【Weekly Topic】Production Technology: Things to note in winter? 2011.13~11.20

1. In winter, the primary concern is preventing freezing. Regularly inspect pipes and equipment prone to freezing to prevent ice formation. Particular attention should be paid to areas with low flow that are often at a standstill. 2. In winter, with its cold and windy conditions, people tend to feel reluctant to conduct inspections, which increases the likelihood of equipment failures ； 3. In cold weather with slippery roads, people working outdoors are prone to accidents such as falls and other injuries ； 4. The climate is often dry in winter, which can lead to the accumulation of static electricity in the human body; it is important to discharge this static electricity promptly ； 5. In winter, the temperature difference between equipment and the environment increases, so it is necessary to pay attention to equipment maintenance.

Winter anti-freezing and anti-condensation measures are key to ensuring safe production. To prevent all types of freezing and condensation incidents, these measures should be carried out in accordance with the principle of \"prevention first, elimination as a supplement\", taking into account the characteristics of the facility. Strengthen the receipt, delivery, utilization, and management of items prone to freezing and solidification. Adhere to relevant rules and regulations to ensure safe production. The specific measures are as follows: (1) Before winter sets in, conduct a comprehensive inspection of the equipment to make proper preparations for winter. This includes providing thermal insulation and steam tracing for equipment and pipelines; checking whether there are any dead ends in the equipment, pipelines, and valves; and ensuring that drain valves function properly. Additionally, inspect doors, windows, glass, heating systems, etc. (2) Equipment and pipelines that are shut down in winter must first be cleaned with steam; for those that cannot be cleaned with air, the drain valves at the lower positions must be opened to remove any accumulated water. (3) For equipment that is temporarily shut down in winter, it is necessary to ensure a slight flow of return water or steam to prevent the pipelines from freezing. (4) During winter operations, the steam main lines, the feedwater and return water lines, as well as the steam traps on the heat tracing lines should have their valves slightly opened depending on the temperature conditions, in order to prevent the valves and lines from freezing damage; the steam traps must remain unobstructed and functional. (5) The drain valves or vent valves on the fire steam lines throughout should be slightly opened to allow steam to escape and prevent freezing. (6) For the industrial air and purified air of the equipment, inspection and water cutting operations should be intensified, and the rubber hoses for exhaust steam in various locations should be connected to the sewer for condensate discharge. (7) If it is found that the valve has frozen and will not open, especially in the case of cast-iron valves, it is prohibited to strike it with a wrench or other tools. Instead, the valve should first be closed, then warmed up using steam (or water) before attempting to open it again. (8) During winter, the heat tracing lines of all pipelines must be kept supplied with steam and water at all times to ensure smooth operation. For the condensate pipes leading to the atmosphere and the drainage valves, a method of slight steam and water discharge should be employed. (9) When the plant is shut down for winter due to a lack of steam and water supply, air should be used to thoroughly purge all steam lines and water lines, isolate them from the main systems outside the plant, or drain them at appropriate locations. (10) During the winter shutdown period, all heating equipment, pipeline trace heaters, and steam systems should generally continue to receive a small amount of steam supply, while all coolers and cold water lines should also continue to have a slight flow of water to keep the pipelines unobstructed and prevent them from freezing. (11) In winter, the degree of steam and water drainage can be adjusted according to morning, noon, evening conditions and temperature levels; regular inspections are necessary, as this cannot be done once and for all. (12) When a problem is detected with the instrument bypass heater, notify the instrument maintenance team promptly to handle it. (13) Strengthen routine inspections to prevent freezing, ensure smooth operation, and maintain safe production. (14) To prevent the medium inside the standby pump from freezing, the following measures should be taken: a. Close the inlet and outlet valves, open the vent valve and the drain plug on the pump body to drain all accumulated liquid from the pump. b. Slightly open the bypass valve of the pump outlet check valve and open the pump inlet valve; this allows the fluid from the pump in use to flow back through the standby pump body to prevent freezing.

Be careful to prevent freezing, slipping, fires, poisoning, etc~

What’s written above is already quite specific. Let me share my views: the South is different from the North, and production units of different types also vary. However, it essentially comes down to these points: 1. Safety – due to the impact of climate and weather changes on the environment, there may be certain safety hazards that need to be addressed promptly, either by eliminating them or by warning employees. 2. Process: The impact of seasonal changes on the production process. Since most chemical reactions are affected by temperature, it is necessary to fully consider the effects of lower temperatures on production stability and efficiency. 3. Equipment: Whether equipment can maintain normal operation under the influence of temperature. For example, will pipes and pumps freeze? Will hydraulic equipment operate more slowly due to low temperatures?
4. Efficiency: Will product sales and transportation be affected? What about raw material prices? After all, production costs are the key factor here.
5. Management: It’s crucial to establish appropriate regulations based on specific circumstances, and to ensure they are effectively communicated and implemented.

