A device for preparing acetylene by partial oxidation of natural gas and energy-saving method

Abstract

The present invention belongs to the technical field of natural gas chemical industry, energy utilization and waste heat recovery, and discloses a device and energy-saving method for preparing acetylene by partial oxidation of natural gas. Preheated natural gas and oxygen are uniformly mixed, and reacted by ignition to obtain high-temperature cracking gas. The high-temperature product is quenched by using the normal-temperature cracking mixed gas as the quenching gas to terminate the consumption reaction of acetylene; the coking of the vessel wall is suppressed by using the normal-temperature synthesis gas as the protective gas. The high-temperature cracking mixed gas exchanges heat with the raw material through the raw gas heat exchange chamber, and the carbon black powder is separated and then heated to soft water to produce high-pressure steam. The high-temperature carbon black water obtained by water washing is then heated to soft water to produce high-temperature hot water. The normal-temperature cracking mixed gas is separated to obtain acetylene and synthesis gas. The present invention adopts four-stage cooling and three-stage energy recovery and utilization, which greatly improves the utilization rate of thermal energy, while reducing the cost of vessel wall coking and equipment investment, and produces high-quality carbon black powder as a by-product. It is environmentally friendly and has good economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas chemical industry, energy utilization and waste heat recovery, and in particular to a device for preparing acetylene by partial oxidation of natural gas and an energy-saving method. Background Art

[0002] Acetylene is a very important organic chemical raw material, widely used in metal processing and the preparation of chemical products such as ethylene and vinyl chloride. The partial oxidation of natural gas to produce acetylene is one of the main methods for preparing acetylene at present, and it is also a clean acetylene production technology suitable for my country's national conditions. In this process, the preheated natural gas and oxygen are fully mixed, and part of the natural gas is burned to provide heat for the remaining natural gas to crack. The cracked gas is terminated by rapid cooling to obtain low-temperature cracked gas, and the product acetylene and synthesis gas are obtained through subsequent separation and other processes. This process has the characteristics of high reaction temperature, easy polymerization of certain products, millisecond-level reaction and rapid termination. Rapid cooling is an important part of the process, which not only affects the yield and quality of acetylene products, but the heat loss during the process is also one of the important issues restricting the development of the process.

[0003] In traditional processes, water or oil is often used to form a water curtain or oil curtain in the quench chamber after the combustion chamber to quench the high-temperature cracking gas. In addition, there are many other patented technologies for quenching high-temperature cracking gas. Patent CN 1064947 C uses water as a quenching medium to recirculate it in a closed system, avoiding the consumption of the quenching medium during the process; Patent US 3242225 uses aromatic oil as a quenching agent, and the cracking gas eventually drops to 200-300°C. The high-temperature heat of the quenching agent is used to heat soft water to produce high-temperature water vapor, thereby improving the utilization rate of waste heat; Patent CN 102329189 A uses circulating room-temperature synthesis gas as a quenching medium, converts the cracking gas from high temperature to medium temperature without introducing new impurities to terminate the reaction, and recovers the remaining heat; Patent CN108218653A uses circulating room-temperature cracking gas as a quenching medium to cool the high-temperature cracking gas and recover heat, which reduces the energy consumption of the separation and compression processes to a certain extent.

[0004] Although the above devices and processes can terminate the reaction, the high-temperature cracking gas in the traditional process is directly reduced from more than 1300℃ to 80-100℃, and the heat is absorbed by the quenching water or oil, and no other efficient utilization is performed, resulting in a large amount of energy loss and economic losses. In addition, the carbon black water after quenching volatilizes a large amount of aromatics in the subsequent device to pollute the environment. When aromatic oil is used as the quenching medium, a part of it will be cracked and consumed under high temperature conditions during the quenching process, and the cracking gas components are complex, which requires regular replenishment of aromatic oil and increases the difficulty of separation; using synthesis gas as the quenching medium, although heat loss is avoided to a certain extent, the subsequent separation and compression processes will consume a lot of energy, resulting in low overall heat utilization; using room temperature cracking gas as the quenching medium, the content of acetylene and cracking intermediates increases greatly, making the vessel wall more prone to coking. Although the subsequent patents have recovered heat to a certain extent, they are single-purpose and still have a lot of losses, resulting in low heat utilization of part of the high-temperature cracking gas. Summary of the invention

[0005] To further solve the above problems, the present invention provides a device and energy-saving method for preparing acetylene by partial oxidation of natural gas in view of the prior art. It adopts four-stage cooling and three-stage energy recovery and utilization, which greatly improves the thermal energy utilization rate, reduces the cost of vessel wall decoking and equipment investment, and produces high-quality carbon black powder as a by-product, thereby having good economic benefits.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A device for preparing acetylene by partial oxidation of natural gas, the device comprising: a mixing chamber A, a reaction chamber B, a cracking gas quenching chamber C, a raw gas heat exchange chamber D, a dust collector E, a waste heat boiler F, a water scrubber G, a boiler water heater H, a carbon remover I, an acetylene separation device J, a compressor aK1, a compressor bK2, a heater aL1, a heater bL2, and a burner M.

