Process for the catalytic cracking of methylorganosilicon high boilers

Abstract

The present application provides a process and apparatus for the catalytic cracking of methyl organosilicon high boilers. By using a reaction apparatus having a riser reactor and an expansion section connected in series, cracking of methyl organosilicon high boilers under a molecular sieve catalyst in an atmospheric reaction system, continuous separation of deactivated catalyst, and further preferably continuous regeneration and reuse of the deactivated catalyst are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of comprehensive utilization of silicone by-products, and particularly relates to a process for catalytic cracking of methyl silicone high-boiling residue. BACKGROUND

[0002] Methyl silicone high-boiling residue (hereinafter referred to as "high-boiling residue") refers to a by-product with a boiling range of 80-215 DEG C produced in the process of directly producing methyl chlorosilane. The high-boiling residue mainly contains disilanes such as Si-Si, Si-C-Si and Si-O-Si, and a small amount of chlorosilane monomers, in addition to some chlorinated hydrocarbons and alkanes. Due to the complex composition and the presence of a large amount of Si-Cl bond compounds with high activity, the high-boiling residue is not easy to store. Most domestic enterprises use the high-boiling residue to produce high-boiling silicone oil, silicone waterproof agent, silicone resin and secondary processing products of silicone oil such as defoaming agent. However, the production of such low-end products generates a large amount of by-products, which brings more hidden troubles to enterprises in terms of HSE.

[0003] Cracking of the methyl silicone high-boiling residue to produce methyl chlorosilane monomers can convert the methyl silicone high-boiling residue into main products of organosilicon such as methyltrichlorosilane, dimethyldichlorosilane and trimethylchlorosilane, which is an ideal way to solve the comprehensive utilization of methyl silicone high-boiling residue.

[0004] In the early stage, foreign companies such as Dow Corning, GE and Wacker used high-temperature cracking method. As described in patents US2598435, US2681355 and US5877377A, the high-boiling residue was heated and vaporized, and then introduced into a stainless steel reactor with controllable temperature. Hydrogen chloride, hydrogen and chlorine were used as cracking gas at a temperature of 300-900 DEG C to produce methyl chlorosilane monomers. However, after the decomposition of the high-boiling residue, the powder was easy to accumulate in the reactor, causing blockage of the reactor and shortening the production cycle.

[0005] In view of the defects of high-temperature cracking, domestic and foreign companies have developed catalytic cracking technology for methyl silicone high-boiling residue. The cracking catalysts used include organic amine, aluminum-based, transition metal-based, molecular sieve and activated carbon-based, and metal phosphate-based. However, the catalytic cracking technology needs to use a high-pressure reactor, and cracking gas such as hydrogen and hydrogen chloride is introduced, so that the high-pressure operation has problems such as harsh reactor equipment, safety hazards and limited processing capacity.

[0006] From the perspective of process safety and long-term development, the normal (low) pressure reaction system and continuous operation process will be the development trend of catalytic cracking of methyl silicone high-boiling residue. SUMMARY

[0007] The application provides a catalytic cracking process and device of methyl organosilicon high-boiling substance, which realizes the cracking of methyl organosilicon high-boiling substance under the catalysis of molecular sieve, the continuous separation of deactivated catalyst, and the continuous regeneration and reuse of deactivated catalyst, and realizes the continuous catalytic cracking of methyl organosilicon high-boiling substance in an atmospheric reaction system by using a reaction device with a riser reactor and an expansion section connected in series.

[0008] The technical scheme of the application is as follows:

[0009] A catalytic cracking method of methyl organosilicon high-boiling substance, which uses a cracking reaction device with a riser reactor and an expansion section connected in series to crack methyl organosilicon high-boiling substance in the presence of a molecular sieve catalyst.

[0010] The riser reactor is a fluidized bed type reactor, and the molecular sieve catalyst is filled in the riser reactor.

[0011] The temperature in the riser reactor is 400-700 DEG C, preferably 550-650 DEG C; and the pressure in the riser reactor is 0-0.5 MPa, preferably 0-0.2 MPa.

[0012] According to the application, the temperature of the riser reactor can be provided and maintained by preheating the temperature of each material (including the catalyst, methyl organosilicon high-boiling substance, inert gas and / or cracking gas described below) entering the riser reactor, or by adding a heating device outside the riser reactor.

