Energy-saving device and method for producing methyl tert-butyl ether and 1-butene

Abstract

The invention belongs to the technical field of chemical separation and refining, and discloses an energy-saving device and method for producing methyl tert-butyl ether and 1-butene. Fine separation is performed at the top of the light component pre-removal tower, and heat recovery is performed while isobutane is recovered. And the gas phase at the top of the light component pre-removal tower is extracted as a heat source of the light component removal tower and the heavy component removal tower reboiler, so that the public engineering consumption of the light component removal tower and the heavy component removal tower reboiler is replaced. Meanwhile, the MTBE removal tower feeding vaporizer and the catalytic rectifying tower feeding vaporizer which are additionally arranged are heated by using low-temperature hot water, so that more than half of steam is saved. According to the process, the steam energy consumption is totally saved by about 84.15%, the treatment capacity of a subsequent device is reduced by 19.8%, and the energy consumption is totally reduced by 24.51%. Under the condition of ensuring the product index and the yield, the purpose of saving the cost is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical separation and refining, and in particular to an energy-saving device and method for producing methyl tert-butyl ether and 1-butene. Background Art

[0002] With the development of domestic refining technology, my country's annual C4 production capacity continues to increase. This part of C4 is mainly composed of isobutane, isobutylene, normal butane, normal butene and 2-butene, and also contains a small amount of propane, propylene, 1,3-butadiene, etc. Usually, the C4 raw material and methanol are mixed in the raw material purification tank 1 and then cooled to 40°C by the reaction feed cooler 2 before entering the etherification reactor 3 for etherification reaction. The etherification reactor 3 is an external circulation fixed bed reactor. After the reaction of the etherification reactor 3, part of the material is recycled to the inlet of the etherification reactor 3, mixed with fresh materials and then enters the etherification reactor 3, and the other part of the reacted material enters the middle part of the catalytic distillation tower 4. The catalytic distillation tower 4 has a methanol replenishment inlet for replenishing the methanol required for the deep etherification reaction. Most of the MTBE is removed from the reaction material in the catalytic distillation tower 4, and the isobutylene in the unreacted C4 is further converted into MTBE so that the content meets the requirements of butene-1 separation. The MTBE discharged from the bottom of the tower is sent to the outside of the boundary area, and the remaining C4 at the top of the tower enters the extraction tower 5. The remaining C4 is washed with residual methanol in the extraction tower 5, and the methanol-water solution enters the methanol recovery tower 6 to recover methanol. The washed C4 is then separated by the 1-butene separation unit, namely the light removal tower 7 and the heavy removal tower 8. The isobutane product is obtained at the top of the light removal tower 7, and the 1-butene product and the normal butane / 2-butene product are obtained in the heavy removal tower 8. However, the current process can only produce qualified MTBE products, and the purity of the subsequent 1-butene product cannot meet the requirements. In addition, the steam usage is large, which makes the production cost remain high.

[0003] Methyl tert-butyl ether (MTBE) is widely used worldwide as a gasoline additive. 1-Butene belongs to C4 olefins and is an important monomer for producing polymers. With the transformation of energy and the demand for production, the demand for 1-butene is increasing. In order to increase economic benefits, it is necessary to produce 1-butene through other feasible ways. After the mixed C4 is etherified to remove isobutylene, the etherified C4 obtained contains a large amount of 1-butene. Therefore, how to extract 1-butene from the etherified C4 is a hot issue for people to study. At present, most of 1-butene is mainly obtained by extractive distillation and distillation separation. It mainly includes two parts: the light removal tower and the heavy removal tower. The light removal tower removes the low-boiling C3, isobutane and azeotrope with water in the C4. The bottom product is then removed by the heavy removal tower to remove the high-boiling n-butane and 2-butene, and the top of the tower obtains 1-butene with a mass fraction greater than 99%. Although the process is simple, it requires a large number of plates and a large reflux ratio. Both towers require heat sources and have high energy consumption. In addition, there is an extraction distillation process to separate 1-butene. Taking Japan's Ruiong extraction process as an example, this process uses DMF as the extraction agent and can separate 1-butene products with a purity of 99%. However, the process is long, the energy consumption is high, and the extraction agent DMF is easily decomposed under high temperature conditions.

[0004] Patent CN104926587A discloses an energy-saving process for separating and purifying 1-butene. After the etherified C4 mixture from the etherification reactor is selectively hydrogenated, ultra-precision distillation separation technology is used to achieve heat integration of the deisobutanizer and the 1-butene refining tower. However, the deisobutanizer still needs to use low-pressure steam for heating. At the same time, the energy consumption of using a deweighting tower to separate 1-butene is relatively high. From the perspective of separation thermodynamics, there is still room for energy-saving optimization.

[0005] Patent CN110759801B discloses a method for preparing diisobutylene by mixing C4, wherein the C4 raw material undergoes polymerization reaction in the presence of a catalyst and an inhibitor, and finally diisobutylene is separated and the inhibitor is recovered by distillation after the polymerization reaction. Although this process improves the isobutylene conversion rate, it is still not as high as the conversion rate when synthesizing MTBE, which causes certain difficulties in the subsequent separation of isobutylene, and the inhibitor needs to be recovered by distillation, which increases the consumption of public works.

[0006] Patent CN115010571B discloses a method for separating isobutane and 1-butene by C4 after etherification to solve the problems of poor separation effect and high energy consumption. However, its working pressure and working temperature are relatively high, indicating that it has not fully optimized the energy consumption, nor has it been thermally combined with other equipment to reduce energy consumption. In addition, the purity of the recovered 1-butene is relatively low, which does not meet the product requirements.

