A method and system for hydrolysis of spent ionic liquid catalysts

Abstract

The present application belongs to the field of green chemical technology, and particularly relates to a hydrolysis method and system of waste ionic liquid catalyst. The method comprises at least the following steps: 1) sending the waste ionic liquid into the hydrolyzer, rapidly mixing the waste ionic liquid with the circulating hydrolysis liquid sent by the cooler, and performing temperature control hydrolysis in the hydrolyzer; 2) discharging the hydrolysis liquid from the hydrolyzer into the oil-water separator to perform oil-water separation, and obtaining an aqueous phase; 3) boosting the pressure of the aqueous phase by the circulating pump, cooling the aqueous phase by the cooler, and finally circulating the aqueous phase back to the hydrolyzer. The technical scheme provided by the present application can effectively hydrolyze the waste ionic liquid catalyst, recycle the generated oil phase, control the water saving amount by low-temperature cooling and controlling the circulation water, control the maximum temperature of hydrolysis, ensure rapid hydrolysis, and realize no HCl gas generation.

Description

Technical Field

[0001] This invention belongs to the field of green chemical technology, specifically relating to a method and system for hydrolyzing waste ionic liquid catalysts. Background Technology

[0002] Ionic liquids are non-volatile, non-flammable, highly conductive, have high heat capacity, low vapor pressure, and stable properties. They also have good solubility for many inorganic salts and organic compounds, and are widely used in electrochemistry, organic synthesis, catalysis, separation and other fields. Compared with traditional organic solvents and electrolytes, ionic liquids have a series of outstanding advantages: 1) Wide liquid range, from below or near room temperature to above 300 degrees Celsius, with high thermal and chemical stability; 2) Very low vapor pressure, non-volatile, and do not evaporate during use or storage, allowing for recycling and eliminating the environmental pollution problems caused by volatile organic compounds; 3) High conductivity and a large electrochemical window, making them suitable as electrolytes for electrochemical research on many substances; 4) Their solubility in inorganic substances, water, organic substances, and polymers can be adjusted through the design of anions and cations, and their acidity can be adjusted to superacidity; 5) Highly tunable polarity, low viscosity, and high density, allowing them to form two-phase or multiphase systems, making them suitable as separation solvents or for constructing novel reaction-separation coupling systems; 6) Excellent solubility for a large number of inorganic and organic substances, and possessing the dual functions of solvent and catalyst, making them suitable as solvents or catalytically active carriers for many chemical reactions. These special properties and performance characteristics of ionic liquids have led to their widespread application in the fields of petrochemical refining and fine chemicals.

[0003] However, to maintain the catalytic activity of ionic liquids, the technology generates a certain amount of waste ionic liquid catalyst. This waste catalyst is corrosive and toxic, requiring treatment, which has become a bottleneck restricting the widespread adoption of ionic liquid technology. The series of patent applications filed by China University of Petroleum (Beijing), including 201810172037.0, 201810172039.X, and 201510982650.5, all involve converting the waste ionic liquid into general solid waste through digestion, neutralization, dehydration, and drying, but the emissions are high, failing to achieve resource utilization of the waste ionic liquid.

[0004] The main components of a type of waste ionic liquid are aluminum trichloride and quaternary ammonium salts. Only by effectively recovering and separating these two components can the ionic liquid be recycled, achieving the goals of environmental protection and cost reduction, thus demonstrating the true value of ionic liquids as catalysts. The removal of quaternary ammonium salts has become a bottleneck in the resource-based treatment of waste ionic liquids. Quaternary ammonium salts are characterized by non-evaporability, strong polarity, high water solubility, stable chemical properties, and poor biochemical properties, especially short-chain quaternary ammonium salts, which cannot be separated by conventional treatment and separation technologies. The paper "Determination of Quaternary Ammonium Salt Solubility and Its Application in the Recovery of Lewis Acid Waste Ionic Liquids" from Shandong University of Science and Technology utilizes steps such as hydrolysis, filtration, rotary evaporation, solution extraction, filtration, rotary evaporation, and drying to achieve the recycling of waste ionic liquids.

