The method of purification of gases of the oxidation of cumene

 

(57) Abstract:

The invention is intended for purification of exhaust gases from organic solvents, namely for cleaning gases oxidation of cumene in the technology of production of acetone and phenol Kukolnik way. The method of purification of gases of the oxidation of cumene to cumene hydroperoxide includes adsorption of cumene first stage at a temperature of 10-40oWith using a hydrophobic adsorbent. After the first stage adsorption exhaust gases of oxidation is served on the second stage of adsorption of methanol using a hydrophilic adsorbent silica gel, fully cation-exchanged zeolite of type X or Y. the first and second stage carry out the desorption of water vapor. Desorbed products of the first stage are returned to the oxidation of cumene. Product desorption second stage - methanol - allocate. The regenerated adsorbent is cooled exhaust purified by the exhaust gases from parallel adsorbers. The invention achieves the degree of cleaning gases from methanol 5 mg/m3. 2 C.p. f-crystals, 2 Il.

The invention relates to a method of cleaning exhaust gases from organic solvents, namely, the purification of gases oxidation of cumene to GI the value of cumene to cumene hydroperoxide oxygen per cubic meter of exhaust gas usually contains from 5 to 2 g of cumene and 0.5 to 0.2 g of methanol.

Maximum allowable content of cumene in air 50 mg/m3, methanol -5 mg/m3.

The industry has traditionally used two methods for removal of cumene oxidation gases: thermal afterburning and adsorption [E. N. Serbinova. Industrial adsorption of gases and vapors. M., High school, 1969, S. 48].

Both are used in the industry allow you to clean exhaust gases from cumene, but ineffective against methanol.

When thermal ignition of gases oxidation the concentration of methanol is reduced by not more than 20 Rel.%, that does not allow the oxidation of exhaust gases emitted into the atmosphere, methanol content level is often above the maximum allowable concentrations. When the adsorption method of cleaning gases, the most widely used adsorbent is activated carbon. The adsorption capacity of coal cumene is industrially acceptable, allowing you to effectively use it for cleaning gases from cumene. Reaching concentrations of cumene after cleaning coal to the required sanitary standards specified adsorbent does not solve the problem of purification of exhaust gases from oxidation of methanol. The reason for this is that adsorbtion only coal as the sole adsorbent to achieve the methanol concentration in the exhaust gases after adsorption at the level of maximum permissible norms is fundamentally impossible.

Proposed in [Application N 93053704, 20.06.96, Russia] the method of cleaning gases oxidation of cumene on industrial zeolite cracking catalysts also does not solve the task of cleaning gases oxidation of methanol, as proposed in this application adsorbents have high adsorption capacity by cumene and low methanol. If the adsorption capacity by cumene industrial zeolite cracking catalysts is - 0,45-0,53 g per 1 g of the adsorbent, the adsorption capacity for methanol does not exceed 0.05 g per 1 g of the adsorbent. With such a low adsorption capacity becomes uneconomical to use these adsorbents for the removal of methanol.

Activated charcoal and industrial zeolite-containing cracking catalysts belong to the hydrophobic adsorbents that can easily adsorb non-polar compounds, such as cumene, with very little or almost no to adsorb polar compounds such as methanol.

The aim of the present invention is to find a method of cleaning gases oxidation of methanol using an adsorbent with high adsorption capacity by methanol, extended service life and stability under what foistware, in particular, such as silica gel, and fully cationization zeolites of type X or Y, which has a high adsorption capacity for methanol. These adsorbents have high mechanical strength and not lose adsorption properties during repeated cycles of adsorption - desorption. The estimated service life of this type of adsorbent in the purification process gases cumene oxidation is at least three years.

Hydrophilic adsorbents in contrast to the hydrophobic - easily adsorb polar compounds and more weakly non-polar.

As in the oxidation of cumene to cumene hydroperoxide oxygen flue exhaust gases usually contain cumene and methanol, for cleaning gases to the maximum permissible norms as cumene, and methanol is necessary to use two types of adsorbents, hydrophobic, having a high selectivity to cumene and low methanol, and hydrophilic - for purification from methanol.

