The layout of the pipeline is what we often say.

The general requirements for pipeline layout design are:

1) The pipeline layout design shall meet the requirements of process pipeline and instrument flow chart;

2) Pipeline layout should be planned in a unified way, so as to be safe, reliable, economical and reasonable, meet the requirements of construction, operation and maintenance, and strive to be neat and beautiful;

3) When determining the pipeline direction and laying mode in and out of the device (unit), internal and external coordination should be achieved;

4) The pipeline laying in the factory area shall be consistent with the devices (units), roads and buildings in the factory area. Structural coordination, etc. Avoid pipelines around the device (unit) to reduce the intersection of pipelines with railways and highways;

5) The pipeline should be turned overhead or underground; If necessary, it can be buried or laid in a pipe trench;

6) Pipes shall be arranged in rows. Ground pipelines shall be laid on pipe supports or piers;

7) When arranging pipelines on the pipe supports and piers, the vertical load and horizontal load on the pipe supports or piers should be balanced;

8) There should be a margin of 1o%-3o% on the pipe supports or piers of the whole plant (including crossing culverts), and its load should be considered. The pipe rack of the main pipe gallery of the device shall have a margin of 10%-20%, and its load shall be considered;

9) Layout of pipelines and large-diameter pipelines with special requirements for distance, angle and elevation difference. Used for conveying media should meet the requirements of equipment layout design;

10) The pipeline layout shall not hinder the installation and maintenance of equipment, pumps and their internal components and the passage of fire-fighting vehicles;

1 1) The pipeline layout shall make the pipeline system have the necessary flexibility. Under the condition of ensuring the flexibility of the pipeline and the inertia of the force and moment of the pipeline to the nozzle of the equipment and pump not exceeding the allowable value, the pipeline should be the shortest and the parts should be the least;

12) The setting of supporting points should be considered at the same time of pipeline planning. The natural shape of pipeline should be used to realize self-compensation;

13) The pipeline layout should be "step by step" or "step by step" to reduce air bags or liquid bags. When unavoidable, venting and emptying shall be set according to the operation and maintenance requirements. Pipeline layout should reduce "cecum";

14) When the pipeline of gas-liquid two-phase flow is divided into two or more paths from one path, the pipeline layout should consider symmetry or meet the requirements of pipeline and instrument flow chart.

(2) Pipes and valves. Instruments, equipment, etc. Connections shall be made by welding, except flanges or threads.

Flanges, threads or other detachable connections shall be considered for the following idling conditions:

L) Where disassembly is required for maintenance, cleaning and purging;

2) Lined pipe or jacketed pipe;

3) The pipeline is composed of two sections of dissimilar materials and should not be connected by welding;

4) Pipeline connection points with difficulty in on-site heat treatment of welds;

5) galvanized pipe with nominal diameter less than or equal to 100mm;

6) Set the position of blind plate or "8" blind plate.

(3) The gas branch pipe shall be connected from the top of the main pipe.

(4) The toxic medium pipeline shall be connected by welding, and flange or threaded connection shall not be adopted unless there is special need. Toxic medium pipelines shall be clearly marked to distinguish them from other pipelines, and toxic medium pipelines shall not be buried or removed.

(5) When arranging solid materials or pipelines containing solid materials, the pipelines should be as short as possible. Less turns and no dead ends:

L) The connection between the branch pipe of solid materials and the main pipe shall be diagonally connected along the medium flow direction, and the included angle shall not be greater than 45;

2) The bending radius of the elbow on the solid material pipeline should not be less than 6 times of the nominal diameter of the pipeline;

3) Slurry pipelines and high-viscosity liquid pipelines containing a large amount of solid materials should have slopes.

(6) The pipeline that needs thermal compensation shall be analyzed from beginning to end to determine a reasonable thermal compensation scheme.

(7) For pipes with slopes on the pipe gallery, the height of pipe supports can be adjusted. It is realized by adding section steel or steel plate pillow on the pipe rack. The vent header (or flare header) should be arranged at the top of the pipe gallery column to facilitate elevation adjustment.

