A cracking process for the heavy components of butanol and octanol residue

Abstract

The present invention relates to a cracking process for the heavy components of butanol and octanol residues. The heavy components of butanol and octanol residues are introduced into a reactive distillation column system for cracking reactions. The reactive distillation column system includes a reactive distillation column, a reboiler, a cooler, a reflux drum, and a reflux pump. The reactive distillation column includes a rectifying section, a stripping section, and a reaction section, which are arranged successively from top to bottom. The reaction section is filled with a catalyst for catalyzing the cracking of the heavy components of butanol and octanol residues. The heavy components of butanol and octanol residues enter from the inlet between the rectifying section and the stripping section, and cracking reactions occur when flowing through the reaction section. After the reaction, the material is heated by the reboiler to generate gaseous light components. The gaseous light components rise to the top of the column, are discharged from the top outlet, and are condensed by the cooler to obtain liquid light components. After the liquid light components flow through the reflux drum and the reflux pump successively, a part of them refluxes into the reactive distillation column from the inlet above the rectifying section, and the other part is output from the reactive distillation column system.

Description

Technical Field

[0001] The invention belongs to the technical field of butanol raffinate recovery, and in particular relates to a cracking process for heavy components of butanol raffinate. Background Art

[0002] The main production process of butyl octanol is carbonyl synthesis, which inevitably produces butyl octanol residue accounting for 6% to 10% of the total mass of the product. The components of butyl octanol residue are complex, and contain a large number of valuable components. If it is discharged directly, it will not only cause waste of resources but also pollute the environment. In the past, it was mostly used as fuel. Now, in order to improve the economic benefits of butyl octanol residue, various production enterprises use the different boiling points of the components in the butyl octanol residue to separate and recover the C4 to C8 light components in the residue by multi-tower distillation. The remaining heavy components account for about 40% of the total amount of butyl octanol residue, and contain more aldehyde condensation products (including acetal, cyclic acetal, etc.) and long carbon chain esters, which are difficult to handle.

[0003] The heavy component of the butanol raffinate can be obtained by cracking C4 and C8 and other light components with utilization value, and then returns to the fractionation unit for recovery and separation, further improving the economic benefit of the butanol raffinate. The cracking of the existing butanol raffinate heavy component mainly includes thermal cracking reaction and catalyst catalytic reaction, the former has high energy consumption and can produce a large amount of waste water, and the latter is more favored because it is easy to separate, regenerative and does not produce waste water substantially. However, due to the poor stability of the catalyst for catalyzing the reorganization and cracking of the butanol raffinate, it is not suitable for the long-term continuous catalytic cracking reaction of the butanol raffinate heavy component, which causes poor effect when large-scale treatment of the butanol raffinate heavy component. Summary of the invention

[0004] The invention aims to provide a cracking process for the heavy components of the butanol residue, which can realize large-scale continuous cracking treatment of the heavy components of the butanol residue, significantly reduce the cost of the recombinant cracking of the butanol residue, and improve the economic benefits of the heavy components of the butanol residue.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a cracking process for the heavy components of butanol and octanol residues. The heavy components of butanol and octanol residues are introduced into a reactive distillation column system for cracking reaction. The reactive distillation column system includes a reactive distillation column, a reboiler, a cooler, a reflux drum, and a reflux pump. The reactive distillation column includes a rectifying section, a stripping section, and a reaction section arranged in sequence from top to bottom. The reaction section is filled with a catalyst for catalyzing the cracking of the heavy components of butanol and octanol residues. The heavy components of butanol and octanol residues enter from the inlet between the rectifying section and the stripping section, and cracking reaction occurs when flowing through the reaction section. After the reaction, the material is heated by the reboiler to generate gaseous light components. The gaseous light components enter the reactive distillation column from the inlet between the stripping section and the reaction section and rise to the top of the column, are discharged from the top outlet, and are condensed by the cooler to obtain liquid light components. After the liquid light components flow through the reflux drum and the reflux pump in sequence, a part of them refluxes into the reactive distillation column from the inlet above the rectifying section, and the other part is output from the reactive distillation column system.

[0007] In an embodiment of the present invention, the top temperature of the reactive distillation column is 170 - 250 °C, the temperature of the reaction section is 190 - 300 °C, and the top temperature of the reactive distillation column is less than the temperature of the reaction section. In the embodiment of the present invention, it is basically unnecessary to additionally control the temperature of the stripping section, and a thermometer can be set for monitoring.

[0008] In an embodiment of the present invention, the heating temperature of the reboiler is 280 - 300 °C.

[0009] Further, the top temperature of the reactive distillation column is 170 - 210 °C, and the temperature of the reaction section is 250 - 280 °C.

