阅读说明：本技术 常压油罐油水分离方法 (Oil-water separation method for normal pressure oil tank ) 是由 陈文武 韩磊 黄贤滨 屈定荣 于 2018-09-03 设计创作，主要内容包括：本发明涉及一种常压油罐油水分离方法,主要解决现有技术中安全性较差、污染大气的问题。本发明通过采用一种常压油罐油水分离方法,通过常压储罐、油水分离器、污水污油泵,实现储罐密闭脱水,外送污水至污水汽提装置或污水处理场,或将污油回收至储罐,实现含油污水的分级处理的技术方案较好地解决了上述问题,可用于常压油罐油水分离中。(The invention relates to an oil-water separation method for an atmospheric oil tank, which mainly solves the problems of poor safety and air pollution in the prior art. The invention adopts the technical scheme that the oil-water separation method of the normal-pressure oil tank is adopted, the sealed dehydration of the storage tank is realized through the normal-pressure storage tank, the oil-water separator and the sewage and dirty oil pump, the sewage is sent to a sewage stripping device or a sewage treatment field, or the dirty oil is recycled to the storage tank, and the classified treatment of the oily sewage is realized, so that the problems are well solved, and the method can be used for the oil-water separation of the normal-pressure oil tank.)

1. An oil-water separation method for an atmospheric oil tank comprises the following steps:

(1) for the first time

1) Removing a flange in front of a valve on the closed dehydration line, filling clear water into the oil-water separator, and recovering flange connection;

2) the normal pressure storage tank is communicated with the oil-water separator;

3) starting a sewage and dirty oil pump, delivering sewage to a sewage stripping device, gradually increasing the quantity to the maximum flow, closing the outlet of the pump to decrease the quantity when the boundary level of the field interface begins to decrease, continuously pumping until the boundary level can be judged to significantly decrease, ensuring that the storage tank is dehydrated and completely dewatered, and finishing delivering the sewage for the first time;

(2) daily operation

1) The storage tank is sealed and dehydrated, and is delivered to a sewage stripping device or a sewage treatment field through a sewage and sewage oil pump;

2) the storage tank is sealed for dehydration and is recycled to the normal pressure storage tank through a sewage and dirty oil pump and an oil return pipeline.

2. The atmospheric-pressure oil tank oil-water separation method as defined in claim 1, wherein the closed oil-water separator is installed underground, the surface of the tank is subjected to corrosion prevention treatment according to relevant specifications, dry sand is buried around the tank body, and the surface of the tank is hardened after the sand filling.

3. The oil-water separation method for the atmospheric oil tank as recited in claim 1, wherein the closed oil-water separator is provided with two sets of oil-water boundary level meters: a set of floating ball type magnetic turning plate field interface level meter and a set of dielectric constant type remote transmission liquid level meter.

4. The method for separating oil from water in an atmospheric oil tank as recited in claim 1, wherein the closed oil-water separator has an inlet connected to the closed dehydration line and two outlets: one is a dirty oil extraction port, and the other is a dirty water extraction port.

5. The method according to claim 4, wherein the dirty oil outlet is connected to a dirty oil inlet pump line, the dirty water outlet is connected to a dirty water inlet pump line, and both the dirty oil inlet pump line and the dirty water inlet pump line are connected to a dirty water pump.

6. The oil-water separation method for the normal-pressure oil tank of claim 1, wherein the storage tank is sealed for dehydration, and when the oil is delivered to a sewage stripping device or a sewage treatment field through a sewage and dirty oil pump, the operation conditions are as follows: the normal pressure storage tank needs to be dehydrated, the interface level of the oil-water separator is larger than 1600mm, materials in the normal pressure storage tank enter the oil-water separator through a closed dehydration line, and then sewage enters a pump line and a sewage-sewage pump to be decontaminated and water-steam-stripping device or a sewage treatment field; when the dehydration begins to drop obviously to the oil-water boundary, it indicates that the normal pressure storage tank is sealed and dehydrated and has oil, the dehydration is continued or the pump is stopped, and the boundary before the pump is stopped must be kept more than 1000 mm.

7. The method for separating oil from water in an atmospheric oil tank according to claim 1, wherein the storage tank is sealed for dehydration, and when the oil is recovered from the atmospheric storage tank through the sewage and dirty oil pump and the oil return pipeline, the operation conditions are as follows: the normal pressure storage tank needs dehydration, and the interface position of the oil-water separator is 1000-1600 mm; the material in the normal pressure storage tank enters an oil-water separator through a closed dehydration line, and then the dirty oil enters a pump line through the dirty oil and returns to the normal pressure storage tank through an oil return line after entering a sewage and dirty oil pump.

