Requirements for the layout of equipment in chemical plants

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There are 20 questions regarding the requirements for the layout of equipment in chemical plants, and to date no one has been able to answer them all correctly... Internal parameters for pipes and valves. Yesterday, chemical plants are equipped with a variety of devices; due to the large number of such devices and the specific characteristics of each one, there are specific rules and requirements for their layout. Additionally, the design of the pipelines connected to these devices is also extremely important. 1. What are the different layout methods for towers? The specific requirement regarding the arrangement of the towers is as follows: they should be arranged in a single row; this arrangement is generally preferred. When there are two or more towers or vertical containers on one side of the pipe gallery, their center lines should usually be aligned with each other. If two or more towers are equipped with a common platform, it is advisable for their center lines to be aligned or for them to be aligned along tangential lines ； For towers with a small diameter but great height, they can be arranged in a single row; for others, a double-row or triangular arrangement is possible. In this way, platforms can be used to connect the towers together, thereby enhancing their stability. However, slidable guide nodes should be used for the platform’s root components to accommodate the effects of thermal expansion at different operating temperatures ； In a framed layout, for towers with a diameter of DN≤1000mm, they can also be arranged inside the frame or on one side of it. Improve its stability using a framework, and install platforms and ladders. For segmented towers installed on the framework, when motorized lifting equipment cannot be used, maintenance lifting facilities should be provided on the framework. 2. What are the requirements for the layout of the tower and its associated equipment? Layout requirements for the tower and its associated equipment: The tower and its related equipment, such as feed heaters, reboilers that use non-flame heating, top condensers, reflux tanks, bottom extraction pumps, etc., should be arranged in sequence according to the process flow. If necessary, an independent operating system can be established within a specific area, which facilitates operation and management. 3. How is the distance between the towers and vertical pipe fittings arranged along the pipe gallery and the pipe gallery itself determined? The distance between the towers and vertical vessels arranged along the pipe gallery and the pipe gallery itself shall be determined in accordance with the following requirements: When pumps are installed between the towers and the pipe gallery, this distance shall be determined based on the requirements related to the operation, maintenance, and piping of those pumps ； When no pumps are installed between the tower and the pipe tray, the distance between the outer wall of the tower and the centerline of the pipe tray columns should not be less than 3 m. 4. How is the distance between towers or between a tower and other adjacent equipment determined? The distance between towers or between a tower and other adjacent equipment must not only meet the requirements for the layout and installation of pipelines, platforms, instruments, and small equipment, but also satisfy the needs for operating and maintenance access as well as foundation layout. The clear distance between the two towers should not be less than 2.5 m. 5. What requirements should be met regarding the installation height of towers and vertical vessels? When using internal pressure or the gravity of a fluid to convey materials to other equipment or pipelines, it shall be determined by the internal pressure as well as the pressure and height of the equipment or pipelines to which the materials are being conveyed ； When pumping liquid, the installation height of the equipment should be determined by the pump’s net positive suction head and the pressure drop in the suction pipeline ； For towers equipped with heavy reactors heated by non-flame means, their installation height should be determined based on the relationship between the tower and the reboiler as required by the process, as well as the operational requirements ； The minimum clearance required for the installation and operation of the pipes at the base of the tower must be satisfied, and the foundation level of the tower should be at least 200 mm above the ground level. 