Preparation process and preparation device of sec-butyl acetate

Abstract

The invention discloses a preparation process and a preparation device of sec-butyl acetate, and relates to the field of chemical engineering, and the preparation process comprises the following steps: step 1, raw material concentration; step 2, primary esterification reaction; step 3, secondary esterification reaction; 4, carrying out azeotropic distillation separation on acetic acid, SBA and water; step 5, separating an SBA product; 6, refining and recycling acetic acid; the device comprises a header pipe, a deisobutanizer, a first esterification reactor, a first reverse mixer, a first reverse decarburization fourth tower, a second esterification reactor, a second reverse mixer, a decarburization fourth tower, a C4 water washing tower, an azeotropic rectifying tower, an ester product tower, a steam generator, an acetic acid refining tower, an acetic acid heavy component removal tower return tank, a heavy component alkali washing layering tank and a heavy component buffer tank. A tail gas alkali washing tank and a dirty oil storage tank; according to the present invention, the original four esterification reactors connected in series are changed into the two-stage esterification, such that the esterification reaction depth is deepened, and the sec-butyl acetate production capacity is substantially improved.

Description

Technical Field

[0001] The invention mainly relates to the technical field of chemical industry, and specifically relates to a preparation process and a preparation device of sec-butyl acetate. Background Art

[0002] There are two methods for producing butyl acetate used in industrial production: alcohol esterification and butene-acetic acid addition. In recent years, due to the rapid development of the petroleum industry, isobutylene has been well utilized and the concentration of by-product butene components has been improved. In particular, due to the development of the polyethylene industry, n-butene can be separated as a comonomer to obtain a carbon four by-product with a purity of more than 95%, which is currently commonly used as a liquefied gas component.

[0003] Currently, sec-butyl acetate is produced by the reaction of acetic acid with n-butene, cis-butene and trans-butene. However, due to the low conversion rate of cis-butene and trans-butene, the product output is low. Therefore, this technology is studied to improve the conversion rate of sec-butyl acetate equipment. Summary of the invention

[0004] Based on this, the object of the present invention is to provide a preparation process and a preparation device of sec-butyl acetate to solve the technical problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A process for preparing sec-butyl acetate comprises the following steps: Step 1, the raw material is concentrated, and the etherified C4 raw material is sent to the deisobutanizer through the main pipe. The deisobutanizer comes out from the top of the tower and is cooled to the isobutane tower reflux tank, and then is transported to the tank area through the isobutane tower reflux pump. The concentrated C4 is pumped to the first esterification reactor through the isobutane tower bottom pump; Step 2, primary esterification reaction, the acetic acid raw material is pumped out from the reflux tank of the acetic acid refining tower by a feed pump, sent to the acetic acid preheater and heated to the preheating temperature, the carbon four at the bottom of the deisobutanizer is heated in the preheater, mixed with acetic acid and enters the first esterification reactor for esterification reaction, and all the reaction products enter the first decarbonization four tower for heavy fraction separation, the heavy fraction is separated from the bottom of the tower and enters the azeotropic distillation tower, and the unreacted carbon four comes out from the top of the tower and is condensed to the secondary esterification reaction; Step 3, secondary esterification reaction, the unreacted C4 is sent to the secondary esterification through a pump under pressure, mixed with acetic acid from the reflux tank of the acetic acid refining tower and preheated, and then sent to the second esterification reactor for esterification reaction, and all the reaction products enter the decarbonization tower for heavy fraction separation. The pressure at the top of the decarbonization tower adopts a thermal bypass control process, and the C4 liquid condensed at the top of the tower is pumped out by the reflux pump of the decarbonization tower, a part of which is sent to the top of the tower as reflux, and a part of which is sent to the C4 water washing tower. The acid-containing extraction water of the water washing tower is sent to the azeotropic distillation tower for recovery and reuse, and the C4 after water separation is sent to the liquefied gas storage tank in the tank area; Step 4, acetic acid, SBA and water are separated by azeotropic distillation. The azeotropic distillation tower uses water as an azeotropic agent. Through azeotropic distillation, acetic acid and carbon twelve are separated from SBA and carbon eight olefins. The decarbonization tower and the bottom material of the decarbonization tower enter the azeotropic distillation tower at the same time. The SBA, carbon eight, water, etc. evaporated from the top of the tower are condensed and cooled and then separated. The water phase is pumped through two routes: one part is refluxed and the other part is pumped into the carbon four water washing tower; the ester phase is crude ester, which is pumped out by two routes: one part is refluxed and the other part is pumped into the ester product tower. The crude acetic acid at the bottom of the tower is sent to the acetic acid refining tower for treatment; Step 5, SBA product separation, the crude ester is sent from the azeotropic distillation tower to the ester product tower, the carbon eight and water light fractions are evaporated from the top of the tower, condensed and cooled to separate, the water phase is heated by a steam generator and then returned to the ester product tower as stripping steam, the light fraction is pressurized by the ester product tower reflux pump and then divided into two paths: one part is refluxed, and the other part is sent to the tank area, SBA is extracted from the bottom of the tower, and after heat exchange and cooling, it is sent to the SBA tank area; Step 6, acetic acid refining and recovery, the crude acetic acid from the bottom of the azeotropic distillation tower is pumped into the acetic acid refining tower, the acetic acid is evaporated from the top of the tower, condensed and cooled, and pumped out by the acetic acid refining tower reflux pump, part of which is used for reflux, and part of which is fed to the acetic acid feed pump as esterification feed; The amount of high-boiling materials at the bottom of the tower is very small, and the operation is carried out in an intermittent manner. When the acetic acid content is concentrated to the required level, it is cooled in a heavy fraction cooler, pumped out by a heavy material alkaline wash feed pump, mixed with water pumped out by a heavy material alkaline wash circulation pump, washed, and then enters a heavy material alkaline wash stratification tank for liquid stratification. After separation, it is pumped to the tank area by a heavy material delivery pump.

[0006] Specifically, in the step 1, the deisobutanizer is provided with 60 layers of trays, the bottom temperature is 70° C., the top temperature is 60° C., and the top pressure is 0.8 MPa.

