Course project - Development of cathodic protection station

Contents

Introduction

1. Design and processing part

1.1. Characteristics of gas pipeline (LPG tank)

1.2. Calculation of specific weight of pipelines and determination of protective current density

1.3 Design Cathodic Protection Calculation

1.3 Design Tread Protection Calculation

1.5 Economic calculation of cathodic protection of the project

1.6 Project Tread Protection Economic Calculation

2. Organizational and Economic Part

2.1 Comparative analysis of protection types

2.2 Feasibility study of selected type of protection

3. Operational part

3.1 Operation of gas pipelines (LPG tanks)

3.2 Operation of protective installations

3.3 Occupational Safety and Safety

Introduction

Metal corrosion is called gradual surface destruction of metals as a result of chemical and electrochemical interaction of the external surfaces of underground steel pipelines. Such damage occurs due to the interaction of the pipe metals with chemical compounds present in the soil and wandering electric currents. Corrosion control usually consists of removing corrosive substances from the gas in its cleaning and increasing the requirements for the amount of gas transported. Distinguish between soil (electrochemical) corrosion and corrosion with vagus currents.

Main factors determining soil corrosion:

The type of soil, the composition and concentration of soluble substances in it, humidity, the nature of air penetration, the structure, the presence of bacteria activating corrosion processes, temperature and resistivity of the soil. The risk of soil corrosion of underground metal structures is determined by the corrosive activity of the soil in relation to the metal from which these structures are made.

Corrosion activity of soil in relation to carbon steel of underground metal structures is estimated by three parameters:

1. specific electrical resistance of soils;

2. loss of sample weight;

3. polarizing current density.

All steel underground gas pipelines shall be protected against soil corrosion and causing wandering currents. Corrosion protection should be designed in accordance with the requirements of GOST 9.01574 * "Unified protection system for corrosion and aging of the underground structure. General technical requirements. " SNiP 2040887 "Gas Supply" "Safety Rules for Operation of Electrical Installations of Consumers" "Safety Rules for Gas Facilities."

Measures to protect underground gas pipelines under construction from corrosion are provided by the project, which includes electrochemical protection. These measures should be carried out before putting the gas pipeline into operation, but not later than six months after laying the gas pipeline in the ground.

Soil corrosion protection means are selected on the basis of gas pipeline laying conditions and data on corrosive activity of medium (soil and ground water) in relation to pipeline metals taking into account the results of technical and economic calculations.

Corrosion protection projects shall be developed simultaneously with gas pipeline design by the same design organization.

The methods of protection of underground gas pipelines against corrosion of both types (soil and caused by wandering currents) mainly coincide: this is a rational choice of the route of gas pipelines and underground communication cables and the corresponding protective coating design that best meets operating conditions.

Operational part

3.1Operating gas pipelines

During technical operation of gas distribution systems, comply with the requirements of PB 12529, PB 12609, PB 10115 and other regulatory acts approved in the established manner, as well as the requirements of OST 15339,30512003. During operation of the gas-using equipment, the requirements of the operational documentation of the manufacturers should be observed.

Emergency maintenance of gas distribution networks is carried out around the clock by ADS GRO or (if there is no function for gas flow distribution) by the emergency gas service of the operational organization.

Organization of technical operation

During technical operation of gas distribution systems facilities the following types of works are performed:

- technical supervision of construction;

- connection (tie-in) to the existing gas pipelines completed by construction of gas pipelines and gasified facilities during their commissioning;

- commissioning works;

- maintenance;

- repairs (current and major);

- reconstruction of underground gas pipelines;

- emergency maintenance;

- emergency recovery works;

- switching on and off of gas-using equipment operating seasonally;

- disconnection and dismantling of inactive gas pipelines and gas-using equipment;

- technical diagnostics;

- maintenance of operational technical documentation.

Technical operation of gas filling stations and points, warehouses of household cylinders, gas filling stations is carried out in accordance with the requirements of PB 12609, OST 15339.3-052-2003 and other regulatory documents approved in accordance with the established procedure.

The operating organization should have equipment, instrumentation, motor vehicles and mechanisms, technological equipment, tools and materials sufficient to carry out technical operation work in the scope provided for by regulatory documents approved in accordance with the established procedure.