[0008] Preferably, the mixing chamber A, the burner M, the reaction chamber B, the cracking gas quenching chamber C and the raw gas heat exchange chamber D are connected in sequence to form a natural gas partial oxidation acetylene reactor; the raw gas pipeline is connected to the inlet of the mixing chamber A through the heater respectively; the burner M is connected to the outlet of the mixing chamber A and the inlet of the reaction chamber B; the cracking gas quenching chamber C is located below the reaction chamber B; the raw gas heat exchange chamber D is fixed inside the natural gas partial oxidation acetylene reactor, and is located below the cracking gas quenching chamber C; the raw gas heat exchange chamber D is provided with a normal temperature natural gas 3 inlet, a normal temperature oxygen 4 inlet, a high temperature natural gas 5 outlet, and a high temperature oxygen 6 outlet, the two inlets are connected to the raw gas pipeline, and the two outlets are connected to the inlet of the mixing chamber A; the bottom of the raw gas heat exchange chamber D is connected to the mixed gas outlet device D6; the outlet of the mixed gas outlet device D6 is connected to the inlet of the dust collector E; the outlet pipeline of the dust collector E is divided into two, one outlet pipeline is connected to the mixed gas inlet of the waste heat boiler F, and the other outlet pipeline is the carbon black powder 13 product outlet; the mixed gas outlet of the waste heat boiler F is connected to the gas phase inlet at the bottom of the water scrubber G; water supply The 15 pipeline is connected to the water inlet of the waste heat boiler F, and the steam generated after heat exchange is discharged from the high-pressure steam outlet 14 of the waste heat boiler F; the water supply 15 pipeline is connected to the cooling water inlet at the top of the water scrubber G, and the mixed gas is in countercurrent contact with the cooling water; the gas phase outlet pipeline of the water scrubber G is divided into two, one gas phase outlet pipeline is connected to the room temperature cracked mixed gas a9 inlet of the cracked gas quenching chamber C via the compressor aK1, and the other gas phase outlet pipeline is connected to the acetylene separation device J inlet; the liquid phase outlet pipeline of the water scrubber G is connected to the boiler water heater H product inlet pipeline; the boiler water heater H product outlet is connected to the decarbonizer I inlet pipeline; the water supply 15 pipeline is connected to the water inlet of the boiler water heater H, and is discharged from the high-temperature hot water 16 outlet after heat exchange; the solid phase outlet of the decarbonizer I is connected to the carbon black powder 13 outlet pipeline, and the liquid phase outlet is connected to the water supply 15 pipeline; the acetylene separation device J outlet pipeline is divided into two, one outlet pipeline is connected to the normal temperature synthesis gas 11 inlet of the cracking gas quenching chamber C via the compressor bK2, and the other is the acetylene / synthesis gas product outlet 12.

[0009] Preferably, a plurality of heat exchange tubes D2 are provided in the raw gas heat exchange chamber D, and the inner surface of the heat exchange tube D2 is coated with a high-temperature resistant coking inhibition coating; the inlet of the heat exchange tube D2 is connected to the outlet of the cracking gas quenching chamber C, and the outlet is connected to the mixed gas outlet device D6; the high-temperature cracking mixed gas 8 circulates inside the heat exchange tube D2, and the normal temperature natural gas 3 and normal temperature oxygen 4 circulate outside; a plurality of baffles D3 and baffles D4 are also provided inside the raw gas heat exchange chamber D; a compensation ring D5 is provided outside the raw gas heat exchange chamber D.

[0010] Preferably, the high-temperature cracked gas 7 generated in the reaction chamber B is quenched in the cracked gas quenching chamber C to obtain a high-temperature cracked mixed gas 8, which enters the interior of the heat exchange tube D2, exchanges heat in the heat exchange tube D2 of the raw gas heat exchange chamber D, and is then discharged by the mixed gas discharge device D6; the heat exchange spaces of the normal temperature natural gas 3 and the normal temperature oxygen 4 are respectively located on both sides of the raw gas heat exchange chamber D, the inlets of the normal temperature natural gas 3 and the normal temperature oxygen 4 are located at the lower part of the raw gas heat exchange chamber D, and the outlets of the two are located at the upper part of the raw gas heat exchange chamber D; after the normal temperature natural gas 3 and the normal temperature oxygen 4 enter from the inlets respectively, they circulate outside the heat exchange tube D2 to exchange heat; the high-temperature natural gas 5 and the high-temperature oxygen 6 after the heat exchange are respectively discharged through the outlets.

