Request for flushing and pressure testing plan for demineralized water pipelines

Rinsing with deionized water should work better, right! The solubility of desalinated water is higher than that of ordinary water, right?

There is no desalinated water plan; there is a boiler water pressure plan. I. Project Overview: This project involves the hydraulic testing of three 75T/h boiler units. The scope of the work includes the steam drum, heat transfer tubes (water wall tubes, header pipes, top connection pipes, downcomer pipes), superheater, economizer, and their associated headers. The working pressure of the steam drum is 4.22 Mpa; the testing pressure is 1.25 times this value, namely 5.275 Mpa. Approximately 60 T of water is required for the testing, and the ambient temperature is below 0°C. II. Basis for Preparation 1. \"Installation Instructions for 75T/h Boilers Provided by XXX Boiler Factory\" 2. \"Technical Specifications for Power Generation Plant Construction and Acceptance – Boiler Units\", DL/T5047-95 3. \"Technical Specifications for Power Generation Plant Construction and Acceptance – Boiler Chemistry\", DL/J58-81 4. Boiler drawings provided by XXX Boiler Factory III. Conditions to be met prior to hydrostatic testing a) The pipes, pipe components, and valves within the boiler’s pressure testing range have been constructed in accordance with the drawings, meeting the requirements of the design and relevant specifications ； b) The temporary pipes and exhaust pipes for the boiler pressure testing have been installed and are connected to the pressure testing pump ； c) The internals of the drum have been inspected and meet the requirements of the drawings and specifications ； d) The boiler furnace wall attachments, the corner-type coal powder burner mounts, the connections for hydraulic slag removal and the water wall, as well as the expansion indicators, have all been welded ； e) The interior of the tank and drum has been inspected and found to be clean and in compliance with requirements; the manhole cover on the drum has had new gaskets installed, and it has been checked to be properly tightened ； f) The hangers have been properly secured, with even stress distribution across all of them ； g) The pipeline has completed non-destructive testing in accordance with the specification requirements ； h) Welding of the pipe fittings has been completed ； i) Valves have been installed on the spare ports on the drum as well as on other instrument ports, and the safety valves have been isolated using blind flanges ； j) The water for pressure testing has been arranged; a solution has been found for discharging the water after testing, and the drainage pipes have been installed ； k) The pressure gauge used for pressure testing has been calibrated and is within its weekly inspection period; the full-scale value of the gauge should be 1.5 to 2 times the pressure to be tested, with an accuracy of not less than grade 1.5. Moreover, the temporary pipelines in front of the pressure testing pump and the steam collection box have been installed ； l) The civil engineering plant has been sealed off; heating has been installed in the boiler plant, and its ambient temperature is now above 5℃ ； m) The boiler footings have been grouted, and their strength has reached 70% of the design strength ； n) Complete spectral analysis data for alloy steel pipes ； o) The pipes that require heat treatment have been heat-treated ； p) The boiler water level gauge has been installed as required ； q) The documents were submitted for inspection prior to the hydrostatic test ； r) Notify the Yulin City Quality and Technical Supervision Bureau to conduct on-site inspections and participate in the hydrostatic test. IV. Preparations before the hydrostatic test: Taking into account the ambient temperature at the location where the testing will take place and the actual conditions on site, we have prepared the following three testing plans: A: This plan involves completely enclosing the boiler room, with heating provided around the boiler at the 0m and 7m levels of the workshop. a) Based on the dimensions of the boiler used for testing, a simple boiler room will be constructed to the east of the M-axis, between the 2/3 axis and the 3/3 axis in the boiler room ； (Detailed production process see attached diagram) ； b) Pour a plain concrete foundation according to the boiler size, and embed steel plates during pouring ； c) Channel steel [14a] is used as supports in the boiler room; the walls are made of two layers of profiled sheets with rock wool in between ； d) After the boiler room, boilers, and pumps have been installed, pipes and radiators shall be arranged at the 0m and 7m levels of the boiler room. If steel tube radiators are used, the heat dissipation area required is 1000 m2; with steel tubes of diameter φ159*4, the total length is 2000 m. If steel column radiators are used, the heat dissipation area required is 1500 m2, with 22 radiators per set and a total of 120 sets. The boiler is a 2-ton hot water boiler, with an outlet temperature of 90°C and an inlet temperature of 70°C℃ ； e) Between the installation axes of the boilers used for pressure testing, a high-level water tank (with a capacity of 5 m3) for auxiliary equipment in the boiler room is placed at an elevation of 13 m; pipes are used to connect this tank to the boilers to supply water to them ； f) Install a support using channel