Equipment purge issues

Pipes are generally purged with compressed air. For flammable media that are corroded by nitrogen or stainless steel, it is prohibited to use water with substandard chloride ion content for cleaning.

What are the purging plans and principles? ⒈Blow the main pipe first, then the branch pipes ； ⒉When the cold exchange line is cleaned, the tube and shell processes are carried out separately, one process is purged, and the other process is opened. ； ⒊When purging, try not to install orifice plates, meters, traps, nozzles, safety valves and regulating valves. ； ⒋Try to avoid moving equipment such as pumps and compressors.

Purge is divided into blast purge, air purge plan, water flushing plan and steam purge plan. The purging plan should be selected according to the purging requirements and purpose. I have uploaded the information. This post was last edited by ty000315 on 2009-3-7 18:31 ]

Break! The flange exiting the equipment must be disconnected, otherwise the blown items will enter the subsequent work section.

The water must be removed when cleaning the line, otherwise the water hammer may damage the pipeline if the water hammer is serious. In addition, the cold exchange equipment used for cleaning the line in one stage must be relieved of pressure in the other stage to prevent the equipment from holding pressure.

It is best to inspect the tank tower before sealing the manhole. It is difficult to clean the tank by manual cleaning only by purging afterwards. If there will be a long water transportation process after purging, the quality of container purging will not be so strict.

Be sure to remove purified water when cleaning the line to prevent equipment from being stressed.

