Cooling flue gas coming out of the secondary combustion chamber in an incinerator has always posed some serious questions.

- What is the best method?

- Which cooling media is better, air or water?

- How much temperature drop can be achieved?

- What configuration of downstream equipment is required?

- What is the MOC?

- Will this system work satisfactorily over a reasonable period of time?

- How to bring down initial and running costs?

These are just some of the questions that arise off the cuff. Many equations and configurations are being tried out by incinerator manufacturers all over the world for this purpose. Many solutions are also being considered. 

Equipment like Saturators and Gas coolers use water to bring down the temperature from 1100°C to around 200 to 300°C.  Then there are dilution chambers using air as the medium for cooling.

These equipment have their own advantages and disadvantages. Without going into the details of these, let us just agree on one point. The volume of these equipment is large, requiring use of considerable quantity of steel or stainless steel and refractory lining. In the process, the entire equipment cost shoots up.

To reduce costs and to make the system simpler, our Swiss partner suggested we use a new design of Ejector. Although the design of the ejector is a little complex, it is easy and inexpensive to make.

 The operating principle of the incinerator’s ejector is that the pressure energy in the motive fluid is converted to velocity by an adiabatic expansion in the converging/diverging portions. Due to the pressure drop of the motive fluid, it will create a low-pressure zone before the mixing chamber. Due to the low-pressure zone, the suction fluid will start to move to toward and mix with motive fluid in the mixing chamber. When the mixed fluid enters the diverging portion of the ejector, its velocity energy is converted into pressure energy. In the process the outgoing incinerator flue gas temperature is brought down very quickly.

We have now introduced this in our ADR model incinerators and many are under production. The fluid medium is air.

What advantages does the customer get?

- Low capital cost

- Low running cost

- Fast production

- Negative pressure in the incinerator chamber

- No leakage of flue gas

- Simpler and effective 

- Reduction in temp. from 1100° to 300 °C

- Practically no maintenance

Credit must also go to our Design and Production teams to smoothen out the design, test it practically on the job and satisfy themselves before standardizing on the design.

The incinerators on the shop floor with this new ejector are getting ready to go to Bangladesh, Maldives,  J & K, UAE and Gujarat.