[0010] In an embodiment of the present invention, the pressure inside the reactive distillation column is 0.5 - 1.5 Mpa, such as 0.5 Mpa, 0.6 Mpa, 0.7 Mpa, 0.8 Mpa, 0.9 Mpa, 1.0 Mpa, 1.1 Mpa, 1.2 Mpa, 1.3 Mpa, 1.4 Mpa, 1.5 Mpa.

[0011] In an embodiment of the present invention, the inside of the reactive distillation column is an inert gas atmosphere.

[0012] Further, the inert gas is nitrogen.

[0013] In an embodiment of the present invention, the feed flow rate of the heavy components of butanol and octanol residues is 1 - 2 t / h.

[0014] In an embodiment of the present invention, the residence time in the reaction section is 0.5 - 1 h.

[0015] In an embodiment of the present invention, the number of effective trays in the rectifying section is 25 - 32.

[0016] In the embodiment of the present invention, the number of effective trays in the stripping section is 1 to 5 trays.

[0017] In the embodiment of the present invention, the reflux ratio of the reflux is 1 to 5, such as 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5.

[0018] In the embodiment of the present invention, the catalyst includes a catalyst carrier, a catalyst active center loaded on the catalyst carrier, and a promoter.

[0019] Specifically, the catalyst active center is titanium oxide.

[0020] Specifically, the promoter is one or more of iron, cobalt, nickel, manganese, copper, molybdenum, tungsten, tin and their oxides.

[0021] Specifically, the catalyst carrier is one or more of alumina, silica, magnesium aluminum hydrotalcite, hydroxyapatite, Y-type molecular sieve, A-type molecular sieve, ZSM-5, Beta-molecular sieve, coconut shell charcoal, XC-72R, XC-72.

[0022] Specifically, the mass of the titanium oxide is 1% to 45% of the total mass of the catalyst, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%.

[0023] Specifically, the mass of the promoter is 0.01% to 8% of the total mass of the catalyst, such as 0.01%, 0.05%, 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%.

[0024] Specifically, the specific surface area of the catalyst is 95 to 120 m 2 / g, and further preferably 95 to 110 m 2 / g, and still further preferably 95 to 105 m 2 / g.

[0025] Further, the mass of the titanium oxide is 8% to 25% of the total mass of the catalyst.

[0026] Furthermore, the mass of the titanium oxide is 10% - 20% of the total mass of the catalyst.

[0027] Further, the mass of the promoter is 0.5% - 5% of the total mass of the catalyst.

[0028] Furthermore, the mass of the promoter is 2% - 5% of the total mass of the catalyst.

[0029] Further, the catalyst carrier is activated alumina pellets and / or activated silica pellets.

[0030] Further, the particle size of the catalyst carrier is 0.3 - 3 mm.

[0031] According to some specific embodiments of the present invention, the catalyst carrier is activated alumina pellets with a particle size of 0.3 - 3 mm or activated silica pellets with a particle size of 0.3 - 3 mm.

[0032] Further, the promoter is one or more of iron oxide, nickel oxide, or copper oxide.

[0033] According to some specific embodiments of the present invention, the promoter is iron oxide or the promoter is nickel oxide and copper oxide.

[0034] The present invention also provides a preparation method of the above catalyst for catalytic recombination and cracking of butanol and octanol residues, and the preparation method includes the following steps:

[0035] (1) Impregnate the catalyst carrier with a promoter precursor solution, dry it, and calcine it at 400 - 500 °C to obtain a carrier material loaded with the promoter;

[0036] (2) Mix the catalyst active center precursor with a first solvent and then impregnate the carrier material loaded with the promoter, and dry to obtain a catalyst precursor;

[0037] (3) Heat-treat the catalyst precursor in a second solvent at 80 - 250 °C, wash it with water, and dry to obtain a catalyst intermediate;

[0038] (4) Calcinate the catalyst intermediate at 150 - 500 °C to obtain the catalyst,

[0039] wherein, the catalyst active center precursor is one or more of isopropyl titanate, tetrabutyl titanate, or titanium tetrachloride,

[0040] The promoter precursor is one or more of iron nitrate, iron acetate, iron sulfate, iron chloride, iron acetylacetonate complex, cobalt nitrate, cobalt acetate, cobalt sulfate, cobalt chloride, cobalt acetylacetonate complex, nickel nitrate, nickel acetate, nickel sulfate, nickel chloride, nickel acetylacetonate complex, manganese nitrate, manganese acetate, manganese sulfate, manganese chloride, manganese acetylacetonate complex, copper nitrate, copper acetate, copper sulfate, copper chloride, copper acetylacetonate complex, molybdenum nitrate, molybdenum acetate, molybdenum sulfate, molybdenum chloride, molybdenum acetylacetonate complex, tungsten nitrate, tungsten acetate, tungsten sulfate, tungsten chloride, tungsten acetylacetonate complex, tin nitrate, tin acetate, tin sulfate, tin chloride, tin acetylacetonate complex.

