What to understand about Thermal Desorption

1. What to understand about Thermal Desorption? Thermal Desorption is one of the physical separation procedures, contaminated soils are simply heated to volatilize organic and water contaminants. A carrier gas or even vacuum system transports volatilized water as well as organics to the gas treatment system. There are usually three methods of thermal desorption: •Indirect heated An outwardly fired rotary dryer volatilizes the water as well as organics from a contaminated media into the inert carrier gas stream; steam can also be utilized as an indirect heating method. •Indirect fired The straight direct-fired rotary dryer heats the air stream that is in contact with the contaminated soil. •Direct fired Fire gets applied directly upon the surface of contaminated media. Thermal desorption procedures can be separated into two groups: Low temperature thermal desorption (LTTD) In LTTD, soils get heated to between 90°C and 320°C, this particular system gets utilized for VOC and petroleum removal. Remediated soil retains the majority of the physical properties until and unless it has gotten heated at the higher end of the temperature range though plenty of soils can be detrimentally affected. High temperature thermal desorption (HTTD) There is another group, which is called HTTD. These soils are heated to almost 320°C to 960°C. This particular system gets used for the higher chain hydrocarbons, pesticides etc. HTTD systems are often combined with solidification/stabilization and incineration treatments. Soils are rarely re-useable without important geotechnical improvement.

2. Plant Description Excavated soils need the soil processing before thermal treatment. One of the very common Thermal Desorption design is the rotary dryer. These rotary dryers are direct-fired or indirect horizontal cylinders. The cylinder is mainly inclined and rotated to move the contaminated soil along the cylinder. All Thermal Desorption systems also produce gas that needs the treatment for removing water vapor, particulates and contaminants. You can easily remove the particulates by equipment such as wet scrubbers or filters. Contaminants can be incinerated in a second combustion chamber or removed through condensation and then it gets activated carbon adsorption units. Common equipment utilized in thermal desorption: •Rotary kiln •Particulate filters •Control systems •Soil processing equipment •Granular activated carbon pods (gas treatment) •Fuel storage for rotary kiln •Dewatering unit