6. What are the general requirements for the layout of heat exchange equipment? General requirements for the layout of heat exchange equipment are: (1) Shell-and-tube heat exchange equipment associated with the distillation tower, such as the reboiler at the bottom of the tower and the condenser at the top of the tower. The processes should be arranged in sequence near the distillation tower ； (2) The heat exchanger where two types of materials exchange heat should be located at the point closest to the pipes connecting the inlets and outlets of the two materials ； (3) A shell-and-tube heat exchanger in which one fluid exchanges heat with several different fluids should be arranged in groups ； (4) Coolers used to cool several groups of different materials with water or refrigerant should be arranged in groups ； (5) For heat exchange equipment arranged in groups, it is advisable to align the center lines of the support foundations. When the spacing between the supports is different, it is preferable to align the center lines of the support foundations at one end. To facilitate pipeline connection, the heat exchangers installed on the ground can also have their tube side inlet and outlet nozzles aligned along the same centerline ； (6) Heat exchange equipment should be arranged on the ground whenever possible; however, when there are many such units, they may be placed on structures. When floating-head heat exchangers are installed on the ground, the following requirements must be met: There should be a clearance of at least 0.6 m in width on both sides of the floating head and the tube box. Additionally, there should be a clearance of at least 1.2 m in width in front of the floating-head end ； In front of the tube box, starting from the end of the tube box, there should be a space that is at least 1.5 m longer than the length of the tube bundle. When floating-head heat exchangers are arranged on a frame, the following requirements must be met: the clear height of the platform in front of the floating-head end should not be less than 0.8 m; the clear height of the platform in front of the tube box end should not be less than 1 m. The platform shall be equipped with removable railings, and space required for removing the tube bundle must also be taken into account ； The height of the framework should be sufficient to accommodate the lifting of the tube box and the head cover of the float head of the heat exchanger. (7) To save space or facilitate operational procedures, two heat exchange units can be arranged one on top of the other. However, for two-phase flow media or heat exchangers with a shell diameter of 1.2 m or more, overlapping arrangements are not advisable ； (8) The clear distance between heat exchangers, as well as between heat exchangers and other equipment, should not be less than 0.7 m ； (9) Heat exchange equipment for heavy oil products or environmentally hazardous materials should not be installed on structures ； (10) Above heat exchangers whose operating temperature is above the auto-ignition point of the material, no other equipment should be installed if there is no floor or platform to separate them. 7. What are the general requirements for the layout of a reboiler? The general requirements for the layout of reboilers are as follows: (l) The distance between a reboiler heated by an open flame and the tower should be arranged in accordance with the distance requirements specified in fire safety regulations for heaters and towers ； (2) Horizontal reboilers heated by steam or a heat carrier should be located near the tower, maintaining a certain height difference from it (determined by the process design); the distance between them must meet the requirements for pipeline layout, and one end of the reboiler’s tube bundle should provide space and access for maintenance ； (3) Vertical reboilers should be supported by a tower and installed on the side of the tower, maintaining a certain height difference from it (determined by the process design). Sufficient maintenance space should be left above it ； (4) When multiple vertical reboilers are connected in parallel for a tower, their locations and installation heights must, in addition to meeting process requirements, also satisfy the layout requirements of the inlet and outlet manifolds, as well as facilitate operation and maintenance. 8. What are the general requirements for the layout of air coolers? The general requirements for the layout of air coolers are: (1) Air coolers (hereinafter referred to as air coolers) should be placed on the downwind side relative to the direction of the wind with the lowest frequency throughout the year at the facility ； (2) The air coolers should be installed above the main corridor, on the top layer of the framework, or at the top of the tower ； (3) Air coolers should not be installed above equipment for which the operating temperature is equal to or higher than the auto-ignition point of the material, as well as above equipment used for transporting and storing liquefied hydrocarbons ； Otherwise, non-combustible material partitions should be used for separation and protection ； (4) When multiple sets of air coolers are arranged together, they should be arranged in a consistent pattern; a row-based arrangement is preferred ； It should be avoided to have one part arranged in rows while another part is arranged in columns ； (5) For inclined-top air coolers, the ventilation surface should not be oriented toward the dominant summer wind direction. Slant-roof air coolers should be arranged in rows; when arranged in rows, there should be a space of no less than 3 meters between the rows ； (6) The distance between the frame columns of two humidified air coolers or combined dry-wet air coolers arranged side by side shall not be less than 3 m ； (7) Platforms should be provided at both ends of the air cooler tube bank’s tube boxes as well as at the location of the driving machinery ； (8) Sufficient maintenance space and access paths should be provided on the ground adjacent to the frame or main corridor of the air cooler. 