CO/H₂ trim control

CO/H₂ trim control is a software module in the LAMTEC CMS, BT300, ETAMATIC, ETAMATIC OEM, FMS and VMS combustion management systems. Working with the LT3-F lambda transmitter and the KS1D combination probe, it optimises the fuel-air ratio automatically by moving again and again towards the emission edge, where complete combustion turns into incomplete combustion. At this point emissions and fuel consumption are at their lowest and combustion efficiency at its highest. For natural gas and light fuel oil EL applications, the system is SIL2 fail-safe.

O₂ control relies on measuring the oxygen left in the flue gas, but oxygen alone does not reveal whether combustion is complete, and influences such as false air can distort that reading. When combustion is incomplete, carbon monoxide and hydrogen always appear together. The KS1D probe, made of zirconium dioxide ceramic, measures O₂ and COe — the sum of unburnt components such as CO, H₂ and CxHy — directly and simultaneously in the flue gas. As soon as the probe detects unburnt CO/H₂, the working point is shifted towards a higher lambda, meaning more air and less fuel.

Because the cycle of searching, adjusting, holding and monitoring repeats continuously, the optimum working point is maintained even under unfavourable weather and plant conditions. According to LAMTEC's system overview, the O₂ content of the flue gas can be lowered markedly further than with O₂ trim control, which corresponds to roughly 0.5–2 % higher combustion efficiency and a matching drop in fuel consumption. The O₂ value measured at the same time is not used for the control itself but for monitoring and visualisation, and it acts as a safety function: if O₂ falls below a defined threshold, CO control can be switched off.