8. The method for separating oil from water in an atmospheric oil tank according to claim 1, wherein when the boundary level of oil and water begins to rise significantly, which means that the oil in the storage tank contains more water, and the boundary level continues to rise to approximately 1600mm, the inlet valve of the sewage and dirty oil pump is switched to the sewage inlet pump line, and after the operation is performed for 30-60 seconds, the outlet of the sewage and dirty oil pump is switched to the sewage and dirty water stripping device, and the sewage is directly sent out.

Technical Field

The invention relates to an oil-water separation method for an atmospheric oil tank.

Background

Raw materials (crude oil), intermediate raw materials (naphtha, wax oil, heavy oil, dirty oil and the like) and finished oil (gasoline, kerosene, diesel oil and the like) of oil refining enterprises are stored in various normal-pressure storage tanks (an inner floating roof tank, an outer floating roof tank, a vault tank and the like). Water is inevitably carried over into the feedstock, intermediate feedstock and finished oil as required from the production of crude oil to the petroleum processing process. The water content of crude oil, intermediate material, or product oil, which is the raw material of downstream petroleum processing equipment, is strictly controlled, and at least the water content is not contained as the basic control target. Therefore, the atmospheric tank must be subjected to a dehydration operation. At present, the dehydration method of the normal pressure storage tank mainly comprises standing manual dehydration, automatic dehydrator dehydration and other methods. However, after dehydration by any method, the wastewater enters an oily wastewater system of a tank field, is collected in a centralized manner, and then flows automatically or is lifted to a wastewater treatment device under pressure for treatment. Tank farm oily water systems are generally gravity flow systems, which are provided with inspection wells according to specifications in order to facilitate desilting after the system is silted up and blocked, and therefore, the system is not a closed system. After the oily sewage enters the system, three problems exist: firstly, oil gas and harmful substances such as sulfides possibly carried by the oil gas volatilize and enter air through a non-closed manhole cover and a leakage point of an underground pipeline, so that VOCs and toxic gas rise, peculiar smell aggravates and the environment is polluted; secondly, air can enter the system through the leakage points and is mixed with oil gas volatilized in an oil-containing sewage system (a closed system) to form explosive gas in the system, so that the potential safety hazard is huge; thirdly, the sulfur-containing sewage is directly lifted to a sewage treatment device, which may cause impact on a sewage biochemical treatment device and affect sewage treatment. Therefore, it is necessary to provide a process and a device which can remove oil and water in the atmospheric storage tank in a sealed manner and design a reasonable destination according to the properties of the oil-water mixture.

Disclosure of Invention

The invention aims to solve the technical problems of poor safety and air pollution in the prior art, and provides a novel oil-water separation method for an atmospheric oil tank, which has the advantages of good safety and no air pollution.

In order to solve the problems, the technical scheme adopted by the invention is as follows: an oil-water separation method for an atmospheric oil tank comprises the following steps:

(1) for the first time

1) Removing a flange in front of a valve on the closed dehydration line, filling clear water into the oil-water separator, and recovering flange connection;

2) the normal pressure storage tank is communicated with the oil-water separator;

3) starting a sewage and dirty oil pump, delivering sewage to a sewage stripping device, gradually increasing the quantity to the maximum flow, closing the outlet of the pump to decrease the quantity when the boundary level of the field interface begins to decrease, continuously pumping until the boundary level can be judged to significantly decrease, ensuring that the storage tank is dehydrated and completely dewatered, and finishing delivering the sewage for the first time;

(2) daily operation

1) The storage tank is sealed and dehydrated, and is delivered to a sewage stripping device or a sewage treatment field through a sewage and sewage oil pump;

2) the storage tank is sealed for dehydration and is recycled to the normal pressure storage tank through a sewage and dirty oil pump and an oil return pipeline.

In the above technical solution, preferably, the closed oil-water separator is installed underground, the surface of the tank is subjected to corrosion prevention treatment according to relevant specifications, dry sand is buried around the tank, and the surface of the ground is subjected to hardening treatment after sand filling.

In the above technical scheme, preferably, the closed oil-water separator is provided with two sets of oil-water boundary level meters: a set of floating ball type magnetic turning plate field interface level meter and a set of dielectric constant type remote transmission liquid level meter.

Among the above-mentioned technical scheme, preferably, airtight oil water separator establishes an entry, connects airtight dehydration line, two exports: one is a dirty oil extraction port, and the other is a dirty water extraction port.

