CONTROLLED OXIDATION SOLUTIONS FOR THE CONTINUOUS TREATMENT OF EMISSIONS, VOCs, BTEX AND PROCESS WASTE GASES
Direct thermal oxidisers — also known as DFTOs (direct-fired thermal oxidisers), gas incinerators or afterburners — are devices designed to destroy pollutants through direct thermal oxidation in a controlled combustion chamber.
They are used to treat waste gas and liquid streams when the process needs to comply with emission limits or achieve high thermal destruction efficiencies.
At PREMATECNICA, we design and supply direct thermal oxidisers tailored to the specific conditions of each installation: pollutants present, flow rate, composition, inlet temperature, emissions requirements, integration with auxiliary equipment and continuous operation requirements.
WHEN TO CHOOSE A DIRECT THERMAL OXIDISER
A direct thermal oxidiser or incinerator is particularly suitable when the plant needs to treat continuous or semi-continuous emissions to a higher standard than that achievable with open combustion.
In the case of a flare, its primary function is not to ensure safety in the event of relief operations or emergencies, but rather to treat emissions in a controlled manner within a chamber where combustion can be controlled more precisely.
Whereas in a recuperative oxidiser some of the heat from the exhaust gases is reused via a heat exchanger to preheat the inlet stream, in a direct thermal oxidiser the contaminated gases are burned without utilising the heat generated to preheat the inlet stream.
DFTOs are therefore particularly useful for discharges containing gases with a high calorific value that do not require additional feed gas, as well as discharges of waste gases or dirty, viscous or highly corrosive liquids that could degrade or block the heat exchanger.
OPERATION AND SETTINGS
The operation of a DFTO relies on four key variables: temperature, residence time, mixing or turbulence, and available oxygen. Effective oxidation depends not only on reaching a high temperature, but also on the balance between these four factors, which enable the complete destruction of pollutants and minimise the formation of products of incomplete combustion.
Within this family, two main configurations can be distinguished. The first is the DFTO, or horizontal forced-draught thermal oxidiser, which is usually configured horizontally and is particularly suitable when downstream equipment that generates backpressure needs to be integrated, such as additional environmental control systems including DeNOx, DeSOx, scrubbers, filters, etc.
The second is the DFTO, or vertical natural-draught oxidiser, designed primarily for the treatment of waste gases, with a more compact design and the option of integrating a chimney and a sampling point within a single solution.
MAIN COMPONENTS
The combustion chamber is the heart of the system and determines the thermal behaviour and overall stability of the equipment. Installed in the combustion chamber, the burner system designed by Prematécnica ensures safe, uniform and efficient combustion. Refractory insulation, whether made of brick, concrete or ceramic fibre, must be carefully selected to withstand the operating conditions and the fluids to be oxidised, whilst the overall design and control system of the equipment must be adapted to the type of feedstock and its variability, and may incorporate systems to optimise auxiliary gas consumption, such as high-temperature oxygen probes for maximum efficiency and advanced Burner Management Systems (BMS) to ensure process safety.
PREMATECNICA DESIGNS AND IMPLEMENTS YOUR DIRECT THERMAL OXIDISER
Each direct thermal oxidiser requires a specific design basis. At PREMATECNICA, we analyse the actual process conditions: contaminants present, flow rate, composition, variability, inlet temperature, destruction target, downstream treatment process, energy integration, and factors affecting installation and maintenance.
Building on that basis, we help to determine the most suitable configuration — horizontal forced draught or vertical natural draught — and how it can be integrated with the rest of the plant. In addition, we optimise the combustion chamber and the burner system using CFD (Computational Fluid Dynamics) to maximise combustion efficiency and the durability of the refractory insulation.
Our approach combines process engineering, industrial combustion and the integration of auxiliary equipment, including DeNOx systems, scrubbers, control systems, installation supervision, commissioning and after-sales support.
