阅读说明：本技术 临时牺牲阳极保护工艺 (Temporary sacrificial anode protection process ) 是由 逯彦伟 刘光洲 陈士强 刘菲菲 唐彪 江玉仁 于 2021-09-01 设计创作，主要内容包括：本发明公开了临时牺牲阳极保护工艺,包括以下步骤：根据储罐临时试压的介质选择牺牲阳极,基材如：铝、锌、镁、铁；根据储罐的结构与尺寸计算储罐内表面的保护面积S；根据储罐临时试压的介质选取储罐内壁保护电流密度i,本发明通过在进行水压试验的钢制石油储罐的内部网状均匀布置棒式阳极,从而保证储罐内部各个部位尽量有阳极分布,储罐内部快速达到保护的极化电位,确保临时性保护效果,从而极大的提高了钢制石油储罐的使用寿命,同时阳极采用串式结构,从而确保了阳极均布效果,并且串式结构中每串有一个或两个固定点,减少了在储罐内部固定点的安装,进而极大的避免了后期阳极拆除造成的麻烦,有利于实际的使用。(The invention discloses a temporary sacrificial anode protection process, which comprises the following steps: according to the selection of the sacrificial anode for the medium of temporary pressure test of the storage tank, the base materials are as follows: aluminum, zinc, magnesium, iron; calculating the protection area S of the inner surface of the storage tank according to the structure and the size of the storage tank; the rod type anodes are uniformly arranged in a net shape in the steel petroleum storage tank for carrying out the hydrostatic test, so that anode distribution at each part in the storage tank is ensured to be as much as possible, the polarization potential for protection is quickly reached in the storage tank, and the temporary protection effect is ensured, so that the service life of the steel petroleum storage tank is greatly prolonged.)

1. The temporary sacrificial anode protection process is characterized by comprising the following steps of:

s1, selecting a sacrificial anode material according to a medium for temporary pressure test of the storage tank;

s2, calculating the protection area S of the inner surface of the storage tank according to the structure and the size of the storage tank;

s3, selecting a protection current density i of the inner wall of the storage tank according to a medium for temporary pressure test of the storage tank;

s4, calculating the protection current I of the inner wall of the storage tank according to the actual area S of the inner wall of the protected storage tank and the selected protection current density I_{General assembly}＝Si；

S5, determining the specification and the size of the selected sacrificial anode material according to the protection current required by each storage tank and the technical requirements of the effective protection period;

s6, calculating the current value of each sacrificial anode;

s7, calculating the service life of the sacrificial anode;

s8, calculating the use amount of the sacrificial anode;

and S9, confirming the number of the anode strings according to the calculated data, and further performing anode string laying and mounting operation.

2. The temporary sacrificial anodic protection process of claim 1,the calculation formula of the protective area of the inner surface of the storage tank in the step S2 is as follows: s-pi Dh +1/2 pi D²，

Wherein S is the protected area of the inner wall of the tank bottom, D is the diameter of the tank body, and h is the height of the side wall of the protected tank body.

3. The temporary sacrificial anode protection process of claim 1, wherein the generation current value of each sacrificial anode in the step S6 is calculated by the formula: i is_a＝ΔE/R，

Where R ═ 0.315 ρ)/(va, I_aThe current generation amount of each sacrificial anode is shown, delta E is the driving potential of the sacrificial anode, R is the water resistance of the sacrificial anode, rho is the resistivity of a corrosion medium, and A is the surface area of the anode.

4. The temporary sacrificial anode protection process of claim 1, wherein the service life calculation formula of the sacrificial anode in the step S7 is as follows: y ═ o [ WQ)/(8760I_m)】1/K，

Wherein W is the net weight of each sacrificial anode, Q is the actual capacitance of the sacrificial anode, 1/K is a coefficient, 1/K is 0.8, I_m＝0.8I_aIs the amount of mean current emitted by the anode.