Quality check of applied materials, insulation and welding works, etc. is performed by laboratory or other specialized departments of operational organization.

The scope of maintenance works, terms, methods and methods of their execution shall comply with the requirements of PB 12529, PB 12609 and OST 15339,30512003.

Organization of gas hazardous and fire works is carried out in accordance with the procedure established by PB 12529.

Production instructions are developed in accordance with the requirements of PB 12259, PB 12609, OST 15339,30512003, documentation of equipment manufacturers, standard instructions and provisions approved in accordance with the established procedure.

Production control in the operational organization is carried out on the basis of the provision developed in accordance with the requirements of PB 12529, taking into account the profile of the work performed.

It is recommended to upgrade the skills of specialists of production departments (services) at least once every 5 years at specialized training courses (in training centers, mills, etc.).

Composition of operational documentation.

Certificates of acceptance of facilities for operation and the accompanying as-built documentation for design and construction should be stored in the archive of the operational organization for the entire life of the facilities. The operational organization compiles and maintains operational documentation on the types of works performed during technical operation, performance indicators, verification of measuring instruments.

It is permitted to maintain operational documentation on PC and store it on magnetic media.

Types and forms of operational documentation shall be established by effective regulatory and technical documents.

The scope of the produced operational documentation shall comply with the specified in the regulatory and technical documents, and in the absence of such instructions shall be determined by the operational organization.

The main forms of operational documentation are given in OST 15339.3-053-2003.

In case of loss of as-built documentation, restoration of information about the object is performed by visual inspection and measurements, based on readings of devices, results of technical examination, pit inspections, control testing and other methods.

During further operation of the facility, the restored documentation is updated and supplemented on the basis of the information revealed during the maintenance and repair work.

During technical operation of external gas pipelines the following types of works are performed:

- commissioning of gas pipelines completed by construction (gas start-up);

- control of pressure and degree of odorisation of gas supplied through gas distribution networks in settlements;

- maintenance, maintenance and overhaul of gas pipelines and structures on them, including fittings installed at the entrance to the building or in front of the external gas-using equipment of the consumer;

- maintenance and repair of gas pipeline protection against electrochemical corrosion, check of EHZ efficiency;

- checking the presence and removal of moisture and condensate from gas pipelines;

- technical diagnostics of gas pipelines;

- localization and elimination of accidents, emergency recovery works;

- dismantling of gas pipelines and structures on them.

Sequence and methods of works execution are given in OST 15339.3-051-2003, existing industry standard instructions, guidelines, procedures, process charts approved in accordance with the established procedure, and should be reflected in production instructions developed by operating organizations.

Commissioning of steel and polyethylene gas pipelines completed by construction is carried out by connecting them to the existing gas pipelines of the gas distribution network with simultaneous gas start-up.

The procedure for execution of works during commissioning of gas pipelines is given in this section.

For tie-ins of completed gas pipelines, technologies should be applied that correspond to the design method of their connection to the existing gas distribution networks.

Control of gas pressure in gas distribution networks of cities and settlements is carried out using its periodic (but at least once a year) measurements. For the procedure of gas pressure measurements, refer to this section.

Control over the degree of gas odorization is carried out by checking in accordance with the state standards of gas odor intensity from samples taken at the control points and with the periodicity established by the GRO.

Checking of moisture and condensate in gas pipelines, their removal is carried out with a periodicity that excludes the possibility of blockages.

The following types of works are performed during maintenance of gas pipelines:

- supervision of the state of gas pipelines by bypassing routes;

- technical survey of gas pipelines.

Gas pipeline routes shall be bypassed within the timeframe established by the operating organization, but not less often than stipulated by PB 12529. Bypass schedules should be reviewed periodically, at least once every 3 years, based on changes in the operating conditions of gas pipelines. Works during bypass of gas pipelines routes are performed in accordance with the requirements of PB 12529 and this section.

Periodic technical inspection of gas pipelines is carried out within the deadlines set by PB 12529 to detect gas leaks, as well as damage to insulation coatings of underground steel gas pipelines.

Extraordinary instrument technical inspections of gas pipelines are carried out in cases stipulated by PB 12529.

