A leak-proof storage tank for toxic liquefied gas and its use method

Abstract

The present invention belongs to the field of chemical technology, and in particular relates to a leak-proof storage tank for toxic liquefied gas and a method for using the same. The leak-proof storage tank includes a storage bin, a vacuum bin, and a negative pressure bin arranged from the inside out, and is equipped with an absorption system, which includes a fan, an absorption tower, an absorption circulation pump, and an absorption cooler. The present invention adopts a storage tank + vacuum bin + negative pressure bin design. The vacuum bin is a normalized, sealed vacuum, which solves the problem of limiting the flow of materials after the storage tank is damaged; the negative pressure bin is a normalized, atmospheric pressure bin. After a leak, the fan is started to create negative pressure, which solves the problem of limiting the flow of materials after a leak at a flange pipe or other leaking point. The leaked material is brought into the absorption system by the negative pressure. The present invention can automatically detect leaks and perform absorption treatment without the need for human contact, and the treatment is timely and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a leak-proof storage tank for toxic liquefied gas and a use method thereof. Background Art

[0002] Toxic liquefied gases, such as liquid chlorine, hydrogen fluoride, sulfur dioxide, sulfur trioxide, phosgene, hydrogen sulfide, etc., are widely used in the chemical industry. Existing equipment is often stored in steel storage tanks. Once a leak occurs, it cannot be collected. In response to this situation, regulatory authorities and individual industry associations have put forward requirements that storage tanks should be located in closed warehouses and equipped with automatic absorption devices. This method has been promoted, but the cost is generally high, and the absorption system is affected by the warehouse space. The absorbed air volume is much larger than the actual toxic gas volume, and the absorption system equipment selection is relatively large. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a leak-proof storage tank for toxic liquefied gas. The specific technical solution is as follows:

[0004] A leak-proof storage tank for toxic liquefied gas: The leak-proof storage tank includes a storage bin, a vacuum bin, and a negative pressure bin arranged from the inside outward; the storage bin is a sealed bin body made of carbon steel or alloy steel; a metal sealing jacket is tightly installed outside the storage bin, and a fan is connected to the sealing jacket to evacuate the inside to form the vacuum bin; the negative pressure bin is a sealed cabinet made of negative pressure-resistant metal plate, which encloses the storage bin and the vacuum bin;

[0005] The storage silo and vacuum silo are both fully welded, and the welds are 100% radiographically inspected. The pressure resistance requirements of the storage silo are: the internal pressure is not less than PN25 pressure level, and the external pressure is vacuum pressure resistance.

[0006] Furthermore, an SIS system liquid level instrument interface, a DCS system liquid level instrument interface, a DCS system pressure instrument interface, an absorption tower gas phase interface, a buffer tank gas phase balance interface, a nitrogen interface, a feed port, a discharge port, a manhole, and a spare port are provided on the upper part of the storage silo, and a vent pipe interface is connected to the lower part; the aforementioned interfaces are all connected from the storage silo and extend about 150 mm from the outer wall of the vacuum silo, and the interface pipes are fully welded and sealed with the storage silo and the vacuum silo, and the welds are subjected to 100% radiographic inspection; remote manual development valves are provided on the absorption tower gas phase interface and the nitrogen interface; a pressure linkage switch valve is provided on the buffer tank gas phase balance interface; one SIS system liquid level interlock switch valve and one DCS system liquid level interlock switch valve are provided on the feed port.

[0007] Furthermore, a vacuum interface is provided at the upper portion of the vacuum chamber, and a detection and analysis interface is provided at the lower portion, and internal circulation automatic detection and analysis is adopted.

[0008] Furthermore, inside the negative pressure chamber, a toxic gas detection alarm is installed above the vacuum chamber; a toxic gas detection alarm is installed below the vacuum chamber; an inspection port is opened on the upper surface of the negative pressure chamber, and an absorption fan interface is provided at the bottom of the negative pressure chamber.

[0009] Furthermore, a toxic liquefied gas inlet for the toxic liquefied gas to enter the storage tank and a toxic liquefied gas outlet for the toxic liquefied gas to exit the storage tank are set; a DCS system interlock shut-off valve, an SIS system interlock shut-off valve, a manual valve and a check valve are set in the negative pressure bin on the inlet pipeline along the flow direction; a check valve, a manual valve, an SIS system interlock shut-off valve and a DCS system interlock shut-off valve are set in the negative pressure bin on the outlet pipeline along the flow direction; the inlet pipeline and the outlet pipeline both penetrate into the bottom of the storage bin.