[0013] The diameter of the expansion section is 1.2-3 times, preferably 1.5-2 times, of the diameter of the riser reactor.

[0014] The temperature of the expansion section is 250-550 DEG C, preferably 300-400 DEG C; and the pressure of the expansion section is 0-0.3 MPa, preferably 0-0.2 MPa.

[0015] The molecular sieve catalyst is preferably USY molecular sieve, HZSM-5 molecular sieve, Y molecular sieve, LZY molecular sieve; and more preferably USY molecular sieve and HZSM-5 molecular sieve. In order to improve the catalytic cracking efficiency and selectivity of the molecular sieve, an element with cracking disproportionation activity can be further loaded on the molecular sieve, and the element includes but is not limited to nickel, iron, cobalt, zinc, molybdenum, manganese, aluminum, etc., and is preferably iron, zinc and / or molybdenum element.

[0016] In an embodiment of the application, the cracking reaction does not use additional cracking gas.

[0017] In one embodiment of the present application, the cracking reaction uses a cracking gas, which includes but is not limited to hydrogen chloride, hydrogen, C1-4 alkane, such as methane or ethane.

[0018] In one embodiment of the present application, an inert gas is introduced to fluidize the molecular sieve catalyst in the riser reactor. The inert gas refers to a gas that does not participate in and interfere with the catalytic cracking reaction, which includes but is not limited to nitrogen, argon, helium, and the like. Preferably, the inert gas is introduced into the riser reactor after being preheated, preferably preheated to 250-350°C.

[0019] According to the present application, the method further comprises burning and regenerating the deactivated molecular sieve catalyst and returning it to the riser reactor. In the present application, the gas generated after the high-boiling substance passes through the riser reactor enters the expansion section, and the gas velocity decreases, and the molecular sieve catalyst carried in the gas settles in the expansion section.

[0020] In one embodiment of the present application, the molecular sieve settled in the expansion section is sent to a catalyst regenerator to burn and regenerate the deactivated molecular sieve catalyst. According to the present application, the catalyst regenerator can be a fluidized bed, a rotary kiln, or other reaction devices known in the art for heating and burning, which can heat the substance by heating flue gas, or can burn by spraying fuel oil or fuel gas under the action of hot air, to achieve the purpose of activating the deactivated molecular sieve catalyst. The temperature in the catalyst regenerator is 500-850°C, preferably 650-750°C. The pressure in the catalyst regenerator is 0-0.5 MPa, preferably 0-0.2 MPa.

[0021] In some embodiments of the present application, fresh molecular sieve catalyst can be added according to the liquid level in the riser reactor, preferably the fresh molecular sieve catalyst is preheated before being added to the riser reactor, preferably the molecular sieve catalyst is preheated to 250-350°C. In one embodiment of the present application, the regenerator can be used to preheat fresh molecular sieve catalyst using the heat generated by burning the deactivated molecular sieve.

[0022] In some embodiments of the present application, the method further comprises reburning the fuel oil or fuel gas that is not fully combusted in the catalyst regenerator, and using the heat generated by the combustion for preheating various materials in the present application.

[0023] According to the present application, the method further comprises rectifying the gas discharged from the expansion section to separate the methyl organosilicon monomer obtained by cracking. According to the present application, various devices capable of rectification known in the art can be used for the rectification.

[0024] In some embodiments of the present application, the gas discharged from the enlarged section is further separated from solids before being subjected to rectification. The gas-solid separation device can be a dust filter device, such as a cyclone separator, a bag filter, a basket filter, a ceramic membrane filter, etc. known in the art. In one embodiment of the present application, a cyclone separator or a ceramic membrane filter is used.

[0025] According to the present application, the method further comprises returning the uncracked methyl organosilicon high-boiling residue obtained after rectification to the riser reactor for further cracking.

[0026] According to the present application, when inert gas and / or cracking gas is used in the method, the method further comprises returning the non-condensable gas (being inert gas and / or unreacted cracking gas) after rectification to the riser reactor. In one embodiment of the present application, the non-condensable gas is preheated before entering the riser reactor, preferably to 250-350°C.

[0027] The present application also provides a device for the catalytic cracking method of methyl organosilicon high-boiling residue, which comprises a cracking reaction device having a riser reactor and an enlarged section arranged in series, the riser reactor being used for filling molecular sieve catalyst and performing high-boiling residue catalytic cracking reaction.