[0041] In the embodiment of the present invention, the feeding mass of the catalyst support is 0.8 - 2 times the sum of the feeding masses of the promoter precursor and the catalyst active center precursor.

[0042] In the embodiment of the present invention, the feeding molar ratio of the catalyst active center precursor to the promoter precursor is (3 - 15):1.

[0043] Further, the feeding molar ratio of the catalyst active center precursor to the promoter precursor is (8 - 15):1.

[0044] Still further, the feeding molar ratio of the catalyst active center precursor to the promoter precursor is (10 - 15):1.

[0045] In the embodiment of the present invention, the first solvent is ethanol and / or toluene.

[0046] In the embodiment of the present invention, the solvent of the promoter precursor solution is water.

[0047] Specifically, the second solvent is one or more of water, ethanol, methanol, butanol, isopropanol, toluene, N,N - dimethylformamide.

[0048] In the embodiment of the present invention, the second solvent is a mixed solvent of one or more of ethanol, methanol, butanol, isopropanol and water.

[0049] In the embodiment of the present invention, the drying temperatures in step (1), step (2) and step (3) are independently 100 - 150 °C, such as 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C.

[0050] In the embodiment of the present invention, the impregnations in step (1) and step (2) are respectively carried out by equal - volume impregnation. Preferably, the number of impregnation times in step (2) is 2 times.

[0051] In the embodiment of the present invention, the temperature of the heat treatment in step (3) is 160 - 220 °C, such as 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 195 °C, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C.

[0052] Specifically, the time of the heat treatment in step (3) is 1 - 48 h, more preferably 15 - 40 h, and still more preferably 15 - 30 h.

[0053] In the embodiment of the present invention, the time of the heat treatment in step (3) is 20 - 25 h.

[0054] In the embodiment of the present invention, the temperature of the calcination in step (4) is 150 - 250 °C.

[0055] Specifically, the time of the calcination in step (4) is 1 - 24 h.

[0056] In the embodiment of the present invention, the time of the calcination in step (4) is 3 - 6 h.

[0057] Specifically, the calcination in step (4) is carried out in one or more atmospheres of air, nitrogen or hydrogen.

[0058] In the embodiment of the present invention, the calcination in step (4) is carried out in an air atmosphere.

[0059] The second aspect of the present invention also provides a reactive distillation column system for catalytic cracking of the heavy components of butanol and octanol residues, and the reactive distillation column system is the reactive distillation column system mentioned above.

[0060] In an embodiment of the present invention, a gas phase outlet is provided at the top of the reactive distillation column, a liquid phase outlet is provided at the bottom of the reactive distillation column, a first liquid phase inlet is provided between the rectifying section and the stripping section, a second liquid phase inlet is provided at the upper part of the rectifying section, a gas phase inlet is provided between the stripping section and the reaction section, a gas phase outlet is provided in the reboiler, the cooler, the reflux drum and the reflux pump are respectively provided with a feed inlet and a discharge outlet, and the reactive distillation column system further includes a pipeline system. The pipeline system includes a feed pipeline connected to the first liquid phase inlet, a first connecting pipe for connecting the bottom of the reactive distillation column and the bottom of the reboiler, a second connecting pipe for connecting the gas phase outlet of the reboiler and the gas phase inlet, a third connecting pipe for connecting the gas phase outlet and the feed inlet of the cooler, a fourth connecting pipe for connecting the discharge outlet of the cooler and the feed inlet of the reflux drum, a fifth connecting pipe for connecting the discharge outlet of the reflux drum and the feed inlet of the reflux pump, a sixth connecting pipe for connecting the discharge outlet of the reflux pump and the second liquid phase inlet, a first discharge pipe connected to the discharge outlet of the reflux pump or the sixth connecting pipe, a second discharge pipe connected to the liquid phase outlet, and a gas pipeline for introducing an inert gas into the reactive distillation column system.

[0061] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0062] The present invention provides a cracking process capable of continuously catalytically cracking the heavy components of butanol and octanol residues. By using a supported heterogeneous catalyst with titanium oxide as the active center and a reactive distillation column system, the effect of long-term continuous cracking of the heavy components of butanol and octanol residues is improved, large-scale continuous cracking treatment of the heavy components of butanol and octanol residues is realized, the cracking cost of the heavy components of butanol and octanol residues will be significantly reduced, and the economic benefits of the heavy components of butanol and octanol residues will be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a schematic structural diagram of the reactive distillation column system;

[0064] Figure 2 is the XRD pattern of catalyst A;

[0065] Figure 3 is the nitrogen adsorption-desorption isotherm diagram of catalyst A;

[0066] Figure 4 is the XRD pattern of catalyst E;

[0067] Figure 5 is the nitrogen elution-desorption isotherm diagram of catalyst E;

[0068] Figure 6Figure showing the catalytic stability test results of catalyst A for continuous operation of 205 h.