[0007] The above patent and the original process are at a high working pressure and cannot fully recycle heat, resulting in a large consumption of public works, mainly because the catalytic distillation tower and the lightness removal tower have a large processing capacity, resulting in a high overall energy consumption of the process; and the MTBE and 1-butene products produced by the original process are of low purity and can no longer meet the current product quality requirements. Therefore, a new process is needed that can operate with low power consumption and produce high-purity MTBE and 1-butene products at the same time. Summary of the invention

[0008] In view of this, in order to reduce the processing volume of the etherification device and the subsequent separation device, reduce the energy consumption of the catalytic distillation tower and the lightness removal tower and improve the purity of MTBE and 1-butene products, the present invention provides an energy-saving device and method for producing methyl tert-butyl ether and 1-butene, which realizes the production of high-purity MTBE and 1-butene products with low power consumption through process transformation and heat combination.

[0009] The technical scheme adopted by the present invention is: an energy-saving device for producing methyl tert-butyl ether and 1-butene, comprising a feed preheater A1, a pre-light removal tower A2, a pre-light removal tower reboiler A3, a raw material purification tank A4, a reaction feed cooler A5, an etherification reactor A6, a de-MTBE tower feed vaporizer A7, a de-MTBE tower A8, a de-MTBE tower condenser A9, a de-MTBE tower reboiler A10, a catalytic distillation tower feed heat exchanger A11, a catalytic distillation tower feed Vaporizer A12, catalytic distillation tower A13, catalytic distillation tower condenser A14, catalytic distillation tower reboiler A15, extraction tower feed cooler A16, extraction tower A17, methanol recovery tower A18, methanol recovery tower condenser A19, methanol recovery tower reboiler A20, lightness removal tower A21, lightness removal tower condenser A22, pre-lightness removal tower / lightness removal tower heat exchanger A23, heavyness removal tower A24, heavyness removal tower condenser A25, pre-lightness removal tower / weight removal tower heat exchanger A26;

[0010] The first inlet of feed preheater A1 inputs raw materials;

[0011] The first outlet of the feed preheater A1 is connected to the feed inlet of the bottom of the pre-light removal tower A2; the second outlet of the feed preheater A1 is connected to the first inlet of the raw material purification tank A4;

[0012] The bottom outlet of the pre-light-removal tower A2 is connected to the pre-light-removal tower reboiler A3 and the second inlet of the feed preheater A1 respectively; the pre-light-removal tower reboiler A3 is back-connected to the bottom inlet of the pre-light-removal tower A2; the top outlet of the pre-light-removal tower A2 is connected to the first inlet of the pre-light-removal tower / light-removal tower heat exchanger A23 and the first inlet of the pre-light-removal tower / heavy-removal tower heat exchanger A26 respectively through a three-way valve;

[0013] The methanol feed is connected to the second inlet of the raw material purification tank A4; the outlet of the raw material purification tank A4 is connected to the inlet of the etherification reactor A6 through the reaction feed cooler A5; the outlet of the etherification reactor A6 is respectively connected to the inlet of the reaction feed cooler A5, the inlet of the MTBE removal tower vaporizer A7, the inlet of the distillation tower feed vaporizer A12, and the inlet of the extraction tower feed cooler A16 through a three-way valve; the outlet of the MTBE removal tower vaporizer A7 is connected to the inlet of the MTBE removal tower A8; the top outlet of the MTBE removal tower A8 is connected to the inlet of the MTBE removal tower condenser A9; the outlets of the MTBE removal tower condenser A9 are respectively connected The top inlet of the MTBE removal tower A8 and the first inlet of the catalytic distillation tower feed heat exchanger A11; the first outlet of the catalytic distillation tower feed heat exchanger A11 is respectively connected to the inlet of the catalytic distillation tower feed vaporizer A12 and the inlet of the extraction tower feed cooler A16 through a three-way valve; the bottom outlet of the MTBE removal tower A8 is respectively connected to the MTBE removal tower reboiler A10 and the second inlet of the catalytic distillation tower feed heat exchanger A11; the MTBE removal tower reboiler A10 is back-connected to the bottom inlet of the MTBE removal tower A8; the second outlet of the catalytic distillation tower feed heat exchanger A11 is connected to the high-purity MTBE product outlet;

[0014] The outlet of the catalytic distillation tower feed vaporizer A12 is connected to the first inlet of the catalytic distillation tower A13; the methanol feed is connected to the second inlet of the catalytic distillation tower A13; the top outlet of the catalytic distillation tower A13 is connected to the inlet of the extraction tower feed cooler A16 through the catalytic distillation tower condenser A14; the catalytic distillation tower condenser A14 is back-connected to the top inlet of the catalytic distillation tower A13; the bottom outlet of the catalytic distillation tower A13 is respectively connected to the catalytic distillation tower reboiler A15 and the low-purity MTBE product outlet; the catalytic distillation tower reboiler A15 is back-connected to the bottom inlet of the catalytic distillation tower A13;

