阅读说明：本技术 一种酮连氮水合肼副产物异丙醇的回收利用方法 (Recycling method of ketazine hydrazine hydrate byproduct isopropanol ) 是由 陈尚思 柴进祥 舒帮会 罗浩 于 2019-09-19 设计创作，主要内容包括：本发明涉及一种酮连氮水合肼副产物的回收利用方法,具体公开了一种酮连氮水合肼副产物异丙醇的回收利用方法,将从丙酮中分离出来的含水的异丙醇通入气化器气化为气体,然后通入脱氢反应器,异丙醇脱氢后生成含有丙酮和氢气的高温气体；将所得高温气体与含水的异丙醇换热后送入气液分离器进行气液分离除去氢气,所得液体混合物送入异丙醇分离系统回收丙酮。本发明将从丙酮中分离出来的异丙醇进行催化脱氢生成丙酮重新作为原料供酮连氮合成使用,节约了生产成本,相比将异丙醇作为有机废液处理,废液量减少了90％以上,且脱氢后产物的分离可与现有装置的异丙醇分离系统设备共用,既降低了生产过程中的废物排放,又充分利用了资源,保护了环境。(The invention relates to a recycling method of ketazine hydrazine hydrate by-product, in particular to a recycling method of ketazine hydrazine hydrate by-product isopropanol, which comprises the steps of introducing the water-containing isopropanol separated from acetone into a gasifier to be gasified into gas, then introducing the gas into a dehydrogenation reactor, and generating high-temperature gas containing acetone and hydrogen after the isopropanol is dehydrogenated; and (3) exchanging heat between the obtained high-temperature gas and water-containing isopropanol, sending the high-temperature gas and the water-containing isopropanol into a gas-liquid separator for gas-liquid separation to remove hydrogen, and sending the obtained liquid mixture into an isopropanol separation system to recover acetone. The invention carries out catalytic dehydrogenation on the isopropanol separated from the acetone to generate the acetone which is used as a raw material for synthesizing the ketazine, saves the production cost, reduces the waste liquid amount by more than 90 percent compared with the method of treating the isopropanol as organic waste liquid, and can share the separation of the dehydrogenated product with the isopropanol separation system equipment of the prior device, thereby not only reducing the waste discharge in the production process, but also fully utilizing the resources and protecting the environment.)

1. A recycling method of ketazine hydrazine hydrate byproduct isopropanol is characterized by comprising the following steps:

(1) introducing water-containing isopropanol separated from acetone into a gasifier to be gasified into gas, then introducing the gas into a dehydrogenation reactor, and generating high-temperature gas containing acetone and hydrogen after the isopropanol is dehydrogenated;

(2) and (3) exchanging heat between the obtained high-temperature gas and water-containing isopropanol, sending the high-temperature gas and the water-containing isopropanol into a gas-liquid separator for gas-liquid separation to remove hydrogen, and sending the obtained liquid mixture into an isopropanol separation system to recover acetone.

2. The method for recycling ketazine hydrazine hydrate byproduct isopropanol as claimed in claim 1, wherein the mass percentage of isopropanol in the aqueous isopropanol is 70-85%, and the mass percentage of water is 10-28%.

3. The method for recycling the isopropanol as the by-product of ketazine hydrazine hydrate as recited in claim 1 or 2, wherein the isopropanol separation system in step (2) comprises an acetone recovery tower and an isopropanol separation tower, the liquid mixture is firstly sent to the acetone recovery tower for rectification, and the acetone is recovered from the top of the tower and sent to an acetone recovery tank; and (3) feeding the obtained tower bottom material into an isopropanol separation tower for rectification, recovering the isopropanol containing water from the tower top, and feeding the tower bottom material which is the methyl isobutyl ketone containing water into a waste liquid treatment system.

4. The method for recycling ketazine hydrazine hydrate byproduct isopropanol as claimed in claim 3, wherein the isopropanol separation system is used for rectifying acetone in the acetone recovery tank to remove isopropanol, namely sending the acetone in the acetone recovery tank to the acetone recovery tower for rectification, recovering the acetone from the tower top to the acetone recovery tank, sending the obtained tower bottom material to the isopropanol separation tower for rectification, recovering the water-containing isopropanol from the tower top, exchanging heat with high-temperature gas, sending the water-containing isopropanol to the gasifier for gasification, and recycling the ketazine obtained from the tower bottom to the hydrolysis system of the hydrazine hydrate production line.

