H2S Scavenger Dosing Guide — Calculations, Injection Methods & Field Optimisation

MEA Triazine reacts with H2S at a theoretical stoichiometry of 1 mole triazine to 3 moles H2S. At 78% active content and 1.08 kg/L density, the theoretical minimum consumption is approximately 2.6 litres of MEA Triazine 78% per kilogram of H2S removed. In field conditions, expect practical consumption of 3.2–5.0 L/kg H2S in well-designed systems with good gas-liquid contact, and 5–10 L/kg in less favourable conditions such as direct pipeline injection without a contact vessel. The key variables that affect dosing efficiency are: H2S concentration and mass loading, gas or liquid flow rate, system temperature, contact time and mixing quality, water availability in the system, and competing reactions with CO2 or organic acids.

Step 1 — Determine H2S mass load: Calculate the total mass of H2S entering your system per hour. For gas systems: H2S load (kg/hr) = gas flow rate (Nm³/hr) × H2S concentration (mg/Nm³) ÷ 1,000,000. For liquid systems: H2S load (kg/hr) = liquid flow rate (m³/hr) × H2S concentration (mg/L) ÷ 1,000. Step 2 — Select a consumption factor: Use 3.2 L/kg for contact tower systems with good mixing. Use 4.5 L/kg for inline injection with a static mixer. Use 6–8 L/kg for direct pipeline injection without a mixer. Use 8–10 L/kg for batch treatment of tanks or low-contact systems. Step 3 — Calculate hourly dosing rate: Dose rate (L/hr) = H2S load (kg/hr) × consumption factor (L/kg). Step 4 — Size the dosing pump: Select a chemical metering pump rated for at least 1.5x the calculated dose rate to allow for turndown and H2S variability. Ensure the pump materials are compatible with MEA Triazine (stainless steel or PTFE wetted parts recommended).

Contact towers deliver the best chemical efficiency because they maximise gas-liquid contact time and surface area. A well-designed contact tower can achieve near-stoichiometric consumption (2.6–3.5 L/kg). Tower sizing guidelines: Minimum gas residence time of 15–30 seconds in the packed section. Liquid circulation rate sufficient to keep packing wetted — typically 2–5 L/min/m² of tower cross-section. Packing height of 1.5–3 metres depending on H2S loading and target outlet specification. For inline injection (no tower), install a static mixer downstream of the injection point to improve dispersion. Minimum pipe length of 10–15 pipe diameters after the mixer is recommended for adequate reaction time. Injection quills should be oriented to spray into the gas or liquid flow, not against the pipe wall.

Effective field optimisation requires regular monitoring of inlet and outlet H2S concentrations, chemical consumption rates, and system operating conditions. Key monitoring points: Measure H2S at the inlet and outlet of the treatment system. Track litres of MEA Triazine consumed per kilogram of H2S removed — this is your primary efficiency metric. Log operating temperature, flow rate, and any changes in H2S loading. Optimisation actions: If consumption is above expected range, check for poor mixing, low temperature, or competing reactions. If outlet H2S is consistently well below target, reduce the dose rate — you may be over-treating. If you observe solids formation, reduce the dose rate and check temperature (solids risk increases below 15 °C and with overdosing). Our technical team provides dosing optimisation support for customers purchasing MEA Triazine 78% from Vasudev Chemo Pharma.

Application type — Consumption factor — Typical dose range: Contact tower (gas treating): 3.0–3.5 L/kg H2S — 50–500 L/hr depending on gas volume Inline injection with static mixer: 4.0–5.0 L/kg H2S — 20–200 L/hr Direct pipeline injection: 6.0–8.0 L/kg H2S — 10–150 L/hr Batch tank treatment: 8.0–10.0 L/kg H2S — volume-based calculation Produced water treatment: 5.0–7.0 L/kg H2S — proportional to water flow These are starting estimates. Actual consumption should be verified in the field and optimised based on monitoring data. Vasudev Chemo Pharma's technical team can assist with site-specific dosing calculations.