1. Drive safely
Check to make sure that water, electricity and steam (gas) meet the commencement requirements, and all kinds of raw materials must be fully supplied and qualified.
Check the opening and closing state of the valve and the drawings of the blind plate to ensure the smooth flow of the device, and all kinds of electromechanical equipment and electrical instruments should be in good condition.
Heat preservation, pressure maintenance and cleaning equipment should meet the requirements of start-up. If necessary, it should be replaced, cleaned and analyzed again to make it qualified.
Safety and fire control facilities are in good condition, communication is smooth, and the production device with great danger is started, and the fire control and medical and health departments should be notified to be present.
During start-up, it is necessary to strengthen the connection between related posts, strictly follow the steps in the start-up plan, and strictly abide by the requirements of temperature rise, pressure rise and fall, and load rise and fall range (rate).
Pay close attention to process changes and equipment operation during driving, handle abnormal phenomena in time, stop driving in case of emergency, and do not drive forcibly.
2. Safe parking
Normal parking must be carried out according to the steps in the parking plan, and the automatic parking interlock device used for emergency treatment shall not be used for normal parking.
The depressurization and cooling of the system must be carried out according to the required amplitude (rate) and the order of high pressure first and then low pressure.
For the equipment (container) that needs pressure maintenance and thermal insulation, the changes of pressure and temperature should be recorded in time after parking.
When large transmission equipment stops, the main engine must be stopped first, and then the auxiliary engine must be stopped.
Pay attention to the discharge and distribution of inflammable, explosive, toxic and other dangerous chemicals when the equipment (container) is depressurized to prevent accidents.
The pressure relief operation shall be carried out slowly and shall not be removed before the pressure is exhausted.
Replace the equipment with toxic, harmful, flammable and explosive gases.
Generally, nitrogen and steam are used for replacement, so nitrogen is preferred. Because the steam temperature is high, the tower should be cooled after replacement, so that the temperature in the equipment can be reduced to normal temperature.
Matters needing attention in chemical reaction in chemical process
1. Matters needing attention in oxidation reaction
If air or oxygen is used as oxidant in the oxidation process, the ratio of reaction materials should be strictly controlled outside the explosion range.
Before the air enters the reactor, there should be a purification device to eliminate dust, moisture, oil stains and impurities that can reduce the function of the catalyst or cause poisoning, so as to maintain the activity of the catalyst and reduce the possibility of fire and explosion.
In order to prevent the contactor from endangering the safety of personnel and equipment in case of explosion or fire, fire extinguishers should be installed in front of the reactor and in the pipeline.
In order to prevent the contactor from exploding, the contactor should be equipped with pressure relief devices (explosion-proof membrane and explosion-proof sheet), and automatic control and alarm interlocking devices should be adopted as far as possible.
2. Matters needing attention in nitration reaction
Nitration is an exothermic reaction, so the nitration process needs to be carried out under cooling conditions.
It must be noted that if the nitration reaction is slightly neglected, the stirring is stopped halfway, the cooling water is ineffective, the feeding speed is too fast, the temperature will rise sharply, and polynitro compounds will be generated, which may cause the danger of combustion and explosion.
Nitrating agents have a certain degree of oxidation, and commonly used nitrating agents such as concentrated nitric acid, nitric acid, concentrated sulfuric acid, fuming sulfuric acid and mixed acid all have strong oxidation, water absorption and corrosiveness.
Avoid contact with grease, organic matter, especially unsaturated organic matter during use, otherwise it will cause combustion.
When preparing nitrating agent, do not overheat or enter a small amount of water (to ensure that the equipment does not leak), otherwise it may cause combustion and explosion.
Most nitrated substances are flammable, such as benzene, toluene, chlorobenzene and naphthalene derivatives. These substances are not only flammable, but also toxic. In the process of use, we should pay attention to the implementation of corresponding safety precautions to avoid fire, explosion and poisoning accidents.
