Green slag-reducing epoxypropane production device and method

Abstract

The invention relates to a green residue-reducing epoxypropane production device and method, and belongs to the field of energy-saving and environment-friendly chemical equipment. The production device disclosed by the invention not only reduces the concentration of hydrogen chloride in chlorohydrin entering a saponification system and the dosage of lime milk in saponification, but also remarkably reduces the amount of filter residues needing to be additionally treated, so that more effective cost control is realized while the production efficiency is improved and green residue reduction is promoted; the production cost of the epoxypropane is greatly reduced, and the economic advantage is remarkable.

Description

Technical Field

[0001] The present invention relates to a propylene oxide production device and method for reducing slag in a green manner, belonging to the field of energy-saving and environmental-friendly chemical processes. Background Art

[0002] Among numerous chemical products, propylene derivatives occupy an important position. Among these derivatives, the output of propylene oxide (PO) is particularly prominent, second only to polypropylene and acrylonitrile, and becoming one of the important varieties of propylene derivatives. As an important organic chemical raw material, propylene oxide is widely used in the production processes of various chemical products such as polyurethane, surfactants, and propylene glycol. Its large market demand and wide application fields make propylene oxide play a crucial role in the global chemical industry. With the continuous progress of chemical technology and the continuous growth of market demand, the output and application prospects of propylene oxide will continue to maintain a strong development momentum.

[0003] Currently, the industrialized methods for synthesizing propylene oxide mainly include the chlorohydrin method, ethylbenzene co-oxidation method, isobutane co-oxidation method, hydrogen peroxide direct oxidation method (HPPO), etc. Among them, the chlorohydrin method is a relatively mature process. It generates chlorohydrin by chlorinating propylene and then obtains propylene oxide by dehydrochlorination. However, this method will produce a large amount of waste residue, causing environmental pollution. The ethylbenzene co-oxidation method generates propylene oxide by co-oxidizing ethylbenzene and oxygen. Although this method reduces the generation of waste residue, it has high energy consumption, and the toxicity of ethylbenzene also poses a threat to the environment and the health of operators. The isobutane co-oxidation method uses isobutane and oxygen to generate propylene oxide under the action of a catalyst. This method has more by-products and requires a high purity of the raw material isobutane. The hydrogen peroxide direct oxidation method directly reacts hydrogen peroxide and propylene to generate propylene oxide. The by-product of this method is only water, which is an environmentally friendly production method. However, the current technology is not yet mature and the cost is relatively high.

[0004] The present invention aims to provide a propylene oxide production device and preparation method for reducing slag in a green manner to improve the environmental pollution and high energy consumption problems existing in the prior art. Summary of the Invention

[0005] To improve the above technical problems, the present invention provides a propylene oxide production device, wherein the production device includes:

[0006] A lime milk preparation device;

[0007] A saponification reaction device located downstream of the lime milk preparation device;

[0008] A sedimentation concentration recycling device and a saponification residue acid addition device located downstream of the saponification reaction device;

[0009] A further reaction device for the concentrated liquid and the chlorohydrin reaction product, which is located upstream of the saponification reaction device and downstream of the sedimentation, concentration and recycling device;

[0010] Wherein, the first discharge end of the sedimentation, concentration and recycling device is respectively connected to the feed end of the saponification reaction device, the feed end of the lime milk preparation device, and the chlorohydrin discharge end of the further reaction device for the concentrated liquid and the chlorohydrin reaction product.

[0011] According to an embodiment of the present invention, the chlorohydrin reaction product refers to the product after the chlorohydrin reaction of the reaction product of propylene with chlorine and water. For example, the chlorohydrin reaction product contains chloropropanol, hydrogen chloride, hypochlorous acid and water.

[0012] According to an embodiment of the present invention, the chloropropanol is monochloropropanol, which may be selected from one or both of, for example, 1-chloro-2-propanol and 2-chloro-1-propanol. Preferably, the chloropropanol contains a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol. Preferably, in the chloropropanol, the molar ratio of 1-chloro-2-propanol to 2-chloro-1-propanol is greater than 1:1, for example, 5:1 to 9.9:1, such as 5:1, 6:1, 7:1, 8:1, 9:1, 9.5:1 or 9.9:1.

