To ensure a longer service life for glass-lined equipment and reactors, in addition to taking appropriate protective measures during installation and use, strengthening the maintenance of glass-lined equipment plays a crucial role. During the maintenance process, the following aspects should be noted:
Upon completion of each reaction, a thorough inspection must be conducted using a light (an internal inspection of key equipment, if possible), for any cracks or chipped glass damage. Prompt repairs must be made before usage is allowed.
1.2 Regular cleaning is required.
(1) The outer shell of the drum: The metallic surface outside the glass frit layer is designed to prevent corrosion from acidic fumes and liquids, thereby avoiding a reaction with the metal surface that produces hydrogen, leading to the "scale explosion" of the glaze. In case of any acid liquid leakage, immediate cleaning and sealing should be carried out. Protective paint should be applied regularly.
(2) Jacket: During use, there may be a decrease in the thermal conductivity of the equipment or the occurrence of scale spalling on the porcelain surface. The possible cause is that during operation, acidic impurities may fall into the circulating water, forming atomic hydrogen on the steel surface. This hydrogen can penetrate the steel and create pressure at the interface between the porcelain layer and the steel surface, causing the porcelain to scale off in a fish-scale pattern or, in some cases, the steel surface can develop a scale layer, severely deteriorating the equipment's thermal conductivity. Therefore, whether for heating or cooling, the medium in the jacket should be neutral. To prevent corrosion, the jacket should be cleaned regularly. If descaling agents are used, they should be applied as quickly as possible, followed by repeated rinsing of the jacket with water. The residual fluid should be tested to ensure it is neutral.
(3) Inside the drum: Cleaning can be scheduled based on the specific reaction conditions. Avoid using strong acid solutions, especially those with a pH below 3. Instead, use a 1.5% to 2% sodium hypochlorite solution. If there are solid materials adhering to the drum, do not use metal or hard rods for scraping.
1.3 Storage of Glass Lined Equipment: All glass lined equipment components not in use or temporarily out of service should be protected and stored properly to prevent dings and rain damage. Be cautious to prevent water from entering the jacket or the thermometer sleeve, as water freezing during winter can crack the porcelain layer.
1.4 Routine Maintenance
(1) Units utilizing glass-lined pressure vessels are responsible for conducting daily maintenance and care for the pressure vessels, their safety accessories, protective devices, measuring and control equipment, and auxiliary instruments. Any anomalies found should be addressed promptly and documented. Additionally, a regular inspection system for safety accessories should be established, with periodic inspections conducted in accordance with the provisions of the "Regulations for Periodic Inspection of Pressure Vessels" and related safety technical specifications.
(2) Regularly inspect the condition of transmission components and flange seals, and replace the transmission units and lubricating fluids in the mechanical seal cavities on a schedule. Ensure proper lubrication of all moving parts and promptly replace any worn-out flange gaskets.
1.5 Hazard Handling: Units utilizing glass-lined pressure vessels should promptly inspect and test any vessels experiencing malfunctions or abnormal conditions to eliminate accident hazards. For pressure vessels with severe hazards and no value for modification or repair, they should be immediately scrapped and the de-registration procedures should be completed.
6-Yearly Inspection
(1) Entities using glass-lined pressure vessels should conduct annual inspections of the pressure vessels, which must include checks on the safety management of pressure vessels, inspections of the pressure vessel itself and its operating conditions, and checks on the safety accessories of the pressure vessels. Perform a single high-voltage DC test of 3 to 5 kV on the glass-lined porcelain surface inside the tank.
(2) The annual inspection can be conducted by professionals from the pressure vessel user unit or entrusted to a qualified special equipment inspection institution.
1.7 Regular Inspection
Users of glass-lined pressure vessels should submit a regular inspection request to the special equipment inspection institution one month prior to the expiration of the regular inspection validity period. Upon receiving the regular inspection request, the inspection institution should conduct the inspection promptly. The regular inspection institution, personnel, and cycle, as well as the content of the regular inspection, should be implemented in accordance with the TSGR0004-2009 "Safety Supervision Regulations for Fixed Pressure Vessels."
1.8 Procurement, Discontinuation, Transfer, and Relocation of Glass-Lined Pressure Vessels
(1) Users of glass-lined pressure vessels must not purchase scrapped glass-lined pressure vessels. The shutdown, transfer, or relocation of equipment should be strictly handled in accordance with the relevant regulations of inspection and usage registration.
After being out of use for 2 years or after being transferred from an external unit or within the same unit, glass-lined pressure vessels must be inspected in accordance with the relevant regulations for periodic inspections prior to use, and they must undergo a pressure test.
