Energy-saving system for preparing dimethyl ether from methanol

Abstract

The utility model discloses an energy-saving system for preparing dimethyl ether from methanol, and belongs to the technical field of dimethyl ether preparation. The system comprises a methanol gasification tower, an in-tower gas-gas heat exchanger, a crude DME preheating system, a DME rectification system and the like, and reaction heat produced by reaction passes through the in-tower gas-gas heat exchanger and the methanol gasification tower and is exchanged to raw materials. The system overcomes the problem of high energy consumption of the existing process for producing dimethyl ether by a two-step method, provides a process for preparing dimethyl ether by methanol dehydration, which has the advantages of heat stepped utilization, waste heat stepped recovery, lower energy consumption and higher heat energy utilization rate, and has the effects of energy conservation and consumption reduction.

Description

Technical Field

[0001] The utility model relates to an energy-saving system for preparing dimethyl ether from methanol, and belongs to the technical field of dimethyl ether preparation. Background Art

[0002] Dimethyl ether is an important chemical raw material that can be used as fuel, refrigerant, aerosol, chemical intermediate, etc. As a clean energy and important chemical raw material, the market demand for dimethyl ether is showing a rapid growth trend.

[0003] Industrially, dimethyl ether (DME) production mainly involves a two-step process (methanol dehydration to DME) and a one-step process (direct synthesis of DME from synthesis gas). The one-step synthesis gas process is currently in the exploratory stage of industrialization, with no reports of industrialization yet. The two-step process is further divided into liquid-phase and vapor-phase processes. The liquid-phase process presents challenges such as equipment corrosion, severe environmental pollution, and difficulty in product post-processing. Currently, the most widely used process is vapor-phase methanol dehydration to produce DME. While this vapor-phase methanol dehydration process offers low investment, flexible product adjustments, and a simple process, it also suffers from insufficient utilization of waste heat and high energy consumption. The main reactions in this process are as follows.

[0004] 2CH3OH=CH3OCH3 +H2O-23.14kJ / mol

[0005] The reaction is exothermic, with a heat of -23.14 kJ / mol per mol of dimethyl ether produced. Therefore, the heat of the synthesis reaction of dimethyl ether from methanol dehydration has great value for recycling. Utility Model Content

[0006] In order to solve the problems existing in the prior art, the utility model provides an energy-saving system for producing dimethyl ether from methanol, which fully utilizes the reaction heat generated in the process of producing dimethyl ether.

[0007] To achieve the above-mentioned object, the technical solution of the present invention is as follows: an energy-saving methanol-to-dimethyl ether system, in which the shell outlet of the methanol gasification tower is connected to the start-up heater by a pipeline, the start-up heater is connected to the shell inlet of the tower inlet gas-to-gas heat exchanger by a pipeline, and the shell outlet of the tower inlet gas-to-gas heat exchanger is connected to the inlet of the crude DME reactor by a pipeline;

[0008] The outlet of the crude DME reactor is connected by a pipeline to the pipe layer inlet of the gas-to-gas heat exchanger entering the tower, the pipe layer outlet of the gas-to-gas heat exchanger entering the tower is connected to the pipe layer inlet of the methanol vaporization tower, the pipe layer outlet of the methanol vaporization tower is connected to the inlet of the crude DME storage tank after passing through the DME cooler; the outlet of the crude DME storage tank is connected to the shell layer inlet of the crude DME preheater after passing through the crude DME transfer pump, the shell layer outlet of the crude DME preheater is connected to the product inlet of the DME distillation system; the product outlet of the DME distillation system is connected to the finished product tank;

[0009] The steam pipe of the pipe network is connected to the steam inlet of the DME distillation system, the steam outlet of the DME distillation system is connected to the pipe layer inlet of the crude DME preheater, and the pipe layer outlet of the crude DME preheater is connected to the steam condensation system;

[0010] The methanol outlet of the DME distillation system is connected to the shell inlet of the methanol vaporization tower via a methanol recovery delivery pump and a methanol recovery pipeline.

[0011] Furthermore, the crude DME reactor is an adiabatic reactor.

[0012] Furthermore, the sewage outlet of the DME distillation system is connected to a sewage treatment system.

[0013] Compared with existing technologies, this utility model has the following advantages: the system includes a methanol vaporization tower, an inlet gas-to-gas heat exchanger, a crude DME preheating system, and a DME distillation system. The reaction heat generated is transferred to the raw material through the inlet gas-to-gas heat exchanger and the methanol vaporization tower. This system overcomes the high energy consumption drawback of existing two-step dimethyl ether production processes. Building on the mature and widely used two-step dimethyl ether production technology in China, this system provides a methanol dehydration process for producing dimethyl ether with tiered heat utilization and waste heat recovery, resulting in lower energy consumption and higher thermal energy utilization, significantly reducing energy consumption and consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of an energy-saving methanol-to-dimethyl ether system.

[0015] In the figure: F-101, methanol gasification tower, H-101, start-up heater, E-101, inlet gas-to-gas heat exchanger, E-102, DME cooler, E-103, crude DME preheater, R-101, crude DME reactor, P-101A / B, crude DME transfer pump, P-102A / B, recovered methanol transfer pump, V-101, crude DME storage tank, T-101, DME distillation system. DETAILED DESCRIPTION

[0016] The following will be combined with specific embodiments and examples to specifically explain the present invention, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are used to illustrate the present invention, rather than to limit the present invention.

[0017] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this utility model belongs. In the event of any conflict, the present specification shall take precedence.

