Some standard content:
1CS47.020.99
National Standard of the People's Republic of China
GB/T 17005
Impressed current cathodic protection system for coastal'structures
Issued on October 5, 1997
Implemented on August 1, 1998
Issued by the State Bureau of Technical Supervision
WGB/T17005—1997
This standard comprehensively describes the general technical requirements for impressed current cathodic protection systems for coastal facilities. Appendix B of this standard is the appendix of the standard. Appendix B of this standard is the appendix of the standard. This standard is proposed by China State Shipbuilding Corporation. This standard is issued by Luoyang Ship Material Research Institute of China State Shipbuilding Corporation. The drafting unit of this standard is Luoyang Ship Material Research Institute. East China Electric Power Design Institute, Huangbo Power Plant and Haikai Pump Co., Ltd. signed and drafted. The main drafters of this standard are Gao Shangzhu, Tong Ying, Ge Shixian, Xia Chaoju, Xu Lichong, Gong Mingbi, Liu, and Chen Huiliang. W1 Scope
National Standard of the People's Republic of China
Impressed current cathodtic protection system for coastal facilities
GB/T 17005—1997
This standard specifies the design indicators, technical requirements, system design, acceptance rules, operation and maintenance, protection effect detection, etc. of the cathodic protection system for coastal facilities.
This standard is applicable to the impressed current cathodic protection of coastal facilities such as seawater pipelines, swimming canals, condensers, and flotation reactors. It can be used as a reference for the impressed current cathodic protection of other equipment in seawater systems and facilities in water transport and high-salt water circulating water systems. 2 Reference standards
The provisions contained in the following standards are incorporated into the provisions of this standard by reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision, and the parties using this standard should consider the possibility of using the latest versions of the following standards. GE3108—82 Ship impressed current cathodic protection system GB7387--87 Technical conditions for reference electrodes for ships CB7388--87 Technical conditions for new auxiliary anodes for ships GH 7788--87
Technical conditions for the use of anode screen coatings for ships and marine floating equipment CB*3220-84 Technical requirements for constant potential instruments for ships 3 Design indicators
3.1 Equipment or systems composed of steel plates, cast rust components, auxiliary alloy pipes, stainless steel shavings, etc.: The protection potential range should reach 0.80~--1.V (for silver/silver chloride electrode, lower). The protection potential and relative relationship of commonly used reference electrodes are shown in Appendix B (shown in Appendix B). 3.2 Equipment composed of titanium and steel, cast iron, alloy and other metals; the maximum protection potential of the titanium liquid level shall not be less than -0.75V4 Technical requirements for impressed current cathodic protection system The impressed current cathodic protection system is mainly composed of auxiliary anode, anode shielding layer, reference electrode and short-term. When the company performs cathodic protection on the water pump, there should be a shaft grounding device.
4.1 Auxiliary anode
4.1.1 The performance of the auxiliary anode shall comply with the relevant requirements of GI3 7388, or a new type of anode with electrochemical performance better than that specified in the standard and technically identified shall be selected.
4.1.2 The auxiliary anode installed on the water pump, condenser end, pipeline and other facilities shall not affect the water flow and the positive belt operation of these facilities. 4.1.3 The anode of the water pump body shall adopt an embedded structure (see Figure Ci). 4.1.4 The anode installed on the boiler water chamber shall adopt the bracket type (see Figure C2) or the bracket type (see Figure C3). The anode shall be evenly distributed in the water tank to ensure uniform current distribution. Approved by the State Administration of Technology on October 5, 1997 and implemented on August 1, 1998
WCB/r 17005-1997
4.1.5 The anode installed on the bridge shall adopt the Enjian type. If the embedded type is adopted, the provisions of GB7788 shall be followed. 4.1.6 The anode installed on the floating dock shall comply with the relevant requirements of (L3108). Its installation shall be exempted from the diagram (4.4.1.7 For the buried dock, the anode shall be placed between the steel bars instead of using the ground away from the structure. 4. 1.8 For the plate resistance, it is usually necessary to balance the resistance of the steel plate with that of the steel plate, and use a separate electrode system and ground for each time. 4.2 Reference Electrode
4.2.1 The performance of the reference electrode should meet the requirements of "7387" or a new reference electrode with electrochemical performance better than that specified in the standard should be selected.
