DSI is relatively simple and versatile flue gas treatment process. It is based on the dry injection of one or more sorbents into the flue gas before a filtering unit, usually a bag filter, or an electrostatic precipitator. The sorbent reacts with the pollutants in a single pass. DSI allows the simultaneous removal of acidic gas components with calcium hydroxide Ca(OH)2 for example, and micropollutants.
The reaction between the gas-phase pollutants and the sorbent occurs in the reactor or flue gas duct and continues in the filter, especially with a bag filter. The reaction products and fly ash from the process are captured by downstream filtering equipment.
This process is considered to be ideally suited to low-capacity incinerators. It can easily be incorporated into existing installations and offers the following advantages:
- low investment cost
- simplicity of design and operation
- extreme space efficiency
- easy to automate
- low consumption of compressed air, electricity and water
- flexible operation in terms of temperature and capacity.
In addition, the purification process by-product is a dry powder which is easy to handle. To minimize the quantity of secondary products yielded, Lhoist has developed highly reactive hydrated limes (Sorbacal® SP, Sorbacal® SPS, Sorbacal® H, and so on) that make dry processing a very competitive solution for a growing number of applications.
DSI with Sorbacal® products has been demonstrated to be capable of achieving very high removal efficiency (up to >95% for SO2 and >99% for SO3, HF and HCI).