[0069] Figure 1 In [Figure], 1 is the reactive distillation column; 11 is the rectifying section; 12 is the stripping section; 13 is the reaction section; 131 is the sampling port; 2 is the reboiler; 3 is the cooler; 4 is the reflux drum; 5 is the reflux pump; 61 is the feed pipeline; 62 is the first connecting pipe; 63 is the second connecting pipe; 64 is the third connecting pipe; 65 is the fourth connecting pipe; 66 is the fifth connecting pipe; 67 is the sixth connecting pipe; 68 is the first discharge pipe; 69 is the second discharge pipe; 70 is the gas pipeline. Detailed implementation manners

[0070] The above solution will be further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited by the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0071] For those without specific experimental steps or conditions indicated in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. Unless otherwise specified in the following embodiments, all raw materials are commercially available or prepared by conventional methods in this field.

[0072] In the present invention, unless otherwise specified, "%" refers to mass percentage.

[0073] The heavy components in the butanol and octanol residual liquid mentioned below are the bottom materials of the rectifying column after the rectifying column recovers C4 (butyraldehyde, butanol, butyric acid) and C8 (2-ethylhexaldehyde, 2-ethyl-2-hexenal, 2-ethylhexanol, 2-ethylhexanoic acid) components from the butanol and octanol residual liquid. After gas chromatography detection and analysis, the sum of the contents of C4 and C8 substances in the heavy components of the butanol and octanol residual liquid is 7% of the total mass of the heavy components of the butanol and octanol residual liquid.

[0074] The reactive distillation column system used in the following embodiments is as Figure 1As shown in the figure, it includes a reactive distillation column 1, a reboiler 2, a cooler 3, a reflux drum 4, a reflux pump 5 and a pipeline system. In this embodiment, the reactive distillation column 1 includes a rectifying section 11, a stripping section 12 and a reaction section 13 arranged in sequence from top to bottom. A catalyst for catalyzing the recombination and cracking of butanol and octanol residual liquid is filled in the reaction section 13. A sampling port 131 is provided below the reaction section 13 for temporarily sampling and monitoring the components of the reaction liquid flowing through the reaction section 13. A gas outlet is provided at the top of the reactive distillation column 1, and a liquid outlet is provided at the bottom of the reactive distillation column 1. A first liquid inlet is provided between the rectifying section 11 and the stripping section 12, a second liquid inlet is provided at the upper part of the rectifying section 11, and a gas inlet is provided between the stripping section 12 and the reaction section 13. The reboiler 2 is provided with a liquid inlet and a gas outlet. The cooler 3, the reflux drum 4 and the reflux pump 5 are respectively provided with a feed inlet and a discharge outlet. The pipeline system includes a feed pipeline 61 communicating with the first liquid inlet, a first connecting pipe 62 for connecting the bottom of the reactive distillation column 1 and the bottom of the reboiler 2, a second connecting pipe 63 for connecting the gas outlet of the reboiler 2 and the gas inlet, a third connecting pipe 64 for connecting the gas outlet and the feed inlet of the cooler 3, a fourth connecting pipe 65 for connecting the discharge outlet of the cooler 3 and the feed inlet of the reflux drum 4, a fifth connecting pipe 66 for connecting the discharge outlet of the reflux drum 4 and the feed inlet of the reflux pump 5, a sixth connecting pipe 67 for connecting the discharge outlet of the reflux pump 5 and the second liquid inlet, a first discharge pipe 68 communicating with the discharge outlet of the reflux pump 5 or the sixth connecting pipe 67, a second discharge pipe 69 communicating with the liquid outlet, and a gas pipeline 70 for introducing inert gas into the reactive distillation column system. The pressure inside the reactive distillation column 1 is 0.5 - 0.8 Mpa, and the atmosphere inside the reactive distillation column 1 is nitrogen. The number of effective trays in the rectifying section 11 is 28, the number of effective trays in the stripping section 12 is 3, and the height of the catalyst bed layer in the reaction section 13 is 1.8 m.

[0075] The catalysts used in the following examples were prepared and screened by the following methods:

[0076] Catalyst A:

[0077] (1) Dissolve 20 g of ferric nitrate nonahydrate in 30 mL of deionized water to obtain a ferric nitrate solution. Take 200 g of activated alumina spheres with a particle size of 0.5 - 1 mm and add them to the ferric nitrate solution. After equal-volume impregnation for 5 hours, first dry them to constant weight in a blast drying oven at 120 °C, and then calcine them in a flowing air atmosphere at 450 °C for 5 h to obtain a carrier material, that is, alumina spheres loaded with iron oxide.

