Total Hydrocarbon Analyzer

What is the Total Hydrocarbon Analyzer?

A continuous flame ionization analyzer that reports total hydrocarbons as a methane-equivalent concentration. It is the right choice for emission limits, solvent recovery control and fugitive hydrocarbon monitoring on a single calibrated scale.

Overview

The total hydrocarbon analyzer burns a continuous sample stream in a hydrogen flame and measures the ions formed, giving a signal proportional to the carbon content of all organics present. Calibration with methane or propane sets the scale, and results are reported as methane equivalent. A heated sample line at 120 to 190 °C prevents heavy hydrocarbons and moisture from condensing before the detector. A catalytic or selective scrubber can be switched in to remove all hydrocarbons and provide an automatic zero, improving stability. Some configurations add a non-methane cutter, a small catalytic reactor that oxidizes non-methane species so methane can be measured separately. Ranges from 0 to 10 ppm up to percent levels cover ambient checks and process streams. Because response is broad, the instrument suits limits written as total hydrocarbon or total organic carbon in gas, and is widely used in solvent recovery, printing and coating operations.

How does it work?

VOC analyzers rely on different detection principles. A photoionization detector uses a sealed ultraviolet lamp, usually at 10.6 eV, to ionize molecules with an ionization potential below the lamp energy, and measures the resulting current; it reports total VOC without speciation. Flame ionization detectors burn organics in a hydrogen flame and measure the ions produced, giving total hydrocarbon response calibrated as methane or propane. Gas chromatography with FID first separates compounds on a column, producing speciated results. Proton transfer reaction mass spectrometry ionizes VOCs with hydronium ions and identifies them by mass, giving fast speciated data. Sorbent tube sampling collects VOCs on Tenax or charcoal and delivers them to the laboratory for thermal desorption and GC analysis.

What are the key features?

• Flame ionization gives a broad response to all organic compounds in the sample.
• Heated sample line prevents condensation of heavy hydrocarbons and moisture.
• Switchable scrubber provides automatic zero for improved baseline stability.
• Optional non-methane cutter separates methane from other hydrocarbons.
• Continuous output suits process interlocks and emission compliance alarms.
• Calibration as methane or propane keeps data comparable across instruments.

What are the technical specifications?

A typical total hydrocarbon analyzer configuration offers detection principle of Flame ionization detection, measurement range of 0–10 ppm to 0–100,000 ppm, lower detection limit of 0.05 ppm as methane, response time of < 2 s (T90), sample line temperature of 120–190 °C, heated and zero method of Catalytic scrubber, automatic. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Total Hydrocarbon Analyzer is used in solvent recovery unit control, printing and coating emission monitoring, fugitive hydrocarbon leak checks and landfill and biogas methane measurement. Across the wider VOC Analyzers class, laboratories also deploy it for industrial fence-line and leak monitoring, indoor air quality and building surveys and workplace exposure assessment.

Which standards and certifications apply?

Relevant standards and methods include US EPA Method TO-15, US EPA Method TO-17, ISO 16000-6, ISO 16017-1, EN 14662-3 and HJ 644. Certification candidates for this model are CE, ATEX or IECEx hazardous area options and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Calibrate photoionization detectors with the target gas where possible, because response factors differ widely between compounds, and check the lamp window for fouling. For GC systems, verify column performance with a standard mixture, check carrier gas purity and replace the FID jet or the mass spectrometer filament as needed. Sorbent tubes must be conditioned, capped, stored cool and analysed within the method holding time, with field and tube blanks included. For continuous fence-line monitoring, shelter the analyzer, condition the sample line to avoid condensation and provide suitable calibration gas delivery. Record detection limits, calibration dates and validity flags, and follow the applicable national method for reporting.

How do I select the right Total Hydrocarbon Analyzer?

Select this analyzer when a single total hydrocarbon or methane-equivalent limit governs the process and continuous output drives interlocks or alarms. When compound identity matters, use a GC system. In an RFQ, specify the range, calibration gas, sample temperature and pressure, response time and whether a non-methane cutter is required.

How does it compare with other VOC Analyzers variants?

Match the analyzer to the purpose. For leak detection, screening and rapid field checks, a portable photoionization detector is fast and easy, but it reports only total VOC and has compound-dependent response factors. For regulatory or speciated data, gas chromatography with FID or mass spectrometry is required, either online or in the laboratory after sorbent tube sampling. Total hydrocarbon analyzers suit continuous monitoring of hydrocarbon emissions against a single methane-equivalent limit. PTR-MS gives real-time speciated data for research on emission sources and reaction products. Consider the required detection limit, the target compound list, whether real-time or time-integrated data is needed, and the calibration gases and lamp or column consumables.