4.2.2 The reference electrode installed in the water system, steam generator, and other facilities should not affect the normal operation of these facilities. 4.2.3 Silver/silver or sample reference electrode can be used for swimming and fresh water with a resistivity of 25-100·cm. When the water medium resistivity is greater than 1cnn·cm, zinc reference electrode is used. 4.2.4 The reference electrode installed in the water system generally uses a continuous connection (with C1). 4.2. 5 The reference voltage of the condenser water can be of basic type and installed as much as possible. 4.2.6 The reference voltage installed on the pipeline can be of expansion type or cantilever type and should be installed below the lowest liquid level. 4.2.7 The reference voltage installed on the floating island should be in accordance with the relevant provisions of GB 738%-4.3 DC source
4.3.1 The medium is pure water or the conductivity and isotropy of the medium are stable, and the protected equipment is running under normal conditions, and a type regulator can be selected.
4.3-2 When one of the following conditions occurs, a constant voltage should be used. The performance of the voltage regulator meets the relevant requirements of CB*3220: 1) The water is pure water, which is greatly affected by tides and seasonal changes. 1) The equipment is running under mild conditions and the medium deceleration changes will be affected. 2) For equipment that needs to strictly control the potential. 4.4 Anode shielding layer
4.4.1 When the anode shielding layer is used in the early stage, the surrounding area should be equipped with an anode shielding layer. The raw material of the anode shielding layer should meet the requirements of (7788) or use a material with better printing performance and has passed the appraisal. 4.4.2 The size of the anode shield should make the potential distribution of the protected structure uniform. The potential of the anode shielding layer at the edge of the shielding layer will not cause damage to the coating. The size of the anode shielding layer is calculated according to formula (1) and (2). The diameter of the circular anode is 1/2 of the diameter of the thin electrode layer, 1/2/2. The output current of the anode shielding layer is ... E)/tp,)] In the formula, o-
the length of the screen cut-off edge is 1, the maximum distance between the adjacent edges is called the length of the electrode. m:
a distance closed appropriately slow D). The system spot material potential VSe
4.5 Cable
common ()
4.5.1 The cable used should be suitable for the use environment and meet the requirements of long-term use, and the most appropriate protection measures should be taken. 5.2 The cathode voltage of the cable should be sufficient to be selected and the resistance should not exceed? 2
(2)
W4. 5. 3
GB/T17005—1997.
The board cable should be a shielded cable with sufficient strength. 4.5.4 The joints between the cable and the closed electrode and between the electrode and the reference electrode should be reinforced and sealed, and protected by a sealed junction box. 4.5.5 The joints between the cable and the cathode should maintain good electrical connection and have sufficient strength. Anti-fouling treatment should be taken. 4.6 Shaft grounding device
4.6.1 The performance of the shaft grounding device should meet the relevant requirements of GB 3108. 4.6.2 The potential difference between the auxiliary grounding device and the pump body should be less than 0.06 V. 4.6.3 The electric ring is generally made of brass material and can be connected with a semicircular butt joint or a body ring structure. 4.6.4 The conductive brush is usually made of stone brush. Its performance and quality should meet the relevant requirements. Generally, two brushes are installed at the same time. If it is necessary to measure the potential difference between the shaft and the pump body, an additional brush should be installed, which should be insulated from the housing. 4.6.5 The installation position of the shaft grounding device should be selected in a dry, oil-free, and easy-to-observe and maintain location. 5 Design of impressed current protection system
5.1 Calculation of protection current
The protection current of the sensitive structure is calculated according to formula (3) I = Ers,
The protection current required for the sensitive protection structure, mA: I.-Protection current density of various materials in the protected structure under different coating conditions, mA/m\S,-Flooding area of various materials in the protected structure under different coating conditions, 5.1.1 Calculation of protection area
5.1.1.1 Calculate the flooding area of the protected structure under different materials and different coating conditions according to the geometric dimensions. 5.1.1.2 For tube bundle type equipment such as steam generators, the internal surface area of the tube protection is calculated according to formula (4). S12nd
In the formula, s-
the inner surface area of the protected tube bundle in cooling equipment such as condenser, m is the number of condenser tubes in each water layer;
d——the inner diameter of the condenser tube, m.
