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Design specification of equipment layout for chemical plant
Part 5: Design technical specifications
1 General provisions
1.0.1 This part of this specification is formulated with a view to improving the engineering design quality of chemical plant and standardizing the technical requirements of equipment layout design.
1.0.2 This part is applicable to the equipment layout design of newly-constructed, extended or renovated process plants in the chemical industry. Petroleum, petrochemical, textile, pharmaceutical and other industries may refer to this part.
1.0.3 In addition to this part and the other four parts (HG/T 20546.1~HG/T 20546.4) of this specification, the equipment layout design shall also comply with those stipulated in the current relevant standards of the nation.
2 Layout of pump
2.1 Layout principle
2.1.1 The pump can be arranged in three ways: open-air, semi-open-air and indoor.
1 Open-air layout: it is generally concentrated in the lower part or on the side of the pipe rack, or scattered in the vicinity of sucked equipment or suction side equipment, which has the advantages of good ventilation and convenient operation and maintenance.
2 Semi-open-air layout: it is suitable for rainy areas. When the operating temperature of the pump is lower than the autoignition point, the pump is generally arranged below the pipe rack, and a canopy is set on the upper part of the pump pipeline. It may also be arranged on the ground under the frame, and the frame platform is used as a canopy. These pumps may be arranged in single, double or multiple rows according to the design layout requirements related to pumps.
3 Indoor layout: the pump may be arranged indoors in cold or windy areas. If the equipment is required to be arranged indoors according to the process, the pump to which it belongs shall also be arranged indoors.
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2.1.2 Centralized or decentralized layout.
1 Centralized layout refers to the centralized layout of pumps in the pump house or open, semi-open pipe rack or under the frame, in the form of single or double row layout. Where there are many tower equipment in the process flow, the pumps are often arranged under the pipe rack, and in the cold area, they are concentrated in the pump house.
2 Decentralized layout is to arrange the pump directly near the tower or vessels according to the process flow. When the number of pumps is small, the centralized layout is unreasonable from the perspective of economy, or the process has special requirements, or for safety reasons, the decentralized layout may be adopted.
2.1.3 Arrangement.
For the layout of the pump, first consider the convenience of operation and maintenance, and then pay attention to the tidiness and beauty. Due to the different models, characteristics and shapes of pumps, it is difficult to arrange them neatly. Therefore, when the pump group is arranged centrally, the following two arrangements are generally adopted:
1 The outlet of the centrifugal pump is aligned and arranged in parallel to make the outlet pipe of the pump neat and easy to operate, which is a typical arrangement of pumps.
2 One end of the pump may be aligned with the foundation when the outlet of the pump cannot be aligned, which is convenient for setting drain pipes or ditches.
2.1.4 When mobile lifting facilities cannot approach pumps and their drivers with large mass, fixed lifting facilities for maintenance, such as lifting beams, monorail cranes or overhead cranes, shall be set up. Sufficient space shall be reserved in buildings and structures under construction.
2.1.5 When the pump is arranged, the installation and operation position of the valve shall be considered.
2.1.6 The drainage ditch with cover plate shall be set at the foundation edge of the pump front. In order to prevent combustible gas from entering the drainage ditch, drainage funnel with water sealing and buried pipe may also be used to replace the drainage ditch.
2.1.7 The design of pump house shall comply with relevant requirements on fire prevention, explosion prevention, safety, hygiene and environmental protection, and measures such as heating, ventilation, lighting and noise control shall be considered.
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2.1.8 Hot oil pumps for conveying high-temperature media and pumps for conveying flammable, explosive or harmful (such as ammonia, etc.) media shall be arranged in an open or semi-open environment requiring ventilation.
2.2 General requirements
2.2.1 Layout of pumps under pipe rack.
1 When the air cooler is installed on the upper part of the pipe rack, if the operating temperature of the pump is less than 340°C, the center line of the pump outlet pipe should be 600mm to 1,200mm outside the center line of the pipe rack column. If the operating temperature of the pump is greater than or equal to 340°C, the pump shall not be arranged under the pipe rack.
2 When the air cooler is not installed in the upper part of the pipe rack, the center line of the pump outlet pipe is generally 600mm to 1,200mm inside the center line of the pipe rack column.
3 For the pump arranged under the pipe rack, its orientation is that the pump head faces the outside of the pipe rack and the driver faces the channel side under the pipe rack. See Figure 2.3.1 of this Part. However, when the bottom plate of a large pump is long, it may be arranged at 90° (i.e., along the longitudinal arrangement of the pipe rack).