Among the above-mentioned technical scheme, preferably, sump oil pump-out mouth links to each other with sump oil income pump-line, and sewage pump-out mouth links to each other with sewage income pump-line, and sump oil goes into pump-line and sewage and goes into the pump-line and all link to each other with sewage sump oil pump.

Among the above-mentioned technical scheme, preferably, the airtight dehydration of storage tank, when outwards sending to sewage stripping plant or sewage treatment field through sewage dirty oil pump, operating condition is: the normal pressure storage tank needs to be dehydrated, the interface level of the oil-water separator is larger than 1600mm, materials in the normal pressure storage tank enter the oil-water separator through a closed dehydration line, and then sewage enters a pump line and a sewage-sewage pump to be decontaminated and water-steam-stripping device or a sewage treatment field; when the dehydration begins to drop obviously to the oil-water boundary, it indicates that the normal pressure storage tank is sealed and dehydrated and has oil, the dehydration is continued or the pump is stopped, and the boundary before the pump is stopped must be kept more than 1000 mm.

Among the above-mentioned technical scheme, preferably, the airtight dehydration of storage tank, when retrieving through sewage dirty oil pump, oil return line to ordinary pressure storage tank, operating condition is: the normal pressure storage tank needs dehydration, and the interface position of the oil-water separator is 1000-1600 mm; the material in the normal pressure storage tank enters an oil-water separator through a closed dehydration line, and then the dirty oil enters a pump line through the dirty oil and returns to the normal pressure storage tank through an oil return line after entering a sewage and dirty oil pump.

Among the above-mentioned technical scheme, preferably, when the oil water boundary position begins to rise obviously, show that the storage tank oil contains more promptly, when the boundary position continues to rise to being close to 1600mm, switch sewage sump oil pump inlet valve earlier and go into the pump line to sewage, switch pump outlet again and reach sewage decontamination water stripping plant after operation 30 ~ 60 seconds, directly send out sewage.

The invention adopts a completely closed oil-water separation device to realize the dehydration operation of the normal-pressure oil tank, thereby preventing the environmental pollution and the poisoning of personnel caused by the leakage of oil gas; the hidden danger of explosion after air enters the oily sewage system is thoroughly eliminated; according to the property of the oily sewage, the classification treatment of the oily sewage is realized, the impact of the sulfur-containing sewage on the biochemical treatment of the sewage is prevented, the aims of saving energy, reducing consumption and reducing treatment cost are fulfilled, and a better technical effect is obtained.

Drawings

FIG. 1 is a schematic diagram of the closed dehydration process of the atmospheric oil tank.

The present invention will be further illustrated by the following examples, but is not limited to these examples.

Detailed Description

[ example 1 ]

An oil-water separation method for an atmospheric oil tank is shown in figure 1 and comprises an atmospheric storage tank, a closed oil-water separator, a closed dehydration line, a sewage and dirty oil pump and the like; the closed oil-water separator is characterized in that:

1. installing the tank under the ground, performing corrosion prevention treatment on the surface of the tank according to relevant specifications, burying dry sand around the tank body, and hardening the ground surface after sand filling;

2. the closed oil-water separator is horizontal, the axial diameter is 2000mm, and two sets of oil-water boundary level meters are arranged: a set of floating ball type magnetic turnover plate field boundary level meter (the field boundary level meter LG is a floating ball type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide pipe of the boundary level meter is about 300mm away from the tank bottom) and a set of dielectric constant type remote transmission liquid level meter (the remote transmission boundary level meter LI is a dielectric constant type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide rod of the boundary level meter is about 300mm away from the tank bottom);

3. this airtight oil water separator establishes an entry (airtight waterline that takes off), two exports: namely a sump oil pumping port (the distance between the bottom end and the top of the tank is 200mm) and a sewage pumping port (the distance between the bottom end and the bottom of the tank is 400 mm).

The operation steps of the closed dehydration process are as follows:

1. for the first time

(1) Removing a flange in front of the valve 4, filling clear water into the oil-water separator, and then restoring flange connection;

(2) opening the valve 1, the valve 2 and the valve 4 to communicate the normal pressure storage tank with the oil-water separator;

(3) starting a sewage and dirty oil pump, opening a valve 8, delivering sewage to a sewage stripping device, gradually opening a large valve 8 to increase the flow to the maximum flow after the flow is found, closing the outlet of a small pump to decrease the flow when a field interface metering boundary level begins to decrease, continuing pumping until the boundary level can be judged to decrease obviously, ensuring that a storage tank is dehydrated and completely removed, closing the valve to stop the pump (the boundary level decreases to indicate that the storage tank is dehydrated with oil, but the boundary level cannot be lower than 1000mm during pumping, avoiding delivering the sewage containing the oil outside), and finishing delivering the sewage for the first time.

