Hottest auxiliary steam purging measures

Auxiliary steam purging measures

1.1 relevant drawings of Zhejiang Electric Power Design Institute

1.2 code for startup and completion acceptance of capital construction projects of thermal power plants (1996 edition)

1.3 regulations for startup and commissioning of thermal power projects

1.4 code for construction and acceptance of electric power construction (pipeline)

2 Purging steam source and steam parameters

the auxiliary steam purging steam source of Zhejiang Datang Wushashan Power Plant Phase I unit is supplied by the start-up boiler, and the steam supply parameter of the start-up boiler is 1.27mpa (g)/350 ℃

3. Safety precautions

the safety of personnel and equipment must be ensured during the purging process. In case of the following situations, the purging should be stopped immediately:

3.1 the steam quality is too poor, such as the superheat of steam source temperature is lower than 50 ℃, and the pressure is lower than 0.8MPa

3.2 there is steam leakage in the pipeline

3.3 injury at the steam nozzle

3.4 the pipeline is not drained smoothly or the pipeline is not warm enough, and there is violent vibration during purging. Pay close attention to the real needs of customers

3.5 there is serious steam leakage between pipelines, and it is impossible to isolate

4. Quality inspection

for auxiliary steam purging, we should mainly observe whether the exhaust color of the exhaust port is qualified, and whether the purging is completed should be confirmed by Party A, electric power Research Institute, installation unit, supervisors and other parties

Part II: purging scheme of auxiliary steam system of steam turbine island

1. Purging scope

the purging scope of measures in this part is the steam pipe at the side of auxiliary steam turbine, including: steam pipe from Startup boiler, auxiliary steam main pipe, auxiliary steam main pipe to deaerator heating steam pipe, auxiliary steam main pipe to deaerator pre heating steam pipe, auxiliary steam main pipe to a and B small steam turbine commissioning steam pipe, The four section extraction pipe to the auxiliary steam main pipe, the reheat cold section to the auxiliary steam main pipe, the steam pipe for the shaft seal of the main engine and feed pump turbine (including the main steam, cold reheat and auxiliary steam supply shaft seal pipes), the shaft seal overflow pipe, the auxiliary steam to the domestic water heat exchanger pipe, etc

2. Preparation and installation of temporary facilities

preparation of purging system

2.1 after the installation of auxiliary steam system pipes and valves, all electric valves in the auxiliary steam system are driven normally, and all manual isolation valves are opened and closed flexibly and tightly

2.2 after the relevant thermometer and pressure gauge in the system are calibrated and installed, the primary valve of the pressure transmitter should be closed

2.3 if there is a pipe section in the purging system that has not been insulated, inflammables should be removed. Prepare enough fire-fighting equipment, and assign special personnel to be responsible for fire fighting and warning of steam exhaust. No one is allowed to enter the steam exhaust area

2.4 the relevant valves of the purging system shall be numbered and tagged according to the system diagram. The valves to be operated shall be opened and closed once, and the isolation door shall be tightly closed

2.5 participate in the staff, clarify the division of labor and unified command

2.6 sufficient communication and lighting equipment should be prepared on site

installation of temporary system

2.7 the safety valve of auxiliary steam system is verified to be qualified and installed, including the safety valve of the pipeline from start-up boiler to unit 1, the safety valve of auxiliary steam main pipe, etc

2.8 remove all check valve cores in the auxiliary steam system. It includes: the auxiliary steam header lambrets uses the polymer Proplast of porous material polyvinylidene fluoride fluorocarbon polymer and carbon fiber as the check valve of the steam pipe from the artificial cornea tube to the deaerator heating, the check valve of the steam pipe from the auxiliary steam header to the commissioning of the small steam turbine, the check valve of the auxiliary steam header to the shaft seal steam pipe, the check valve of the steam inlet pipe from the fourth section extraction to the auxiliary steam header, the check valve of the steam inlet pipe from the reheat cold section to the auxiliary steam header Check valve from auxiliary steam main pipe to pre warming port of deaerator, etc

2.9 all regulating valve cores on the auxiliary steam system should be removed. If they cannot be removed, the whole set of regulating valves should be removed and temporary pipes should be added. The diameter of the temporary pipes should be the same as that of the original pipes. Including: auxiliary steam header to deaerator heating steam regulating valve, reheat cold section to auxiliary steam header regulating valve, auxiliary steam supply shaft seal steam regulating valve, main steam supply shaft seal steam regulating valve, reheat cold section shaft seal steam regulating valve, shaft seal overflow regulating valve, etc

2.10 throttling devices or flow measuring devices on the pipelines of auxiliary steam system and shaft seal system should be removed before purging and restored after purging is completed and qualified

2.11 if filters are installed on the pipelines of auxiliary steam system and shaft seal system, they should be removed before purging and restored after the auxiliary steam system is purged

2.12 all desuperheating water pipelines to the auxiliary steam system should be disconnected and blocked before entering the steam side pipeline. The desuperheating device should be removed and connected with temporary pipes of the same diameter

2.13 at this time, all steam pipes with punch pressing depth (mm) are connected to the outside of the main power house to discharge the atmosphere. All pipeline drainage should be smooth and temporarily discharged to the condensate pump pit. The drainage header is disconnected before entering the drainage flash tank, and then connected to the temporary pipeline to discharge outside the plant. Each exhaust outlet shall be reinforced, and the exhaust direction shall not affect the safety of equipment and personnel. Special personnel shall be assigned to monitor it. No person is allowed to enter the exhaust area

2.14 before purging, the installation unit should first clean the metal container of the auxiliary steam header and pass the inspection of all parties

2.15 the pipe from reheated cold section steam to auxiliary steam header is disconnected at the root near the cold reheat pipe, the cold reheat side is blocked, and the auxiliary steam side is connected Φ 219 temporary steam exhaust pipe to the outside of the plant

2.16 the root of steam seal inlet pipe of main engine and small turbine is connected with temporary pipe and steam seal steam return pipe, and the diameter of temporary pipe is not less than the diameter of steam inlet branch pipe. The steam seal steam return pipe is disconnected at the steam seal heater and connected to the temporary steam exhaust pipe outside the plant

2.17 the shaft seal overflow pipe is disconnected at the condenser, connected to the temporary pipe and discharged outside the plant

2.18 the inlet pipe of small steam turbine is disconnected in front of the main throttle valve of small steam turbine and connected to Φ 350 temporary steam exhaust pipe is blooming everywhere outside the plant

2.19 the steam inlet pipes on both sides of the deaerator are disconnected at the inlet and connected to Φ 508 temporary steam exhaust pipe to the outside of the plant

2.20 the pre heating steam pipe of deaerator is disconnected at the inlet and connected to Φ 273 temporary steam exhaust pipe to the outside of the plant

2.21 the back of the four stage extraction check valve is disconnected, and the side close to the extraction port is blocked, and the other side is connected to the temporary exhaust pipe outside the plant

2.22 the main steam to shaft seal steam pipe is disconnected near the root of the main steam pipe and connected to the temporary pipe outside the plant

2.23 the cold reheat to shaft seal steam pipe is disconnected near the root of the cold reheat steam pipe and connected to the temporary pipe outside the plant

2.24 the pipeline from the auxiliary steam to the domestic water heat exchanger is disconnected before entering the domestic water heat exchanger, and the temporary steam exhaust pipe is connected to the outside of the plant. Remove the temperature control valve and reinstall it after purging

2.25 the auxiliary steam main pipe to the stator cooling water heating steam pipe is disconnected before entering the heater, connected to the temporary pipe and discharged from the plant