Background of tetrahydrothiophene detection
Tetrahydrophene, abbreviated as THT, is one of the important safety measures for natural gas in civilian use. There are multiple national regulations and standards that regulate it. Among them, the "Code for Design of Urban Gas" (GB50028-2006) standard stipulates that "when gas leaks into the air and reaches 20% of the lower limit of danger, it should be detectable." In its interpretation, it is further recommended that when using tetrahydrothiophene (THT) for odorization of natural gas, the dosage of odorant should not be less than 20mg/Nm3, and the terminal concentration should not be less than 8mg/Nm3. How to check the concentration of odorant at the end of the pipeline after odorization and record it to provide accurate basis for adjusting the odorization amount of natural valve stations, as well as ensuring the safe operation of gas, has become a problem that must be solved. In response to the actual detection problems encountered by major cities in China during the odorization process and the further requirements for tetrahydrothiophene odorization detection, our company has developed a natural gas organic sulfur compound (tetrahydrothiophene) detection gas chromatograph based on the requirements and testing methods for organic sulfur compound odorants for natural gas (GB/T19206-2003). After continuous improvement, we have successfully developed a gas chromatograph for detecting natural gas organic sulfur compounds (tetrahydrothiophene) on the GC-2020 basic gas chromatograph, which has high sensitivity and good stability, low detection limit, good reproducibility, easy operation, and moderate price. It is one of the important detection instruments for gas companies, oil and gas extraction, tar refineries, and biological gas production.
Detection principle of tetrahydrothiophene
Tetrahydrophene detector for natural gasThe determination of tetrahydrothiophene (THT) in natural gas is carried out using a flame photometric detector (FPD). Flame photometric detector (FPD) is a detector with high sensitivity and selectivity for sulfur compounds. After the sample is separated by a chromatographic column, it enters the detector FPD. FPD converts the optical signal into an electrical signal, which is then amplified and converted into an MV level electrical signal. The electrical signal is then converted into a digital signal by an AD circuit and processed by a chromatographic workstation on a microcomputer to complete the analysis and detection of trace amounts of organic sulfur compound tetrahydrothiophene.
Tetrahydrophene detection instrument
Product Name, Model, Specification, and Description
Gas chromatograph GC2020 FPD, capillary gasification chamber injection system
Chromatography workstation dual channel (computer, printer self equipped)
30 meter capillary column for chromatography
High purity hydrogen generator HK-3 hydrogen flow rate 300ml/min
High purity air generator AK-2 air flow rate 2000ml/min
High purity nitrogen cylinder 40L nitrogen flow rate 300ml/min
[Detection method for tetrahydrothiophene]
Tetrahydrophene detector for natural gasThe TM-5 capillary chromatography column and FPD flame photometric detector can be used to detect trace organic sulfur compounds - tetrahydrothiophene (THT) added to natural gas, and the natural gas components do not interfere with the determination.
1. Standard configuration:
Take 9.5153g of n-hexane and add 0.1105g of tetrahydrothiophene. The concentration of this solution is 7.7mg/mL.
Take 5uL of the above solution and add 2mL of n-hexane. The concentration of the solution is 19.25ug/mL
Tetrahydrophene in the air: Take 100mL of air and add 0.5uL of 7.7mg/mL concentration standard sample. Heat at 40 ℃ for 30 minutes and mix well, with a concentration of 38.5ng/mL.
Add tetrahydrothiophene to natural gas: Mix 1mL of natural gas with 1mL of tetrahydrothiophene in air
2. Analysis conditions:
<1> Instrument: Zhongkepu GC-2020 gas chromatograph
<2> Chromatographic column: TM-5
<3> Detector: FPD (flame photometric detector)
<4> Injection volume: 0.1uL

After sales service for tetrahydrothiophene detection
Warranty period: The instrument is guaranteed for 12 months from the date of self installation, debugging, and acceptance, with lifelong maintenance.
After the instrument malfunctions, timely response or guidance for maintenance can be provided, and professional technical service engineers can be dispatched to the site within 48 hours to troubleshoot.
If there is a software upgrade for the same series of instruments, our company will provide users with free upgrade services.
Installation and Debugging: After the user has prepared all installation conditions and requested installation, our company will send professional engineers to install and debug the instrument for free, and provide centralized on-site training on usage, maintenance, and upkeep for the user's personnel, until the user can operate and use the instrument proficiently and independently.
The auxiliary materials, spare parts, signal lines, power lines, etc. required for installation and debugging are provided free of charge by our company