[0028] The riser reactor is a fluidized bed type reactor.

[0029] The diameter of the enlarged section is 1.2-3 times, preferably 1.5-2 times, of the diameter of the riser reactor.

[0030] According to the present application, the device further comprises a catalyst regenerator, the catalyst regenerator being connected to the riser reactor through a catalyst slide valve, and the enlarged section being connected to the catalyst regenerator through a deactivated catalyst slide valve.

[0031] According to the present application, the catalyst regenerator is connected to an auxiliary combustion device, a catalyst storage device and a combustion device, respectively.

[0032] According to the present application, the lower end of the riser reactor is respectively provided with a gas feeding pipe and a high-boiling residue feeding pipe.

[0033] According to the present application, the upper end of the enlarged section is connected to a rectification system, which is used for separating methyl organosilicon monomers and uncracked high-boiling residue from the cracking reaction products.

[0034] In one embodiment of the present application, a gas-solid separation device is installed between the upper end of the enlarged section and the rectification system, which is used for separating catalyst solid powder and gas discharged from the cracking reaction device.

[0035] In one embodiment of the present application, the upper part of the rectification system is connected to a heat exchange device through a pipeline, and further connected to a gas feeding pipe of the riser reactor, for recycling the non-condensable gas separated from the rectification system into the cracking reaction.

[0036] In one embodiment of the present application, the lower part of the rectification system is connected to a high-boiling substance storage device through a pipeline, which is connected to a high-boiling substance heat exchange device, and further connected to a high-boiling substance feeding pipe of the riser reactor, for recycling the uncracked high-boiling substance separated from the rectification system into the cracking reaction.

[0037] The present application also provides a preparation method of the molecular sieve catalyst. The element having cracking-disproportionation activity can be loaded on the surface or channel of the molecular sieve by impregnation, atom transfer, ion exchange and other methods known in the art.

[0038] In some embodiments of the present application, the preparation method of the catalyst is as follows: the water-soluble salt of the element having cracking-disproportionation activity is prepared into a water solution with a suitable concentration, the molecular sieve or activated carbon is impregnated therein, and then taken out, dried and calcined to obtain the molecular sieve or activated carbon loaded with the element having cracking-disproportionation activity.

[0039] In the present application, the methyl silicone high-boiling substance refers to the by-product with a boiling range of 80-215℃ produced in the direct production of methyl chlorosilane, mainly composed of disilanes such as Si-Si, Si-C-Si and Si-O-Si, as well as a small amount of chlorosilane monomer, partial chlorinated hydrocarbon and alkane organic compounds.

[0040] In the present application, the pressure is all gauge pressure unless otherwise specified.

[0041] The present application has the following beneficial effects:

[0042] 1. The present application ingeniously realizes the separation of the deactivated molecular sieve from the cracking product gas by using a reaction device with a riser reactor and an expansion section connected in series.

[0043] 2. The use of the molecular sieve catalyst and the fluidized bed type reactor realizes the cracking of the methyl silicone high-boiling substance at normal pressure.

[0044] 3. Further increasing the catalyst regenerator and connecting the regenerator with the catalytic cracking device realizes the continuous separation, regeneration and reuse of the deactivated catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1The schematic diagram of the methyl organosilicon high-boiling residue cracking process in one embodiment of the present application is shown in the figure, wherein 1 is an auxiliary combustion furnace, 2 is a catalyst storage tank, 3 is a regenerator, 4 is a combustion boiler, 5 is a heat exchanger, 6 is a high-boiling residue storage tank, 7 is a high-boiling residue heat exchanger, 8 is a riser, 9 is an enlarged section, 10 is a cyclone separator, 11 is a rectification system, V1 is a deactivated catalyst slide valve, and V2 is a catalyst slide valve.

[0046] Figure 2 The high-boiling residue chromatogram of the process of Example 1

[0047] Figure 3 The online chromatogram of the cracked product of the process of Example 1

[0048] Figure 4 The chromatogram of the cracked product of the process of Example 1 DETAILED DESCRIPTION

[0049] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0050] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood as including values near the recited ones. For ranges of values, the endpoints of the ranges are included in the ranges, and the endpoints and individual points within the ranges are combinable to form new ranges, which are also included in the present disclosure.

