Zero-emission recovery device for boil-off gas of full-refrigeration butane storage system

Abstract

The utility model discloses a full-refrigeration butane storage system boil-off gas zero emission recovery device which comprises a full-refrigeration butane storage tank (T01) and a full-refrigeration propane storage tank (T02), and a gas phase outlet in the top of the full-refrigeration propane storage tank (T02) is connected with a propane boil-off gas condensation recovery system. A gas phase outlet in the top of the full-refrigeration butane storage tank (T01) is connected with the butane condenser (E01), a liquid phase outlet in the bottom of the butane condenser (E01) is connected with the refrigeration butane storage tank (T01), and a gas phase outlet in the top of the butane condenser (E01) is connected with a propane evaporation gas condensation recovery system. The device is simple in structure, saves energy, reduces consumption, effectively recovers non-condensable gas, and realizes'zero emission 'of butane boil-off gas.

Description

Technical Field

[0001] The utility model relates to a fully refrigerated butane and propane combined storage system, in particular to a fully refrigerated butane storage tank evaporation gas recovery device. Background Art

[0002] Large-scale fully refrigerated butane storage tanks are generally built together with fully refrigerated propane storage tanks to provide raw materials for butane isomerization units, propane dehydrogenation and other C3 and C4 comprehensive utilization projects, or to mix them into LPG for external sale as fuel.

[0003] The low-temperature butane boil-off gas (BOG) in fully refrigerated butane storage tanks contains light components such as ethane, propane, and nitrogen, which mainly comes from the following three sources: ① Residual nitrogen in the fully refrigerated butane storage tank after drying and inerting when the fully refrigerated butane storage tank is put into use for the first time; ② The fully refrigerated butane storage tank is replenished with inert nitrogen to prevent condensation in the low-temperature winter environment in the north; ③ A small amount of light hydrocarbon components such as ethane and propane are dissolved in the low-temperature butane feed.

[0004] Light non-condensable gases rapidly accumulate within the butane condenser, gradually reducing its condensing efficiency. Therefore, continuous non-condensable gas discharge is necessary to ensure efficient condensation. Due to the low operating pressure of fully refrigerated butane storage tanks (10-25 kPaG), the non-condensable gases in the butane condenser must be discharged into the flare system, preventing the effective components in the non-condensable gases from being effectively recovered and reused, resulting in significant economic losses. Furthermore, butane condensers typically utilize low-temperature propane or ambient-temperature propane throttled and vaporized at atmospheric pressure to provide cooling capacity around -40°C. After providing cooling capacity, the propane vapor is fed to the propane vapor compressor inlet of the propane vapor treatment system for recovery. This solution can easily cause the butane condensate in the butane condenser to be supercooled to below -20°C, which is below the maximum operating temperature of the fully refrigerated butane storage tank material. If the recovered supercooled butane condensate is returned to the fully refrigerated butane storage tank in large quantities for extended periods, it can compromise tank operational safety. Summary of the Invention

[0005] The purpose of the utility model is to solve the above technical problems and provide a "zero emission" recovery device for evaporated gas of a fully refrigerated butane storage system which has a simple structure, saves energy and reduces consumption, effectively recovers non-condensable gas, and achieves "zero emission" of butane evaporated gas.

[0006] The technical solution of the utility model includes a fully refrigerated butane storage tank (T01) and a fully refrigerated propane storage tank (T02), wherein the gas phase outlet at the top of the fully refrigerated propane storage tank (T02) is connected to a propane vapor condensation recovery system; the gas phase outlet at the top of the fully refrigerated butane storage tank (T01) is connected to a butane condenser (E01), the liquid phase outlet at the bottom of the butane condenser (E01) is connected to the refrigerated butane storage tank (T01), and the gas phase outlet at the top is connected to the propane vapor condensation recovery system.

[0007] Furthermore, the propane evaporated gas condensation recovery system includes a propane evaporated gas separator (V01), a propane evaporated gas compressor (K01), a propane evaporated gas condenser (E02) and a propane condensate collection tank (V02) connected in sequence. The gas phase at the top of the propane condensate collection tank (V02) is connected to the fuel gas pipeline network through a pressure reducing valve (PV01), and the liquid phase outlet at the bottom is connected to a fully refrigerated propane storage tank (T02).

[0008] Furthermore, the propane evaporated gas condensation recovery system also includes a propane economizer (E03), and the liquid phase outlet at the bottom of the propane condensate collection tank (V02) is connected to the fully refrigerated propane storage tank (T02) through the propane economizer (E03).

[0009] Furthermore, the liquid phase outlet at the bottom of the propane condensate collection tank (V02) is connected to two pipelines respectively, one pipeline is connected to the tube side inlet of the propane economizer (E03), the tube side outlet of the propane economizer (E03) is connected to the fully refrigerated propane storage tank (T02), and the other pipeline is connected to the shell side inlet of the propane economizer (E03) through the pressure reducing valve (TV02), and the shell side outlet of the propane economizer (E03) is connected to the inter-stage air supply port of the propane evaporated gas compressor (K01).