[0013] According to an embodiment of the present invention, the saponification reaction device includes a feed end and a discharge end, wherein:

[0014] The feed end includes a chlorohydrin liquid feed port, a chlorohydrin liquid inlet after reacting with the concentrated liquid, a lime milk feed port, and a concentrated liquid feed port connected to the sedimentation, concentration and recycling device;

[0015] The discharge end is connected to the feed end of the sedimentation, concentration and recycling device.

[0016] The further reaction device for the concentrated liquid and the chlorohydrin reaction product is for the concentrated liquid from the sedimentation, concentration and recycling device to be mixed with the chlorohydrin reaction product. The hydrochloric acid in the chlorohydrin reaction product reacts with calcium hydroxide and calcium carbonate in the concentrated liquid, and the generated gas phase is sent to the environmental protection device after being washed with water to further reduce the generation of solid particles in the liquid. The reacted chlorohydrin liquid is transported to the saponification reaction device by a pump.

[0017] According to an embodiment of the present invention, the discharge end of the saponification reaction device produces a mixture including propylene oxide (such as crude propylene oxide), solid waste and waste liquid.

[0018] According to an embodiment of the present invention, the lime milk preparation device includes a feed end and a discharge end, wherein:

[0019] The feed end includes a concentrated liquid feed port connected to the sedimentation, concentration and recycling device and a calcium hydroxide feed port;

[0020] The discharging end is connected to the lime milk feed inlet of the saponification reaction device, so as to carry out the reaction in the saponification reaction device.

[0021] According to an embodiment of the present invention, the lime milk preparation device further includes a calcium hydroxide particle size screening device.

[0022] According to an embodiment of the present invention, the sedimentation, concentration and recycling device is used to sediment, separate and recycle the saponification residue liquid (i.e., a mixture of solid waste and waste liquid) generated by the saponification reaction device, so as to be transported to the feed end of the lime milk preparation device, the feed end of the saponification reaction device, and the chlorohydrin discharging end of the further reaction device for the concentrated liquid and the chlorohydrin reaction product.

[0023] According to an embodiment of the present invention, the sedimentation, concentration and recycling device includes a sedimentation device, a concentration device and a recycling device. Among them, the sedimentation device can be a sedimentation tank known in the art for sedimentation; the concentration device can be an evaporation device or a hydrocyclone known in the art; the recycling device can include pipelines and pumping devices connected to the feed end of the lime milk preparation device, the feed end of the saponification reaction device, and the chlorohydrin discharging end of the further reaction device for the concentrated liquid and the chlorohydrin reaction product.

[0024] According to an embodiment of the present invention, the saponification residue liquid acid adding device includes a feed end and a discharging end, wherein the feed end includes a saponification residue liquid feed inlet and an acid feed inlet. For example, the saponification residue liquid acid adding device is used to mix part of the saponification residue liquid with hydrochloric acid, so that the hydrochloric acid reacts with the alkali (such as calcium hydroxide) in the residue liquid to reduce the dry basis filter cake content. For example, the discharging end of the saponification residue liquid acid adding device can transport the product to a solid-liquid separation device (such as a filtration device, such as another concentration tank), and after separation by the solid-liquid separation device, a clear liquid and solid waste residue are obtained. For example, the filtration device is a filter press.

[0025] According to an embodiment of the present invention, the production device further includes an industrial water treatment device, and the water inlet of the industrial water treatment device is connected to the liquid outlet end of the solid-liquid separation device and the second discharging end of the sedimentation, concentration and recycling device.

[0026] The concentrated liquid at the first discharge end of the sedimentation and concentration recycling device is the recycled material, which respectively enters the saponification reaction device, the lime milk preparation device, and the further reaction device for the concentrated liquid and the chlorohydrin reaction product. The concentrated liquid at the second discharge end of the sedimentation and concentration recycling device enters the industrial water treatment device. In this application, the first discharge end generally refers to the discharge end of the recycled concentrated liquid. In a specific implementation, three branches are provided at the first discharge end. The first branch is connected to the feed end of the saponification reaction device, the second branch is connected to the feed end of the lime milk preparation device, and the third branch is connected to the chlorohydrin discharge end of the further reaction device for the concentrated liquid and the chlorohydrin reaction product.