[0007] Specifically, in step 2, the first esterification reactor is composed of two primary esterification sensors connected in parallel and then connected in series to a first pre-esterification reactor, the reaction temperature is set at 70°C, the reaction pressure is 1.4MPa, and the temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to constant temperature; The reaction products are mainly: SBA, C8, C12, acetic acid and unreacted C4; The first decarbonization tower separates the unreacted C4 from heavy fractions such as acetic acid, SBA, C8 olefins, and C12 olefins.

[0008] Specifically, in step 3, the second esterification reactor is composed of two secondary esterification reactors connected in parallel and then connected in series with a second pre-esterification reactor, and the temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to constant temperature, and the reaction products mainly include: SBA, carbon eight, carbon twelve, acetic acid and unreacted carbon four; The decarbonization tower separates the unreacted C4 from heavy fractions such as acetic acid, SBA, C8 olefins, and C12 olefins; In addition, the C4 water washing tower uses the water phase from the azeotropic distillation tower as the extractant to extract the trace acetic acid in the C4 with water to meet the liquefied gas quality and the corrosion requirements of the transmission pipeline and equipment.

[0009] Specifically, in step six, the crude acetic acid at the bottom of the azeotropic distillation tower contains high-boiling substances such as carbon dodecene. In order to avoid the reduction of the activity and life of the catalyst caused by metal cations, the crude acetic acid needs to pass through an acetic acid refining tower, and the high-boiling substances and metal ions are removed from the bottom of the tower, and refined acetic acid is extracted from the top of the tower.

[0010] According to the technical division of the above-mentioned process for preparing sec-butyl acetate, a preparation device for the process for preparing sec-butyl acetate will also be provided, comprising a main pipe, a deisobutanizer, a first esterification reactor, a first reverse mixer, a first reverse decarbonization tower, a second esterification reactor, a second reverse mixer, a decarbonization tower, a carbon four water washing tower, an azeotropic distillation tower, an ester product tower, a steam generator, an acetic acid refining tower, an acetic acid deheaving tower reflux tank, a heavy material alkali washing stratification tank, a heavy material buffer tank, a tail gas alkali washing tank and a waste oil storage tank; The main pipe is connected to the feed port of the deisobutanizer. The top of the deisobutanizer is provided with an isobutane tower top cooler and an isobutane tower reflux tank, which are connected through pipelines. The discharge port of the isobutane tower reflux tank is connected to an isobutane tower reflux pump. The pump outlet of the isobutane tower reflux pump is respectively connected to the top of the deisobutanizer and the isobutane tank area through pipelines. The bottom of the deisobutanizer is connected to the C tank area, the first reverse mixer and the second reverse mixer in the form of series and parallel connection through the isobutane tower bottom pump. The inlet pipeline of the first reverse mixer is connected to the first reverse mixer. The outlets of the acid preheater and the first C4 preheater are connected in parallel by pipelines to two reverse mixers and an acetic acid feed pump. The pump inlet of the acetic acid feed pump is connected to the reflux tank of the acetic acid deweighting tower through a pipeline. The first C4 preheater is connected in series with a coalescer and a C4 filter by a pipeline. The main pipe and the bottom of the deisobutane tower are connected to the C4 filter through pipelines. The outlet pipeline of the first reverse mixer is connected to the first esterification reactor, and the discharge pipeline of the first esterification reactor is connected to the feed port of the first decarbonization tower through a pipeline.

[0011] The technical solution is specific, the top of the first reverse decarbonization four tower is connected to the first reverse decarbonization four tower top condenser and the first reverse decarbonization four tower top reflux tank in sequence by pipelines, the first reverse decarbonization four tower top reflux tank is respectively connected to the first reverse decarbonization four tower reflux pump and the inlet of the second reverse carbon four feed pump through two pipelines, the outlet of the first reverse decarbonization four tower reflux pump is respectively connected to the top of the first reverse decarbonization four tower and the second reverse mixer inlet pipeline through pipelines, the bottom of the first reverse decarbonization four tower is respectively connected to the azeotropic distillation tower and the pipeline network through pipelines, the second reverse carbon four feed pump is connected to the second reverse mixer inlet pipeline through a pipeline and is connected in parallel with the pipeline connected to the carbon four water washing tower, the second reverse mixer inlet pipeline is connected in parallel with the acetic acid feed pump and the pump outlet pipeline of the isobutane tower bottom pump, the second reverse mixer outlet is connected to the second esterification reactor through the second reverse feed heater, and the discharge pipeline of the second esterification reactor is connected to the decarbonization four tower feed port.

[0012] The technical solution is specific, the top of the decarbonization four tower is connected to the decarbonization four tower top condenser and the decarbonization four tower top reflux tank in sequence by pipelines, the outlet of the decarbonization four tower top reflux tank is connected to the decarbonization four tower reflux pump, the decarbonization four tower reflux pump is respectively connected to the top of the decarbonization four tower and the feed inlet of the carbon four water washing tower through pipelines, the bottom of the decarbonization four tower is respectively connected to the azeotropic distillation tower and the pipeline network through pipelines, the top of the carbon four water washing tower is connected to the water-washed carbon four buffer tank by a pipeline, the outlet of the water-washed carbon four buffer tank is connected to the carbon four delivery pump, the pump outlet of the carbon four delivery pump is connected to the liquefied gas storage tank in the tank area through a pipeline, and the bottom of the carbon four water washing tower is connected to the azeotropic distillation tower through a pneumatic regulating valve.

[0013] The technical solution is specific, the top of the azeotropic distillation tower is connected to the azeotropic distillation tower top condenser and the azeotropic distillation tower top stratification tank by pipelines, the azeotropic distillation tower top stratification tank is respectively connected to the stratified water phase delivery pump and the stratified ester phase delivery pump, the stratified water phase delivery pump is respectively connected to the carbon four water washing tower, the waste oil storage tank and the top of the azeotropic distillation tower through pipelines, the stratified ester phase delivery pump is respectively connected to the feed heat exchanger of the ester product tower and the top of the azeotropic distillation tower through pipelines, the bottom end of the azeotropic distillation tower is respectively connected to the pipeline network and the azeotropic distillation tower bottom delivery pump, the azeotropic distillation tower bottom delivery pump is connected to the acetic acid refining tower, and the tower plate of the azeotropic distillation tower is a high-efficiency floating valve tower plate; The top of the ester product tower is connected to an ester product tower condenser and an ester product reflux tank by a pipeline, the exhaust port of the ester product reflux tank is connected to a tail gas alkali washing tank, the ester product reflux tank is respectively connected to an ester tower reflux tank water delivery pump and a pump inlet of the ester product tower reflux pump, the pump outlet of the ester tower reflux tank water delivery pump is respectively connected to a steam generator and a feed port pipeline of a stratification tank at the top of an azeotropic distillation tower, and the pump outlet of the ester product tower reflux pump is respectively connected to a tank area and the top of the ester product tower.