[0015] The outlet of the extraction tower feed cooler A16 is connected to the lower inlet of the extraction tower A17; the water feed is connected to the upper inlet of the extraction tower A17; the top outlet of the extraction tower A17 is connected to the inlet of the light removal tower A21; the bottom outlet of the extraction tower A17 is connected to the inlet of the methanol recovery tower A18; the top outlet of the methanol recovery tower A18 is connected to the methanol product outlet through the methanol recovery tower condenser A19; the methanol recovery tower condenser A19 is back connected to the inlet of the methanol recovery tower A18; the bottom outlet of the methanol recovery tower A18 is respectively connected to the methanol recovery tower reboiler A20 and the water outlet; the methanol recovery tower reboiler A20 is back connected to the methanol recovery The bottom inlet of tower A18; the top outlet of lightness removal tower A21 is connected to the isobutane product outlet through the lightness removal tower condenser A22; the lightness removal tower condenser A22 is back-connected to the top inlet of lightness removal tower A21; the bottom outlet of lightness removal tower A21 is back-connected to the bottom inlet of lightness removal tower A21 through the inlet of pre-lightness removal tower / lightness removal tower heat exchanger A23; the first outlet of pre-lightness removal tower / lightness removal tower heat exchanger A23 and the first outlet of pre-lightness removal tower / weight removal tower heat exchanger A26 are connected to the top inlet of pre-lightness removal tower A2 and the isobutane product outlet respectively after being combined; the second outlet of pre-lightness removal tower / lightness removal tower heat exchanger A23 is connected to the inlet of weight removal tower A24;

[0016] The top outlet of the deweighting tower A24 is connected to the 1-butene product outlet through the deweighting tower condenser A25, and the deweighting tower condenser A25 is back-connected to the top inlet of the deweighting tower A24; the bottom outlet of the deweighting tower A24 is respectively connected to the second inlet of the pre-light-removing tower / weight-removing tower heat exchanger bA26 and the n-butane-rich / 2-butene product outlet; the outlet of the pre-light-removing tower / weight-removing tower heat exchanger bA26 is connected to the bottom inlet of the deweighting tower A24.

[0017] An energy-saving method for producing methyl tert-butyl ether and 1-butene is implemented based on the device, and the process is as follows:

[0018] First, the raw material A is heat exchanged with the bottom product of the pre-light-removing tower A2 by the feed preheater A1, and then enters the pre-light-removing tower A2 for distillation operation to obtain the isobutane gas phase B produced at the top of the tower and the isobutane-removing raw material C at the bottom of the tower; the isobutane gas phase produced B is divided into two streams, one is isobutane 1# gas D, which enters the pre-light-removing tower / light-removing tower heat exchanger A23 for condensation, and the other is isobutane 2# gas E, which enters the pre-light-removing tower / heavy-removing tower heat exchanger A26 for condensation; after the two condensed streams are combined, a part of the stream is used as the return The first stream enters the top of the pre-light-removing tower A2, and the other stream is combined with the liquid phase extracted from the top of the light-removing tower A21 to be extracted as the isobutane product F; the isobutane-removing raw material C is cooled by the feed preheater A1 and enters the raw material purification tank A4, mixed with the raw material methanol G in the raw material purification tank A4, and then cooled by the reaction feed cooler A5, and then enters the etherification reactor A6; the etherification reaction occurs in the etherification reactor A6, one stream re-enters the reaction feed cooler A5 as reflux, and the other stream is the preliminary etherification carbon four product I;

[0019] The preliminary etherified C4 product I is selected to enter the de-MTBE tower feed vaporizer A7 and / or the extraction tower feed cooler A16 according to the process requirements, and enters the de-MTBE tower feed vaporizer A7 for partial vaporization before entering the de-MTBE tower A8. The stream obtained at the bottom of the tower is divided into two streams, one of which is vaporized by the de-MTBE tower reboiler A10 and then enters the de-MTBE tower A8 bottom, and the other is cooled by the catalytic distillation tower feed heat exchanger A11 and extracted as a high-purity MTBE product K; the de-MTBE product J is obtained from the top of the de-MTBE tower A8 through the de-MTBE tower condenser A9, and is preheated by the catalytic distillation tower feed heat exchanger A11, and then selected to enter the catalytic distillation tower feed vaporizer A12 and / or the extraction tower feed cooler A16 according to the process requirements. or extraction tower feed cooler A16; after the MTBE-removed product J is partially vaporized in the catalytic distillation tower feed vaporizer A12, it enters the catalytic distillation tower A13 with the methanol raw material G; a low-purity MTBE product M is obtained at the bottom of the catalytic distillation tower A13; the etherified carbon four L at the top of the catalytic distillation tower A13 passes through the catalytic distillation tower condenser A14 and enters the extraction tower feed cooler A16, and enters the bottom inlet of the extraction tower A17 after cooling; the washing water N enters the top inlet of the extraction tower A17, and the methanol-removed etherified carbon four O is obtained at the top outlet of the extraction tower A17, and the methanol aqueous solution P is obtained at the bottom outlet of the extraction tower A17; the methanol aqueous solution P enters the methanol recovery tower A18, and methanol Q is obtained at the top of the tower, and water R is obtained at the bottom of the tower;

[0020] After removing methanol ether, C4 O enters light-removing tower A21, and isobutane product F is produced in the liquid phase at the top of the tower, and product T is produced at the bottom of the tower. Product T at the bottom of the light-removing tower enters heavy-removing tower A24; 1-butene product U is obtained at the top of heavy-removing tower A24, and n-butane / 2-butene-rich product V is obtained at the bottom of the tower.

[0021] The total concentration of propane, propylene, isobutane, n-butane, cis-2-butene and trans-2-butene in the raw material A is less than 60wt%, the concentration of isobutylene is less than 50wt%, the concentration of 1-butene is less than 50wt%, and the total concentration of the remaining components is less than 20wt%.

