Triazine-Based H2S Scavenger: Complete Guide to Sour Gas Treatment

What Is a Triazine-Based H2S Scavenger?

A triazine-based H2S scavenger is a water-soluble liquid chemical that removes hydrogen sulfide (H2S) from gas and liquid streams by reacting with it irreversibly to form non-volatile, water-soluble by-products. The most widely used grade is MEA Triazine 78% — chemically 1,3,5-tri(2-hydroxyethyl)-hexahydro-s-triazine, CAS number 4719-04-4 — a clear to pale-yellow liquid produced by reacting formaldehyde with monoethanolamine (MEA). In plain terms: you inject the scavenger into a sour stream, it locks up the H2S permanently, and the spent product leaves with the water phase. Because the reaction cannot reverse, the captured sulfide cannot re-release downstream. Triazine chemistry became the dominant H2S scavenging approach in the 1980s because it is simple to deploy, needs no regeneration column, and produces clean, disposable by-products. This guide is the pillar of our H2S scavenger knowledge base; each section links to a focused deep-dive on mechanism, dosage, applications, safety, and sourcing.

• MEA Triazine 78% (CAS 4719-04-4) — the industry-standard liquid H2S scavenger
• Irreversible reaction: H2S is locked into water-soluble dithiazine
• ~4.5 L of triazine per kg H2S removed, with a 1.5–3x field excess factor
• Used in oil & gas, refining, biogas, and landfill-gas desulfurisation
• Non-triazine EDDM available where amine pH shift must be avoided
• Direct-manufacturer supply with COA, TDS, and SDS documentation

How Does Triazine Scavenge H2S? (Mechanism in Brief)

The triazine molecule contains three nitrogen atoms in a six-membered ring. When hydrogen sulfide contacts the ring, sulfur progressively substitutes for nitrogen through nucleophilic attack. The first mole of H2S converts triazine into a thiadiazine intermediate; the second mole produces dithiazine, the dominant end product; and under H2S excess a third step can form trithiane. The released monoethanolamine and the dithiazine by-product are both water-soluble and compatible with standard produced-water disposal. Each mole of MEA triazine can theoretically capture up to two to three moles of H2S, though field efficiency is typically 60–80% of theoretical because contact time and mixing limit conversion. For the full reaction pathway and diagram, see our dedicated article on H2S scavenging chemistry linked below.

Where Are Triazine H2S Scavengers Used?

Triazine H2S scavengers are used across the entire oil and gas value chain and in adjacent industries. Upstream, they are injected at the wellhead and into gathering lines to protect pipelines from sulfide corrosion and to meet sales-gas H2S specifications. Midstream, they treat sour gas in bubble towers and spray contactors at gas-processing facilities. Downstream, refineries dose triazine into fuel-gas systems, sour-water headspaces, and crude storage tanks for vapor-phase H2S control. Beyond hydrocarbons, triazine scavengers remove H2S from biogas, landfill gas, and geothermal streams so the gas meets pipeline-injection or engine-fuel specifications. The chemistry is identical across these applications — only the injection point, contact method, and dose change with the H2S load and stream type.

Triazine H2S Scavenger Dosage — Quick Reference

As a planning figure only, MEA Triazine 78% is often cited as consuming on the order of 4.5 litres of product per kilogram of H2S removed at theoretical stoichiometry; the exact capacity for a given grade must be taken from the manufacturer's Technical Data Sheet (TDS) and Safety Data Sheet (SDS) rather than a generic value. In the field, operators commonly apply an excess factor of roughly 1.5x to 3x to account for imperfect gas-liquid contact, competing CO2, and short residence times, with the actual factor established from field trials and published sour-service practice (for example AMPP/NACE guidance). As an illustrative example, a stream carrying about 100 ppmv H2S at 1 MMSCFD may require on the order of tens to low-hundreds of litres of triazine per day, depending heavily on injection method and contact time. Direct injection into a flowing line is simplest but least efficient; a contact tower or static mixer typically improves utilisation and lowers chemical cost. Always confirm dosage with a bench titration on your actual fluid and against the product TDS, because pH, temperature, and hydrocarbon composition all shift real-world consumption. Our dosage guide covers the full calculation method.

Triazine vs Non-Triazine and Solid Scavengers

Triazine is not the only H2S scavenging chemistry, and responsible selection means matching the chemistry to the stream. Liquid triazines (MEA and MMA) generally offer the highest capacity per litre, fast ambient-temperature reaction, and clean water-soluble by-products — well suited to continuous injection and contact towers. Glyoxal-based scavengers are a non-triazine liquid option that avoids amine chemistry but commonly cost more (frequently reported in the region of 20–40% higher) and typically suit lower-H2S duties; the precise premium depends on current pricing and supply. Iron-oxide solid beds (iron sponge) capture H2S in a fixed bed but create spent-media disposal and shutdown requirements. Non-triazine formaldehyde-donor chemistries such as EDDM (CAS 3586-55-8) avoid amine pH shift and salt precipitation, which can help in high-scaling or catalyst-sensitive service. These are general tendencies; verify capacity, efficiency, cost, and compatibility for a specific product and stream against the manufacturer's TDS/SDS, recognized standards (e.g. AMPP/NACE), and bench data. There is no single best scavenger — there is a best fit for each stream, which is why the comparison articles linked below matter.

Sourcing Triazine H2S Scavengers Directly From the Manufacturer

Much of the triazine sold worldwide passes through oilfield-service bundles and regional distributors, each adding margin — end users can pay 30–60% more than ex-works manufacturing cost. Vasudev Chemo Pharma manufactures MEA Triazine 78% and non-triazine EDDM at an ISO 9001:2015 certified facility in Gujarat, India, close to Kandla, Mundra, and Hazira ports for efficient export. We supply operators, midstream companies, and distributors directly, with batch-level Certificates of Analysis, Technical Data Sheets, and SDS documentation, in 220-litre drums, 1000-litre IBCs, or bulk. For teams with predictable consumption, monthly or quarterly supply contracts give price stability and guaranteed availability. Free samples are available for laboratory qualification before committing to production volumes.