Purge scheme for the equipment. . .

I really have no idea. For several of our projects, after the water washing process and before starting up the machinery, we purge the entire system with steam. There are no detailed procedures for this; basically, the pressure is gradually released from low to high levels, and bolts at steam traps and certain shut-off valves are removed. After washing with water at room temperature, there is no need for steam purging. That’s what I do on site; perhaps the processed tripe was already ready, and since a large quantity was involved, we carried out the purging and rinsing tasks before adjustment in a rather casual manner. As for the detailed steps, I’ve never done them nor paid any attention to them; I just randomly pick a document to show to the client. After saying so much, actually I just want to know, moderator, will the wealth points be given?

Haha, the reward for replying is 2 wealth points, which you’ve already received. :lol

Instrumentation or safety valves, etc., need to be removed during purging.

During purging, ensure that gas flows from high to low pressure. Use containers such as tanks as the gas source; the storage tank must be pressurized before purging the pipelines located at lower elevations

Remember to remove the control valve, and a target testing must also be done! !

I. Purging objectives, requirements, and precautions for the unit 1. Purging objectives: To remove debris such as sediment, welding slag, and rust remaining in the equipment and pipelines from the construction phase of the unit, so as to enable the unit to be tested and its operational procedures can be verified, and to assess the quality of the unit’s construction. 2. Selection of purging medium: The medium used for purging process pipelines and equipment should be selected based on the specific processes and conditions of the equipment involved. This plan stipulates the following: (1) Circulating water, fresh water, demineralized water, softened water, and fire-fighting water shall be flushed with their respective media. (2) The 1.0MPa steam and condensate systems are purged using 1.0MPa steam. (3) For the 0.8MPa and 2.5MPa nitrogen systems, the purification air and non-purification air systems are purged using their own media. (4) For the process pipelines and equipment in the hydrogenation, desulfurization, conversion, medium-temperature shift, and PSA sections of the unit, unpurified air is used for purging. (5) The 3.5MPa steam system uses its own medium for target shooting. (6) The fuel gas system and the low-temperature vent system are purged with unpurified air. (7) The dirty oil system and naphtha system are purged using 1.0 MPa steam. (8) The acidic water system SR-103 to the outlet device is purged with 1.0 MPa steam, while the remaining parts are purged with non-purified air. 3. Purging methods and requirements: (1) Before purging and flushing, do not install items such as orifice plates, meters, traps, nozzles, filters, safety valves, and control valves, as well as the valve at the base of the instrument pressure lead, the handwheel valve of the pressure gauge, the connection valve of the level gauge, the sampling valve, and the shut-off valve before the safety valve. After the main pipeline has been thoroughly purged, start purging each section one by one. The installed check valves should be removed first, as well as any shunts or filters; these items should be taken out before the pipeline is purged again and then reinstalled. (2) In principle, the purging process must use the purge and flushing medium supplied at the gas (steam) and water supply points indicated in the purging procedure; however, appropriate adjustments can be made based on the actual conditions on site, as long as the quality of purging is maintained. (3) The purging process should, as much as possible, follow the principle of purging the main pipes first and then the branch pipes, moving downward or horizontally along the pipelines, while avoiding purging in the upward direction. (4) It is strictly prohibited to blow dirt into the equipment. If a cleaning medium must pass through the equipment, the short section or flange before it enters the equipment must be disconnected first; the inlet end of the equipment should be covered before blowing, and the inlet pipeline must be cleaned thoroughly before the medium can pass through the equipment. Steam cannot pass through the pump body. (5) Before purging, the process should be carefully inspected. The disassembled flanges must be fitted with metal sheets to prevent contaminants from entering the equipment or pipelines, which could affect the effectiveness and quality of the purging. (6) To enhance the purging effect, pressure holding and blasting methods can be employed (the held pressure must not exceed the operating pressure of the equipment). After purging for a certain period, the amount of purging medium can be quickly reduced and then rapidly increased again. This is very effective in removing debris from dead corners or within vertically ascending straight pipe sections. (7) Purging should be carried out in segments as much as possible; although this increases the workload of installing and removing flanges, it results in higher quality purging. Blow out one section, connect the next, and short-circuit some parts as needed, continuing in this manner until the entire line is thoroughly blown out. (8) The purging area should not be expanded too much, to avoid insufficient supply of the purging medium and low pressure, which