An ethanolamine multi-stage tubular reaction energy-saving production system and production process

Abstract

The present invention relates to an ethanolamine production process, and in particular to an ethanolamine multi-stage tubular reaction energy-saving production system and production process. In the present invention, a booster pump is arranged after a membrane separation component, and the reaction material pressure and the booster pump cooperate to provide the pressure difference required for membrane separation. After each stage of reaction, most of the water and liquid ammonia are separated from the ethanolamine (monoethanolamine, diethanolamine, triethanolamine) in time, so that the water and ammonia containing less ethanolamine are pressurized by a pump and participate in the next stage of reaction, thereby reducing the reaction chance of monoethanolamine, diethanolamine, triethanolamine and ethylene oxide, and reducing the reaction impurities.

Description

Technical Field

[0001] The invention relates to an ethanolamine production process, and in particular to an ethanolamine multi-stage tubular reaction energy-saving production system and a production process. Background Art

[0002] Monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) are collectively referred to as ethanolamines. Ethanolamines are obtained by the reaction of ethylene oxide and ammonia under water-catalyzed conditions to form monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA). This reaction is a series of addition reactions. Ammonia (NH3) and ethylene oxide (EO) above room temperature, whether in gaseous or liquid form, can accelerate the addition reaction to form monoethanolamine MEA in the presence of a small amount of hydroxyl-containing substances such as water or the product of the reaction itself EA (a collective term for MEA, DEA, and TEA) as a catalyst; MEA will continue to react with EO to form diethanolamine DEA; DEA will also continue to react with EO to form triethanolamine TEA.

[0003] The chemical reaction equation of ethanolamine is as follows:

[0004] ,

[0005] ,

[0006] The existing molar ratio of liquid ammonia to ethylene oxide is usually 3.5 to 10. Excess liquid ammonia needs to be distilled out from the reaction materials after the reaction, and the steam consumption of the distillation separation is relatively large. Summary of the invention

[0007] The purpose of the present invention is to achieve rough separation of water, liquid ammonia and ethanolamine through an ethanolamine multi-stage tubular reaction energy-saving production system, reduce the steam consumption of separating water and ammonia by distillation after the reactor, and reduce the energy consumption per unit product. At the same time, it can also reduce the reaction opportunity of ethylene oxide with monoethanolamine and diethanolamine, greatly increase the proportion of monoethanolamine in the ethanolamine product, and correspondingly reduce the proportion of diethanolamine and triethanolamine, which is convenient for adjusting the proportion of each component in the product and makes it more adaptable to market demand. When the market demand for monoethanolamine decreases, the membrane component is stopped, and even monoethanolamine and diethanolamine are returned to the reactor to increase the proportion of diethanolamine and triethanolamine.

[0008] The technical scheme of the present invention is: an ethanolamine multi-stage tubular reaction energy-saving production system, comprising a pipeline mixer for mixing, a liquid ammonia pipe, a circulating ammonia liquid pipe, and an ethylene oxide pipe are respectively connected to the first pipeline mixer through a mass flow meter, the first pipeline mixer is connected to the first tubular reactor, the first tubular reactor is connected to the first membrane separation component, the clear liquid end of the first membrane separation component is connected to the first circulating ammonia liquid booster pump, the first circulating ammonia liquid booster pump is connected to the second pipeline mixer, the second pipeline mixer is connected to the second tubular reactor, the second tubular reactor is connected to the second membrane separation component, the clear liquid end of the second membrane separation component is connected to the second circulating ammonia liquid booster pump, the second circulating ammonia liquid booster pump is connected to the third pipeline mixer, the third pipeline mixer is connected to the third tubular reactor, the third tubular reactor is connected to the third membrane separation component, the clear liquid end of the third membrane separation component is connected to the third circulating ammonia liquid booster pump, the third circulating ammonia liquid booster pump is connected to the circulating ammonia liquid pipe, and the concentrated liquid end of the first membrane separation component, the concentrated liquid end of the second membrane separation component, and the concentrated liquid end of the third membrane separation component are connected in parallel and then output.