[0011] An energy-saving method for preparing acetylene by partial oxidation of natural gas, preferably, the natural gas 1 and oxygen 2 are preheated separately, mixed evenly in a mixing chamber A, ignited at a burner M and enter a reaction chamber B for reaction to produce a high-temperature cracked gas 7; the high-temperature cracked gas 7 is quenched by using a normal-temperature cracked mixed gas a9 as a quenching gas; a normal-temperature synthesis gas 11 is used as a protective gas to form a protective gas curtain on the inner wall of a cracked gas quenching chamber C; the high-temperature cracked gas 7 is cooled by a four-stage cooling method to obtain a normal-temperature cracked mixed gas b10, an acetylene / synthesis gas product 12 is obtained through a separation process, and the heat in between is recycled and utilized in three stages.

[0012] Preferably, the normal temperature cracking mixed gas a9 and the normal temperature synthesis gas 11 are both products of partial oxidation of natural gas to produce acetylene, obtained by subsequent cooling and separation, and recycled; the ratio of the ejection velocity of the normal temperature cracking mixed gas a9 to the linear velocity of the high temperature cracking gas 7 is 1 to 7, and the ratio of the volume flow rate of the normal temperature cracking mixed gas a9 to the high temperature cracking gas 7 is 1 to 5, and it is ejected at the outlet of the reaction chamber B to form an annular sealing surface, and the ejection direction of the gas flow forms an angle of 80° to 165° with the flow direction of the high temperature cracking gas 7; the ratio of the ejection velocity of the normal temperature synthesis gas 11 to the linear velocity of the high temperature cracking gas 7 is 0.1 to 1.2, and the ratio of the volume flow rate of the normal temperature synthesis gas 11 to the high temperature cracking gas 7 is 0.1 to 2, and the ejection direction of the gas flow forms an angle of 30° to 90° with the center axis of the reactor downward along the wall of the reaction chamber B.

[0013] Preferably, the four-stage cooling method includes: the first-stage cooling method is to rapidly cool the high-temperature cracked gas 7 to 500-800°C by using the normal-temperature cracked mixed gas a9; the second-stage cooling method is to cool the high-temperature cracked mixed gas 8 to 300-650°C by using the normal-temperature natural gas 3 and the normal-temperature oxygen 4; the third-stage cooling method is to exchange heat between the mixed gas and the feed water 15 to 100-300°C; the fourth-stage cooling method is to cool the mixed gas to 20-80°C through the water scrubber G.

[0014] Preferably, the three-stage heat recovery and utilization includes: the first-stage recovery and utilization method is to perform gas-to-gas heat exchange between normal temperature natural gas 3 and normal temperature oxygen 4 and high temperature cracking mixed gas 8 to the required preheating temperature, and send it to the mixing chamber A; the second-stage recovery and utilization method is to perform heat exchange between the mixed gas after dust removal and feed water 15 to generate high-pressure steam 14; the third-stage recovery and utilization method is to perform heat exchange between the high-temperature carbon black water washed out by the water washing tower G and the feed water 15 through the boiler water heater H to obtain high-temperature hot water 16.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts a four-stage cooling method to cool the high-temperature cracking gas, and while effectively terminating the acetylene consumption reaction, the heat is recovered in stages, which are respectively used to heat the raw gas, generate high-pressure steam and high-temperature hot water, thereby greatly improving the utilization rate of thermal energy; using synthesis gas as the protective gas and the room-temperature cracking mixed gas as the quenching gas, without introducing new impurities, it can not only inhibit the pyrolysis carbon from undergoing heterogeneous nucleation and coking on the inner wall surface of the reactor, but also reduce the subsequent separation difficulty and compression energy consumption; the raw gas heat exchange chamber is coupled with the natural gas to acetylene reactor, with a compact structure, good heat exchange effect and saving equipment investment; high-quality carbon black is produced as a by-product, and since the dry powdered carbon black does not have strong adhesion, the process of scraping off the carbon black is simplified, and only a very small amount of carbon black water is produced, and almost no organic volatiles are produced, which is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a process flow of a device and energy-saving method for preparing acetylene by partial oxidation of natural gas provided by the present invention;