[0018] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0019] Figure 1 The present invention shows an energy-saving methanol-to-dimethyl ether system, in which the shell outlet of the methanol gasification tower F-101 is connected to the start-up heater H-101 by a pipeline, the start-up heater H-101 is connected to the shell inlet of the tower gas-to-gas heat exchanger E-101 by a pipeline, the shell outlet of the tower gas-to-gas heat exchanger E-101 is connected to the inlet of the crude DME reactor R-101 by a pipeline; the outlet of the crude DME reactor R-101 is connected to the pipe layer inlet of the tower gas-to-gas heat exchanger E-101 by a pipeline, and the pipe layer inlet of the tower gas-to-gas heat exchanger E-101 is connected to the inlet of the crude DME reactor R-101. The layer outlet is connected to the pipe layer inlet of the methanol vaporization tower F-101, and the pipe layer outlet of the methanol vaporization tower F-101 is connected to the inlet of the crude DME storage tank V-10 after passing through the DME cooler E-102; the outlet of the crude DME storage tank V-10 is connected to the shell layer inlet of the crude DME preheater E-103 after passing through the crude DME transfer pump P-101A / B, and the shell layer outlet of the crude DME preheater E-103 is connected to the product inlet of the DME distillation system T-101; the product outlet of the DME distillation system T-101 is connected to the finished product tank.

[0020] The steam pipe network connects to the steam inlet of the DME distillation system T-101. The steam outlet of the DME distillation system T-101 is connected to the pipe layer inlet of the crude DME preheater E-103. The pipe layer outlet of the crude DME preheater E-103 is connected to the steam condensation system. The methanol outlet of the DME distillation system T-101 is connected to the shell layer inlet of the methanol vaporization tower F-101 via the recovered methanol delivery pumps P-102A / B and the methanol recovery pipeline. The crude DME reactor R-101 is an adiabatic reactor. The wastewater outlet of the DME distillation system T-101 is connected to the wastewater treatment system.

[0021] The process flow of the above technical solution includes: ① mixing the methanol from the tank area with the recovered methanol delivered by the recovered methanol delivery pump P-102A / B from the distillation system, and then passing through the methanol vaporization tower F-101 (shell layer), the start-up heater H-101, and the tower inlet gas-to-gas heat exchanger E-101 (shell layer) for two-stage heat exchange before entering the crude DME reactor R-101; ② the reaction gas from the crude DME reactor R-101 is heated by the tower inlet gas-to-gas heat exchanger E-101 (tube layer). After fully utilizing the heat in methanol vaporizer F-101 (tube layer), the crude DME passes through crude DME cooler E-102 and enters crude DME storage tank V-101. ③ Crude DME from crude DME storage tank V-101 flows through crude DME transfer pumps P-101A / B, crude DME preheater E-103 (shell layer), and enters DME distillation system T-101. ④ Steam from the pipeline network passes through the distillation column kettle reboiler and enters crude DME preheater E-103 (tube layer) for further heat utilization. After passing through DME distillation system T-101, the finished dimethyl ether is sent to the tank farm.

[0022] Compared with the prior art, the utility model can reasonably and fully utilize the heat generated in the entire production system and the heat of the distillation steam, the route is more optimized, and the equipment investment can also be reduced, which is suitable for large-scale industrialization.

[0023] The above description is merely an embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, it is not intended to limit the present application. Any technical personnel familiar with this profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An energy-saving methanol-to-dimethyl ether system, characterized by: In this system, the shell outlet of the methanol vaporizer (F-101) is connected to the start-up heater (H-101) by a pipeline, the start-up heater (H-101) is connected to the shell inlet of the inlet gas-to-gas heat exchanger (E-101) by a pipeline, and the shell outlet of the inlet gas-to-gas heat exchanger (E-101) is connected to the inlet of the crude DME reactor (R-101) by a pipeline; The outlet of the crude DME reactor (R-101) is connected to the tube layer inlet of the tower inlet gas-to-gas heat exchanger (E-101) by a pipeline, the tube layer outlet of the tower inlet gas-to-gas heat exchanger (E-101) is connected to the tube layer inlet of the methanol vaporization tower (F-101), the tube layer outlet of the methanol vaporization tower (F-101) is connected to the inlet of the crude DME storage tank (V-10) after passing through the DME cooler (E-102); the outlet of the crude DME storage tank (V-10) is connected to the shell layer inlet of the crude DME preheater (E-103) after passing through the crude DME transfer pump (P-101A / B), the shell layer outlet of the crude DME preheater (E-103) is connected to the product inlet of the DME distillation system (T-101); the product outlet of the DME distillation system (T-101) is connected to the finished product tank; The steam pipe of the pipe network is connected to the steam inlet of the DME distillation system (T-101), the steam outlet of the DME distillation system (T-101) is connected to the pipe layer inlet of the crude DME preheater (E-103), and the pipe layer outlet of the crude DME preheater (E-103) is connected to the steam condensation system; The methanol outlet of the DME distillation system (T-101) is connected to the shell inlet of the methanol vaporization tower (F-101) through the methanol recovery pump (P-102A / B) and the methanol recovery pipeline.

2. The energy-saving methanol-to-dimethyl ether system according to claim 1, characterized in that: The crude DME reactor (R-101) is an adiabatic reactor.

3. The energy-saving methanol-to-dimethyl ether system according to claim 1, characterized in that: The wastewater outlet of the DME distillation system (T-101) is connected to the wastewater treatment system.

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