[0051] In the present application, the equipment, devices, components, etc. can be commercially available or self-made according to the disclosure of the present application.

[0052] In the present application, some conventional operations and equipment, devices, components are omitted or only briefly described in order to highlight the key content.

[0053] Figure 1 The present application is one embodiment of the methyl organosilicon high-boiling residue cracking process and its device connection: the regenerator 3 is used for regenerating the cracking catalyst, and is connected with the auxiliary combustion furnace 1, the catalyst storage tank 2 and the combustion boiler 4, respectively.

[0054] The apparatus for performing the methyl organosilicon high-boiling residue cracking reaction comprises two parts, a riser 8 and an enlarged section 9, wherein the riser 8 is connected with the regenerator 3 through a catalyst slide valve V2, and the enlarged section 9 is connected with the regenerator 3 through a deactivated catalyst slide valve Vl. The lower end of the riser 8 is connected with a hot nitrogen gas (and, if cracking gas is used, also includes cracking gas) feed pipe and a high-boiling residue feed pipe. The upper end of the enlarged section 9 is connected with a cyclone separator 10, which is used to separate catalyst solid powder and gas from the cracked gas discharged from the enlarged section. The cyclone separator 10 is connected with a rectification system 11, which is used to separate methyl organosilicon monomer and uncracked high-boiling residue from the cracking reaction.

[0055] The upper part of the rectification system 11 is connected with the heat exchanger 5 through a pipe line, and further connected to the hot nitrogen gas feed pipe in the riser 8, for recycling the nitrogen gas (and, if cracking gas is used, also includes unreacted cracking gas) separated from the rectification system into the cracking reaction. The lower part of the rectification system 11 is connected with the high-boiling residue storage tank 6 through a pipe line, which is connected to the high-boiling residue heat exchanger 7, and further connected to the high-boiling residue feed pipe in the riser 8, for recycling the uncracked high-boiling residue separated from the rectification system into the cracking reaction.

[0056] The process flow and conditions for performing the methyl organosilicon high-boiling residue cracking using the apparatus are as follows:

[0057] 1. The fuel oil (such as diesel oil) is injected into the auxiliary combustion furnace 1 for combustion, and the flue gas generated is preheated to 300°C in the regenerator 3. A sufficient amount of catalyst is added from the catalyst storage tank 2 into the regenerator 3, and the temperature is continuously increased to 700°C.

[0058] 2. The nitrogen gas is preheated to 300°C in the heat exchanger 5, and then enters the riser 8 through a distribution plate to preheat the riser 8 to 300°C.

[0059] 3. The catalyst slide valve V2 is opened, and the catalyst at a temperature of 700°C is sent from the regenerator 3 to the riser 8. The methyl organosilicon high-boiling residue is preheated to 300°C in the high-boiling residue heat exchanger 7, and then sent to the riser 8 through a distribution plate.

[0060] 4. The temperature of the riser 8 is controlled at 550-600°C by adjusting the nitrogen gas flow rate, controlling the gas velocity and catalyst liquid level, and controlling the reaction time.

[0061] 5. The substance in the riser 8 enters the enlarged section 9, the gas velocity decreases, and the deactivated catalyst settles. When the catalyst deposits to a certain liquid level, the deactivated catalyst slide valve V1 is opened to send the deactivated catalyst to the regenerator 3. The cracked substance and nitrogen gas enter the cyclone separator 10 from the upper part of the enlarged section 9 and then enter the rectification device 11. Through rectification, organosilicon monomers such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane are separated. The non-condensed steam is heated to 300°C by the heat exchanger 5 and then enters the riser 8. The separated uncracked high-boiling substances are transferred to the high-boiling substance storage tank 6 and then sent to the riser 8 for secondary cracking after being preheated by the high-boiling substance heat exchanger 7.

[0062] 6. The catalyst settled in the enlarged section 9 enters the regenerator 3, where it is regenerated by burning off the carbon deposits on the surface of the catalyst through the injection of fuel oil (such as diesel) and hot air. The regenerated catalyst enters the riser 8 through the catalyst slide valve V2 to continue the reaction, and fresh catalyst is appropriately supplemented according to the liquid level in the riser 8.

[0063] 7. The incomplete combustion flue gas from the regenerator 3 enters the combustion boiler 4 for complete combustion.