[0005] Hydrolysis of waste ionic liquids is a strongly exothermic reaction and a key aspect of ionic liquid recycling. In the reports above, the technical solution provided by China University of Petroleum (Beijing) uses a hydrolysis tank with built-in packing material for hydrolysis. This large tank and high hydrolysis temperature result in HCl precipitation. The paper from Shandong University of Science and Technology did not develop any hydrolysis technology.

[0006] This technology efficiently and rapidly mixes waste ionic liquid catalysts with water, incorporates internal heat extraction, eliminates HCl precipitation during hydrolysis, and requires minimal space, thus saving on investment. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method and system for hydrolyzing waste ionic liquid catalysts. The technical solution provided by this invention can effectively hydrolyze waste ionic liquid catalysts, reuse the resulting oil phase, control the maximum hydrolysis temperature by controlling low-temperature cooling and the amount of water saved through circulating water, ensuring rapid hydrolysis and achieving zero HCl gas generation.

[0008] The technical solution provided by this invention is as follows:

[0009] A hydrolysis system for a waste ionic liquid catalyst includes:

[0010] A hydrolyzer having a hydrolysate inlet, a hydrolysate outlet, and a waste ionic liquid inlet, and a water cooler is installed inside the hydrolyzer;

[0011] An oil-water separator connected to the hydrolysate outlet, the oil-water separator having an aqueous phase outlet and an oil phase outlet;

[0012] A circulation pump connected to the aqueous phase outlet;

[0013] And a cooler, which is connected to the circulation pump and the hydrolysate inlet.

[0014] Based on the above technical solution, by controlling the temperature inside the hydrolyzer, controlling the outlet temperature of the cooler, and controlling the mass ratio of the circulating hydrolysate entering the hydrolyzer to the waste ionic liquid entering the hydrolyzer, the waste ionic liquid catalyst can be fully and rapidly hydrolyzed and the quaternary ammonium salt can be decomposed in the hydrolyzer.

[0015] Furthermore, the waste ionic liquid inlet includes two inlets, located at one end near the hydrolysate inlet and one end near the hydrolysate outlet.

[0016] Based on the above technical solution, it is beneficial to achieve rapid and uniform mixing of circulating hydrolysate and waste ionic liquid.

[0017] Furthermore, each of the aforementioned inlets is equipped with a Venturi nozzle.

[0018] Based on the above technical solution, rapid mixing of waste ionic liquid and circulating hydrolysate can be ensured.

[0019] Furthermore, the hydrolysate inlet is also connected to a hydrolysate water replenishment pipeline.

[0020] The present invention also provides a method for hydrolyzing waste ionic liquid catalysts, using the above-described system to perform hydrolysis of waste ionic liquid catalysts.

[0021] Specifically, the hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0022] 1) The waste ionic liquid is fed into the hydrolyzer, where it is rapidly mixed with the circulating hydrolysate from the cooler, and temperature-controlled hydrolysis is carried out in the hydrolyzer.

[0023] 2) The hydrolysate discharged from the hydrolyzer enters the oil-water separator for oil-water separation to obtain the aqueous phase, while the upper oil phase can be recycled and processed in downstream facilities.

[0024] 3) The aqueous phase is pressurized by the circulating pump, cooled by the cooler, and finally circulated back to the hydrolyzer.

[0025] Furthermore, it also includes step 4): replenishing the hydrolyzer with fresh water through the hydrolyzed water replenishment pipeline; and discharging the liquid outlet of the cooler according to the liquid level of the oil-water separator, with the discharged hydrolysate being sent to downstream facilities for treatment.

[0026] Specifically, the temperature inside the hydrolyzer is 15–20°C.

[0027] Specifically: the outlet temperature of the cooler is less than or equal to 10°C.

[0028] Specifically, the mass ratio of the circulating hydrolysate entering the hydrolyzer to the waste ionic liquid entering the hydrolyzer is (40-70):1.

[0029] Based on the above conditions, the removal of quaternary ammonium salts can be ensured.

