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Pipeline Classification In petrochemical plants, pipelines with different operating parameters and properties of conveying media vary greatly, and their importance and risk are also different. In order to better ensure the reliability and safety of pipelines during operation, different design, manufacturing and construction requirements are put forward for pipelines with different degrees of importance. So grading the pipeline is necessary. Determination of pipeline design conditions 1 Design pressure The design pressure of petrochemical pipelines and their components should not be lower than the pressure under the most severe conditions combined with internal pressure and temperature during operation. 1. The design pressure of all pipelines connected to equipment or pressure vessels should be no less than the design pressure of the equipment or container, and meet the following requirements: (1) For pipelines equipped with safety pressure relief devices, the design pressure should not be lower than the sum of the safety relief pressure and the static pressure of the liquid column. (2) When there is no safety pressure relief device, the design pressure should not be lower than the sum of the highest possible pressure of the pressure source and the hydrostatic column pressure. 2. The design pressure of the outlet pipeline of a centrifugal pump without a safety pressure relief device should be the larger of the following two values: (1) The normal suction pressure of the centrifugal pump plus 1.2 times the rated pressure difference issued by the pump. (2) The maximum suction pressure of the centrifugal pump plus the outlet pressure difference of the pump 3. The vacuum pipeline pressure is 0.098MPa. 2 Design temperature The design temperature of chemical pipelines and their components should not be lower than the most demanding conditions consisting of pressure and temperature during operation. The design temperatures of different pipelines are determined by the following requirements: 1. Design temperature of pipelines without insulation (1) For SHA-level pipeline components, the medium temperature should be used as the design temperature. If other temperatures are used as the design temperature, it must be calculated and verified through experiments. (2) For the design temperatures of other levels of pipelines and their components, when the medium temperature is less than 65 degrees, the medium temperature is taken. When the medium temperature is greater than or equal to 65 degrees, the design temperature is selected according to the following principles.: A. The design temperature of pipes, butt welding fittings, socket welding or butt welding valves and other components with a wall thickness similar to that of the pipeline is not generally higher than 95% of the medium temperature. B. Flanges, gaskets and valve fittings with flanges should not be lower than 90% of the medium temperature. C. Fasteners such as bolts and nuts should not be lower than 80% of the medium temperature. 2. Pipes with external insulation layers should take the maximum and minimum operating temperature of the medium as the design temperature based on the severity of the effects of temperature conditions on the pipe. 3. For pipes with inner or inner insulation layers, the design temperature of the base material should be determined by heat generation calculation or actual measurement. 4. When the process temperature of a jacketed pipe with heat tracing is higher than the heating medium, the temperature of the process medium is taken as the design temperature. ； When the temperature of the process medium is lower than the temperature of the heating medium, the temperature of the heating medium minus 10 degrees or the temperature of the process medium is higher 5. For safety pressure relief pipelines, the highest or lowest temperature that may occur during discharge should be used as the design temperature. 6. The pipelines required to be purged should be determined according to specific conditions. Factors that should be considered in pipeline layout 1. Material factors Pipelines with corrosive materials should be arranged below or outside parallel pipelines. Pipes carrying flammable, explosive, toxic and corrosive materials should not be laid in living areas, stairs and corridors, and should be equipped with safety valves, anti-riot membranes, flame arresters, water seals, etc. Waterproofing, anti-riot devices, and vent pipes should be led to designated outdoor places or more than 2m above the roof. The hot and cold pipes should be arranged as separate as possible. As a last resort, the hot pipe is on top and the cold pipe is on the bottom. The distance between the outer surfaces of the insulation layer is generally not less than 0.5m when running up and down. When arranged in a cross arrangement, it should not be less than 0.25m. The thickness of the insulation material and insulation layer shall be in accordance with the regulations. Pipe laying should have a slope. The slope direction is generally along the direction of material flow, but there are also slopes opposite to the direction of material flow. The slope is generally 1/100~5/1000. Pipes transporting materials with high viscosity require a larger slope, which can be as high as 1/100. The slope of the material pipeline containing solid crystals can be about 5/100. For buried pipelines and pipelines laid in trenches, when production is stopped, the accumulated materials are not considered to be exhausted, and the laying slope