GB/T 50759-2022 in English

According to the requirements of Document JIANBIAO [2016] No.248 issued by the Ministry of Housing and Urban-Rural Development of the People's Republic of China - Notice on printing and distributing the development, revision and related work plan on engineering construction standards and codes in 2017, the drafting group has revised this standard through the extensive investigation and study, careful summarization of practical experience and reference to relevant international and foreign advanced standards and on the basis of widely soliciting for opinions.

The main technical contents of this standard are: general provisions, terms, basic requirements, layout, process and piping, instrumentation control, utility, fire-fighting, and safety, occupational health and environmental protection.

The main contents of the revision of this standard are as follows:

1. The applicable scope is expanded, i.e., the vapour recovery facilities for loading system of gasoline, naphtha, aviation kerosene, solvent oil, aromatic oil or oil products with similar properties in petrochemical enterprises and oil depots have been changed to the vapour recovery and treatment facilities for storage and loading systems of volatile and flammable liquids for petrochemical enterprises, coal chemical enterprises and oil depot projects, solving the standard application problem of vapour recovery and treatment facilities in tank farm and for shipping system;

2. According to the current relevant standards and specifications and environmental protection requirements, the control index requirements of organic gases in tail gas emitted by vapour recovery and treatment facilities have been modified to comply with relevant standards and specifications;

3. The vapour collection system has been specified according to the storage, loading and shipping systems respectively;

4. Safety measures for vapour collection system in tank farm and of loading facilities have been added.

The Ministry of Housing and Urban-Rural Development of the People's Republic of China is in charge of the administration of this standard.

Technical standard for vapour recovery and treatment facilities

1 General provisions

1.0.1 This standard is formulated with a view to ensuring the operation safety of vapour recovery and treatment facilities, improving working conditions, reducing vapour emissions, protecting the environment, saving energy and improving technologies.

1.0.2 This standard is applicable to the engineering design of vapour recovery and treatment facilities for storage and loading systems of volatile and flammable liquids for petrochemical enterprises, coal chemical enterprises and oil depot projects.

1.0.3 In addition to this standard, the design of vapour recovery and treatment facilities shall also comply with the requirements of the current relevant standards of the nation.

2 Terms

2.0.1
volatile and flammable liquid
flammable liquid with a true vapor pressure greater than 7.9 kPa (A) at corresponding temperatures during storage or loading

2.0.2
vapour
general term of volatile organic gas generated by volatile and flammable liquid during storage or loading and its mixtures with other gases

2.0.3
vapour concentration
percentage of volatile organic compound to total vapour volume

2.0.4
vapour recovery and treatment facilities
general term of vapour collection system, vapour recovery unit, vapour treatment unit and their supporting utility systems

2.0.5
vapour collection system
system for centralized collection of vapour passing through the top of the tank or the loading system closed gas pipeline and other process equipment during the storage or loading of volatile and flammable liquids. The vapour collection system of the tank is divided into two modes: direct connectivity and single tank and single control

2.0.6
vapour recovery unit
unit for recovering vapour by physical methods such as adsorption, absorption, condensation, membrane separation or their combination

2.0.7
vapour treatment unit
unit for treating vapour by chemical methods such as combustion, oxidation and plasma

2.0.8
direct connectivity
connection mode of two or more tanks with the same or similar storage properties, i.e., gas phase spaces of those tanks are connected by pipelines (the gas phase branch pipelines of each tank have no exhaust control facilities such as pressure control valve and single call valve) to formed as a whole through pipelines, so as to achieve gas phase pressure balance between tanks

2.0.9
single tank and single control
connection mode of a single tank, i.e., vapour collection pipeline of each tank is provided with a single call valve or a pressure control valve and a pipeline detonation flame arrester to, if the vapour pressure is too high, discharge vapour into the vapour collection main pipe without considering the vapour balance between different tanks

2.0.10
dock-to-ship safety unit
safety protection facility installed on vapour collection pipelines at the wharf apron, which generally consists of quick shut-off valve, pressure detector, gas-liquid separator, oxygen content detector, vapour concentration tester, temperature detector, flame arrester, inerting system

2.0.11
tail gas
gas of vapour discharged to the atmospheric environment after being recovered or treated by vapour recovery units and vapour treatment units

2.0.12
liquid condensate
flammable liquid of vapour condensed due to changes in pressure and temperature

3 Basic requirements

3.0.1 The scale of vapour recovery and treatment facilities shall be comprehensively determined according to the nature and concentration of recovered and treated vapour, as well as the operating conditions and exhaust volume of those facilities.

