Sulfur Recovery

The Claus sulfur recovery unit (SRU) and tail gas treating unit (TGTU) require a suite of process gas analyzers to ensure safe operation, high efficiency, and meet environmental regulations.

The development of sulfur recovery processes for oil refining, gas processing and coke oven plants began as a need to meet environmental regulations and has grown to become a major source of industrial sulfur.

Tail gas analysis of hydrogen sulfide (H2S) and sulfur dioxide (SO2) is a critical measurement used by every SRU. Feed gas analysis is also becoming more prevalent to mitigate hydrocarbon upsets and quantify acid gas contaminants.

With extensive experience in the sulfur recovery process, we provide high-quality analytical solutions across the SRU and TGTU, delivering the measurements needed to ensure efficient sulfur recovery operations.


  • Application +


    Continuous emissions monitoring (CEM Systems)

    CEM analysis on either cold-dry or hot-wet basis can ensure compliance with environmental regulations for SO2 emissions and can also provide a process optimization tool.

    Recommended products: 909, 910, 919, 920, 9900RM 

    Feed forward

    For SRU feed forward control, a full-composition, real-time analyzer is required for measuring all oxygen-consuming species in acid gas streams. This allows the exact amount of air to be added or removed from the reaction furnace for steady state control.

    Recommended products: IPS-4

    Sulfur pit safety monitoring

    In many SRUs, sulfur is stored in liquid form in sulfur pits, presenting a potential danger to personnel and plant safety. Monitoring H2S in the vapor space of these pits is of critical importance.

    Recommended products: 930, 888

    Tail gas air demand

    Measuring H2S and SO2 in the SRU tail gas supports feedback control (trim air control) of the air to acid gas ratio. It is the primary online analytical measurement used in the Claus sulfur recovery process.

    Recommended products: 900, 888

    Tail gas treating unit (TGTU)

    In the TGTU, it is important to measure residual hydrogen (H2) at the outlet of the reduction reactor, as well as the SO2 at the inlet of the quench tower.

    Recommended products: 931, 932, 934 

    Tail gas treating unit (TGTU) efficiency

    After cooling and quenching the off-gas from the reduction reactor, H2S is selectively absorbed by an amine solvent. Efficiency monitoring requires H2 and H2S measurements at the absorber outlet. COS can also be measured as an early sign of catalyst aging.

    Recommended products: 933, 934