could affect the effectiveness and quality of the purging process. (9) A dedicated person should be assigned to oversee the entire purging process, providing unified command and coordination; for the actual purging, one team should handle one area, and one person should be responsible for each pipeline. After the purging is completed, the purger themselves, the team, and the unit supervisor conduct inspections and acceptance checks on the quality of the purging at each level. (10) Accessories such as flanges, orifice plates, control valves, etc., that have not been installed before purging must be recorded and organized by a designated person. After purging is completed, install as required and record it for future reference. (11) Pipelines that have been partially purged with steam can be dried with an industrial blower after the purging is completed. 4. Precautions for steam purging (1) It is essential to drain condensate first before introducing steam. The principle of gradually increasing the steam flow—starting with a small amount to ensure proper circulation, followed by condensate drainage and line warming—must be adhered to. Prevent water hammer at all costs. In the event of water hammer, steam flow must be reduced or even stopped until the pipelines cease vibrating; only then can water be drained and steam reintroduced. (2) When purging with steam for the first time or suddenly increasing the steam flow, a dedicated person should be stationed at the discharge outlet to prevent burns from the steam. It is best to cover the outlet with metal sheeting to prevent dirt from splashing. (3) As the pipelines expand due to heating from steam purging, it is strictly prohibited to increase the flow rate immediately after introducing steam. This is to avoid sudden expansion of the pipelines caused by heat, which could lead to them pushing forward without enough time for compensation and resulting in buckling. It may also cause problems such as water hammer, detachment of pipe supports, deformation of the pipelines, fragmentation and falling off of insulation materials, tilting of pipe racks, cracking of welds, and separation of gaskets. During purging, it is necessary to keep an eye out for any of these issues and make records to facilitate verification and handling. (4) In principle, heat exchange equipment should not be included in steam purging. If the purging medium must pass through such equipment, its inlet piping must be thoroughly purged first. When the purge medium flows in one direction, the other side must be opened to vent, to prevent the heat exchanger from experiencing pressure buildup and leaks. When steam enters the heat exchange equipment, it must do so slowly, allowing for a warming-up process, in order to prevent sudden temperature rises from causing uneven thermal expansion of the heat exchanger and resulting in leaks. (5) When the pressure rating of the purged pipelines and equipment is lower than the pressure of the purging steam, safety valves shall be put into service, and temporary pressure gauges shall be installed. (6) After the steam purging is completed, the low-point drain and high-point vent of the system should be opened to prevent negative pressure from forming due to steam condensation, which could damage the equipment. 5. Quality requirements for purging (1) General provisions for pipeline purging and flushing a After the pipeline has passed the pressure test, the production unit shall organize the purging process; a purging plan must be prepared prior to purging. The cleaning method should be determined based on the requirements for using the pipeline, the working medium, and the degree of dirt inside the pipeline. For liquid or gas pipelines with a diameter of 600 mm or more, manual cleaning is used, while for liquid pipelines with a diameter of less than 600 mm, water flushing is employed ； For gas pipelines with a diameter of less than 600 mm, air purging is used for treatment ； Steam piping shall be steam-purged; non-thermal piping must not be steam-purged. For pipelines with special requirements, corresponding methods shall be adopted in accordance with the design specifications. c Pipelines that do not allow purging and flushing should be separated from pipelines that do permit such operations. d Before pipeline purging and flushing, orifice plates, check valves, throttle valves, control valves, safety valves, and instruments should not be installed. For valves and instruments that have already been installed, they must be removed or bypassed through alternate routes. The cleaning and flushing of pipes should be carried out sequentially for the main lines and branch lines, and the dirt expelled must not enter the pipes that have already been deemed satisfactory. f Before purging and flushing the pipes, it is necessary to check the stability of the pipe supports and hangers; if needed, they should be reinforced. The dirt removed through sweeping and flushing must not be discharged indiscriminately to avoid polluting the environment. h A no-entry zone should be established when cleaning and flushing pipes. Flammable materials should not be placed nearby during steam purging. After the j-pipe has been purged and flushed successfully and returned to its normal state, no other operations that could affect the cleanliness inside the pipe shall be carried out. During the reset of the k-pipe, it should be inspected jointly by the project owner and the construction unit. (2) General provisions for water flushing: a Clean water should be used for flushing