Winter is good for our businesses in the south; it is often the period of the year with the highest output and the best quality. There is no freeze protection issue. As the ambient temperature drops, the outlet temperature of the cooling tower also decreases, thereby **improving** the operating efficiency of the vacuum crystallizer. Natural gas and heat have little impact; overall, the equipment failure rate also decreases. Interestingly, due to the decrease in the temperature of the circulating water, the amount of condensation in the gas pipelines does not increase as much as one might expect, because the temperature at the outlet of the compressor also decreases. The conductivity of raw water will gradually decrease to its lowest level in December and remain so until around May. Friends in the Yangtze River Basin might want to compare the data. This is the period when the cost of the demineralized water system is at its lowest.

Winter prevention measures for chemical manufacturing enterprises: Taking proper actions to prevent cold, freezing, fires, gas poisoning, and slips in winter is crucial for avoiding fire and explosion accidents during this season. 　　I. Cold protection 　　Poor insulation and cold protection in workshops and factories can lead to the freezing and cracking of water pipes and cooling pipes, thereby creating a risk of fires and explosions. To implement cold-weather prevention measures, the following points should be addressed. 　　1. Before winter arrives, it is necessary to thoroughly carry out insulation and cold protection work for factory buildings and infrastructure. 　　2. Before the heating season begins, the heating equipment must be adjusted and repaired, and pressure testing for leaks must be carried out to ensure safety during the heating period. 　　3. Some chemical raw materials and products that are prone to deterioration at low temperatures should be kept warm. Additionally, heat-sensitive raw materials and products should not be placed near stoves or radiators, nor should they be placed on heating pipes, to prevent fusion and explosions. 　　4. It is necessary to ensure proper insulation and protection against freezing for fire extinguishing equipment. If a chemical foam fire extinguisher is exposed to low temperatures, the solution inside its tank and container will freeze into solid blocks; this expansion can damage the extinguisher and render it unusable. Therefore, chemical foam fire extinguishers must be stored in indoor areas at normal temperatures. 　　II. Antifreezing 　In the northeastern region of China, winter temperatures generally range from minus 20°C to minus 40°C; therefore, antifreezing measures are extremely important for chemical manufacturing enterprises. 　　1. Prevent raw material coagulation. At a petroleum plant, the cold weather caused the crude oil in the casing crystallizer to solidify, preventing the equipment from operating properly. The workers on duty used steam to flush it, which caused the temperature inside the casing to rise sharply, resulting in the liquid ammonia inside the casing being ejected. The operator was knocked over into the oil tank and died on the spot. 　　2. Prevent pipeline freezing. An operator at a chemical plant saw that the outlet pipe at the furnace surface had frozen, so he used fire to heat the outlet valve during downtime, causing the steam inside the furnace to build up to excessive pressure and resulting in an explosion. In another small chemical plant, ice formed on the valve stem of the charging valve of a distillation kettle, causing the stem to be pushed out. The resulting increase in pressure inside the kettle forced the lid open, allowing large amounts of benzene gas to escape; this gas then exploded upon coming into contact with an open flame. 　　3. Prevent equipment from becoming brittle and cracking. The water washing tower in the compression workshop of a small fertilizer plant experienced brittle fracture at the edges of its three levels due to low temperatures, as well as issues related to the material used in the equipment and welding techniques, which led to an explosion and a serious accident. 　　III. Fire Prevention Fire prevention is very important in winter, and the following aspects should be taken into account: 1. Strengthen the management of fire use. During winter heating, more stoves are used in workplaces and employee dormitories. The furnace should be installed properly, the chimney should be placed in the right location, and no flammable materials should be kept around it. For fire use in production, fire operation procedures must be followed as required, a fire safety responsibility system must be implemented, and the fire must be extinguished once everyone has left. Do not use steam for direct heating, and never dry clothes over a radiator to prevent fires. At operational posts involving exothermic chemical reactions, boiling, drying, and other processes in the chemical industry, fire prevention regulations must be strictly enforced to reduce the occurrence of disasters and accidents. 　　2. Do not misuse electric heating devices. Do not pull temporary wires randomly, and copper and aluminum wires should not be connected together. Use electrical equipment in accordance with the regulations, avoid overloading it, and turn off used heating devices promptly. In meeting rooms or clubs, direct exposure to strong light should be prevented to avoid scorching the curtains or other flammable materials. Home appliances in dormitories and duty rooms should be used and installed properly to prevent accidental fires. 　　IV. Prevention of gas poisoning Gas mainly refers to carbon monoxide. Gas leaks can occur in both the production process and daily life due to poor management and other reasons. Gas can not only cause fires or explosions, but also lead to poisoning or even death. Especially in winter, due to poor air circulation indoors, leaked gas tends to accumulate. Combined with heating and the increase in equipment, it further increases the risk of gas poisoning. To prevent gas poisoning, it is necessary to: l. Regularly inspect equipment to prevent leaks from gas generators and pipelines. 　　2. Strengthen equipment sealing and indoor ventilation, especially in workshops prone to gas generation. 　　3. Strictly follow the operating procedures; in the event of carbon monoxide presence, it must be purified promptly. Personal protective equipment and monitoring measures are required in areas with high concentrations of carbon monoxide. 　　4. Industrial and domestic gas must be separated to prevent toxic gases or exhaust from entering the domestic gas system. 　　5. Pay attention to personal protection. Those working in areas with gas hazards must wear gas masks; it is essential to use air-supplied gas masks. 　　6. Provide employees with enhanced safety education on preventing gas poisoning, and disseminate knowledge on self-rescue and mutual rescue. 　　7. For on-duty personnel at the workplace, if using a stove for heating, do not seal it shut. 　　8. Persons with significant neurological or cardiovascular diseases, severe anemia, pregnant women, minors, and older workers should not work in positions where carbon monoxide is generated. 　　V. Anti-slip: In winter, due to the cold weather and unmelted snow, roads become very slippery. When working outdoors, especially in high-altitude outdoor tasks, it is necessary to thoroughly inspect the equipment and implement additional anti-slip measures to prevent falls from heights and injuries.