[0009] A mass flow meter is connected between the first circulating ammonia liquid pressure pump and the second pipeline mixer. A mass flow meter is connected between the second circulating ammonia liquid pressure pump and the third pipeline mixer.

[0010] The second pipeline mixer and the third pipeline mixer are also connected to the ethylene oxide pipe.

[0011] A production process using an ethanolamine multi-stage tubular reaction energy-saving production device comprises the following steps: Step 1. Liquid ammonia, circulating ammonia liquid and ethylene oxide are respectively and continuously measured by a mass flow meter and then enter a high-efficiency pipeline mixer first, and then enter a first tubular reactor for reaction. After the first stage of reaction is completed, the material temperature is controlled at 45-60° C. and then enters a first membrane separation component. Ammonia, water and a small amount of ethanolamine flow out from the clear liquid end of the first membrane separation component, and the remaining ammonia, water and ethanolamine flow out from the concentrated liquid end of the membrane separation component and go to the next process ammonia distillation tower after passing through a pressure regulating valve and a mass flow meter;

[0012] Step 2. Ammonia, water and a small amount of ethanolamine flow out from the clear liquid end of the first membrane separation component D, are pressurized by the first booster pump, enter the second pipeline mixer, and then enter the first tubular reactor for reaction. After the second stage of the reaction is completed, the material temperature is controlled at 45-60°C, and then enters the second membrane separation component. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component, and the remaining ammonia, water and ethanolamine flow out from the concentrated liquid end of the membrane separation component, and go to the next process ammonia distillation tower after passing through the pressure regulating valve and mass flow meter;

[0013] Step 3. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component D, are pressurized by the second booster pump, enter the third pipeline mixer, and then enter the third tubular reactor for reaction. After the third stage of reaction, the material temperature is controlled at 45-60°C, and then enters the third membrane separation component. Ammonia liquid flows out from the clear liquid end of the third membrane separation component, is pressurized by the third booster pump, and enters the circulating ammonia liquid pipe to participate in the system circulation. The remaining ammonia, water, and ethanolamine flow out from the concentrated liquid end of the membrane separation component D, pass through the pressure regulating valve and mass flow meter, and then go to the next process ammonia distillation tower.

[0014] The present invention adds a reverse osmosis membrane separation component after the multi-stage tubular reactor, which can achieve rough separation of water, liquid ammonia and ethanolamine, reduce the steam consumption of separating water and ammonia by distillation after the reactor, and reduce the energy consumption per unit product. In the production process, all or part of the reverse osmosis membrane separation components can be activated, or the reverse osmosis membrane separation components can be not activated. When the membrane separation component is activated, compared with the existing multi-stage tubular reactor, the proportion of monoethanolamine in the ethanolamine product is greatly increased, and the proportion of diethanolamine and triethanolamine is correspondingly reduced. It is convenient to adjust the proportion of each component in the product according to the market demand for monoethanolamine, diethanolamine and triethanolamine.

[0015] Regardless of whether the product structure is adjusted, the membrane assembly after the terminal reactor should be activated to ensure that water and liquid ammonia are roughly separated from the reaction products and returned to the first inlet of the reactor to reduce product energy consumption.

[0016] The present invention provides a booster pump after the membrane separation component, and the reaction material pressure and the booster pump cooperate to provide the pressure difference required for membrane separation. Most of the water, liquid ammonia and ethanolamine (monoethanolamine, diethanolamine, triethanolamine) are separated in time after each stage of reaction, so that the water and ammonia containing less ethanolamine are pressurized by the pump and participate in the next stage of reaction, which reduces the reaction opportunity of monoethanolamine, diethanolamine, triethanolamine and ethylene oxide, and can reduce the reaction impurities.

[0017] The molar ratio of feed in each stage of the present invention is liquid ammonia:ethylene oxide≥10, which avoids the polymerization hazard of ethylene oxide, reduces side reactions, generates less impurities, and the proportion of monoethanolamine in the product can reach 60%.

[0018] The present invention sets up a membrane separation component by-line after each stage of the reactor, and the reaction materials can go directly to the next stage of the reactor through the by-line without passing through the membrane component and the booster pump, which is convenient for process adjustment and maintenance.