5. The method for recycling ketazine hydrazine hydrate byproduct isopropanol as claimed in claim 4, wherein the acetone in the acetone recovery tank is recovered from the hydrolysis system acetone, and when the mass percentage content of the isopropanol in the acetone recovery tank reaches 7% -10%, the acetone is sent to an isopropanol separation system to separate the acetone and the isopropanol.

6. The method for recycling the isopropanol as the by-product of ketazine hydrazine hydrate as claimed in claim 1 or 2, wherein the hydrogen obtained in step (2) is washed and then used as a heat source of heat conducting oil of a gasifier.

7. The method for recycling ketazine hydrazine hydrate byproduct isopropanol as claimed in claim 1 or 2, wherein the temperature of the dehydrogenation reactor is 200-300 ℃.

8. The method for recycling ketazine hydrazine hydrate byproduct isopropanol as claimed in claim 7, wherein the temperature of the dehydrogenation reactor is 200-270 ℃.

Technical Field

The invention relates to a recycling method of a ketazine hydrazine hydrate byproduct, in particular to a recycling method of isopropanol of the ketazine hydrazine hydrate byproduct.

Background

Hydrazine hydrate, also known as: hydrazine hydrate of the formula N₂H₄·H₂O, which is a strong reducing agent, is an important chemical raw material and is also a raw material of medicines, pesticides, dyes, foaming agents, developers and antioxidants; the method is used for deoxidation of boiler water, preparation of high-purity metal, synthesis and reduction of organic compounds, separation of rare elements, and also used for manufacturing rocket fuels and explosives, and the application field of hydrazine hydrate is continuously widened in recent years along with the progress of technology and the development of society. The production method of hydrazine hydrate mainly includes Raschig method, urea method, ketazine method, hydrogen peroxide method and air oxidation method. The production method of hydrazine hydrate mentioned in this invention is ketazine method, which adopts the reaction of acetone, sodium hypochlorite and ammonia to produce intermediate-ketazine, and the hydrolysis of ketazine to produce hydrazine hydrate. The main chemical reaction equation is as follows:

2NaOH+Cl₂→NaCl+NaClO+H₂O

NH₃+NaClO→NH₂Cl+NaOH

2CH₃COCH₃+NH₃+NH₂Cl+NaOH→(CH₃)₂C＝N-N＝(CH₃)₂C+3H₂O+NaCl

(CH₃)₂C＝N-N＝C(CH₃)₂+3H₂O→N₂H₄·H₂O+2CH₃COCH₃

the following side reactions occur during the reaction:

CH₃COCH₃+H+→CH₃CHOHCH₃(isopropyl alcohol)

Isopropanol, also known as 2-Propanol, 2-Propanol or Isopropanol, is a colorless liquid having a melting point of-89.5 deg.C, a boiling point of 82.4 deg.C, and a relative density of 0.785(20/4 deg.C), and is soluble in water, ethanol, ether, acetone, etc., and forms an azeotrope with water, the azeotrope forming composition contains 87.4% (W/W) of Isopropanol, and the azeotropic temperature is 80.37 deg.C.