[0017] Figure 2 A schematic diagram of the structure of a reactor for producing acetylene by partial oxidation of natural gas provided by the present invention;

[0018] A-mixing chamber; B-reaction chamber; C-cracking gas quenching chamber; D-raw gas heat exchange chamber; E-dust collector; F-waste heat boiler; G-water scrubber; H-boiler water heater; I-decarbonizer; J-acetylene separation device; K1-compressor a; K2-compressor b; L1-heater a; L2-heater b; M-burner; D1-1-flange a, D1-2-flange b; D2-heat exchange tube; D3-baffle; D4-baffle; D5-compensation ring; D6-mixed gas outlet device;

[0019] 1-Natural gas; 2-Oxygen; 3-Normal temperature natural gas; 4-Normal temperature oxygen; 5-High temperature natural gas; 6-High temperature oxygen; 7-High temperature cracking gas; 8-High temperature cracking mixed gas; 9-Normal temperature cracking mixed gas a; 10-Normal temperature cracking mixed gas b; 11-Normal temperature synthesis gas; 12-Acetylene / synthesis gas product; 13-Carbon black powder; 14-High pressure steam; 15-Feed water; 16-High temperature hot water. DETAILED DESCRIPTION

[0020] The following is a detailed description of a device for preparing acetylene by partial oxidation of natural gas and an energy-saving method of the present invention in conjunction with the accompanying drawings and specific embodiments. The specific embodiments described herein are only used to explain the present invention, but the protection scope of the present invention is not limited to the embodiments.

[0021] like Figure 1 As shown, natural gas 1 and oxygen 2 are preheated by heaters respectively and fully mixed in mixing chamber A; they are ignited by burners M and enter reaction chamber B to react, producing high-temperature cracked gas 7; normal-temperature cracked mixed gas a9 is sprayed in to quench the high-temperature cracked gas 7 to obtain high-temperature cracked mixed gas 8; at the same time, normal-temperature synthesis gas 11 is sprayed in to form a protective gas curtain along the wall; the high-temperature cracked mixed gas 8 after the first-stage quenching is collected from the cracked gas quenching chamber C and distributed to the raw gas heat exchange chamber D, and normal-temperature natural gas 3 and normal-temperature oxygen 4 exchange heat with it. After reaching the preheating temperature, they are respectively discharged from the high-temperature natural gas 5 outlet and the high-temperature oxygen 6 outlet, and sent to the mixing chamber A through an insulated pipeline, and the heating of the raw gas by the heaters aL1 and bL2 is stopped; the high-temperature cracked mixed gas 8 leaves the raw gas heat exchange chamber D, and the carbon black powder 8 is filtered and collected by the dust collector E; the dedusted mixed gas passes through the waste heat boiler F and mixes with the feed water The soft water entering the inlet 15 is heat exchanged to generate high-pressure steam 14, which is discharged from the high-pressure steam outlet; the mixed gas after heat exchange enters the water washing tower G and contacts with the cooling water 15 from the top of the water washing tower G in countercurrent; high-temperature water containing a very small amount of carbon black is generated through water washing, and the high-temperature carbon black water is heated by the boiler water heater H to heat the soft water, and the obtained high-temperature hot water 16 is discharged from the outlet; the carbon black water after heat exchange is separated from the carbon black by the carbon remover I, and the carbon black is collected from the outlet after drying, and the water is merged into the water supply 15 pipeline; the room-temperature cracking mixed gas after water washing is divided into two streams, one of which is pressurized by the quenching gas circulation compressor aK1 and then sent to the cracking gas quenching chamber C as quenching gas, and the other is sent to the acetylene separation device J to obtain the acetylene / synthesis gas product 12; a part of the room-temperature synthesis gas is passed through the protective gas circulation compressor bK2 and then pressurized and sent to the cracking gas quenching chamber C as protective gas, and the other part is sent out of the boundary area as a product.