[0019] The advantages of the present invention compared with the prior art are as follows:

[0020] 1. The process of the present invention provides an energy-saving process for producing ethanolamine, which reduces the problem of high energy consumption caused by the need for distillation separation and reuse of a large amount of ammonia after the reaction.

[0021] 2. The process of the present invention can also significantly increase the proportion of monoethanolamine in the product, making it easier to adjust the product structure. Compared with the original multi-stage tubular reactor, the product proportions of monoethanolamine, diethanolamine and triethanolamine can be more flexibly adjusted to meet market demand.

[0022] 3. Install a membrane separation component after each reactor, and carry out the ammonia and water separation required after the reactor in advance after each reactor, reducing the steam consumption of distillation separation after the reactor. At the same time, the product composition ratio is more flexible and convenient to adjust, and impurities are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the system and process flow of the present invention.

[0024] In the figure: 1-water mass flowmeter, 2-liquid ammonia mass flowmeter, 3-circulating ammonia liquid mass flowmeter, 4-ethylene oxide flowmeter, 5-mixed ethanolamine flowmeter, 5-pressure regulating valve, A-pipeline mixer, B-pipeline reactor, C-circulating ammonia liquid booster pump, D-membrane separation component, 11-water pipe, 12-liquid ammonia pipe, 13-circulating ammonia liquid pipe, 15-ethylene oxide pipe. DETAILED DESCRIPTION

[0025] The invention will be further described below by means of specific embodiments:

[0026] The energy-saving production system of ethanolamine multi-stage tubular reaction comprises a pipeline mixer, a water pipe 11, a liquid ammonia pipe 12, a circulating ammonia liquid pipe 13, and an ethylene oxide pipe 15 are respectively connected to a first pipeline mixer A1 through mass flow meters (1, 2, 3, 4), the first pipeline mixer A1 is connected to a first tubular reactor B1, the first tubular reactor B1 is connected to a first membrane separation component D1, the clear liquid end of the first membrane separation component D1 is connected to a first circulating ammonia liquid booster pump C1, the first circulating ammonia liquid booster pump C1 is connected to a second pipeline mixer A2, the second pipeline mixer A2 is connected to a second tubular reactor B2, the second tubular reactor is connected to The second membrane separation component D2 is connected, the clear liquid end of the second membrane separation component is connected to the second circulating ammonia liquid booster pump C2, the second circulating ammonia liquid booster pump C2 is connected to the third pipeline mixer A3, the third pipeline mixer A3 is connected to the third tubular reactor B3, the third tubular reactor is connected to the third membrane separation component D3, the clear liquid end of the third membrane separation component is connected to the third circulating ammonia liquid booster pump C3, the third circulating ammonia liquid booster pump C3 is connected to the circulating ammonia liquid pipe 13, the concentrated liquid end of the first membrane separation component D1, the concentrated liquid end of the second membrane separation component D2, and the concentrated liquid end of the third membrane separation component D3 are output after being connected in parallel through a pressure regulating valve 6 and a mass flowmeter 5.

[0027] A mass flow meter 3 is connected between the first circulating ammonia liquid booster pump C1 and the second pipeline mixer A2. A mass flow meter 3 is connected between the second circulating ammonia liquid booster pump C2 and the third pipeline mixer A3. The second pipeline mixer and the third pipeline mixer are also connected to the ethylene oxide pipe 4 respectively.

[0028] After the system is installed, first use water to test the pressure. If the water pressure test is qualified, the residual water in the process equipment of the reaction process can be drained, and then an airtightness check is carried out. After the airtightness is qualified, nitrogen is purged and replaced until the nitrogen sample at the exhaust port is consistent with the nitrogen sample content at the inlet, and then the nitrogen discharge valve and the air inlet valve are closed. The entire reaction section is connected, and the liquid ammonia pump is started to inject liquid ammonia from the inlet of the first reactor, and the pressure of the reaction section is slowly raised to 6.0-7.0MPa. After the liquid ammonia fills the reactor, the ammonia evaporation process is carried out, and the liquid ammonia is evaporated through the ammonia evaporation tower and circulated back to the inlet of the liquid ammonia pump to form a large liquid ammonia cycle. While the liquid ammonia is circulating, the reactor jacket is heated with hot water until the required reaction temperature is reached. Then start the catalyst pump (water pump), ethylene oxide pump, etc. respectively, and pump water, ethylene oxide and other materials into the reactor according to the specified flow rate.