pipes, and the chloride content in the water must not exceed 25 ppm when flushing austenitic stainless steel pipes. b When flushing the pipeline, the maximum flow rate should be used, with the minimum flow rate being no less than 1.5 m/s. The discharged water should be directed into drainage ditches or wells; the cross-sectional area of the discharge pipe must be at least 60% of the cross-sectional area of the pipe being flushed, and negative pressure must not occur during drainage. All the drainage branches of pipe d have been thoroughly flushed. The water flushing should be carried out continuously, and it is considered successful when the color and transparency of the water at the outlet are visually consistent with those of the water at the inlet. f When the pipeline is cleaned with water and not in use temporarily, the water should be drained completely and then dried with air as soon as possible. (3) General provisions for air purging: a Air purging should be carried out using the large compressors of the production facility, or by utilizing the large storage tanks in the facility to hold air for intermittent purging. The purge pressure must not exceed the design pressure of the containers and pipelines, and the flow rate must be at least 20 m/s. b When purging oil-free pipelines, the gas must be free of oil. c During the air purging process, once it is visually confirmed that there is no smoke or dust in the exhaust gas, a wooden target covered with a white cloth or painted white should be placed at the exhaust outlet for inspection; if no rust, dust, moisture, or other debris is present on the target within 5 minutes, it is considered acceptable. (4) General provisions for steam purging: The temporary pipelines installed for steam purging shall be erected in accordance with the technical requirements for steam pipes, and the installation quality shall comply with the provisions of this specification. b Steam pipes should be purged with high-flow steam, at a flow rate of not less than 30 m/s. c Before steam purging, the pipes should be warmed up first, water should be drained promptly, and the thermal displacement of the pipes should be checked. d The steam purging should be carried out in cycles following the sequence of heating-cooling-reheating. During purging, it should be done one by one, with alternating purging of each one. e The purging effect of the 3.5 MPa steam pipeline is checked using an aluminum target. The surface of the aluminum target should be smooth, with a width of 5–8% of the inner diameter of the exhaust port, and a length equal to the inner diameter of the exhaust port pipe. The aluminum target was replaced twice in a row for inspection. The target surface is considered qualified if there are no more than ten visually visible impact marks, and each mark is no larger than 1 mm. f For ordinary steam pipes or other pipes cleaned with steam, polished wooden boards can be placed at the steam outlet for inspection; the boards should be free of rust and dirt. g For pipes washed with water, unless otherwise specified, they are considered qualified if the color and transparency of the water at the outlet appear essentially the same as those at the inlet when inspected visually. For the quality inspection of purging in the desulfurization section and conversion section pipelines, it is also possible to conduct the inspection by placing a planed wooden board at the discharge outlet. (5) General provisions for chemical cleaning: a. For pipelines requiring chemical cleaning, the scope and quality requirements shall comply with the provisions specified in the design documents. b When chemically cleaning pipes, they must be isolated from unrelated equipment. c The formulation of the chemical cleaning solution must be validated and have been used in production facilities; it must have been proven to be effective and reliable through practical application. During chemical cleaning, operators should wear special protective clothing, as well as protective gear such as goggles and gas masks. e For pipelines that have passed chemical cleaning, when they cannot be put into operation promptly, they shall be sealed or protected by nitrogen purging. f The treatment and disposal of waste liquids after chemical cleaning must comply with environmental protection regulations. (6) General provisions for oil cleaning: a) Lubrication, sealing, and control oil pipelines should be cleaned with oil after the machinery and pipelines have been successfully pickled, and prior to the system’s trial operation. Stainless steel pipelines can be easily cleaned with oil after being blown clean with steam. b Oil cleaning should be carried out through oil circulation; during this process, the oil temperature should be raised and lowered repeatedly 2–3 times every 8 hours within the range of 40–70°C, and the filter element should be cleaned or replaced promptly. c Oil cleaning should use qualified oil suitable for the machinery to be cleaned; effective protective measures should be taken for the cleaned pipelines. Working oil with a certificate of conformity should be used before trial operation.

What was said on the 7th floor is great! On our end, the entire set of equipment has not been purged, and the storage tanks have not been purged either. During purging, instruments, flow meters, control valves, etc. must be removed. The pump’s inlet and outlet must be isolated! We don’t have any other requirements either!

I’ve learned it; I hadn’t been exposed to the on-site operating procedures before