[0014] The technical solution is specific, the top of the acetic acid refining tower is connected in series with an acetic acid refining tower low-temperature hot water heat exchanger, an acetic acid refining tower condenser and an acetic acid de-weighting tower reflux tank by a pipeline, the exhaust port of the acetic acid de-weighting tower reflux tank is connected to the tail gas alkali washing tank, and the acetic acid de-weighting tower reflux tank is connected to the top of the acetic acid refining tower through an acetic acid refining tower reflux pump, the bottom end of the acetic acid refining tower is connected to the pipeline network and the heavy material alkali washing stratification tank through pipelines, the heavy material alkali washing stratification tank is connected to the heavy material buffer tank, and the heavy material buffer tank is connected to the heavy material tank area through a heavy material delivery pump.

[0015] In summary, the present invention mainly has the following beneficial effects: 1. The olefins in the C4 after etherification are concentrated by deisobutanization tower and then reacted in two reactors to make the olefin conversion rate in C4 reach more than 75%; 2. The catalyst has high activity and good stability. The reaction part uses circulating hot water for heating, which has low operating costs. 3. The addition of a low-temperature hot water system has greatly reduced the use of steam and circulating water, and greatly reduced the energy consumption of the device.

[0016] 4. Some newly added and updated low-pressure heat exchangers use plate heat exchangers, which greatly saves floor space and investment costs; 5. Use solid acid catalyst, which is non-toxic and harmless, and the production environment is friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the steps of the present invention; Figure 2 This is a schematic flow chart of the deisobutane portion of the present invention; Figure 3 This is a partial principle flow chart of the primary esterification reaction of the present invention; Figure 4 This is a partial principle flow chart of the one-to-one carbon four separation and the secondary esterification reaction of the present invention; Figure 5 This is a principle flow chart of the carbon four separation part of the present invention; Figure 6 This is a partial principle flow chart of the azeotropic separation of acetic acid and ester of the present invention; Figure 7 This is a schematic flow chart of the ester product separation part of the present invention; Figure 8 This is a principle flow chart of the acetic acid recovery part of the present invention; Fig. 9 It is a flow chart of the hot water circulation and tail gas washing principle of the present invention; Fig.10 This is a diagram of the operating conditions of the esterification reaction of the present invention; Fig.11This is a diagram of the main tower operating conditions of the present invention.

[0018] Description of the drawings: 1. Main pipe; 2. Deisobutanizer; 201. Isobutane tower top cooler; 202. Isobutane tower reflux tank; 203. Isobutane tower reflux pump; 204. Deisobutanizer bottom pump; 3. First esterification reactor; 301. First mixer; 302. First acetic acid preheater; 303. First C4 preheater; 304. Acetic acid feed pump; 305. C4 filter; 306. Coalescer; 4. First reaction decarbonization tower; 401, first reaction decarbonization tower top condenser; 402, first reaction decarbonization tower top reflux tank; 4021, first reaction decarbonization tower reflux pump; 4022, second reaction carbonization tower feed pump; 403, second reaction mixer; 4031, second reaction feed heater; 5, second esterification reactor; 6, decarbonization tower; 601, decarbonization tower top condenser; 602, decarbonization tower top reflux tank; 6021, decarbonization tower reflux pump pump; 7, C4 water washing tower; 701, water-washed C4 buffer tank; 702, C4 delivery pump; 8, azeotropic distillation tower; 801, azeotropic distillation tower top condenser; 802, azeotropic distillation tower top stratification tank; 8021, stratified water phase delivery pump; 8022, stratified ester phase delivery pump; 803, azeotropic distillation tower bottom delivery pump; 9, ester product tower; 901, ester product tower condenser; 902, ester product reflux tank; 902 1. Ester tower reflux tank water delivery pump; 9022. Ester product tower reflux pump; 903. Steam generator; 10. Acetic acid refining tower; 1001. Acetic acid refining tower low-temperature hot water heat exchanger; 1002. Acetic acid refining tower condenser; 1003. Acetic acid deweighting tower reflux tank; 1004. Acetic acid refining tower reflux pump; 1011. Heavy material alkali washing and stratification tank; 1012. Heavy material buffer tank; 1013. Heavy material delivery pump. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] The following describes an embodiment of the present invention based on its overall structure. Example

[0021] See also Figure 1-9 As shown, a process for preparing sec-butyl acetate comprises the following steps: Step 1, raw material concentration, etherified C4 raw material is sent to deisobutanizer 2 through main pipe 1, deisobutanizer comes out from the top of the tower, is cooled and sent to isobutane tower reflux tank 202, and then is transported to the tank area through isobutane tower reflux pump 203, and the concentrated C4 is sent to the first esterification reactor 3 through isobutane tower bottom pump 204. There are 60 tower plates in deisobutanizer 2, the bottom temperature is 70°C, the top temperature is 60°C, and the top pressure is 0.8MPa.

