Methanol synthesis system capable of reducing wax precipitation

Abstract

The utility model discloses a methanol synthesis system capable of reducing paraffin precipitation, which comprises a fresh gas-oil separator, an exhaust port of the fresh gas-oil separator is connected with a gas inlet of a fine desulfurization tower, an exhaust port of the fine desulfurization tower is connected with an inlet of a tower-front preheating gas inlet pipe, an outlet of the tower-front preheating gas inlet pipe is connected with a cold source inlet of a tower-front preheater, and a cold source outlet of the tower-front preheater is connected with a cold source outlet of the fine desulfurization tower. A cold source outlet of the pre-tower preheater is connected with an inlet of the methanol synthesis tower, an outlet of the methanol synthesis tower is connected with a heat source inlet of the pre-tower preheater, and a heat source outlet of the pre-tower preheater is connected with an inlet of the methanol separation section. The heat of the deoxidation reactor and the methanol synthesis tower is utilized, and fresh gas fed into the deoxidation reactor and synthesis gas fed into the methanol synthesis tower are preheated through the front preheater and the deoxidation preheater respectively, so that the temperature of the whole methanol synthesis system is increased, and the wax precipitation condition in winter is reduced; the problems of reduction of heat transfer efficiency, increase of fluid resistance and the like caused by wax precipitation are effectively avoided, and continuous operation of a production system can be guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of methanol synthesis, in particular to a methanol synthesis system capable of reducing wax deposition. Background Art

[0002] At present, the industry almost always uses the pressurized catalytic hydrogenation of carbon monoxide and carbon dioxide to synthesize methanol. In Inner Mongolia, carbon monoxide and carbon dioxide mainly come from the synthesis gas produced by coal gasification, so the synthesis gas will contain long-chain hydrocarbons.

[0003] In the process of methanol production, especially at low temperatures, long-chain hydrocarbons tend to form wax deposits (i.e. waxing) on ​​the surfaces of pipes, heat exchangers and other equipment. Waxing not only reduces the heat transfer efficiency of the equipment and increases fluid resistance, but in severe cases may also cause equipment blockage, production interruption and even safety accidents. This phenomenon is particularly serious in low-temperature areas and winter operations, posing a huge challenge to the safe and stable operation of methanol units.

[0004] Therefore, the technology of reducing wax deposition in methanol units is of great significance for improving the operating efficiency of methanol units, reducing equipment maintenance costs, extending equipment service life, and ensuring the continuity and safety of the production process. Utility Model Content

[0005] The utility model aims to provide a methanol synthesis system capable of reducing wax deposition.

[0006] The utility model is implemented by the following technical solutions:

[0007] A methanol synthesis system capable of reducing wax deposition comprises a fresh gas-oil separator, wherein the exhaust port of the fresh gas-oil separator is connected to the air inlet of a fine desulfurization tower, the exhaust port of the fine desulfurization tower is connected to the inlet of a preheating air inlet pipe before the tower, the outlet of the preheating air inlet pipe before the tower is connected to the cold source inlet of a preheater before the tower, the cold source outlet of the preheater before the tower is connected to the inlet of a methanol synthesis tower, the outlet of the methanol synthesis tower is connected to the heat source inlet of the preheater before the tower, and the heat source outlet of the preheater before the tower is connected to the inlet of a methanol separation section;

[0008] The exhaust port of the fine desulfurization tower is also connected to the cold source inlet of the deoxidation preheater, the cold source outlet of the deoxidation preheater is connected to the air inlet of the deoxidation reactor, the exhaust port of the deoxidation reactor is connected to the heat source inlet of the deoxidation preheater, and the heat source outlet of the deoxidation preheater is connected to the inlet of the preheating air inlet pipe before the tower;

[0009] The exhaust port of the fine desulfurization tower is also connected to the air inlet of the deoxygenation reactor through a deoxygenation temperature regulating pipe, a deoxygenation temperature regulating valve is installed on the deoxygenation temperature regulating pipe, and a deoxygenation temperature sensor is installed at the air inlet of the fine desulfurization tower, and the signal output end of the deoxygenation temperature sensor is electrically connected to the signal input end of the deoxygenation temperature regulating valve.

[0010] Preferably, it further comprises a circulating gas-oil separator, the exhaust port of the circulating gas-oil separator being connected to the air inlet of the preheating air inlet pipe before the tower.