5. The temporary sacrificial anode protection process of claim 1, wherein the calculation formula of the sacrificial anode usage in step S8 is: n ═ I_{General assembly}/I_a。

6. The temporary sacrificial anode protection process of claim 1, wherein the laying and installing operation of the anode string in the step S9 specifically comprises the following steps:

s91, fixing the rod type anodes on the anode guy cables at equal intervals at 45 degrees to form an anode string;

s92, anode strings are laid on the bottom and the top of the inner wall of the tank body at equal intervals, two ends of each anode string are string-type anode electrical connection points and are fixed through mechanical or electric welding, each anode string is electrically connected with the tank body, and the distance between a single anode body and a protected structure is 50-100 mm;

s93, uniformly arranging fixed points of the anode strings on a circle which is 10-30 mm away from the edge of the bottom of the storage tank top through mechanical or electric welding connection;

s94, connecting cables are arranged between the bottom of the top of the storage tank and the inner wall of the tank body at equal intervals and are uniformly distributed at 45 degrees, and the two ends of each connecting cable are cable electric connecting points.

7. The temporary sacrificial anode protection process of claim 6, wherein the electrical connection points of the anode string in the step S92 are connected by electric welding or bolt fastening.

8. The temporary sacrificial anode protection process of claim 6, wherein the anode string at the bottom of the tank top in the step S93 is fixed by bolts.

9. The temporary sacrificial anode protection process of claim 6, wherein the cable electrical connection points in the step S94 are connected using thermite welding or manual arc welding.

Technical Field

The invention belongs to the field of anode protection, and particularly relates to a temporary sacrificial anode protection process.

Background

In the existing life, the steel storage tank engineering is an indispensable and important infrastructure in the industries of petroleum, chemical engineering, grain and oil, food, fire control, traffic, metallurgy, national defense and the like, the steel storage tank with large and small sizes cannot be opened in the economic life of people, and the steel storage tank plays an important role in the national economic development and is not replaceable. With the continuous development of the storage tank industry, more and more industries and enterprises use the storage tank, more and more enterprises enter the storage tank industry, the steel storage tank is a special device for storing various liquid raw materials and finished products, the storage tank can not be normally produced for many enterprises without the storage tank, particularly, storage tanks with various capacities and types can not be reserved for national strategic materials, oil storage facilities in China mainly comprise overground storage tanks, metal structures are more, and the steel petroleum storage tank is often used for storing petroleum in the commercial storage of crude oil.

However, when the existing steel oil storage tank is put into use formally, the medium which is convenient to obtain needs to be adopted to carry out a hydrostatic test on the inner wall of the storage tank, and the steel structure of the inner wall of the steel oil storage tank has a large demand on protective current during the period, so that if protective measures are lacked, the service life of the steel oil storage tank is shortened, and the steel oil storage tank is not beneficial to actual use.

The invention content is as follows:

the present invention has been made to solve the above problems, and an object of the present invention is to provide a temporary sacrificial anode protection process.

In order to solve the above problems, the present invention provides a technical solution:

the temporary sacrificial anode protection process comprises the following steps:

s1, selecting a sacrificial anode material according to a medium for temporary pressure test of the storage tank;

s2, calculating the protection area S of the inner surface of the storage tank according to the structure and the size of the storage tank;

s3, selecting a protection current density i of the inner wall of the storage tank according to a medium for temporary pressure test of the storage tank;

s4, pressCalculating the protection current I of the inner wall of the storage tank according to the actual area S of the inner wall of the protected storage tank and the selected protection current density I_{General assembly}＝Si；

S5, determining the specification and the size of the selected sacrificial anode material according to the protection current required by each storage tank and the technical requirements of the effective protection period;

s6, calculating the current value of each sacrificial anode;

s7, calculating the service life of the sacrificial anode;

s8, calculating the use amount of the sacrificial anode;

and S9, confirming the number of the anode strings according to the calculated data, and further performing anode string laying and mounting operation.

Preferably, the calculation formula of the protective area of the inner surface of the storage tank in the step S2 is as follows: s-pi Dh +1/2 pi D²，

Wherein S is the protected area of the inner wall of the tank bottom, D is the diameter of the tank body, and h is the height of the side wall of the protected tank body.

