Engineering Management Technology Information Factory Compressed Air Pipeline Design and Construction 1 Ma Zhifeng (Dongguan Yongchang Construction Engineering Co., Ltd. Guangdong Dongguan 5 pipeline design and calculation and improper installation, will cause increased resistance along the way, will cause insufficient end pressure, will affect the service life of the pipeline Will affect the economics of the entire system and the reliability of the work.
Compressed air is widely used in factories. This article starts from the practical application, through the actual case, briefly describes the steps and key points of the design and construction of low-pressure compressed air pipeline, pays attention to practical application, and uses it for technical exchange!
The design and construction of a pneumatic pipeline of about 2300m2 expansion workshop undertaken by our company increases the gas consumption of the construction unit from 24m3/min to 32m3/min. The original conveying main pipe diameter is C150mm and the working pressure is 0.8MPa. For a certain volume, the wall diameter can reduce the friction loss. The economic diameter should be determined by the economic flow rate. The general compressed air flow rate of the plant supervisor takes the economical flow rate of 812m/s. Consider investing. High flow rate. Therefore, the formula (1): (1)d is the inner diameter of the pipe (mm); after calculating the inner diameter d of the factory area, ==237.81, it can be inferred that the inner diameter of the branch pipe of the expansion is 118.9mm. The thickness of the pipe wall is through the pipe. The gas pressure is determined. 0.8MPa is a low-pressure pipe, which is made of carbon steel seamless steel pipe. The wall thickness can be calculated according to the thin-walled formula: j is the weld coefficient, seamless steel pipe=1, straight seam welding C is added Wall thickness (including: wall thickness deviation, corrosion margin, processing reduction), for simplicity, usually when > 6mm, C.0.18; when S6mm, C = 1mm. After inspection of the construction unit of the compression pipe inner wall corrosion In the case of 15 years, the rust depth of the inner wall is 0.51.5mm. Because the compressed air pipeline has a long service time, the C value is calculated and calculated. The wall thickness of the plant supervisor is: In summary, the plant supervisor should adopt C 8; the branch supervisor should adopt Seamless steel tube for C127X4.5.
2 Gas storage capacity verification Because the output unit of the original air compressor station of the construction unit has dubbed a 10m3 gas storage tank, it is only used to stabilize the supply air pressure and not for storage function. Therefore, it can be checked according to the following formula: N is the parameter. The recommended value for the customers who use the gas volume is 12, and the recommended value is 3, which is frequent but the fluctuation of the upper and lower fluctuations is small. If the fluctuation is frequent and the fluctuation value is large, it is recommended to take the value above 4.
32/(8+1)=7.1m3, so the capacity of the original gas storage tank is still reasonable.
3 It is true that the pipeline layout is (1) The arrangement of the air pressure pipeline is generally tree-shaped and ring-shaped. In order to prevent the increase of the air volume of a certain branch when the sound is set or the production line is increased, it is recommended to adopt a ring shape to prevent the air pressure from being insufficient.
(2) Because it is in the workshop, and the workshop is dubbed with centralized pipe hangers, the compressed air pipe is laid overhead and fixed on the hanger.
(3) Install the main valve in front of the branch pipe, and install the DN15 nozzle every 0.5m in the rear pipe to set the sound gas, and install a compressed air to filter the oil-water separator with sufficient flow to ensure the pneumatic tools and equipment. Sound operation and extended life.
(4) The compressed air main road should avoid the phenomenon of sharp turn (the inner angle is less than 90*). The pipeline should have a slope of 0.0020.003 in the downstream direction. When the compressed air branch is the branch of the main road, the goose should be used. The neck is connected in a way to prevent the condensate in the main road from directly entering the branch pipe.
(5) Install a sewage outlet at the lower end of the branch line so that the dirt in the pipeline can be discharged when not going.
4 Compressed air pipeline construction 4.1 Construction quasi-tone work (1) Before the start of the project activity, it is necessary to plan the commencement of work and approve the approval of the relevant departments before proceeding with the construction activities.
(2) Understand the familiar drawings, technical materials and related standards and specifications.
(3) For the construction plan, you should read and inspect carefully, and do a good job of deepening the design. If there is any doubt, you should promptly discuss it. Once you find the problem, you should correct it in time, and do a good job with the design unit and the construction unit. jobs.
(4) Precisely necessary welding process card and welding process evaluation.
(1) Check the site, check whether the mounting position of the bracket crosses with other pipelines according to the construction drawing. “Check the civil infrastructure and check whether the coordinates and elevation of the construction drawing are consistent.
(2) The accumulative sound is good for the storehouse with sound, materials and tools, and the open fire operation area is drawn.
(3) Check the construction sound of the quasi-tone, and go to the on-site school to connect the power.
4.1.3 Pipe components and support members The components of the pipe and the hanger and hanger materials must have the manufacturer's quality certificate, and the quality should not be lower than the current national standards. It should conform to the design documents and conduct visual inspection.