5.1.2 Selection of protection current density
The protection current density of various structures made of different materials shall be selected according to Table 1. Table 1 Protection current density
Material and surface treatment
Structure type
Lake water incense road||t t||Seawater pump
Net ship average
Copper and stop length
30~100
100~150
150--200
Social composite
Stainless steel
300--500
5.2 Anode size, number and arrangement
5.2.1 For the protection of water pumps, condensers and pipelines, the material and structure of the anode should be determined first, and then the size and number of the anode should be calculated.
5.2.1.1 The total effective surface area of the anode is calculated according to formula 3. S =Ii.
In the test: S.
Total effective surface area of the anode.m\;
Protective voltage, A;
WCB/T 17005—1997
i—.The working current density of the anode, A/tn. The working current density of various anodes is shown in Table 2. 5.2.1.2 The effective surface area of a single anode is calculated according to formula (6). S=./
Where: S is the effective surface of a single anode, m\: ——number of anodes,
Anode type
Lead-silver alloy
Zirconium-silver number
Platinum/nickel composite wire, plate
Platinum/titanium alloy wire, plate
2 Common anode types and their main properties in seawater Table 2
Current density, A/m3
230-350
50--180
150~45u
500--1 000
5.2.2 Number and layout of anodes
The number and layout of anodes should be based on the principle of protecting uniform current distribution. Dissipation rate
S/(A·a)
++++++++-(6 )
Good luck with unlicensed use
10--20
20--30
30~-30
5.2.2.1 For vertical seawater pumps, the number of anodes is preferably 6 to 10. 5.2.2.2 For the protection of condensers, usually 2 anodes are installed in each water chamber, and the anodes are generally installed on the water chamber cover. 5.2.2.3 For the protection of the inner wall of the pipeline, the protection potential should be reached within the anode distance range. 5.2.2.4 For the protection of floating dock, the anode spacing can be selected as 30--60m 5.3 DC power supply capacity
5.3.1 The rated output current of the DC power supply is the maximum protection current plus 1: an appropriate margin, and take an integer 5.3.2 The rated output voltage of the power supply is the product of the resistance of the entire circuit and the rated output current plus an appropriate margin, and take an integer The total circuit resistance includes:
\) The total anode water connection resistance, the single anode water connection resistance is shown in Appendix A (Standard Appendix); b) Anode voltage, which can be calculated as 5% of the anode water connection resistance: r:) The cable resistance of the entire return line.
5.3.3 The recommended constant potential instrument series is shown in Table 3. Table
5.4 Reference electrode
Output self-flowing current, A
0 ~-100
Commonly used constant potential instrument series
Output self-flowing voltage, V
0~20 or 0~ 60
0~24 or 0--60
0--24 or ~60
~2 or 0-80
0-~-24 or 0-- 6G
0--24 or 0~60
5.4.1 The types and main properties of commonly used reference electrodes are shown in Table 4. Table 4 Common reference electrode types and main properties Name
Silver oxide electrode
Zinc electrode (zinc, calcium (.7% silicon valence 16%) zinc electrode (high purity zinc 9.999%)
Copper/saturated sulfuric acid
Potential
Stability, V
Polarization potential difference
Scope of application
Seawater, sea water
Swimming water. Fresh water
Seawater, fresh water
Seawater, fresh water
AC single phase 220V.50Hz
or AC single phase 381V.50Hz
AC three phase 380V.50Hz
Use
Protective potential of steel in sea water,
0. 75-0. 95
1 0. 28 ~ -0. C0
+0. 28-~0. 00
0. 85~ 1. 05
WGB/T 170051997
5.4.2 The reference electrode should be installed near the points where the primary cell has the greatest effect, and should be kept away from the anode. 6 Acceptance Rules
6.1 Product production must be carried out in accordance with the technical requirements of this standard and related standards, with complete supporting equipment. Product performance should be strictly inspected and have a product certificate.
