TDI tar solid residue resource utilization method

Abstract

The invention provides a TDI (toluene diisocynate) tar solid residue resource utilization method which comprises the following steps: (1) crushing and screening TDI tar solid residues to obtain tar fine particles; (2) fully mixing the tar fine particles obtained in the step (1) with an inactivating agent, and standing for reaction to obtain inactivated tar; (3) mixing the inactivated tar obtained in the step (2) with coal and water to obtain a coal water slurry solution; and (4) spraying the coal water slurry solution obtained in the step (3) and pure oxygen into a gasification furnace through a burner, and carrying out gasification reaction to obtain H2 and CO from an outlet material of the gasification furnace. According to the method, harmful substances such as nitric oxide and dioxin do not exist at an outlet of the gasification furnace, harmless treatment can be achieved on components in the TDI tar solid residues, and benefit increment can be achieved through the heat value of the TDI tar solid residues.

Description

Technical Field

[0001] The invention relates to a method for harmlessly treating and resourcefully utilizing TDI tar solid residue, which can not only achieve harmless treatment of components therein, but also realize benefit appreciation by utilizing the calorific value thereof. Background Art

[0002] Toluene diisocyanate (TDI) is widely used in the fields of sponges, polyurethanes, coatings and curing agents. The current industrial production process of TDI is mainly based on phosgenation, and the main raw materials are toluenediamine (TDA for short) and phosgene. Since TDA still has side reactions during the phosgenation reaction and the subsequent TDI distillation and purification process, tar residues mainly composed of ureas, biuret and carbodiimide are generated. In order to increase the yield of TDI, it is necessary to perform secondary drying on the heavy component tar containing TDI to recover all TDI monomers, and finally obtain tar residues in solid form.

[0003] In the early days, the main treatment methods for TDI tar residues were: dumping into the sea, burying and incineration. Dumping into the sea and burying will pollute water and soil, and incineration will produce harmful substances such as nitrogen oxides and dioxins, which do not meet the environmental protection requirements of carbon emission reduction. In order to realize the resource utilization of tar, there are currently existing literatures introducing methods for treating tar residues.

[0004] Patent CN110000193A discloses a method for treating TDI tar residue, in which the tar residue and a polar solvent are placed in a high-temperature and high-pressure reactor for digestion reaction to obtain a digestion filtrate and a solid residue, wherein the filtrate is distilled to obtain an aniline mixed product, the residue is not treated, and the tar treatment efficiency is low.

[0005] Patent CN109913255A discloses a method for preparing liquid fuel using TDI tar residue. The processing method is similar to that of patent CN110000193A, except that a mixed combustion accelerator is added to the digestion filtrate as liquid fuel, and the residue is still not processed.

[0006] Patent CN113929097A discloses a method and application of preparing porous materials using TDI solid tar residues, wherein the tar residues are crushed and pre-carbonized, and then mixed with an activator to obtain TDI tar porous materials. This material is used in the adsorption of organic amine wastewater, but its application range is relatively narrow, and the treatment of the material after adsorption still needs to be solved.

[0007] In summary, since TDI tar solid residue is formed by the polymerization of organic TDI, it has the characteristics of high calorific value, no ash, and easy spontaneous combustion. Direct incineration will produce harmful substances such as nitrogen oxides and dioxins. It is necessary to find a suitable treatment measure that can not only render the components harmless, but also utilize its calorific value to achieve value-added benefits. Summary of the invention

[0008] In view of the above problems, the present invention provides a method for resource utilization of TDI tar solid residue, which can convert TDI tar into H 2 , CO and other gases are used to synthesize chemical raw materials such as methanol and urea. No harmful substances such as nitrogen oxides and dioxins are produced, and no solid residue is left, thus achieving harmless treatment.