[0027] According to an embodiment of the present invention, the production device further includes a filter residue treatment device, and the feed end of the filter residue treatment device is connected to the solid material outlet of the solid-liquid separation device.

[0028] The present invention also provides a production method of propylene oxide, including:

[0029] Chloropropanol undergoes a saponification reaction in the system to obtain propylene oxide;

[0030] The system includes lime milk, chlorohydrin liquid, concentrated liquid, and further reaction materials of the concentrated liquid and the chlorohydrin reaction product;

[0031] The concentrated liquid is obtained by sedimentation and concentration of the saponification residue generated by the saponification reaction.

[0032] According to an embodiment of the present invention, the concentration ratio of the saponification residue by sedimentation and concentration is 1:1.05 to 1:8, such as 1:1.08, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7.

[0033] According to an embodiment of the present invention, the concentration includes primary concentration, secondary concentration, or more stages of concentration. For example, the concentration ratio of primary concentration is 1:1.5 to 1:5, and examples are 1:1.5, 1:2, 1:3, 1:4, 1:5; the concentration ratio of secondary concentration is greater than 1:1.2 and does not exceed 1:5, and examples are 1:1.3, 1:1.6, 1:2, 1:3, 1:4, 1:5.

[0034] According to an embodiment of the present invention, the lime milk is known to those skilled in the art, and it is a suspension obtained by mixing calcium hydroxide powder with water or concentrated liquid and reacting.

[0035] According to an embodiment of the present invention, the chlorohydrin liquid is the reaction liquid after the reaction product of propylene and chlorine and water undergoes chlorohydrin reaction.

[0036] According to an embodiment of the present invention, the sedimentation-concentrated saponification residue accounts for 70% to 99% of the total volume of the saponification residue, such as 75%, 80%, 85%, 90%, 92%, 95%.

[0037] According to an embodiment of the present invention, the ratio of the sum of the volumes of the concentrated solution for preparing lime milk, the concentrated solution for further reacting with the chlorohydrin reaction product, and the concentrated solution returned to the system to the volume of the sedimentation-concentrated saponification residue is 1:2 to 1:7, such as 1:3, 1:4, 1:5, 1:6.

[0038] According to an embodiment of the present invention, a part of the saponification residue generated by the saponification reaction is acidified to neutralize the calcium hydroxide therein. For example, hydrochloric acid is added, and the amount of hydrochloric acid used is such that it only reacts with calcium hydroxide and does not react with calcium carbonate. Preferably, the pH value after the saponification residue is mixed and reacted with hydrochloric acid is 8.6 to 9.6 to avoid the emission of greenhouse gas CO2.

[0039] According to an embodiment of the present invention, the flow rate ratio of the acidified saponification residue to the saponification residue separated by sedimentation is 1:3 to 1:8, such as 1:4, 1:5, 1:6, 1:7.

[0040] According to an embodiment of the present invention, by weight, the content of calcium hydroxide in the saponification residue is 0.1 wt% to 0.2 wt%, and the content of calcium carbonate is 0.2 wt% to 0.5 wt%.

[0041] According to an embodiment of the present invention, by weight, the content of calcium hydroxide in the concentrated solution is 0.105 wt% to 1.5 wt%, and the content of calcium carbonate is 0.21 wt% to 5 wt%.

[0042] According to an embodiment of the present invention, the concentrated solutions for preparing lime milk, for further reacting with the chlorohydrin reaction product, and for returning to the system may have the same or different concentrations.

[0043] In one embodiment, the concentrated solution for preparing lime milk is a primary concentrated solution, and the concentrated solutions for further reacting with the chlorohydrin reaction product and for returning to the system are secondary concentrated solutions.