[0022] The process parameters are as follows: the number of theoretical plates of the pre-light-removal tower A2 is 60 to 180, the reflux ratio is 10 to 60, and the tower operating pressure is 0.7 to 1.4 MPa; the number of theoretical plates of the MTBE removal tower A8 is 10 to 180, and the tower operating pressure is 0.3 to 1.4 MPa; the number of theoretical plates of the catalytic distillation tower A13 is 10 to 180, the reflux ratio is 0.5 to 10, and the tower operating pressure is 0.5 to 1.4 MPa; the number of theoretical plates of the light-removal tower A22 is 10 to 180, the reflux ratio is 5 to 60, and the tower operating pressure is 0.5 to 0.8 MPa; the number of theoretical plates of the de-weighting tower A25 is 10 to 180, the reflux ratio is 5 to 60, and the tower operating pressure is 0.4 to 0.8 MPa;

[0023] The pre-delight tower A2 uses 70-180°C hot water as a heat source; the MTBE removal tower feed vaporizer A7 and the catalytic distillation tower feed vaporizer A12 use 70-180°C hot medium water as a heat source; the MTBE removal tower reboiler A10 and the catalytic distillation tower reboiler A15 use 0.1-5Mpa steam as a heat source.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the top of the pre-light-removal tower is finely separated, and heat is recovered while isobutane is recovered. The gas phase extracted from the top of the pre-light-removal tower is used as the heat source for the heat exchangers of the light-removal tower and the heavy-removal tower, replacing the public engineering consumption of the heat exchangers of the light-removal tower and the heavy-removal tower. At the same time, the newly added MTBE removal tower feed vaporizer and catalytic distillation tower feed vaporizer can be heated with low-temperature hot water, saving more than half of the steam. While ensuring the purity and recovery rate of MTBE products, isobutane products, 1-butene products, and 2-butene products, by taking the pre-light-removal method, part of the normal butane / 2-butene heavy components are extracted, which can reduce the processing capacity of all subsequent devices. At the same time, by adjusting the tower pressure of the pre-light-removal tower, the light-removal tower, and the post-heavy-removal tower, heat integration is achieved, and two vaporizers are added, which can greatly reduce the overall energy consumption of the device.

[0025] This process saves about 84.15% of steam energy consumption, reduces the processing capacity of subsequent devices by 19.8%, and reduces the overall energy consumption by 24.51%. While ensuring product indicators and yields, the purpose of cost saving is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the original process technology and equipment.

[0027] Figure 2 The present invention is a schematic diagram of an energy-saving process and device for producing methyl tert-butyl ether and 1-butene.

[0028] In the figure: In the figure: 1-raw material purification tank; 2-reaction feed cooler; 3-etherification reactor; 4-catalytic distillation tower; 5-extraction tower; 6-methanol recovery tower; 7-light removal tower; 8-heavy removal tower; A1-feed preheater; A2-pre-light removal tower; A3-pre-light removal tower reboiler; A4-raw material purification tank; A5-reaction feed cooler; A6-etherification reactor; A7-MTBE removal tower feed vaporizer; A8-MTBE removal tower; A9-MTBE removal tower condenser; A10-MTBE removal tower reboiler; A11-catalytic distillation tower feed heat exchanger; A12-catalytic distillation tower feed vaporizer; A13-catalytic distillation tower; A14-catalytic distillation tower condenser; A15-catalytic distillation tower reboiler; A16-extraction tower feed cooler; A17-extraction tower; A18-methanol recovery tower; A19-methanol recovery tower Condenser; A20-methanol recovery tower reboiler; A21-lightness removal tower; A22-lightness removal tower condenser; A23-pre-lightness removal tower / lightness removal tower heat exchanger; A24-heavy removal tower; A25-heavy removal tower condenser; A26-pre-lightness removal tower / heavy removal tower heat exchanger; A-raw material; B-isobutane gas phase extraction; C-isobutane removal raw material; D-isobutane 1# gas; E-isobutane 2# gas; F-isobutane product; G-raw material Feed methanol; H-C4-methanol mixed solution; I-preliminary etherification C4 product; J-MTBE-removed product; K-high-purity MTBE product; L-etherified C4; M-low-purity MTBE product; N-washing water; O-C4 after methanol removal; P-methanol aqueous solution; Q-methanol; R-water; T-C4 after washing; T-bottom extraction of light tower; U-1-butene product; V-n-butane / 2-butene-rich product. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments improved or adjusted by ordinary technicians in the field belong to the protection scope of the present invention.

[0030] A specific embodiment, an energy-saving process for producing methyl tert-butyl ether and 1-butene, is implemented based on the energy-saving device, and its process flow is as follows:

[0031] First, raw material A is heat exchanged with the bottom product of the pre-delightening tower in feed preheater A1, and then enters pre-delightening tower A2 for rectification operation to obtain top product B and bottom liquid product C, wherein product B is divided into two streams, one is product D, which enters pre-delightening tower / delightening tower heat exchanger A23 for condensation, and the other is product E, which enters pre-delightening tower / deweighting tower heat exchanger A26 for condensation. After the two streams after condensation are combined into product F, one part of the stream is used as reflux to enter the top of pre-delightening tower A2, and the other part of the stream is extracted as product S; product C is cooled by feed preheater A1 and enters raw material purification tank A4, mixed with raw material G in raw material purification tank A4, cooled by reaction feed cooler A5, and enters etherification reactor A6, in which most of isobutylene is etherified to generate MTBE, a part of which re-enters reaction feed cooler A5 as reflux, and a part of which is product I;

