). The mixture is stirred, add 80 cm3water, 0.25 g of 100% acetic acid and 1.8 g of 55% nitric acid (1.0 g per 100% nitric acid).

These values are, respectively, 0.5% and 2.0% of 100% acid by weight of zinc oxide. All other stages of the preparation is similar to described in example 1. The strength factor ek else. To this end take 80 g of zinc oxide and 80 g of pellets of aluminum hydroxide containing 25 wt.% aluminum oxide. The mixture is stirred, add 70 cm3water, 24,0 g of 100% acetic acid and 2.9 g of 55% nitric acid (1.6 g, per 100% nitric acid). These values are, respectively, 3% acetic and 2% nitric acid by weight of zinc oxide.

All other stages of the preparation is similar to described in example 1. The ratio of the strength of the extrudates to split 1.1 kg/mm

Example 5.

The composition and method of preparation of the adsorbent similar set forth in example 1 with the difference that as the zinc compounds used basic zinc carbonate in the amount of 76, the Ratio of the strength of the extrudates to split 1.2 kg/mm

Example 6.

The composition and method of preparation of the adsorbent similar set forth in example 1 with the difference that the temperature of calcination of the adsorbent is 400oC. the Ratio of the strength of the extrudates to split 1.1 kg/mm

The example shows that when the minimum temperature annealing significantly reduced strength, although chloroalkali remains at a high level.

Example 7.

The composition and method of preparation of the adsorbent is similar to the presentation of the strength of the extrudates to split 1.3 kg/mm

The example illustrates the upper limit of the temperature of annealing of the adsorbent, in which he still can be used for the purpose.

Example 8.

Determine chloroalkali obtained adsorbents prior to breakthrough of hydrogen chloride. To this end the adsorber loaded 10 cm3powdered adsorbent fraction 0.25 to 1.00 mm Through the adsorber at a temperature of 25oAnd atmospheric pressure miss the dry air containing 4 g/m3of hydrogen chloride. Fix the breakthrough time and determine chloroalkali adsorbent percentage of the absorbed chlorine based on the original weight of the adsorbent. The results of determining chloroalkali adsorbents prepared according to examples 1-5 shown in the table.

From the comparison of the data presented in examples 1 and 2, it follows that when the boundary quantities of acid decreases as chloroalkali, and the mechanical strength of the adsorbent, containing 55% zinc.

In that case, when the content of zinc reaches the lower border of the preferred values of 50 wt.%, chloroalkali becomes even below (example 1).

The maximum chloroalkali is achieved at the upper end of the preferred interval content of zinc oxide, but this reduces the mechanical strength of the BPA also get quite good results.

Example 9.

The adsorbent prepared in example 1, have to determine its capacity when cleaning gas from bromovalerate. The test conditions are similar to those described in example 6, but as helium gas is used, which contains bromovalerate at a concentration of 4 g/m3. The capacity of the adsorbent according to the bromine is 34.7 percent.

The example illustrates the suitability of using the proposed adsorbent to absorb other halogenated compounds, in addition to hydrogen chloride.

Claims

1. The method of preparation of the adsorbent for the purification of gases and liquids from galogensoderjasimi compounds containing oxides of zinc and aluminum, by mixing zinc oxide or zinc compounds, decompose when heated to form zinc oxide, hydroxide and/or aluminum oxide with subsequent molding mass, drying and calcination, wherein the mixture of compounds of zinc and aluminum is carried out with the addition of acetic acid and nitric acid in the amount of 0.5 to 8.0 wt. % and 0.5-2.0 wt. percent, respectively, by weight of zinc oxide (calculated as the concentration of acid 100%), and the annealing is carried out in the temperature range amounts to 400-650oC.

2. The method of preparation of the adsorbent under item 1,

 

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