[0044] For example, in the primary concentrated solution, the content of calcium hydroxide is 0.105 wt% to 0.24 wt%, and the content of calcium carbonate is 0.21 wt% to 0.8 wt%;

[0045] In the secondary concentrated solution, the content of calcium hydroxide is 0.5 wt% to 1.5 wt% (such as 0.5 wt% to 1.0 wt%), and the content of calcium carbonate is 1.2 wt% to 5.0 wt% (such as 1.3 wt% to 2.0 wt%).

[0046] According to an embodiment of the present invention, the solid particulate matter in the saponification residue liquid may include one, two or more selected from oxides, hydroxides, carbonates or hydrochloric acid-insoluble substances of metal or non-metal elements.

[0047] According to an embodiment of the present invention, the metal or non-metal element may be selected from one, two or more of Ca, Mg, Fe, Al, and Si.

[0048] According to an embodiment of the present invention, the solid particulate matter in the saponification residue liquid may include one, two or more selected from Ca(OH)2, CaCO3, MgCO3, Fe2O3, Al2O3, and SiO2. For example, the filter residue may include Ca(OH)2, CaCO3, Mg(OH)2, MgCO3, Fe2O3, Al2O3, and SiO2.

[0049] According to an embodiment of the present invention, the solid particulate matter in the saponification residue liquid may also include CaSO4.

[0050] According to an embodiment of the present invention, in the sedimentation and concentration process, the ratio of the recycled amount of the concentrated liquid to the overflow amount of the supernatant liquid may be 1:3 to 1:10, such as 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0051] According to an embodiment of the present invention, the molar ratio of Ca(OH)2 to chloropropanol in the concentrated liquid is higher than 1:1 and lower than 1.5:1, for example (1.05 - 1.3):1, such as 1.05:1, 1.10:1, 1.15:1, 1.20:1, 1.25:1 or 1.30:1.

[0052] According to an embodiment of the present invention, the flow ratio of the concentrated liquid to the chlorohydrin liquid may be 1:5 to 1:20, such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20.

[0053] According to an embodiment of the present invention, the production method of propylene oxide further includes: subjecting the acidified saponification residue liquid to solid-liquid separation, subjecting the obtained liquid phase to industrial water treatment, and subjecting the obtained solid phase to waste residue treatment.

[0054] According to an embodiment of the present invention, the production method of propylene oxide further includes: subjecting other concentrated liquids except for the concentrated liquid used for preparing lime milk, the concentrated liquid used for further reacting with the chlorohydrin reaction product, and the concentrated liquid used for returning to the system to industrial water treatment.

[0055] According to an embodiment of the present invention, the method for producing propylene oxide is carried out in the above production device.

[0056] According to an embodiment of the present invention, the method for producing propylene oxide comprises the following steps:

[0057] (1) Calcium hydroxide powder is mixed with water or concentrated liquid to obtain lime milk;

[0058] (2) Chloropropanol undergoes saponification reaction in the system to obtain propylene oxide;

[0059] The system comprises the lime milk, chlorohydrin liquid, concentrated liquid, and reaction materials of the concentrated liquid and chlorohydrin;

[0060] The concentrated liquid is obtained by sedimentation and concentration of part of the saponification residue produced by the saponification reaction;

[0061] (3) Another part of the saponification residue produced by the saponification reaction is acidified and subjected to solid-liquid separation. The obtained liquid phase is subjected to industrial water treatment, and the obtained solid phase is subjected to waste residue treatment.

[0062] According to an embodiment of the present invention, optionally, the method for producing propylene oxide further comprises the following steps:

[0063] (4) Other concentrated liquids except for the concentrated liquid used for preparing lime milk, the concentrated liquid used for further reacting with the product of the reaction of chlorohydrin, and the concentrated liquid used for returning to the system are subjected to industrial water treatment.

[0064] According to an embodiment of the present invention, the method for producing propylene oxide comprises the following steps:

[0065] (A1) Calcium hydroxide powder is mixed with water or concentrated liquid in the lime milk preparation device to obtain lime milk;

[0066] (A2) Part of the saponification residue generated by the saponification reaction device enters the sedimentation concentration recycling device to obtain concentrated liquid; part of the concentrated liquid enters the lime milk preparation device, the further reaction device of the concentrated liquid and the chlorohydrin reaction product, and the saponification reaction device;

[0067] (A3) Another part of the saponification residue generated by the saponification reaction device enters the saponification residue acid addition device and the solid-liquid separation device. The separated liquid is sent to the industrial water treatment device, and the solid is sent to the waste residue treatment device.

