This paper focuses on the safety technical measures of the reactor in the unit system during operation. An atmospheric pressure reactor and a condenser with liquid material transport and exothermic reaction are used as the simplest operation unit to analyze the dangerous and harmful factors that may be generated, to develop corresponding safety precautions, and to implement emergency response plans.
I. Analysis of major dangerous and harmful factors:
1. Feeding error: If the feeding speed is too fast, the feeding ratio is out of control or the feeding sequence is wrong, it may produce a rapid exothermic reaction. If the cooling cannot be synchronized, heat accumulation will occur, causing the material to be partially decomposed by heat, forming a rapid reaction of the material. And a large number of hazardous gas explosions occurred.
2. Pipeline leakage: When feeding, for the atmospheric pressure reaction, if the venting pipe is not opened, when the liquid material is transported into the kettle by the pump at this time, the positive pressure is easily formed in the kettle, which may cause the material pipe joint to crack, and the material is outside. A burn accident that causes personal injury. When unloading, if the material in the kettle is unloaded without cooling to the specified temperature (generally required to be 50 ° C or less), the material of higher temperature is easily deteriorated and it is easy to cause the material to splash and burn the operator.
3. The temperature rises too fast: the material in the kettle is too fast, the cooling rate is low, and the condensation effect is poor, which may cause the material to boil, form a vapor-liquid mixture, generate pressure, and weak from the venting tube and the vapor phase tube. The pressure relief system such as the link and safety valve and rupture disc is used to carry out pressure relief and punching. If the punching material cannot reach the suburban fruit with rapid pressure relief, it may cause an explosion accident in the kettle.
4. Maintenance of hot fire: If the welding and gas cutting maintenance work is carried out without taking effective precautions during the material reaction process in the kettle, or the bolts and irons are hit and beat, a spark is generated, and once the flammable and explosive leakage is encountered, Materials can cause fire and explosion accidents.
Second, safety technical measures:
1. Heating control measures: For the heating system of the material with the reaction temperature below 100 °C, steam and hot water can be used for sectional heating. When the material is not deteriorated due to local overheating, the steam is heated to 60 °C at medium speed. Left and right, in order to improve production efficiency, and then use 100 ° C boiling water to heat transfer, slowly warmed to the temperature specified by the process and keep the reaction. Such sectional heating can prevent the local high temperature from being thermally decomposed or violently vaporized while improving the production efficiency, thereby forming a vapor-liquid mixture and exploding the mixture, and can also improve the yield and reduce the consumption cost for the material balance reaction.
2, interlocking cooling measures: For the exothermic reaction, the initial stage of the reaction needs to be heated, but the reaction process will be exothermic, so the excess heat must be transferred quickly and efficiently. The reactor cooling system used normally is mainly jacket cooling and coil cooling, and the coolant used is mainly circulating water and freezing liquid. The chilled liquid cools quickly but at a high cost. In the case of abnormal reaction during the production process, especially when the temperature and pressure rise sharply, the operator will quickly evacuate the operation site for his own personal safety, and the heating source cannot be effectively cut off, and the cooling system cannot be effectively turned on. For this purpose, an emergency opening and cooling interlocking system should be provided at a remote location outside the operating position. It is better to be close to the steam valve of the steam sub-cylinder of the workshop. When the steam valve is closed and the stirring power supply is turned off, the cooling interlocking system is turned on, and the measures of heat-breaking, power-off, stop stirring, rapid cooling and cooling are implemented to control the accident in the initial stage. Prevent further expansion of accidents.
3. Chain venting measures: In order to prevent the material in the kettle from being out of pressure and generating gas pressure, the pressure can be relieved in time. For atmospheric pressure reaction equipment, emergency pressure relief facilities should be installed according to the specific conditions of the reaction. Safety valves should be installed at the top of the kettle, and rupture discs should be installed for processes that may have a more violent reaction. The outlet of the connecting pipe of the rupture disc must extend to the outdoor safe place or the exhaust pipe, and cannot directly point to the road or the operating platform to prevent the material from splashing and injuring people. The drip acceleration should be strictly controlled in the case of a dropping reaction process.
4. Anti-static measures for confined conveying: For the material conveying pipeline system, steel pipes or plastic pipes should be selected according to the material characteristics (the plastic pipes are not allowed in principle, except in special cases). Regardless of the type of pipe, flanges or bolted connections are used to prevent leakage of material. Do not use a rubber sleeve to connect the plastic tube to transport organic solvents. For the flange part of the steel pipe, make a static crossover. If there are six bolts (including six) on the pair of flanges, do not need static crossover. Four or less (including four) must be electrostatically bridged (for symmetry). There are no five normal, if there are five, you need to cross.) A 4 mm square copper core wire is used for the electrostatic jumper. Plastic pipes should be electrostatically connected when transporting organic solvents or other materials that are prone to static electricity. The connection method is to set fine copper coins inside the pipes. The specific method is mainly to weld a small steel nail at the outlet of the metal pipe and moderately tilt it into the pipe. The fine copper money must be wrapped around the small steel nail and fastened, pass through the plastic pipe, and the other port comes out and is fastened at the pipe. . Only in this way can the electrostatic flow be generated and the static electricity can be transferred to the grounding system in time.