For adsorption of cumene is used hydrophobic adsorbents such as activated carbon or industrial catalysts cracking, and for the adsorption of methanol - adsorbents possessing hydrophilic properties, such as silica gel or fully cationization goal is to be in two stages. Each stage can be represented by its adsorption apparatus or both stages are located in the same device with the location of the two types of adsorbents on different shelves.

At the design stage of adsorption in one device - adsorbents for adsorption of cumene and methanol are placed in a single adsorber on different shelves, preferably first in the course of the flow of gases is located adsorbent for the removal of cumene, the second - adsorbent for purification from methanol.

At the design stage of purification of gases cumene oxidation in two stages in two units - the first stage is preferably placed adsorber with a hydrophobic adsorbent for the removal of cumene in the second stage adsorber with hydrophilic adsorbent for the removal of methanol.

Technological scheme of purification of gases from oxidation of cumene and methanol, decorated in two stages in two devices shown in Fig.1.

The exhaust air from the reactor oxidation of cumene to cumene hydroperoxide having a temperature 95-125oC, is cooled to a temperature of 5-10oC to extract the main quantity of cumene, and then cooled exhaust gases containing cumene 0.15 to 0.4. % methanol of 0.015 to 0.04 wt.% Postup is which stage in the apparatus of the adsorption of methanol. At the first stage for adsorption of cumene is used activated carbon or industrial catalysts cracking, and the second stage for the adsorption of methanol silica or fully cationization zeolites of type X or Y. the Temperature in the adsorbers supported 20-40oC.

In the exhaust into the atmosphere the air after the second stage of adsorption is reached the maximum allowable rate as cumene, and methanol.

Regeneration komornik and methanol water vapor adsorbers performed separately, so that methanol was not included in the recycling and caused no complications at the stage of oxidation of cumene and the stage of selection of target products of acetone and phenol. Desorption is carried out at a temperature of 100-120oC water vapor.

Obtained after desorption of the cumene return in the process. The methanol obtained after desorption, can be defined as a commercial product or with wastewater sent to bioremediation. The content of methanol in aqueous solution after desorption is 4-5 wt.%.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases from parallel adsorbers.

Technological scheme of purification of gases from oxidation to the adsorption of cumene and methanol are located in the same adsorber on different shelves. At first during the flow of gases shelf is a hydrophobic adsorbent for the removal of cumene, on the second shelf - hydrophilic adsorbent for the removal of methanol.

The cooled gases flow oxidation of cumene to cumene hydroperoxide goes first on the first shelf, which is a hydrophobic adsorbent, which selectively adsorbs the cumene, and then depleted cumene exhaust gases are received on the second shelf, which is hydrophilic adsorbent, which selectively adsorbs methanol.

In the exhaust into the atmosphere the air downstream of the adsorber is achieved the maximum allowable rate as cumene, and methanol.

Regeneration of the adsorbents produced water vapor together. Obtained after desorption solution rasclaat water and the organic layer. Methanol is mainly found in the water layer, the concentration of it in the organic layer is extremely small, which allows to avoid complications at the stage of oxidation of cumene and the stage of selection of target products of acetone and phenol.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases from parallel adsorbers.

These benefits and differences between the developed technology is such with reactor oxidation of cumene to cumene hydroperoxide in the amount of 50 thousand m3per hour, with a temperature 95-125oC (in this example 95oC) is cooled to a temperature of 5-10oC (in this example, 5oC) to extract the main quantity of cumene, and then cooled exhaust gases containing cumene 0.15 to 0.4 wt.% and methanol of 0.015 to 0.04 wt.% (in this example, the content of cumene to 0.15 wt.% and methanol of 0.015 wt.%) come in carbon adsorber, the temperature of which is equal to 20-40oC (in this example, 30oC).

The amount of adsorbent - 6 tons. The adsorption time is 8 hours. Desorption is carried out at a temperature of 100-120oC steam. The process of desorption - 8 hours. In the desorption obtained 770 kg of cumene and 5 kg of methanol. The adsorption capacity of coal cumene was 12.9%, the adsorption capacity of methanol to 0.08%. The exhaust into the atmosphere the air contained 20 mg/m3cumene and 0.18 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene, but the maximum allowable rate of methanol exceeded 40 times.