Isopropanol is generated in the synthesis and hydrolysis parts in the production process of hydrazine hydrate by a ketazine method, and the purity of an acetone solution is reduced along with the increase of the content of the isopropanol, so that the yield of a system is reduced. The function of acetone in ketazine process hydrazine hydrate is that in the process of producing hydrazine hydrate by oxidizing ammonia with sodium hypochlorite, acetone is added to produce ketazine with more stable property than hydrazine hydrate, so that the hydrazine hydrate is prevented from being oxidized by sodium hypochlorite to reduce yield. In the actual production process, the molar ratio of acetone to sodium hypochlorite usually requires that acetone needs to be excessive and has a certain reaction ratio, for example, isopropanol is contained in acetone, so that the concentration of acetone in the reaction solution is reduced, the ratio of the synthesis reaction materials is influenced, and the yield of the synthesis reaction materials is influenced. In the process of producing hydrazine hydrate by the ketazine method, one ton of 80% hydrazine hydrate is produced, the acetone consumption is 30kg, the acetone consumption mainly generates isopropanol by side reaction, the daily consumption of acetone for producing ten thousand tons of ketazine method hydrazine hydrate is 1 ton, and the byproduct isopropanol is 1.25 ton. In order to solve the problem of low system yield caused by the existence of isopropanol, Chinese patent with publication No. CN105399066A discloses a method for improving the yield of hydrazine hydrate by ketazine process, when the mass percentage content of isopropanol in an acetone recovery tank reaches 7% -10%, acetone is sent into an acetone recovery tower for separation, the temperature of the top of the tower is controlled to be 50-60 ℃, the temperature of a tower kettle is controlled to be 80-90 ℃ for rectification, and the acetone obtained at the top of the tower is sent back into the acetone recovery tank; and (3) feeding the tower bottom material into an isopropanol separation tower for separation, rectifying the tower top temperature at 75-82 ℃ and the tower bottom temperature at 90-95 ℃ to obtain isopropanol at the tower top, and recycling the ketazine obtained at the tower bottom to a hydrolysis step of a hydrazine hydrate production line. The method separates isopropanol in recovered acetone, so that the acetone is purified and returned to a system for use, the influence of the accumulation of the content of the isopropanol on a hydrazine hydrate production system is avoided, ketazine in the separated isopropanol is separated, the ketazine is returned to the hydrazine hydrate production system, and the collected isopropanol is sold outside, but the isopropanol and water form an azeotrope, so that only the isopropanol with the concentration of 70-85% can be obtained, wherein the isopropanol still contains the acetone and the ketazine, and the industrial grade isopropanol standard requires that the purity of the isopropanol is more than 99.7%, and cannot reach the industrial grade isopropanol standard, and only can be treated as organic waste liquid, so that the value is low.

Therefore, how to effectively recycle the isopropanol separated from the production process of hydrazine hydrate by the ketazine method is a problem to be solved urgently at present.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for recycling the isopropanol as the by-product of ketazine hydrazine hydrate.

The technical scheme adopted by the invention for solving the technical problems is as follows: a recycling method of ketazine hydrazine hydrate byproduct isopropanol comprises the following steps:

(1) introducing water-containing isopropanol separated from acetone into a gasifier to be gasified into gas, then introducing the gas into a dehydrogenation reactor, and generating high-temperature gas containing acetone and hydrogen after the isopropanol is dehydrogenated;

(2) and (3) exchanging heat between the obtained high-temperature gas and water-containing isopropanol, sending the high-temperature gas and the water-containing isopropanol into a gas-liquid separator for gas-liquid separation to remove hydrogen, and sending the obtained liquid mixture into an isopropanol separation system to recover acetone.

Furthermore, the isopropanol in the water-containing isopropanol accounts for 70-85% by mass, the water accounts for 10-28% by mass, and the balance is acetone and ketazine.

In industrial production, the purity of the raw material isopropanol in the preparation of acetone by catalytic dehydrogenation of isopropanol is required to be more than 99 percent, so that the purity of the prepared acetone can be more than 90 percent, if the content of impurities in the isopropanol is high, the isopropanol needs to be purified and then subjected to catalytic dehydrogenation, otherwise, the impurity removal of the acetone after the catalytic dehydrogenation greatly improves the impurity removal difficulty and energy consumption, so that when the isopropanol with the mass concentration of 70-85 percent separated from the acetone is treated, the cost for purifying the isopropanol is far greater than the economic benefit of the purified isopropanol because the isopropanol contains 10-28 percent of water and still contains acetone and ketazine and cannot reach the industrial grade isopropanol standard, and the isopropanol can only be treated as organic waste liquid and has low value.