[0078] (2) Mix 200 g of tetrabutyl titanate, 50 g of absolute ethanol, and 30 g of toluene evenly to obtain a mixed solution. Immerse the carrier material from step (1) in the mixed solution in two equal - volume portions. Specifically, take half of the volume of the mixed solution, add the carrier material from step (1), after impregnating for 5 hours, dry it in a forced - air drying oven at 120 °C for 12 hours. Add the obtained material to the other half of the volume of the mixed solution, impregnate again for 5 hours, and then dry it in a forced - air drying oven at 120 °C until constant weight.

[0079] (3) Add 50 g of the material obtained in step (2) to 140 g of deionized water, hydrothermal react at 200 °C in a hydrothermal autoclave for 24 hours. After cooling to room temperature, filter, wash with deionized water, and dry in a forced - air drying oven at 120 °C until constant weight.

[0080] (4) Calcinate the material obtained in step (3) in a flowing - air atmosphere at 180 °C for 3 hours, and then cool it to 30 °C in a flowing - air atmosphere and take it out to obtain catalyst A. From the XRD pattern of catalyst A ( Figure 2 ), it can be seen that titanium oxide is anatase and is well - dispersed on the catalyst carrier. According to the nitrogen adsorption - desorption isotherm of catalyst A ( Figure 3 ), using the BET formula, the specific surface area of catalyst A is calculated to be 100.3 m 2 / g. The pores in catalyst A are mainly macropores formed by particle accumulation.

[0081] Catalyst B:

[0082] (1) Dissolve 7 g of nickel acetate and 8 g of copper chloride in 50 mL of deionized water to obtain a mixed solution of nickel acetate and copper chloride. Take 200 g of activated silica spheres with a particle size of 0.5 - 1 mm and add them to the mixed solution of nickel acetate and copper chloride. After equal - volume impregnation for 5 hours, first dry it in a forced - air drying oven at 120 °C until constant weight, and then calcinate it in a flowing - air atmosphere at 450 °C for 5 h to obtain a carrier material, that is, silica supported with nickel oxide and copper oxide.

[0083] (2) Mix 100 g of isopropyl titanate, 20 g of absolute ethanol, and 20 g of toluene evenly to obtain a mixed solution. Add the carrier material from step (1) to the mixed solution. After equal - volume impregnation for 12 hours, dry it in a forced - air drying oven at 120 °C until constant weight.

[0084] (3) Add 50 g of the material obtained in step (2) to 140 g of deionized water, hydrothermal react at 180 °C in a hydrothermal autoclave for 24 hours. After cooling to room temperature, filter, wash with water, and dry in a forced - air drying oven at 120 °C until constant weight.

[0085] (4) Calcinate the material obtained in step (3) in a flowing - air atmosphere at 250 °C for 6 hours, and then cool it to 30 °C in a flowing - air atmosphere and take it out to obtain catalyst B.

[0086] Catalyst C:

[0087] (1) Mix 100 g of tetrabutyl titanate, 25 g of absolute ethanol, and 15 g of toluene evenly to obtain a mixed solution. Add 200 g of activated alumina spheres with a particle size of 0.5 - 1 mm to it, impregnate isovolumetrically for 5 hours, and then dry in a forced-air drying oven at 120 °C for 12 hours.

[0088] (2) Calcinate the material obtained in step (1) in a flowing air atmosphere at 550 °C for 3 hours, cool it to 30 °C in a flowing air atmosphere and take it out to obtain Catalyst C.

[0089] Catalyst D:

[0090] (1) Dissolve 20 g of ferric nitrate nonahydrate in 30 mL of deionized water to obtain a ferric nitrate solution. Take 200 g of activated alumina spheres with a particle size of 0.5 - 1 mm and add them to the ferric nitrate solution. After isovolumetric impregnation for 5 hours, first dry in a forced-air drying oven at 120 °C to constant weight, and then calcinate in a flowing air atmosphere at 450 °C for 5 h to obtain a carrier material, i.e., alumina spheres loaded with iron oxide.

[0091] (2) Mix 200 g of tetrabutyl titanate, 50 g of absolute ethanol, and 30 g of toluene evenly to obtain a mixed solution. Impregnate the carrier material obtained in step (1) with this mixed solution in two equal volumes. Specifically, take half of the volume of the mixed solution, add the carrier material obtained in step (1), impregnate for 5 hours, dry in a forced-air drying oven at 120 °C for 12 hours, add the obtained material to the other half of the volume of the mixed solution, impregnate again for 5 hours, and then dry in a forced-air drying oven at 120 °C to constant weight.

[0092] (3) Calcinate the material obtained in step (2) in a flowing air atmosphere at 180 °C for 3 hours, cool it to 30 °C in a flowing air atmosphere and take it out to obtain Catalyst D.

[0093] Catalyst E:

[0094] (1) Dissolve 20.0 g of ferric nitrate nonahydrate in 30 mL of deionized water to obtain a ferric nitrate solution. Take 200 g of activated alumina spheres with a particle size of 0.5 - 1 mm and add them to the ferric nitrate solution. After isovolumetric impregnation for 5 hours, first dry in a forced-air drying oven at 120 °C to constant weight, and then calcinate in a flowing air atmosphere at 450 °C for 5 h to obtain a carrier material, i.e., alumina spheres loaded with iron oxide.