[0029] The complete production process includes the following steps:

[0030] Step 1. Liquid ammonia, circulating ammonia liquid, and ethylene oxide are continuously measured by mass flow meters 1, 2, 3, and 4 respectively, and then enter the high-efficiency pipeline mixer A1 first, and then enter the first tubular reactor B1 for reaction. After the first stage of reaction is completed, the material temperature is controlled at 45-60°C, and then enters the first membrane separation component D1. Ammonia, water and a small amount of ethanolamine flow out from the clear liquid end of the first membrane separation component D1, and the remaining ammonia, water, and ethanolamine flow out from the concentrated liquid end of the membrane separation component D1, and go to the next process ammonia distillation tower after passing through the pressure regulating valve 6 and the mass flow meter 5;

[0031] Step 2. Ammonia, water and a small amount of ethanolamine flow out of the clear liquid end of the first membrane separation component D, are pressurized by the first booster pump C1, enter the second pipeline mixer A2, and then enter the first tubular reactor B2 for reaction. After the second stage of the reaction is completed, the material temperature is controlled at 45 to 60 ° C, and then enters the second membrane separation component D2. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component D2, and the remaining ammonia, water and ethanolamine flow out from the concentrated liquid end of the membrane separation component D2, and go to the next process ammonia distillation tower after passing through the pressure regulating valve and the mass flow meter 5;

[0032] Step 3. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component D, are pressurized by the second booster pump C2, enter the third pipeline mixer A3, and then enter the third tubular reactor B3 for reaction. After the third stage of reaction is completed, the material temperature is controlled at 45-60°C, and then enters the third membrane separation component D3. Ammonia liquid flows out from the clear liquid end of the third membrane separation component D3, is pressurized by the third booster pump C3, and enters the circulating ammonia liquid pipe to participate in the system circulation. The remaining ammonia, water, and ethanolamine flow out from the concentrated liquid end of the membrane separation component D, and then pass through the pressure regulating valve and mass flowmeter 5 to the next process ammonia evaporation tower; the post-processing process is conventional technology and process, which will not be repeated here. The following implementation cases are implemented separately on the basis of the above.

[0033] Embodiment 1:

[0034] The first inlet of the reactor pumps in 7.44 t / h of liquid ammonia (including 4 t / h of recycled ammonia for membrane separation after the reaction), 0.38 t / h of water, and 0.9 t / h of ethylene oxide; the second inlet pumps in 0.8 t / h of ethylene oxide; the third inlet pumps in 0.8 t / h of ethylene oxide;

[0035] Only the third membrane separation component is activated, and 4t / h of ammonia is recycled after membrane separation, which can save 2.5t / h of steam consumption. The output of ethanolamine is 3.20t / h, of which monoethanolamine, diethanolamine and triethanolamine account for 55%, 30% and 15% respectively.

[0036] Embodiment 2:

[0037] The first inlet of the reactor pumps 7.42 t / h of liquid ammonia, 0.38 t / h of water, and 1.2 t / h of ethylene oxide, and the membrane separation component after the first reactor is activated; the second inlet pumps 0.8 t / h of ethylene oxide, and the membrane separation component after the second reactor is activated; the third inlet pumps 0.5 t / h of ethylene oxide; the third membrane separation component is not activated, and steam consumption is not saved. The output of ethanolamine is 3.26 t / h, of which monoethanolamine, diethanolamine, and triethanolamine account for 65%, 26%, and 9%, respectively, with the proportion of monoethanolamine increasing.