9. How is the layout of the air coolers designed to avoid thermal air circulation within them or between them? How is the layout of air coolers designed to avoid thermal air circulation within them or between them? (1) Air coolers of the same type are arranged at the same height ； (2) Adjacent air coolers are arranged closely together ； (3) The grouped dry forced-air coolers and the induced-air coolers shall be arranged separately; the induced-air coolers should be located on the downwind side of the wind direction with the lowest frequency throughout the year for the forced-air coolers ； (4) When air-coolers of the induced-air type and those of the forced-air type are arranged together, the tube bank of the forced-air type air-cooler should be raised. 10. What are the general requirements for the layout of heating furnaces? The general requirements for the layout of heating furnaces are: (1) Open-flame heating furnaces should be centrally located at the edge of the facility, near fire-fighting access routes, and should be situated on the downwind side relative to the direction of the wind with the lowest annual frequency, taking into account equipment handling combustible gases, liquefied hydrocarbons, and Class A and B flammable liquids ； (2) The heating furnace and other open-flame equipment should be located together ； (3) Several heating furnaces can be arranged in a row, aligned along their centerlines. The clear distance between the two heating furnaces should not be less than 3 m ； (4) When using mobile maintenance equipment to lift the heater tubes, there must be passages for the mobile maintenance equipment to travel through, as well as maintenance areas. For heating furnaces with horizontal furnace tubes, on the side where the tubes are removed, the length of the maintenance area should not be less than the length of the furnace tubes plus 2 meters ； (5) The distance between the outer wall of the heating furnace and the edge of the maintenance road should not be less than 3 m ； (6) For heating furnaces equipped with steam generators, the steam drum should be installed at the top of the heating furnace or on an adjacent framework ； (7) The distance between the heating furnace and its associated fuel gas separation tank and fuel gas heater should not be less than 6 m ； (8) When the heating furnace is equipped with auxiliary equipment such as air preheaters, blowers, and exhaust fans, the layout of these auxiliary devices should not prevent the maintenance of both them and the heating furnace itself ； (9) The fire separation distance between the heating furnace and the liquefied hydrocarbon equipment installed outdoors shall not be less than 22.5 m. If a solid wall made of non-combustible material is installed between the equipment, this distance may be reduced, but it must still be no less than 15 m. The height of the solid wall should not be less than 3 m, and it should be no more than 5 m away from the heating furnace; it must also prevent combustible gases from entering the furnace ； When the wall facing the heating furnace in the building housing the liquefied hydrocarbon equipment or the Class A gas compressor room is a closed wall, the distance between the heating furnace and the building can be reduced, but it must not be less than 15 m. 11. What are the requirements for the layout of vertical containers? The shape of a vertical container is similar to that of a tower, except that its internal structure is less complex than that of a tower. The layout and installation height of vertical containers can follow the requirements applicable to towers; in addition, the following considerations should also be taken into account: (1) For ease of operation, vertical containers can be installed on the ground, floor slabs, or platforms, or they can pass through floor slabs or platforms and be supported on them using brackets ； (2) When a vertical container is installed through a floor or platform, efforts should be made to prevent the liquid level indicators and control instruments on the container from also passing through the floor or platform ； (3) In vertical containers, in order to prevent the solidification of viscous materials or the settlement of solid materials, and when there are high-capacity mixers inside, support structures should be installed as close to the ground as possible in order to avoid vibration effects ； (4) For vertical vessels with an open top, when manual charging is required, the height of the charging point should not exceed 1 m above the floor or platform. If it does exceed 1 m, it is necessary to provide a charging platform or steps. 