Preferably, the generation current value of each sacrificial anode in step S6 is calculated by the formula: i is_a＝ΔE/R，

Where R ═ 0.315 ρ)/(va, I_aThe current generation amount of each sacrificial anode is shown, delta E is the driving potential of the sacrificial anode, R is the water resistance of the sacrificial anode, rho is the resistivity of a corrosion medium, and A is the surface area of the anode.

Preferably, the formula for calculating the service life of the sacrificial anode in step S7 is as follows: y ═ o [ WQ)/(8760I_m)】1/K，

Wherein W is the net weight of each sacrificial anode, Q is the actual capacitance of the sacrificial anode, 1/K is a coefficient, 1/K is 0.8, I_m＝0.8I_aIs the amount of mean current emitted by the anode.

Preferably, the formula for calculating the sacrificial anode usage in step S8 is: n ═ I_{General assembly}/I_a。

Preferably, the laying and mounting operation of the anode string in step S9 specifically includes the following steps:

s91, fixing the rod type anodes on the anode guy cables at equal intervals at 45 degrees to form an anode string;

s92, anode strings are laid on the bottom and the top of the inner wall of the tank body at equal intervals, two ends of each anode string are string-type anode electrical connection points and are fixed through mechanical or electric welding, each anode string is electrically connected with the tank body, and the distance between a single anode body and a protected structure is 50-100 mm;

s93, uniformly arranging fixed points of the anode strings on a circle which is 10-30 mm away from the edge of the bottom of the storage tank top through mechanical or electric welding connection;

s94, connecting cables are arranged between the bottom of the top of the storage tank and the inner wall of the tank body at equal intervals and are uniformly distributed at 45 degrees, and the two ends of each connecting cable are cable electric connecting points.

Preferably, the electrical connection points of the anode string in step S92 are connected by electric welding or bolt fastening.

Preferably, in step S93, the anode string at the bottom of the tank top is fixed by bolts.

Preferably, the electrical connection point of the cable in the step S94 is connected by thermite welding or manual arc welding.

The invention has the beneficial effects that: the rod type anodes are uniformly arranged in the steel petroleum storage tank for the hydrostatic test in a net shape, so that the anode distribution at each part in the storage tank is ensured as much as possible, the protected polarization potential is quickly reached in the storage tank, the temporary protection effect is ensured, the service life of the steel petroleum storage tank is greatly prolonged, meanwhile, the anodes adopt a string type structure, so that the anode uniform distribution effect is ensured, one or two fixed points are arranged in each string in the string type structure, the installation of the fixed points in the storage tank is reduced, the trouble caused by later anode dismantling is greatly avoided, and the practical use is facilitated.

Description of the drawings:

for ease of illustration, the invention is described in detail by the following detailed description and the accompanying drawings.

FIG. 1 is a schematic view of the installation of a sacrificial anode on a tank wall according to the present invention;

FIG. 2 is a cross-sectional view taken along A-A of FIG. 1;

FIG. 3 is a schematic view of the inner wall protection of the storage tank of the present invention;

FIG. 4 is a schematic view of the first anode string and floating plate of the present invention;

FIG. 5 is a schematic view of the bottom of the inner wall of the storage tank and the bottom protection of the floating plate according to the present invention;

FIG. 6 is a schematic view of an aluminum bar assembly structure according to the present invention.

In the figure: 1. a storage tank; 2. the storage tank is topped; 3. connecting a cable; 4. a cable electrical connection point; 5. a first anode string; 6. a second anode string; 7. an anode electrical connection point; 8. a rod anode.

The specific implementation mode is as follows:

as shown in fig. 1 to 6, the following technical solutions are adopted in the present embodiment:

example (b):

the temporary sacrificial anode protection process comprises the following steps:

s1, selecting a sacrificial anode material according to a medium for temporary pressure test of the storage tank;

s2, calculating the protection area S of the inner surface of the storage tank according to the structure and the size of the storage tank;

s3, selecting a protection current density i of the inner wall of the storage tank according to a medium for temporary pressure test of the storage tank;

s4, calculating the protection current I of the inner wall of the storage tank according to the actual area S of the inner wall of the protected storage tank and the selected protection current density I_{General assembly}＝Si；

S5, determining the specification and the size of the selected sacrificial anode material according to the protection current required by each storage tank and the technical requirements of the effective protection period;

s6, calculating the current value of each sacrificial anode;

s7, calculating the service life of the sacrificial anode;

s8, calculating the use amount of the sacrificial anode;

and S9, confirming the number of the anode strings according to the calculated data, and further performing anode string laying and mounting operation.