[0010] Furthermore, a nitrogen inlet is provided for nitrogen to enter the storage tank. A DCS system remote operation switch valve, a hand valve and a check valve are provided along the flow direction in the negative pressure bin on the nitrogen inlet pipeline. The nitrogen inlet pipeline is connected to the top of the storage bin without going deeper. The gas phase balance pipe is connected to the buffer tank. A DCS system interlock switch valve is provided along the flow direction in the negative pressure bin on the gas phase balance pipeline. The gas phase balance pipeline is connected to the top of the storage bin without going deeper. Two safety valve interfaces are provided, and the two safety valve outlets are merged into the main pipe, and the outlets of the two safety valves are connected to the absorption system out of the negative pressure bin. A hand valve is provided at the bottom of the safety valve. The safety valve pipe mouth is connected to the top of the storage bin. The manual vent pipe connects the toxic gas to the system, and a DCS system remote operation switch valve is set along the flow direction in the negative pressure bin on the manual vent pipeline. The manual vent pipeline is connected to the top of the storage bin and does not go deep; the DCS system pressure taking port, DCS system liquid level measuring port, and SIS system liquid level measuring port are respectively installed with corresponding instruments; sewage outlets are set at the bottom of the storage bin and in the negative pressure bin, and double-hand valves and blind plates are set on the sewage outlet pipeline near the pipe mouth; a circulating closed online toxic gas detector is set at the bottom of the vacuum bin, which is connected from the vacuum bin and returned to the vacuum bin.

[0011] Furthermore, two interfaces are provided on the negative pressure chamber: a gas phase outlet at the bottom, which is connected to the exhaust gas absorption system fan; and a pressure gauge interface at the top, which leads the pressure signal to the control system for interlocking control of the exhaust gas absorption system fan.

[0012] Furthermore, the storage tank is equipped with an absorption system, which includes a fan, an absorption tower, an absorption circulation pump and an absorption cooler; the fan provides negative pressure power for the negative pressure bin; the absorption tower is configured as an upper columnar tower, and the lower part is an absorbent temporary storage tank. An absorption gas inlet is arranged near the lower part of the tower, an absorption liquid inlet and an exhaust gas outlet are arranged near the upper part, and an absorption liquid outlet is arranged at the bottom; the absorption liquid outlet is connected to the absorption circulation pump; the absorption circulation pump pumps out the feed liquid into the absorption cooler to exchange heat with the circulating water. After heat exchange, the absorption liquid is connected to the absorption liquid inlet arranged at the upper part of the absorption tower.

[0013] The present invention also provides a method for using the aforementioned leak-proof storage tank for toxic liquefied gas, comprising the following steps:

[0014] Step (1): When the material is stored in the storage tank and toxic gas leaks from a possible leak point during storage and discharge, the toxic gas alarm in the negative pressure bin detects the toxic gas, alarms, and interlocks to start the fan, absorption circulation pump, and cooling water supply of the absorption cooler;

[0015] Step (2): The fan extracts the gas phase in the negative pressure chamber to the absorption tower, and begins to absorb the toxic gas using the absorbent;

[0016] Step (3): Detect the pressure on the negative pressure bin, and adjust the fan variable frequency motor through pressure interlock to maintain a slight negative pressure state in the negative pressure bin;

[0017] Step (4): The toxic gas is absorbed by the absorption tower and then discharged harmlessly.

[0018] Furthermore, the absorbent is a substance that is easily obtained and less harmful, such as low-concentration liquid alkali, water or low-concentration acid; the absorption treatment is at room temperature, and the pressure enters the absorption tower at 30 to 50 kPa. The absorbent contacts the toxic gas in reverse, and the liquid-gas ratio is controlled at 20 to 50 to fully absorb the toxic gas; a small amount of heat released during the absorption process is taken away by circulating cooling water through the absorption cooler; the negative pressure in the negative pressure chamber is maintained at -30 to 50 kPa.

[0019] The beneficial effects of the present invention are as follows: the present invention reduces the construction of closed warehouses in the original control scheme, can concentrate leakage points in the negative pressure warehouse, greatly reduces the amount of absorbed gas, reduces civil engineering costs, and also reduces equipment investment costs; at the same time, automatic control is adopted to avoid personnel exposure to toxic gas environments; the absorbent uses inexpensive low-concentration liquid alkali, water or low-concentration acid, and the operating cost is low.