[0010] Furthermore, the gas phase outlet at the top of the butane condenser (E01) is connected to a propane evaporation gas condensation recovery system via a remote control valve (HV01).

[0011] Furthermore, the medium inlet of the butane condenser (E01) is connected to a propane pipeline provided with a pressure reducing valve (TV01), and the medium outlet of the butane condenser (E01) is connected to the inter-stage air supply port of the propane vapor compressor (K01).

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) the present invention creatively connects the gas phase outlet of the butane condenser to the propane evaporation gas condensation recovery system, and the non-condensable gas from the propane evaporation gas separator (V01) is merged into the propane evaporation gas condensation recovery system, which is pressurized and further recovered. A part of the propane and slightly heavier components of the butane non-condensable gas are merged into the propane condensate and recovered, and the other part of the light components such as ethane, propane and nitrogen that cannot be condensed are sent to the fuel gas pipeline network for recycling after being decompressed; 2) the low-temperature propane or normal pressure propane is recycled by the provided pressure reducing valve (TV01). Warm propane is throttled and evaporated in a butane condenser at a pressure of 0.2 to 0.6 MPaG, providing cooling capacity for the condensation of butane vapor. This effectively avoids the problem of butane condensate being overcooled, which is common in traditional solutions that use propane at atmospheric pressure to provide cooling capacity around -40°C. 3) The propane vapor compression and condensation system is improved. In addition to relying on the propane vapor condensation recovery system to boost and recover butane non-condensable gas, a propane economizer (E03) is installed to divide the non-condensable liquid at the bottom of the propane condensate collection tank (V02) into two streams. One condensate is supercooled in the propane economizer (E03) and then returned to the fully refrigerated propane storage tank for recovery. The other condensate is decompressed by the pressure reducing valve (TV02) and then evaporates on the shell side of the propane economizer (E03) to provide propane condensate subcooling. 4) The propane evaporated gas drawn out of the butane condenser (E01) is combined with the evaporated gas drawn out of the propane economizer E03 and sent to the inter-stage air supply port of the propane evaporated gas compressor K01. The propane evaporated gas after providing cooling capacity is recovered, which can also effectively save the operating energy consumption of the propane evaporated gas compression and condensing system, achieving multiple goals at one stroke.

[0013] The utility model has the advantages of simple structure, energy saving and consumption reduction, and effective recovery of non-condensable gas, thus achieving "zero emission" of butane evaporated gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the utility model.

[0015] Among them, there are fully refrigerated butane storage tank T01, butane condenser E01, fully refrigerated propane storage tank T02, propane evaporated gas separator tank V01, propane evaporated gas compressor K01, propane evaporated gas condenser E02, propane condensate collection tank V02, propane economizer E03, pressure reducing valve TV01, pressure reducing valve TV02, remote control valve HV01, and liquid level control valve LV01. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clearer understanding of the present invention, but they do not limit the present invention.

[0017] like Figure 1As shown, the device of the present invention includes a fully refrigerated butane storage tank T01 and a fully refrigerated propane storage tank T02. The gas phase outlet at the top of the fully refrigerated propane storage tank T02 is connected to the propane evaporated gas condensation recovery system; the gas phase outlet at the top of the fully refrigerated butane storage tank T01 is connected to the butane condenser E01, and the liquid phase outlet at the bottom of the butane condenser E01 is connected to the refrigerated butane storage tank T01, and the gas phase outlet at the top is connected to the propane evaporated gas condensation recovery system via the remote control valve HV01.

[0018] The propane evaporated gas condensation and recovery system includes a propane evaporated gas separator V01, a propane evaporated gas compressor K01, a propane evaporated gas condenser E02, a propane condensate collection tank V02 and a propane economizer E03 connected in sequence. The gas phase at the top of the propane condensate collection tank V02 is connected to the fuel gas pipeline network through a pressure reducing valve PV01, and the liquid phase outlet at the bottom is connected to two pipelines respectively, one pipeline is connected to the pipe side inlet of the propane economizer E03, the pipe side outlet of the propane economizer E03 is connected to the fully refrigerated propane storage tank T02, and the other pipeline is connected to the shell side inlet of the propane economizer E03 through a pressure reducing valve TV02, and the shell side outlet of the propane economizer E03 is connected to the inter-stage gas supply port of the propane evaporated gas compressor K01.

[0019] The medium inlet of the butane condenser E01 is connected to a propane pipeline provided with a pressure reducing valve TV01, and the medium outlet of the butane condenser E01 is connected to the inter-stage gas supply port of the propane evaporated gas compressor K01.