[0032] Secondly, product I enters the MTBE removal tower feed vaporizer A7, and enters the MTBE removal tower A8 after being partially vaporized, and high-purity MTBE is obtained at the bottom of the tower. A part of it is vaporized through a reboiler and enters the bottom of the MTBE removal tower A8, and the other part is extracted as product K, cooled by the catalytic distillation tower feed heat exchanger A11 and then sent out. The top product J is preheated by the catalytic distillation tower feed heat exchanger A11 and partially vaporized by the catalytic distillation tower feed vaporizer A12, and then enters the catalytic distillation tower A13 with the methanol raw material; product M is obtained at the bottom of the catalytic distillation tower A13, product L is cooled by the extraction tower feed cooler A16 and then enters the bottom of the extraction tower A17, and a water washing operation is performed in the extraction tower A17 to wash away most of the methanol, and product O is obtained at the top outlet of the tower, and product P is obtained at the bottom outlet of the tower; product P enters the methanol recovery tower A18, and product Q is obtained at the top of the tower, and product R is obtained at the bottom of the tower.

[0033] Finally, product O enters the light-removal tower A21, and through high-precision separation and distillation, product S is extracted from the liquid phase at the top of the tower, and product T is extracted from the bottom of the tower. Product T enters the post-heavy-removal tower A24. The heavy-removal tower A24 obtains product U at the top of the tower and product V at the bottom of the tower through high-precision separation and distillation.

[0034] Taking the pre-ether mixed C4 solution obtained from a refinery gas separation unit as an example, the composition of the pre-ether C4 solution A is shown in Table 1:

[0035] Table 1 Composition of pre-ether C4 solution A

[0036] name Pre-ether C4 solution A Temperature, °C 30 Pressure, MPa 1.65 Mass flow, kg / h 22000 Composition, mass fraction % C3 0.25 Isobutane 27.54 n-Butane 8.46 1-Butene 16.80 Isobutylene 24.31 2-Butene 22.64 C5 0.01

[0037] The energy-saving device and method for producing methyl tert-butyl ether and 1-butene of the present invention are used to purify the above-mentioned pre-ether C4 solution, i.e., raw material A. The specific process is as follows:

[0038] First, after the raw material A is heat exchanged with the bottom product of the pre-delightening tower in the feed preheater A1, the temperature is increased from 30°C to 50°C, and then it is fed from the pre-delightening tower A2. The theoretical number of plates of the pre-delightening tower A2 is 170, the mass reflux ratio is 28.25, the top pressure is 1.05Mpa, and the temperature of the isobutane gas phase produced B at the top of the pre-delightening tower A2 is 68°C. After condensation by the pre-delightening tower / delightening tower heat exchanger A23 and the pre-delightening tower / deheavy tower heat exchanger A26, the top reflux flow rate of the pre-delightening tower A2 is 146250kg / h, the isobutane product produced from the pre-delightening tower A2 is 5000kg / h, and the isobutane raw material C is produced from the liquid phase at the bottom of the pre-delightening tower A2 with a flow rate of 17000kg / h and a temperature of 78°C, which is 55°C after heat exchange in the feed preheater A1. The reboiler A3 of the light removal tower uses 130℃ heat medium water as the heat source, with an energy consumption of 11677kW.

[0039] The isobutane-removing raw material C at the bottom of the pre-light-removing tower A2 and the raw material methanol G enter the raw material purification tank A4 through a pressure difference and are evenly mixed, and then enter the etherification reactor A6. The reaction temperature is 40-60°C, and the outlet temperature of the etherification reactor A6 is 60°C. It is divided into two streams, one of which refluxes the reactants with a mass flow rate of 60750kg / h to the front of the reaction feed cooler A5, and the other stream of reactants with a mass flow rate of 20250kg / h is used as the preliminary etherification carbon four product I.

[0040] The preliminary etherification carbon four product I enters the de-MTBE tower feed vaporizer A7 through the pressure difference. After partial vaporization, the temperature rises from 57°C to 75°C, and then enters the 18th plate of the de-MTBE tower A8. The de-MTBE tower A8 has 40 theoretical plates, of which plates 2-18 are distillation plates, 19-41 are stripping plates, the top pressure is 0.7MPa, the mass reflux ratio is 0.9, and the de-MTBE product J is obtained at the top of the de-MTBE tower A8, with a flow rate of 12020kg / h and a temperature of 56°C. The high-purity MTBE product K is produced from the bottom of the de-MTBE tower A8 with a flow rate of 8230kg / h and a temperature of 70°C. The vaporizer uses 90°C heat medium water as the heat source, with a load of 1546kW. The de-MTBE tower reboiler A10 uses low-pressure steam as the heat source, with an energy consumption of 1016kW.

[0041] After the MTBE-removed product J is partially vaporized by the catalytic distillation tower feed vaporizer A12, the temperature rises from 49°C to 60°C, and then enters the 20th plate of the catalytic distillation tower A13, and the supplementary methanol G enters the 15th plate of the catalytic distillation tower A13. The catalytic distillation tower A13 has 42 theoretical plates, of which plates 2-9 are distillation plates, 10-19 are catalytic distillation plates, 20-41 are stripping plates, the top pressure is 0.6MPa, the mass reflux ratio is 0.4, and the isobutylene-removed carbon four solution L is obtained at the top of the catalytic distillation tower A13, with a flow rate of 12080kg / h and a temperature of 53°C. The low-purity MTBE product M is produced from the liquid phase at the bottom of the catalytic distillation tower A13 with a flow rate of 140kg / h and a temperature of 119°C. The vaporizer uses 90°C heat medium water as a heat source, and the load is 814kW. The reboiler A15 of the catalytic distillation tower uses low-pressure steam as the heat source, with an energy consumption of 527kW.