[0011] Preferably, the outlet of the preheating air inlet pipe before the tower is also connected to the inlet of the methanol synthesis tower through a synthesis tower temperature regulating pipe, and a one-way valve is installed on the synthesis tower temperature regulating pipe.

[0012] The utility model has the advantages of utilizing the heat of the deoxygenation reactor and the methanol synthesis tower to preheat the fresh gas sent to the deoxygenation reactor and the synthesis gas of the methanol synthesis tower through the front preheater and the deoxygenation preheater respectively, thereby increasing the temperature of the entire methanol synthesis system, reducing the occurrence of waxing in winter, and effectively avoiding the problems of reduced heat transfer efficiency and increased fluid resistance caused by waxing, thereby ensuring the continuous operation of the production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the utility model.

[0014] In the figure: fresh gas-oil separator 1, fine desulfurization tower 2, preheating air inlet pipe before tower 3, preheater before tower 4, methanol synthesis tower 5, deoxygenation preheater 6, deoxygenation reactor 7, deoxygenation temperature regulating pipe 8, deoxygenation temperature regulating valve 9, deoxygenation temperature sensor 10, circulating gas-oil separator 11, synthesis tower temperature regulating pipe 12, and one-way valve 13. DETAILED DESCRIPTION

[0015] like Figure 1 As shown, a methanol synthesis system capable of reducing wax deposition comprises a fresh gas-oil separator 1, an exhaust port of the fresh gas-oil separator 1 is connected to an air inlet of a fine desulfurization tower 2, an exhaust port of the fine desulfurization tower 2 and an exhaust port of a circulating gas-oil separator 11 are both connected to an air inlet of a pre-tower preheating air inlet pipe 3, an outlet of the pre-tower preheating air inlet pipe 3 is connected to a cold source inlet of a pre-tower preheater 4, a cold source outlet of the pre-tower preheater 4 is connected to an inlet of a methanol synthesis tower 5, an outlet of the methanol synthesis tower 5 is connected to a heat source inlet of the pre-tower preheater 4, and a heat source outlet of the pre-tower preheater 4 is connected to an inlet of a methanol separation section;

[0016] The exhaust port of the fine desulfurization tower 2 is also connected to the cold source inlet of the deoxidation preheater 6, the cold source outlet of the deoxidation preheater 6 is connected to the air inlet of the deoxidation reactor 7, the exhaust port of the deoxidation reactor 7 is connected to the heat source inlet of the deoxidation preheater 6, and the heat source outlet of the deoxidation preheater 6 is connected to the inlet of the preheating air inlet pipe 3 before the tower;

[0017] Fresh gas is fresh synthesis gas, which passes through the fresh gas oil separator 1 to remove oil and water, enters the top of the fine desulfurization tower 2 to remove residual organic sulfur and inorganic sulfur, and then comes out from the lower part of the desulfurization tower; circulating gas is the synthesis gas separated after methanol synthesis, which passes through the circulating gas oil separator 11 to remove oil and water. If the fresh gas composition meets the production requirements, the circulating gas and the fresh gas enter the pre-tower preheating inlet pipe 3 together, and enter the pre-tower preheater 4 after mixing. After heat exchange, they are preheated to 215°C and enter the catalyst layer from the top of the methanol synthesis tower 5. The gas entering the methanol synthesis tower 5 passes through the catalyst layer from top to bottom for synthesis reaction. The gas after the reaction is discharged from the bottom of the methanol synthesis tower 5, and then enters the pre-tower preheater 4 from the top as a heat source to preheat the gas sent from the pre-tower preheating inlet pipe 3, and finally sent to the methanol separation section for further treatment.

[0018] The exhaust port of the fine desulfurization tower 2 is also connected to the air inlet of the deoxygenation reactor 7 through a deoxygenation temperature regulating pipe 8, a deoxygenation temperature regulating valve 9 is installed on the deoxygenation temperature regulating pipe 8, and a deoxygenation temperature sensor 10 is installed at the air inlet of the fine desulfurization tower 2, and the signal output end of the deoxygenation temperature sensor 10 is electrically connected to the signal input end of the deoxygenation temperature regulating valve 9;

[0019] In actual production, since there is still oxygen in the fresh gas, it will affect the activity of the catalyst and increase the side reactions in the methanol synthesis process. Therefore, the fresh gas needs to be directly sent to the deoxygenation preheater 6. The deoxygenation preheater 6 heats the fresh gas to 140-180°C before entering the deoxygenation reactor 7. The temperature of the deoxygenated gas is about 260°C. After entering the deoxygenation preheater 6 as a heat source to heat the fresh gas, it comes out from the bottom and is then sent to the preheating inlet pipe 3 before the tower. The heat generated by the deoxygenation reaction will increase the temperature of the synthesis gas sent to the preheater 4 before the tower, and at the same time, the temperature of the fresh gas sent to the deoxygenation reactor 7 will be increased through the deoxygenation preheater 6.

