Cogeneration Plant Gas Supply Project

General Data

Compliance of working documentation with applicable norms and rules.

The technical solutions adopted in the project comply with the requirements of industrial safety of hazardous production facilities in the field of protection of the population and territories from emergency situations, environmental protection, environmental, fire safety, as well as the requirements of State standards in force on the territory of the Russian Federation.

The project is executed according to Construction Norms and Regulations 42012002 "Gas-distributing systems", the joint venture 42101 "General provisions on design and construction of gas-distributing systems from steel and polyethylene pipes", the joint venture 42102 "Design and construction of gas pipelines from metal pipes" Safety rules of systems of gas distribution and gas consumption of PB 1252903 and fulfills the requirements of Federal law No. 116 of 21.07.97 "About industrial safety of hazardous production facilities".

Equipment (technical devices) and materials (including foreign production) envisaged by the project are certified for compliance with safety requirements and have Rostekhnadzor permission for use.

Justification of changes made

The external gas pipeline of the gas piston unit CAT G 3516 LLC "Trading House Vishnevogorsky GOK" was installed according to the project 018.08.2G2 GSN developed by the project organization TekhPromProekt LLC and has an industrial safety conclusion Reg No. 56-PD-02131-2009

During commissioning at the CAT G 3516 gas piston unit, the following deficiencies in the operation of the gas consuming system were revealed:

- at the moment of unit start-up the gas pressure downstream GRPP decreases to zero, and then increases to 0.15 MPa, which is unacceptable and leads to actuation of safety shut-off valve (there is no possibility of smooth regulation);

- during operation, the unit does not develop power over 80%, as there is a decrease in the gas pressure in the system (there is not enough throughput of the GRPP)

- at the moment when the gas piston unit stops, the gas pressure increases sharply, which also leads to the actuation of the safety valve.

Based on the above, the organizations performing the commissioning of the gas piston unit and the gas-using system, it was decided to replace GRPSH03M (2) U1 with SHGRP based on the pressure regulator RS 250.

This change to the project 018.08.2G2GSN provides for the manufacture and installation of SGRP.

Selection of SGRP equipment

Selection of pressure regulator:

The regulator capacity shall be 1520% more than the maximum design gas flow rate.

,

where: Qmax - Maximum gas flow per gas piston unit is 294 m3/h.

m3/hour

Capacity of gas pressure control device RS 250, at inlet pressure of 0.3 MPa and outlet pressure of 20 kPa is 350 m3/h

Filter selection:

The capacity of the filter is determined based on the maximum pressure drop on its cassette, which should not exceed 500 dPa for the strainer.

The throughput of the FG 50C filter at a pressure of 0.1 MPa is 450 m3/h, and the pressure drop on the cassette is 500 Pa.

Selection of safety relief valve:

The amount of gas to be discharged through the UCS within an hour, in the presence of BSV before the regulator, is determined by the formula:

where: Qd - design capacity of the pressure regulator m3/h

0, 0005· 350 = 0,175 m3/hour

Gas flow rate through safety relief valve KPS-S when pressure exceeds by 12 kPa is 0.5 m3/h

The bypass device in the SGRP is not required, since the CAT G 3516 gas piston unit is designed to work only in automatic mode and allows interruptions in gas consumption.

Cabinet gas control station (SGRP)

The SGRP includes the following equipment:

- ball flange valve KSH 16/50 dy 50;

- gas filter FG 50C dy 50;

- gas pressure control device RS 250 dy 50 with built-in safety valve SAV;

- pulse gas pipelines dy 10;

- KiPiA devices;

- KPS-S dy 20 safety relief valve,

- blowdown and discharge pipelines dy 20;

- ball cranes 11B 27p dy 20 and 15;

- three-way cranes 11b18bk dy 15

WGRP Settings:

Gas pressure at the inlet to ShGRP R = 0.3 MPa

Gas pressure at HSGRP outlet R = 0.02 MPa

Limits of safety shut-off valve actuation,

at increase in pressure P = 0.0250 MPas

at pressure decline P = 0.0150 MPas

Limit of safety relief valve actuation

at increase in pressure P = 0.0230 MPas

Maximum gas flow is Q = 350 m3/h

Installation and Testing and Operation Instructions

Equipment (technical devices) and materials (including those of foreign production) envisaged by the project are certified for compliance with safety requirements and have permission from Gosgortekhnadzor for use.