[0064] The method for catalytic cracking of methyl organosilicon high-boiling substances provided by the present application preheats and activates the molecular sieve catalyst in the regenerator under normal pressure conditions, cracks the organosilicon high-boiling substances into methyl organosilicon monomers under certain temperature and pressure conditions in the riser, returns the deactivated catalyst to the regenerator for activation and regeneration, and realizes continuous cracking of methyl organosilicon high-boiling substances.

[0065] Example 1

[0066] The catalyst preparation and cracking experiment of this example includes the following steps:

[0067] Dissolve 8g of iron nitrate nonahydrate in 100g of deionized water, add 50g of USY molecular sieve with a diameter of 100μm, and place it in an ultrasonic bath for 8 hours of oscillation and immersion. After drying for 24 hours, place it in a tube furnace and calcine it at 700°C for 6 hours under nitrogen drying to obtain USY molecular sieve with iron active centers.

[0068] (1) Fill 50g of USY molecular sieve with iron active centers into a fixed fluidized bed;

[0069] (2) Purge the device at 0.5l / min for 30min;

[0070] (3) Set the preheater to 300°C, the reactor temperature to 600°C, and the pressure to normal pressure;

[0071] (4) After the temperature stabilizes, feed the methyl organosilicon high-boiling substances into the reactor at 0.86ml / min;

[0072] (5) On-line gas chromatography to detect product components and determine the cracking rate;

[0073] (6) Collect the reaction liquid and detect the methyl chlorosilane components by gas chromatography.

[0074] Example 2

[0075] The catalyst preparation and cracking experiment of this example includes the following steps:

[0076] Dissolve 6g of zinc nitrate hexahydrate in 100g of deionized water, add 50g of USY molecular sieve with a diameter of 100μm, and place it in an ultrasonic bath for 8 hours of oscillation immersion. Take it out and dry for 24 hours, and then place it in a tube furnace and calcine it at 700℃ for 6 hours under nitrogen drying to obtain USY molecular sieve with zinc as an acid active center.

[0077] (1) Load 50g of USY molecular sieve with zinc as an acid active center into a fixed fluidized bed;

[0078] (2) Purge the device at 0.5l / min for 30min;

[0079] (3) Set the preheater to 300℃, the reactor temperature to 600℃, and the pressure to normal pressure;

[0080] (4) After the temperature is stable, feed the methyl silicone high-boiling substance into the reactor at 0.86ml / min;

[0081] (5) On-line gas chromatography to detect product components and determine the cracking rate;

[0082] (6) Collect the reaction liquid and detect the methyl chlorosilane components by gas chromatography.

[0083] Example 3

[0084] The catalyst preparation and cracking experiment of this example includes the following steps:

[0085] Dissolve 6g of zinc nitrate hexahydrate in 100g of deionized water, add 50g of USY molecular sieve with a diameter of 100μm, and place it in an ultrasonic bath for 8 hours of oscillation immersion. Take it out and dry for 24 hours, and then place it in a tube furnace and calcine it at 700℃ for 6 hours under nitrogen drying to obtain USY molecular sieve with zinc as an acid active center.

[0086] (1) Load 50g of USY molecular sieve with zinc as an acid active center into a fixed fluidized bed;

[0087] (2) Purge the device at 0.5l / min for 30min;

[0088] (3) Set the preheater to 300℃, the reactor temperature to 600℃, and the pressure to normal pressure;

[0089] (4) After the temperature is stabilized, the methyl organosilicon high-boiling substance is introduced into the reactor at 0.86 ml / min;

[0090] (5) The product components are detected on-line by gas chromatography to determine the cracking rate;

[0091] (6) The reaction liquid is collected, and the methyl chlorosilane components are detected by gas chromatography.

[0092] Example 4

[0093] The catalyst preparation and cracking experiment of the present example includes the following steps:

[0094] 8 g of iron nitrate nonahydrate is dissolved in 100 g of deionized water, 50 g of HZSM-5 molecular sieve with a diameter of 100 μm is added, and the mixture is placed in an ultrasonic bath for 8 hours of oscillation and immersion, and then dried for 24 hours. The dried mixture is placed in a tube furnace and calcined at 700°C for 6 hours under nitrogen drying to obtain HZSM-5 molecular sieve with iron having acid active centers.

