Winter anti-freezing

Insulation and heat tracing are the most effective; sometimes, during the production process, the two measures of ‘venting’ and ‘continuous flow’ cannot be implemented

Ensure proper insulation and heating; at the same time, inspect pipes and facilities with slow flow rates and install heating tubes to prevent freezing. After shutting down the system, all materials that are prone to freezing must be drained completely. It is best to purge these areas with nitrogen. In the case of water, it should be drained entirely, paying special attention to areas above check valves or those at the lowest points in bends where drainage lines may not reach – these areas should be thoroughly cleaned using air

Winter Anti-freezing and Anti-condensation Plan I. Preparation Notes Once the construction of the equipment is essentially complete, it is necessary to carry out trial operations with the material loaded into the system. If this takes place in winter, it is also essential to take measures to prevent freezing and condensation during these trials. To ensure that no pipelines, valves, or equipment get damaged, and to enable the trial operations to be completed successfully, this plan has been formulated. II. Basic requirements for anti-freezing and anti-condensation measures: Train operators in these tasks, ensuring that everyone is familiar with the key areas of the facility that require anti-freezing and anti-condensation protection; everyone must understand the relevant preventive measures and carry out regular inspections to ensure effective anti-freezing and anti-condensation practices. In anti-freezing and anti-condensation efforts, each heating pipeline, each pump and machine unit, each standby compression unit, as well as each water line bypass must have dedicated personnel in charge to ensure that no corner is overlooked, thereby guaranteeing the effective implementation of anti-freezing and anti-condensation measures and ensuring the safe and stable operation of the installation. III. Safety regulations for preventing freezing and condensation 1. Equipment that is in operation or temporarily shut down, as well as water and steam pipelines and control valves, must be equipped with measures to prevent freezing and maintain warmth; any accumulated water should be drained, or a system that maintains a slight flow of water or steam should be used, so as to achieve both prevention of freezing and energy savings. After shutting off the water and steam, it is necessary to purge thoroughly. 2. Blind flanges must be installed at the connections between the decommissioned equipment, pipelines, and the production system, and any accumulated water must be drained and the area cleaned thoroughly. For equipment left outdoors and those with open components, measures should be taken to prevent water and snow from accumulating and freezing, thereby damaging the equipment; for rotating equipment, it is necessary to increase the frequency of inspections and rotations. 3. Valve chambers, fire hydrants, and pipe trenches in low-temperature areas should be inspected one by one to drain any accumulated water, and anti-freezing and insulation measures should be taken. 4. During extremely cold seasons, greater attention should be paid to the maintenance and inspection of power supplies and wires. 5. The cooling water for pumps and compressors must not be interrupted, and standby equipment should be rotated as specified. 6. It is strictly prohibited to use high-pressure steam for heating; care must be taken to prevent high-pressure steam from entering the low-pressure system. The high-pressure and low-pressure steam return pipes must not be connected to each other. 7. Frozen pipes, valves, etc. must not be heated rapidly; they should only be thawed slowly using warm water or a small amount of steam, to prevent damage caused by sudden heating. 8. Whenever working at heights is undertaken, all water, snow, and ice accumulated in the work area must be removed before proceeding. 10. Strengthen the reporting system; any occurrence of freezing should be reported immediately to supervisors and higher-level departments. IV. Key areas for anti-freezing and anti-condensation measures 1. Utility systems 1) The main inlet and outlet pipes for steam, fresh water, cooling water, desalinated water, nitrogen, and low-pressure condensate. 2) Hot and cold flare main pipes 2. Process system: Drain lines for various containers ； Inlet and outlet lines for cooling water of various pumps, as well as drain and pre-warming lines ； Inlet and outlet pipelines for circulating water in each cooler, as well as bypass lines ； Each steam tracing line and its return line ； Pressure relief lines for various process pipelines ； Insulation of various process pipelines and equipment ； Insulation and heat tracing for each solvent pipeline. 3. Compressor building: Drain lines and exhaust lines for each unit ； Inlet and outlet lines for cooling water, as well as bypass circuits for each oil cooler ； Each seal gas pressure relief line ； Heating systems and their doors and windows glass. V. Key points for winter commissioning operations 1. When purging the system with nitrogen, condensate must be drained from areas such as glass panel level gauges and locations where liquid tends to accumulate at low points to allow air to pass through. 2. All heat tracing lines must remain unobstructed. 3. Keep the pump cooling water line unobstructed. 4. Ensure that the lubricating oil for the pump is free from water condensation. 5. The instrument air and nitrogen main pipes must remain unobstructed, and gas should be visible during drain operation. 6. The steam and low-pressure condensate systems must remain unobstructed. 7. All control and measuring instruments must be reliable and easy to use; during nitrogen purging, the instrument outlet pipes should also be drained to allow air to pass through. 8. When drying low-temperature equipment and pipelines, it is necessary to ensure that gas is visible at all exhaust points to confirm successful drying. 9. Ensure that the emergency pressure relief line is unobstructed before starting up. 10. Before starting the compressor unit and pumps, rotate the shaft slowly to prevent it from freezing and breaking. 11. During the initial cooling and pressurization of the system, these processes should be carried out slowly to prevent equipment damage caused by too rapid cooling or pressurization. VI. Measures for preventing freezing and condensation 1. Include measures to prevent freezing and condensation in the job responsibility system, emphasize these checks during regular inspections, and treat them as an important aspect of work. 3 Ensure frost and condensation prevention through 24/7 comprehensive monitoring, so that issues can be identified and addressed promptly. 4. Isolate the decommissioned equipment and containers to ensure their safety throughout the winter, prevent leaks from occurring on these equipment and containers as well as in the piping systems, and guarantee the proper progress of testing operations as well as the safe passage of the equipment and facilities through the winter. 5. Establish a anti-freezing and anti-condensation team to conduct random inspections and carry out strict evaluations of the implementation of anti-freezing and anti-condensation measures.