[0022] Step 2, primary esterification reaction, the acetic acid raw material is pumped out from the reflux tank of the acetic acid refining tower 10 by the feed pump, sent to the acetic acid preheater and heated to the preheating temperature, the carbon four at the bottom of the deisobutanizer 2 is heated by the preheater, and then mixed with acetic acid to enter the first esterification reactor 3 for esterification reaction, the first esterification reactor 3 is composed of two primary esterification sensors connected in parallel and then connected in series with the first pre-esterification reactor, the reaction setting temperature is 70°C, the reaction pressure is 1.4MPa, the temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to constant temperature, the esterification reaction process is exothermic (70°C~100°C), the esterification reaction is carried out under full liquid phase conditions, and the reaction pressure is controlled by the reactor outlet pressure control valve; The reaction products are mainly: SBA, C8, C12, acetic acid and unreacted C4; The first decarbonization tower 4 separates the undecarbonized four from heavy fractions such as acetic acid, SBA, eight carbon olefins, and twelve carbon olefins. The heavy fractions are separated from the bottom of the tower and enter the azeotropic distillation tower 8. The undecarbonized four comes out from the top of the tower and is condensed to the secondary esterification reaction. Step 3, secondary esterification reaction, the unreacted C4 is sent to the secondary esterification by a pump under pressure, mixed with acetic acid from the reflux tank of the acetic acid refining tower 10 and preheated, and then sent to the second esterification reactor 5 for esterification reaction. The second esterification reactor 5 is composed of two secondary esterification reactors connected in parallel and then connected in series with a second pre-esterification reactor. The temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to constant temperature. The esterification reaction process is an exothermic reaction (70°C~100°C). The esterification reaction is carried out under full liquid phase conditions, and the reaction pressure is controlled by the reactor outlet pressure control valve; The reaction products are mainly: SBA, C8, C12, acetic acid and unreacted C4; All the reaction products enter the decarbonization tower 6, which separates the unreacted C4 from heavy fractions such as acetic acid, SBA, C8 olefins, and C12 olefins. The top pressure of the decarbonization tower 6 adopts a thermal bypass control process. The C4 liquid condensed at the top of the tower is pumped out by the decarbonization tower reflux pump 6021, a part of which is sent to the top of the tower as reflux, and a part of which is sent to the C4 water washing tower 7. The C4 water washing tower 7 uses the water phase from the azeotropic distillation tower 8 as an extractant to extract the trace acetic acid in the C4 with water to meet the quality of liquefied gas and the corrosion requirements of the transmission pipeline and equipment. The acid-containing extraction water from the water washing tower is sent to the azeotropic distillation tower 8 for recycling and reuse, and the C4 after water separation is sent to the liquefied gas storage tank in the tank area; Step 4, acetic acid, SBA and water are separated by azeotropic distillation. The azeotropic distillation tower 8 uses water as an azeotropic agent. Through azeotropic distillation, acetic acid and carbon twelve are separated from SBA and carbon eight olefins. The bottom materials of the decarbonization tower 4 and the decarbonization tower 6 enter the azeotropic distillation tower 8 at the same time. The SBA, carbon eight, water, etc. evaporated from the top of the tower are condensed and cooled and then separated. The aqueous phase is pumped in two ways: one part is refluxed and the other part is pumped into the carbon four water washing tower 7; the ester phase is crude ester, which is pumped out in two ways: one part is refluxed and the other part is pumped into the ester product tower 9. The crude acetic acid at the bottom of the tower is sent to the acetic acid refining tower 10 for treatment; Step 5, SBA product separation, crude ester is sent from the azeotropic distillation tower 8 to the ester product tower, carbon eight and water light fractions are evaporated from the top of the tower, condensed and cooled to separate, the water phase is heated by a steam generator and then returned to the ester product tower 9 as stripping steam, the light fraction is pressurized by the ester product tower reflux pump 9022 and then divided into two paths: one part is refluxed, and the other part is sent to the tank area, SBA is extracted from the bottom of the tower, and after heat exchange and cooling, it is sent to the SBA tank area; Step 6: acetic acid refining and recovery. The crude acetic acid at the bottom of the azeotropic distillation tower 8 contains high-boiling substances such as carbon dodecene. In order to avoid the reduction of the activity and life of the catalyst caused by metal cations, the crude acetic acid needs to pass through the acetic acid refining tower 10. After removing the high-boiling substances and metal ions from the bottom of the tower, refined acetic acid is extracted from the top of the tower. The crude acetic acid from the bottom of the azeotropic distillation tower 8 is pumped into the acetic acid refining tower 10, and the acetic acid is evaporated from the top of the tower. After condensation and cooling, it is pumped out by the acetic acid refining tower reflux pump 1004, a part of which is used for reflux, and a part of which is fed to the acetic acid feed pump 304 as esterification feed; The amount of high-boiling substances at the bottom of the tower is very small, and the operation is carried out in an intermittent manner. When the acetic acid content drops to the required level, it is cooled by the heavy fraction cooler, and then pumped out by the heavy material alkali washing feed pump, mixed with the water pumped out by the heavy material alkali washing circulation pump, washed, and then enters the heavy material alkali washing stratification tank 1011 for liquid stratification. After separation, it is pumped to the tank area by the heavy material delivery pump 1013. When the alkali solution concentration is too low to meet the requirements, fresh alkali solution is replaced.

[0023] It also has a hot water circulation part and an exhaust gas washing part. For the specific process, please refer to Fig. 9 As shown, The esterification reaction is an exothermic reaction. In order to ensure that the reaction in the shell-and-tube reactor is close to a constant temperature reaction, circulating hot water is introduced into the shell side to obtain heat. By controlling the temperature and flow of the hot water, a constant temperature reaction is achieved. This renovation plans to add two sets of hot water systems to control the primary reaction and the secondary reaction respectively. Water is pumped out from the hot water storage tank through a hot water circulation pump and sent to the shell side of the esterification reactor. After taking heat, it is sent to the hot water cooler and returned to the hot water storage tank after cooling. The exhaust gas from each device is washed with alkali in the exhaust gas washing tank to remove the residual acetic acid, ester and other corrosive media, and then discharged to the flare pipe network; The catalyst used in the reactor is a strong acid cation exchange resin catalyst, with an annual usage of about 50 tons (wet basis), while the raw material product varieties of this application remain unchanged and can rely on existing analytical and testing facilities.

[0024] The present application changes the original four series-connected esterification reactors into two-stage esterification, which deepens the esterification reaction depth and greatly improves the production capacity of sec-butyl acetate; the catalyst has high activity and good stability, and the reaction part uses circulating hot water for heat extraction, which has low operating costs; and a low-temperature hot water system is added, which greatly reduces the steam and circulating water consumption and greatly reduces the energy consumption of the device; At the same time, some of the newly added and updated low-pressure heat exchangers in this application use plate heat exchangers, which greatly saves floor space and investment costs, and uses solid acid catalysts, which are non-toxic and harmless, and are friendly to the production environment.