[0095] (1) 50 g of HZSM-5 molecular sieve with iron having acid active centers prepared in Example 1 is loaded into a fixed fluidized bed;

[0096] (2) The device is purged at 0.5 l / min for 30 min;

[0097] (3) The preheater is set to 300°C, the reactor temperature is set to 600°C, and the pressure is set to normal pressure;

[0098] (4) After the temperature is stabilized, the methyl organosilicon high-boiling substance is introduced into the reactor at 0.86 ml / min;

[0099] (5) The product components are detected on-line by gas chromatography to determine the cracking rate;

[0100] (6) The reaction liquid is collected, and the methyl chlorosilane components are detected by gas chromatography.

[0101] Example 5

[0102] The catalyst preparation and cracking experiment of the present example includes the following steps:

[0103] (1) 50 g of HZSM-5 molecular sieve with iron having acid active centers prepared in Example 1 is loaded into a fixed fluidized bed;

[0104] (2) The device is purged at 0.5 l / min for 30 min;

[0105] (3) The preheater is set to 300°C, the reactor temperature is set to 600°C, and the pressure is set to normal pressure;

[0106] (4) After the temperature is stabilized, the methyl organosilicon high-boiling substance is introduced into the reactor at 0.86 ml / min, and the cracking gas hydrogen is introduced into the reactor at 0.2 ml / min;

[0107] (5) On-line gas chromatography is used to detect the product components and determine the cracking rate;

[0108] (6) The reaction liquid is collected and gas chromatography is used to detect the methyl chlorosilane components.

[0109] Example 6

[0110] The catalyst preparation and cracking experiment of this example includes the following steps:

[0111] (1) 50 g of USY molecular sieve with acid active center iron prepared in Example 1 is loaded into a fixed fluidized bed;

[0112] (2) The device is purged at 0.5 l / min for 30 min;

[0113] (3) The preheater is set to 300°C, the reactor temperature is set to 600°C, and the pressure is set to normal pressure;

[0114] (4) After the temperature is stabilized, the methyl organosilicon high-boiling substance is fed into the reactor at 0.86 ml / min, and the cracking gas hydrogen chloride is fed into the reactor at 0.2 ml / min;

[0115] (5) On-line gas chromatography is used to detect the product components and determine the cracking rate;

[0116] (6) The reaction liquid is collected and gas chromatography is used to detect the methyl chlorosilane components.

[0117] Example 7

[0118] The method for catalytically cracking the methyl organosilicon high-boiling substance of this example includes the following steps:

[0119] (1) 50 g of USY molecular sieve with acid active center iron prepared in Example 1 is loaded into a fixed fluidized bed;

[0120] (1) The device is purged at 0.5 l / min for 30 min;

[0121] (2) The preheater is set to 300°C, the reactor temperature is set to 600°C, and the pressure is set to normal pressure;

[0122] (3) After the temperature is stabilized, the methyl organosilicon high-boiling substance is fed into the reactor at 0.86 ml / min;

[0123] (4) On-line gas chromatography is used to detect the product components and determine the cracking rate;

[0124] (5) The reaction liquid is collected and gas chromatography is used to detect the methyl chlorosilane components.

[0125] Example 8

[0126] The method for catalytically cracking the methyl organosilicon high-boiling substance of this example includes the following steps:

[0127] (1) 100 g of HZSM-5 molecular sieve of a silica-alumina carrier was packed into a fixed fluidized bed;

[0128] (1) The device was purged at 0.5 L / min for 30 min;

[0129] (2) The preheater was set to 300°C, the reactor temperature was 600°C, and the pressure was normal pressure;

[0130] (3) After the temperature was stabilized, methyl organosilicon high-boiling substances were introduced into the reactor at 0.86 ml / min;

[0131] (4) The product components were detected on-line by gas chromatography to determine the cracking rate;

[0132] (5) The reaction liquid was collected, and the methyl chlorosilane components were detected by gas chromatography.

[0133] Comparative Example

[0134] The method of catalytic cracking of methyl organosilicon high-boiling substances in the comparative example includes the following steps:

[0135] (1) The device was purged at 0.5 L / min for 30 min;

[0136] (2) The preheater was set to 300°C, the reactor temperature was 600°C, and the pressure was normal pressure;

[0137] (3) After the temperature was stabilized, methyl organosilicon high-boiling substances were introduced into the reactor at 0.86 ml / min;

[0138] (4) The product components were detected on-line by gas chromatography to determine the cracking rate;

[0139] (5) The reaction liquid was collected, and the methyl chlorosilane components were detected by gas chromatography.