does not need to be considered. The slopes of the relevant material pipelines are listed in the table. In addition to meeting normal production requirements, the pipeline layout should also meet the requirements for start-up, shutdown and accident handling. During start-up and shutdown, since the relevant parts are started and stopped, bypass pipelines should be set up. Pipelines should also be set up for start-up loading, discharge during shutdown and reprocessing of unqualified products. The pipelines should be able to adapt to changes in operations to avoid tediousness and waste. Drain ports and expanders with traps should be installed at appropriate locations in the steam main pipe and long-distance pipelines. For safety reasons, try not to introduce high-pressure steam directly into the low-pressure steam system. If necessary, a pressure reducing valve should be installed and a safety valve should be installed on the low pressure system. Sewage should be discharged to a special system and comprehensive utilization should be considered. Depending on the specific conditions of the sewage, the combined flow type (that is, industrial sewage, rainwater and toilet water are all discharged from one pipe network) or the split flow type (that is, industrial sewage and toilet water are discharged from one pipe network, and rainwater and industrial clean water are discharged from another pipe network). Toxic sewage must be treated before being discharged. The vacuum pipeline should be shortened as much as possible to avoid excessive twists and turns, so that the resistance is small and a greater vacuum degree can be achieved. You should also avoid using stop valves because their resistance is large and affects the vacuum of the system. 2 Construction, operation and maintenance pipelines with many branch pipes should be arranged outside the parallel pipes. When branching the pipe, the gas pipe is led from the top and the liquid pipe is led from the bottom. Pipelines should be arranged centrally and overhead, try to run in straight lines with as few turns as possible, and do not block doors and windows or hinder the maintenance of equipment, valves, pipe fittings, etc. ； Should not hinder crane operations ； Pipes should not be installed in the 2.2m space on the walking aisle floor. Ducts should avoid "air pockets," "pockets," and "cecums." The arrangement of the gas gathering system should be such that steam can be easily discharged to the highest point. If possible, the pipes should be installed along the wall, and the distance between the pipes and the wall should be able to accommodate pipe fittings, valves and facilitate maintenance. 3. Safety production valves should be arranged in locations that are easy to operate. Frequently operated valves should be arranged in order of operation. Valves that are easy to open incorrectly and can cause major accidents should be spaced apart from each other and painted in different colors. When underground pipelines pass through roads or loaded areas, protective measures should be taken. The weight of pipes and valves should not be considered to be supported on equipment (especially manufacturing equipment, non-metallic equipment, ferrosilicon pumps, etc.). 4. Other factors Between two equipments that are close to each other, the pipelines should generally not be directly connected. Because the gaskets are not suitable for registration, it is difficult to connect them tightly. Exceptions are made if one of the devices is not fixed to the building or has corrugated expansion and contraction. It is recommended to use 45. Miter or 90. Bend connection. When the pipeline passes through the floor, roof or wall, a pipe sleeve with a large diameter should be installed. The pipe sleeve should be 50mm higher than the floor and platform surface. The pipeline layout should take into account other pipelines such as cables, lighting, instruments, heaters, etc. They should be fully considered and placed in their proper places. Piping layout of unit equipment 1. Piping layout of pumps. There are three ways to lay out pumps.: Open-air layout, semi-open-air layout and indoor layout: Open air layout: Pumps arranged in the open air are usually concentrated on the lower side of the pipe gallery, or they can also be dispersed near the pumped equipment. Its advantages are good ventilation and convenient operation and maintenance. ； Semi-open air layout: Pumps arranged in a semi-open air are suitable for rainy areas. Generally, the pumps are arranged below the pipe gallery and a canopy is installed on the upper part of the pipe above. Or the pump can be arranged on the lower ground of the frame, and the frame platform can be used as a canopy. These pumps can be arranged in single row, double row or multiple rows according to the design and layout requirements related to the pump. ； interior layout: In cold or windy and sandy areas, the pump can be placed indoors. If the process requires the equipment to be arranged indoors, the pump to which it belongs should also be arranged indoors. Pump pipeline design and pump layout specific requirements are as follows:: l) Pumps arranged in rows should be arranged in groups according to fire protection requirements, operating conditions and material characteristics. ； When the pump is arranged in open air or semi-open air ； Flammable liquid pumps with operating temperatures equal to or higher than the auto-ignition point should be arranged centrally ； There should be a fire separation distance of not less than 4.5m between the pump and the flammable liquid pump