What is Dry Sorbent Injection (DSI) process?

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. 

Lhoist product range dedicated to DSI

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).

  • Sorbacal® SPS
  • Sorbacal® Micro
  • Sorbacal® SP
  • Sorbacal® H
  • Sorbacal® A
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Dry Sorbent Injection