The inventor finds that the catalytic dehydrogenation is carried out on the hydrous isopropanol with the isopropanol content of 70-85% and the water content of 10-28%, the concentration of the obtained acetone is more than 50%, the requirement of recovering the acetone in the production of hydrazine hydrate by a ketazine method is met, and the quality of the hydrazine hydrate is not influenced when the obtained acetone is used in the production of hydrazine hydrate after the isopropanol is separated; the catalytic dehydrogenation of the isopropanol is carried out under normal pressure, the reaction temperature is 200-300 ℃, the isopropanol is on the surface of the catalyst, the dehydrogenation absorbs heat to generate acetone, and a large amount of hydrogen is generated, and the specific reaction formula is as follows:

principal reaction (CH)₃)₂CHOH→(CH₃)₂CO+H₂；

At low temperatures, side reactions (CH) occur₃)₂CO+(CH₃)₂CHOH→(CH₃)₂CHCH₂COCH₃+H₂O to methyl isobutyl ketone;

when the temperature is too high, intramolecular dehydration occurs to produce propylene, (CH)₃)₂CHOH→CH₂＝CHCH₃+H₂O；

The side reactions are reversible, so that the side reactions are inhibited by the water, the reaction equilibrium is carried out towards the reactant direction, the selectivity of the generated acetone is higher, the content of byproducts is reduced, the propylene can be particularly prevented from being generated by dehydration in the isopropanol molecule, and the generated acetone containing the water can be used for producing hydrazine hydrate by the ketazine method without special separation in the follow-up process.

Further, the isopropanol separation system in the step (2) comprises an acetone recovery tower and an isopropanol separation tower, wherein the liquid mixture is firstly sent into the acetone recovery tower for rectification, and acetone is recovered from the tower top and sent into an acetone recovery tank; and (3) feeding the obtained tower bottom material into an isopropanol separation tower for rectification, recovering the isopropanol containing water from the tower top, and feeding the tower bottom material which is the methyl isobutyl ketone containing water into a waste liquid treatment system.

Further, the isopropanol separation system is used for rectifying acetone in the acetone recovery tank to remove isopropanol, namely sending the acetone in the acetone recovery tank into an acetone recovery tower for rectification, recovering the acetone from the top of the tower and sending the acetone back to the acetone recovery tank, sending the obtained tower kettle material into an isopropanol separation tower for rectification, recovering the water-containing isopropanol from the top of the tower, exchanging heat with high-temperature gas and then sending the water-containing isopropanol into a gasifier for gasification, and recycling the ketazine obtained from the tower kettle into a hydrolysis system of a hydrazine hydrate production line.

Further, acetone in the acetone recovery tank is recovered from acetone in the hydrolysis system, and when the mass percentage content of isopropanol in the acetone recovery tank reaches 7% -10%, the acetone is sent to an isopropanol separation system to separate the acetone and the isopropanol.

Further, the hydrogen obtained in the step (2) is washed and then used as a heat source of heat conducting oil of the gasifier. The hydrogen is washed to remove the acetone therein, the hydrogen with the purity of more than 99 percent is obtained and used as a heat source of heat conducting oil of the gasifier, and the acetone and the hydrogen decomposed by the byproduct isopropanol are effectively utilized, thereby reducing the recovery cost and realizing the comprehensive utilization of resources.

Further, the temperature of the dehydrogenation reactor is 200-300 ℃. At the reaction temperature of 200-300 ℃, more than 90% of isopropanol is converted into acetone, the mass of the isopropanol in the side reaction is about 10%, and the conversion rate of the isopropanol and the selectivity of the acetone are greatly improved.

Furthermore, the temperature of the dehydrogenation reactor is 200-270 ℃. The reaction temperature is reduced, the side reaction of generating propylene by intramolecular dehydration of isopropanol is further inhibited at the catalytic dehydrogenation reaction temperature of 200-270 ℃, only the side reaction of methyl isobutyl ketone is generated, and the side reaction is inhibited by water in isopropanol, so that the side product in the reaction only has a small amount of methyl isobutyl ketone, and the variety and content of the side product are reduced.