whose operating temperature is lower than the auto-ignition point. ； There should be a fire separation distance of not less than 7.5m between the pump and the liquid hydrocarbon pump. ； 2) When the pumps are arranged in rows, the pump end should be taken out. Align the population center line, or align the pump end foundation edge ； 3) When the pumps are arranged in double rows, the power ends of the two rows of pumps should be opposite to each other, and a maintenance channel should be left in the middle. ； 4) When the pump is arranged below or outside the main gallery, the minimum clear width of the pump area channel is 2m and the minimum clear height is 3m. The width of the operating channel in front of the pump end should not be less than 1m. ； 5) When the pump is arranged below or outside the pipe gallery, whether it is a single row or a double row, the center line of the pump and driver should be perpendicular to the direction of the pipe gallery. ； 6) When the pump is arranged indoors, the clear distance between the two rows of pumps should not be less than 2m. The clear distance between the pump end or pump side and the wall should meet the operation and maintenance requirements and should not be less than lm ； 7) Except for small pumps installed on a joint foundation, the clear distance between two pumps should not be less than 0.7m ； 8) The foundation surface of the pump should be 200mm higher than the ground. Minimum shall not be less than 100mm ； When installing a filter in front of the pump suction inlet, the height of the pump foundation should be considered so that the filter can be easily cleaned and disassembled. ； 9) When the vertical pump is arranged under the main gallery or under the frame, space required for pump installation and maintenance should be left above it. ； 10) The pump room that transports extremely hazardous substances (such as propylene hydrocyanic acid, etc.) should be separated from other pump rooms. ； 11) The fire pump room should be equipped with dual power sources ； 12) Public standby pumps should be arranged in the middle of the corresponding pumps ； 13) The layout of the pump should take into account the pipeline flexibility design requirements. ①The pump body should not bear the weight of the inlet and outlet pipes and valves, so the pipes before and after the pump must be equipped with support devices, so that there are no temporary supports when the pump is removed as much as possible. ②. The suction pipe should be as short as possible, with as few turns as possible, and avoid sudden reduction in pipe diameter. ③, The diameter of the suction pipe should not be smaller than the suction inlet of the pump. When the suction inlet of the pump is in the horizontal direction, an eccentric reducer should be configured. If the suction inlet of the pump is vertical, a concentric reducer can be configured. ④. In order to prevent the material from backwashing when the pump is stopped, a check valve should be installed on the discharge pipe of the pump. The check valve should be installed before the cut-off valve, and the cut-off valve should be closed after the vehicle is stopped to prevent the check valve plate from being damaged by long-term pressure. 2 Pipe layout of the heat exchanger (1) The process pipe layout of the shell and tube heat exchanger should pay attention to the flow direction of hot and cold flows. Generally, the heated medium (cold flow) should be from bottom to top, and the condensed or cooled medium (hot flow) should be from top to bottom. The clearance between the pipe and the ground or platform is greater than or equal to 100mm. (2) Piping should not hinder equipment maintenance ； Does not affect the core pulling of the equipment (tube bundle or inner tube) ； Do not hinder the removal or installation of the equipment's flange and the valve's own flange. (3) The pipes of the parallel heat exchanger should be arranged symmetrically to ensure uniform flow distribution. (4) The downcomer and riser pipes of the reboiler should be as short and straight as possible within the allowable stress range of thermal expansion, and reduce the number of elbows to reduce pressure drop. When laying out the plan, the tube box of the heat exchanger faces the road, making it easy to extract the tube box, and the top cover faces the pipe gallery. Before piping, determine the installation and maintenance space at both ends of the heat exchanger and around the flange (the wrench space in the picture, the space to open the head, etc.). There should be no obstacles in this space. When piping, the pipes should be as short as possible and easy to operate and maintain. The pipes with turns on the pipe gallery are arranged on the right side of the heat exchanger, and the pipes leading from the bottom of the heat exchanger also turn upward from the right side. Utility pipes leading from the main pipe of the pipe gallery can be routed on either side of the heat exchanger. Align the cooling water inlets on the pipe box and arrange them above the cooling water underground main pipe, and arrange the return pipe beside the cooling water main pipe. The heat exchanger can be directly connected overhead with pipes to adjacent equipment. The connecting pipes above and below the pipe box should be turned as early as possible and a short elbow should be provided to facilitate the disassembly of the pipe box. Valves, automatic regulating valves and instruments should be arranged along the operating channel and close to the heat exchanger, so that people can operate while standing on the channel. The elevations of the pipes connected to the pipe gallery, the outlet pipes of the pumps under the pipe gallery, the equipment with a lower height than the pipe gallery and the pipes of the heat exchangers should all be 0.5-0.8m lower than the pipe gallery. If one layer cannot be arranged, it can be placed on the next layer, with a distance of 0.5 - 0.8m between the two layers. Steam branch pipes should be led from above the main pipe to prevent condensation from entering. The heat exchanger should have a suitable bracket so that the weight of the pipe cannot be pressed on the interface of the heat exchanger. Instruments should be arranged in a place convenient for observation and maintenance. 