Alkane raw material treatment device and method for efficiently recycling cold energy of raw material

Abstract

The invention belongs to the technical field of alkane cracking processes, and provides an alkane raw material treatment device and method capable of efficiently recycling raw material cold energy, the alkane raw material treatment device comprises a gasification assembly, the gasification assembly comprises a throttle valve, the discharge end of the throttle valve is communicated with a cold end flow channel of a cold energy heat exchanger, and a hot end flow channel of the cold energy heat exchanger is circularly connected with a cold energy user; the gas-liquid separation assembly comprises a gas-liquid separation tank, a gas phase outlet of the gas-liquid separation tank is communicated with compression equipment, and a liquid phase outlet of the gas-liquid separation tank is communicated with a liquid alkane vaporizer; the raw material heating assembly comprises a raw material superheater, a feeding port of the raw material superheater is communicated with a discharging port of the compression equipment, and a discharging port of the raw material superheater is communicated with follow-up processing equipment. In the alkane gasification process, the alkane cooling capacity can be efficiently and stably recycled and utilized, and the purposes of reducing cost and improving efficiency can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of alkane cracking technology, and particularly relates to an alkane feedstock processing device and method for efficiently recovering the cold energy of the feedstock. Background Technology

[0002] Light hydrocarbon components such as alkanes (ethane, propane, butane) are important feedstocks for the cracking / dehydrogenation of ethylene and propylene. These alkane feedstocks, such as propane, are typically transported to the cracking unit in liquid form for initial processing. This processing mainly includes propane vaporization (from liquid to gas) and superheating. The heat source for vaporization is generally quench water (around 80°C), circulating water, or even steam, with a vaporization temperature of around 20°C. This process involves losses of heat from propane vaporization and quench water cooling (condensation). Meanwhile, olefin plants generally require large cryogenic units to provide condensation cooling, and many upstream and downstream plants in the olefin industry chain also have cooling needs, leading to increased energy consumption due to additional refrigeration costs. Currently, there is no suitable, efficient, and stable method for recovering and utilizing alkane cooling capacity. Therefore, finding a stable way to utilize the cooling capacity from feedstock vaporization is crucial to gaining an advantage in the fiercely competitive petrochemical industry. Summary of the Invention

[0003] The purpose of this invention is to provide an alkane feedstock processing device and method for efficiently recovering the cold energy of the feedstock, so as to solve the above-mentioned problems and achieve the goal of efficiently and stably recovering and utilizing the cold energy of alkane during the alkane gasification process.

[0004] To achieve the above objectives, the present invention provides the following solution: an alkane feedstock processing device for efficiently recovering the cold energy of the feedstock, comprising:

[0005] A gasification component, the gasification component including a throttle valve, the discharge end of the throttle valve being connected to the cold end flow channel of a cold energy heat exchanger, the hot end flow channel of the cold energy heat exchanger being circulatedly connected to a cold energy user.

[0006] A gas-liquid separation assembly, comprising a gas-liquid separation tank, wherein the gas phase outlet of the gas-liquid separation tank is connected to a compression device, and the liquid phase outlet of the gas-liquid separation tank is connected to a liquid alkane vaporizer.

[0007] The raw material heating assembly includes a raw material superheater, the inlet of which is connected to the outlet of the compression equipment, and the outlet of which is connected to subsequent processing equipment.

[0008] Preferably, the discharge end of the liquid alkane vaporizer is connected to the inlet of the raw material superheater.

[0009] Preferably, the liquid alkane vaporizer is connected to an alkane pipe network, or the liquid alkane vaporizer is connected to the feed end of the gas-liquid separation tank.

[0010] An alkane feedstock treatment method with high-efficiency recovery of raw material cold energy, the treatment steps comprising:

[0011] The liquid-phase alkane feedstock is depressurized by a throttle valve and then introduced into a cold energy heat exchanger to exchange heat and obtain gaseous alkane, and the medium after heat exchange in the cold energy heat exchanger is introduced into a cold energy user to exchange heat and realize recovery of cold energy.

[0012] The gaseous alkane is introduced into a gas-liquid separation tank to separate a small amount of liquid alkane entrained in the gaseous alkane.