3.3 Guidelines for Preparing a Manual Cleaning Plan for Pipelines/Equipments (Outline) 3.3.1 The Purpose of Manual Cleaning of Pipelines/Equipments 3.3.1.1 Clean up construction debris to ensure system cleanliness and prevent debris from clogging valves, pipelines and equipment and causing unexpected failures. 3.3.1.2 Shorten the purge time and improve the safety level of the purge process 3.3.1.3 Check whether temporary construction facilities in pipelines/equipment have been removed. 3.3.2 Determination of systems/equipment that require manual cleaning 3.3.2.1 Generally speaking, when the diameter of a pipe is greater than 500mm, its horizontal sections and pipe sections with a slope of no more than 45 degrees require manual cleaning. 3.3.2.2 For towers, tanks, reactors and other types of containers equipped with manholes and hand holes, manual cleaning must be carried out before the manholes and hand holes are sealed and airtight. 3.3. 3 Principles of manual cleaning of pipes/equipment 3.3.3.1 safety principles 3.3.3.3 .1 Pipelines/equipment containers must effectively isolate toxic and harmful gases and liquids, such as nitrogen, carbon monoxide, pure oxygen and hydrocarbons and alcohols. 3.3.3.1 .2 The oxygen, explosion and poisonous and harmful gases in the pipeline/equipment container are qualified, naturally ventilated, and meet the conditions for entering restricted spaces. 3.3.3.1 .3 Cleaning time and continuous operation time. It is recommended that the cleaning time be arranged in May-September.: 00 to 9: It will be held at 00, and it will be scheduled at 10 from November to February.: 00 to 14: 00, and the rest of the months will be scheduled at 8: 00 to 17: 00, cleaning workers shall not work continuously for more than 2 hours 3.3.3.1 .3 Implement protective measures for personnel entrance and exit to avoid falling from high altitudes 3.3.3.1 .4 Before operating, you must apply for the relevant operating permit, and you can only operate after obtaining the permit. 3.3.3.2 Sequence principle 3.3.3.2 .1 It is recommended that manual cleaning be arranged before the introduction of nitrogen, oxygen and other chemical materials into the device. 3.3.3.2 .2 Manual cleaning of pipelines should be arranged before chemical cleaning, pre-filming, and air/steam purging of the pipeline 3.3.3.2 .3 Manual cleaning of equipment containers should be carried out after the internal parts are installed and before the manholes and hand holes are closed. After cleaning, the manholes and hand holes should be closed immediately to prevent foreign matter from entering. ； If the equipment container is used as a debris collection container during purging, it must be manually cleaned after the system is purged. 3.3.4 Conditions for manual cleaning 3.3.4.1 .Except for the cleaning personnel entrance and exit, the construction of other parts has been completed. There is no construction work on the pipelines/equipment containers and their connected systems. 3.3.4.2 Communication equipment is in good condition and contact information is confirmed 3.3.4.3 Personnel entering pipelines/equipment containers and external monitoring personnel must be well trained and proficient in cleaning plans and emergency plans. 3.3.4.4 Complete personal protective equipment 3.3.4.5 All working tools are available 3.3.5 Materials required for manual cleaning 3.3.5.1 personal protective equipment 3.3.5.2 work tools 3.3.5.3 Emergency equipment and facilities 3.4. 6 Manual cleaning steps 3.3.6.1 The cleaning location should be clearly indicated on the piping diagram or equipment container structure diagram. 3.3.6.2 Personnel import and export 3.3.6.3 Cleaning out debris 3.3.6.4 Manual cleaning inspection 3.3.7 Manual cleaning qualification standards and inspection methods 3.3.7.1 Qualification standards for manual cleaning: There are no debris, sediment, welding slag, welding rods, rust and other mechanical impurities in the pipeline/equipment container, and there are no temporary construction facilities. 3.3.7.2 Inspection method: Visual inspection 3.3.8 Manual cleaning records 3.3.8.1 Record form pipe/equipment number cleaning time whether the cleaner is qualified or not the inspector 3.3.8.2 Digital photos retained The retained photos include the cleaned debris and the internal conditions of the pipes/equipment containers after cleaning 3.3.9 Hazard identification and environmental factor analysis 3.3.10 Temporary blind plate table Blind plate serial number Blind plate location Installation time Installation confirmation person Disassembly time Disassembly confirmation person 3.3.11 Basis for preparation of manual cleaning plan 3.4 Chemical cleaning/pre-filming (passivation) plan preparation guide (outline) 3.4.1 Purpose of chemical cleaning/pre-filming (passivation) 3.4.1.1 The main purpose of chemical cleaning: Remove scale, oil, rust and other dirt from industrial equipment through chemical steps such as alkali washing, neutralization, and pickling. For new equipment, the main tasks are decontamination, oil removal, and rust removal. 