[0025] See also Figure 2-8 As shown, according to the above embodiment, a preparation device of the preparation process of sec-butyl acetate will also be provided, including a main pipe 1, a deisobutanizer 2, a first esterification reactor 3, a reverse mixer 301, a reverse decarbonization four tower 4, a second esterification reactor 5, a second reverse mixer 403, a decarbonization four tower 6, a carbon four water washing tower 7, an azeotropic distillation tower 8, an ester product tower 9, a steam generator 903, an acetic acid refining tower 10, an acetic acid deweighting tower reflux tank 1003, a heavy material alkali washing stratification tank 1011, a heavy material buffer tank 1012, a tail gas alkali washing tank and a waste oil storage tank; The main pipe 1 is connected to the feed port of the deisobutanizer 2. The top of the deisobutanizer 2 is provided with an isobutane tower top cooler 201 and an isobutane tower reflux tank 202 and connected by pipelines. The discharge port of the isobutane tower reflux tank 202 is connected to an isobutane tower reflux pump 203. The pump outlet of the isobutane tower reflux pump 203 is respectively connected to the top of the deisobutanizer 2 and the isobutane tank area through pipelines. The bottom of the deisobutanizer 2 is connected to the C4 tank area, the first reverse mixer 301 and the second reverse mixer 403 in series and parallel form through the isobutane tower bottom pump 204. The inlet pipeline of the first reverse mixer 301 is connected to the first reverse acetic acid preheating The outlet of the first anti-C4 preheater 302 and the first anti-C4 preheater 303, the inlet of the first anti-acetic acid preheater 302 is connected in parallel with the second anti-mixer 403 and the acetic acid feed pump 304 by a pipeline, the pump inlet of the acetic acid feed pump 304 is connected to the reflux tank of the acetic acid deweighting tower 10 through a pipeline, the first anti-C4 preheater 303 is connected in series with a coalescer 306 and a C4 filter 305 by a pipeline, the main pipe 1 and the bottom of the deisobutanizer 2 are connected to the C4 filter 305 through a pipeline, the outlet pipeline of the first anti-mixer 301 is connected to the first esterification reactor 3, and the discharge pipeline of the first esterification reactor 3 is connected to the feed port of the first anti-decarbonization tower 4 through a pipeline; The top of the first reverse decarbonization tower 4 is connected to the first reverse decarbonization tower top condenser 401 and the first reverse decarbonization tower top reflux tank 402 in sequence by pipelines. The first reverse decarbonization tower top reflux tank 402 is respectively connected to the inlet of the first reverse decarbonization tower reflux pump 4021 and the second reverse decarbonization tower feed pump 4022 through two pipelines. The outlet of the first reverse decarbonization tower reflux pump 4021 is respectively connected to the top of the first reverse decarbonization tower 4 and the inlet pipeline of the second reverse mixer 403 through pipelines. The bottom of the first reverse decarbonization tower 4 is connected to the first reverse decarbonization tower 4 through pipelines. The azeotropic distillation tower 8 is connected to the pipeline network respectively, the second reverse C4 feed pump 4022 is connected to the inlet pipeline of the second reverse mixer 403 through a pipeline and is connected in parallel with the pipeline connected to the C4 water washing tower 7, the inlet pipeline of the second reverse mixer 403 is connected in parallel with the pump outlet pipeline of the acetic acid feed pump 304 and the isobutane bottom pump 204, the outlet of the second reverse mixer 403 is connected to the second esterification reactor 5 through the second reverse feed heater 4031, and the discharge pipeline of the second esterification reactor 5 is connected to the feed port of the decarbonization tower 6; The top of the decarbonization tower 6 is connected to the decarbonization tower top condenser 601 and the decarbonization tower top reflux tank 602 in sequence by pipelines, the outlet of the decarbonization tower top reflux tank 602 is connected to the decarbonization tower reflux pump 6021, the decarbonization tower reflux pump 6021 is respectively connected to the top of the decarbonization tower 6 and the feed inlet of the carbon four water washing tower 7 through pipelines, the bottom of the decarbonization tower 6 is respectively connected to the azeotropic distillation tower 8 and the pipeline network through pipelines, the top of the carbon four water washing tower 7 is connected to the water-washed carbon four buffer tank 701 by pipelines, the outlet of the water-washed carbon four buffer tank 701 is connected to the carbon four delivery pump 702, the pump outlet of the carbon four delivery pump 702 is connected to the tank area liquefied gas storage tank through a pipeline, and the bottom of the carbon four water washing tower 7 is connected to the azeotropic distillation tower 8 through a pneumatic regulating valve; The top of the azeotropic distillation tower 8 is connected to an azeotropic distillation tower top condenser 801 and an azeotropic distillation tower top stratification tank 802 by pipelines, the azeotropic distillation tower top stratification tank 802 is respectively connected to a stratified water phase delivery pump 8021 and a stratified ester phase delivery pump 8022, the stratified water phase delivery pump 8021 is respectively connected to a C4 water washing tower 7, a waste oil storage tank and the top of the azeotropic distillation tower 8 through pipelines, the stratified ester phase delivery pump 8022 is respectively connected to a feed heat exchanger of an ester product tower 9 and the top of the azeotropic distillation tower 8 through pipelines, the bottom of the azeotropic distillation tower 8 is respectively connected to a pipe network and an azeotropic distillation tower bottom delivery pump 803, the azeotropic distillation tower bottom delivery pump 803 is connected to an acetic acid refining tower 10, and the tower tray of the azeotropic distillation tower 8 is a high-efficiency floating valve tower tray; The top of the ester product tower 9 is connected to an ester product tower condenser 901 and an ester product reflux tank 902 by a pipeline, the exhaust port of the ester product reflux tank 902 is connected to the tail gas alkali washing tank, the ester product reflux tank 902 is respectively connected to the pump inlet of the ester tower reflux tank water delivery pump 9021 and the ester product tower reflux pump 9022, the pump outlet of the ester tower reflux tank water delivery pump 9021 is respectively connected to the steam generator 903 and the feed inlet pipeline of the azeotropic distillation tower top layering tank 802, and the pump outlet of the ester product tower reflux pump 9022 is respectively connected to the tank area and the top of the ester product tower 9; The top of the acetic acid refining tower 10 is connected in series with an acetic acid refining tower low-temperature hot water heat exchanger 1001, an acetic acid refining tower condenser 1002 and an acetic acid deweighting tower reflux tank 1003 by pipelines. The exhaust port of the acetic acid deweighting tower reflux tank 1003 is connected to the tail gas alkali washing tank, and the acetic acid deweighting tower reflux tank 1003 is connected to the top of the acetic acid refining tower 10 through an acetic acid refining tower reflux pump 1004. The bottom end of the acetic acid refining tower 10 is connected to the pipeline network and the heavy material alkali washing stratification tank 1011 through pipelines, respectively. The heavy material alkali washing stratification tank 1011 is connected to the heavy material buffer tank 1012, and the heavy material buffer tank 1012 is connected to the heavy material tank area through a heavy material delivery pump 1013.