[0042] The flow rate of 12080kg / h of deisobutylene C4 solution L and the flow rate of 3450kg / h of extraction water N enter the extraction tower A17. The etherified C4 solution O is extracted from the top liquid phase of the extraction tower A17, and the methanol aqueous solution P is extracted from the bottom of the extraction tower A17 and fed to the 24th plate of the methanol recovery tower A18. The theoretical number of plates of the methanol recovery tower A18 is 40, the pressure is 1MPa, the mass reflux ratio is 2.4, the methanol product Q is extracted at a flow rate of 195kg / h and a temperature of 60°C. The bottom of the methanol recovery tower A18 is high-purity water R with a flow rate of 3102kg / h, a temperature of 100°C, and an energy consumption of 472KW.

[0043] After the removal of methanol ether, C4O enters the 62nd plate of the de-lightness tower A21 for feeding. The theoretical number of plates of the de-lightness tower A21 is 170, the mass reflux ratio is 47, and the top pressure is 0.55Mpa. The isobutane product produced from the top of the de-lightness tower A21 is 1350kg / h, which is combined with the isobutane product of the pre-de-lightness tower A2 at 5000kg / h and produced as the isobutane product F with a flow rate of 6350kg / h and a temperature of 61°C. The residual solution T is produced from the bottom of the de-lightness tower A21 with a flow rate of 10320kg / h and a temperature of 58°C. The isobutane 1# gas D from the top of the pre-de-lightness tower A2 is used as the heat source.

[0044] Solution T is fed from the 101st plate of de-weighting tower A24, which has 170 theoretical plates, a mass reflux ratio of 16, and a top pressure of 0.5 MPa. 1-Butene product U is produced from the top of de-weighting tower A24 with a flow rate of 3325 kg / h and a temperature of 43°C. n-Butane / 2-Butene-rich product V is produced from the bottom of de-weighting tower A24 with a flow rate of 6995 kg / h and a temperature of 55°C. Isobutane 2# gas D from the top of pre-de-light tower A2 is used as the heat source.

[0045] Table 2 Composition of isobutane product F

[0046] name Isobutane Product Summary F Temperature, °C 61 Pressure, MPa 1 Mass flow, kg / h 6350 Composition, mass fraction % C3 0.85 Isobutane 95.07 n-Butane 0 1-Butene 3.50 Isobutylene 0.56 2-Butene 0 C5 0

[0047] Table 3 Composition of high purity MTBE product L

[0048]

[0049]

[0050] Table 4 Composition of low-purity MTBE product M

[0051] name Low purity MTBE product M Temperature, °C 119 Pressure, MPa 0.65 Mass flow, kg / h 140 Composition, mass fraction % MTBE 91.69 2-Butene 3.95 C5 0.89 TBA 0.31 MSBE 3.04 n-Butane 0.09

[0052] Table 5 Refined 1-butene solution W composition

[0053]

[0054]

[0055] Table 6 Composition of 2-butene-rich solution X

[0056] name 2-Butene-rich solution V Temperature, °C 55 Pressure, MPa 0.55 Mass flow, kg / h 6995 Composition, mass fraction % n-Butane 26.56 1-Butene 2.31 2-Butene 71.04 water 0.06

[0057] The new process adds a pre-light removal tower and a MTBE removal tower, and changes some operating conditions in the original process, reducing the operating pressure of the catalytic distillation tower from 0.65MpaG to 0.55MpaG, the operating pressure of the light removal tower from 0.61MpaG to 0.45MpaG, and the operating pressure of the heavy removal tower from 1.1MpaG to 0.4MpaG. No changes were made to other equipment.

[0058] Table 7 Results comparison

[0059]

[0060]

[0061] Compared with the traditional process, the present invention adopts the method of pre-delightening and heat integration, using the top gas of the pre-delightening tower 2 as the heat source to provide heat for the bottom of the delightening tower 21 and the post-deweighting tower 24, which can reduce the processing capacity of the device by 19.8%, the energy consumption by 24.51%, and the total steam consumption of the device by 84.15%.