[0022] like Figure 2As shown, a burner M is arranged above the reaction chamber B to ignite the mixed gas of natural gas 1 and oxygen 2 from the mixing chamber A; the normal temperature cracking mixed gas a9 is sprayed in at high speed from the inlet to form an annular sealing surface, which rapidly cools the high temperature cracking gas 7, and the acetylene is further consumed and the reaction is terminated; the normal temperature synthesis gas 11 is sprayed in at high speed from the inlet to form a protective gas curtain to inhibit coking on the vessel wall; the high temperature cracking mixed gas 8 after the first stage of rapid cooling is collected and distributed into the raw gas heat exchange chamber D, and the high temperature cracking mixed gas 8 enters from the top and exits from the bottom along the heat exchange tube D2, and the normal temperature natural gas 3 and the normal temperature oxygen 4 enter from both sides of the raw gas heat exchange chamber D respectively, and the two raw gases are separated by the baffle D4. The heat exchange stroke and the time of passing through the raw gas heat exchange chamber D are increased by the baffle D3, and the high-temperature natural gas 5 outlet and the high-temperature oxygen 6 outlet are respectively discharged; the high-temperature cracked mixed gas 8 is discharged by the mixed gas outlet device D6 and sent to the dust collector E after secondary quenching in the raw gas heat exchange chamber D; a compensation ring D5 is provided outside the raw gas heat exchange chamber D to solve the stress caused by the different thermal expansion of the shell and the tube bundle of the raw gas heat exchange chamber D; the upper part of the raw gas heat exchange chamber D is connected to the cracked gas quenching chamber C by flange aD1-1, and the lower part is connected to the high-temperature cracked mixed gas outlet device D6 by flange bD1-2.

[0023] The external heaters for natural gas 1 and oxygen 2 are only used in the start-up phase. After continuous production, normal temperature natural gas 3 and normal temperature oxygen 4 are heated to 300-650°C by the raw gas heat exchange chamber, after which heater aL1 and heater bL2 stop heating.

[0024] Both the normal temperature cracking mixed gas a9 and the normal temperature synthesis gas 11 are products of partial oxidation of natural gas to produce acetylene, obtained by subsequent cooling and separation, and recycled; the ratio of the ejection velocity of the normal temperature cracking mixed gas a9 to the linear velocity of the high temperature cracking gas 7 is 1-7, preferably 3-5, the ratio of the volume flow rate of the normal temperature cracking mixed gas a9 to the high temperature cracking gas 7 is 1-5, preferably 2-3, and it is ejected at the outlet of the reaction chamber B to form an annular sealing surface, and the ejection direction of the gas flow forms an angle of 80°-165° with the flow direction of the high temperature cracking gas 7, preferably 80°-120°; the ejection velocity ratio of the normal temperature synthesis gas 11 to the linear velocity of the high temperature cracking gas 7 is 0.1-1.2, preferably 0.5-0.8, the ratio of the volume flow rate of the normal temperature synthesis gas 11 to the high temperature cracking gas 7 is 0.1-2, preferably 0.5-1, and the ejection direction of the gas flow forms an angle of 30°-90° with the center axis of the reactor downward along the wall of the reaction chamber B, preferably 45°-80°.

[0025] In the first stage cooling process, the room temperature cracking mixed gas a9 quenches the high temperature cracking gas 7 to 500-800°C, preferably 600-700°C; in the second stage cooling process, the room temperature natural gas 3 and the room temperature oxygen 4 cool the high temperature cracking mixed gas 8 to 300-650°C, preferably 500-650°C; in the third stage cooling process, the mixed gas is heat exchanged with water 15 to 100-300°C, preferably 150-200°C; in the fourth stage cooling process, the mixed gas is cooled to 20-80°C, preferably 30-50°C, by the water scrubber G.

[0026] In the first stage heat recovery process, normal temperature natural gas 3 and normal temperature oxygen 4 are heat exchanged with high temperature cracking mixed gas 8 to 300-650°C, preferably 500-650°C, and sent to mixing chamber A; in the second stage heat recovery process, the dust-removed high temperature cracking mixed gas 13 is heat exchanged with feed water 15 to generate high pressure steam 14; in the third stage heat recovery process, the high temperature carbon black water washed out by the water washing tower G is heat exchanged with feed water 15 through the boiler water heater H to obtain high temperature hot water 16.

[0027] Example 1

[0028] The annual production of 8,600 tons of acetylene is carried out with 3,693 kg / h of natural gas and 3,858 kg / h of oxygen as feedstock, and the volume ratio of natural gas to oxygen is 0.52:1. The natural gas and oxygen are preheated to 650°C, the reaction pressure is 1 atm, and the volume flow rate of the high-temperature cracking gas is 4.25 m 3 / s. The ejection direction of the room temperature cracking mixed gas forms a 90° angle with the flow direction of the high temperature cracking gas, the gas velocity is 120m / s, the ratio is 4:1; the volume flow rate is 12.75m 3 / s, the ratio is 3:1. The direction of the normal temperature synthesis gas is downward along the wall of the reaction chamber and forms a 45° angle with the center axis of the reactor. The gas velocity is 27m / s, the ratio is 4:1; the volume flow rate is 3.4m 3 / s, the ratio is 0.8:1. In the four-stage cooling process, the high-temperature cracking gas is rapidly cooled to 800℃ by the room-temperature mixed cracking gas, heat exchanged with the room-temperature raw gas to 650℃, heat exchanged to 300℃ by the waste heat boiler, and finally cooled to 80℃ by water washing. The maximum molar concentration of acetylene in the cracking gas is 6.8%, the unit acetylene energy consumption is reduced by 42.4%, and the unit acetylene energy consumption is reduced by 65.9% after complete energy recovery.

