Many industries face the problem of handling process vent gases containing VOCs and HAPs without causing any environmental damage.  We are of course, talking only about process vent gases and not petroleum flaring, gases in mining, etc.

Process vent refers to a vent gas stream that is discharged from a single or multiple units of operations in the same batch process train. These are manifolded together into a common plenum.  A process vent begins at the inlet to the control device prior to mixing with vent gas streams from other process trains or unrelated operations or at the point of discharge to the atmosphere.  It does not refer to exhaust streams from exhaust hood and ventilation fans that are used to provide ventilation for workers.

In a chemical process or painting and printing process or storage of chemicals, coating and laminating, there is the presence of Volatile Organic Compounds and Hazardous Air Pollutants.  VOCs and HAPs can have a detrimental effect on the human body.  The impact those industries producing these vent gases such as paint manufacturing can have a very damaging effect on our health.  Some of the negative effects associated with increased exposure to these gases include, but are not limited to increased risk of cancer, damage to the immune system, reduced fertility, neurological problems, respiratory conditions, etc.

Thermal oxidizers are an ideal option for the treatment of these vent gases.  These use elevated temperatures to destroy VOCs and HAPs, breaking them down into harmless by-products before releasing them into the atmosphere.

Thermal oxidation is a destructive technology for VOC/HAP purification that achieves high temperature due to thermal combustion of gases utilising their own high calorific values in the combustion chamber using multiple ceramic honeycomb beds as a heat exchanger to pre-heat the incoming air with the purified exhaust air or oxidise the outgoing air with a hot ceramic bed.

There are two options again in choosing the desired treatment system. There is a straight forward Direct Fired Thermal Oxidiser (DFTO) and then there is the Regenerative Thermal Oxidiser (RTO).

While the DFTO is preferred when the vent gas contains a high amount of VOCs, the RTO is preferred when the VOC content in the gas is below the LEL, requiring very little fuel intervention to get the system going on a continuous basis.

Haat has supplied quite a number of DFTOs and RTOs to many industries in India and abroad and these are running for many years.

Many of these systems are required to run continuously as the manufacturing plants themselves are running 24 x 7.  This shows the efficacy of the system for continuous operation over a long period of time.

The most important point is the thermal oxidation process ensures complete destruction of the VOCs and HAPs and releases breathable air to the atmosphere, thus ensuring safety to the workers and people around the plant.

A clean environment is Haat’s motto.