1. Protection against freezing is necessary, especially for chemical plants in the northern regions; primary water, circulating water, demineralized water, boiler water, and even steam condensate can all be damaged by freezing, leading to forced shutdowns； 2. It is also prohibited to start or stop the vehicle in winter for freeze prevention reasons ； 3. Anti-slip and anti-poisoning ； 4. Anti-static.

1. For freeze protection of equipment and pipelines, the main task is to check whether there are any dead ends in the equipment and pipelines and to address them. 2. Develop a plan and establish preventive measures to prevent freezing when the vehicle is parked. 3. Personnel management: It’s cold in winter and the ground is slippery, so this helps to reduce casualties among personnel.

Reply 1# sun-rock The “four defenses” in winter include protection against freezing, slippage, fire, and poisoning. With the advent of winter, for chemical enterprises—especially those located in cold climates—what might seem like minor issues to other companies, such as standing water on the ground or leaks in pipelines or equipment, can easily lead to major accidents if not addressed and prevented in a timely manner during winter. In terms of freeze protection, companies should thoroughly inspect for leaks in equipment and pipelines, as well as the insulation systems. For certain critical pieces of equipment, dedicated personnel should be assigned to conduct regular inspections, addressing any issues that arise promptly ； Regarding slip prevention, water accumulation on the floor should be dealt with promptly. During inspections, staff should check whether there is ice on the floor and stairways to avoid slips and falls ； In terms of fire prevention, it is necessary to closely monitor important potential fire hazards. Fire-fighting equipment must be kept in good condition and readily available. When carrying out hot work, the ‘Six Prohibitions’ must be strictly observed ； In terms of poisoning prevention, leaks from equipment and pipelines must be addressed, and protective clothing must be worn as required during startup and shutdown operations; procedures must be followed strictly to avoid any violations. Furthermore, companies should provide relevant skill training tailored to the production challenges of winter, explain common causes of accidents, and regularly organize drills for accident prevention and emergency response, in order to enhance employees’ awareness of safety in winter and their capabilities in emergency situations. This is common sense that is entirely normal for employees in chemical companies. But it is these seemingly ordinary common senses that often become the cause of accidents.

Reply to 1# sun-rock: 1. Be careful to prevent freezing; 2. Perform temperature changes gradually