[0029] Example 2

[0030] The annual production of 12,000 tons of acetylene plant uses 5162 kg / h of natural gas and 6002 kg / h of oxygen as feedstock, with a volume ratio of natural gas to oxygen of 0.58:1. The natural gas and oxygen are preheated to 600°C, the reaction pressure is 1 atm, and the volume flow rate of the high-temperature cracking gas is 4.73 m 3 / s. The ejection direction of the room temperature cracking mixed gas forms a 90° angle with the flow direction of the high temperature cracking gas, the gas velocity is 90m / s, and the ratio is 3:1; the volume flow rate is 9.46m 3 / s, the ratio is 2:1. The direction of the normal temperature synthesis gas is downward along the wall of the reaction chamber, forming an angle of 45° with the center axis of the reactor, the gas velocity is 15m / s, the ratio is 31; the volume flow rate is 2.37m 3 / s, the ratio is 0.5:1. In the four-stage cooling process, the high-temperature cracking gas is rapidly cooled to 700℃ by the room-temperature mixed cracking gas, heat exchanged with the room-temperature raw gas to 600℃, heat exchanged to 200℃ by the waste heat boiler, and finally cooled to 50℃ by water washing. The maximum molar concentration of acetylene in the cracking gas is 8.5%, the unit acetylene energy consumption is reduced by 56.0%, and the unit acetylene energy consumption is reduced by 88.0% after complete energy recovery.

[0031] Example 3

[0032] The annual production of 5,000 tons of acetylene plant uses 2,294 kg / h of natural gas and 2,615 kg / h of oxygen as feedstock, with a volume ratio of natural gas to oxygen of 0.57:1. The natural gas and oxygen are preheated to 600°C, the reaction pressure is 1 atm, and the volume flow rate of the high-temperature cracking gas is 2 m 3 / s. The ejection direction of the room temperature cracking mixed gas forms a 90° angle with the flow direction of the high temperature cracking gas, the gas velocity is 90m / s, and the ratio is 3:1; the volume flow rate is 4m 3 / s, the ratio is 2:1. The direction of the spray of room temperature synthesis gas is downward along the wall of the reaction chamber, forming an angle of 45° with the center axis of the reactor, the gas velocity is 15m / s, the ratio is 3:1; the volume flow rate is 1m 3 / s, the ratio is 0.5:1. In the four-stage cooling process, the high-temperature cracking gas is rapidly cooled to 800℃ by the room-temperature mixed cracking gas, heat exchanged with the room-temperature raw gas to 600℃, heat exchanged to 250℃ by the waste heat boiler, and finally cooled to 30℃ by water washing. The maximum molar concentration of acetylene in the cracking gas is 8.4%, the unit acetylene energy consumption is reduced by 44.15%, and the unit acetylene energy consumption is reduced by 66.8% after complete energy recovery.