3.4.1.2 The main purpose of pre-filming (passivation): A uniform and dense passivation film is evenly formed on the inner walls of equipment and pipelines to protect equipment and pipelines from corrosion, achieve long-term safe operation, or meet the requirements of downstream processes and equipment facilities. 3.4.2 Scope of chemical cleaning/pre-filming (passivation) 3.4.2.1 Boilers and other steam generation systems 3.4.2.2 Industrial circulating water system 3.4.2.3 Systems that have strict requirements on mechanical impurities during operation, such as the lubricating oil system of large units 3.4.2.4 This plan does not include physical and chemical treatments due to special requirements for surface hardness and smoothness of the equipment during operation. Please refer to the patentee's requirements for such treatments. 3.4.2.5 This plan does not include chemical solvent cleaning, oiling and decontamination of materials that have special requirements to meet safety needs during operation (such as pure oxygen). Please refer to the patentee's requirements for this type of treatment. 3.4.3 Principles of chemical cleaning/pre-filming (passivation) 3.4.3.1 Equipment/Pipeline Protection Principles 3.4.3.1 .1 The wearing parts/wearing equipment during chemical cleaning in the system must be removed or isolated in advance. The wearing parts/wearing equipment include safety valves, instrument measuring components, moving equipment impellers, seals, etc. 3.4.3.1 .2 Winter antifreeze measures must be implemented in place. There must be no dead ends in the cycle. After the work is completed, it must be purged clean and protected by nitrogen. 3.4.3.2 Environmental Protection Principles Cleaning waste liquid must be effectively treated to prevent water pollution 3.4.4 Conditions that chemical cleaning/pre-filming (passivation) should meet 3.4.4. 1 The overall system construction is completed and system circulation conditions are met 3.4.4. 2 The chemical cleaning/pre-filming (passivation) construction team is in place and the plan is explained 3.4.4. 3 Public engineering conditions requirements, water, electricity, steam, wind, nitrogen 3.4.4. 4 Safety precautions are in place, including acid, alkali, scald, and anti-skid in winter. 3.4.4. 5 Environmental protection measures are in place. 3.4.4 6 Equipment participants are trained in place and are required to master the plan and emergency plan. 3.4.4.7 Complete communication equipment and smooth communication 3.4.4.7 Materials are in place 3.4.5 Materials required for chemical cleaning/pre-filming (passivation) 3.4.5.1 Temporary equipment and facilities 3.4.5.2 Chemical cleaning/pre-filming (passivation) chemicals 3.4.5.3 Inspection coupons and corresponding inspection instruments 3.4.5.4 Labor protection supplies 3.4.6 Chemical cleaning/pre-filming (passivation) implementation steps 3.4.6.1 Process setting, requiring illustrations with drawings 3.4.6.2 Main steps of chemical cleaning/pre-filming (passivation): Water rinsing, heating, degreasing treatment (alkali cleaning), rinsing, reheating, pickling, cooling, passivation, rinsing 3.4.6.3 Technical requirements for the implementation of each step, including chemical concentration composition, chemical cleaning/pre-film (passivation) liquid circulation flow, temperature, pressure, estimated operating time, and coupon inspection frequency 3.4.6.4 , Process treatment after chemical cleaning/pre-filming (passivation) 3.4.6.5 , Waste liquid treatment after chemical cleaning/pre-filming (passivation) 3.4.7 Chemical cleaning/pre-filming (passivation) qualification standards and inspection methods 3.4.7.1 If required by the patentee, equipment designer or manufacturer, it shall be implemented in accordance with the standards provided by the patentee, equipment designer or manufacturer, and its inspection methods shall also be implemented in accordance with the requirements of the patentee, equipment designer or manufacturer. 3.4.7.2 If there are no clear requirements from patentees, equipment designers or manufacturers, national standards or industry standards can be followed for iron and ferroalloy process pipes and equipment. (HG/T2387-92 Chemical Cleaning Standard for Industrial Equipment) 3.4.8 Chemical cleaning/pre-filming (passivation) recording step start time end time agent concentration/composition flow temperature pressure coupon inspection result recorder 3.4.9 Hazard identification and environmental factor analysis 3.4.10 Temporary blind panel table blind panel serial number blind panel location installation time addition confirmation person removal time removal confirmation person 3.4.11 Chemical cleaning/pre-filming (passivation) plan preparation basis 3.5 Guidelines for Preparing a Purging/Flushing Plan for Pipeline Systems (Outline) 3.5. 