[0026] The main operating conditions after transformation are as follows: Fig.10 and Fig.11 shown.

[0027] According to the provisions of the Petrochemical Design Energy Consumption Calculation Standard (GB / T 50441-2016), The energy consumption of the device is calculated and the results are listed in the following table:

[0028] The production of sec-butyl acetate of this device is 9.375t / h, and the energy consumption per ton of sec-butyl acetate is 152.59 standard oil / ton.

[0029] The working principle of the present invention is: The etherified C4 raw material is sent to the deisobutanizer 2 through the main pipe 1. The deisobutane is cooled from the top of the tower and sent to the isobutane tower reflux tank 202. It is then sent to the tank area through the isobutane tower reflux pump 203. The concentrated C4 is sent to the first esterification reactor 3 through the isobutane tower bottom pump 204. The acetic acid raw material is pumped out from the reflux tank of the acetic acid refining tower 10 by a feed pump and sent to the acetic acid preheater to be heated to the preheating temperature. The C4 at the bottom of the deisobutanizer 2 is heated by the preheater and mixed with acetic acid to enter the first esterification reactor 3 for esterification reaction. All the reaction products enter the first decarbonization tower 4 for heavy fraction separation. The heavy fraction is separated from the bottom of the tower and enters the azeotropic distillation tower 8. The unreacted C4 comes out from the top of the tower and is condensed to the secondary esterification reaction. The unreacted C4 is sent to the secondary esterification by a pump under pressure, mixed with acetic acid from the reflux tank of the acetic acid refining tower 10 and preheated, and then sent to the second esterification reactor 5 for esterification reaction. All the reaction products enter the decarbonization tower 6 for heavy fraction separation. The top pressure of the decarbonization tower 6 adopts a thermal bypass control process. The C4 liquid condensed at the top of the tower is pumped out by the decarbonization tower reflux pump 6021, part of which is sent to the top of the tower for reflux, and part of which is sent to the C4 water washing tower 7. The acid-containing extraction water of the water washing tower is sent to the azeotropic distillation tower 8 for recovery and reuse. The C4 after water separation is sent to the liquefied gas storage tank in the tank area; The azeotropic distillation tower 8 uses water as an azeotropic agent to separate acetic acid and carbon twelve from SBA and carbon eight olefins through azeotropic distillation. The bottom materials of the decarbonization tower 4 and the decarbonization tower 6 enter the azeotropic distillation tower 8 at the same time. The SBA, carbon eight, water, etc. evaporated from the top of the tower are condensed and cooled and then separated. The water phase is pumped through two routes: one part is refluxed and the other part is pumped into the carbon four water washing tower 7; the ester phase is crude ester, which is pumped out through two routes: one part is refluxed and the other part is pumped into the ester product tower 9. The crude acetic acid at the bottom of the tower is sent to the acetic acid refining tower 10 for treatment; The crude ester is sent from the azeotropic distillation tower 8 to the ester product tower, and the carbon eight and water light fractions are evaporated from the top of the tower, condensed, cooled and separated, and the water phase is heated by the steam generator and then returned to the ester product tower 9 as stripping steam. The light fraction is pressurized by the ester product tower reflux pump 9022 and then divided into two paths: one part is refluxed and the other part is sent to the tank area. SBA is extracted from the bottom of the tower, and after heat exchange and cooling, it is sent to the SBA tank area. The crude acetic acid from the bottom of the azeotropic distillation tower 8 is pumped into the acetic acid refining tower 10, and the acetic acid is evaporated from the top of the tower, condensed and cooled, and then pumped out by the acetic acid refining tower reflux pump 1004, part of which is used for reflux, and part of which is fed to the acetic acid feed pump 304 for esterification. The amount of high-boiling substances at the bottom of the tower is very small, and the operation is carried out in an intermittent manner. When the acetic acid content drops to the required level, it is cooled in the heavy fraction cooler and then pumped out by the heavy material alkali washing feed pump, mixed with the water pumped out by the heavy material alkali washing circulation pump, washed, and then enter the heavy material alkali washing stratification tank 1011 for liquid stratification. After separation, it is pumped to the tank area by the heavy material delivery pump 1013.

