Weekly topic on refining knowledge (technology): What are the safety measures for summer operations in refining plants? Issue 14, May 15-21, 2011

The last edit to this post was made by lijianhuai on 2011-5-13 at 16:34. Reply 1# lijianhuai: Precautions for various refining units: 1. Operators must take measures to prevent heat stress and avoid heat exhaustion； 2. During the thunderstorm season, be careful to take precautions against lightning strikes; ensure that the lightning protection and grounding measures for this device are in place ； 3. Adjust the speed of each air-cooled fan according to the temperature until the process requirements are met ； 4. When cleaning oil tanks and towers by steam, be cautious of heavy rain and temperature drops to prevent damage to the equipment due to vacuum extraction ； 5. Prepare an emergency plan to prevent power outages and equipment malfunction during thunderstorms ； 6. Ensure proper separation of clean and dirty water during rain ； 7. Strengthen inspections, especially to check for internal leaks in the high-level venting systems; it is advisable to use blind plugs to prevent fires caused by lightning. Any issues detected should be addressed promptly and properly.

Do a good job in the “four summer prevention measures”; proper lightning protection measures should be in place in the tank area, and the equipment’s grounding facilities must be complete

Due to the special nature of the feedstock processed in delayed coking units, a high downtime rate is a common problem among similar units across the industry. A time allocation schedule has been established for each production step, specifying the control parameters and precautions for each time period. Analysis of the operation status of the dry gas filter is carried out, and the pressure difference between the inlet and outlet as well as the pressure at the compressor outlet are monitored on a daily basis; any pressure buildup is addressed by switching systems promptly. Monitor the neutron level gauge in the coke tower carefully; if any problems arise, add antifoam agent promptly to prevent the foam layer from becoming too thick. They closely monitored the properties of the raw materials and adjusted the operating parameters of the unit as needed, reducing the recycle ratio from 0.30 to 0.15. At the same time, not only is the content of coke powder in the oil and gas at the top of the coke tower analyzed in a timely manner, but the pressure differences in the recycle filter and the radial filter at the bottom of the distillation tower are also continuously recorded. By adjusting the heat exchange process, the heat exchange between diesel and softened water was changed to heat exchange with circulating water, thereby reducing the temperature of the diesel leaving the unit to below 60°C. The special maintenance team for the workshop heating furnaces assigns dedicated personnel to prepare trend charts of the tube wall temperature and pressure drop at the inlet and outlet of the furnaces on a daily basis. They monitor the trends in tube wall temperature at all times and adjust the operating parameters as needed to delay coking, thereby ensuring the safe and stable operation of the equipment.

High temperatures in summer: 1. Operators must take measures to prevent heat exhaustion; the temperature of indoor air conditioning should not be set too low to avoid catching a cold, and medicines should be kept on hand to prevent heat stroke. 2. During the thunderstorm season, be careful to take precautions against lightning strikes. Check whether the lightning protection and grounding measures for this device are in place, and also prepare emergency plans in case of power fluctuations affecting the device. Ensure proper separation of clean and dirty water when it rains. 3. Adjust the speed of each air-cooled fan according to the temperature until the process requirements are met. 4. Strengthen inspections, identify problems, and address them promptly. It is also necessary to monitor the performance of each computer at the control station, in order to prevent crashes due to excessive temperatures of the computers, which could lead to accidents

The main ones are: 1. Heat protection for personnel； 2. Prevent overpressure and overheating caused by vaporization at high temperatures in storage tanks ； 3. Prevent the circulating water temperature from exceeding safe levels, thereby avoiding operational failures in other equipment as well as the heat exchange equipment ； 4. To prevent lightning strikes, it is necessary to conduct a thorough inspection of the grounding facilities for electrical equipment ； 5. To prevent heavy rainfall, it is necessary to clear the drainage system ； 6. To prevent strong winds, it is necessary to check all fastening devices and power supply lines ； 7. Protect the products from direct sunlight and reduce the quantity stored ； 8. Electrical inspections, replacement of faulty circuits as well as equipment with leakage or explosion hazards ； 9. Establish a temporary command team for summer safety production and formulate emergency response plans.

Reply to 1# lijianhuai: 1. First, carry out proper measures for preventing the four hazards in summer； 2. There are many thunderstorms in summer; it is necessary to check the equipment’s lightning protection and anti-static measures properly, and the flood drainage ditches should also be cleaned in advance ； 3. During the summer, when temperatures are high, spray systems should be installed in tank areas and storage tanks according to relevant standards to help reduce temperature. 4. As the weather is humid in summer, motors need to be rotated regularly to prevent moisture buildup.

One more thing: Adjusting production according to the temperature difference between day and night helps ensure stable production.

Refining unit: 1. Release pressure from the pipelines and equipment that are not in use to prevent them from cracking due to thermal expansion and contraction. 2. Check whether the insulation layers of high-temperature equipment and pipelines are damaged; any damage should be repaired promptly to prevent stress cracking in the welds of the equipment or pipelines during rainy weather. 3. Check for any leaks in the vent line at the top of the tower. 4. Take precautions to avoid heat stress and arrange work reasonably. 5. Increase the circulation cooling water flow for each pump according to actual conditions

I. Protection against high temperatures 1. Preventing equipment from overheating. 2. Prevent materials from overheating. 3. Protection of workers from heatstroke (adjusting working hours, providing heatstroke prevention medications and drinks). II. Prevention of leaks and flooding: 1. Power distribution room. 2. Instrument room. 3. Device. III. Lightning Protection 1. Venting at high points. 2. Equipment grounding. 3. Tank sealing. 4. DCS, automatic control for lightning interference shielding. IV. Protection against power outages, voltage fluctuations, and electric leakage 1. Protection against external power outages and voltage fluctuations. 2. Internal power fluctuations. 3. Leakage due to water ingress into electrical equipment and wiring. V. Prevention of epidemics 1. Prevention of food poisoning. 2. Prevent pink eye.

Reply to 1# lijianhuai: Precautions for various refining units: 1. Operators must take measures to prevent heatstroke and keep themselves cool； 2. During the thunderstorm season, be careful to take precautions against lightning strikes; ensure that the lightning protection and grounding measures for this device are in place ； 3. Adjust the speed of each air-cooled fan according to the temperature until the process requirements are met ； 4. When cleaning oil tanks and towers by steam, be cautious of heavy rain and temperature drops to prevent damage to the equipment due to vacuum extraction ； 5. Prepare an emergency plan to prevent power outages and equipment malfunction during thunderstorms ； 6. Ensure proper separation of clean and dirty water during rain ； 7. Strengthen inspections, especially to check for internal leaks in the high-level venting systems; it is advisable to use blind plugs to prevent fires caused by lightning. Any issues detected should be addressed promptly and properly.