Maintenance of valves installed on gas pipelines is performed in accordance with the requirements of section 8 of OST 15339,30,51-2003

Current and major repairs (replacement, reconstruction of gas pipelines) are carried out based on the results of maintenance and diagnostics of gas pipelines.

The main types of work related to the current and overhaul of gas pipelines, methods of localization and elimination of accidents are established by PB 12529.

Reconstruction of steel gas pipelines, which are not subject to further operation, is carried out by drawing polyethylene pipes inside worn out steel gas pipelines, lining the inner surface of steel gas pipelines with a synthetic fabric hose based on a special two-component glue, by other methods allowed for use in accordance with the established procedure.

Technical diagnostics of gas pipelines are carried out in accordance with the requirements of PB 12529 according to the methods approved by the Gosgortekhnadzor of Russia.

Emergency dispatch maintenance of gas pipelines is carried out in accordance with the requirements of PB 12529 and OST 15339,30512003.

Emergency recovery works are carried out if it is necessary to repair the gas pipeline and restore gas supply to consumers after temporary elimination of gas leakage.

3.2 Operation of protective installations

Maintenance and repair of means of electrochemical protection of underground gas pipelines against corrosion, control over the effectiveness of EHZ and development of measures to prevent corrosion damage of gas pipelines are carried out by personnel of specialized structural divisions of operational organizations or specialized organizations.

Maintenance and repair of insulating flanges and EHZ units is carried out according to schedules approved in accordance with the established procedure by the technical management of the organizations - owners of electrical protection units. During operation of EHZ facilities, their failures in operation and idle time are recorded.

Maintenance of EHZ cathodic plants includes:

- check of condition of protective grounding circuit (re-grounding of zero wire) and supply lines. External inspection checks the reliability of visible contact of the ground conductor with the housing of the electrical protection plant, the absence of a break in the supply wires on the overhead line support and the reliability of contact of the zero wire with the housing of the electrical protection plant;

- inspection of condition of all components of cathodic protection equipment in order to establish serviceability of fuses, reliability of contacts, absence of traces of overheating and heating;

- cleaning of equipment and contact devices from dust, dirt, snow, check of presence and conformity of marking marks, condition of carpets and wells of contact devices;

- measurement of voltage, current value at the converter output, potential on the protected gas pipeline at the connection point with the electrochemical protection unit turned on and off. If the parameters of the electrical protection plant do not correspond to the commissioning data, its operating mode shall be adjusted;

- entry of relevant entries in the operating log.

Maintenance of tread units includes:

measuring the tread potential relative to the ground when the tread is disconnected;

- measurement of the potential of the "gas pipeline" with the tread on and off;

- value of current in the circuit "tread - protected structure."

Maintenance of insulating flange connections includes work on cleaning flanges from dust and dirt, measuring the potential difference of the "gas pipeline" before and after the flange, voltage drop on the flange. In the area of ​ ​ influence of wandering currents, the measurement of the potential difference of the "gas pipeline" before and after the flange should be carried out synchronously.

The state of adjustable and unregulated jumpers is checked by measuring the potential difference of the "structure" at the points of connection of the jumper (or at the nearest measuring points on underground structures), as well as measuring the value and direction of current (on adjustable and detachable jumpers).

When checking the efficiency of electrochemical protection plants, in addition to the works performed during technical inspection, potentials are measured on the protected gas pipeline at support points (at the boundaries of the protection zone) and at points located along the gas pipeline route, every 200 m in settlements and every 500 m on straight sections of inter-village gas pipelines.

EHZ maintenance includes:

- all types of technical inspection works with performance check;

- measurement of insulation resistance of current-carrying parts;

- repair of rectifier and other circuit elements;

- elimination of drain line breaks. During the current repair of the EHZ equipment, it is recommended to conduct a full audit of it in workshop conditions. During the inspection of the EHZ equipment, it is necessary to ensure the protection of the gas pipeline by installing equipment from the swing fund.

Overhaul of EHZ plants includes work related to the replacement of anode earthing, drain and supply lines.

After overhaul, the main electrochemical protection equipment is checked in operation under load during the time specified by the manufacturer, but not less than 24 hours.

Зубаирова. План трассы.cdw

Зубаирова. Защита катодная.cdw