[0030] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contributions as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A process for preparing sec-butyl acetate, characterized in that , including the following steps: Step 1: Concentrate the raw material. The etherified C4 raw material is sent to the deisobutanizer (2) through the main pipe (1). The deisobutanizer is cooled from the top of the tower and sent to the isobutane tower reflux tank (202). It is then transported to the tank area through the isobutane tower reflux pump (203). The concentrated C4 is sent to the first esterification reactor (3) through the isobutane tower bottom pump (204). Step 2, primary esterification reaction, the acetic acid raw material is pumped out from the reflux tank of the acetic acid refining tower (10) by a feed pump and sent to the acetic acid preheater to be heated to the preheating temperature, the C4 at the bottom of the deisobutanizer (2) is heated in the preheater and mixed with acetic acid to enter the first esterification reactor (3) for esterification reaction, and all the reaction products enter the first decarbonization tower (4) for separation of heavy fractions, and the heavy fractions separated from the bottom of the tower enter the azeotropic distillation tower (8), and the undecarbonated C4 is condensed from the top of the tower to the secondary esterification reaction; Step 3, secondary esterification reaction, the unreacted C4 is sent to the secondary esterification through a pump under pressure, mixed with acetic acid from the reflux tank of the acetic acid refining tower (10) and preheated, and then sent to the second esterification reactor (5) for esterification reaction, and all the reaction products enter the decarbonization tower (6) for heavy fraction separation. The top pressure of the decarbonization tower (6) adopts a thermal bypass control process. The C4 liquid condensed at the top of the tower is pumped out through the decarbonization tower reflux pump (6021), a part of which is sent to the top of the tower as reflux, and a part of which is sent to the C4 water washing tower (7). The acid-containing extraction water of the water washing tower is sent to the azeotropic distillation tower (8) for recovery and reuse. The C4 after water separation is sent to the liquefied gas storage tank in the tank area; Step 4: azeotropic distillation separation of acetic acid, SBA and water. The azeotropic distillation tower (8) uses water as an azeotropic agent to separate acetic acid and C12 from SBA and C8 olefins through azeotropic distillation. The bottom materials of the decarbonization tower (4) and the decarbonization tower (6) enter the azeotropic distillation tower (8) at the same time. The SBA, C8, water, etc. evaporated from the top of the tower are condensed and cooled and then separated into layers. The aqueous phase is pumped through two routes: one part is refluxed and the other part is pumped into the C4 water washing tower (7). The ester phase is crude ester, which is pumped out through two routes: one part is refluxed and the other part is pumped into the ester product tower (9). The crude acetic acid at the bottom of the tower is sent to the acetic acid refining tower (10) for treatment. Step 5, SBA product separation, the crude ester is sent from the azeotropic distillation tower (8) to the ester product tower, the carbon eight and water light fractions are evaporated from the top of the tower, condensed and cooled to separate, the water phase is heated by a steam generator and then returned to the ester product tower (9) as stripping steam, the light fraction is pressurized by the ester product tower reflux pump (9022) and then divided into two paths: one part is refluxed and the other part is sent to the tank area, SBA is extracted from the bottom of the tower, and after heat exchange and cooling, it is sent to the SBA tank area; Step 6: acetic acid refining and recovery: crude acetic acid from the bottom of the azeotropic distillation tower (8) is pumped into the acetic acid refining tower (10); acetic acid is distilled from the top of the tower, condensed and cooled, and then pumped out by the acetic acid refining tower reflux pump (1004); part of it is used as reflux, and part of it is fed to the acetic acid feed pump (304) as esterification feed; The amount of high-boiling materials at the bottom of the tower is very small, and the tower is operated in an intermittent manner. When the acetic acid content is reduced to the required level, it is cooled in a heavy fraction cooler and then pumped out by a heavy material alkaline wash feed pump. It is mixed with water pumped out by a heavy material alkaline wash circulation pump for washing and then enters a heavy material alkaline wash stratification tank (1011) for liquid stratification. After separation, it is pumped to the tank area by a heavy material transfer pump (1013).

2. A process for preparing sec-butyl acetate according to claim 1, characterized in that: In the step 1, the deisobutanizer (2) is provided with 60 layers of trays, the bottom temperature is 70° C., the top temperature is 60° C., and the top pressure is 0.8 MPa.

3. A process for preparing sec-butyl acetate according to claim 1, characterized in that: In step 2, the first esterification reactor (3) is composed of two primary esterification sensors connected in parallel and then connected in series to a first pre-esterification reactor. The reaction temperature is set at 70° C. and the reaction pressure is 1.4 MPa. The temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to a constant temperature. The reaction products are mainly: SBA, C8, C12, acetic acid and unreacted C4; The first decarbonization tower (4) separates the undecarbonized carbon four from heavy fractions such as acetic acid, SBA, carbon eight olefins, and carbon twelve olefins.

4. A process for preparing sec-butyl acetate according to claim 1, characterized in that: In step 3, the second esterification reactor (5) is composed of two secondary esterification reactors connected in parallel and then connected in series with a second pre-esterification reactor. The temperature and flow rate of the shell-side circulating hot water are controlled to ensure that the reaction is close to constant temperature. The reaction products mainly include: SBA, C8, C12, acetic acid and unreacted C4; The decarbonization tower (6) separates the unreacted C4 from heavy fractions such as acetic acid, SBA, C8 olefins, and C12 olefins; Furthermore, the C4 water washing tower (7) uses the water phase from the azeotropic distillation tower (8) as an extractant to extract the trace amount of acetic acid in the C4 with water to meet the requirements of liquefied gas quality and corrosion of the transmission pipeline and equipment.

5. A process for preparing sec-butyl acetate according to claim 1, characterized in that: In step 6, the crude acetic acid at the bottom of the azeotropic distillation tower (8) contains high-boiling products such as dodecene. In order to avoid the reduction of the activity and life of the catalyst caused by metal cations, the crude acetic acid needs to pass through an acetic acid refining tower (10) to remove high-boiling products and metal ions from the bottom of the tower and then extract refined acetic acid from the top of the tower.

6. A preparation device according to any one of claims 1 to 5 for preparing sec-butyl acetate, characterized in that: It comprises a main pipe (1), a deisobutane tower (2), a first esterification reactor (3), a first reverse mixer (301), a first reverse decarbonization tower (4), a second esterification reactor (5), a second reverse mixer (403), a decarbonization tower (6), a carbon four water washing tower (7), an azeotropic distillation tower (8), an ester product tower (9), a steam generator (903), an acetic acid refining tower (10), an acetic acid deheaving tower reflux tank (1003), a heavy material alkali washing stratification tank (1011), a heavy material buffer tank (1012), an exhaust gas alkali washing tank and a waste oil storage tank; The main pipe (1) is connected to the feed inlet of the deisobutanizer (2); the top of the deisobutanizer (2) is provided with an isobutane tower top cooler (201) and an isobutane tower reflux tank (202) and connected via pipelines; the discharge port of the isobutane tower reflux tank (202) is connected to an isobutane tower reflux pump (203); the pump outlet of the isobutane tower reflux pump (203) is connected to the top of the deisobutanizer (2) and the isobutane tank area via pipelines; the bottom of the deisobutanizer (2) is connected to the C4 tank area, the first reverse mixer (301) and the second reverse mixer (403) in series and parallel via the isobutane tower bottom pump (204); the inlet pipeline of the first reverse mixer (301) is connected to the first reverse acetic acid preheater (3 02) and the outlet of a first reverse carbon four preheater (303); the inlet of the first reverse acetic acid preheater (302) is connected in parallel with the second reverse mixer (403) and the acetic acid feed pump (304) by a pipeline; the pump inlet of the acetic acid feed pump (304) is connected to the reflux tank of the acetic acid deweighting tower (10) by a pipeline; the first reverse carbon four preheater (303) is connected in series with a coalescer (306) and a carbon four filter (305) by a pipeline; the main pipe (1) and the bottom of the deisobutanizer (2) are connected to the carbon four filter (305) by pipelines; the outlet pipeline of the first reverse mixer (301) is connected to the first esterification reactor (3); and the discharge pipeline of the first esterification reactor (3) is connected to the feed port of the first reverse decarbonization four tower (4) by a pipeline.

