Emergency Plan for Accidents in Distillation Operations

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This post was last edited by wawjia on 2010-11-23 at 12:13. Methanol molecular formula: CH3OH; molecular weight: 32.04. Methanol is a corrosive gas； Relative density (water=1) ； 0.792g/l; melting point: -97.5 degrees ； Boiling point: 64.5 degrees ； Heat of combustion > 27 kJ/mol ； Soluble in water ； It is miscible with various organic solvents such as alcohols and ethers. Flammable ； Its vapor forms an explosive mixture with air, and can cause combustion and explosion when exposed to an open flame. Its vapor is heavier than air, allowing it to spread over considerable distances at lower levels. In order to enable timely and effective emergency rescue in the event of a production safety accident, to facilitate early prevention as well as rapid emergency response once such an accident occurs, thereby reducing casualties and property losses, this plan is formulated in accordance with **relevant laws and regulations as well as guidelines set by higher authorities. I. Scope of emergency rescue: This plan is applicable to the distillation section of the methanol plant at Tengzhou Shenglong Company, in the event of major production accidents such as fires and explosions. II. Emergency Rescue Command Center and Its Responsibilities: An accident emergency rescue command center is established, with the command center located in the company’s production control room. The company manager serves as the chief commander, the deputy manager in charge of safety production acts as the deputy chief commander, other relevant leaders serve as commanders, and members from the relevant departments and the methanol workshop make up the team. 1. The company manager is the ultimate commander in handling disaster incidents; with the assistance of the company’s chief engineer and the head of the fire and rescue team, he formulates operational plans for rescuing those in danger and dealing with such disasters. In the absence of the chief commander, the deputy chief commander exercises the powers of the chief commander. 2. The chief engineer, under the leadership of the company manager, organizes the formulation of combat plans for rescuing people in distress and dealing with accidents. 3. The respective deputy managers are responsible, in accordance with the plans for rescuing those in distress and dealing with accidents, for organizing the workers needed to handle the accident and for promptly mobilizing the equipment and materials required for disaster relief. 4. The fire captain is responsible for the specific operations of the fire team, providing overall command over firefighting and rescue efforts. In accordance with the tasks outlined in the combat plan for rescuing people in distress and dealing with accidents, he ensures that such rescues and accident responses are carried out successfully. The public order and environmental protection department is responsible for maintaining order at the scene and setting up barriers, as well as evacuating the surrounding residents and passersby. 5. The Safety and Quality Department exercises effective supervision over the safety of emergency rescue operations and the control of personnel entering the accident site, in accordance with the approved plans for rescuing those in distress and dealing with accidents, as well as the provisions of the relevant regulations. 6. The production scheduler is responsible for recording the time, location, and details of accidents, and immediately reporting these details to the company’s general manager, chief engineer, safety and quality department, emergency response team, fire department, security department, as well as other relevant leaders and units. In accordance with the manager’s instructions, this person coordinates the efforts of all parties involved and assists the manager in carrying out emergency response and disaster management actions. 7. The director of the methanol workshop and its team members are responsible for checking the number of employees in their respective areas. Measures shall be taken to organize their evacuation to safe locations, and the details of the accident as observed at the scene, including its scope and causes, must be reported in detail to the company’s production control team. They must also be ready to follow the company’s orders at any time in order to carry out rescue and disaster management tasks. III. Emergency response procedures for accidents: Accident occurs → Cut off gas and power supplies → Report the incident → Company’s control team takes action → Safe self-rescue, evacuation of people, and isolation of the site. In the event of major disasters such as fires, the staff on duty in the methanol workshop must immediately report to the company’s production control team, providing information including: (1) The time and location of the accident, as well as basic details about it ； (2) Brief account of the accident and number of people in distress ； (3) Preliminary assessment of the nature of the accident and measures taken. The dispatch duty officer must keep detailed records, report the incident immediately to the on-duty supervisor, and at the same time inform the company’s general manager, chief engineer, fire department, as well as other company leaders about what has happened. Relevant personnel should be summoned by phone to wait in the dispatch room, and the details of the incident should be reported to the company’s dispatch team and the responsible managers. Until the commanders arrive, the company’s on-duty supervisor is responsible for directing the rescue efforts. Based on the various circumstances and information at its disposal, the command center determines the nature of the accident and the extent of the disaster, formulates emergency rescue plans and measures, and assigns the control room to notify the workers involved so that they can take emergency precautions. IV. The major hazard source identified is the methanol intermediate tank, which is located on the west side of the distillation area; it is adjacent to a 20,000 m³ gas holder to the south, and the synthesis system is to its north. The tank area contains one 170 m³ storage tank for pure