3 Tower pipe layout Tower pipes can generally be divided into tower top pipes, tower side pipes and tower bottom pipes. The tower top pipeline includes tower top oil and gas, safety valve inlet and outlet, oil and gas venting and other pipelines ； The side pipes of the tower include reflux, feed, side extraction, stripping steam, reboiler inlet and return pipes ； The tower bottom pipeline includes tower bottom extraction and liquid drainage pipelines. The above-mentioned pipes are all connected to the openings on the tower body, and are generally laid along the tower body. Usually, the surrounding area of the tower is roughly divided into the operating side (maintenance side) required for operation and maintenance and the pipe side required for piping. The pipelines should be arranged on the pipeline side and should not be evenly distributed around the pipeline. There is generally no platform on the pipeline side, and the platform and manhole should be located on the operation side. The pipeline layout should be planned from the top of the tower to the bottom of the tower, and the location of the tower top and large-diameter pipes and the direction of the gravity pipes should first be considered, then the pressure pipes and general pipes should be arranged, and finally the bottom of the tower and small-diameter pipes should be considered. The larger diameter pipes in the upper part of the tower should be arranged in the middle of the pipe side, and the pipes connected to the middle and lower parts should be arranged sequentially on both sides. The "tube bundles" arranged on the side of the pipeline should be arranged at the same radius of curvature from the center of the equipment as much as possible. The pipes can also be arranged parallel to the tangent line of the equipment. Generally, the clear distance between the outer wall of the pipe and the outer wall of the tower is at least 300mm (when the pipe or tower is equipped with an insulation layer, it is calculated based on the outer wall of the insulation layer). 1. Arrangement method: Principle - similar equipment is arranged in a centralized manner. distance between towers: The foundation below the ground cannot be bumped, not less than 2.5m. 1) Single row layout: When there are multiple towers on one side of the pipe gallery, if their diameters are not much different, the center lines should be aligned ； If the diameter difference is large, align the tangents close to the side of the pipe gallery. Generally, it is 3m away from the pipe gallery. If there is a tower bottom pump, the distance should be considered for the operation and maintenance of the pump. 2) Non-single row layout: For towers with smaller diameters and taller bodies, they can be arranged in double rows or in a triangle. In this way, a joint platform can be used to connect the towers together, thereby increasing relative stability. However, when making a joint platform, the thermal expansion problem at different operating temperatures of the equipment must be considered. Generally, hinges or gaps are used between the platforms of the two towers to adapt to different amounts of thermal expansion and avoid platform damage. 3) Architectural layout: Towers with a diameter of less than or equal to 1000mm can also be arranged within a frame, using the frame to improve its stability and set up platforms and ladders. But the pipes running down the tower need to avoid colliding with the beams at the openings in the frame. 2. Layout requirements: A. Planar layout distance requirements: 1) The distance between the tower and the pipe gallery arranged along the pipe gallery: If a pump is arranged between the tower and the pipe gallery, it should be determined according to the operation, maintenance and piping requirements of the pump. ； If there is no pump arranged between the tower and the pipe rack, the distance between the outer wall of the tower and the center line of the pipe rack column should not be less than 3m. 2) The distance between multiple towers must meet the needs of operation, maintenance channels and basic layout. The clear distance between two towers should not be less than 2.5m. B. Installation height requirements: (In principle, it is determined by the process) 1) When internal pressure or fluid gravity is used to send materials to other equipment or pipelines, it should be determined by its internal pressure and the pressure and height of the equipment or pipeline being sent. 2) When suctioning with a pump, the installation height of the equipment should be determined by the NPSH of the pump and the pressure drop of the suction pipe. 3) When there is a tower with non-open flame heating reboiler, its installation height should be determined according to the mutual relationship between the tower and the reboiler and the operation requirements of the process requirements. 