3.0.2 The loading system of volatile and flammable liquids shall be equipped with vapour recovery and treatment facilities.

3.0.3 Internal floating roof tanks, vault tanks and low-pressure tanks for volatile and flammable liquids shall be equipped with vapour recovery and treatment facilities; if the concentration of vapour discharged from the tank meets the requirements of discharge limits and control indexes after taking control and discharge reduction measures, vapour recovery and treatment facilities may not be set up.

3.0.4 The storage and loading system of benzene, methylbenzene and xylene shall be equipped with vapour recovery and treatment facilities.

3.0.5 A vapour recovery unit should be equipped if the concentration of vapour discharged from the storage or loading system is greater than 30 g/m3; A vapour treatment unit should be equipped if the concentration of vapour discharged from the storage or loading system is less than or equal to 30 g/m3 or the vapour is difficult to be recovered.

3.0.6 The content of emitted organic gas in tail gas shall meet the requirements of relevant national pollutant control indexes.

3.0.7 Liquid separation tanks should be set up in front of vapour recovery units and vapour treatment units.

3.0.8 In case of explosive gas, measures for the vapour pressure boosting equipment shall be taken to prevent internal sparks and flame spread.

3.0.9 The mode of flame arrester shall be comprehensively determined according to the vapour composition and its installation position, and the pressure drop under the design discharge rate should not be greater than 0.3 kPa.

3.0.10 The diameter of vapour pipeline for vapour recovery and treatment facilities shall be determined according to hydraulic calculation.

3.0 11 The design pressure of vapour pipeline shall not be lower than 1.0 MPa, and the design external pressure of vacuum pipeline shall be 0.1 MPa. The nominal pressure of vapour pipeline and vacuum pipeline system shall not be lower than 1.6 MPa.

3.0.12 Pipeline equipment for vapour recovery and treatment facilities shall meet the following requirements:

1 Seamless steel pipes should be adopted for the pipeline;

2 Steel valves shall be adopted for vapour pipelines;

3 The material and pressure level of pipe fittings (e.g., elbow, tee, reducer and pipe cap) shall be consistent with those of the connected pipeline.

3.0.13 Areas for the vapour recovery unit and vapour treatment unit shall be provided with combustible or toxic gas detectors. The detection of combustible or toxic gas shall meet the relevant requirements of the current national standard GB/T 50493 Standard for design of combustible gas and toxic gas detection and alarm for petrochemical industry.

3.0.14 Inlet pipelines of vapour recovery unit and vapour treatment unit shall be provided with low, temperature and pressure detection instruments; online vapour concentration detector and high-high concentration interlocking protection measures shall be provided on the vapour collection main pipe or the inlet pipeline of the vapour treatment unit.

3.0.15 The installation of tail gas emission pipelines and their accessories for the vapour recovery unit and vapour treatment unit shall meet the following requirements:

1 For the oil depot project, the height of the pipe orifice for tail gas emission shall meet the requirements of the current national standard GB 20950 Emission standard of air pollutant for bulk petroleum terminals;

2 For petrochemical enterprises and coal chemical enterprises, the height of the pipe orifice for tail gas emission shall be greater than 15 m above the ground;

3 The tail gas emission pipeline shall be provided with sampling port and flame arrester;

4 The pipe orifice for tail gas emission shall be 3.5 m higher than the platform or building roof within 10 m.

Foreword ii
1 General provisions
2 Terms
3 Basic requirements
4 Layout
5 Process and piping
6 Instrumentation control
7 Utility
8 Fire-fighting
9 Safety, occupational health and environmental protection
Appendix A Start-stop points of fire separation distance
Explanation of wording in this standard
List of quoted standards
Addition: Explanation of provisions