Example 2.

Exhaust gases in the amount of 50 thousand m3per hour with the content of the cumene to 0.15 wt.% and methanol of 0.015 wt.% come on stage adsorption carried out as described in the above description of the proposed two-stage is the quality of the adsorbent is charcoal. The amount of the adsorbent is equal to 5.5 tons. The temperature of the adsorption -10oC. the adsorption Time is 8 hours. Exhaust gases of oxidation after the first stage of adsorption, which was removed cumene, arrive at the second stage. At the second stage as the adsorbent is silica gel. The amount of silica gel - 800 kg Temperature adsorption - 10oC. the adsorption Time is 8 hours. The desorption process at each step is carried out separately. The temperature of the desorption process 100 - 120oC.

In the desorption of the first stage obtained 770 kg of cumene and 5 kg of methanol. Product desorption of the first stage are returned to the oxidation of cumene. As a result of desorption in the second stage received 70 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 5 wt.% of methanol. An aqueous solution of methanol is sent for bioremediation or into methanol as a commodity product. Obtained in the second stage after desorption of the cumene return in the oxidation process.

The adsorption capacity of the silica gel in methanol was 9.4%.

The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases is achieved extremely let the indicate the waste treated by the exhaust gases.

Example 3.

Exhaust gases in the amount of 50 thousand m3per hour with the content of the cumene to 0.15 wt.% and methanol of 0.015 wt.% come on stage adsorption carried out as in example 2. The first stage of the adsorption process as adsorbent is charcoal. The amount of the adsorbent is equal to 6.2 tons. The temperature of the adsorption -40oC. the adsorption Time is 8 hours. Exhaust gases of oxidation after the first stage of adsorption, which was removed cumene, arrive at the second stage. At the second stage as the adsorbent is silica gel. The amount of silica gel - 1100 kg Temperature adsorption -40oC. the adsorption Time is 8 hours. The desorption process is carried out separately. The temperature of the desorption process 100-120oC.

In the desorption of the first stage obtained 770 kg of cumene and 5 kg of methanol. Product desorption of the first stage are returned to the oxidation of cumene. As a result of desorption in the second stage received 70 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 5 wt.% of methanol. An aqueous solution of methanol is sent for bioremediation or into methanol as a commodity product. Obtained in the second stage, after desorption of the cumene return in the process of oxidation. the Eski did not contain cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases.

Example 4.

Exhaust gases in the amount of 50 thousand m3per hour with the content of the cumene to 0.15 wt.%, methanol of 0.015 wt. % and 0.15 wt.% water arrives on stage adsorption carried out as in example 2. The first stage of the adsorption process as adsorbent is charcoal. The amount of the adsorbent is equal to 5.5 tons. The temperature of the adsorption -10oC. the adsorption Time is 8 hours. Exhaust gases of oxidation after the first stage of adsorption, containing methanol and water, come to the second stage. In the second stage as the adsorbent is silica gel. The amount of silica gel to 6 tons. The temperature of the adsorption -10oC. the adsorption Time is 8 hours. The desorption process is carried out separately. The temperature of the desorption process 100-120oC. the desorption of the first stage obtained 770 kg of cumene and 5 kg of methanol. As a result of desorption in the second stage received 70 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 3.5 wt.% of methanol. The adsorption capacity of 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases.

Example 5.

The adsorption process is carried out analogously to example 2, only as the adsorbent in the second stage uses a fully cation-exchanged zeolite CaY. The amount of zeolite CaY - 625 kg

As a result of desorption in the second stage received 70 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 5.1 wt.% of methanol. The adsorption capacity of the zeolite CaY methanol was 12.0%. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases.

Example 6.

The adsorption process is carried out analogously to example 5, only the exhaust gases contain cumene to 0.15 wt.%, methanol of 0.015 wt.% and 0.15 wt.% water. The amount of zeolite CaY - 5500 kg.

As a result of desorption in the second stage received 70 fair capacity of zeolite CaY methanol and water was 15.4%. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

The regenerated adsorbent is cooled exhaust purified by the exhaust gases.

Example 7.