4) The minimum clearance required for the installation and operation of pipelines at the bottom of the tower should be met to ensure the passage of people, and the foundation surface of the tower should not be less than 200mm above the ground. 4 Compressor pipeline layout (1) The compressor inlet and outlet pipeline layout should minimize the number of elbows to reduce pressure drop under the conditions of thermal compensation and the allowable pressure of the compressor nozzle. (2) Cut-off valves should be installed at both the inlet and outlet, and check valves should be installed on the outlet pipeline to prevent the flow of material from flowing back into the body when the compressor is switched or shut down due to an accident. (3) The compressor should be as close as possible to the upstream equipment, so that the compressor inlet pipe is short and straight. ； The inlet pipe should be connected from the top of the main pipe, and a manhole or detachable nipple should be provided ； When the suction medium is saturated gas, the inlet pipe should be insulated or traced. 5. Piping arrangement of vertical vessels Vertical vessels (including reactors) are generally arranged in rows. Therefore, piping with the same operation is arranged together at the corresponding position of the vessel to avoid incorrect operation and is safer. For example, when two containers are arranged in a row, the nozzles can be arranged symmetrically. When three or more containers are arranged in a row, each nozzle can be arranged at the same position on the equipment. For containers with stirring devices, the pipes shall not hinder the disassembly and maintenance of the stirrer. Description (a) of the schematic diagram of the pipeline layout of the vertical vessel indicates that the pipelines between two devices that are close to each other cannot be directly connected, but should be connected at a 45° or 90° bend. (b) The feeding pipe is placed in front of the equipment, making it easy to operate while standing on the ground (floor). (c) When the discharge pipe is laid along the wall, the distance between the equipment should be larger so that people can enter the equipment room for operation, and the distance from the wall can be smaller. (d) The discharge material is led from the front, and is immediately introduced underground after passing through the valve (through trenches or buried underground). The distance between the equipment and the distance between the equipment and the wall can be smaller. (e) When the diameter of the container is small and the bottom is high from the ground (floor), the discharge pipe should be led out from the center of the bottom. With this arrangement, the pipes are short and the floor space is small. (f) The feeding pipes of the two devices are arranged symmetrically, making it easier for people to operate while standing on the operating platform. 6. Pipeline layout of horizontal vessels. The pipe mouths of horizontal vessels are generally arranged in a straight line, and various valves are also installed directly on the pipe mouths. If the bottom of the container is higher than the operating table, the discharge pipe valve can be placed on the table and operated on the table. ； Otherwise, the discharge pipe valve should be arranged under the table, and the valve stem should be extended and extended to the table for operation. 7 Piping layout of centrifugal compressor The piping layout of centrifugal compressor must meet the following requirements: Pipe layout should comply with relevant design standards, specifications and regulations ； Comply with the requirements of process flow chart and instrument flow chart ； The pipeline layout should make the piping system have a certain degree of flexibility to ensure that the force and torque exerted by the pipeline on the compressor nozzle do not exceed the allowable value range of the compressor manufacturer. ； Pipe layout should consider setting up reasonable support points and matching types of pipe supports. ； The pipeline layout should be designed and planned to ensure the safe and reliable operation of the compressor, and at the same time, it should meet the requirements of construction, maintenance operations and other aspects. 1. Requirements for the layout of the inlet pipeline of the centrifugal compressor. When the centrifugal compressor is installed in a closed factory, the inlet pipeline is generally set outside the factory, which can save space and facilitate construction and maintenance. ； The compressor inlet generally cannot be directly connected to the elbow. Ensure that the shortest straight pipe section should be greater than 2 times the pipe diameter, usually 3 to 5 times the pipe diameter. According to the requirements of the flow chart, generally the inlet pipeline should be equipped with a gas-liquid separator, and the separation equipment should be as close to the inlet as possible. At the same time, consider that the pipeline has a certain slope to the gas-liquid separator. In order to prevent debris from entering the compressor before starting, a detachable short pipe is installed at the pipeline inlet to facilitate the installation of a temporary filter. 