[0009] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0010] A method for resource utilization of TDI tar solid residue, comprising the following steps:

[0011] (1) crushing and screening the TDI tar solid residue to obtain tar fine particles;

[0012] (2) fully mixing the tar fine particles obtained in step (1) with an inactivator, and allowing the mixture to react to obtain inactivated tar;

[0013] (3) mixing the deactivated tar obtained in step (2) with coal and water to obtain a water-coal slurry solution;

[0014] (4) injecting the water-coal slurry solution obtained in step (3) and pure oxygen into a gasifier through a burner for gasification reaction, and obtaining H from the material at the outlet of the gasifier. 2 、CO。

[0015] In the present invention, the TDI tar solid residue in step (1) is a solid residue obtained by high-temperature drying of TDI heavy component tar at 250-300°C, such as 250°C, 270°C, 290°C, and 300°C. In the process of producing TDI by phosgenation, the raw material toluenediamine (TDA) will undergo side reactions during the phosgenation reaction and the subsequent TDI distillation and purification process to generate heavy component tar containing TDI (including ureas, biuret, carbodiimide, etc.). In order to increase the yield of TDI, it is necessary to perform high-temperature drying treatment on the heavy component tar to recover TDI, thereby obtaining TDI tar solid residue.

[0016] In the present invention, the crushing and screening in step (1) has a particle size of 150-2000 μm, for example 150 μm, 300 μm, 500 μm, 750 μm, 1000 μm, 1250 μm, 1500 μm, 1750 μm, 2000 μm, preferably 300-1000 μm.

[0017] In the present invention, the inactivator in step (2) is a combination of hexadecyltrimethylammonium bromide and one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine;

[0018] Preferably, the inactivator is a combination of an aqueous solution of hexadecyltrimethylammonium bromide and one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine;

[0019] More preferably, the inactivator is an aqueous solution of hexadecyltrimethylammonium bromide, mixed with one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine in a mass ratio of 1:4-10, such as 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, and the mixing temperature is preferably 20-40°C, such as 20°C, 30°C, 40°C;

[0020] More preferably, the concentration of the aqueous solution of hexadecyltrimethylammonium bromide is 50-100 mg / L, for example 50 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, 100 mg / L.

[0021] In the present invention, the mixing mass ratio of the inactivator and the tar fine particles in step (2) is 0.01-1:1, for example, 0.01:1, 0.05:1, 0.1:1, 0.3:1, 0.5:1, 0.7:1, 1:1, preferably 0.1-0.3:1.

[0022] In the present invention, the static reaction in step (2) has no requirement on the temperature, and room temperature is sufficient. The reaction time is 1-2 h, for example, 1 h, 1.3 h, 1.5 h, 1.7 h, and 2 h.

[0023] In the present invention, the solid content of the coal-water slurry solution in step (3) is 58-67wt%, such as 58wt%, 60wt%, 62wt%, 64wt%, 67wt%, preferably 60-64wt%; the amount of water added is controlled by the solid content;

[0024] The viscosity of the coal water slurry solution is 400-1200 mPa·s, for example, 400 mPa·s, 600 mPa·s, 800 mPa·s, 1000 mPa·s, 1200 mPa·s, preferably 500-900 mPa·s.

[0025] In the present invention, the mass ratio of the deactivated tar and coal mixed in step (3) is 1:25-100, for example 1:25, 1:40, 1:60, 1:80, 1:100, and the type of coal is not limited, such as bituminous coal.

[0026] In the present invention, the flow rate ratio of the pure oxygen and the water-coal slurry solution injected into the gasifier in step (4) is 440-580 (Nm 3 / m 3 ), for example 440(Nm 3 / m 3 )、450(Nm 3 / m 3 )、470(Nm 3 / m 3 )、490(Nm 3 / m 3 )、510(Nm 3 / m 3 )、530(Nm 3 / m 3 )、550(Nm 3 / m 3 )、580(Nm 3 / m 3 ), preferably 460-480 (Nm 3 / m 3 );

[0027] Preferably, the airspeed is 1000-1400h -1 , for example 1000h -1 , 1100h -1 , 1200h -1 、1300h -1 , 1400h -1 , based on oxygen;

[0028] Preferably, the gasifier is a pulverized coal gasifier, and more preferably, the gasifier is of a single-nozzle or multi-nozzle type.

[0029] In the present invention, when the gasification reaction is carried out in the gasifier in step (4), the operating pressure is 4-8MpaG, for example, 4MpaG, 5MpaG, 6MpaG, 7MpaG, 8MpaG, and the operating temperature is 1100-1400°C, for example, 1100°C, 1200°C, 1300°C, 1400°C.