Further, the calculation formula of the protective area of the inner surface of the storage tank in the step S2 is as follows: s-pi Dh +1/2 pi D²，

Wherein S is the protected area of the inner wall of the tank bottom, D is the diameter of the tank body, and h is the height of the side wall of the protected tank body.

Further, the generation current value of each sacrificial anode in step S6 is calculated by the formula: i is_a＝ΔE/R，

Where R ═ 0.315 ρ)/(va, I_aThe current generation amount of each sacrificial anode is shown, delta E is the driving potential of the sacrificial anode, R is the water resistance of the sacrificial anode, rho is the resistivity of a corrosion medium, and A is the surface area of the anode.

Further, the formula for calculating the service life of the sacrificial anode in step S7 is as follows: y ═ o [ WQ)/(8760I_m)】1/K，

Wherein W is the net weight of each sacrificial anode, Q is the actual capacitance of the sacrificial anode, 1/K is a coefficient, 1/K is 0.8, I_m＝0.8I_aIs the amount of mean current emitted by the anode.

Further, the calculation formula of the sacrificial anode usage in step S8 is as follows: n ═ I_{General assembly}/I_a。

Further, the laying and mounting operation of the anode string in the step S9 specifically includes the following steps:

s91, fixing the rod type anodes on the anode guy cables at equal intervals at 45 degrees to form an anode string;

s92, anode strings are laid on the bottom and the top of the inner wall of the tank body at equal intervals, two ends of each anode string are string-type anode electrical connection points and are fixed through mechanical or electric welding, each anode string is electrically connected with the tank body, and the distance between a single anode body and a protected structure is 50-100 mm;

s93, uniformly arranging fixed points of the anode strings on a circle which is 10-30 mm away from the edge of the bottom of the storage tank top through mechanical or electric welding connection;

s94, connecting cables are arranged between the bottom of the top of the storage tank and the inner wall of the tank body at equal intervals and are uniformly distributed at 45 degrees, and the two ends of each connecting cable are cable electric connecting points.

Further, the electrical connection point of the anode string in the step S92 is connected by welding or bolt fastening.

Further, the anode string at the bottom of the top of the storage tank in the step S93 is fixed by bolts.

Further, in the step S94, the electric connection point of the cable is connected by thermite welding or manual arc welding.

Specifically, the method comprises the following steps: in actual practice, one hundred thousand cubic tanks were used during the hydrostatic test, test medium: natural seawater with the diameter phi of 80m and the quantity of 12 is selected, firstly, an aluminum alloy sacrificial anode material is selected, the design protection range is that a storage tank floating disc and the inner wall of a bottom plate and the vertical inner wall of a storage tank are adopted, the protection technical index is designed, an effective protector is designed for 60 days, the protection potential of the inner wall of the protected storage tank is between-0.85V and-1.10V in the effective protection period, and compared with a Cu/saturated CuSO4 reference electrode, the cathode protection system needs to be ensured to operate safely and reliably in the effective protection period, and then the storage tank inner wall cathode protection can be designed:

firstly, selecting a sacrificial anode material, wherein the sacrificial anode material mainly comprises zinc alloy, aluminum alloy, magnesium alloy and the like, the zinc alloy anode is easy to have polarity reversal and low cost performance at high temperature, and the magnesium alloy anode has negative potential and is too fast to be consumed when placed in seawater; the aluminum alloy sacrificial anode has the characteristics of large current magnitude and stable performance, can be used for cathodic protection of the inner wall of the storage tank, adopts the aluminum alloy sacrificial anode with good solubility and strong adaptability in a medium of natural seawater during a test to protect the inner wall of the storage tank, and has the electrochemical properties shown in the following table:

and then calculating the protection area S of the inner surface of the storage tank according to the structure and the size of the storage tank, wherein S is pi Dh +1/2 pi D²Wherein S is the protected area of the inner wall of the tank bottom and is m²D is the diameter of the tank body, the unit m, h is the height of the side wall of the protected tank body, h is 20.2m, and the protection area of the inner wall of each hundred thousand cubic storage tanks is calculated to be S which is 15122.24m²。