[0030] Specifically, the main components of the waste ionic liquid are aluminum trichloride and quaternary ammonium salt.

[0031] The beneficial effects of this invention are:

[0032] The technical solution of this invention can effectively hydrolyze waste chloroaluminate ionic liquid catalysts without generating HCl gas, and the system has a small footprint and saves investment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the hydrolysis system for the waste ionic liquid catalyst provided by the present invention.

[0034] Figure 2 This is a flowchart of a hydrolysis method for waste ionic liquid catalysts provided by the present invention.

[0035] Appendix Figure 1 The structures represented by each label are listed below:

[0036] 1. Hydrolyzer; 2. Oil-water separator; 3. Cooler; 4. Circulating pump. Detailed Implementation

[0037] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0038] Unless otherwise specified, the test methods used in the embodiments are conventional methods; unless otherwise specified, the materials and reagents used are commercially available.

[0039] The waste ionic liquid catalyst is taken from the alkylation process, and its quaternary ammonium salt content is about 200-800 mg / L.

[0040] Example 1

[0041] like Figure 1 As shown, the hydrolysis system for the waste ionic liquid catalyst includes: a hydrolyzer 1, an oil-water separator 2 connected to the outlet of the hydrolysate, a circulating pump 4 connected to the outlet of the aqueous phase, and a cooler 3.

[0042] The hydrolyzer 1 has a hydrolysate inlet, a hydrolysate outlet, and a waste ionic liquid inlet. Waste ionic liquid enters through the waste ionic liquid inlet.

[0043] The oil-water separator 2 has a water phase outlet and an oil phase outlet. The oil phase outlet can be connected to downstream facilities.

[0044] The cooler 3 is connected to the circulating pump 4 and to the hydrolysate inlet.

[0045] The hydrolyzer 1 may have a hydrolysis tank, and a water cooler is provided in the hydrolysis tank to rapidly and uniformly cool the hydrolysate.

[0046] Based on this technical solution, the temperature inside the hydrolyzer can be controlled, the outlet temperature of the cooler can be controlled, and the mass ratio of the circulating hydrolysate entering the hydrolyzer to the waste ionic liquid entering the hydrolyzer can be controlled.

[0047] Example 2

[0048] Based on Example 1, such as Figure 1 As shown, the hydrolysis system for the waste ionic liquid catalyst includes: a hydrolyzer 1, an oil-water separator 2 connected to the outlet of the hydrolysate, a circulating pump 4 connected to the aqueous phase outlet, and a cooler 3. The hydrolyzer 1 has a hydrolysate inlet, a hydrolysate outlet, and a waste ionic liquid inlet. The oil-water separator 2 has an aqueous phase outlet and an oil phase outlet. The cooler 3 is connected to the circulating pump 4 and the hydrolysate inlet. The waste ionic liquid inlet includes two inlets, one located near the hydrolysate inlet and the other near the hydrolysate outlet, each inlet equipped with a Venturi nozzle. Based on this technical solution, rapid mixing of the waste ionic liquid and the circulating hydrolysate can be achieved.

[0049] Example 3

[0050] Based on Example 2, such as Figure 1 As shown, the hydrolysis system for the waste ionic liquid catalyst includes: a hydrolyzer 1, an oil-water separator 2 connected to the hydrolysate outlet, a circulation pump 4 connected to the aqueous phase outlet, and a cooler 3. The hydrolyzer 1 has a hydrolysate inlet, a hydrolysate outlet, and a waste ionic liquid inlet. The oil-water separator 2 has an aqueous phase outlet and an oil phase outlet. The cooler 3 is connected to the circulation pump 4 and the hydrolysate inlet. The waste ionic liquid inlet includes two inlets, one located near the hydrolysate inlet and the other near the hydrolysate outlet, each inlet equipped with a Venturi nozzle. The hydrolysate inlet connects to the cooler 3 and the hydrolysate water replenishment pipeline.

[0051] Example 1

[0052] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0053] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0054] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0055] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0056] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolyzed water replenishment pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2, and the discharged hydrolyzed liquid can be sent to downstream facilities for treatment.

