SU1039534A1 - Method of cleaning synthesis gas from iron pentacarbonyl - Google Patents

Abstract

A METHOD FOR CLEANING SYNTHESIS GAS FROM PENTACARBONYL IRON IMPURITIES by passing it through a layer of silica of a neighing adsorbent, characterized in that, in order to vary the degree of purification, an activated vermiculite with a uniformly porous surface with a body material, as a adsorbent, is used with a uniformly porous surface with a body size that is covered by a vermiculite with a uniform body size, and the size of the purge material can be used as an adsorbent. -80 liters and a specific surface area of 350-450.

Description

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Yu SP

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The invention relates to methods for purifying synthesis gas (CO + Hj from iron pentacarbonyl impurities and can be used in the petrochemical industry in methanol synthesis processes, in oxo-synee, etc.

A number of methods are known for purifying liquid target products of iron pentacarbonyl by oxidation, for example, by sparging air containing ozone through liquid products of oxosynthesis, followed by separating the products of iron pentacarbonyl by filtration 1.

The disadvantages of this method are the reduction of the yield of the target products and the complexity of the technological scheme. This is due to the fact that iron pentacarbonyl formed in synthesis gas as a result of carbonyl corrosion of steel equipment is converted into liquid reaction products, the purification of which is complex and is associated with losses.

The closest to the invention in technical essence and the achieved result is the method of purification of synthesis gas. From iron pentacarbonyl in the process of hydroforming in front of the reaction zone by adsorbing an impurity on molecular sieves 2.

The disadvantage of this method is the low adsorption ability of molecular sieves to low concentrations of iron pentacarbonyl Fe (COjj) contained in the synthesis gas, as a result of which Fe (, CO) 5 breakthrough is observed, and the reaction products must be further purified. In addition, molecular sieves cannot be regenerated by acids after saturation of (CO) -, as this will destroy their structure. The use of molecular sieves in large quantities increases the cost of the cleaning process.

The purpose of the invention is to increase the degree of purification of synthesis gas from iron pentacarbonyl.

The goal is achieved by the fact that according to the method of purification of synthesis gas from pentacarbo impurities, the iron nile passes synthesis gas before the reaction zone through a layer of adsorbent-activated vermiculite, which has a uniformly porous surface with a distribution of pores over their effective radii within 20-80 L and a surface of 350-450 m Vr.

The adsorption properties and surface structure of the sorbents are influenced by the nature and concentration of acids and temperature treatment.

To activate the sorbent in the first stage vermiculite is treated

5-10 fold excess of 5-10% HC1 solution at 50-80 ° C for 4-6 hours and in the second stage an excess of 30-50% HpSO or a mixture of 3 / 5-4 / 5 ob.ch. 30-50% 5 HjSO and 2 / 5-1 / 5 ob.h. 30-50% HNO, at 100-110s for 6-8 hours with further rinsing and calcination.

Such a treatment of vermiculite in 10 two steps permits to carry out metal etching directed along micropores and to obtain sorbents with a uniformly porous surface that exhibit a high adsorption capacity.

After adsorption by the sorbent to 0.8 wt.% Of the Fe ion, a breakthrough of Fe (CO) g is observed. However, despite the breakthrough on the surface of the sorbent, the adsorption and decomposition of iron pentacarbonyl continues.

After us, Pentacarbonyl iron sorbent is subjected to regeneration by etching with an excess of 20-40% at 100-110С, followed by drying and calcination. The regenerated sorbent has almost the same structural properties and, accordingly, selectivity with respect to Fe adsorption (COl5 / as the original.

The selective selectivity of the sorbent with respect to Fe (CO) 5 can be explained by the fact that directed acid etching does not lead to the complete destruction of individual crystalline packets. The etching of metal ions, mainly Fe, Al, Mg, creates, in all likelihood, in such packets, partially free valences. The adsorbed zero-valent iron undergoes interaction and fills free vacancies. The nature of the proposed interaction is confirmed by the fact that the adsorbed iron is in the same coordination state as the iron ion in the original mineral.

EXAMPLE 1.- In the first stage, 100 cm of vermiculite (d 1,2 r / CM J is treated with an excess (SOOO cm 10% HC1 13 for 4-6 hours and a temperature of 60-130 ° C. The product of the first stage of etching is treated with an excess (500 cm) of 30-50% H2SO4 for 6-8 hours and a temperature of 100110 ° C. The product of double etching is washed with distilled water or condensate and dried at 80, calcined at 300-400 ° C. Get the product sorbent.

Example 2 Synthesis gas containing an increased concentration of Fe (CO) is passed through the sorbent layer to determine the sorption capacity of iron pentacarbonyl. The absorption capacity is characterized by the amount of iron ion adsorbed on the surface of the sorbent in the presence of the onset of breakthrough. The content of Fe ion is determined by an atomic adsorption method. The table shows the results for. purification of synthesis gas from pentacarbovil iron on sorbents at its various concentrations and volumetric rates. B-1X-1S + N. At the first stage, vermiculite is treated with 5-10% HC1 at 60-80 ° C, at the second stage - with a mixture of acids consisting of 1 / 5-2 / 5 ob.h. 40% NNOz and 3 / 5-4 / 5 ob.ch. 40% at 100-110 ° C. B-1X-1X. At the first stage, vermiculite is treated as for sample 1, at the second stage - concentrated HC1, 37 g / cm) 100-110 ° C B-1X-1S + N. In the first stage, the cult of verm is treated with 5-10% HC1 with, in the second stage, the treatment is as follows for sample 1. B-1X-1S + N. The first stage of processing. ki is carried out with 2% HC1 at 60-80 ° C, the second as for sample 1. B-1X-1S-N). The first stage of processing is carried out as for sample 1, in the second stage, etching is carried out with a kilogram of lots consisting of 1/2 part.h. 40% HN03 and 1/2 part.h. 40%. B-1X-1S. The first stage of processing is carried out as for sample 1. At

Start of Fe (CO) 5 breakthrough

250 250 124 250 250 250 230 230

No breakthrough

B-1X-1S + N

430

.0.07

0.0042 0.06

0.0014 second stage etching is carried out with 25% HgSO at 100-110 ° C. B-0-1S + N. Vermiculite is processed in one step with a mixture of acids comprising 1 / 2-2 / 5 vol.h. 40% HN03 and 3./5-4/5 ob.h. 40% H SG Thus, uniformly porous sorbents obtained by two-stage directional acidic treatment of vermiculite, unlike molecular sieves, allow the synthesis gas to be completely purified from iron pentacarbonyl impurities. The presence of traces of Fe (.CO) 5 to 2 ppm (detection limit of detection) in the products of the hydroformylation reaction is explained by the interaction of excess CO with the walls of the reactor. The use of the proposed synthesis gas purification method significantly increases the selectivity of promising homogeneous oxosynthesis catalysts and allows non-purification of the reaction products. Using the proposed method allows several times to reduce the cost of the products of oxosynthesis and hydroformylation. A significant economic effect also comes from the use of the proposed method as compared to the molecular sieves used (prototype), since the cost of 1 ton of molecular sieves is 2000 rubles, and the cost of one ton of sorbents is 350 rubles.

Continuation table

Claims (1)

METHOD FOR CLEANING SYNTHESIS GAS FROM PENTACARBONYLON IRON IMPURITIES by passing it through a layer of silica-containing adsorbent, characterized in that, in order to increase the degree of purification, activated vermiculite with a uniformly porous surface with a pore distribution over their effective radii of 20 within the radius is used 80 Ά and a specific 'surface of 350-450 m ² / g. Q0 C © SP ss> I