7. The preparation device of a preparation process for sec-butyl acetate according to claim 6, characterized in that: The top of the first reverse decarbonization tower (4) is connected to the first reverse decarbonization tower top condenser (401) and the first reverse decarbonization tower top reflux tank (402) in sequence by pipelines; the first reverse decarbonization tower top reflux tank (402) is respectively connected to the inlet of the first reverse decarbonization tower reflux pump (4021) and the second reverse decarbonization tower feed pump (4022) through two pipelines; the outlet of the first reverse decarbonization tower reflux pump (4021) is respectively connected to the top of the first reverse decarbonization tower (4) and the inlet pipeline of the second reverse mixer (403) through pipelines; the bottom of the first reverse decarbonization tower (4) is respectively connected to the first reverse decarbonization tower (4) through pipelines. The azeotropic distillation tower (8) is connected to a pipeline network, the second reactor C4 feed pump (4022) is connected to the inlet pipeline of the second reactor mixer (403) through a pipeline and is connected in parallel with a pipeline connected to the C4 water washing tower (7), the inlet pipeline of the second reactor mixer (403) is connected in parallel with an acetic acid feed pump (304) and an isobutane tower bottom pump (204) pump outlet pipeline, the outlet of the second reactor mixer (403) is connected to the second esterification reactor (5) through a second reactor feed heater (4031), and the discharge pipeline of the second esterification reactor (5) is connected to the feed port of the decarbonization tower (6).

8. The preparation device of a preparation process for sec-butyl acetate according to claim 6, characterized in that: The top of the decarbonization tower (6) is connected to the decarbonization tower top condenser (601) and the decarbonization tower top reflux tank (602) in sequence by pipelines. The outlet of the decarbonization tower top reflux tank (602) is connected to the decarbonization tower reflux pump (6021). The decarbonization tower reflux pump (6021) is connected to the top of the decarbonization tower (6) and the feed inlet of the carbon four water washing tower (7) through pipelines. The bottom of the decarbonization tower (6) is connected to the decarbonization tower top condenser (601) and the decarbonization tower top reflux tank (602) through pipelines. The pipelines are respectively connected to the azeotropic distillation tower (8) and the pipeline network; the top of the C4 water washing tower (7) is connected to the water-washed C4 buffer tank (701) by a pipeline; the outlet of the water-washed C4 buffer tank (701) is connected to the C4 delivery pump (702); the pump outlet of the C4 delivery pump (702) is connected to the liquefied gas storage tank in the tank area through a pipeline; and the bottom of the C4 water washing tower (7) is connected to the azeotropic distillation tower (8) through a pneumatic regulating valve.

9. The preparation device of a preparation process for sec-butyl acetate according to claim 6, characterized in that: The top of the azeotropic distillation tower (8) is connected to an azeotropic distillation tower top condenser (801) and an azeotropic distillation tower top stratification tank (802) by pipelines. The azeotropic distillation tower top stratification tank (802) is respectively connected to a stratified water phase delivery pump (8021) and a stratified ester phase delivery pump (8022). The stratified water phase delivery pump (8021) is respectively connected to a C4 water washing tower (7), a waste oil storage tank and the top of the azeotropic distillation tower (8) by pipelines. The stratified ester phase delivery pump (8022) is respectively connected to a feed heat exchanger of an ester product tower (9) and the top of the azeotropic distillation tower (8) by pipelines. The bottom of the azeotropic distillation tower (8) is respectively connected to a pipe network and an azeotropic distillation tower bottom delivery pump (803). The azeotropic distillation tower bottom delivery pump (803) is connected to an acetic acid refining tower (10). The tower tray of the azeotropic distillation tower (8) is a high-efficiency floating valve tower tray. The top of the ester product tower (9) is connected to an ester product tower condenser (901) and an ester product reflux tank (902) by pipelines; the exhaust port of the ester product reflux tank (902) is connected to a tail gas alkali washing tank; the ester product reflux tank (902) is respectively connected to an ester tower reflux tank water delivery pump (9021) and a pump inlet of an ester product tower reflux pump (9022); the pump outlet of the ester tower reflux tank water delivery pump (9021) is respectively connected to a steam generator (903) and a feed inlet pipeline of an azeotropic distillation tower top layering tank (802); and the pump outlet of the ester product tower reflux pump (9022) is respectively connected to a tank area and the top of the ester product tower (9).

10. The preparation device of a preparation process of sec-butyl acetate according to claim 6, characterized in that: The top of the acetic acid refining tower (10) is connected in series via a pipeline to an acetic acid refining tower low-temperature hot water heat exchanger (1001), an acetic acid refining tower condenser (1002) and an acetic acid de-weighting tower reflux tank (1003); the exhaust port of the acetic acid de-weighting tower reflux tank (1003) is connected to an exhaust gas alkali washing tank, and the acetic acid de-weighting tower reflux tank (1003) is connected to the top of the acetic acid refining tower (10) via an acetic acid refining tower reflux pump (1004); the bottom of the acetic acid refining tower (10) is connected to a pipeline network and a heavy matter alkali washing and stratification tank (1011) via pipelines, the heavy matter alkali washing and stratification tank (1011) is connected to a heavy matter buffer tank (1012), and the heavy matter buffer tank (1012) is connected to a heavy matter tank area via a heavy matter delivery pump (1013).

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