Isolation valves used in the gas supply system comply with SP 4210497 "Code of Rules for the Use of Isolation Valves for the Construction of Gas Supply Systems" and Chapter 7 of SP 42101 "General Provisions for the Design and Construction of Gas Distribution Systems from Steel and Polyethylene Pipes"; is intended for transportation of natural gas during the entire service life established by the manufacturer and has the corresponding record in the certificate.

According to GOST 954493, it is allowed to install valves with class "B" tightness on gas pipelines with a diameter of up to 80 mm.

Pipes used in the construction of gas supply systems shall have a record in the certificate of assurance that the pipes will withstand hydraulic pressure, the value of which meets the requirements of the standards or technical specifications for pipes.

Connection of pipes and shaped parts of steel gas pipeline shall be performed by manual electric arc and gas welding with continuous normal gas-tight seam. The type and design of weld parameters shall be in accordance with the main pipe material and meet the requirements of GOST 1603780 * "Welded Steel Piping Connections." Electrodes for welding of the E42A, E46A, E50A type in accordance with GOST 946775*. *. Welding wire of SV08AA, SV-08HA, SV08G2S, SV-08GS, SV12GS grades as per GOST 224670. Impact toughness of metal of pipes and welds shall be not less than 30 J/cm2 (3 kg s/cm2) at design ambient temperature in the area of Snezhinsk.

The transverse joints shall be not less than 50 mm from the edge of the attachments. On gas pipelines of FRG (ShGRP) at tie-ins of branches up to 50 mm inclusive (including pulse lines) the distance from joints of welded connectors to ring joints of the main gas pipeline shall be at least 50 mm.

Seal the flange connections of the gas pipeline with paronite gaskets. Seal the threaded connections of the gas pipeline with a "FUM" tape or linen strand impregnated with surik or belils on natural olive.

Install lock nuts on all threaded connections, and turn limiters and plugs on the valves.

The accuracy class of the pressure gauges shall not be less than 1.5. In front of the pressure gauges, a three-way crane or similar device is provided for checking and disconnecting the pressure gauge.

Butt joints of above-ground steel gas pipelines of all pressures with diameter less than 50 mm are not subject to physical control -

Butt joints of gas pipelines with a diameter of more than 50 mm in GRP and GRU are subject to physical control in the amount of 100%.

Gas pipeline leak tests should be carried out in accordance with the requirements of SNiP 42012002 "Gas Distribution Systems" and PB 1252903 "Safety Rules for Gas Distribution and Gas Consumption Systems":

- gas pipelines and GRP equipment with pressure above 0,005 to 0.3 MPa shall be tested with pressure 0.45 MPa within 12 hours;

After tightness tests, paint the ShGRP gas pipeline in yellow with two layers of paint, varnish or enamel intended for external work at the calculated ambient temperature with warning red rings as per GOST 1420269.

The SGRP equipment shall be installed in a metal cabinet. Ventilation holes are made in upper and lower parts of cabinet for ventilation of internal cavity. Lock the cabinet with the key from which the person in charge (shift supervisor) must be located. Paint the cabinet in yellow, and the warning inscription "Flammable - gas" in red.

It is allowed to use pipes, shutoff valves, welded and insulating materials not provided by this project, but allowed for use by the current GOST and Rules.

When the gas supply system is put into operation, commissioning works shall be carried out to adjust the system for the operating parameters specified in the design.