[0020] Process:

[0021] After the butane vapor in the fully refrigerated butane storage tank T01 enters the butane condenser E01 for condensation, the condensate flows from the bottom liquid phase outlet back to the fully refrigerated butane storage tank T01 for recovery. The butane non-condensable gas in the butane condenser E01 is drawn out through the top gas phase outlet, merged into the propane vapor gas pipeline of the fully refrigerated propane storage tank T02 through the remote control valve HV01, and sent to the propane vapor gas separator V01. At the same time, the room temperature propane or low temperature propane in the propane pipeline is reduced in pressure to 0.2-0.6 MPaG through the pressure reducing valve TV01 and sent to the butane condenser E01 to provide cooling capacity of -15℃ to -20℃ for the condensed gas, so as to control the butane condensate temperature at the outlet of the butane condenser E01 to be no lower than -20℃, effectively preventing the butane condensate from being overcooled, and then returns to the fully refrigerated butane storage tank T01 without affecting the safe operation of the fully refrigerated butane storage tank.

[0022] The non-condensable gas of the fully refrigerated propane storage tank T02 is drawn out from the top gas phase outlet and sent to the propane vapor gas separator V01 to be mixed with butane non-condensable gas. The mixed gas is then sent to the propane vapor gas compressor K01 to be pressurized to 1.4~1.8MPaG and then further condensed by the propane vapor gas condenser E02 before being sent to the propane condensate collection tank V02. Most of the propane and butane in the non-condensable gas are condensed and recovered into the propane condensate, and the remaining ethane, propane and other gas phases in the non-condensable gas are sent to the fuel gas pipeline network through the pressure reducing valve PV01 for recovery.

[0023] The condensate collected in the propane condensate collection tank V02 is split into two streams. One stream is fed through the material inlet into the propane economizer E03 for subcooling and then returns to the fully refrigerated propane storage tank T02 for recovery via the liquid level control valve LV01. The other stream is reduced to 0.2-0.6 MPaG via the pressure reducing valve TV02 and fed through the shell-side inlet into the propane economizer E03 for evaporation on the shell side, providing propane condensate subcooling. The evaporation gas from the shell-side outlet of the propane economizer E03 and the propane evaporation gas from the medium outlet of the butane condenser E01 are fed together into the interstage air supply port of the propane evaporation gas compressor K01 to recover the propane evaporation gas after providing cooling, effectively saving operating energy consumption of the propane evaporation gas compression and condensing system.

Claims

1. A "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system, comprising a fully refrigerated butane storage tank (T01) and a fully refrigerated propane storage tank (T02), characterized by: The gas phase outlet at the top of the fully refrigerated propane storage tank (T02) is connected to the propane evaporation gas condensation recovery system; the gas phase outlet at the top of the fully refrigerated butane storage tank (T01) is connected to the butane condenser (E01), the liquid phase outlet at the bottom of the butane condenser (E01) is connected to the refrigerated butane storage tank (T01), and the gas phase outlet at the top is connected to the propane evaporation gas condensation recovery system.

2. The "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system as claimed in claim 1, characterized in that: The propane vapor condensation recovery system comprises a propane vapor separator (V01), a propane vapor compressor (K01), a propane vapor condenser (E02) and a propane condensate collection tank (V02) which are connected in sequence. The gas phase at the top of the propane condensate collection tank (V02) is connected to the fuel gas network via a pressure reducing valve (PV01), and the liquid phase outlet at the bottom is connected to a fully refrigerated propane storage tank (T02).

3. The "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system as claimed in claim 2, characterized in that: The propane evaporated gas condensation recovery system further comprises a propane economizer (E03), and the liquid phase outlet at the bottom of the propane condensate collecting tank (V02) is connected to a fully refrigerated propane storage tank (T02) via the propane economizer (E03).

4. The "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system as claimed in claim 3, characterized in that: The liquid phase outlet at the bottom of the propane condensate collection tank (V02) is connected to two pipelines respectively, one pipeline is connected to the tube-side inlet of the propane economizer (E03), the tube-side outlet of the propane economizer (E03) is connected to the fully refrigerated propane storage tank (T02), and the other pipeline is connected to the shell-side inlet of the propane economizer (E03) through a pressure reducing valve (TV02), and the shell-side outlet of the propane economizer (E03) is connected to the inter-stage air supply port of the propane evaporated gas compressor (K01).

5. The "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system according to any one of claims 1 to 4, characterized in that: The gas phase outlet at the top of the butane condenser (E01) is connected to the propane evaporation gas condensation recovery system via a remote control valve (HV01).

6. The "zero emission" recovery device for boil-off gas from a fully refrigerated butane storage system according to any one of claims 2 to 4, characterized in that: The shell-side inlet of the butane condenser (E01) is connected to a propane pipeline provided with a pressure reducing valve (TV01), and the shell-side outlet of the butane condenser (E01) is connected to the inter-stage air supply port of the propane evaporation gas compressor (K01).

Images