2. Requirements for the layout of the centrifugal compressor outlet pipeline. After pipeline stress analysis, if the outlet pipeline meets the compressor nozzle force and moment, a variable force spring support hanger is usually installed near the pipeline outlet. The appropriate form and type are determined according to the place where the pipeline support needs to take root. The load and plate size are uniformly considered based on the results of the stress analysis. ； The pipe at the outlet of the compressor cannot have a bag shape ； The outlet pipeline must generally have a check valve to prevent gas and liquid from flowing back. When the diameter of the pipeline is too large, the check valve should be as close as possible to the unit to prevent reverse flow from damaging the compressor. ； The relevant operating valves of the outlet pipeline should be arranged on the second floor platform of the compressor to facilitate the operator to operate and observe on-site instruments. ； While the pipeline layout meets the stress on the compressor nozzle, the direction should be as short as possible to reduce the number of elbows and reduce the resistance of the pipeline. 8. Pipeline layout of reciprocating compressors Reciprocating compressors are important equipment in refining and chemical plants. In their pipeline design, process pipeline layout is very important. In addition to meeting the process requirements of pipeline layout, they should also meet the anti-vibration requirements of pipeline layout. In the anti-vibration design, in addition to meeting the flexibility needs of the piping system, we must also try to control the pipeline vibration within a reasonable range. 1. Setting of the inlet liquid separation tank of the reciprocating compressor. The inlet of the reciprocating compressor is generally equipped with an inlet liquid separation tank, which mainly provides a stable air flow for the compressor so that the gas condensate in the inlet pipe can be separated in the inlet liquid separation tank to prevent liquid from being brought into the compressor cylinder. In order to reduce the pressure drop in the compressor inlet pipeline, the liquid separation tank is required to be arranged near the compressor in a location that is easy to operate and maintain. In addition, when two or more compressors share an inlet liquid separation tank, the positions of the compressors should be arranged symmetrically. The pipeline layout requires that the pipeline from the inlet separator tank to the inlet nozzle be the shortest, so that the pressure loss is minimized and there is no liquid in the pipe. 2. The layout of the inlet and outlet pipelines of the reciprocating compressor. There are two layout methods for the pipeline direction.: One is the overhead arrangement of pipelines. This arrangement method can avoid bag shapes in the pipelines and prevent fluid accumulation, but it requires a higher bracket, which is expensive and makes the operation of valves and instruments inconvenient. Generally, as long as a large amount of gas and condensate do not accumulate in the pipe, there is no need to adopt this arrangement. Another method is ground layout. Currently, it is commonly used in oil refining equipment. In order to prevent vibration, short pipe piers are often set up on the ground, and the pipes are laid along the ground. As shown in Figures 1 and 2, the pipes are laid on the pipe piers. The brackets are easy to install, which is beneficial to anti-vibration. ； Moreover, the installation height of valves and instruments is not high, making them easy to operate and inspect. However, the disadvantages of this arrangement are that there are many elbows, large inlet pressure losses, and liquid bags will appear on the pipelines. When liquid bags inevitably appear in the inlet pipelines transporting easily condensable media, in addition to taking measures to insulate and heat the pipelines to keep the gas temperature above the fog point, complete drainage facilities should also be set up 9 Pipe Gallery Pipe Layout Search The types of pipes laid on the pipe gallery are: Utility ducts, utility ducts, instrument ducts and cables. (1) The general layout of equipment is arranged on both sides of the pipe gallery in the order of the process flow. Therefore, the pipes connected to the equipment on the left side of the pipe gallery are arranged on the left side of the pipe gallery and the pipes connected to the equipment on the right side are arranged on the right side of the pipe gallery. Utility pipes should be arranged in the middle of the pipe gallery. (2) Heavy pipes with large diameters for transporting liquids should be arranged close to or above the pipe rack columns so that the beams of the pipe rack bear smaller bending moments. Small-diameter light pipes should be arranged in the center of the pipe rack. (3) For a double-layer pipe gallery, gas pipelines and hot pipelines should be arranged on the upper layer, and liquid, cold flow, and other pipelines with corrosive media should be arranged on the lower layer. Therefore, the steam, compressed air, gas and other process gas pipelines in the utility pipelines are arranged on the upper layer, and the layout of the remaining utility pipelines depends on the situation. (4) For public engineering pipelines such as steam and heat carrier oil with cut-off valves at the roots of branch pipes, their locations should be convenient for setting up valve operating platforms. (5) Low-temperature refrigeration pipelines, liquefied petroleum gas pipelines and other pipelines that should be protected from heat should not be arranged above hot pipelines or close to uninsulated hot pipelines. (6) If it is difficult for individual large-diameter pipes to enter the pipe gallery and change the elevation, they can enter with a flat turn. At this time, the pipe should be arranged at the edge of the pipe gallery. (7) Pipe corridors usually have a large number of valves at the