The present invention envisages a cool flame reactor assembly(100). The assembly(100) comprises a nozzle tube(1), a diluent tube and a reactor tube. The nozzle tube(1) is configured to receive fuel and to spray the received fuel through a tip of a nozzle of the nozzle tube(1). The diluent tube is configured to receive pre-heated diluents. The reactor tube has an electrical heating element(50) wrapped along the circumference of the reactor tube. The reactor tube is further configured to couple with the nozzle tube(1) and the diluent tube, to receive the sprayed fuel and the pre-heated diluents. The reactor tube comprises a vaporization zone(5), mixing zone(8) and an exhaust gas outlet(9). The reactor tube facilitates proper mixing and increased residence time to resultant mixture inside the reactor tube. The exhaust gas outlet(9) is configured to release the resultant mixture from the reactor tube.