[0020] This invention utilizes a storage tank + vacuum chamber + negative pressure chamber design. The vacuum chamber maintains a constant, sealed vacuum, limiting the release of materials after a tank breakage. The negative pressure chamber maintains a constant, atmospheric pressure. Upon a leak, a fan is activated to create negative pressure, limiting the release of materials from leaks at flanges, pipes, and other locations. The negative pressure draws the leaked material into the absorption system. This invention automatically detects leaks and performs absorption processing without human contact, ensuring timely, efficient, and harmless processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the present invention.

[0022] Reference numerals:

[0023] 1-Storage silo, 2-Vacuum silo, 3-Negative pressure silo; 4-Fan; 5-Absorption tower; 6-Absorption circulation pump; 7-Absorption cooler. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, a leak-proof storage tank for toxic liquefied gas: the leak-proof storage tank includes a storage bin 1, a vacuum bin 2 and a negative pressure bin 3 arranged from the inside to the outside; and a matching absorption system, which includes a fan 4, an absorption tower 5, an absorption circulation pump 6 and an absorption cooler 7.

[0026] The material storage bin is a sealed bin made of carbon steel or alloy steel; a metal sealing jacket is tightly arranged outside the material storage bin, and a fan is connected to the sealing jacket to evacuate the inside to form the vacuum bin; the negative pressure bin is a closed cabinet made of negative pressure-resistant metal plates, which wraps the material storage bin and the vacuum bin;

[0027] The storage silo and vacuum silo are both fully welded, and the welds are 100% radiographically inspected. The pressure resistance requirements of the storage silo are: the internal pressure is not less than PN25 pressure level, and the external pressure is vacuum pressure resistance.

[0028] The upper part of the storage silo is provided with an SIS system level instrument interface, a DCS system level instrument interface, a DCS system pressure instrument interface, an absorption tower gas phase interface, a buffer tank gas phase balance interface, a nitrogen interface, a feed port, a discharge port, a manhole, and a spare port, and the lower part is connected with a vent pipe interface; the aforementioned interfaces are all connected from the storage silo and extend about 150mm out of the outer wall of the vacuum chamber, the interface pipes are fully welded and sealed with the storage silo and the vacuum chamber, and the welds are subjected to 100% radiographic inspection; remote manual development valves are provided on the absorption tower gas phase interface and the nitrogen interface; a pressure linkage switch valve is provided on the buffer tank gas phase balance interface; one SIS system level interlock switch valve and one DCS system level interlock switch valve are provided on the feed port.

[0029] A vacuum interface is provided at the top of the vacuum chamber, and a detection and analysis interface is provided at the bottom, and internal circulation automatic detection and analysis is adopted. Inside the negative pressure chamber, a toxic gas detection alarm is installed at the top of the vacuum chamber; a toxic gas detection alarm is installed at the bottom of the vacuum chamber; an inspection port is provided on the top surface of the negative pressure chamber, and an absorption fan interface is provided at the bottom of the negative pressure chamber. A toxic liquefied gas inlet for entering the storage tank and a toxic liquefied gas outlet for exiting the storage tank are provided; on the inlet pipeline, a DCS system interlock shut-off valve, an SIS system interlock shut-off valve, a manual valve and a check valve are provided in the negative pressure chamber along the flow direction; on the outlet pipeline, a check valve, a manual valve, an SIS system interlock shut-off valve and a DCS system interlock shut-off valve are provided in the negative pressure chamber along the flow direction; both the inlet pipeline and the outlet pipeline extend deep into the bottom of the storage bin.

[0030] There is also a nitrogen inlet for nitrogen to enter the storage tank. On the nitrogen inlet pipeline, in the negative pressure bin, a DCS system remote operation switch valve, a hand valve and a check valve are set along the flow direction. The nitrogen inlet pipeline is connected to the top of the storage bin without going deep; the gas phase balance pipe is connected to the buffer tank. On the gas phase balance pipeline, in the negative pressure bin, a DCS system interlock switch valve is set along the flow direction. The gas phase balance pipeline is connected to the top of the storage bin without going deep; two safety valve interfaces, the two safety valve outlets are merged into the main pipe, and the negative pressure bin is connected to the absorption system; a hand valve is set at the bottom of the safety valve; the safety valve pipe mouth is connected to the top of the storage bin, Not deep; the manual vent pipe connects the toxic gas to the system, and a DCS system remote operation switch valve is set along the flow direction in the negative pressure bin on the manual vent pipeline. The manual vent pipeline is connected to the top of the storage bin and does not go deep; the DCS system pressure taking port, DCS system liquid level measuring port, and SIS system liquid level measuring port are respectively installed with corresponding instruments; sewage outlets are set at the bottom of the storage bin and in the negative pressure bin, and double-hand valves and blind plates are set on the sewage outlet pipeline near the pipe mouth; a circulating closed online toxic gas detector is set at the bottom of the vacuum bin, which is connected from the vacuum bin and returned to the vacuum bin.