[0013] The gaseous alkane is introduced into a compression device to be compressed to a specified pressure and then introduced into a raw material superheater to be superheated to form a raw material for subsequent treatment equipment.

[0014] Preferably, the alkane feedstock is ethane or propane or butane.

[0015] Preferably, the cold end medium of the cold energy heat exchanger is selected from any one of water, brine, ethylene glycol solution, ethylene, propylene, ethane, propane or ammonia.

[0016] Preferably, the temperature of the cold end medium of the cold energy heat exchanger is controlled at -40-20℃.

[0017] Preferably, the pressure of the gaseous alkane after the throttle valve is controlled at -00-450kPaG, and the temperature of the alkane after the throttle valve is not higher than 5℃.

[0018] Preferably, the outlet pressure of the compression device is controlled at 50-900kPaG.

[0019] Preferably, the outlet pressure of the compression device is used to provide back pressure for the liquid alkane vaporizer.

[0020] Compared with the prior art, the present application has the following advantages and technical effects: Overall, the present application sets a cold energy heat exchanger, continuously supplies alkane feedstock into the cold energy heat exchanger as a heat source, and uses heat exchange to cool, consumes part of the electric energy, and partially or completely utilizes the cold energy of the feedstock to supply one or more grades of cold energy to the device or the cold energy user upstream and downstream, greatly reduces the refrigeration cost of the device, significantly reduces the energy consumption in the production process of olefins, and achieves the purpose of reducing cost and increasing efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only constitute some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0022] Figure 1 A schematic diagram of the alkane raw material cold recovery process of the present application is shown in the figure.

[0023] In the figure, 1 is a liquid-phase alkane feed pipe; 2 is a throttle valve; 3 is a cold heat exchanger; 4 is a cold heat user; 5 is a gas-liquid separation tank; 6 is a compression device; 7 is a liquid alkane vaporizer; 8 is a gas-phase alkane feed pipe; and 9 is a raw material superheater. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0026] Embodiment one

[0027] With reference to Figure 1 The present application provides an alkane raw material processing device for efficiently recovering raw material cold, which comprises:

[0028] A gasification assembly, which comprises a throttle valve 2, the discharge end of the throttle valve 2 being communicated with the cold end flow channel of a cold heat exchanger 3, and the hot end flow channel of the cold heat exchanger 3 being cyclically connected with a cold heat user 4;

[0029] A gas-liquid separation assembly, which comprises a gas-liquid separation tank 5, the gas-phase outlet of the gas-liquid separation tank 5 being communicated with a compression device 6, and the liquid-phase outlet of the gas-liquid separation tank 5 being communicated with a liquid alkane vaporizer 7;

[0030] A raw material heating assembly, which comprises a raw material superheater 9, the feed inlet of the raw material superheater 9 being communicated with the discharge outlet of the compression device 6, and the discharge outlet of the raw material superheater 9 being communicated with subsequent processing devices.

[0031] The main function of the throttle valve 2 is to throttle and regulate the flow rate; the main function of the cold energy heat exchanger 3 is to exchange heat with the alkanes, reduce the temperature of the hot-end medium, provide cold energy to the cold energy users, and realize the recovery and utilization of cold energy; the main function of the gas-liquid separator 5 is to separate the liquid in the gasified alkanes; the main function of the compression equipment is to compress the gaseous alkanes to a specified pressure; and the main function of the raw material superheater 9 is to superheat the gaseous alkanes. Overall, this invention, by setting up a cold energy heat exchanger, continuously supplies alkane raw materials into the cold energy heat exchanger as a heat source, using heat exchange for refrigeration. By consuming some electrical energy, it partially or completely utilizes the cold energy of the raw materials to supply one or more grades of cold energy to the unit or upstream and downstream cold energy users, significantly reducing the unit's refrigeration costs. This has a significant effect on reducing energy consumption in the olefin production process, achieving the goal of cost reduction and efficiency improvement.

[0032] In a further optimized design, the feed end of the throttle valve 2 is connected to the liquid alkane feed pipe 1, and the liquid alkane is pumped into the throttle valve 2 through the liquid alkane feed pipe 1 by a delivery pump.

[0033] To further optimize the design, the feed end of the raw material superheater 9 is connected to the compression equipment 6 through the gaseous alkane feed pipe 8.