[0030] In the present invention, the outlet material of the gasifier in step (4) includes gas phase, water phase and waste residue, wherein the gas phase mainly includes H 2 , CO, and a small amount of CO 2 , CH 4 、N 2 , which does not contain harmful substances such as nitrogen oxides and dioxins, and realizes the harmless treatment of TDI tar.

[0031] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0032] The invention uses a mixture of cetyltrimethylammonium bromide and one or more of dimethyldiethanolamine, 2-hydroxyethylamine and triisopropanolamine to inactivate TDI tar solid residue, so that active components in the tar are converted into inert components, self-polymerization and heat release are avoided, and urea substances with relatively high viscosity are formed, which are then mixed with coal and water to form a water-coal slurry solution to prepare synthesis gas.

[0033] The treatment method of the present invention can be used to treat TDI tar solid residue harmlessly, not only without solid residue, but also to produce CO and H needed for manufacturing chemical materials. 2 And other raw gases, realizing the maximum value. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with embodiments. The embodiments of the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0035] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were purchased from commercially available products.

[0036] Source of TDI tar solid residue: The heavy component tar containing TDI is generated in the process of producing TDI by phosgenation, and the solid residue is obtained by high-temperature drying at 250-300℃.

[0037] Example 1

[0038] The method for resource utilization of TDI tar solid residue comprises the following steps:

[0039] Take 50 g of 100 mg / L hexadecyltrimethylammonium bromide (CTAB) aqueous solution into a 1 L beaker, add 500 g of dimethyldiethanolamine (AR, Sinopharm), set the stirring rate to 500 rpm, and stir at 30° C. for 30 min to obtain the inactivator.

[0040] (1) 1 kg of TDI tar solid residue was crushed and sieved to obtain tar fine particles with a particle size of 500-1000 μm.

[0041] (2) 100 g of the inactivator was fully mixed with 1 kg of tar fine particles so that the inactivator was coated on the surface of the tar fine particles, and the mixture was allowed to react for 1 hour to obtain inactivated tar.

[0042] (3) 500 g of deactivated tar was mixed with 25 kg of raw coal, 10.75 kg of water was added, and the mixture was mixed and ground in a mill to obtain a water-coal slurry solution.

[0043] The fluidity of coal slurry was tested according to the standard method of GB- / T 18855-2008. The apparent viscosity of the slurry at 25°C was measured using a viscometer, and the concentration of the coal slurry (solid content) was measured using a rapid moisture meter. The results are shown in Table 1.

[0044] (4) Pure oxygen and water-coal slurry solution were mixed and sprayed into the entrained flow reactor, with an oxygen-coal ratio of 480 (Nm 3 / m 3 ), airspeed is 1200h -1 , gasification reaction was carried out, the reaction temperature was 1200℃, the reaction pressure was 6MPaG, and the gas phase analysis of the gasifier outlet material was CO, H 2 The results are shown in Table 1.

[0045] Example 2

[0046] The method for resource utilization of TDI tar solid residue comprises the following steps:

[0047] Take 50 g of 100 mg / L CTAB aqueous solution into a 1 L beaker, add 300 g of 2-hydroxyethylamine (AR, Sinopharm), set the stirring rate to 500 rpm, and stir at 30° C. for 30 min to obtain the inactivator.

[0048] (1) 1 kg of TDI tar solid residue was crushed and sieved to obtain tar fine particles with a particle size of 500-1000 μm.

[0049] (2) 300 g of the inactivator was fully mixed with 1 kg of tar fine particles so that the inactivator was coated on the surface of the tar fine particles. The mixture was allowed to react for 1.5 h to obtain inactivated tar.

[0050] 500 g of deactivated tar was mixed with 25 kg of raw coal, 10.75 kg of water was added, and the mixture was mixed and ground in a mill to obtain a coal slurry solution.

[0051] The fluidity of coal slurry was tested according to the standard method of GB- / T 18855-2008. The apparent viscosity of the slurry at 25°C was measured using a viscometer, and the concentration of the coal slurry was measured using a rapid moisture meter. The results are shown in Table 1.

[0052] (4) Pure oxygen and water-coal slurry solution were mixed and sprayed into the entrained flow reactor, with an oxygen-coal ratio of 560 (Nm 3 / m 3 ), airspeed is 1000h -1 , gasification reaction was carried out, the reaction temperature was 1200℃, the reaction pressure was 6MPaG, and the gas phase analysis of the gasifier outlet material was CO, H 2 The results are shown in Table 1.