[0068] According to an embodiment of the present invention, optionally, the method for producing propylene oxide further comprises the following steps:

[0069] (A4) Another part of the concentrated liquid of the sedimentation concentration recycling device is treated in the industrial water treatment device.

[0070] Beneficial effects

[0071] The propylene oxide production device and method of the present invention not only reduce the amount of lime milk used in the saponification reaction, but also significantly reduce the amount of filter residue that needs to be additionally treated. Therefore, while improving production efficiency and promoting green residue reduction, more effective cost control is achieved, resulting in a certain reduction in the production cost of propylene oxide of the present invention and significant economic advantages. Description of the drawings

[0072] Figure 1 It is a schematic diagram of the production device of the present invention, where each reference numeral has the following meanings: 1 - saponification reaction device; 2 - sedimentation and concentration recycling device; 3 - lime milk preparation device; 4 - saponification residue acid addition device; 5 - filtration device; 6 - waste residue treatment device; 7 - industrial water treatment device; 8 - further reaction device for concentrated liquid and chlorohydrin reaction product. Detailed implementation manners

[0073] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0074] Example 1: Propylene oxide production device

[0075] This example provides a propylene oxide production device as Figure 1 shown, and this production device includes:

[0076] Lime milk preparation device 3;

[0077] Saponification reaction device 1 located downstream of the lime milk preparation device 3;

[0078] Sedimentation and concentration recycling device 2 and saponification residue acid addition device 4 located downstream of the saponification reaction device 1;

[0079] Further reaction device 8 for concentrated liquid and chlorohydrin reaction product, which is located upstream of the saponification reaction device 1 and downstream of the sedimentation and concentration recycling device 2 at the same time;

[0080] Filtration device 5 and waste residue treatment device 6 located downstream of the saponification residue acid addition device 4;

[0081] Industrial water treatment device 7, which is located downstream of the sedimentation and concentration recycling device 2 and the filtration device 5 at the same time.

[0082] The saponification reaction device 1 includes a feed end and a discharge end, where: the feed end includes a chlorohydrin solution feed port, a chlorohydrin solution inlet after reacting with the concentrated solution, a lime milk feed port, and a concentrated solution feed port connected to the sedimentation and concentration recycling device 2; the discharge end is connected to the feed ends of the sedimentation and concentration recycling device 2 and the saponification residue acid addition device 4. That is, the outputs at the discharge end include propylene oxide (such as crude propylene oxide) and saponification residue (i.e., a mixture of solid waste and waste liquid). A part of the saponification residue enters the sedimentation and concentration recycling device 2, and another part enters the saponification residue acid addition device 4.

[0083] The first discharge end of the sedimentation and concentration recycling device 2 is respectively connected to the feed end of the saponification reaction device 1, the feed end of the lime milk preparation device 3, and the chlorohydrin discharge end of the further reaction device 8 for the concentrated solution and the chlorohydrin reaction product. The second discharge end of the sedimentation and concentration recycling device 2 is connected to the water inlet of the industrial water treatment device 7. The sedimentation and concentration recycling device 2 is used to sediment and separate and recycle the saponification residue generated by the saponification reaction device for transportation to the feed end of the lime milk preparation device 3, the feed end of the saponification reaction device 1, and the chlorohydrin discharge end of the further reaction device 8 for the concentrated solution and the chlorohydrin reaction product. Further, the sedimentation and concentration recycling device includes a sedimentation device, a concentration device, and a recycling device. Among them, the sedimentation device can be a sedimentation tank known in the art for sedimentation; the concentration device can be an evaporation device or a hydrocyclone known in the art; the recycling device can include pipelines and pumping devices connected to the feed end of the lime milk preparation device 3, the feed end of the saponification reaction device 1, and the chlorohydrin discharge end of the chlorohydrin reaction device 8 for the concentrated solution. In a specific implementation, the first discharge end is provided with three branches. The first branch is connected to the feed end of the saponification reaction device, the second branch is connected to the feed end of the lime milk preparation device, and the third branch is connected to the chlorohydrin discharge end of the further reaction device for the concentrated solution and the chlorohydrin reaction product.