[0020] The temperature of the fresh gas entering the deoxygenation reactor 7 is detected by the deoxygenation temperature sensor 10, and the opening of the deoxygenation temperature regulating valve 9 is controlled by the detected temperature, so that a part of the fresh gas that has not been heated by the deoxygenation preheater 6 is mixed with the heated fresh gas through the deoxygenation temperature regulating pipe 8 and then sent to the deoxygenation reactor 7, which can prevent the reaction temperature of the deoxygenation reactor 7 from being too high;

[0021] The outlet of the preheating air inlet pipe 3 is also connected to the inlet of the methanol synthesis tower 5 through the synthesis tower temperature regulating pipe 12, and a one-way valve 13 is installed on the synthesis tower temperature regulating pipe 12; in order to further control the inlet temperature of the methanol synthesis tower 5, the valve on the synthesis tower temperature regulating pipe 12 can be opened, so that a small amount of synthesis gas in the preheating air inlet pipe 3 before the tower is not heated by the preheater 4 before the tower, and is mixed with the synthesizer coming out of the preheater 4 at the inlet of the methanol synthesis tower 5, so as to achieve fine adjustment of lowering the temperature, and the one-way valve 13 is used to prevent the synthesis gas from flowing back.

[0022] The utility model utilizes the heat of the deoxygenation reactor 7 and the methanol synthesis tower 5, and preheats the fresh gas sent to the deoxygenation reactor 7 and the synthesis gas of the methanol synthesis tower 5 through the front preheater and the deoxygenation preheater 6 respectively, so as to increase the temperature of the entire methanol synthesis system, reduce the occurrence of waxing in winter, effectively avoid the problems of reduced heat transfer efficiency and increased fluid resistance caused by waxing, and ensure the continuous operation of the production system.

[0023] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A methanol synthesis system capable of reducing wax deposition, characterized in that: It comprises a fresh gas-oil separator, wherein the exhaust port of the fresh gas-oil separator is connected to the air inlet of the fine desulfurization tower, the exhaust port of the fine desulfurization tower is connected to the inlet of the preheating air inlet pipe before the tower, the outlet of the preheating air inlet pipe before the tower is connected to the cold source inlet of the preheater before the tower, the cold source outlet of the preheater before the tower is connected to the inlet of the methanol synthesis tower, the outlet of the methanol synthesis tower is connected to the heat source inlet of the preheater before the tower, and the heat source outlet of the preheater before the tower is connected to the inlet of the methanol separation section; The exhaust port of the fine desulfurization tower is also connected to the cold source inlet of the deoxidation preheater, the cold source outlet of the deoxidation preheater is connected to the air inlet of the deoxidation reactor, the exhaust port of the deoxidation reactor is connected to the heat source inlet of the deoxidation preheater, and the heat source outlet of the deoxidation preheater is connected to the inlet of the preheating air inlet pipe before the tower; The exhaust port of the fine desulfurization tower is also connected to the air inlet of the deoxygenation reactor through a deoxygenation temperature regulating pipe, a deoxygenation temperature regulating valve is installed on the deoxygenation temperature regulating pipe, and a deoxygenation temperature sensor is installed at the air inlet of the fine desulfurization tower, and the signal output end of the deoxygenation temperature sensor is electrically connected to the signal input end of the deoxygenation temperature regulating valve.

2. A methanol synthesis system capable of reducing wax deposition according to claim 1, characterized in that: It also includes a circulating gas-oil separator, the exhaust port of which is connected to the air inlet of the preheating air inlet pipe in front of the tower.

3. A methanol synthesis system capable of reducing wax deposition according to claim 1 or 2, characterized in that: The outlet of the preheating air inlet pipe before the tower is also connected to the inlet of the methanol synthesis tower through a synthesis tower temperature regulating pipe, and a one-way valve is installed on the synthesis tower temperature regulating pipe.

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