12. What are the requirements regarding the layout and installation height of horizontal vessels? The layout and installation height of horizontal vessels must meet the following requirements: (1) Horizontal vessels should be arranged in groups. Horizontal containers arranged in groups should be aligned along the centerline of the support foundation or along the tangent to the head. The clear space between horizontal containers can be taken as 0.7 m. (2) When determining the dimensions of horizontal vessels in process design, it is advisable to use vessels of the same length but different diameters to facilitate equipment layout. (3) When determining the installation height of horizontal vessels, in addition to meeting requirements such as gravity flow of materials or pump suction height, the following requirements must also be met: When there is a sump beneath the vessel, sufficient space must be provided for the operation and monitoring instruments related to the sump ； When an operation passage is required below the container, the clearance between the piping at the bottom of the container and the ground should be no less than 2.2 m ； When horizontally oriented vessels of different diameters are arranged in groups on the ground or on the same floor or platform, the elevation of the centerline of the smaller-diameter vessels may be appropriately raised so that it matches the elevation of the top surface of the shell of the larger-diameter vessels, facilitating the construction of a common platform. (4) When horizontal containers are installed in a pit, proper measures must be taken to deal with water accumulation in the pit as well as the buildup of toxic, flammable, and explosive substances. The dimensions of the pit should meet the requirements for the operation and maintenance of the container. In rainy areas, it is advisable to consider installing a canopy above the pit. (5) The design of the platform for horizontal containers should take into account operations such as manholes and level gauges. The elevation of the top platform should be 150 mm lower than the flange surface of the top nozzle. When the height of the upper interface of the level gauge from the ground or operating platform exceeds 3 meters, the level gauge shall be installed near a straight ladder. A combined platform can be provided for horizontally arranged containers that are placed together. 13. What are the various ways of arranging pumps? There are three ways to arrange pumps: open-air arrangement, semi-open-air arrangement, and indoor arrangement. (1) Outdoor placement: Pumps placed outdoors are usually grouped beneath or to the side of pipe racks; they may also be scattered near the equipment they serve. Its advantages are good ventilation, as well as ease of operation and maintenance ； (2) Semi-outdoor layout: Pumps in a semi-outdoor layout are suitable for rainy areas; generally, the pumps are installed beneath pipe galleries, with canopies placed above the pipes. Alternatively, the pump can be placed on the lower floor of the framework, using the framework platform as a canopy. These pumps can be arranged in a single row, double row, or multiple rows, depending on the design requirements related to the pump ； (3) In indoor installations in cold or windy/sand-prone areas, the pump can be placed indoors. If the process requirements dictate that the equipment be installed indoors, then the pumps associated with it should also be installed indoors. 14. What are the specific requirements for pump layout? The specific requirements for the arrangement of pumps are as follows: (1) Pumps arranged in rows should be grouped according to fire protection requirements, operating conditions, and material properties ； When the pump is installed in an open or semi-open area ； Pumps for flammable liquids whose operating temperature is equal to or higher than their autoignition point should be installed in a centralized manner ； There should be a fire separation distance of not less than 4.5 m between such pumps and combustible liquids whose operating temperature is below their auto-ignition point ； There should be a fire separation distance of not less than 7.5 m from liquid hydrocarbon pumps ； (2) When pumps are arranged in rows, it is advisable to position the pump outlets at the end. Align the population centerline, or align the pump end foundation edge line ； (3) When pumps are arranged in two rows, it is advisable to position the power ends of the two rows opposite each other, leaving a maintenance passage in between ； (4) When the pump is located below or outside the main corridor, the minimum clear width of the passage in the pump area shall be 2 m, and the minimum clear height shall be 3 m. The width of the operation passage in front of the pump shall not be less than 1 m ； (5) When the pumps are located below or outside the pipe gallery, whether in a single row or double row, the centerlines of the pumps and drives should be perpendicular to the direction of the pipe gallery ； (6) When pumps are installed indoors, the clear distance between the two rows of pumps should not be less than 2 m. The