[0062] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An energy-saving device for producing methyl tert-butyl ether and 1-butene, characterized in that: The energy-saving device for producing methyl tert-butyl ether and 1-butene comprises a feed preheater (A1), a pre-light removal tower (A2), a pre-light removal tower reboiler (A3), a raw material purification tank (A4), a reaction feed cooler (A5), an etherification reactor (A6), a de-MTBE tower feed vaporizer (A7), a de-MTBE tower (A8), a de-MTBE tower condenser (A9), a de-MTBE tower reboiler (A10), a catalytic distillation tower feed heat exchanger (A11), a catalytic distillation tower feed vaporizer (A12), a catalytic Distillation tower (A13), catalytic distillation tower condenser (A14), catalytic distillation tower reboiler (A15), extraction tower feed cooler (A16), extraction tower (A17), methanol recovery tower (A18), methanol recovery tower condenser (A19), methanol recovery tower reboiler (A20), lightness removal tower (A21), lightness removal tower condenser (A22), pre-lightness removal tower / lightness removal tower heat exchanger (A23), de-weight removal tower (A24), de-weight removal tower condenser (A25), pre-lightness removal tower / weight removal tower heat exchanger (A26); The first inlet of the feed preheater (A1) inputs raw materials; The first outlet of the feed preheater (A1) is connected to the feed inlet at the bottom of the pre-light removal tower (A2); the second outlet of the feed preheater (A1) is connected to the first inlet of the raw material purification tank (A4); The bottom outlet of the pre-light-removal tower (A2) is connected to the pre-light-removal tower reboiler (A3) and the second inlet of the feed preheater (A1) respectively; the pre-light-removal tower reboiler (A3) is back-connected to the bottom inlet of the pre-light-removal tower (A2); the top outlet of the pre-light-removal tower (A2) is connected to the first inlet of the pre-light-removal tower / light-removal tower heat exchanger (A23) and the first inlet of the pre-light-removal tower / heavy-removal tower heat exchanger (A26) respectively through a three-way valve; The methanol feed is connected to the second inlet of the raw material purification tank (A4); the outlet of the raw material purification tank (A4) is connected to the inlet of the etherification reactor (A6) through the reaction feed cooler (A5); the outlet of the etherification reactor (A6) is respectively connected to the inlet of the reaction feed cooler (A5), the inlet of the MTBE removal tower vaporizer (A7), the inlet of the distillation tower feed vaporizer (A12), and the inlet of the extraction tower feed cooler (A16) through a three-way valve; the outlet of the MTBE removal tower vaporizer (A7) is connected to the inlet of the MTBE removal tower (A8); the top outlet of the MTBE removal tower (A8) is connected to the inlet of the MTBE removal tower condenser (A9); the outlet of the MTBE removal tower condenser (A9) is connected to the inlet of the MTBE removal tower condenser (A9); The first outlet of the catalytic distillation tower feed heat exchanger (A11) is connected to the inlet of the catalytic distillation tower feed vaporizer (A12) and the inlet of the extraction tower feed cooler (A16) through a three-way valve; the bottom outlet of the MTBE removal tower (A8) is connected to the reboiler (A10) of the MTBE removal tower and the second inlet of the catalytic distillation tower feed heat exchanger (A11); the reboiler (A10) of the MTBE removal tower is back-connected to the bottom inlet of the MTBE removal tower (A8); the second outlet of the catalytic distillation tower feed heat exchanger (A11) is connected to the high-purity MTBE product outlet; The outlet of the catalytic distillation tower feed vaporizer (A12) is connected to the first inlet of the catalytic distillation tower (A13); the methanol feed is connected to the second inlet of the catalytic distillation tower (A13); the top outlet of the catalytic distillation tower (A13) is connected to the inlet of the extraction tower feed cooler (A16) through the catalytic distillation tower condenser (A14); the catalytic distillation tower condenser (A14) is back-connected to the top inlet of the catalytic distillation tower (A13); the bottom outlet of the catalytic distillation tower (A13) is respectively connected to the catalytic distillation tower reboiler (A15) and the low-purity MTBE product outlet; the catalytic distillation tower reboiler (A15) is back-connected to the bottom inlet of the catalytic distillation tower (A13); The outlet of the extraction tower feed cooler (A16) is connected to the lower inlet of the extraction tower (A17); the water feed is connected to the upper inlet of the extraction tower (A17); the top outlet of the extraction tower (A17) is connected to the inlet of the light removal tower (A21); the bottom outlet of the extraction tower (A17) is connected to the inlet of the methanol recovery tower (A18); the top outlet of the methanol recovery tower (A18) is connected to the methanol product outlet through the methanol recovery tower condenser (A19); the methanol recovery tower condenser (A19) is back-connected to the inlet of the methanol recovery tower (A18); the bottom outlet of the methanol recovery tower (A18) is respectively connected to the methanol recovery tower reboiler (A20) and the water outlet; the methanol recovery tower reboiler (A20) is back-connected to the methanol recovery tower (A18). The bottom inlet of the collecting tower (A18); the top outlet of the lightness removal tower (A21) is connected to the isobutane product outlet through the lightness removal tower condenser (A22); the lightness removal tower condenser (A22) is back-connected to the top inlet of the lightness removal tower (A21); the bottom outlet of the lightness removal tower (A21) is back-connected to the bottom inlet of the lightness removal tower (A21) through the inlet of the pre-lightness removal tower / lightness removal tower heat exchanger (A23); the first outlet of the pre-lightness removal tower / lightness removal tower heat exchanger (A23) and the first outlet of the pre-lightness removal tower / weight removal tower heat exchanger (A26) are connected to the top inlet of the pre-lightness removal tower (A2) and the isobutane product outlet respectively after being combined; the second outlet of the pre-lightness removal tower / lightness removal tower heat exchanger (A23) is connected to the inlet of the weight removal tower (A24); The top outlet of the deweighting tower (A24) is connected to the 1-butene product outlet through the deweighting tower condenser (A25), and the deweighting tower condenser (A25) is back-connected to the top inlet of the deweighting tower (A24); the bottom outlet of the deweighting tower (A24) is respectively connected to the second inlet of the pre-light-removing tower / weight-removing tower heat exchanger b (A26) and the n-butane-rich / 2-butene product outlet; the outlet of the pre-light-removing tower / weight-removing tower heat exchanger b (A26) is connected to the bottom inlet of the deweighting tower (A24).