The adsorption process is carried out analogously to example 2, only as the adsorbent in the second stage uses a fully cation-exchanged zeolite NaX. The number of NaX adsorbent - 900 kg.

As a result of desorption in the second stage received 70 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 4.9 wt.% of methanol. The adsorption capacity of zeolite NaX methanol was 8.3%. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

Example 8.

The adsorption process is carried out analogously to example 7, only the exhaust gases contain cumene to 0.15 wt.%, methanol of 0.015 wt.% and 0.15 wt.% water. The amount of zeolite NaX - 6700 kg

As a result of desorption in the second stage received 70 kg Matanat zeolite NaX methanol and water was 12.6%. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

Example 9.

The adsorption process is carried out analogously to example 2, only as the adsorbent in the first stage are used in industrial zeolite-containing catalytic cracking type Zokar. The amount of the adsorbent is equal to 6.5 tonnes. The adsorption time is 8 hours. The temperature of the desorption process 100-120oC. the desorption of the first stage obtained 770 kg of cumene and 15 kg of methanol. The adsorption capacity of industrial zeolite-containing cracking catalyst type Zocar on cumene was 11.8%, the adsorption capacity of methanol is 0.16%. As a result of desorption in the second stage received 60 kg of methanol and 6 kg of cumene. An aqueous solution of methanol after stage desorption contained 4.5 wt. % methanol. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

Example 10.

Exhaust gases in the amount of 50 thousand m3oC. the adsorption Time is 8 hours. The desorption process is carried out jointly. The temperature of the desorption process 100-120oC. the desorption of the resulting solution, which splits into water and the organic layer. The amount of organic layer 780 kg (Amount of cumene in the organic layer 770 kg, the amount of methanol 8 kg, the amount of water - 2 kg) Quantity of water layer 2100 kg (amount of methanol in the aqueous layer -70 kg, the amount of cumene 6 kg). An aqueous solution of methanol after stage desorption contained 3.3 wt. % methanol. The adsorption capacity of coal cumene was 12.9%. The adsorption capacity of the silica gel in methanol was 7.0%. The exhaust into the atmosphere the air is substantially free of cumene and 0.005 g/m3of methanol. In the exhaust into the atmosphere of the exhaust gases reached the maximum allowable rate for cumene and the maximum allowable rate of methanol.

1. The method of purification of gases of the oxidation of cumene to cumene hydroperoxide NYM steam at a temperature of 100-120C, characterized in that the adsorption process at the first stage is carried out at a temperature of 10-40C, the oxidation of exhaust gases after the first stage adsorption served on the second stage of adsorption of methanol using a hydrophilic adsorbent silica gel, fully cation-exchanged zeolite of type X or Y, the methanol is desorbed water vapor and product desorption second stage exhale, desorbed products of the first stage are returned to the oxidation of cumene, the regenerated adsorbent is cooled exhaust purified by the exhaust gases from parallel adsorbers, purified exhaust gases contain practically no cumene, and methanol containing 5 mg/m3.

2. The method according to p. 1, characterized in that the hydrophobic adsorbent in the first stage using activated carbon or industrial zeolite-containing cracking catalysts with high selectivity for cumene and low methanol.

3. The method according to PP.1 and 2, characterized in that the cleaning is performed in each apparatus in two stages with the location of the two types of adsorbents on different shelves.

 

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FIELD: petroleum and gas industries; adsorptive refining of liquid and gas streams from impurities.

SUBSTANCE: the invention is dealt with designs of adsorptive apparatuses and may be used in different branches of industry for adsorptive refining of liquid and gas streams from impurities. The adsorptive apparatus contains a cylindrical body with connecting pipes of the cleaned medium feeding and withdrawal of not adsorbed components, in which there is a partition dividing its space into two communicating chambers, in each of which a sorbent is placed. At that the partition has a cavity limited at least by one flexible wall. The invention allows to increase a purification efficiency of the divided mixture at the expense of exclusion of wall cavities, the use of different sorbents with various properties, to ensure operation of the adsorber with changing while in operation volumes of adsorbent in a corrosive medium and high temperature of a desorption.

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EFFECT: improved quality of neutralization of gases; enhanced operational safety.

2 cl, 6 dwg

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