steel [18] for the drain tank of the auxiliary equipment in the boiler room; then install an ash flushing pump (Q=40m3, H=70m) on top of the base of the drain pump for the auxiliary equipment in the boiler room. Since the bases of the two pumps are different, a support made of channel steel [14a] is required ； g) To maintain the boiler feedwater temperature, it is heated at the bottom of the drain tank using four carbon fires, or with electric heaters ； h) After the drain tank and the ash flushing pump have been installed, connect the drain tank to the ash flushing pump using pipes; connect the outlet of the ash flushing pump to the boiler feed water pipe via pipes. Install thermometers on the pipes of the tank and the outlet of the ash flushing pump ； i) Connect the drain tank inlet pipe to the outdoors ； j) Connect the pressure testing pump to the ash flushing pump with pipes ； k) Connect the regular sewage main pipe to the sewage well using temporary pipes with a diameter of φ89*4; the water conveyance pipes must be insulated with rock wool sleeves. B: Adopt a fully enclosed boiler room, with carbon fires arranged around the boiler as well as above and below it. 1. Six carbon fire burners are installed on top of the hydraulic slag removal system at the bottom of the furnace chamber ； 2. Two coke furnaces are arranged on each side of the 12m platform of the boiler, and two coke furnaces are arranged on each side of the 18m platform of the boiler ； 3. Install 2 carbon furnaces at the bottom of the downpipe under the front wall of the boiler ； 4. Install 2 carbon furnaces at the top of the rear wall of the boiler ； 5. One coke furnace is arranged around each of the upper and lower economizers ； 6. One coke furnace is installed on each side of the primary superheater ； 7. Install 2 coke furnaces on the guard plate in front of the primary superheater ； 8. Install a thermometer at each appropriate location where coke fire is arranged ； 9. The water supply method is the same as in Plan 1. C. Use steam at 0.4–0.5 Mpa to heat the water in the boiler. Steam is delivered from the bottom drain main of the boiler header. 1. Steam coming from the outside enters via pipes that are connected to the bottom drain main of the header, and another pipe is used to convey the steam into the drain tank ； 2. Four thermometers each are installed around the boiler, at the 0m level, at the 7m level, and on the top ； 3. Steam should be continuously supplied to the boiler during the irrigation process ； 4. Once the tank is filled with water and testing for pressure is to be carried out, close the valve that supplies steam ； 5. After the pressure testing is complete, once all the water has been drained, continue to feed steam into the boiler until the ambient temperature is above 5°C ； 6. The water supply method is the same as in Plan 1. Note: When the first and third options are adopted, the second option should also be prepared as a contingency plan. V. Requirements for hydrostatic testing: a) The water used for hydrostatic testing should be deionized or softened water to which a certain amount of ammonia or hydrazine has been added. When it is difficult to use softened or deionized water, clear water to which a certain amount of ammonia or hydrazine has been added can also be used. The quality standards for this water must meet the following requirements: dissolved oxygen < 50 micrograms/liter, iron < 100 micrograms/liter, hardness < 10 milliequivalents/liter, and pH value between 8.5 and 9.2 ； b) There are two pressure gauges used for the hydrostatic test: one is installed on the steam collection box, and the other is installed at the outlet of the testing pump; the reading shall be based on the pressure gauge on the steam collection box ； c) The ambient temperature during the hydrostatic test must always remain above 5°C, and a dedicated person shall be responsible for monitoring the boilers and furnaces used for the testing. VI. Steps for hydrostatic testing: a) The valve of the drain pipe should be closed, and the vent valve on the steam collection box should be opened ； b) Transport the qualified softened water to the construction site using fire trucks, connect the fire hoses to the inlet pipes of the water tank. Once the water temperature in the tank reaches 35°C, start the slag flushing pump to feed water into the steam drum through the main feed pipe and economizer. During the water transfer process, a dedicated person should monitor the water level gauge; meanwhile, the valves for the main feed pipes of boilers No. 2 and No. 3 must remain closed. When the water level gauge indicates zero, stop feeding water and close the valve for the main feed pipe of Boiler No. 1 ； c) Open the valve of the superheater backwash pipeline, and continue to feed water into the boiler. When the water level rises to +100 mm, close the valve of the superheater backwash pipeline and open the valve of the boiler’s main feed pipe to keep feeding water until the entire boiler system is filled with water ； d) After filling it with water, first check the entire system for any leaks. If small leaks are found at the welds, they can be repaired on-site. In the case of large leaks, the water must be drained first before repairs can be carried out. If no leaks are detected, the pressure can be increased, with an increase rate of no more than 0.3 Mpa/min. Once the test pressure reaches 0.5275, a