[0034] The scheme was further optimized so that the discharge end of the liquid alkane vaporizer 7 was connected to the inlet of the raw material superheater 9.

[0035] like Figure 1 As shown, the liquid alkane vaporizer 7 continues to vaporize the unvaporized alkanes in the cold heat exchanger 3 and enters the feed superheater 9 together with the gas phase from the compression device 6.

[0036] Further optimization of the scheme involves connecting the discharge end of the liquid alkane vaporizer 7 to the alkane pipeline network, or connecting the discharge end of the liquid alkane vaporizer 7 to the inlet end of the gas-liquid separator 5.

[0037] A method for efficiently recovering the cold energy of alkane feedstocks, comprising the following steps:

[0038] Liquid alkane feedstock is depressurized by throttle valve 2 and then passed into cold energy heat exchanger 3 for heat exchange to obtain gaseous alkane. At the same time, the medium after heat exchange in cold energy heat exchanger 3 enters the cold energy user for heat exchange, realizing cold energy recovery.

[0039] Gaseous alkanes enter gas-liquid separator 5 to separate a small amount of liquid alkanes entrained in the gaseous alkanes;

[0040] Gaseous alkane enters the compression device 6 and is compressed to the specified pressure. After being superheated in the raw material superheater 9, it becomes the raw material for subsequent processing equipment.

[0041] The scheme was further optimized so that the alkane feedstock could be ethane, propane, or butane.

[0042] Further optimization scheme, the cold end medium of cold heat exchanger 3 is selected from any one of water, brine, ethylene glycol solution, ethylene, propylene, ethane, propane or ammonia.

[0043] Further optimization scheme, the temperature of the cold end medium of cold heat exchanger 3 is controlled at -40-20℃, which can provide cold energy for the cold energy user 4 with a heat exchange temperature requirement of -35-35℃.

[0044] Further optimization scheme, the pressure of gaseous alkane after the throttle valve 2 is controlled at -100-450kPaG, and the temperature of alkane after the throttle valve 2 is not higher than 5℃.

[0045] Further optimization scheme, the outlet pressure of the compression device 6 is controlled at 50-900kPaG.

[0046] Further optimization scheme, the outlet pressure of the compression device 6 is used to provide back pressure for the liquid alkane vaporizer 7.

[0047] Specifically, the treatment method of the embodiment is used to prepare 150wt (million tons) of ethylene per year with propane as raw material.

[0048] The treatment amount of propane raw material in the example is 375t / h. The liquid propane raw material (2MPaG) is reduced to 305kPaG through the throttle valve 2, the gasification rate is about 15%, and the temperature is reduced to -5℃, which enters the cold heat exchanger 3 and exchanges heat with the 12℃ chilled water from the cold energy user 4, so that the temperature of the chilled water is reduced to 5℃, and the treatable chilled water is 5937t / h, which is the chilled water of the cold energy user 4. After the heat exchange of the gas-liquid two-phase propane, it is completely gasified into gaseous state, and the liquid droplets entrained are removed through the gas-liquid separation tank 5, and the gas phase enters the compression device 6 for compression, which consumes 3511kWh of electric energy, and the gaseous propane at 600kPaG is obtained, which is overheated to 50℃ through the raw material superheater 9 and then sent to the cracking unit as the cracking raw material.

[0049] At the same time, the comparative example of the embodiment provides a raw material pretreatment process for preparing 150wt (million tons) of ethylene per year with propane as raw material.

[0050] The treatment amount of propane raw material in the comparative example is 375t / h, which is sent to the propane vaporizer, and the propane vaporizer is composed of a gas-liquid separation tank and an external circulation heat exchanger. The external circulation heat exchanger uses quenching water as heat source (80℃ reduced to 50℃, 990t / h), and the completely gasified propane is obtained at the top of the gas-liquid separation tank, which is overheated to 50℃ through the superheater and then used as the ethylene cracking raw material. At the same time, the power consumption in the comparative example is 7652kWh, and 3628t / h of circulating water is consumed to prepare 7℃ chilled water for the device.