[0140] Table 1 Comparison of effects of Examples 1-8 and the comparative example

[0141]

[0142] The device as described in Figure 1 Example 1 was used to perform continuous catalytic cracking:

[0143] (1) 40 kg of HZSM-5 type microspherical catalyst with acid active center iron prepared by the preparation method of Example 4 was loaded into the catalyst storage tank 2;

[0144] (2) The auxiliary combustion furnace 1 was ignited, and the flue gas generated was introduced into the regenerator 3;

[0145] (3) 5 kg of microspherical catalyst was added to the regenerator 3, and was fully fluidized, and the temperature was observed to be 700°C;

[0146] (4) The methyl silicone high-boiling residue is passed through the high-boiling residue heat exchanger 7 at a rate of 10 kg / h and heated to 300°C, and then passed into the riser 8, through the enlarged section 9, and into the cyclone separator 10 to the cooler, which is located between the cyclone separator and the rectification device, for cooling the cyclone-separated components to be rectified. The pressure of the riser 8 reactor is observed to confirm that it is in a normal state.

[0147] (5) The microspherical catalyst in the regenerator 3 is passed into the riser 8 at a rate of 1 kg / h through the catalyst slide valve V2. The temperature of the riser 8 and the fluidization state of the microspherical catalyst are observed. The methyl silicone high-boiling residue feed rate is increased to 30 kg / h. The temperature of the riser 8 and the fluidization state of the microspherical catalyst are observed. The flow rate of N2 is adjusted to ensure that the microspherical catalyst is fluidized and lifted to the enlarged section 9.

[0148] (6) The catalyst deposition state in the enlarged section 9 is observed. When the liquid level is reached, the deactivated catalyst slide valve V1 is opened to circulate the microspherical catalyst in the enlarged section 9 to the regenerator 3 for regeneration and heating.

[0149] (7) The liquid in the cooler is collected and analyzed by GC. The high-boiling residue feed rate and the catalyst feed rate are adjusted.

[0150] (8) The microspherical fluidization state in the regenerator 3 is observed. The spent catalyst at the bottom is promptly removed, and fresh catalyst is supplemented.

[0151] (9) The catalyst in the catalyst storage tank 2 and the high-boiling residue raw material in the high-boiling residue storage tank 6 are promptly supplemented.

[0152] (10) The reaction mother liquor received by the cooler is passed into the rectification system 11 for rectification to obtain dimethyldichlorosilane, methyltrichlorosilane, and other products.

[0153] The device is continuously operated for 120 h, a total of 4 tons of methyl silicone high-boiling residue is passed in, 3.8 tons of liquid-phase material is obtained, 1.2 tons of dimethyldichlorosilane and 1 ton of methyltrichlorosilane are obtained by fractionation, and other low-boiling residues are passed into the disproportionation unit.

[0154] The chromatogram of the high-boiling residue used in this example is shown in Figure 2 The chromatograms of the products after cracking are shown in Figure 3 and Figure 4 , wherein Figure 3 is used to illustrate the primary cracking rate, Figure 4 is used to illustrate the selectivity of cracking. Through chromatographic analysis, the primary cracking rate can reach 92%, and the selectivity of methyl chlorosilane can reach 74%, of which methyltrichlorosilane is 33%, dimethyldichlorosilane is 38%, and trimethylchlorosilane is 3%.

[0155] Notes:

[0156] 1. Cracking rate = 100% - high-boiling content in liquid product / high-boiling content in raw material x 100%

[0157] 2. The content of each component is determined by gas chromatography.

[0158] The above describes the embodiments of the present application. However, the present application is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A process for the catalytic cleavage of methylorganosilicon high boilers, characterized in that, The cracking reaction of methyl organosilicon high-boiling residue is carried out in the presence of a molecular sieve catalyst in a cracking reaction device with a riser reactor and an expansion section arranged in series; The riser reactor is a fluidized bed type reactor, and the molecular sieve catalyst is filled in the riser reactor; The diameter of the expansion section is 1.2-3 times of the diameter of the riser reactor; The temperature in the riser reactor is 550-650℃, and the pressure is 0-0.5 MPa; The temperature in the expansion section is 250-550℃, and the pressure is 0-0.3 MPa; The molecular sieve catalyst is USY molecular sieve, HZSM-5 molecular sieve, Y molecular sieve or LZY molecular sieve, and an element with cracking disproportionation activity is loaded on the molecular sieve catalyst, and the element is selected from nickel, iron, cobalt, zinc, molybdenum or manganese; The methyl organosilicon high-boiling residue refers to a by-product with a boiling range of 80-215℃ produced in the process of directly producing methyl chlorosilane.