[0084] The lime milk preparation device 3 includes a feed end and a discharge end. The feed end includes a concentrated solution feed port connected to the sedimentation and concentration recycling device 2 and a calcium hydroxide feed port. The discharge end is connected to the lime milk feed port of the saponification reaction device 1 so as to carry out a reaction in the saponification reaction device. The calcium hydroxide feed port is optionally connected to a calcium hydroxide particle size screening device.

[0085] In the further reaction device 8 of the concentrated liquid and the chlorohydrin reaction product, the concentrated liquid from the sedimentation and concentration recycling device 2 is mixed with the chlorohydrin reaction product, where the chlorohydrin reaction product refers to the product after the chlorohydrin reaction of the reaction product of propylene with chlorine and water. For example, the chlorohydrin reaction product includes chloropropanol, hydrogen chloride, hypochlorous acid and water. The chloropropanol is monochloropropanol, which contains a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol. The hydrochloric acid in the chlorohydrin reaction product reacts with calcium hydroxide and calcium carbonate in the concentrated liquid, and the generated gas phase is sent to the environmental protection device after being washed with water to further reduce the generation of solid particles in the liquid. The reacted chlorohydrin solution is pumped to the saponification reaction device 1.

[0086] The saponification residue acid addition device 4 includes a feed end and a discharge end, where the feed end includes a saponification residue feed port and an acid feed port. The saponification residue acid addition device 4 is used to mix part of the saponification residue with hydrochloric acid, so that the hydrochloric acid reacts with the alkali (such as calcium hydroxide) in the residue to reduce the dry basis filter cake content. The discharge end of the saponification residue acid addition device transports the product to the filtration device 5, and after solid-liquid separation, a clear liquid and solid waste residues are obtained.

[0087] The water inlet of the industrial water treatment device 7 is connected to the liquid discharge end of the filtration device 5 and the second discharge end of the sedimentation and concentration recycling device 2.

[0088] Example of Propylene Oxide Production Process

[0089] Using the propylene oxide production device of Example 1, based on a 40,000 t / a PO device, propylene oxide (PO) is prepared according to the following process steps:

[0090] S1: The saponification reaction device generates saponification residue. The flow rate of the saponification residue (calcium hydroxide content 0.12 wt%, calcium carbonate content 0.25 wt%) is about 280 m 3 / h, where:

[0091] (1) The saponification residue enters the sedimentation and concentration recycling device for concentration and thickening at a flow rate of Va1. In the concentrated saponification residue (hereinafter referred to as "concentrated liquid"):

[0092] The concentrated liquid P1 is recycled to the lime milk preparation device at a flow rate of Vb1;

[0093] The concentrated liquid P2 is recycled to the saponification reaction device and the further reaction device of the concentrated liquid and the chlorohydrin reaction product at a flow rate of Vb2;

[0094] The remaining supernatant enters the industrial water treatment device;

[0095] (2) The saponification residue without concentration and thickening enters the saponification residue acid addition reaction device at a flow rate of Va2, and hydrochloric acid is added to the saponification residue acid addition reaction device to react with the saponification residue until the pH value is 8.6 - 9.6.

[0096] The residual liquid after the reaction is transported to a filtration device to separate the liquid and solid, where the liquid enters the industrial water treatment device and the solid enters the waste residue treatment device.

[0097] S2: In the lime milk preparation device, calcium hydroxide is added in an amount of 1.48 t / tPO and mixed with the concentrated liquid P1 in step S1 to obtain lime milk.

[0098] S3: The lime milk obtained in step S2 is introduced into the saponification reaction device at a flow rate of Vc1; and the concentrated liquid and the product formed by further reacting the concentrated liquid P2 in step S1 with the chlorohydrin reaction product with a flow rate of Vd1 in the chlorohydrin reaction device (total flow rate Vs = Vb2 + Vd1) are introduced into the saponification reaction device to prepare propylene oxide.

