Is it necessary to install on-site level gauges for liquefied hydrocarbon spheres?

Thread Content

Liquefied hydrocarbon spheres tanks require on-site indicating instruments, which can be provided by on-site level gauges or by the on-site level indication function of remote transmission instruments. A magnetic flap level gauge can be used as an in-situ level gauge. Glass plate level gauges are not suitable for in-situ level measurement. Where the standards and documents specify something, those specifications shall prevail. Examples of reference standards and documents are as follows: SH 3136-2003 Code for Safe Design of Spherical Storage Tanks for Liquefied Hydrocarbons. 1 Scope 1.1 This code is formulated to standardize the safe design of spherical storage tanks for liquefied hydrocarbons and their accessories, improve the safety of such tanks, and prevent or reduce the occurrence of accidents. 1.2 These specifications apply to the safety design of spherical storage tanks for liquefied hydrocarbons and their accessories in petrochemical plants and storage and transportation facilities. 5 Instruments 5.3 Level 5.3.1 Liquefied hydrocarbon spherical storage tanks shall be equipped with local and remote level gauges; however, glass plate level gauges should not be used. The level gauge used should be safe and reliable, and the number of openings in the spherical liquefied hydrocarbon storage tank should be minimized as much as possible. Focus: Local level gauges should be installed, and it is specified that glass plate level gauges are not suitable. It is not specified whether a remote level gauge with an on-site level indication function can be used to replace the on-site level gauge. SH/T 3136-20XX (draft for comment, version published by the Ministry of Industry and Information Technology), which has an on-site level indication function to meet the requirements for on-site display. Examples of devices with on-site level indication include the gauge mounted next to the tank for radar or servo level gauges. SH/T 3136—20XX Safety Design Code for Spherical Storage Tanks of Liquefied Hydrocarbons (Draft for Comment, version published by the Ministry of Industry and Information Technology) 1 Scope This code specifies the technical requirements for the safe design of spherical storage tanks for liquefied hydrocarbons, as well as the valves, instruments, safety accessories, and related measures that are directly connected to them. These specifications apply to the design of spherical storage tanks for liquefied hydrocarbons and related accessories. 5 Instruments 5.3 Level Measurement 5.3.1 Liquefied hydrocarbon spherical storage tanks shall be equipped with at least two sets of remote continuous level gauges; it is advisable to use level gauges based on different measurement principles, and at least one of these sets shall have the capability to display the level locally. Focus: It features an on-site level indication function to meet the requirements for on-site display. Examples of devices with on-site level indication include the gauge mounted next to the tank for radar or servo level gauges. AQ 3059-2023 Safety Management Specifications for Liquefied Hydrocarbon Storage Areas in Chemical Enterprises 1 Scope This document specifies the general requirements, planning and layout, design, procurement of key equipment and materials, construction quality management, commissioning, operation management, inspection and maintenance management, as well as emergency management for liquefied hydrocarbon storage areas within chemical enterprise campuses. This document applies to the safety management of newly built, expanded, or renovated liquefied hydrocarbon storage areas within the premises of chemical enterprises (including petrochemical, coal chemical, fine chemical industries, etc.), as well as existing liquefied hydrocarbon storage areas. This document is not applicable to the safety management of liquefied hydrocarbon storage areas such as liquefied natural gas receiving stations, natural gas liquefaction plants, underground rock caverns used for liquefied hydrocarbon storage, liquefied hydrocarbon storage tanks in oil and gas fields and purification plants, LNG storage tanks produced from coalbed methane, port liquefied hydrocarbon storage tanks, as well as urban gas supply stations and LPG/LNG filling stations. 6.6 Automatic Control 6.6.2 For newly installed pressure-type storage tanks for liquefied hydrocarbons, the level measurement instruments should be equipped with 2 sets of instruments for continuous level measurement and 1 high-high level switch, or with 3 sets of instruments for continuous level measurement. Liquefied hydrocarbon pressure storage tanks should be equipped with high liquid level alarms, low liquid level alarms, high-high liquid level alarms, and low-low liquid level alarms. The high-high liquid level alarm should trigger the interlocked shutdown of the tank’s feed emergency shut-off valve. Focus: Local level gauges and local indicators are not mentioned. “Regulations on Safety Technology Management for Liquefied Hydrocarbon Spherical Tank Areas in Sinopec” 4.4 Instrumentation and Automation 4.4.3 Liquefied hydrocarbon spherical tanks shall be equipped with local and remote level gauges. Local level gauges can be magnetic flap level gauges, steel belt level gauges, or radar or servo level gauge indicators installed beside the tank. When the local level gauge is a radar or a servo tank-side indicator, the spherical tank shall also be equipped with a different type of remote level measuring instrument. Focus: It is specified that for in-situ level gauges, magnetic flap level gauges, steel belt level gauges, radar level gauges, or servo level gauge-type indicators can be used. Su Emergency [2019] No. 53, \"Basic Requirements for Inherently Safe Diagnosis and Management\" I. Diagnosis of Major Hazards (1) Automatic control of raw material and product storage tanks as well as those in processing units: 1. Flammable liquid storage tanks, toxic liquid storage tanks, cryogenic storage tanks, and pressure vessels with a volume of 100 m3 or more must be equipped with remote sensing instruments for continuous level measurement as well as local level indicators; in addition, high-level alarms must be installed. Floating roof storage tanks and tanks equipped with extraction pumps must also have low-level alarms ； Pressure vessels containing flammable and toxic media are equipped with high liquid level or high pressure interlocks to stop feeding. If the design plan or HAZOP analysis report requires the installation of an automatic interlock to shut down the pump and close the discharge valve at extremely low liquid levels, such requirements must be met. Focus: It is specified that the pressure tank should be equipped with an on-site level indicator. It is not specified whether a remote level gauge with an on-site level indication function can be used to provide on-site level indication. From a standard terminology perspective, having an on-site level indication function meets the requirement for on-site level indication. SH/T 3007-2014 Code for Design of Tank Areas in Petrochemical Storage and Transportation Systems 1 Scope This code specifies the selection of storage tanks in tank areas of petrochemical storage and transportation systems, as well as the design principles and technical requirements for atmospheric, low-pressure, and high-pressure tank areas. These specifications apply to the design of storage tank areas for liquid materials (including raw materials, intermediate materials, finished products, and auxiliary production materials) in petrochemical and coal chemical enterprises, for new construction, renovation, and expansion projects. They are not applicable to the design of low-temperature and atmospheric-pressure storage tank areas for liquefied hydrocarbons and liquid ammonia, nor to natural gas liquefaction storage tank areas. 6 Pressure Storage Tank Area 6.3 Selection and Installation of Tank Instruments 6.3.2 For measuring the liquid level in pressure storage tanks, one set of remote transmission instruments and one set of local indication instruments should be installed; glass plate level gauges should not be used as local indication instruments.