[0038] Embodiment 3:

[0039] The first inlet of the reactor pumps in 3.4t / h of liquid ammonia (including 1.5t / h of recycled ammonia), 0.2t / h of water, and 0.9t / h of ethylene oxide; the second inlet pumps in 0.8t / h of ethylene oxide; the third inlet pumps in 0.8t / h of ethylene oxide; only the third membrane separation component is activated, and 1.5t / h of recycled ammonia is separated by membrane, which can save 1t / h of steam consumption. The output of ethanolamine is 3.10t / h, of which monoethanolamine, diethanolamine, and triethanolamine account for 38%, 37%, and 25% respectively.

Claims

1. An energy-saving production process for ethanolamine using a multi-stage tubular reaction, characterized in that: include: Step 1. Liquid ammonia, circulating ammonia liquid, and ethylene oxide are respectively continuously measured by mass flow meters and then enter the high-efficiency pipeline mixer first, and then enter the first tubular reactor for reaction. After the first stage of reaction, the material temperature is controlled at 45-60°C, and then enters the first membrane separation component. Ammonia, water and a small amount of ethanolamine flow out from the clear liquid end of the first membrane separation component, and the remaining ammonia, water, and ethanolamine flow out from the concentrated liquid end of the membrane separation component, and go to the next process ammonia distillation tower after passing through the pressure regulating valve and mass flow meter; Step 2. Ammonia, water and a small amount of ethanolamine flow out from the clear liquid end of the first membrane separation component D, are pressurized by the first booster pump, enter the second pipeline mixer, and then enter the first tubular reactor for reaction. After the second stage of the reaction is completed, the material temperature is controlled at 45-60°C, and then enters the second membrane separation component. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component, and the remaining ammonia, water and ethanolamine flow out from the concentrated liquid end of the membrane separation component, and go to the next process ammonia distillation tower after passing through the pressure regulating valve and mass flow meter; Step 3. Ammonia, water and a smaller amount of ethanolamine flow out from the clear liquid end of the second membrane separation component D, are pressurized by the second booster pump, enter the third pipeline mixer, and then enter the third tubular reactor for reaction. After the third stage of reaction, the material temperature is controlled at 45-60°C, and then enters the third membrane separation component. Ammonia liquid flows out from the clear liquid end of the third membrane separation component, is pressurized by the third booster pump, and enters the circulating ammonia liquid pipe to participate in the system circulation; the remaining ammonia, water, and ethanolamine flow out from the concentrated liquid end of the membrane separation component D, pass through the pressure regulating valve and mass flow meter, and then go to the next process ammonia distillation tower; The process adopts an ethanolamine multi-stage tubular reaction energy-saving production system, including a pipeline mixer, wherein a liquid ammonia pipe, a circulating ammonia liquid pipe, and an ethylene oxide pipe are respectively connected to a first pipeline mixer through a mass flow meter, the first pipeline mixer is connected to a first tubular reactor, the first tubular reactor is connected to a first membrane separation component, the clear liquid end of the first membrane separation component is connected to a first circulating ammonia liquid booster pump, the first circulating ammonia liquid booster pump is connected to a second pipeline mixer, the second pipeline mixer is connected to a second tubular reactor, the second tubular reactor is connected to a second membrane separation component, and the second The clear liquid end of the membrane separation component is connected to the second circulating ammonia liquid booster pump, the second circulating ammonia liquid booster pump is connected to the third pipeline mixer, the third pipeline mixer is connected to the third tubular reactor, the third tubular reactor is connected to the third membrane separation component, the clear liquid end of the third membrane separation component is connected to the third circulating ammonia liquid booster pump, the third circulating ammonia liquid booster pump is connected to the circulating ammonia liquid pipe, the concentrated liquid end of the first membrane separation component, the concentrated liquid end of the second membrane separation component, and the concentrated liquid end of the third membrane separation component are connected in parallel and then output, and the second pipeline mixer and the third pipeline mixer are also connected to the ethylene oxide pipe.

2. The energy-saving production process of ethanolamine by multi-stage tubular reaction according to claim 1, characterized in that: A mass flow meter is connected between the first circulating ammonia liquid pressure pump and the second pipeline mixer.

3. The energy-saving production process of ethanolamine by multi-stage tubular reaction according to claim 1, characterized in that: A mass flow meter is connected between the second circulating ammonia liquid pressure pump and the third pipeline mixer.

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