[0053] Example 3

[0054] The method for resource utilization of TDI tar solid residue comprises the following steps:

[0055] Take 50 g of 100 mg / L CTAB aqueous solution into a 1 L beaker, add 400 g of triisopropanolamine (AR, Sinopharm), set the stirring rate to 500 rpm, and stir at 30° C. for 30 min to obtain an inactivator.

[0056] (1) 1 kg of TDI tar solid residue was crushed and sieved to obtain tar fine particles with a particle size of 500-1000 μm.

[0057] (2) 100 g of the inactivator was fully mixed with 1 kg of tar fine particles so that the inactivator was coated on the surface of the tar fine particles, and the mixture was allowed to react for 1 hour to obtain inactivated tar.

[0058] (3) 500 g of deactivated tar was mixed with 50 kg of raw coal, 21.17 kg of water was added, and the mixture was mixed and ground in a mill to obtain a water-coal slurry solution.

[0059] The fluidity of coal slurry was tested according to the standard method of GB- / T 18855-2008. The apparent viscosity of the slurry at 25°C was measured using a viscometer, and the concentration of the coal slurry was measured using a rapid moisture meter. The results are shown in Table 1.

[0060] (4) Pure oxygen and water-coal slurry solution were mixed and sprayed into the entrained flow reactor, with an oxygen-coal ratio of 580 (Nm 3 / m 3 ), airspeed is 1000h -1 , gasification reaction was carried out, the reaction temperature was 1200℃, the reaction pressure was 6MPaG, and the gas phase analysis of the gasifier outlet material was CO, H 2 The results are shown in Table 1.

[0061] Example 4

[0062] The method for resource utilization of TDI tar solid residue comprises the following steps:

[0063] Take 50 g of 100 mg / L CTAB aqueous solution into a 1 L beaker, add 200 g of dimethyldiethanolamine (AR, Sinopharm), set the stirring rate to 500 rpm, and stir at 30° C. for 30 min to obtain the inactivator.

[0064] (1) 1 kg of TDI tar solid residue was crushed and sieved to obtain tar fine particles with a particle size of 500-1000 μm.

[0065] (2) 100 g of the inactivator was fully mixed with 1 kg of tar fine particles so that the inactivator was coated on the surface of the tar fine particles, and the mixture was allowed to react for 2 h to obtain inactivated tar.

[0066] (3) 500 g of deactivated tar was mixed with 12.5 kg of raw coal, 5.54 kg of water was added, and the mixture was mixed and ground in a mill to obtain a water-coal slurry solution.

[0067] The fluidity of coal slurry was tested according to the standard method of GB- / T 18855-2008. The apparent viscosity of the slurry at 25°C was measured using a viscometer, and the concentration of the coal slurry was measured using a rapid moisture meter. The results are shown in Table 1.

[0068] (4) Pure oxygen and water-coal slurry solution were mixed and sprayed into the entrained flow reactor, with an oxygen-coal ratio of 580 (Nm 3 / m 3 ), airspeed is 1200h -1 , gasification reaction was carried out, the reaction temperature was 1200℃, the reaction pressure was 6MPaG, and the gas phase analysis of the gasifier outlet material was CO, H 2 The results are shown in Table 1.

[0069] Comparative Example 1

[0070] Referring to Example 1, except that steps 1) and 2) are omitted, i.e., no deactivated tar is added in step 3), 25 kg of raw coal is mixed and ground with 10.42 kg of water in a mill to obtain a water-coal slurry solution, and a gasification reaction is carried out under the same conditions as step (4). The results are shown in Table 1.

[0071] Comparative Example 2

[0072] Referring to Example 1, the difference is that step 2) is omitted, the fine tar particles of step 1) are directly used in step 3) to obtain a water-coal slurry solution, and the gasification reaction is carried out under the same conditions as step (4). The results are shown in Table 1.

[0073] Comparative Example 3

[0074] Referring to Example 1, the difference is that in step 2), only 100 g of 100 mg / L cetyltrimethylammonium bromide (CTAB) aqueous solution is used as the inactivator to obtain a water-coal slurry solution, and the gasification reaction is carried out under the same conditions as step (4). The results are shown in Table 1.