2. Daily operation

The airtight dehydration of storage tank, oil water separator sewage pump-on outward delivery condition:

the operating conditions are as follows: the storage tank needs to be dehydrated, and the interface level of the oil-water separator is close to 1600 mm;

the materials in the normal pressure storage tank enter an oil-water separator through a closed dehydration line, and then sewage enters a pumping line and a sewage-sewage oil pump through sewage and then is removed from a sewage stripping device or a sewage treatment field.

When the dehydration begins to drop obviously to the oil-water boundary, it indicates that the normal pressure storage tank is sealed and dehydrated and has oil, the amount can be reduced to continue the dehydration or the pump is stopped, and the boundary before the pump is stopped must be kept more than 1000 mm.

[ example 2 ]

An oil-water separation method for an atmospheric oil tank is shown in figure 1 and comprises an atmospheric storage tank, a closed oil-water separator, a closed dehydration line, a sewage and dirty oil pump and the like; the closed oil-water separator is characterized in that:

1. installing the tank under the ground, performing corrosion prevention treatment on the surface of the tank according to relevant specifications, burying dry sand around the tank body, and hardening the ground surface after sand filling;

2. the closed oil-water separator is horizontal, the axial diameter is 2000mm, and two sets of oil-water boundary level meters are arranged: a set of floating ball type magnetic turnover plate field boundary level meter (the field boundary level meter LG is a floating ball type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide pipe of the boundary level meter is about 300mm away from the tank bottom) and a set of dielectric constant type remote transmission liquid level meter (the remote transmission boundary level meter LI is a dielectric constant type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide rod of the boundary level meter is about 300mm away from the tank bottom);

3. this airtight oil water separator establishes an entry (airtight waterline that takes off), two exports: namely a sump oil pumping port (the distance between the bottom end and the top of the tank is 200mm) and a sewage pumping port (the distance between the bottom end and the bottom of the tank is 400 mm).

The operation steps of the closed dehydration process are as follows:

1. for the first time

(1) Removing a flange in front of the valve 4, filling clear water into the oil-water separator, and then restoring flange connection;

(2) opening the valve 1, the valve 2 and the valve 4 to communicate the normal pressure storage tank with the oil-water separator;

(3) starting a sewage and dirty oil pump, opening a valve 8, delivering sewage to a sewage stripping device, gradually opening a large valve 8 to increase the flow to the maximum flow after the flow is found, closing the outlet of a small pump to decrease the flow when a field interface metering boundary level begins to decrease, continuing pumping until the boundary level can be judged to decrease obviously, ensuring that a storage tank is dehydrated and completely removed, closing the valve to stop the pump (the boundary level decreases to indicate that the storage tank is dehydrated with oil, but the boundary level cannot be lower than 1000mm during pumping, avoiding delivering the sewage containing the oil outside), and finishing delivering the sewage for the first time.

2. Daily operation

The airtight dehydration of storage tank, the oil water separator sump oil pump recovery condition:

the operating conditions are as follows: the storage tank needs to be dehydrated, and the interface level of the oil-water separator is lower than 1600mm and is close to 1000 mm.

The material in the normal pressure storage tank enters an oil-water separator through a closed dehydration line, and then the dirty oil enters a pump line through the dirty oil and returns to the normal pressure storage tank through an oil return line after entering a sewage and dirty oil pump.

When the oil-water boundary level begins to rise obviously, the water content of the oil product in the storage tank is high, and the boundary level continues to rise to be close to 1600mm, the inlet valve of the sewage and dirty oil pump can be switched to a sewage inlet pump line, the sewage and dirty oil pump runs for 30 seconds, then the outlet of the pump is switched to the sewage and dirty water stripping device, and the sewage is directly delivered out.