clear distance between the pump end or the side of the pump and the wall should meet the requirements for operation and maintenance, and should not be less than 1 m ； (7) Except for small pumps installed on a common foundation, the clear distance between the two pumps should not be less than 0.7 m ； (8) The base surface of the pump should be 200 mm above the ground level. The minimum value must be no less than 100 mm ； When installing a filter in front of the pump’s suction inlet, the height of the pump foundation should take into account the ease of cleaning and removing the filter ； (9) When vertical pumps are installed below the main corridor or beneath the framework, space should be left above them for the installation and maintenance of the pumps ； (10) Transport of highly hazardous substances (such as propylene?) Pump rooms for substances such as hydrocyanic acid should be separated from other pump rooms ； (11) The fire pump room shall be equipped with dual power sources ； (12) The utility standby pump should be located in the middle of the corresponding pump ； (13) The layout of the pump should take into account the requirements for flexible piping design. 15. What are the general requirements for the layout of compressors? The general requirements for the layout of compressors are as follows: (1) The layout of the compressor unit and its associated equipment shall meet the requirements of the manufacturer ； (2) The compressor should be located near the equipment to be pumped, and its auxiliary equipment should be placed close to the unit ； (3) The layout of combustible gas compressors shall meet the following requirements: The distance from open-flame equipment and non-explosion-proof electrical equipment shall comply with the provisions of the current standards **\"Code for Design of Electrical Installations in Explosive and Flammable Environments\" GB 50028 and \"Code for Fire Protection Design of Petrochemical Enterprises\" GB 50160 ； It is suitable for outdoor or semi-open placement. In cold or windy/dusty areas, it can be installed inside a factory building ； Gas compressor plants of Class A with a single-unit drive power of 150 kW or more should not share the same building with other rooms of Classes A, B, or C ； Above the compressor, no equipment containing Class A, B, or C liquids shall be installed, except for high-mounted lubricating oil tanks for internal use, which are exempt from this restriction. (4) For compressors arranged in a single layer, when the foundation is at a high level, an operating platform should be provided as needed ； When there are many auxiliary devices, it is advisable to arrange them in two layers. 16. What requirements should the installation height of the compressor meet? The installation height of the compressor should be determined based on its structural characteristics. The installation height of the compressor, with its inlets and outlets at the bottom, shall meet the following requirements: (1) Requirements regarding the clearance between the inlet and outlet pipes and the ground ； (2) Requirements for the connection height between the import/export connection pipes and the pipes in the pipe tray ； (3) Requirements for the installation height and dimensions of the filter on the intake pipeline ； (4) To reduce vibration, the installation height of the reciprocating compressor should be lowered. 17. What fire protection regulations must be followed regarding the layout of the control room, power distribution room, and laboratory in the facility? What fire protection regulations must be followed regarding the layout of the control room, power distribution room, and laboratory in the facility? (1) The control room and the power distribution room should be located on the ground floor of the building; however, if production requirements or other constraints exist, they can be placed on the second floor or higher ； (2) In installations where flammable gases that are heavier than air may be released, the indoor floors of control rooms, power distribution rooms, and laboratories shall be at least 0.6 m higher than the outdoor ground level ； (3) The exterior wall of the control room facing the equipment side with fire hazards shall be a solid wall made of non-combustible material, without any doors, windows, or openings ； (4) Online analytical primary instruments for combustible gases, liquefied hydrocarbons, and combustible liquids shall not be installed inside control rooms or laboratories. When the aforementioned instruments are installed in rooms adjacent to the control room and laboratory, the partition wall between them should be a fire wall. 18. What requirements should be met for the layout of passages in production facilities? What are the minimum width and minimum clear height of the passages within the device? When arranging the equipment, necessary passages and areas should be considered comprehensively based on the requirements for construction, maintenance, operation, and fire safety. Inside the facility, application roads divide it into equipment and building areas with a floor area not