[0075] Comparative Example 4

[0076] Referring to Example 1, the difference is that in step 2), only 100 g of a 500 mg / L dimethyldiethanolamine aqueous solution is used as the inactivator to obtain a water-coal slurry solution D4, and a gasification reaction is carried out under the same conditions as step (4). The results are shown in Table 1.

[0077] Comparative Example 5

[0078] Referring to Example 1, the difference is that in step 2), only cetyltrimethylammonium bromide (CTAB) is replaced by ammonium sulfate in the deactivator, and the other conditions remain unchanged to obtain a water-coal slurry solution, and a gasification reaction is carried out under the same conditions as step (4). The results are shown in Table 1.

[0079] Table 1 Slurrying performance and gasification reaction evaluation results of Examples 1-4 and Comparative Examples 1-5 Coal-water slurry

[0080]

[0081] Among them, the flow properties of water-coal slurry are A>B>C>D. The fluidity below B does not meet the normal flow requirements of the coal slurry and cannot be smoothly delivered into the reactor.

[0082] As can be seen from the above table, the TDI solid tar residue is inactivated by the method of the present invention, so that the active components in the tar are converted into inert components, and the prepared water-coal slurry has stable performance. The water-coal slurry and pure oxygen are injected into the gasifier through the burner to produce CO, H 2 It can produce effective gases without producing harmful substances such as nitrogen oxides and dioxins. It can not only render the components in TDI tar solid residue harmless, but also realize benefit appreciation by utilizing its calorific value.

Claims

1. A method for resource utilization of TDI tar solid residue, It is characterized in that the steps include: (1) crushing and screening the TDI tar solid residue to obtain tar fine particles; (2) fully mixing the tar fine particles obtained in step (1) with an inactivator, and allowing the mixture to react to obtain inactivated tar; (3) mixing the deactivated tar obtained in step (2) with coal and water to obtain a water-coal slurry solution; (4) injecting the water-coal slurry solution obtained in step (3) and pure oxygen into a gasifier through a burner for gasification reaction, and obtaining H from the material at the outlet of the gasifier. 2 、CO。 2. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The crushing and screening in step (1) has a particle size of 150-2000 μm, preferably 300-1000 μm.

3. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The inactivator in step (2) is a composition of hexadecyltrimethylammonium bromide and one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine.

4. The method for resource utilization of TDI tar solid residue according to claim 3, It is characterized in that The inactivator is a combination of an aqueous solution of hexadecyltrimethylammonium bromide and one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine; Preferably, the inactivator is a composition obtained by mixing an aqueous solution of hexadecyltrimethylammonium bromide with one or more selected from dimethyldiethanolamine, 2-hydroxyethylamine, and triisopropanolamine in a mass ratio of 1:4-10, and the mixing temperature is preferably 20-40°C; Preferably, the aqueous solution concentration of hexadecyltrimethylammonium bromide is 50-100 mg / L.

5. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The mixing mass ratio of the inactivator to the tar fine particles in step (2) is 0.01-1:1, preferably 0.1-0.3:

1.

6. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The step (2) is allowed to stand for reaction, and the reaction time is 1-2 hours.

7. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The solid content of the coal-water slurry solution in step (3) is 58-67 wt %, preferably 60-64 wt %; and / or The viscosity of the coal water slurry solution in step (3) is 400-1200 mPa·s, preferably 500-900 mPa·s.

8. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The mass ratio of the deactivated tar and coal mixed in step (3) is 1:25-100.

9. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The flow rate ratio of the pure oxygen and the water-coal slurry solution injected into the gasifier in step (4) is 440-580 (Nm 3 / m 3 ), preferably 460-480 (Nm 3 / m 3 ); Preferably, the airspeed is 1000-1400h -1 , based on oxygen; Preferably, the gasifier is a pulverized coal gasifier, and more preferably, the gasifier is of a single-nozzle or multi-nozzle type.

10. The method for resource utilization of TDI tar solid residue according to claim 1, It is characterized in that The gasification reaction in step (4) has a pressure of 4-8 MpaG and a temperature of 1100-1400°C.

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