3. Matters needing attention in chlorination reaction
The raw materials used in the reaction process are mostly organic inflammables and strong oxidants, such as methane, ethane, benzene, toluene, ethanol and liquid chlorine. In the production process, the safe distance of the fire source should be strictly controlled, and the fire and explosion protection requirements of the factory building should be strictly observed.
Chlorinating agent commonly used in chlorination process is liquid chlorine or gaseous chlorine. Chlorine itself is very toxic (it belongs to the second grade and is very harmful). Generally, liquid chlorine must be vaporized in an evaporator before use.
Under normal circumstances, it is not allowed to use cylinders or tank trucks for storing chlorine as storage tanks to prevent chlorinated organic substances from flowing back into the cylinders or tank trucks and causing explosions. A chlorine buffer tank must be set in the middle.
Chlorine gas should be equipped with complete personal protective equipment, and a reliable accident emergency rescue plan should be formulated, and the safety measures in the plan must be implemented.
Chlorination reaction is an exothermic reaction, especially at higher temperature, the reaction is more intense. Chlorination reaction equipment must have a good cooling system, and the chlorine gas flow rate should be well controlled to avoid accidents caused by violent reaction and sudden temperature rise.
In addition, almost all chlorination reactions will produce hydrogen chloride gas. Therefore, the corrosion resistance of equipment and the recovery of hydrogen chloride gas are particularly worthy of attention during use.
Precautions for fire and explosion prevention
1. Fire and explosion protection settings
In the parts that are easy to cause fire and explosion, over-temperature and over-pressure detection instruments, alarm (sound and light) and safety interlock devices should be fully set.
Where combustible gas (steam) may leak and spread, combustible gas concentration detection and alarm shall be set, and the alarm signal value shall be set below 20% of the lower limit of gas explosion.
All inert gas and combustion-supporting gas pipelines connected with flammable and explosive devices should be equipped with facilities to prevent flammable and explosive substances from entering, but it is not appropriate to use one-way valves alone.
Automatic and manual emergency pressure relief and discharge treatment tanks shall be provided for the equipment with over-temperature and over-pressure caused by explosion and decomposition of reaction materials.
The outlet of combustible gas (steam) vent pipe shall be provided with a flame arrester, and a stop valve shall be provided at a place convenient for operation.
So as to cut off the gas source and put out the fire in case of fire at the vent pipe outlet. The lowest part of the exhaust pipe shall be equipped with a fire pipe joint.
2. The principle and practice of fire and explosion prevention.
Combustion must meet three conditions: combustible, combustion-supporting material and ignition source.
Combustibility control: prevent combustible gas, steam, dust and air from forming explosive mixture;
Eliminate the ignition source;
Isolation from air: remove oxygen and other combustion-supporting substances.
Matters needing attention in handling dangerous chemicals
Before loading and unloading dangerous chemicals, make preparations in advance, understand the nature of the goods, and check whether the loading and unloading tools are firm. If they are not strong, they should be replaced or repaired.
If the tool is contaminated by flammable materials, organic substances, acids, alkalis, etc. , must be cleaned before use.
Operators should wear appropriate protective equipment according to the hazardous characteristics of different materials, and pay more attention to toxic, corrosive and radioactive materials.
Protective equipment includes overalls, rubber aprons, rubber sleeves, rubber gloves, rubber boots, gas masks, gas masks, gauze masks, gauze gloves and goggles.
Handling dangerous chemicals should be handled with care to prevent collision, friction, collision and vibration.
When liquid iron drums are packed and stacked, it is not allowed to slide off quickly with a springboard. Old tires or other soft objects should be placed on the ground, next to the pile. When loading slowly, do not invert the items marked "Do not invert".
If the package is found to be leaking, it must be moved to a safe place for maintenance, otherwise the package should be replaced. Tools that may cause sparks should not be used for repair.
Dangerous chemicals are scattered on the ground, and the car has fallen, so it should be cleaned up in time. For inflammable and explosive articles, soft objects should be cleaned after soaking in water.
When loading and unloading toxic substances, the air circulation at the site must be maintained. If you find poisoning such as nausea and dizziness, you should immediately rest in fresh air, take off your work clothes and protective equipment, and clean the contaminated part of your skin.