Claims

1. A device for preparing acetylene by partial oxidation of natural gas, characterized in that: The device for preparing acetylene by partial oxidation of natural gas comprises: a mixing chamber (A), a reaction chamber (B), a cracking gas quenching chamber (C), a raw gas heat exchange chamber (D), a dust collector (E), a waste heat boiler (F), a water scrubber (G), a boiler water heater (H), a carbon remover (I), an acetylene separation device (J), a compressor a (K1), a compressor b (K2), a heater a (L1), a heater b (L2), and a burner (M); The mixing chamber (A), the burner (M), the reaction chamber (B), the cracking gas quenching chamber (C) and the raw gas heat exchange chamber (D) are connected in sequence to form a natural gas partial oxidation to acetylene reactor; the raw gas pipeline is connected to the mixing chamber (A) inlet through the heater; the burner (M) is connected to the mixing chamber (A) outlet and the reaction chamber (B) inlet; the cracking gas quenching chamber (C) is located below the reaction chamber (B); the raw gas heat exchange chamber (D) is fixed inside the natural gas partial oxidation to acetylene reactor, and is located below the cracking gas quenching chamber (C); the raw gas heat exchange chamber (D) is provided with a normal temperature natural gas (3) inlet, a normal temperature natural gas (4) inlet, and a normal temperature natural gas (5) inlet. The oxygen (4) inlet, the high-temperature natural gas (5) outlet, and the high-temperature oxygen (6) outlet are connected to the raw gas pipeline, and the two outlets are connected to the inlet of the mixing chamber (A); the bottom of the raw gas heat exchange chamber (D) is connected to the mixed gas outlet device (D6); the outlet of the mixed gas outlet device (D6) is connected to the inlet of the dust collector (E); the outlet pipeline of the dust collector (E) is divided into two, one outlet pipeline is connected to the mixed gas inlet of the waste heat boiler (F), and the other outlet pipeline is the carbon black powder (13) product outlet; the mixed gas outlet of the waste heat boiler (F) is connected to the gas phase inlet at the bottom of the water scrubber (G); The water supply (15) pipeline is connected to the water inlet of the waste heat boiler (F), and the steam generated after heat exchange is discharged from the high-pressure steam (14) outlet of the waste heat boiler (F); the water supply (15) pipeline is connected to the cooling water inlet at the top of the water scrubber (G), and the mixed gas contacts the cooling water in countercurrent; the gas phase outlet pipeline of the water scrubber (G) is divided into two, one gas phase outlet pipeline is connected to the room temperature cracked mixed gas a (9) inlet of the cracked gas quenching chamber (C) via the compressor a (K1), and the other gas phase outlet pipeline is connected to the inlet of the acetylene separation device (J); the liquid phase outlet pipeline of the water scrubber (G) is connected to the boiler water heater (H ) product inlet pipeline; the product outlet of the boiler water heater (H) is connected to the inlet pipeline of the decarbonizer (I); the feed water (15) pipeline is connected to the water inlet of the boiler water heater (H), and is discharged from the high-temperature hot water (16) outlet after heat exchange; the solid phase outlet of the decarbonizer (I) is connected to the carbon black powder (13) outlet pipeline, and the liquid phase outlet is connected to the feed water (15) pipeline; the outlet pipeline of the acetylene separation device (J) is divided into two, one outlet pipeline is connected to the room temperature synthesis gas (11) inlet of the cracking gas quenching chamber (C) via the compressor b (K2), and the other is the acetylene / synthesis gas product outlet (12).

2. The device for preparing acetylene by partial oxidation of natural gas according to claim 1, characterized in that: A plurality of heat exchange tubes (D2) are arranged in the raw gas heat exchange chamber (D), and the inner surface of the heat exchange tube (D2) is coated with a high-temperature resistant coking inhibition coating; the inlet of the heat exchange tube (D2) is connected to the outlet of the cracking gas quenching chamber (C), and the outlet is connected to the mixed gas outlet device (D6); the high-temperature cracking mixed gas (8) flows inside the heat exchange tube (D2), and the normal temperature natural gas (3) and normal temperature oxygen (4) flow outside; the raw gas heat exchange chamber (D) is also provided with a plurality of baffles (D3) and baffles (D4); and a compensation ring (D5) is provided outside the raw gas heat exchange chamber (D).

3. The device for preparing acetylene by partial oxidation of natural gas according to claim 2, characterized in that: The high-temperature cracked gas (7) generated in the reaction chamber (B) is rapidly cooled in the cracked gas rapid cooling chamber (C) to obtain a high-temperature cracked mixed gas (8), which enters the interior of the heat exchange tube (D2), exchanges heat in the heat exchange tube (D2) of the raw gas heat exchange chamber (D), and is then discharged by the mixed gas outlet device (D6); the heat exchange spaces of the normal temperature natural gas (3) and the normal temperature oxygen (4) are respectively located on both sides of the raw gas heat exchange chamber (D), the inlets of the normal temperature natural gas (3) and the normal temperature oxygen (4) are located at the lower part of the raw gas heat exchange chamber (D), and the outlets of the two are located at the upper part of the raw gas heat exchange chamber (D); after the normal temperature natural gas (3) and the normal temperature oxygen (4) enter from the inlets respectively, they circulate outside the heat exchange tube (D2) to exchange heat; after the heat exchange, the high temperature natural gas (5) and the high temperature oxygen (6) are respectively discharged through the outlets.