1 Purpose of Purging/Flushing The purpose of purging/flushing the pipeline system is to thoroughly purge/flush away the dirt, sediment, welding slag, rust scale and other mechanical impurities present in the system before chemical feeding, so as to prevent valves, pipelines and equipment from being clogged due to debris in pipelines and systems, resulting in unexpected failures. 3.5.2 Piping system purging/flushing scope 3.5.2.1 Process material pipelines, flare lines and dilution lines for all main processes 3.5.2.2 Equipment shell diversion, on-site liquid level gauge, instrument pressure primary valve and pressure pipeline 3.5.2.3 Factory air, instrument air, nitrogen, production water, domestic water, fire water, foam, steam, condensate systems and other public works, main lines and branch lines of fire protection facilities, and heat tracing lines, etc. 3.5.2.4 Main pipeline of circulating water system and its branch pipelines 3.5.3 Purge/flush principle of pipeline system 3.5.3.1 Media selection principles 3.5.3.1 .1 Factory air, instrument air, and nitrogen systems are purged with factory air 3.5.3.1 .2Production water, domestic water, fire water, and foam systems should be flushed with water 3.5.3.1 .3 Steam, condensate systems, and heat tracing pipelines are purged by steam. 3.5.3.1 .4 It is recommended to use gas purging for the main process material pipeline, flare pipeline and diversion pipeline. During operation, the material in the pipeline system is water or normal temperature naphtha and pipelines with a specific gravity above it can be flushed with water. 3.5.3.1 .5 Systems that have special requirements for water content before operation of the device cannot use steam purging or water flushing, otherwise the drying progress will be greatly affected. 3.5.3.2 Equipment/Pipeline Protection Principles 3.5.3.2 .1 The purging/flushing medium, flow rate, flow rate, pressure and other parameters and inspection methods must comply with the design and specification requirements. If the patentee, equipment designer or manufacturer has requirements and standards, these requirements and standards shall be followed. 3.5.3.2 .2 It is strictly prohibited for unqualified media to enter various fixed bed equipment such as pumps, heat exchangers, cold boxes, towers with internal parts installed, reactors/driers/adsorption beds with catalyst/desiccant/adsorbent filling completed, etc. 3.5.3.2 .4 Components on the pipeline such as orifice plates, flow meters, regulating valves, temperature measuring components, and safety valves should be removed or isolated and protected before purging to avoid damage during purging/flushing. In principle, the regulating valve in the system must not be used as a purge control valve. If the purge air volume needs to be controlled, other means should be used. 3.5.3.2 .5 Before purging/flushing and during purging/flushing, the pipelines, pipe supports, pipe supports, spring supports and hangers, and guides must be inspected in detail to confirm whether they are firm and reliable. The vents must be firmly fixed to avoid problems such as pipeline slippage, deformation, stress concentration, and even impact on connected equipment and steel structures during the purging process. 3.5.3.2 .6 For over-limit pipelines and equipment that need to be flushed with water, the impact of changes in medium density and volume ratio on the steel structure and equipment foundation during the water flushing process needs to be considered, and must meet the design requirements. If the post-installation hydraulic test is not considered in the design, static load calculations are required. 3.5.3.2 .7 After steam purging or water flushing of the piping system, anti-freeze and anti-condensation must be considered in winter. 3.5.3.3 Quality first principle 3.5.3.3 .1 Gas purging process system, the gas flow rate is not less than 20m/s, and the purging pressure is not higher than the operating pressure. The general requirement is 0.6-0.8MpaG. If the purging quality is high, the purging pressure can be appropriately increased. 3.5.3.3 .2 The water flushing flow rate must be more than 1.5 times the system's normal operation (100% load) flow rate. The recommended water flushing flow rate is 4.0-5.0m/s. 3.5.3.3 .3 The purging/flushing of the pipeline system must ensure that the system is connected and no dead ends are left. 3.5.3.3 .4 The steam purging flow rate should be more than 1.5 times the maximum flow rate (maximum load) of the system, and the pipeline must undergo hot and cold changes to promote the shedding of rust and other attachments on the inner wall of the pipeline to improve the purging effect. 3.5.3.3 .5 The person responsible for the purging/flushing quality acceptance work shall be assigned to the person who shall comply with the management system related to the production preparation of the Olefin Department. 