methanol, with the tanks located relatively close to each other. The main substance stored in these tanks is pure methanol, and the potential hazards associated with them include explosion, fire, and methanol poisoning. It is considered a major hazard source and requires focused monitoring and management. V. Hazards of the hazard source: The explosive limit of methanol vapor in air is 6–36.5%, its flash point is 12–16°C, and its auto-ignition temperature is 473°C. The minimum oxygen content required for ignition of methanol when it is filled with N2 is 10.3%, whereas when filled with CO2, this value is 13.5%. The maximum flame propagation speed of methanol vapor when burning in air is 0.572 m/s. Similarly, its combustion speed is 1.05 m/s, and when methanol vapor burns in air, the highest temperature of the flame can reach 1750°C. The burnout rate of methanol from the free surface is 1.2 mm/min or 57.6 kg/m2·h. The pressure during the explosion of a mixture of methanol and air to form an explosive substance is 0.84 MPa. Project Scope Water content %: 0, 15, 45, 60, 75, 85, 90, 95 Natural temperature (°C): 464, 500, 545, 565, 585, 600, 610 No ignition point Flash point (°C): 8, 11, 22.75, 30, 44.25, 58.75, 65.25 No flash point Explosive limit temperature for mixtures of methanol at different concentrations: Methanol content (%): 100, 70, 40, 10, 3 Lower explosive limit temperature (°C): 7, 15, 30, 60 No explosion Flash point (°C): 39, 49, 55, 76 No explosion Autoignition point and flash point of methanol-water solutions at different concentrations: Methanol is highly toxic to humans; consuming 5–10 ML can cause blindness, while 30 ML can be fatal. The maximum allowable concentration of methanol in workshop air is 50 mg/m². Acute inhalation poisoning often has an incubation period of 8 to 36 hours, with symptoms such as headache, dizziness, muscle weakness, nausea, vomiting, abdominal pain, back pain, restlessness, cold and wet limbs, eye pain, blurred vision; diarrhea may occur occasionally. Visual impairment can progress rapidly to blindness, during which the pupils may dilate or constrict, and the light response may be delayed, followed by atrophy of the optic disc. In severe cases, bradycardia of the myocardium can occur. Symptoms such as acidosis, convulsions, and shock. Chronic effects: Workers exposed to low concentrations of methanol over a long period may experience symptoms primarily related to neurasthenia and autonomic nervous system dysfunction, as well as mucosal irritation and vision decline. III. Accidents and Handling 1. Tank leakage: ① Report to the control room immediately and call 119 for the fire department, as a precaution. ②All access routes to the tank area must be blocked; unauthorized personnel are strictly prohibited from entering or leaving. ③Use the methanol pump J40508 to transfer the methanol from the leaking tank to another tank until it is completely emptied. ④Isolate the leaking tank and purge it with nitrogen for protection. 2. Leak in the tank and fire: ① Immediately report to the control room and call the fire department at 119. ②The methanol synthesis and distillation systems were immediately shut down urgently. ③Activate the foam fire extinguishing system to suppress the initial fire, while directing the water guns at the leak site to spray water. ④Start the spray pump to cool down the tank. ⑤All access routes to the tank area must be blocked; unauthorized personnel are strictly prohibited from entering or leaving. ⑥Use a methanol pump to transfer the methanol from the leaking tank to another tank until the leak stops. 3. Fire in the methanol pipeline: ① Immediately shut down the methanol synthesis and distillation systems on an emergency basis. ②Immediately spray water at the point of fire using fire-fighting water to cool down the pipes. ③Close the valves that connect this pipe to other pipes and equipment. ④Start the spray water pump to cool down the tank, in order to prevent fire from spreading to the tank area. ⑤Call 119 for the fire emergency, and report the situation to the control room at the same time. 4. Ground fire: ① Extinguish it immediately with a fire extinguisher. ②Use a water gun to flush the remaining methanol on the ground into the sewer, and dilute the methanol with enough water to reach a concentration of 0.1%. ③ If the fire gets out of control, call the fire department immediately at 119, and also inform the control room. 5. Personnel poisoning: ① Call the emergency number 112 immediately, and report to the control room at the same time. ②It is crucial to calculate the time needed so that the doors can be opened at any moment to allow ambulances to enter; every second counts. ③Find out the cause of the poisoning; do not drink water or eat anything for now. ④If the smell of methanol in the air is too strong, wear a methanol gas mask and go to the site to find out the cause. 6. Methanol in the eyes: ① Immediately immerse both eyes in clean water, keep them open, move the head back and forth, and blink the eyelids. If possible, continue to rinse the eyes with fresh water until emergency responders arrive. ②Call the emergency number 112 immediately, and report to the control room at the same time. IV. Emergency response measures for the distillation unit: 1. Immediately shut off the steam inlet valves of the reboiler in tower C40501 and the reboiler in tower C40504. 2. Stop the operating pumps J40501, J40502, J40503, J40504, J40505, J40506, J40506, J40507, etc. 3. Close the C40510 feed main valve, the self-regulating valves of FV40512 (pressurized Scrape back flow), FV40513 (atmospheric pressure Scrape back flow), LV40503 (pre-tower liquid level), and LV40511 (atmospheric pressure reflux tank liquid level), as well as the upstream and downstream isolation valves. 4. Turn off the self-regulating valves PIC40503, PIC40509, PIC40511 And the upstream and downstream isolation valves. 5. Notify the dispatcher promptly; if it’s not possible, handle the matter first and report afterwards. 6. Determine the processing method based on actual conditions. Note: After parking, pay attention to the pressure of each tower system; if necessary, fully open the vent valves or use N2 protection to prevent overpressure or negative pressure.