[0051] Table 1 below compares the energy utilization parameters in the example and the comparative example:

[0052] Table 1 Parameter table of Example 1 and Comparative Example 1

[0053] Utility Example 1 Comparative Example 1 Recovery cold kW 34434 (5937 t / h) 0 Compressor power consumption kWh 3511 7652 Consumption of quench water heat kW 0 34434 (990 t / h) Consumption of circulating water t / h 0 3628

[0054] From Table 1, it can be seen that, when the utility consumption of Comparative Example 1 and Example 1 is the same, the operation cost (0.2 yuan / t of circulating water, 0.6 yuan / kWh of electricity, 8000 h of operation) of Example 1 can reduce the electricity cost by 1988 million yuan / a and the circulating water energy consumption by 580 million yuan / a compared with Comparative Example 1.

[0055] Example Two:

[0056] The difference between the present example and Example One is that the processing device of the present example can contain multiple production lines in parallel. Specifically, a plurality of liquid-phase alkane feeding pipes 1 are arranged side by side, each liquid-phase alkane feeding pipe 1 is respectively connected with a group of throttles 2, each throttle 2 is respectively connected with a group of cold heat exchangers 3, each cold heat exchanger 3 is respectively connected with a group of gas-liquid separation tanks 5, and the inlet of the compression equipment 6 is correspondingly provided with a plurality of suction inlets, so that the gaseous-phase alkane of the plurality of gas-liquid separation tanks 5 enters the compression equipment 6 for compression.

[0057] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0058] The above-described examples are only preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A high-efficiency alkane feedstock processing device for recovering the cold energy of the feedstock, characterized in that, include: The gasification component includes a throttle valve (2), the outlet end of which is connected to the cold end flow channel of a cold energy heat exchanger (3), and the hot end flow channel of the cold energy heat exchanger (3) is circulatedly connected to a cold energy user (4). A gas-liquid separation assembly, comprising a gas-liquid separation tank (5), wherein the gas phase outlet of the gas-liquid separation tank (5) is connected to a compression device (6), and the liquid phase outlet of the gas-liquid separation tank (5) is connected to a liquid alkane vaporizer (7). The raw material heating assembly includes a raw material superheater (9), the inlet of which is connected to the outlet of the compression device (6), and the outlet of which is connected to a subsequent processing device.

2. The alkane feedstock processing device for high-efficiency recovery of raw material cold energy according to claim 1, characterized in that: The discharge end of the liquid alkane vaporizer (7) is connected to the inlet of the raw material superheater (9).

3. The alkane feedstock processing device for high-efficiency recovery of raw material cold energy according to claim 1, characterized in that: The discharge end of the liquid alkane vaporizer (7) is connected to the alkane pipeline network, or the discharge end of the liquid alkane vaporizer (7) is connected to the feed end of the gas-liquid separator (5).

4. A method for efficiently recovering the cold energy of alkane feedstocks, based on the apparatus for efficiently recovering the cold energy of alkane feedstocks as described in claim 1, characterized in that, The processing steps include: Liquid alkane feedstock is depressurized by throttle valve (2) and then passed into cold energy heat exchanger (3) to exchange heat and obtain gaseous alkane. At the same time, the medium after heat exchange in cold energy heat exchanger (3) enters the cold energy user for heat exchange, realizing cold energy recovery. Gas-phase alkanes enter the gas-liquid separator (5) to separate a small amount of liquid alkanes carried in the gaseous alkanes; Gaseous alkane enters the compression equipment (6) and is compressed to the specified pressure. Then it enters the raw material superheater (9) and is superheated to form the raw material for subsequent processing equipment.

5. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The alkane feedstock is ethane, propane, or butane.

6. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The cold end medium of the heat exchanger (3) is selected from any one of the following refrigerant media: water, brine, ethylene glycol solution, ethylene, propylene, ethane, propane, or ammonia.

7. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The cold end medium temperature of the heat exchanger (3) is controlled between -40 and 20°C.

8. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The pressure of the gaseous alkane after passing through the throttle valve (2) is controlled between -100 and 450 kPaG, and the temperature of the alkane after passing through the throttle valve (2) is not higher than 5°C.

9. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The outlet pressure of the compression device (6) is controlled between 50 and 900 kPaG.

10. The method for efficiently recovering the cold energy of alkane feedstock according to claim 4, characterized in that: The outlet pressure of the compression device (6) is simultaneously used to provide back pressure for the liquid alkane vaporizer (7).

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