[0095] (2) Mix 100 g of isopropyl titanate, 20 g of absolute ethanol, and 20 g of toluene evenly to obtain a mixed solution. Add the carrier material obtained in step (1) to this mixed solution, impregnate isovolumetrically for 12 hours, and then dry in a forced-air drying oven at 120 °C to constant weight.

[0096] (3) Add 50 g of the material obtained in step (2) to 140 g of deionized water, hydrothermal react at 200 °C for 24 hours in a hydrothermal autoclave, filter after cooling to room temperature, wash with deionized water, and dry to constant weight in a forced-air drying oven at 120 °C.

[0097] (4) Calcinate the material obtained in step (3) in a flowing air atmosphere at 550 °C for 3 hours, cool to 30 °C in a flowing air atmosphere and take out to obtain catalyst E. From the XRD pattern of catalyst E ( Figure 4 ), it can be seen that after increasing the calcination temperature, the crystallinity of titanium oxide has increased, the particles have also grown significantly, and agglomeration has occurred. From the nitrogen adsorption-desorption isotherm of catalyst E ( Figure 5 ), catalyst E has an obvious mesoporous structure. The specific surface area of catalyst E calculated by the BET formula is 150.8 m 2 / g. Compared with catalyst A, the loading of the active component of catalyst E is reduced.

[0098] Catalytic performance test

[0099] Use the catalysts prepared above to catalyze the heavy components of butanol-octanol residue respectively. The specific operation is as follows: Add 5 g of catalyst and 20 g of the heavy components of butanol-octanol residue to a high-pressure reactor. After replacing with nitrogen 3 times, fill with nitrogen to 5 bar, and react at 250 °C under stirring conditions of 600 rpm for 6 h. After cooling to 30 °C, first discharge the nitrogen in the high-pressure reactor, and take the reaction solution for gas chromatography detection and analysis. The sum of the contents of C4 and C8 substances in the reaction solution after the catalytic cracking reaction of catalyst A is 45.3%, the sum of the contents of C4 and C8 substances in the reaction solution after the catalytic cracking reaction of catalyst B is 43.4%, the sum of the contents of C4 and C8 substances in the reaction solution after the catalytic cracking reaction of catalyst C is 13.5%, the sum of the contents of C4 and C8 substances in the reaction solution after the catalytic cracking reaction of catalyst D is 29.53%, and the sum of the contents of C4 and C8 substances in the reaction solution after the catalytic cracking reaction of catalyst E is 30.1%.

[0100] Catalyst stability test

[0101] Use the catalysts prepared above to continuously flow-catalyze the heavy components of butanol-octanol residue respectively. The specific operation is as follows: Pack the catalyst in a 316L stainless steel round tube reactor with an inner diameter of 10 mm, an outer diameter of 12 mm, and a length of 320 mm to form a 25 mL fixed bed. After purging with nitrogen for 10 min, backpressure with nitrogen to 15 bar, heat the reactor to 250 °C, pump in the heavy components of butanol-octanol residue at a flow rate of 1 mL / min, continuously operate and take instantaneous samples of the reaction solution flowing out of the reactor at different time points for gas chromatography detection and analysis of the sum of the contents of C4 (butyraldehyde, butanol, butyric acid) and C8 (2-ethylhexanal, 2-ethyl-2-hexenal, 2-ethylhexanol, 2-ethylhexanoic acid).

[0102] Among them, the catalytic effect of catalyst A is stable. The change curves of the contents of C4 and C8 substances at different time points during 205 h of continuous operation are shown in Figure 6 . When the operation reaches 205 h, the sum of the contents of C4 and C8 substances in the instantaneous sample of the reaction solution is 48.52%. When continuously operating to 205 h, the sum of the contents of C4 and C8 substances in the instantaneous sample of the reaction solution still remains above 40%. The catalytic effect of catalyst B is relatively stable. When continuously operating to 200 h, the sum of the contents of C4 and C8 substances in the instantaneous sample of the reaction solution is 40.79%. When catalyst C continuously operates to 3 h, the sum of the contents of C4 and C8 substances in the instantaneous reaction sample is 15.2%. Since the initial activity of catalyst C is significantly lower than that of catalyst A and catalyst B, the continuous operation is terminated after 3 h. When catalyst D continuously operates to 3 h, the sum of the contents of C4 and C8 substances in the instantaneous reaction sample is 33.4%. Since the initial activity of catalyst D is significantly lower than that of catalyst A and catalyst B, the continuous operation is terminated after 3 h. When catalyst E continuously operates to 3 h, the sum of the contents of C4 and C8 substances in the instantaneous sample of the reaction solution is 31.1%. Since the initial activity of catalyst E is significantly lower than that of catalyst A and catalyst B, the continuous operation is terminated after 3 h.