4.2 Pipe welding, installation, inspection 1: Ma Zhifeng (1980,12,4―), male, Han nationality, Xiangtan County, Hunan Province, graduated from Guangzhou University in 2002 with a sound management major, now working in Dongguan Yongchang Construction Engineering Co., Ltd. Mechanical and electrical construction workers, education: junior college.
The relevant provisions of the "Technical Information Industry Metal Pipeline Construction and Acceptance Specifications" are carried out.
Pipe prefabrication According to the quantity, gauge, material and pipe fittings specified in the pipe construction drawing, and the pipe system number and the sequence number of each component are indicated by the single line icon.
The appearance of the weld should be well formed and the shape should be smooth. Cracks, unmelted, pores, slag inclusions, splashes, etc. are not allowed.
4.3 Piping system pressure test pipeline pressure test should comply with the "industrial metal pipeline engineering test before the sound: before the pipeline system pressure test, the construction unit, the owner and the relevant departments should jointly check and confirm the conditions.
Since the pipeline belongs to the low-pressure pipeline and is used for compressed air transportation, and belongs to the expansion project, the pipeline is laid overhead, so only the air pressure test is carried out, and the hydraulic test is not performed.
4.4 Piping system Purging and flushing piping system Pressure testing should be carried out after compressed air purging. The following requirements should be met before purging.
(1) Orifice plates, flange-connected regulating valves, throttle valves, safety valves, instrument parts, etc. shall not be installed. Corresponding protective measures shall be taken for valves and instruments that have been welded to the pipes.
(2) The sound and piping system that does not participate in the system purge shall be isolated from the purge system. (3) The purge pressure shall not exceed the design pressure of the vessel and piping system.
(4) The compressed air pipeline must be purged with compressed air containing no grease. The flow rate of the purge gas is greater than or equal to. (5) During the purge process, the pipeline shall be inspected with a white cloth or a white painted target at the discharge port. In 5 minutes, no rust and other debris on the target plate were combined.
(6) The order of purging shall be carried out in order for the main pipe, the branch pipe and the dredging pipe to be carried out in sequence. The blown goods shall not enter the sound-setting and piping system that has been cleaned and combined, and shall not discharge the polluted environment.
(7) The piping system that has been purged and merged should be restored to its original state in time, and the piping system purge record should be filled out.
4.5 The basic identification color, identification symbol and safety sign of the pipe painting and color marking road shall be implemented. The air pressure pipe shall be painted with gray. The paint should have a quality certificate from the manufacturer. Welds and their marks shall not be painted before pressure testing.
Uniform coating, uniform color, strong adhesion, no peeling, wrinkles, bubbles, pinholes and other defects. The coating is intact and free of damaging flow.
4.6 Handing over the handover (1) Handling the handover procedures with the owner in time after the completion of the project within the scope of the contract.
(2) Providing to the owner: pressure test, rigorous test, purge, concealed engineering record and safety device commissioning test record.
(3) Submit technical documents such as quality certificates, inspection records, welding work records, design changes and material substitution documents, and pipeline completion drawings to the owner.
(4) The requirements and styles of the documents for the delivery of work shall be in accordance with the provisions of the "Technical Documents for the Administration of Engineering Construction".
(Continued from page 151) The average removal rate of iron is as high as 78%. After testing, the divalent manganese ions are oxidized by microorganisms into tetravalent manganese ions and adsorbed on the surface layer of the filter material, while the ferrous ions are oxidized. The ferric ion is adsorbed on the surface of the biofilm, and the content of ferromanganese in the wastewater reaches the reuse standard, but it is a major defect of the method due to the long biological reaction time. Due to the large amount of voids in the biological activated carbon, the overall surface area is large, and the efficiency of microbial reproduction is high, so the degradation of organic matter is very high.
The test results show that the biological activated carbon treatment process can not only achieve high removal rate of manganese and iron, but also good removal effect on organic matter and turbidity. When the operation residence time is 45 min, COD, total phosphorus, ammonia nitrogen and turbidity The removal rate of the degree is as high as 55%, 44%, 85% and 43% respectively. Through long-time filtration, the microorganisms can fully oxidize and adsorb manganese and iron ions, so that the wastewater can reach the recycling standard.
4 Other technologies In addition to biological activated carbon technology, reverse osmosis technology in China's steel enterprises plays a large role in the advanced treatment and reuse of wastewater, and its energy-saving effect is very good. It utilizes the principle of membrane separation technology, and can effectively remove organic matter and microorganisms in wastewater by the principle of reverse osmosis. This technology has been matured and widely used in the steel industry.
5 Conclusion In summary, in the steel industry wastewater treatment, biotechnology is very efficient in the deep treatment of wastewater, reasonable control of processing conditions, the advantages of using biological activated carbon technology can achieve very good treatment results, improve the reuse rate of wastewater. With the continuous development of scientific research and technology, we will be able to overcome the shortcomings of the technology in use, so that the biological activated carbon process has been widely promoted.
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