4 For large installation pipe rack with large span (≥10,000mm), the layout of the centerline of pump outlet pipe may not be limited by paragraph 2 of this subclause.
5 Pumps arranged in rows shall be arranged according to fire prevention requirements, operating conditions and material characteristics; in case of open and semi open layout, combustible liquid pumps with operating temperature not less than the autoignition point shall be arranged in a centralized manner; a fire separation distance of not less than 4.5m shall be provided between combustible liquid pumps whose operating temperature is lower than the autoignition point; and a fire separation distance of not less than 7.5m shall be provided between liquid hydrocarbon pumps.
2.2.2 Maintenance and operating accesses of pumps.
1 See Clause 3 of Part 2 of this Specification for the width of the maintenance access of the pump and the clear distance between pumps and from the pump to the building (structure); the arrangement clearance of pumps in the structure may be designed with reference to the arrangement clearance of pumps in the building, as shown in Table 3.1.2 in Part 2 of this Specification.
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2 The width required for handling parts with a small forklift may be considered as the width of the overhaul access in front of the pump, which shall generally not be less than 1,250mm. For large pumps, the clear distance shall be appropriately increased.
3 Two identical small pumps may be arranged on the same basis, and the minimum distance between protruding parts of adjacent pumps is 400mm.
2.2.3 Layout of pumps in pump house.
1 If the pump house is close to the pipe rack, the column spacing should be the same as that of the pipe rack, generally 6m and 9m. The span is generally 4.5 m, 6m, 9m and 12m, which may be arranged in single or double row. See Clause 3 of Part 2 of this Specification for the clear distance.
2 The floor height of pump house (beam bottom elevation) shall be determined by the height required by lifting facilities for inlet and outlet pipelines and equipment maintenance, generally 4.0m to 5.0m.
3 The pump house in the tank farm is generally set outside the fire dike, and its distance from the outside of the fire dike shall not be less than 5m. The distance from flammable and explosive liquid storage tanks shall meet the requirements of GB 50160 Fire prevention code of petrochemical enterprise design.
2.2.4 Pump elevation.
1 The foundation surface of the pump should be 300mm (150mm in minimum) higher than the ground; When a filter is installed in front of the pump suction inlet, the height of the pump foundation shall consider that the filter can be easily cleaned and disassembled.
2 The relationship between the elevation of suction inlet of pump and the elevation of storage tank or tower equipment shall meet the requirements of NPSH.
3 When determining the elevation of pump suction inlet, it is generally required that the suction pipeline has no pocket. Materials that may produce polymerization must be completely discharged during parking. Therefore, the suction pipe is required to have a slope in the direction of the pump, and the elevation of the pump is determined according to this requirement.
4 The centrifugal pump for underground tank shall be generally installed at the same height as the underground tank.
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2.2.5 For occasions where mobile pumps need to be installed, centralized arrangement of pumps of the same type shall be considered, so that mobile pumps are located in areas that are easy to pass and do not hinder operation and maintenance operations. If it is necessary to replace a pump in the pump group with a mobile pump, the pump shall be left with a position for switching pipeline operation.
2.2.6 When the pumps in tank farm are arranged in the open air, they shall generally be set outside the cofferdam and fire dike, and their distance from flammable and explosive liquid storage tanks shall meet the requirements of GB 50160 Fire prevention code of petrochemical enterprise design.
2.3 Example of layout
2.3.1 See Figure 2.3.1 for the layout of indoor pumps.
2.3.2 See Figure 2.3.2 for the layout of pump under outdoor pipe rack (with air cooler).
2.3.3 See Figure 2.3.3 for the layout of pump under outdoor pipe rack (without air cooler).
1 General provisions
2 Layout of pump
3 Layout of tower
4 Layout of heat exchanger
5 Layout of air cooler
6 Layout of horizontal vessels
7 Layout of vertical vessels and reactors
8 Layout of heating furnace
9 Layout of centrifugal compressor
10 Layout of reciprocating compressor
11 Layout of the pipe rack in the equipment
12 Layout of outside pipe supports
13 Layout of rotary kiln
14 Layout of tank farm
15 Layout of loading and unloading station of tanker car and rail tanker car
16 Layout of filling station
17 Layout of flare and chimney
18 Design specification of plant layout
19 Design specification of anchor bolt of equipment
20 Design specification of transportation and lifting of equipment
21 Design specification of noise control
22 Design specification of electrostatic grounding