[0103] Therefore, catalysts A and B with obvious catalytic effects and better long-term catalytic stability are selected for scale-up production and are used to fill the reaction section of the reactive distillation column to form a fixed bed layer. Example 1

[0104] This example provides a cracking process for the heavy components of butanol and octanol residue liquid, specifically: continuously introducing the heavy components of butanol and octanol residue liquid into the reactive distillation column system from the first liquid phase inlet between the rectifying section 11 and the stripping section 12. The heavy components of butanol and octanol residue liquid flow downward through the reaction section 13 under the action of gravity and are catalytically cracked by the catalyst in the reaction section 13. After the reaction, the material is introduced into the reboiler 2 from the bottom of the reactive distillation column 1. After being heated by the reboiler 2, the gaseous light components enter the reactive distillation column 1 from the gas phase inlet between the stripping section 12 and the reaction section 13 and rise to the top of the column, are discharged from the top outlet of the column and enter the cooler 3, and the liquid light components are obtained after condensation by the cooler 3. After the liquid light components flow through the reflux drum 4 and the reflux pump 5 in sequence, a part of them refluxes into the reactive distillation column 1 from the inlet above the rectifying section 11, and the other part is output from the reactive distillation column system through the first discharge pipe 68, which is the light component product. The reboiler 2 is used to heat the reaction solution, and the liquid components return to the bottom of the reactive distillation column 1. In order to maintain the material balance in the reactive distillation column 1, part of the bottom material is discharged through the first discharge pipe 68. This part is a conventional operation in the art and will not be elaborated herein.

[0105] In this embodiment, the catalyst loaded in the reaction section 13 is Catalyst A. The reactive distillation column 1 mainly controls the top temperature and the temperature of the reaction section 13. The top temperature is controlled at 185 - 200 °C, the temperature of the reaction section 13 is controlled at 260 - 275 °C, and the heating temperature of the reboiler 2 is set at 280 - 300 °C. The feed flow rate of the heavy components in the butanol - octanol residue liquid is 1.5 t / h, the effective residence time of the heavy components in the butanol - octanol residue liquid (the time for the heavy components in the butanol - octanol residue liquid to flow through the catalyst bed) is 0.5 h, and the reflux ratio of the reflux is controlled at 2. After gas chromatography detection and analysis, after the continuous operation of this embodiment for 200 h, the sum of the contents of C4 and C8 substances in the reaction liquid sample taken from the sampling port 131 is 44.71%. Example 2

[0106] This embodiment provides another cracking process for the heavy components in the butanol - octanol residue liquid, which is basically the same as Example 1, except that the top temperature is controlled at 190 - 205 °C and the temperature of the reaction section 13 is controlled at 265 - 280 °C. After gas chromatography detection and analysis, after continuous operation for 196 h, the sum of the contents of C4 and C8 substances in the reaction liquid sample taken from the sampling port 131 is 45.38%. Example 3

[0107] This embodiment provides another cracking process for the heavy components in the butanol - octanol residue liquid, which is basically the same as Example 1, except that the catalyst is different. The catalyst loaded in the reaction section 13 is Catalyst B. After gas chromatography detection and analysis, after the continuous operation of this embodiment for 196 h, the sum of the contents of C4 and C8 substances in the reaction liquid sample taken from the sampling port 131 is 35.46%.

[0108] The above - mentioned embodiments can achieve long - time, large - scale continuous cracking treatment of the heavy components in the butanol - octanol residue liquid, which will significantly reduce the cracking cost of the heavy components in the butanol - octanol residue liquid and improve the economic benefits of the heavy components in the butanol - octanol residue liquid.