The invention has the beneficial effects that: the invention carries out catalytic dehydrogenation on the isopropanol separated from the acetone to generate the acetone which is used as a raw material for synthesizing the ketazine again, thereby saving the production cost, reducing the waste liquid amount by more than 90 percent compared with the method of treating the isopropanol as organic waste liquid, and the separation of the dehydrogenated product can be shared by the isopropanol separation system equipment of the prior device, thereby not only reducing the waste discharge in the production process, but also fully utilizing the resources and protecting the environment;

compared with the isopropanol product prepared by separating and purifying the isopropanol, the isopropanol product is sold, the isopropanol is converted into the raw material of the ketazine process hydrazine hydrate again, the investment is lower, the method is simpler, and the actual production requirement of the ketazine process hydrazine hydrate is met.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus used in the production method of the present invention;

labeled as: the system comprises a 1-isopropanol storage tank, a 2-preheater, a 3-gasifier, a 4-dehydrogenation reactor, a 5-gas-liquid separator, a 6-acetone separation tower, a 7-condenser, an 8-reflux tank, a 9-reboiler, a 10-isopropanol separation tower, a 11-condenser, a 12-reflux tank and a 13-reboiler.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

(I) isopropanol separation: in the process of hydrazine hydrate aquatic product, acetone is recovered and stored in an acetone recovery tank for reuse, isopropanol is generated in the synthesis and hydrolysis parts in the process of hydrazine hydrate production by ketazine method, and the purity of acetone solution is reduced along with the increase of isopropanol content, which can cause the reduction of system yield. The isopropanol separation system comprises an acetone recovery tower and an isopropanol separation tower, and is used for separating isopropanol in acetone. When the mass percentage content of the isopropanol in the acetone recovery tank reaches 7-10%, sending the acetone into an acetone recovery tower for separation, controlling the temperature of the tower top to be 50-60 ℃ and the temperature of the tower kettle to be 80-90 ℃ for rectification, and sending the acetone obtained at the tower top back into the acetone recovery tank; and (3) feeding the tower bottom material into an isopropanol separation tower for separation, rectifying the tower top temperature at 75-82 ℃ and the tower bottom temperature at 90-95 ℃ to obtain isopropanol with the mass content of 70-85% at the tower top, and recycling the ketazine obtained at the tower bottom to a hydrolysis step of a hydrazine hydrate production line.

(II) recycling isopropanol: introducing the water-containing isopropanol separated from the top of the isopropanol separation tower into a gasifier to gasify the isopropanol into gas, then introducing the gas into a dehydrogenation reactor, wherein the temperature of the dehydrogenation reactor is 200-300 ℃, and the isopropanol is dehydrogenated to generate high-temperature gas containing acetone and hydrogen; exchanging heat between the obtained high-temperature gas and the water-containing isopropanol separated from the top of the isopropanol separating tower, cooling, and then sending the cooled high-temperature gas and the water-containing isopropanol into a gas-liquid separator for gas-liquid separation to remove hydrogen, wherein the hydrogen is washed and then used as a heat source of heat conducting oil of a gasifier; the obtained liquid mixture contains acetone, isopropanol, water and methyl isobutyl ketone (MBK), and is sent into an acetone recovery tower of an isopropanol separation system for rectification, and acetone is recovered from the tower top and sent into an acetone recovery tank; and (3) feeding the obtained tower bottom material into an isopropanol separation tower for rectification, recovering the water-containing isopropanol from the tower top, mixing the isopropanol with the isopropanol obtained in the isopropanol separation process, and then carrying out dehydrogenation recycling, wherein the tower bottom material is water-containing methyl isobutyl ketone and is sent to a waste liquid treatment system.

The reaction formula involved in the catalytic dehydrogenation reaction process of isopropanol is: (CH)₃)₂CHOH→(CH₃)₂CO+H₂

The following side reactions also occur during the catalytic dehydrogenation reaction of isopropanol: (CH)₃)₂CO+(CH₃)₂CHOH→(CH₃)₂CHCH₂COCH₃+H₂O

Wherein the mass of the isopropanol which is subjected to the side reaction is about 10 percent, and 90 percent of the isopropanol is converted into acetone to be reused in a hydrazine hydrate production system. The percentages referred to in the present invention are all percentages by mass unless otherwise specified.