June 21, 2024 Longchang Chemical

Chemical plant pre-commissioning, linkage commissioning safety operation points

I. Piping system pressure test

1、Piping system pressure test conditions
a. Safety valves have been blinded, rupture plates have been removed and blinded.

b. Expansion joints have been added with restraining devices.

c. Spring supports and hangers are locked.

d. When the test is conducted with water as the medium, the bearing capacity of the structure has been confirmed or accounted for

e. Pressure gauge has been calibrated and qualified


2, piping system pressure test should comply with the following provisions

a. To air and process media for testing, subject to the design unit, the production technology sector agreed to

b. Before the test to confirm that the test system has been effectively isolated from related systems

c. Hydraulic test, to clean fresh water as a test medium, when the system is connected to austenitic stainless steel equipment or piping, the chlorine content of water shall not exceed 0.0025%

d. The test temperature must be higher than the material’s brittle transition temperature

e. When the test in the cold season, there should be anti-freezing measures

f. Pipeline pressure test should be in line with the relevant national standards and norms required

g. After the end of the test, should be drained of water, gas and good reset work


II. Water flushing


a. Pressure test is qualified, the system machinery, instrumentation, valves and other protective measures have been taken, the temporary piping installation is completed, the flushing pump is running normally, the flushing pump inlet installation of the screen before the water rinse

b. Flushing work should not be carried out in the cold season, such as must have anti-freeze, anti-skid measures

c. When filling and draining, the piping system should be connected to the atmosphere.

d. In the previous process of piping and mechanical flushing before passing, flushing water shall not enter the next process

e. Flushing water shall be discharged into designated locations.

f. After flushing should ensure that all the drainage and exhaust piping is unobstructed


III. Instrumentation system commissioning


1, instrumentation system commissioning conditions

a. Instrument air station with normal operating conditions, instrumentation air piping system has been purged qualified

b. Control room air conditioning, uninterruptible power supply can be used normally

c. Transmitters, indicating and recording instruments, interlocking and alarm signaling switches, regulating valves, as well as disk-mounted, rack-mounted instrumentation, etc., has completed the single-unit tuning

d. Automatic control system regulator parameters have been preset, feed-forward control parameters, ratio values and a variety of calibration ratio bias system has been calculated and preset according to the relevant data

e. All kinds of analog signal generating devices, test instruments, standard sample gas, communication tools and so on have been prepared

f. All on-site instruments and control valves are in operation.


2, instrumentation system commissioning should comply with the following provisions

a. Detection and automatic control system in conjunction with mechanical testing should be simulated before debugging, that is, input signals at the transmitter, in the operating table or secondary instrumentation to check the instructions, control, alarm and other all functions

b. Interlocking and alarm systems should be simulated before the test with the machinery, that is, in the transmitter switch to input analog signals, check the logic of the correct and action, and adjusted until qualified

c. In the debugging and mechanical tuning instrumentation, instrumentation, electrical, process operators must work closely with each other

d. For the first trial or under load temporarily can not be put into use interlocking devices, the construction (production) unit agreed, can be temporarily removed, but should retain the alarm device

e. Before chemical feeding trial, should feed forward control, ratio control and control system with corrector, according to the load and the actual material composition, re-adjustment of parameters


IV. Electrical system commissioning


1、Electrical system commissioning conditions

a. The total substation of all the installation work and debugging projects related to the power supply department has checked, confirmed and completed the procedures for receiving electricity

b. Isolation switches, load switches, high-voltage circuit breakers, switchgear, transformers and other primary equipment has been carried out and qualified for the handover test

c. Relay protection and other secondary equipment has been tested and qualified

d. AC and DC operation power debugging qualified

e. UPS and other emergency power debugging qualified

f. With grounding resistance test records

g. With electrical equipment testing records

h. With interlocking protection test qualified records


2, the commissioning of electrical systems should comply with the following provisions

a. Power supply and distribution personnel must be licensed, strict implementation of the operating system

b. Transformers and distributors must be powered by the system before the relay protection devices, automatic reclosing devices, alarms and pre-phase system simulation test

c. The programmable logic controller protection device should be simulated interlocking and alarm parameters, should verify the correctness of the positive alarm value of its logic

e. Should be carried out in the accident power supply system of the trial and confirmation

f. Should be operated in accordance with the specified procedures for power outage and power supply

g. Acceptance of the electrical system should be carried out before power supply.


V. System replacement


1. Before the chemical plant is put into commissioning, it must be qualified with inert gas replacement and system replacement conditions:

a. Replacement flow charts that have been marked with air release points, analysis points and blind locations

b. Sampling analysts have been in place, analytical instruments, drugs have been prepared

c. Inert gas can meet the needs of the replacement work


2、System replacement conditions should comply with the following provisions:

a. Oxygen content in the inert gas shall not be higher than the safety standard.

b. Confirm the quantity, quality and installation parts of the blind are qualified.

c. Replacement should pay attention to the dead space in the system, if necessary, can be taken repeatedly to boost pressure, pressure relief method to replace the gas

d. When the piping system is connected to the gas cabinet, the gas cabinet should be repeatedly raised and lowered three times to replace the gas in the annular water seal.

e. Replacement work should be carried out continuously in the order of first main pipe and then branch pipe.

f. Analysts should pay attention to the wind direction and the height and direction of the air release pipe when taking samples to prevent poisoning.

g. The analyzing data should be qualified for three consecutive times, and be signed by the personnel in charge of production, technology and safety.

h. Replacement is completed, the inert gas pipeline and the system to take effective measures to isolate.

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