OXIDIZERS
Donau Carbon Technologies SRL experience in construction of all combustor types in different production fields (printing, flexible packaging production, tapes, rubber, chemicals, waste treatment, deodorisation, production of biofuel and construction material) is worldwide valued.
Every component is designed, purchased and checked over to reduce maintenance intervention, and relevant plant out of services, both ordinary and extraordinary.
Trough remote plant supervision, performed by our technical department from the headquarters in Guanzate, Donau Carbon Technologies SRL offers to its Customers Maintenance Repair and Overhaul contracts distinguished by a high-value and specialized personnel.
REGENERATIVE THERMAL OXIDIZERS (RTO)
Regenerative thermal oxidation allows solvent oxidation by increasing the polluted air temperature over 750-800 °C with a high efficiency heat recovery system using ceramic material.
Starting from 1995 till today, Donau Carbon Technologies Srl, with more than 200 combustors of this type having capacities between 3.000 and 330.000 Nm3/h, achieved very high quality and reliability levels. Therefore actually Donau Carbon’s products represent the State of the Art.
Donau Carbon Technologies Srl fulfils markets requirements by offering regenerative combustors also for particular applications, like treatment of CO streams produced by industrial processes, treatment of odors and treatment of flue gases coming from waste processing.
The regenerative thermal oxidation plant is usually composed by 3 towers: in presence of high air flowrate it could be realized also with 5 towers.
Donau Carbon Technologies Srl offers these two solutions, depending from the necessities.
Each regenerative chamber contains a ceramic matrix which, depending on the direction of flow, absorbs heat from the waste gas after combustion or preheats the air prior to combustion.
The exhaust solvent laden air (SLA) coming from the production is conveyed by a fan through the ceramic bed in chamber 1, and after pollutant oxidation it flows out through chamber 2 ceramic bed.
While the ceramic material of chamber 1 cools up and the one of the chamber 2 heats up, chamber 3 is cleaned and the residual of the previous cycle is delivered to plant inlet.
After a defined time the flow inversion arrives: chamber 1 is now cool and is cleaned, chamber 2, heated up by the flow coming out from the combustion chamber is crossed by the incoming flow, this goes out by chamber 3 after oxidation.
The average cycle time varies from 60 to 120 seconds depending on the nature and concentration of the individual contaminants.
Combustion temperature is normally set at 800°C and auto produced by the heat from the oxidation of the VOC’s, or, if the VOC concentration is low, by addition of support fuel.
In case of high pollutant concentrations, there is residual heat into the flue gases, recuperative heat exchanger can be installed to produce steam or to heat up diathermal oil, with energy saving.
CATALYTIC THERMAL OXIDIZER (CTO)
Catalytic oxidation is a process to treat waste air or gases.
Usually traditional oxidation processes are running at temperatures higher than 750°C. In case a few organic compounds are present in the gas stream, to keep these temperatures, the incineration process needs a huge quantity of additional fuel.
With the catalytic oxidation the additional fuel can be saved by means of a special catalyst that makes possible the oxidation of organic compounds at lower temperatures (for example from 250°C to 350°C).
The process is very simple. The waste air or gas is sucked by a fan, the stream passes through a heat exchanger which heat up it and then feed into the catalytic reaction chamber. The pre-heating is done by the hot stream (cleaned gas), in outlet from reaction chamber, passing on the other side of the exchanger; in this way it is cooled down before sending it through the stack.
A start up burner ensures that the gas stream has the right oxidation temperature before getting in contact with the catalyst. There, the organic compounds reacts, producing CO2 and H2O and heating up the gas and the catalyst.
If the concentration is high enough, the process autothermal, i.e. no consumption support fuel.
Heart of the process is the catalyst. If the composition of gas is known and it hasn’t changes during the years, the catalyst can work for more than 5 years.
Limit of this process is the presence in the stream of compounds that can damage the operation of catalyst, as for example dust, silicon and similar substances.
If the concentration of organic compounds is too high, the temperature exceed the project value and it is necessary to cool down the stream going to the catalyst; this can be done by water or fresh air injection or avoiding the preheating of the stream through the heat exchanger.
THERMAL RECUPERATIVE OXIDIZERS (TRO)
The recuperative thermal oxidation allows the air depuration by thermal oxidation at 750-800°C. The thermal recovery is done by means of an air-air heat exchanger.
The polluted stream is driven to the heat exchanger by a fan, where it is pre-heated thanks to the heat contained in the depurated stream.
Then the polluted stream enters the oxidation chamber whose shape and dimensions are designed in such a way to ensure the uniform temperature and heat distribution. Here the oxidation process happens.
The burner provides the needed heat to obtain the rapid and complete combustion of pollutants, in turbulent conditions with low NOx production.
The purified flow coming out from the combustion chamber, before entering in the polluted air preheating exchanger, passes through a recovery boiler where the thermal oil used in production is heated.