[0099] Among them, the chlorohydrin reaction product with a flow rate of Vd1 is obtained from the chlorohydrin reaction, and its composition is as follows: chlorohydrin: 4.05 wt%, HCl: 1.68 wt%.

[0100] The process conditions of the saponification reaction device are: saponification kettle temperature Tf; top temperature Td; saponification top pressure Pd (absolute pressure), saponification kettle pressure Pf (absolute pressure).

[0101] According to the above process, the process conditions are adjusted in the following Examples 2, 3, Comparative Example 1, and Comparative Example 2, specifically as follows:

[0102]

[0103]

[0104] Note:

[0105] i. The flow rate units in the above table are all m 3 / h;

[0106] ii. In the above Examples 2, 3, and Comparative Example 1, except for the conditions noted, other process steps and conditions are the same.

[0107] iii. In the above Comparative Example 2, in addition to the conditions noted, there are also the following differences:

[0108] (1) The calcium hydroxide content in the saponification residual liquid is 0.12 wt%, and the calcium carbonate content is 0.80 wt%.

[0109] (2) Only the concentrated liquid P1 is prepared, and the concentrated liquid P2 is not prepared, so Vb2 is 0.

[0110] (3) The saponification residual liquid without concentration and thickening does not enter the saponification residual liquid acid addition reaction device, but instead at a flow rate of Va2 (80 m 3 / h) enters the filtration device, where liquid and solid are separated. The obtained liquid enters the industrial water treatment device, and the obtained solid enters the waste residue treatment device.

[0111] The results of the above experiments are summarized in the following table:

[0112]

[0113] The above experimental results show that the device and method of the present invention can increase the production of propylene oxide and reduce the solid waste production to less than 100 kg / tPO. Moreover, the thickened concentrated liquid will reduce the load of the saponification system, reduce the consumption of saponification steam, lime milk, and raw materials.

[0114] The thickened concentrated liquid reacts with hydrochloric acid in chlorohydrin in advance, reducing the hydrochloric acid concentration in the chlorohydrin solution and increasing the reaction probability of lime milk with chlorohydrin in the chlorohydrin solution. This not only improves the efficiency of the saponification system and contributes to the good operation of the saponification system but also avoids the emission of greenhouse gases.

[0115] In summary, the production device of the present invention not only reduces the hydrogen chloride concentration in the chlorohydrin solution and the consumption of lime milk in the saponification reaction but also significantly reduces the amount of filter residue that needs to be additionally treated. Therefore, while improving production efficiency and promoting green residue reduction, it also achieves more effective cost control, greatly reducing the production cost of propylene oxide of the present invention and showing significant economic advantages.

[0116] The above has given an exemplary description of the implementation mode of the technical solution of the present invention. It should be understood that the protection scope of the present invention is not limited to the above implementation mode. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the claims of this application.

Claims

1. A production device for propylene oxide, characterized in that, The production device includes: A lime milk preparation device; A saponification reaction device located downstream of the lime milk preparation device; A sedimentation concentration recycling device and a saponification residue acid addition device located downstream of the saponification reaction device; A further reaction device for the concentrated liquid and the chlorohydrin reaction product located upstream of the saponification reaction device and downstream of the sedimentation concentration recycling device; Wherein, the first discharge end of the sedimentation concentration recycling device is respectively connected to the feed end of the saponification reaction device, the feed end of the lime milk preparation device, and the chlorohydrin discharge end of the further reaction device for the concentrated liquid and the chlorohydrin reaction product.

2. The production device according to claim 1, wherein The saponification reaction device includes a feed end and a discharge end, wherein: The feed end includes a chlorohydrin liquid feed port, a chlorohydrin liquid inlet after reacting with the concentrated liquid, a lime milk feed port, and a concentrated liquid feed port connected to the sedimentation concentration recycling device; The discharge end is connected to the feed end of the sedimentation concentration recycling device; And / or, the discharge end of the saponification reaction device produces a mixture including propylene oxide, solid waste, and waste liquid.