[0031] Two interfaces are set on the negative pressure chamber: the gas phase outlet at the bottom is connected to the exhaust gas absorption system fan; the pressure gauge interface at the top leads the pressure signal to the control system for interlocking control of the exhaust gas absorption system fan.

[0032] The storage tank is equipped with an absorption system, which includes a fan, an absorption tower, an absorption circulation pump and an absorption cooler; the fan provides negative pressure power for the negative pressure bin; the absorption tower is configured as an upper columnar tower, and the lower part is an absorbent temporary storage tank. An absorption gas inlet is provided near the lower part of the tower, an absorption liquid inlet and an exhaust gas outlet are provided near the upper part, and an absorption liquid outlet is provided at the bottom; the absorption liquid outlet is connected to the absorption circulation pump; the absorption circulation pump pumps out the feed liquid into the absorption cooler to exchange heat with the circulating water. After heat exchange, the absorption liquid is connected to the absorption liquid inlet provided at the upper part of the absorption tower.

[0033] The method for using the aforementioned leak-proof storage tank comprises the following steps:

[0034] Step (1): When the material is stored in the storage tank and toxic gas leaks from a possible leak point during storage and discharge, the toxic gas alarm in the negative pressure bin detects the toxic gas, alarms, and interlocks to start the fan, absorption circulation pump, and cooling water supply of the absorption cooler;

[0035] Step (2): The fan extracts the gas phase in the negative pressure chamber to the absorption tower, and begins to absorb the toxic gas using the absorbent;

[0036] Step (3): Detect the pressure on the negative pressure bin, and adjust the fan variable frequency motor through pressure interlock to maintain a slight negative pressure state in the negative pressure bin;

[0037] Step (4): The toxic gas is absorbed by the absorption tower and then discharged harmlessly.

[0038] The absorbent is a substance that is easily available and less harmful, such as low-concentration liquid alkali, water or low-concentration acid; the absorption process is carried out at room temperature and a pressure of 30 to 50 kPa before entering the absorption tower. The absorbent contacts the toxic gas in reverse, and the liquid-gas ratio is controlled at 20 to 50 to fully absorb the toxic gas; a small amount of heat released during the absorption process is taken away by circulating cooling water through the absorption cooler; the negative pressure in the negative pressure chamber is maintained at -30 to 50 kPa.

[0039] The present invention can automatically detect leakage and perform absorption treatment without the need for human contact. The treatment is timely, efficient and will not endanger workers.

[0040] The above describes in detail the preferred embodiments of this patent, but this patent is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A leak-proof storage tank for toxic liquefied gas, characterized by: The leak-proof storage tank includes a storage bin, a vacuum bin and a negative pressure bin arranged from the inside out; The storage bin is a sealed bin made of carbon steel or alloy steel; a metal sealing jacket is tightly arranged outside the storage bin, and a fan is connected to the sealing jacket to evacuate the vacuum bin; The negative pressure chamber is a closed cabinet made of negative pressure resistant metal plates, which wraps the storage bin and vacuum chamber; The storage silo and vacuum silo are all made of full welding, and the welds are 100% radiographically inspected. The pressure resistance requirements of the storage silo are: the internal pressure is not less than PN25 pressure level, and the external pressure is vacuum pressure resistance; A vacuum interface is provided on the upper part of the vacuum chamber, and a detection and analysis interface is provided on the lower part, and internal circulation automatic detection and analysis is adopted; Two interfaces are set on the negative pressure chamber: the gas phase outlet at the bottom is connected to the exhaust gas absorption system fan; the pressure gauge interface at the top is used to output the pressure signal to the control system for interlock control of the exhaust gas absorption system fan; Inside the negative pressure bin, a toxic gas detection alarm is installed above the vacuum bin; a toxic gas detection alarm is installed below the vacuum bin; an inspection port is opened on the upper surface of the negative pressure bin, and an absorption fan interface is provided at the bottom of the negative pressure bin; a toxic liquefied gas inlet for entering the storage tank and a toxic liquefied gas outlet for exiting the storage tank are provided; on the inlet pipeline, a DCS system interlock shut-off valve, an SIS system interlock shut-off valve, a manual valve and a check valve are provided in the negative pressure bin along the flow direction; on the outlet pipeline, a check valve, a manual valve, an SIS system interlock shut-off valve and a DCS system interlock shut-off valve are provided in the negative pressure bin along the flow direction; the inlet pipeline and the outlet pipeline both extend deep into the bottom of the storage bin.