Then selecting the inner wall of the storage tank to protect the electricityFlow density i 95mA/m²；

Calculating the protection current I of the inner wall of the storage tank according to the actual area S of the inner wall of the protected storage tank and the selected protection current density I_{General assembly}＝Si＝1436.6128A；

According to the protection current required by each storage tank and the technical requirement of 60 days of effective protection period, the specification size of the selected aluminum alloy sacrificial anode material is determined to be phi 20 multiplied by 500mm, and the net weight of each anode is 0.42 kg;

calculating the current value, I, of each sacrificial anode_aΔ E/R, where R ═ 0.315 ρ)/(va, I_aSubstituting the relevant data into the formula to obtain the generation current Ia of the selected sacrificial anode which is 0.565A/block, wherein the generation current is of each sacrificial anode, delta E is the driving potential of the sacrificial anode, delta E is 0.25V, R is the water-receiving resistance of the sacrificial anode, rho is the resistivity of a corrosion medium, rho is 25 omega cm, and A is the surface area of the anode;

the service life of the sacrificial anode was calculated, Y ═ W (WQ)/(8760I)_m) 1/K, where W is the net weight of each sacrificial anode, Q is the actual capacitance of the sacrificial anode, 1/K is a coefficient, 1/K is 0.8, I_mThe amount of mean current emitted by the anode, I_m＝(0.6～0.8)I_aSubstituting the relevant data into Y ═ W (WQ)/(8760I)_m) 1/K, obtaining that Y is 0.203 years, namely 74 days, so that the service life of the sacrificial anode meets the use requirement of engineering design;

calculating the consumption of sacrificial anode, N ═ I_{General assembly}/I_aThe number of the anodes on the inner wall of the hundred thousand cubic storage tank is 2543, and 2550 anodes are selected for uniform arrangement;

the anode string laying and installation operation is carried out according to the calculated data, firstly, aluminum bars are welded on the anode guy cable at equal intervals to form the anode string, as shown in figure 6, then anode strings are laid on the bottom of the inner wall of the tank body and the bottom of the floating disc at equal intervals, the two ends of each anode string are aluminum anode electrical connection points, the aluminum anode electrical connection points are connected by adopting an electric welding or bolt fastening method, meanwhile, each anode string is ensured to be electrically connected with the tank body, the installation modes of the bottom of the inner wall of the tank body and the bottom of the floating plate are all shown in figure 5, then an anode string is arranged at the bottom of the floating plate, the anode string at the bottom of the floating plate is fixed by using M10 galvanized bolts, as shown in figures 3 and 4, then connecting cables are arranged between the top of the floating disc and the inner wall of the tank body at equal intervals and are uniformly distributed at 45 degrees, as shown in fig. 3, the two ends of the connecting cable are cable electrical connection points, and the cable electrical connection points are connected by thermite welding or manual arc welding.

Adopt above-mentioned technology to protect the steel oil storage tank, evenly arrange the positive pole through the inside at the steel oil storage tank, thereby guarantee that every bare steel has the positive pole to distribute as far as possible, can ensure interim protection effect, thereby very big improvement the life of steel oil storage tank, the positive pole adopts the string formula structure simultaneously, thereby the positive pole equipartition effect has been ensured, and every cluster has one or two fixed welding spots in the string formula structure, the installation of solder joint has been reduced, and then very big has avoided the trouble that later stage positive pole demolishs and causes, be favorable to actual use.

In the description of the present invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inner", "front", "center", "both ends", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second", "third", "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby the features defined as "first", "second", "third", "fourth" may explicitly or implicitly include at least one such feature.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "disposed," "connected," "secured," "screwed" and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; the terms may be directly connected or indirectly connected through an intermediate, and may be communication between two elements or interaction relationship between two elements, unless otherwise specifically limited, and the specific meaning of the terms in the present invention will be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.