[0057] Waste ionic liquid enters the hydrolyzer in two streams. It is rapidly premixed with the circulating hydrolysate through a Venturi nozzle and then fully mixed and hydrolyzed. The hydrolyzer is cooled by a built-in water cooler. The hydrolyzed mixture enters the oil-water separator for oil-water separation. The oil can be discharged to downstream facilities for further treatment. The aqueous phase is pressurized by a circulating pump, cooled by a cooler, and then recycled back to the hydrolyzer. A fixed amount of hydrolysate is discharged to downstream facilities for further treatment.

[0058] After running for a period of time:

[0059] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0060] The outlet temperature of the cooler 3 is approximately 10°C;

[0061] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0062] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 45.8 mg / L.

[0063] The above process can be used as a reference. Figure 2 .

[0064] Example 2

[0065] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0066] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0067] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0068] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0069] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0070] After running for a period of time:

[0071] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0072] The outlet temperature of the cooler 3 is approximately 10°C;

[0073] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 40:1.

[0074] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 73.6 mg / L.

[0075] Example 3

[0076] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0077] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0078] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0079] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0080] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0081] After running for a period of time:

[0082] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0083] The outlet temperature of the cooler 3 is approximately 10°C;

[0084] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 70:1.

[0085] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 59.9 mg / L.

[0086] Example of effect 4

[0087] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0088] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0089] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0090] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0091] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0092] After running for a period of time:

[0093] The temperature inside the hydrolyzer 1 is approximately 15°C.

[0094] The outlet temperature of the cooler 3 is approximately 10°C;

[0095] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0096] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 55.4 mg / L.

[0097] Example 5

[0098] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0099] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0100] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0101] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0102] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0103] After running for a period of time:

[0104] The temperature inside the hydrolyzer 1 is approximately 20°C.

[0105] The outlet temperature of the cooler 3 is approximately 10°C;

[0106] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0107] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 78.4 mg / L.

[0108] Comparative Example 1

[0109] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0110] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0111] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0112] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0113] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0114] After running for a period of time:

[0115] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0116] The outlet temperature of the cooler 3 is approximately 10°C;

[0117] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 20:1.

[0118] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 189.5 mg / L.

[0119] Comparative Example 2

[0120] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0121] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0122] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0123] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0124] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0125] After running for a period of time:

[0126] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0127] The outlet temperature of the cooler 3 is approximately 10°C;

[0128] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 90:1.

[0129] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 83.6 mg / L.

[0130] Comparative Example 3

[0131] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0132] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0133] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0134] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0135] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0136] After running for a period of time:

[0137] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0138] The outlet temperature of the cooler 3 is approximately 15°C;

[0139] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0140] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 89.6 mg / L.

[0141] Comparative Example 4

[0142] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0143] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0144] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0145] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0146] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0147] After running for a period of time:

[0148] The temperature inside the hydrolyzer 1 is approximately 10°C.

[0149] The outlet temperature of the cooler 3 is approximately 10°C;

[0150] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0151] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 91.8 mg / L.

[0152] Comparative Example 5

[0153] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0154] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0155] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0156] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0157] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0158] After running for a period of time:

[0159] The temperature inside the hydrolyzer 1 is approximately 20°C.

[0160] The outlet temperature of the cooler 3 is approximately 10°C;

[0161] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0162] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 80.2 mg / L.

[0163] Comparative Example 6

[0164] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0165] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0166] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0167] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0168] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0169] After running for a period of time:

[0170] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0171] The outlet temperature of the cooler 3 is approximately 10°C;

[0172] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0173] The difference is that both venturi nozzles are replaced with ordinary straight pipes.

[0174] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 221.5 mg / L.

[0175] Comparative Example 7

[0176] The hydrolysis method for waste ionic liquid catalysts includes the following steps:

[0177] 1) The waste ionic liquid is fed into the hydrolyzer 1, and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent from the cooler 3, and temperature-controlled hydrolysis is carried out in the hydrolyzer 1.