5. Labor protection measures: installing blowers or exhaust fans in the operation positions can not only protect the health of the operators, but also reduce the concentration of flammable gas in the operating positions and prevent the explosion limit from reaching the explosion limit. In order to prevent the gas material in the kettle material from leaking under pressure, the operator should be installed in the operation room. Introduce outdoor high-altitude fresh air to the operating room, so that the operating room is in a slightly positive pressure state. Equipment that emits toxic and harmful gases should be placed on the downwind side of the local dominant wind direction for gas diffusion or evacuation, and it is also convenient for operators to reduce gas pollution damage.
6. Maintenance fire safety measures: The goal of the fire safety management technical measures is two guarantees: one is to ensure that there is no flammable material inside the hot fire equipment pipeline, and the other is to ensure that there is no combustible material around the hot fire equipment pipeline. To achieve two guarantees, we must correctly understand the importance of hot fire management, enhance safety awareness, and implement safety technical measures such as cutting, isolation, replacement, cleaning, ventilation, etc., and perform preliminary examination, review, approval, supervision, and cleanup according to procedures. Safety management measures such as acceptance.
7. Other safety measures: The mechanical equipment must be effectively grounded, and the grounding resistance should not be greater than 10Ω; the motor must have the connection of the neutral line; the transmission part of the reducer must have a protective cover; the operating table must be stable and cannot be shaken, there must be no opening; the protective railing must be Above 1.05 meters, and the upper and lower spacing of the railings should not be greater than 0.35 meters; the height of the equipment off the ground should not be able to collide with the human head. For the batch feeding in the middle of the operation process, it is better to install the valve and the funnel on the manhole cover; the venting pipe of the condenser is applied to the outdoor or the exhaust pipe port, and cannot directly align with the channel and the operator's place; Conditions should also be set up for emergency evacuation channels and full-process monitoring and alarm facilities; nitrogen protection measures should be taken during the parking process. Equipment that may cause runaway reactions for power outages and water cuts should have a dual circuit dual water source system.
Third, the emergency response plan for actual incidents
1. When the production temperature and pressure rise rapidly, it is necessary to quickly close all material inlet valves; stop stirring immediately; quickly close the steam (or hot water) heating valve, open the cooling water (or chilled water) cooling valve; quickly open the vent valve; When there is no venting valve and the temperature and pressure are still uncontrollable, the material discharge valve at the bottom of the equipment is quickly opened. When the above treatment has no effect, and the bottom discharge valve can not be completed in a short time, the personnel are quickly notified to evacuate the site.
2. When there is a large amount of toxic and hazardous substances, immediately notify the surrounding personnel to quickly evacuate the site; quickly wear a positive-pressure respirator to close (or tightly) toxic and harmful leaking valves; promptly notify the valve when the toxic and hazardous materials cannot be closed. The wind direction (or surrounding) units and personnel are sprinkled or prepared for prevention, and the treatment agent is sprayed according to the material characteristics for absorption and dilution. Finally, the spill is contained and properly treated.
3. When there is a large amount of flammable and explosive materials, you should quickly wear a positive pressure respirator to close (or tightly) flammable and explosive leaking valves; and quickly notify the surrounding (especially the downwind direction) when the flammable and explosive leaking valve cannot be closed. Personnel stop the production and operation of open flames, sparks, and quickly stop other production or operations around them, and when possible, move flammable and explosive spills to safe areas. In the case that the gas leakage has been burned, it is not rushed to close the valve. Care should be taken to prevent the tempering and the gas concentration from reaching the explosion limit and causing the explosion;
4. When personnel are injured, the cause of poisoning should be immediately identified and treated effectively; when poisoning is caused by inhalation, the poisoned person should be quickly moved to the fresh air in the upwind direction. When the poisoning is serious, it will be sent to the hospital for emergency treatment; when poisoning is caused by ingestion, drink plenty of warm water and induce vomiting. Or detoxify the milk or egg white, or take other substances to vent; when the skin is poisoned, immediately remove the contaminated clothing and rinse with plenty of running water. Seek medical treatment; when the poisoned person stops breathing, he or she will quickly perform artificial respiration; the poisoned person's heart stops beating and quickly presses the heart to take off; when the body's skin is burned in a large area, immediately wash the burned surface with a large amount of water, and rinse time. In about fifteen minutes, at the same time, be careful not to suffer from cold and frost, and replace the uncontaminated clothing and send it to the hospital for medical treatment.
The reactor is the most versatile equipment for fine chemical production enterprises, and it is also the most typical equipment in the unit system. It is the focus of safety production supervision. Only manage each reactor, safety production of each unit system, take corresponding safety interlocking measures, implement human error warning interlocking devices, realize the intrinsic safety of equipment, strictly implement the process operation rules and safety production operation specifications. It can ensure the stable operation of the entire production system, so that production must be safe and safe to ensure production.
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