2. A leak-proof storage tank for toxic liquefied gas according to claim 1, characterized in that: The upper part of the storage silo is provided with an SIS system liquid level instrument interface, a DCS system liquid level instrument interface, a DCS system pressure instrument interface, an absorption tower gas phase interface, a buffer tank gas phase balance interface, a nitrogen interface, a feed port, a discharge port, a manhole, and a spare port, and the lower part is connected with a vent pipe interface; the SIS system liquid level instrument interface, the DCS system liquid level instrument interface, the DCS system pressure instrument interface, the absorption tower gas phase interface, the buffer tank gas phase balance interface, and the nitrogen interface are all connected from the storage silo and extend 150mm from the outer wall of the vacuum chamber. The interface pipes are fully welded and sealed with the storage silo and the vacuum chamber, and the welds are 100% radiographically inspected; remote manual development valves are provided on the absorption tower gas phase interface and the nitrogen interface; a pressure linkage switch valve is provided on the buffer tank gas phase balance interface; one SIS system liquid level interlock switch valve and one DCS system liquid level interlock switch valve are provided on the feed port.

3. A leak-proof storage tank for toxic liquefied gas according to claim 2, characterized in that: There is also a nitrogen inlet for nitrogen to enter the storage tank. On the nitrogen inlet pipeline, a DCS system remote operation switch valve, a manual valve and a check valve are set along the flow direction in the negative pressure bin. The nitrogen inlet pipeline is connected to the top of the storage bin without going deep; the gas phase balance pipe leads to the buffer tank, and on the gas phase balance pipeline, a DCS system interlock switch valve is set along the flow direction in the negative pressure bin. The gas phase balance pipeline is connected to the top of the storage bin without going deep; the two safety valve outlets are merged into the main pipe, and then pass into the absorption system out of the negative pressure bin; a manual valve is set at the bottom of the safety valve; the safety valve pipe mouth is connected to the top of the storage bin without going deep; the DCS system pressure taking port, the DCS system liquid level measuring port and the SIS system liquid level measuring port are respectively installed with corresponding instruments; a sewage outlet is set at the bottom of the storage bin and in the negative pressure bin; a circulating closed online toxic gas detector is set at the bottom of the vacuum bin, which is connected from the vacuum bin and returned to the vacuum bin.

4. A leak-proof storage tank for toxic liquefied gas according to claim 3, characterized in that: The storage tank is equipped with an absorption system, which includes an absorption system fan, an absorption tower, an absorption circulation pump and an absorption cooler; the absorption system fan provides negative pressure power for the negative pressure bin; the absorption tower is configured as an upper columnar tower, and the lower part is an absorbent temporary storage tank. An absorption gas inlet is provided near the lower part of the absorption tower, an absorption liquid inlet and an exhaust gas outlet are provided at the upper part of the absorption tower, and an absorption liquid outlet is provided at the bottom; the absorption liquid outlet is connected to the absorption circulation pump; the absorption circulation pump pumps out the feed liquid into the absorption cooler to exchange heat with the circulating water. After heat exchange, the absorption liquid is connected to the absorption liquid inlet provided at the upper part of the absorption tower.

5. The method for using the leak-proof storage tank for toxic liquefied gas according to claim 4, characterized in that: The steps include: Step (1): When the material is stored in the storage tank and toxic gas leaks from a possible leak point during storage and discharge, the toxic gas alarm in the negative pressure bin detects the toxic gas, alarms, and interlocks to start the absorption system fan, absorption circulation pump, and cooling water supply of the absorption cooler; Step (2): The absorption system fan extracts the gas phase in the negative pressure chamber into the absorption tower, and begins to absorb the toxic gas using the absorbent; Step (3): Detect the pressure on the negative pressure bin, and adjust the fan variable frequency motor through pressure interlock to maintain a slight negative pressure state in the negative pressure bin; Step (4): The toxic gas is absorbed by the absorption tower and then discharged harmlessly.

6. The method of use according to claim 5, characterized in that: The absorbent is low-concentration liquid alkali, water or low-concentration acid; the absorption treatment is at room temperature, the absorbent is in reverse contact with the toxic gas, and the liquid-gas ratio is controlled at 20-50 to fully absorb the toxic gas; a small amount of heat released during the absorption process is taken away by circulating cooling water through the absorption cooler.

Images