exceeding 10,000 m2. When the floor area of the esterification polymerization, spinning, and post-processing facilities for synthetic fiber production exceeds 10,000 m2, passageways should be provided on both sides of them. The main traffic passage within the facility should be connected to the factory roads. (1) The installation of fire access routes in the facility shall meet the following requirements: When the width of the facility exceeds 60 m, a through fire access route shall be provided within the facility ； If the width of the facility is 60m or less and there are fire access routes on both sides of the facility, a continuous fire access route may not be required. Non-through roads within the facility should be provided with turnaround areas. The width of the road should not be less than 4m; the clear distance between the pipe rack on the road shoulder and the edge of the road surface should not be less than 1m. The inner turning radius of the road surface should not be less than 7m, and the clear height above the road surface should not be less than 4.5m. (2) The maintenance access path shall meet the requirements of mechanical maintenance equipment regarding road width, turning radius, and load capacity, and shall lead to the lifting holes for equipment maintenance. (3) The main vehicle passages, fire escape routes, and maintenance passages within the facility should be arranged together. (4) The operation pathways should be determined based on the frequency of production operations, routine inspections, minor repairs, etc., as well as the distribution of the operation points. 19. What considerations should be taken into account when designing the pipeline layout along the tower? The following 5 points should be considered in the layout design of pipes along the tower: (1) It should meet the requirements of the process piping and P&ID ； (2) The pipeline layout should be planned from the top to the bottom of the tower, starting with the location of the pipes at the top of the tower and those of large-diameter pipes, as well as the direction of gravity-fed pipes. After that, pressure pipes and ordinary pipes should be arranged, and finally, the pipes at the bottom of the tower and those of small diameter should be considered ； (3) Consideration should be given to ease of operation, maintenance, safety and reliability, as well as economic Reasonableness ； (4) Each pipeline should be as short as possible according to its starting and ending points, but it must still meet the requirements regarding pipeline flexibility ； (5) Each pipeline should be arranged as much as possible along the tower, with attention paid to achieving a \"good appearance\": Two options can be considered: one is to arrange each pipeline separately ； Second, arrange the pipes in groups (when the concentrated load resulting from this method is high, approval from the equipment designer must be obtained) ； They are arranged in concentric circles along the outer wall of the tower on the pipeline side, or tangentially along the outer wall of the tower. 20. What are the key points in the design of tower top pipelines? The key points of the top of tower piping design are: (1) The top of tower piping generally includes pipelines for the oil and gas at the top of the tower, venting, and safety valves. The tower top vent pipe is generally installed at the top of the horizontal section at the highest point of the oil and gas pipes in the tower, and must comply with the requirements of fire protection regulations ； (2) The medium in the oil and gas pipelines at the top of the tower is generally in gaseous form. The pipe diameter is large, the pipes should be as short as possible; they should have a gradual descent in elevation, bag-shaped sections should be avoided, and the pipes must possess a certain degree of flexibility ； (3) For each pipe running along the tower, a load-bearing support must be installed at the upper part, and guide supports must be placed at appropriate locations to prevent excessive stress on the pipe nozzles ； (4) The oil and gas pipelines at the top of the distillation tower are generally not insulated, only protected from heat ； If there are multiple heat exchangers connected to this pipeline, they should be arranged symmetrically in order to avoid flow imbalance ； (5) When the tower top features two-stage condensation, the piping layout should ensure that the condensate flows by gravity stage by stage. The main oil and gas pipeline and the inlet branches for the condensation circuit should be arranged symmetrically to achieve uniform flow rates ； (6) When the top pressure of the tower is controlled by a thermal bypass, the tubes of this bypass system should be insulated, and their length should be kept as short as possible. The control valve for this system should be installed above the reflux tank, and there should be no \"pouch-shaped\" sections in the pipes to prevent liquid from accumulating ； (7) The oil and gas pipes at the top of the vacuum tower are welded directly to the tower opening rather than connected using flanges, in order to reduce leaks