(8) When arranging pipelines connected with rotating machinery and equipment, the pipeline system should be flexible enough to meet the allowable stress requirements of the equipment nozzle. When necessary, the following measures can be taken:

L) Change the pipeline direction and enhance the natural compensation ability;

2) Select the spring hanger;

3) metal bellows compensator is selected;

4) Set a limit bracket at an appropriate position.

(9) When arranging the pipeline connected to the reciprocating compressor, the natural frequency of mechanical vibration of the pipeline system and the natural frequency of the pipeline gas column should avoid the excitation frequency of the machine. When necessary, the following measures can be taken:

1) plus anti-vibration support;

2) Appropriately enlarge the pipe diameter;

3) add pulse attenuator or orifice plate;

4) Set the buffer reasonably, avoid the length of vibrating tube, and reduce elbows as much as possible.

(10) The branch pipe should not be set at the part with large bending moment on the vibrating pipeline.

(1 1) Elbows with bending radius not less than 1.5 times the nominal diameter shall be used for pipelines prone to vibration (such as outlet pipelines of reciprocating compressors and reciprocating pumps). The branch pipe is externally connected along the medium flow direction.

(12) When connecting a branch pipe with a nominal diameter less than or equal to 40mm from a pipeline where vibration may occur, the joint should be strengthened regardless of whether there is a valve on the branch pipe.

(13) The self-flowing horizontal pipeline should have a slope of not less than 3‰ along the flow direction of the medium.

(14) When the pipeline passes through the floor, roof or wall of a building, a casing shall be added, and the gap between the casing and the pipeline door shall be sealed. The diameter of the casing should be greater than the outer diameter of the pipeline insulation layer. And shall not affect the thermal displacement of the pipeline. The weld on the pipeline should not be in the casing, the distance from the end of the casing should not be less than 150 mm, and the casing should be 50 mm higher than the floor and roof. Rain cover should be set when the pipeline passes through the roof. Pipes should not pass through firewalls or explosion-proof walls.

(15) When arranging corrosive media, toxic media and high-pressure pipelines, the hazards to personnel and equipment caused by leakage of flanges, threads and packing seals should be avoided. Above the pedestrian passage or machine pump, the parts that are easy to leak should be avoided, otherwise safety protection should be set up.

(16) For thermal insulation pipes, pipe supports shall be provided at pipe piers and pipe supports. If there is no requirement for pipes without insulation layer, there is no need to set up pipe supports. When the insulation layer thickness is less than or equal to 80mm, the pipe rack with the height of 100mm is selected; When the insulation layer thickness is greater than 80mm, the pipe rack with the height of 150mm shall be selected; When the insulation layer thickness is greater than 130mm, the pipe rack with a height of 200mm should be selected; Cold-insulation pipe bracket shall be selected for cold-insulation pipe.

(l7) When the terrain elevation difference of the plant area is large, the pipeline laying of the whole plant should be consistent with the terrain elevation difference. Adjust the pipe gallery elevation at an appropriate position. The minimum slope of the pipeline shall be 2‰. The slope change point of the pipeline should be located near the bend or fixed point.

(18) For pipelines crossing the railways and roads in the factory area, pipeline components such as valves, metal bellows compensators, flanges and threaded joints should not be installed on the crossing section or the crossing section.

(19) For buried pipelines with thermal displacement, piers can be set when the radian of the pipeline allows, otherwise thermal compensation measures should be taken.

(20) When arranging pipelines, the setting of pipeline welds shall meet the following requirements:

1) The distance between the center of the butt joint of the pipeline and the bending point of the elbow should not be less than the outside diameter of the pipeline; And not less than100 mm;

2) Center spacing between two adjacent butt welds on the pipeline:

A pipes with a nominal diameter less than 150mm shall not be less than the outside diameter and not less than 50 mm;

B. The pipeline with nominal diameter equal to or greater than 150m shall not be less than150mm; ;

3) The clear distance between girth weld and the edge of support and hanger shall not be less than 50mm；; The minimum clear distance between the weld requiring heat treatment and the edge of the bracket and hanger should be more than 5 times the width of the weld and not less than100 mm. ..