Volume No. 11 Issue No.: 3 Page No.: 558-562 January-March 2017
FEED FORWARD CONTROL METHOD TO REDUCE SOOT FROM STEAM ASSISTED FLARES
Srinivasa Rao R.* and Murali Krishna K. V. S. G.
Department of Civil Engineering, JNTU Kakinada, Andhra Pradesh (INDIA)
Received on : December 16, 2016
Flaring is an oxidation process used in process industries like oil and gas industry to burn unwanted and excess waste gases. In this process, black smoke and particulate matter results from the flare stacks. Smoke formation may vary from different gases which are flaring have different carbon components. Rich in hydrocarbon molecular weight and unsaturated hydrocarbons are more favourable for smoke generation. Smoke formation depends on distribution of combustion air mixed in the flare tip nozzles. Most of the flare stacks are assisted with steam to get complete combustion to avoid black smoke and unburnt hydrocarbons. The amount of steam is insufficient to the flare stack, leads to generate more smoke. It was estimated that, soot particles life time in the atmosphere is 1-2 weeks to disperse. Recently lot of respiratory diseases are reporting more and are caused by air borne particles such as soot in the air. The size of a particulate matter plays major role on severity of lung damage. Less than 3micron size fine particles are more prone to pass through the lung tissues. The short lived climate forcers such as black carbon particles play significant role in global warming. Reduction in methane and black carbon particles achieve reduction in global warming. The new approach of automation of steam control to the flare stack by adopting steam to hydrocarbon ratio control and feed forward action to minimize the time lag from the Gas Chromatograph result, will gives the smokeless operation of flare stacks in oil and gas industry. This paper explains the methodology of control of soot from flares by S/C ratio control and how the combustion efficiency varies with the amount of steam. The economical benefit of smokeless operation of flare stacks are energy saving in terms of minimization of excess steam and indirectly reduce the amount of CO2 to the atmosphere.
Keywords : Automatic control, Black carbon, Poly aromatic hydrocarbons, Soot