4. An energy-saving method for preparing acetylene by partial oxidation of natural gas, using the device for preparing acetylene by partial oxidation of natural gas according to any one of claims 1 to 3, characterized in that: The natural gas (1) and oxygen (2) are preheated by a heater and fully mixed in a mixing chamber (A); they are ignited by a burner (M) and enter a reaction chamber (B) to react, thereby generating a high-temperature cracked gas (7); a normal-temperature cracked mixed gas a (9) is injected to rapidly cool the high-temperature cracked gas (7) to obtain a high-temperature cracked mixed gas (8); at the same time, a normal-temperature synthesis gas (11) is injected to form a protective gas curtain along the wall of the vessel; the high-temperature cracked mixed gas (8) after the first-stage rapid cooling is collected from the cracked gas rapid cooling chamber (C) and distributed to a raw gas heat exchange chamber (D); the normal-temperature natural gas (3) and the normal-temperature oxygen (4) exchange heat with the mixed gas; after reaching the preheating temperature, the mixed gas is respectively discharged from the high-temperature natural gas (5) outlet and the high-temperature oxygen (6) outlet, and is sent to the mixing chamber (A) via an insulated pipeline, and the heating of the raw gas by the heater a (L1) and the heater b (L2) is stopped; the high-temperature cracked mixed gas (8) leaves the raw gas heat exchange chamber (D), and the carbon black powder (13) is filtered and collected by the dust collector (E); the mixed gas after dust removal passes through The waste heat boiler (F) exchanges heat with the soft water entering the feed water (15) inlet to generate high-pressure steam (14), which is discharged from the high-pressure steam outlet; the mixed gas after heat exchange enters the water scrubber (G) and contacts with the cooling water from the top of the water scrubber (G) in countercurrent; high-temperature water containing a very small amount of carbon black is generated through water washing, and the high-temperature carbon black water is heated by the boiler water heater (H) to obtain high-temperature hot water (16) which is discharged from the outlet; the carbon black water after heat exchange passes through the decarbonizer (I) to separate the carbon black from the water, and the carbon black is removed from the water. After black drying, it is collected from the outlet and the water is introduced into the water supply (15) pipeline; the room temperature cracking mixed gas after water washing is divided into two streams, one of which is pressurized by the quenching gas circulation compressor a (K1) and then sent to the cracking gas quenching chamber (C) as quenching gas, and the other is sent to the acetylene separation device (J) to obtain acetylene / synthesis gas product (12); one part of the room temperature synthesis gas is introduced into the protective gas circulation compressor b (K2) and then pressurized and sent to the cracking gas quenching chamber (C) as protective gas, and the other part is sent out of the boundary area as a product.

5. The energy-saving method for preparing acetylene by partial oxidation of natural gas according to claim 4, characterized in that: The room temperature cracking mixed gas a (9) and the room temperature synthesis gas (11) are both products of partial oxidation of natural gas to produce acetylene, obtained by subsequent cooling and separation, and recycled; the ratio of the ejection velocity of the room temperature cracking mixed gas a (9) to the linear velocity of the high temperature cracking gas (7) is 1-7, the ratio of the volume flow of the room temperature cracking mixed gas a (9) to the high temperature cracking gas (7) is 1-5, and the mixed gas is ejected at the outlet of the reaction chamber (B) to form an annular sealing surface, and the ejection direction of the gas flow forms an angle of 80°-165° with the flow direction of the high temperature cracking gas (7); the ratio of the ejection velocity of the room temperature synthesis gas (11) to the linear velocity of the high temperature cracking gas (7) is 0.1-1.2, the ratio of the volume flow of the room temperature synthesis gas (11) to the high temperature cracking gas (7) is 0.1-2, and the ejection direction of the gas flow forms an angle of 30°-90° with the center axis of the reactor downward along the wall of the reaction chamber (B).

6. The energy-saving method for preparing acetylene by partial oxidation of natural gas according to claim 4, characterized in that: The high-temperature cracked gas (7) is cooled by a four-stage cooling method to obtain a room-temperature cracked mixed gas b (10); the four-stage cooling method comprises: 1) the room-temperature cracked mixed gas a (9) rapidly cools the high-temperature cracked gas (7) to 500-800°C; 2) the room-temperature natural gas (3) and the room-temperature oxygen (4) cool the high-temperature cracked mixed gas (8) to 300-650°C; 3) the mixed gas exchanges heat with feed water (15) to 100-300°C; and 4) the mixed gas is cooled to 20-80°C by a water scrubber (G).

7. The energy-saving method for preparing acetylene by partial oxidation of natural gas according to claim 4, characterized in that: Acetylene / synthesis gas product (12) is obtained through the separation process, and the heat is recycled in three stages; the three-stage heat recycling includes: 1) normal temperature natural gas (3) and normal temperature oxygen (4) are subjected to gas-to-gas heat exchange with high temperature cracking mixed gas (8) to the required preheating temperature, and then sent to the mixing chamber (A); 2) the mixed gas after dust removal is heat exchanged with feed water (15) to generate high pressure steam (14); 3) the high temperature carbon black water washed out by the water washing tower (G) is heat exchanged with feed water (15) through a boiler water heater (H) to obtain high temperature hot water (16).

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