3. The production device according to claim 1, characterized in that, The lime milk preparation device includes a feed end and a discharge end, wherein: The feed end includes a concentrated liquid feed port connected to the sedimentation concentration recycling device and a calcium hydroxide feed port; The discharge end is connected to the lime milk feed port of the saponification reaction device, so as to carry out a reaction in the saponification reaction device; And / or, the lime milk preparation device further includes a calcium hydroxide particle size screening device.

4. The production device according to claim 1, characterized in that, The sedimentation concentration recycling device includes a sedimentation device, a concentration device, and a recycling device; And / or, the saponification residue acid addition device includes a feed end and a discharge end, wherein the feed end includes a saponification residue feed port and an acid feed port; further, the discharge end of the saponification residue acid addition device transports the product to a solid-liquid separation device, and after separation by the solid-liquid separation device, a clear liquid and solid waste residue are obtained.

5. The production device according to any one of claims 1 to 4, characterized in that, The production device further includes an industrial water treatment device, and the water inlet of the industrial water treatment device is connected to the liquid discharge end of the solid-liquid separation device and the second discharge end of the sedimentation concentration recycling device; And / or, the production device further includes a filter residue treatment device, and the feed end of the filter residue treatment device is connected to the solid material outlet of the solid-liquid separation device.

6. A production method of propylene oxide, characterized in that, The production method includes the following steps: Chloropropanol undergoes a saponification reaction in the system to obtain propylene oxide; The system includes lime milk, chlorohydrin liquid, concentrated liquid, and further reaction materials of the concentrated liquid and the chlorohydrin reaction product; The concentrated liquid is obtained by sedimentation and concentration of the saponification residue generated by the saponification reaction; Preferably, the production method is carried out in the production device according to any one of claims 1-5.

7. The production method according to claim 6, characterized in that, The sedimentation concentration ratio of the saponification residue is 1:1.05 to 1:8; And / or, the lime milk is a suspension obtained by mixing and reacting calcium hydroxide powder with water or concentrated liquid; And / or, the chlorohydrin liquid is a reaction liquid after a chlorohydrin reaction of the reaction product of propylene with chlorine and water; And / or, the saponification residue after sedimentation and concentration accounts for 70% to 99% of the total volume of the saponification residue, such as 75%, 80%, 85%, 90%, 92%, 95%; And / or, the ratio of the sum of the volumes of the concentrated solution for preparing lime milk, the concentrated solution further reacting with the chlorohydrin reaction product, and the concentrated solution returned to the system to the volume of the saponification residue after sedimentation and concentration is 1:2 to 1:

7.

8. The production method according to claim 6, characterized in that, Part of the saponification residue produced by the saponification reaction is acidified, and the pH value after acidification is 8.6 to 9.6; And / or, the flow rate ratio of the acidified saponification residue to the saponification residue separated by sedimentation is 1:3 to 1:8; And / or, the flow rate ratio of the concentrated solution to the chlorohydrin solution is 1:5 to 1:

20.

9. The production method according to any one of claims 6 - 8, characterized in that, The method for producing propylene oxide further includes: the acidified saponification residue is subjected to solid-liquid separation and sent to industrial water treatment and waste residue treatment; And / or, the method for producing propylene oxide further includes: other concentrated solutions except the concentrated solution for preparing lime milk, the concentrated solution further reacting with the chlorohydrin reaction product, and the concentrated solution returned to the system are sent for industrial water treatment.

10. The production method according to claim 6, characterized in that, The production method includes the following steps: (A1) Calcium hydroxide powder is mixed with water or a concentrated solution in the lime milk preparation device to obtain lime milk; (A2) Part of the saponification residue generated by the saponification reaction device enters the sedimentation and concentration recycling device to obtain a concentrated solution; part of the concentrated solution enters the lime milk preparation device, the further reaction device of the concentrated solution and the chlorohydrin reaction product, and the saponification reaction device; (A3) Another part of the saponification residue generated by the saponification reaction device enters the saponification residue acid addition device and the solid-liquid separation device, the separated liquid is sent to the industrial water treatment device, and the solid is sent to the waste residue treatment device; Or further includes step (A4) Another part of the concentrated solution of the sedimentation and concentration recycling device is sent to the industrial water treatment device.

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