When loading and unloading explosives, Class I inflammables and Class I oxidants, vehicles without explosion-proof devices such as iron unicycle and battery car (battery car without Mars control device) shall not be used.
Personnel involved in the operation shall not wear shoes with nails.
Before loading and unloading highly corrosive articles, check whether the bottom of the box has been corroded to prevent the bottom from falling off.
When carrying, it is forbidden to lift the shoulder bar, carry or hug with both hands. You can only pick, lift and lift the car. When stacking, do not turn upside down, tilt or vibrate, so as not to spill liquid.
Clear water, soda water or acetic acid should be available on site for emergency use.
Matters needing attention in storage tank operation in chemical plant
Enter the equipment to run, so that the materials will not enter without cutting off; Do not enter if the cleaning and replacement are unqualified; Do not enter the running lights that do not meet the requirements; Do not enter without a guardian; Please do not enter without emergency rescue backup measures.
Sampling and analysis shall be carried out 30 minutes before entering the storage tank. Only after the concentration and oxygen content of flammable, explosive, toxic and harmful substances are qualified can they enter the operation.
Strengthen the ventilation in the tank according to the specific situation; Intermittent operation should be taken in poorly ventilated environment.
When entering the tank to clean up toxic, harmful and corrosive residues, you must wear personal protective equipment and gas masks that meet the requirements.
After entering the equipment operation, sample and analyze the gas components every 2 hours; The guardian outside the tank should stick to his post and keep close contact with the outside world.
When the concentration of toxic gas is lower than the national specified value, it is forbidden to charge oxygen into the tank.
Electrical safety precautions
Electrical equipment must have a reliable grounding (zero) device.
Lightning protection and anti-static facilities must be in good condition and should be tested regularly every year.
Electrical work must go through professional training, pass the examination and show certificates, wear labor protection articles according to regulations, and use electrical tools that meet safety requirements.
Regardless of whether the high-voltage equipment is charged or not, the personnel on duty shall not move alone or work across the cover plate.
If it is necessary to remove obstacles, a guardian must be present, and the safe distance of the equipment without power failure must be met.
In thunderstorm weather, when it is necessary to patrol outdoor high-voltage equipment, the patrol personnel should wear insulating boots and should not be near lightning protection devices.
Before installing grounding wires on power-off lines and equipment, discharge and check the electricity. After confirming that there is no electricity, hang grounding wires on both sides of the work area.
Grounding wires should also be hung where it is possible to send electricity to the branch lines and the working area of the lines of the power outage equipment.
When hot work is carried out near live equipment, the distance between the flame and the live part is 10KV and below, 1.5m, and 3m above 10KV.
When replacing the fuse, the fuse should be selected in strict accordance with the regulations, and other metal wires should not be used at will.
Matters needing attention in using gas mask
(1) What are the safety precautions in the workshop? (2) Model essay on enterprise's work experience in production safety (three articles)? (3) Model essay (three articles) on the work experience of construction site safety production? (4) Model essay on the company's work experience in production safety (four articles)? (5) Model essay on community safety production (four articles)? (6) Summary and plan of safety work on the construction site. Precautionary measures and rectification opinions of enterprise safety production (two articles) (eight articles), brief self-inspection report of hospital safety production (three articles) (nine articles), demonstration report of enterprise safety production self-inspection report (three articles) (ten articles) and demonstration statement of enterprise safety production (five articles)
Before using gas masks, the concentration and oxygen content of toxic gases in the working environment must be analyzed and detected.
The oxygen content in the environment where gas masks are used should be greater than 18%, and the toxic gas content should be less than 2%. When one of them does not meet the requirements, it is forbidden to use the filter gas mask.
Pay attention to the scope of use and effective protection time of various poison cans.
If you feel uncomfortable during use, you can't take off the gas mask and leave the poisoned area immediately.
It is forbidden to use filter gas masks in closed containers, pipelines and oxygen-deficient environments. ;