preliminary inspection of the entire system should be conducted ； If no leaks are detected, it can be directly increased to 4.22 Mpa to check for water leakage and any abnormalities ； If not, increase the pressure further to 5.275 Mpa for testing; maintain this pressure for 5 minutes, then reduce it to the operating pressure of 4.22 Mpa to conduct a thorough inspection. The pressure must remain constant during the inspection. If there are no signs of cracking, deformation, or leakage, the water pressure is considered acceptable ； e) During the pressure testing process, when the pressure reaches the operating pressure of 4.22 Mpa, close the gauge valve and remove the water level gauge to prevent damage ； f) During the pressure testing, the readings should be based on the pressure gauge on the steam collector ； g) During the pressure testing process, a dedicated person should monitor the pressure gauge to ensure that the pressure does not exceed the allowable level; if overpressure occurs, the boiler’s emergency pressure relief valve must be opened immediately to release the pressure ； h) After the hydrostatic test is successful, first open the drain valve on the steam collection box, then open the sewage drain valve on the lower collection box, and drain water promptly. The drainage speed should be slow to prevent a negative pressure from forming in the system ； i) After the water has been partially drained, remove the temporary pipes and install the instrumentation components ； j) After the pressure test is successful, proper records of the test must be kept, and these records should be signed for confirmation by the supervision company, the Quality and Technical Supervision Bureau, and the representative of the client. VII. Corrosion protection for the boiler system: Since the boiler cannot be subjected to alkali treatment promptly after pressure testing, corrosion protection is necessary. The methods for corrosion protection are as follows: a) For short-term shutdowns (i.e., between 15 days and 30 days), ammonia or hydrazine solutions can be used for protection; the concentration of ammonia is generally 500 mg/L, while the concentration of hydrazine is usually 150–200 mg/L, with a pH value greater than 10. b) For long-term shutdowns (i.e., more than 30 days), nitrogen filling or the use of gas-phase corrosion inhibitors can be employed. The purity of the nitrogen used should be greater than 98%, and the pressure of nitrogen in the system to be protected should be maintained at 0.02–0.05 Mpa. VIII. Safety Precautions a) A no-entry zone should be established during the pressure testing process, and unauthorized personnel are not allowed to enter ； b) During and after the pressure testing, a dedicated person should be assigned to monitor the thermometer, the furnace, or the boiler used for testing, ensuring that the system remains above 5°C until the outside temperature reaches this level ； c) During the pressure testing process, those involved must be familiar with the testing plan and must not leave their posts without permission ； d) Pressure testing personnel must communicate using signals, and key personnel should be equipped with communication devices. Do not allow the system to exceed pressure limits ； e) If severe leaks occur during the pressure testing, it is not permissible to attempt repairs while under pressure; the water must be drained first before restarting the pressure testing ； f) During the pressure testing process, it is necessary to closely monitor the testing system for any signs of cracking, deformation, or abnormalities; if such issues are detected, the pressure increase must be stopped immediately ； g) During the water discharge process, the top vent must be opened to prevent negative pressure from forming, and the discharge speed should be slow ； h) During the movement of the boiler installation, pressure testing personnel must be careful to avoid burns from hot surfaces ； i) During and after the pressure testing process, tools and metal objects must not be thrown from heights to prevent injury to people or the toppling of the coke fire, which could lead to a fire. IX. Members of the pressure testing team
Project owner: Omitted
Supervising agency: Omitted
Construction contractor: Omitted

X. List of equipment for pressure testing
Serial No. Name of Equipment Specifications Unit Quantity Remarks
1 Electric pressure testing pump, 10Mpa Set 1 For shared use
2 Thermometer Piece 15
3 Pressure gauge, 10Mpa Piece 2
4 Pressure gauge, 0.7 Mpa Piece 1
5 Centrifugal pump, Q=40m3, H=70m Set 1
6 Seamless steel pipe, φ89*4 mm Meter 250
7 Seamless steel pipe, φ108*4 mm Meter 60 For shared use
8 H-shaped steel, H300 Ton 1
9 Pressure gauge adapter Piece 2
10 Channel steel [18a] Ton 1.8
11 Coke furnace Piece 4
12 Electric heater 1
13 Boiler for pressure testing, 2t hot water boiler Set 1 First option
14 Coal Ton 60
15 Channel steel [14a] Ton 1.5
16 Channel steel [10] Ton 0.5 First option
17 Steel plate, δ=10 mm Ton 0.1
18 Corrugated sheet m2 40
19 Hook bolts, φ6 Piece 150
20 Rock wool m2 200
21 Rock wool casing, DN150, δ=50 mm m2 150
22 Rock wool casing, DN80, δ=50 mm m2 100
23 Steel column radiator Piece 2640
24 Seamless steel pipe, φ159*4 mm Meter 2000
25 Globe valve Piece 26
27 Steel plate, δ=4 mm Ton 0.5
28 Coke furnace Piece 30 Second option
29 Coke Ton 70
30 Seamless steel pipe, φ89*4 mm Meter 1500 Third option
31 Channel steel [10] Ton 1