6.2 The construction unit must carry out construction in accordance with the design requirements. After installation, strictly check the installation quality to ensure that the auxiliary anode and reference electrode The insulation between the positive and negative electrodes should be greater than 1M under dry conditions. Ensure that the system wiring is correct (it is strictly forbidden to connect the cathode and anode in reverse). 6.3 When the impressed current cathodic protection system is put into operation, the reliability and tracking of the constant potential instrument should be checked. If the constant potential instrument does not drift and can sensitively adjust the output current value with the change of the given voltage or the potential of the protected structure, so that the potential of the structure is within the protection range, it is working properly and can be delivered for use. 7 Operation and maintenance
7.1 When the system is normal Under operation, the potential of the protected equipment, the output voltage, output current and the given potential of the constant potential meter should be recorded once every period.
7.2 When the equipment is shut down for fire maintenance, the DC power supply should be cut off, and the external current cathodic protection system should be checked: the surface condition of the anode, the surface condition of the anode shielding layer, whether there is leakage at each seal, check the damage of the anode, reference electrode, and cathode relay, record the replacement and maintenance of the anode, reference electrode, etc., clean the conductive slip ring and the carbon brush assembly. Replace the carbon brush block when necessary. 7.3 Perform comprehensive maintenance on electrical equipment such as constant potential meters. 7.4 During the equipment maintenance period, a dedicated person should be responsible for checking the external current cathodic protection system, and the removal or installation of each component in the system should be strictly in accordance with relevant requirements. After the overhaul of the equipment is completed, it will be put into normal operation in time. 8 Protection effect detection
8.1 Potential detectionwww.bzxz.net
8.1.1 For floating ships and other evenly dispersed structures, portable steel/saturated sulfur gel copper reference electrodes can be used to regularly measure the potential of the structure in the base water. The potential must meet the requirements of Section 3. 1.3.2 requirements. 8.1.2 Seawater pumps, seawater pipelines, and condenser equipment use solid reference electrodes. The protection potential can be measured by a constant potential meter or a digital multimeter, and should meet the requirements of Section 3.1.3.2. B.2 Corrosion weight loss detection
Install two sets of samples with the same material and size as the protected body, one of which is electrically connected to the protected body and the other is electrically insulated from the protected body. When the equipment is shut down for maintenance, measure the corrosion weight loss of the two sets of samples. Calculate the protection degree according to formula (7). The protection degree should be greater than 90%. = (Q - /Q × 100
Protection degree, %6
Wu Zhong: ——
Q Corrosion weight loss of insulating sample, g;
Q——Corrosion weight loss of electrically connected sample, g. 8.3 Actual observation of protection effect
Detailed inspection of the degree of rust in each part of the equipment. If there is obvious corrosion, check whether the nearby anodes are intact. If damaged, replace them in time.
For the US disc anode, calculate according to formula (A1).
For the hemispherical anode, calculate according to formula (A2).
For the cylindrical anode, calculate according to formula (A3>).
GB/T 17005-1997
Appendix A
(Appendix to the standard)
Calculation of water removal resistance of a single anode
R, = p/t2d)
R, - p!tr)
R = p[ln<41./d) - 1/(xf.)
For the strip anode, calculate according to formula (A4).
R, = pln(4L/6)/(xL)
(Lnet b)
Wu Zhong R,-
Water resistance of single anode,
Resistivity of medium.n·cml
Anode diameter+cm
Anode length cm
Anode width.rm.
Appendix B
(Requested Appendix)
...........
Determination of protective potential of steel in seawater by different reference electrodes and their mutual relationship diagram B1Determination of protective potential of steel in water by different reference electrodes and their mutual relationship diagram see B1. a
...-(Al ?
-t A2
-( A3 )
WGB/T 17005—1997
(Appendix of Prompt)
Schematic diagram of anode installation structure
Schematic diagram of embedded anode installation structure for water pump and general channel is shown in Figure C1. C1
Schematic diagram of bracket anode installation structure is shown in Figure C2. Schematic diagram of cantilever anode installation structure is shown in Figure C3. Schematic diagram of embedded anode installation structure for floating dock is shown in Figure C4. Yangbo
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Chain protection body
Figure C2
Protected body
Protective body
W cable
GB/T 17005
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