2. An energy-saving method for producing methyl tert-butyl ether and 1-butene, characterized in that: The device according to claim 1 is implemented as follows: First, the raw material (A) is heat exchanged with the bottom product of the pre-light-removing tower (A2) by the feed preheater (A1), and then enters the pre-light-removing tower (A2) for distillation operation to obtain the isobutane gas phase produced at the top of the tower (B) and the isobutane-removing raw material (C) at the bottom of the tower; wherein the isobutane gas phase produced (B) is divided into two streams, one is isobutane 1# gas (D), which enters the pre-light-removing tower / light-removing tower heat exchanger (A23) for condensation, and the other is isobutane 2# gas (E), which enters the pre-light-removing tower / heavy-removing tower heat exchanger (A26) for condensation; after the two condensed streams are combined, a part of the stream is used as reflux into The isobutane product (F) is extracted from the top of the pre-light-removing tower (A2), and another part of the stream is collected with the liquid phase extracted from the top of the light-removing tower (A21); the isobutane-removing raw material (C) is cooled in the feed preheater (A1) and then enters the raw material purification tank (A4), mixed with the raw material methanol (G) in the raw material purification tank (A4), cooled by the reaction feed cooler (A5), and then enters the etherification reactor (A6); an etherification reaction occurs in the etherification reactor (A6), one stream re-enters the reaction feed cooler (A5) as reflux, and the other stream is the preliminary etherification C4 product (I); The preliminary etherified C4 product (I) is selectively fed into the de-MTBE tower feed vaporizer (A7) and / or the extraction tower feed cooler (A16) according to the process requirements, and then partially vaporized into the de-MTBE tower feed vaporizer (A7) and then fed into the de-MTBE tower (A8). The stream obtained at the bottom of the tower is divided into two streams, one of which is vaporized by the de-MTBE tower reboiler (A10) and then fed into the de-MTBE tower (A8) bottom, and the other is cooled by the catalytic distillation tower feed heat exchanger (A11) and then extracted as a high-purity MTBE product (K); the de-MTBE product (J) is obtained from the top of the de-MTBE tower (A8) through the de-MTBE tower condenser (A9), and then preheated by the catalytic distillation tower feed heat exchanger (A11), and then selectively fed into the catalytic distillation tower feed vaporizer (A12) and / or the extraction tower feed cooler according to the process requirements. (A16); the MTBE-free product (J) is partially vaporized in the catalytic distillation tower feed vaporizer (A12), and then enters the catalytic distillation tower (A13) with the methanol raw material (G); a low-purity MTBE product (M) is obtained at the bottom of the catalytic distillation tower (A13); the etherified C4 (L) at the top of the catalytic distillation tower (A13) is passed through the catalytic distillation tower condenser (A14) to the extraction tower feed cooler (A16), and after cooling, enters the bottom inlet of the extraction tower (A17); the washing water (N) enters the top inlet of the extraction tower (A17), and the methanol-free etherified C4 (O) is obtained at the top outlet of the extraction tower (A17), and the methanol aqueous solution (P) is obtained at the bottom outlet of the extraction tower (A17); the methanol aqueous solution (P) enters the methanol recovery tower (A18), and methanol (Q) is obtained at the top of the tower, and water (R) is obtained at the bottom of the tower; After the removal of methanol ether, C4 (O) enters the light-removing tower (A21), and the isobutane product (F) is produced in the liquid phase at the top of the tower, and the bottom of the light-removing tower (T) is produced at the bottom of the tower. The bottom of the light-removing tower (T) enters the heavy-removing tower (A24); the 1-butene product (U) is obtained at the top of the heavy-removing tower (A24), and the n-butane / 2-butene-rich product (V) is obtained at the bottom of the tower.

3. An energy-saving method for producing methyl tert-butyl ether and 1-butene according to claim 2, wherein the sum of the concentrations of propane, propylene, isobutane, normal butane, cis-2-butene and trans-2-butene in the raw material (A) is less than 60wt%, the concentration of isobutylene is less than 50wt%, the concentration of 1-butene is less than 50wt%, and the sum of the concentrations of the remaining components is less than 20wt%.

4. According to the energy-saving method for producing methyl tert-butyl ether and 1-butene according to claim 3, the process parameters are as follows: The number of theoretical plates of the pre-light-removal tower (A2) is 60 to 180, the reflux ratio is 10 to 60, and the tower operating pressure is 0.7 to 1.4 MPa; the number of theoretical plates of the MTBE removal tower (A8) is 10 to 180, and the tower operating pressure is 0.3 to 1.4 MPa; the number of theoretical plates of the catalytic distillation tower (A13) is 10 to 180, the reflux ratio is 0.5 to 10, and the tower operating pressure is 0.5 to 1.4 MPa; the number of theoretical plates of the light-removal tower (A22) is 10 to 180, the reflux ratio is 5 to 60, and the tower operating pressure is 0.5 to 0.8 MPa; the number of theoretical plates of the de-weighting tower (A25) is 10 to 180, the reflux ratio is 5 to 60, and the tower operating pressure is 0.4 to 0.8 MPa; The pre-light removal tower (A2) uses 70-180°C hot water as a heat source; the MTBE removal tower feed vaporizer (A7) and the catalytic distillation tower feed vaporizer (A12) use 70-180°C hot water as a heat source; The reboiler of the MTBE removal tower (A10) and the reboiler of the catalytic distillation tower (A15) use 0.1-5 MPa steam as a heat source.

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