2. The catalytic cracking process of claim 1 wherein, The pressure in the riser reactor is 0-0.2 MPa; the temperature in the expansion section is 300-400℃, and the pressure is 0-0.2 MPa.

3. The catalytic cracking process as claimed in claim 1 or 2, characterized in that, The diameter of the expansion section is 1.5-2 times of the diameter of the riser reactor.

4. The catalytic cracking process as claimed in claim 1 or 2, characterized in that, The cracking reaction does not use additional cracking gas, or the cracking reaction uses cracking gas selected from hydrogen chloride, hydrogen, C1-4 alkane.

5. The catalytic cracking process as set forth in claim 1 or 2, characterized in that, The method further comprises sending the molecular sieve catalyst settled in the expansion section to a catalyst regenerator, burning and decarburizing the deactivated molecular sieve catalyst to regenerate, and returning to the riser reactor.

6. The catalytic cracking process of claim 5 wherein, The temperature in the catalyst regenerator is 500-850℃, and the pressure is 0-0.5 MPa.

7. The catalytic cracking process as set forth in claim 6 wherein, The temperature in the catalyst regenerator is 650-750℃, and the pressure is 0-0.2 MPa.

8. The catalytic cracking process as set forth in claim 1 or 2, characterized in that, The method further comprises rectifying the gas discharged from the expansion section to separate the methyl organosilicon monomer obtained by cracking.

9. The catalytic cracking process as set forth in claim 8 wherein, The gas discharged from the expansion section is separated to remove the solids therefrom by a gas-solid separation device before rectification.

10. The catalytic cracking process as set forth in claim 8, characterized in that, The method further comprises returning the uncracked methyl organosilicon high-boiling residue obtained after rectification to the riser reactor for re-cracking.

11. The catalytic cracking process as set forth in claim 8 wherein, The method further comprises returning the non-condensable gas after rectification to the riser reactor.

12. An apparatus for the catalytic cracking of methyl organosilicon high boilers according to the process of any one of claims 1-11, characterized in that, The device comprises a cracking reaction device with a riser reactor and an expansion section arranged in series, the riser reactor is used to fill the molecular sieve catalyst and carry out the catalytic cracking reaction of high-boiling residue; The riser reactor is a fluidized bed type reactor; The diameter of the expansion section is 1.2-3 times of the diameter of the riser reactor; The lower end of the riser reactor is respectively provided with a gas feeding pipe and a high-boiling residue feeding pipe; The upper end of the expansion section is connected with a rectification system for separating the methyl organosilicon monomer and uncracked high-boiling residue in the cracking reaction product.

13. The apparatus of claim 12, wherein, The diameter of the expansion section is 1.5-2 times of the diameter of the riser reactor.

14. The apparatus of claim 12 or 13, wherein, The device comprises a catalyst regenerator connected with the riser reactor through a catalyst slide valve, and the expansion section is connected with the catalyst regenerator through a deactivated catalyst slide valve; the catalyst regenerator is connected with an auxiliary combustion device, a catalyst storage device and a combustion device respectively.

15. The apparatus of claim 12 or 13, wherein, A gas-solid separation device is installed between the upper end of the expansion section and the rectification system, which is used to separate the catalyst solid powder and gas discharged from the pyrolysis reaction device.

16. The apparatus of claim 12 or 13, wherein, The upper part of the rectification system is connected with a heat exchange device through a pipeline, and further connected to the gas feeding pipe of the riser reactor, which is used to recycle the non-condensable gas separated from the rectification system into the pyrolysis reaction.

17. The apparatus of claim 12 or 13, wherein, The lower part of the rectification system is connected with a high-boiling substance storage device through a pipeline, which is connected to a high-boiling substance heat exchange device, and further connected to the high-boiling substance feeding pipe of the riser reactor, which is used to recycle the un-pyrolyzed high-boiling substance separated from the rectification system into the pyrolysis reaction.

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