3.5.3.4 safety principles 3.5.3.4 .1 Purge/flush work is generally carried out overlapping or simultaneously with the later stages of project construction. Purge vents must be clearly marked, forbidden areas must be demarcated, and protective measures must be set up to prevent purged impurities from injuring people or other equipment and facilities. 3.5.3.4 .2 The high-pressure steam purge vent should be equipped with silencer equipment 3.5.3.4 .3 When using the blasting purge method, care must be taken that the system cannot be overpressured, special attention must be paid to the safety of the blasting port, and relevant personnel must be reminded to avoid causing panic. 3.5.3.5 overall arrangement principle 3.5.3.5 .1 Purging/flushing work must be under unified command, and operations involving peripheral public engineering systems must be carried out under the unified command of production scheduling. 3.5.3.5 .2 Purging/flushing work is generally carried out in units and systems according to the principle of first main pipeline and then branch pipeline. 3.5.3.5 .3 It is recommended that high-pressure steam purging be carried out at night to avoid any impact on the completion of the construction. 3.5.3.5 .4 The air purge gas source for the ethylene plant process system is recommended to be an air-operated cracking gas compressor. The air purge gas source for other devices can be air compressor station air compressors and char air compressors. When arranging purging/flushing work inside the device, it is also necessary to make overall arrangements and use public works rationally to ensure quality and progress. 3.5.4 Conditions that should be met for purging/flushing of pipeline systems 3.5.4.1 The pipeline construction of this system has been completed. The pipelines, brackets, pipe supports, and spring supports and hangers have been carefully inspected and are in compliance with the specifications. There are no sliding obstacles in the guide. The spring fixing devices have been removed from the spring supports and hangers, and they are flexible in expansion and contraction. 3.5.4.2 Public engineering conditions for purging/flushing operations are available 3.5.4.3 The construction cooperation team is implemented and the contact information is determined 3.5.4.4 Temporary facilities are installed in place. Equipment and components that should be removed or isolated during purging/flushing have been removed or isolated. The removed equipment and components are properly kept. 3.5.4.5 Safety measures are in place and relevant personnel in the area are notified 3.5.4.6 Environmental protection measures are in place, the discharge path of water after water flushing is implemented, and the steam purging operation is approved by the local environmental protection department 3.5.4.7 Materials are ready 3.5.4.8 A purging/flushing operation command and coordination team has been established with personnel in place. They are familiar with the purging plans of the entire plant and each system of the device and the operation of public works, and have on-site command, coordination and emergency response capabilities. 3.5.4.9 The purging operation personnel are implemented, trained, and familiar with the purging/flushing plan and emergency plan. 3.5.4.10 Complete communication equipment and smooth communication 3.5.5 Required materials 3.5.5.1 Temporary equipment, facilities and pipe fittings 3.5.5.2 Bolts and gaskets required for disassembly and assembly, the reset gasket must be a formal gasket 3.5.5.3 Utility requirements 3.5.5.4 Inspect materials and supplies 3.5.5.5 Labor protection products 3.5.5.6 Emergency Supplies 3.5.6 Pipeline System Purging/Flushing Procedures 3.5.6.1 Purge/flush flow chart, which requires indicating the purge/flush steps, disconnection position, discharge point position, and temporary blind plate position. 3.5.6.2 Instructions for purge/flush steps. Text description of purge/flush steps is required. 3.5.6.3 Several process pipeline purging methods to choose from 3.5.6.3 .1 Through the purge method, connect the pipe to be purged with the system, use a large system to inflate, and discharge the entire system pipeline. You can choose the sequence when discharging. Generally, the main pipe is purged first, and then the branch pipes are purged. 3.5.6.3 .2 Segmented purging method divides the system pipeline into several parts, and each part is further divided into several sections, and then purged section by section. After purging, one section is isolated from the system. Suitable for situations where the air source is small. 3.5.6.3 .3 Explosion purging method requires special attention to safety when using this method. Generally used in large-diameter pipes or pipes where dirt is difficult to remove. When choosing the blasting purge method, you should calculate in advance and select the blasting membrane according to the system operating pressure. You can use plastic cloth, waste drawings or asbestos boards and other low-strength materials to replace the blind plate and install it at the purge discharge outlet. When the purge pipe reaches a certain pressure, the bursting membrane bursts, a large amount of airflow is ejected, and impurities are removed. 