[ example 3 ]

An oil-water separation method for an atmospheric oil tank is shown in figure 1 and comprises an atmospheric storage tank, a closed oil-water separator, a closed dehydration line, a sewage and dirty oil pump and the like; the closed oil-water separator is characterized in that:

1. installing the tank under the ground, performing corrosion prevention treatment on the surface of the tank according to relevant specifications, burying dry sand around the tank body, and hardening the ground surface after sand filling;

2. the closed oil-water separator is horizontal, the axial diameter is 2000mm, and two sets of oil-water boundary level meters are arranged: a set of floating ball type magnetic turnover plate field boundary level meter (the field boundary level meter LG is a floating ball type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide pipe of the boundary level meter is about 300mm away from the tank bottom) and a set of dielectric constant type remote transmission liquid level meter (the remote transmission boundary level meter LI is a dielectric constant type, the mounting flange is 500mm away from the tank top, and the bottom end of a guide rod of the boundary level meter is about 300mm away from the tank bottom);

3. this airtight oil water separator establishes an entry (airtight waterline that takes off), two exports: namely a sump oil pumping port (the distance between the bottom end and the top of the tank is 200mm) and a sewage pumping port (the distance between the bottom end and the bottom of the tank is 400 mm).

The operation steps of the closed dehydration process are as follows:

1. for the first time

(1) Removing a flange in front of the valve 4, filling clear water into the oil-water separator, and then restoring flange connection;

(2) opening the valve 1, the valve 2 and the valve 4 to communicate the normal pressure storage tank with the oil-water separator;

(3) starting a sewage and dirty oil pump, opening a valve 8, delivering sewage to a sewage stripping device, gradually opening a large valve 8 to increase the flow to the maximum flow after the flow is found, closing the outlet of a small pump to decrease the flow when a field interface metering boundary level begins to decrease, continuing pumping until the boundary level can be judged to decrease obviously, ensuring that a storage tank is dehydrated and completely removed, closing the valve to stop the pump (the boundary level decreases to indicate that the storage tank is dehydrated with oil, but the boundary level cannot be lower than 1000mm during pumping, avoiding delivering the sewage containing the oil outside), and finishing delivering the sewage for the first time.

2. Daily operation

The airtight dehydration of storage tank, the oil water separator sump oil pump recovery condition:

the operating conditions are as follows: the storage tank needs to be dehydrated, and the interface level of the oil-water separator is lower than 1600mm and is close to 1000 mm.

The material in the normal pressure storage tank enters an oil-water separator through a closed dehydration line, and then the dirty oil enters a pump line through the dirty oil and returns to the normal pressure storage tank through an oil return line after entering a sewage and dirty oil pump.

When the oil-water boundary level begins to rise obviously, the water content of the oil product in the storage tank is high, and the boundary level continues to rise to be close to 1600mm, the inlet valve of the sewage and dirty oil pump can be switched to a sewage inlet pump line, the operation lasts for 60 seconds, then the outlet of the pump is switched to a sewage and dirty water stripping device, and the sewage is directly delivered out.

[ COMPARATIVE EXAMPLE 1 ]

One of the conventional dehydration methods for the normal-pressure storage tank is to open a water cutting valve at the bottom of the storage tank, cut water to a self-flowing oily sewage system in a tank area, stop cutting water when the water is cut visually and oil is carried, and finish a water cutting process. Thus, two problems arise: firstly, part of oil products enter a self-flowing oily sewage system along with cutting water; secondly, the cut oil-containing sewage may carry H₂S and other pollutants enter a self-flowing oily sewage system. Because the artesian oily sewage system of the oil refinery is not a completely closed system, oil products and H in the system enter with the cut oily sewage₂S and other pollutants can be volatilized into the air through the well cover and other parts to cause atmospheric pollution. Moreover, when combustible materials such as oil products are contained in the self-flowing oily sewage system, the danger of explosion and ignition is objectively existed.

[ COMPARATIVE EXAMPLE 2 ]

Dehydration of another common type of atmospheric storage tankThe method is that an automatic dehydrator is installed at the bottom of the storage tank, sewage in the oil product enters the automatic dehydrator after sedimentation, and when the water quantity reaches the dehydration liquid level, an automatic dehydration valve is automatically opened to dehydrate the sewage in the artesian oily sewage system. A small amount of emulsified oil enters the self-flowing oily sewage along with the separated sewage. Thus, two problems arise: firstly, part of oil products enter a self-flowing oily sewage system along with cutting water; secondly, the cut oil-containing sewage may carry H₂S and other pollutants enter a self-flowing oily sewage system. Because the artesian oily sewage system of the oil refinery is not a completely closed system, oil products and H in the system enter with the cut oily sewage₂S and other pollutants can be volatilized into the air through the well cover and other parts to cause atmospheric pollution. Moreover, when combustible materials such as oil products are contained in the self-flowing oily sewage system, the danger of explosion and ignition is objectively existed.