What is Retrofit Emission Control Devices (RECD)? How its Work

Retrofit Emission Control Devices (RECD) reduce harmful emissions from existing diesel engines, such as those in Diesel Generators (DG) sets, by adding an add-on or after-treatment technology. Environmental regulations are becoming increasingly strict, but these devices do not require the whole engine or equipment to be replaced. RECDs work by capturing, filtering, or converting pollutants in the exhaust gases before they are released into the atmosphere.

How RECD Work

The operation of an RECD depends on the specific type of technology used. Here are some common types of RECDs and how they function:


1. Diesel Particulate Filters (DPF)

Function:

The DPF collects and removes particulate matter (PM), such as soot and ash, from exhaust gases.

Working Mechanism:

  1. Particulate matter is trapped in exhaust gases as they pass through ceramic or metallic filters.
  2. Over time, the filter collects PM, and when it reaches a certain level, the filter is either cleaned through a process called regeneration (burning off the soot) or replaced.
  3. The process of regeneration can be passive (occurring during normal operation) or active (triggered by an external process such as injecting fuel to raise the temperature).


2. Selective Catalytic Reduction (SCR)

Function:

The SCR system reduces nitrogen oxides (NOx) emissions by converting them into harmless nitrogen and water (H2O).

Working Mechanism:

  1. An SCR system injects a urea-based solution (commonly known as Diesel Exhaust Fluid, or DEF) into the exhaust stream.
  2. An exhaust gas catalyst reduces NOx to nitrogen and water as a result of a chemical reaction between the exhaust gases and DEF.
  3. The clean gases are then released into the atmosphere.


3. Diesel Oxidation Catalysts (DOC)

Function:

A DOC is a device that reduces the emissions of carbon monoxide (CO), hydrocarbons (HC), and some particulates.

Working Mechanism:

  1. The exhaust gases pass through a catalyst-coated surface (usually platinum or palladium).
  2. A catalyst facilitates the oxidation of CO and HC into water and carbon dioxide (CO2).
  3. The remaining exhaust gases are then expelled with lower levels of pollutants.


4. Exhaust Gas Recirculation (EGR) Systems

Function:

Using EGR systems reduces NOx emissions by lowering engine combustion temperatures.

Working Mechanism:

  1. A portion of the exhaust gas is recirculated back into the engine’s intake air.
  2. Oxygen is diluted in the combustion chamber, reducing the combustion temperature and, consequently, NOx formation.
  3. The reduced NOx levels lead to cleaner exhaust emissions.


Key Features and Considerations

Installation:

A RECD is usually installed in the exhaust system of a DG set. Depending on the type of device and existing engine design, the installation process varies.

Maintenance:

To maintain the effectiveness of the RECD, regular maintenance is required. It may be necessary to clean or replace filters, and DEF must be regularly refilled in SCR systems.

Compatibility:

It is essential to ensure that the RECD is compatible with the specific DG set and meets the required emission standards.

Performance Impact:

RECD reduce emissions effectively, but they may have a slight impact on engine performance, such as a small increase in back pressure.

Retrofitting existing DG sets with emission control devices can reduce harmful emissions, helping operators meet regulatory requirements and contributing to a cleaner environment.

Contact Creative Diesel Services Pvt Ltd to get Retrofit Emission Control Device (RECD) installed at your place!