3.5.6.3 .4 Purge method for installing regulating valves on pipelines 3.5.6.3 .4.1 Replace the regulating valve with a temporary short pipe, and reset the regulating valve after cleaning. Suitable for situations where the pipe size is very large and the regulating valve does not have front and rear shut-off valves 3.5.6.3 .4.2 Remove the regulating valve, use the front and rear cut-off valves of the regulating valve to control the discharge, discharge the air on both sides respectively, and reset the regulating valve after cleaning. It is suitable for situations where the pipe size is small and the front and rear shut-off valves and bypass valves of the regulating valve are welded valves. 3.5.6.3 .4.3 Add blind plates or baffles on both sides of the regulating valve to prevent the purge material from entering the regulating valve. After the purging is completed, remove the blind plates or baffles, remove the short pipe between the regulating valve and the cut-off valves on both sides or directly remove the cut-off valve, and manually remove debris at the front and rear nozzles of the cut-off valve. Suitable for medium-sized pipelines, when the regulating valve, front and rear shut-off valves and bypass valves are all flange valves 3.5.6.4 When resetting the equipment, regulating valves, and instrument components removed before purging/flushing, they must comply with the design and installation requirements, and pay attention to the serial number and direction. The purge/flush plan is required to indicate its serial number and direction. 3.5.6.4 Antifreeze and anticondensation measures 3.5.7 Pipeline system purge/cleaning qualification standards and inspection methods 3.5.7.1 Process system air purge qualification standards: The system is clean, free of sand, rust and other mechanical debris, and no construction leftovers or discards such as welding wire, water-soluble paper, sponges, etc. Inspection method: Under normal purge flow rate, place a pure cotton white cloth target plate at the purge port. After 5 minutes, perform a visual inspection. It is required that the white cloth has no obvious discoloration and no traces of debris. 3.5.7.2 Steam purge qualification standards: The system is clean, free of sand, rust and other debris, and no construction leftovers or discards such as welding wire, water-soluble paper, sponges, etc. Inspection methods: Low-pressure steam pipelines use visual inspection of steam condensate, which requires the steam condensate to be clear and transparent ； Medium-pressure, high-pressure and ultra-high-pressure steam pipelines are inspected by target shooting. The target plate is a polished copper sheet or aluminum sheet, which is purged at a purge flow rate for 5 minutes. The target plate is required to maintain its original smoothness, and the damage points with a diameter of more than 0.2mm on the surface of the target plate should not exceed 3/square inch. 3.5.7.3 Water flushing qualification standards: The system is clean, free of sand, rust and other debris, and no construction leftovers or discards such as welding wire, paper scraps, sponges, etc. Inspection methods: Install a 60-mesh filter at the discharge port, and visually inspect the filter after flushing for 5 minutes. 3.5.8 Piping system purging/flushing records 3.5.8.1 Record table serial number, pipe number, purge/flush direction start time, end time, whether the purge operator is qualified or not, the inspector 3.5.8.2 Digital photos are retained to compare the photos of the target plate before and after purging, and photos of the debris after purging. 3.5.9 Hazard identification and environmental factor analysis 3.5.10 Temporary blind plate table, blind plate serial number, blind plate location, installation time, installation confirmation person, removal time, removal confirmation person, 3.5.11 Pipeline system purging/flushing preparation basis

The purge of the heat exchanger should be disconnected at the inlet flange and blocked with a blind plate close to the heat exchanger surface to prevent debris from blowing into the heat exchanger. After confirming that the inlet pipeline is purged clean, remove the blind plate and purge the upper flange of the heat exchanger. If it is welded, clean the pipeline before welding the inlet pipeline. Other equipment also cannot allow debris to enter the equipment.

When purging the tank tower, the manhole should be opened and people can enter for cleaning. The bottom valve of the tank tower that cannot be entered can be vented and purged. Pay attention not to blow the dust and particle impurities in the pipeline into the tank tower when purging the pipeline. However, the volume of the tank tower can be used to purge the pipeline.

Confirm by segmented purge and check with white board.

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