entrance and exit devices. An operating platform should be set up, and the platform should be located above the pipes. If necessary, operation and maintenance channels should also be provided along the direction of the pipe gallery. (8) Along the outside of the pillars on both sides of the pipe gallery, small equipment such as regulating valve groups, heating steam distribution stations, condensate collection stations, sampling coolers, and filters are usually arranged. (9) When arranging the pipes in the pipe gallery, negotiate with the instrument professional to reserve a good location for the instrument trough. When the cable trough in the device is laid overhead, it is also necessary to consult with the electrical professional and reserve a good location for the cable trough. The layout of pipelines on the pipe gallery should determine the location of the pipelines based on the following factors:: 1. Factors of pipe diameter: Heavy pipes carrying liquids with large diameters (whether they are process pipes or utility pipes) should be arranged close to the pipe rack columns or above the pipe rack columns so that the beams of the pipe racks can withstand smaller bending moments. In particular, when individual large-diameter pipes enter the pipe gallery and it is difficult to change the elevation, they can enter with a flat turn. At this time, the pipe should be arranged at the edge of the pipe gallery. Small-diameter light pipes should be arranged in the center of the pipe rack. Since the span of small-diameter pipes is often smaller than the spacing of pipe racks, the location of these small pipes should also consider the use of large pipes to set up intermediate supports. For single-column pipe racks, the load on both sides of the pipe rack column should be balanced as much as possible. 2. Factors of equipment location: The more economical and reasonable equipment layout is to arrange equipment on both sides of the pipe gallery in the order of the process flow. Therefore, it is logical that the pipes connected to the equipment on the left side of the pipe gallery are arranged on the left side of the pipe gallery and the pipes connected to the equipment on the right side are arranged on the right side of the pipe gallery. Utility pipes should be arranged in the middle of the pipe gallery so that they can be easily led out to both sides. 3. Factors affecting the properties of conveyed materials: Low-temperature pipelines and material pipelines that are not suitable for heating, such as liquefied hydrocarbons, refrigeration pipelines, etc., should not be placed close to steam pipelines or uninsulated hot pipelines ； Oxygen pipelines should not be arranged adjacent to flammable gas or flammable liquid pipelines ； Pipes for corrosive media should be arranged on the lower level but should not be arranged directly above the driving equipment. For double-layer pipe corridors, the general principle is that utility pipes are arranged on the upper layer and process pipes are arranged on the lower layer. Usually gas pipelines, hot pipelines, and process pipelines with long laying distances should be arranged on the upper level. ； Pipes for liquid, cold, liquefied petroleum gas, chemicals and other corrosive media should be arranged on the lower floor. Therefore, steam, compressed air, nitrogen, oxygen, fuel gas, torch lines in utility pipelines, pipelines related to equipment on the top of the pipeline bridge and other process gas pipelines are arranged on the upper level ； Liquid utility pipes such as fresh water and circulating water are arranged on the lower or upper floors ； The process pipeline should be arranged on the upper or lower level depending on the elevation of the equipment nozzles connected to both sides, so that the pipeline is "step by step" or "step by step lower". When there is no regulating valve in the lower position, the pipeline must not appear in a bag shape. 4. Factors of thermal stress: Multiple pipes that need to use Π-type compensators to absorb thermal expansion should be arranged horizontally in groups. Pipes with larger diameters and higher temperatures that require larger Π-type compensators should be placed on the outside. Otherwise, they should be placed on the inside to facilitate the installation of Π-type compensators in groups. When the width of the pipe corridor is large, the position of the pipes that need to be compensated should be moderate to prevent the arm length of the bent pipe from being too long. Because the arms of the bent pipe are usually supported on the side beams of the pipe gallery. 10 Other pipeline layouts (1) A release valve is installed at the highest point of the pipeline and a purge valve is installed at the lowest point. The discharge pipeline valve should be close to the main equipment and the exhaust valve should preferably be directly connected to the equipment body. (2) A flame arrester should be installed on the pipeline that discharges flammable and explosive gases. The flame arrester on the exhaust pipe of the outdoor container should be placed 500mm away from the exhaust pipe interface (the port connected to the equipment). The exhaust from the indoor container must be connected to the roof. The flame arrester should be placed on or near the roof. The distance between the flame arrester and the exhaust port should not exceed 1m. (3) When setting up sampling points on the pipeline, a location should be selected that is easy to operate and where the sample taken out is representative and authentic. This article is reprinted in Qi Ge Talks about Safety