[0178] 2) The hydrolysate discharged from the hydrolyzer 1 enters the oil-water separator 2 for oil-water separation to obtain an aqueous phase;

[0179] 3) The aqueous phase is pressurized by the circulating pump 4, cooled by the cooler 3, and finally circulated back to the hydrolyzer 1;

[0180] 4) Fresh water is supplied to the hydrolyzer 1 through the hydrolysis water supply pipeline; the liquid outlet of the cooler 3 is discharged according to the liquid level of the oil-water separator 2.

[0181] After running for a period of time:

[0182] The temperature inside the hydrolyzer 1 is approximately 17.5°C;

[0183] The outlet temperature of the cooler 3 is approximately 10°C;

[0184] The mass ratio of the circulating hydrolysate entering the hydrolyzer 1 to the waste ionic liquid entering the hydrolyzer 1 is controlled to reach 55:1.

[0185] The difference is that the number of waste ion liquid inlets is reduced to one, and it is located in the middle of hydrolyzer 1.

[0186] The liquid outlet of cooler 3 was then sampled and tested: the quaternary ammonium salt content was 153.1 mg / L.

[0187] The comparisons show that changes in each parameter lead to a decrease in the effectiveness of quaternary ammonium salt treatment.

[0188] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydrolysis system for a waste ionic liquid catalyst, characterized in that, include: Hydrolyzer (1), the hydrolyzer (1) has a hydrolysate inlet, a hydrolysate outlet and a waste ionic liquid inlet, and a water cooler is provided inside the hydrolyzer (1); An oil-water separator (2) connected to the outlet of the hydrolysate has an aqueous phase outlet and an oil phase outlet; A circulation pump (4) connected to the outlet of the aqueous phase; And a cooler (3), which is connected to the circulating pump (4) and the hydrolysate inlet.

2. The hydrolysis system for waste ionic liquid catalysts according to claim 1, characterized in that: The waste ionic liquid inlet includes two inlets, one located near the hydrolysate inlet and the other near the hydrolysate outlet.

3. The hydrolysis system for waste ionic liquid catalysts according to claim 2, characterized in that: Each of the aforementioned inlets is equipped with a Venturi nozzle.

4. The hydrolysis system for waste ionic liquid catalysts according to claim 3, characterized in that: The hydrolysate inlet is also connected to a hydrolysate water replenishment pipeline.

5. A method for hydrolyzing waste ionic liquid catalysts, characterized in that: The system described in claim 4 is used to perform hydrolysis of waste ionic liquid catalysts.

6. The method for hydrolyzing waste ionic liquid catalyst according to claim 5, characterized in that, At least the following steps are included: 1) The waste ionic liquid is fed into the hydrolyzer (1), and the waste ionic liquid is rapidly mixed with the circulating hydrolysate sent out by the cooler (3) and temperature-controlled hydrolysis is carried out in the hydrolyzer (1); 2) The hydrolysate discharged from the hydrolyzer (1) enters the oil-water separator (2) for oil-water separation to obtain an aqueous phase; 3) The aqueous phase is pressurized by the circulating pump (4), cooled by the cooler (3), and finally circulated back to the hydrolyzer (1).

7. The method for hydrolyzing waste ionic liquid catalyst according to claim 6, characterized in that, It also includes step 4): replenishing fresh water to the hydrolyzer (1) through the hydrolyzed water replenishment pipeline; and discharging the liquid outlet of the cooler (3) according to the liquid level of the oil-water separator (2).

8. The method for hydrolyzing waste ionic liquid catalyst according to claim 7, characterized in that: The temperature inside the hydrolyzer (1) is 15-20℃.

9. The method for hydrolyzing waste ionic liquid catalysts according to claim 7, characterized in that: The outlet temperature of the cooler (3) is less than or equal to 10°C.

10. The method for hydrolyzing waste ionic liquid catalyst according to claim 7, characterized in that: The mass ratio of the circulating hydrolysate entering the hydrolyzer (1) to the waste ionic liquid entering the hydrolyzer (1) is (40-70):1.

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