[0109] The above - mentioned embodiments are only for explaining the technical concept and characteristics of the present invention. The purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A cracking process for the heavy components of butanol and octanol residue, characterized in that, The heavy components of the butanol and octanol residue liquid are introduced into a reactive distillation column system for cracking reaction. The reactive distillation column system includes a reactive distillation column (1), a reboiler (2), a cooler (3), a reflux drum (4) and a reflux pump (5). The reactive distillation column (1) includes a rectifying section (11), a stripping section (12) and a reaction section (13) arranged in sequence from top to bottom. A catalyst for catalyzing the cracking of the heavy components of the butanol and octanol residue liquid is loaded in the reaction section (13). The heavy components of the butanol and octanol residue liquid enter from the inlet between the rectifying section (11) and the stripping section (12), and cracking reaction occurs when flowing through the reaction section (13). After the reaction, the material is heated by the reboiler (2) to generate gaseous light components. The gaseous light components enter the reactive distillation column (1) from the inlet between the stripping section (12) and the reaction section (13) and rise to the top of the column, are discharged from the top outlet of the column and condensed by the cooler (3) to obtain liquid light components. After the liquid light components flow through the reflux drum (4) and the reflux pump (5) in sequence, a part of them refluxes into the reactive distillation column (1) from the inlet above the rectifying section (11), and the other part is output from the reactive distillation column system. Among them, the catalyst includes a catalyst carrier, a catalyst active center supported on the catalyst carrier, and a promoter. The catalyst active center is titanium oxide, the promoter is one or more of iron oxide, nickel oxide, or copper oxide, and the catalyst carrier is one or more of alumina, silica, magnesium aluminum hydrotalcite, hydroxyapatite, Y-type molecular sieve, A-type molecular sieve, ZSM-5, Beta-molecular sieve, coconut shell charcoal, XC-72R, XC-72. The mass of the titanium oxide is 10% - 20% of the total mass of the catalyst, and the mass of the promoter is 2% - 5% of the total mass of the catalyst. The specific surface area of the catalyst is 95 - 120 m 2 / g, The preparation method of the catalyst comprises the following steps: (1) Impregnate a catalyst support with a promoter precursor solution, dry it, and calcine it at 400 - 500 °C to obtain a support material loaded with the promoter. (2) Mix a catalyst active center precursor with a first solvent, then impregnate the support material loaded with the promoter, and dry it to obtain a catalyst precursor. (3) Heat-treat the catalyst precursor in a second solvent at 80 - 250 °C, wash it with water, and dry it to obtain a catalyst intermediate. (4) Calcine the catalyst intermediate at 150 - 250 °C to obtain the catalyst. Wherein, the catalyst active center precursor is one or more of isopropyl titanate, tetrabutyl titanate, titanium tetrachloride, etc.; the promoter precursor is one or more of iron nitrate, iron acetate, iron sulfate, iron chloride, iron acetylacetonate complex, nickel nitrate, nickel acetate, nickel sulfate, nickel chloride, nickel acetylacetonate complex, copper nitrate, copper acetate, copper sulfate, copper chloride, copper acetylacetonate complex, etc.

2. The cracking process of the heavy components of butanol and octanol residual liquid according to claim 1, characterized in that, The top temperature of the reactive distillation column (1) is 170 - 250 °C, the temperature of the reaction section is 190 - 300 °C, and the top temperature of the reactive distillation column (1) is lower than the temperature of the reaction section.

3. The cracking process of the heavy components in the butanol and octanol residue according to claim 1, characterized in that, The pressure inside the reactive distillation column (1) is 0.5 - 1.5 Mpa, and the atmosphere inside the reactive distillation column (1) is an inert gas atmosphere.

4. The cracking process of the heavy components in the butanol and octanol residual liquid according to claim 1, characterized in that, The feed flow rate of the heavy components of the butanol and octanol residue liquid is 1 - 2 t / h; and / or, the residence time of the reaction section (13) is 0.5 - 1 h.

5. The cracking process of the heavy components in the butanol and octanol residual liquid according to claim 1, characterized in that, The number of effective trays in the rectifying section (11) is 25 - 32; and / or, the number of effective trays in the stripping section (12) is 20 - 25.

6. The cracking process of the heavy components in the butanol and octanol residual liquid according to claim 1, wherein The reflux ratio of the reflux is 1 - 5.

7. The cracking process of the heavy components in the butanol and octanol residue according to claim 1, characterized in that, The mass of titanium oxide is 8% - 25% of the total mass of the catalyst, and the mass of the promoter is 0.5% - 5% of the total mass of the catalyst.

8. The cracking process of the heavy components in the butanol and octanol residue according to claim 1, characterized in that, The catalyst support is activated alumina spheres and / or activated silica spheres, and / or, the particle size of the catalyst support is 0.3 - 3 mm.

9. The cracking process of the heavy components in the butanol and octanol residue according to claim 1, characterized in that, The feeding mass of the catalyst support is 0.8 - 2 times the sum of the feeding masses of the promoter precursor and the catalyst active center precursor; and / or, the feeding molar ratio of the catalyst active center precursor to the promoter precursor is (10 - 15):1; and / or, the first solvent is ethanol and / or toluene; and / or, the solvent of the promoter precursor solution is water; and / or, the second solvent is one or more of water, ethanol, methanol, butanol, isopropanol, toluene, N,N-dimethylformamide.

10. The cracking process of the heavy components in the butanol and octanol residual liquid according to claim 1, characterized in that, The drying temperatures in step (1), step (2) and step (3) are independently 100 - 150 °C; and / or, the impregnation in step (1) and step (2) respectively adopts isovolumetric impregnation; and / or, the heat treatment temperature in step (3) is 160 - 220 °C; and / or, the heat treatment time in step (3) is 1 - 48 h; and / or, the calcination time in step (4) is 1 - 24 h; and / or, the calcination in step (4) is carried out in one or more atmospheres of air, nitrogen or hydrogen.

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