My problem is how to start handling this problem. Do i need to consider residue as a flue? Dear engineers out there, really needs your help! Thanks!
draw a picture of the boiler. Draw lines showing fuels, air, Electric lines exhaust, Steam and whatever is attached to the boiler. draw a circle around the system. Every line that takes stuff in or out must be total on an energy and mas balance.
You will need to determine the steam pressure to be generated and from that you will know the steam saturation temperature. You will need to know if the stream will also be superheated. The availability of the fuel will determine the steam generation rate. You will need the heating value of those residues ( or of the various residues) and the available, sustained feed rate of the residues to determine the heat rate available to the boiler processes. Based on the chemical composition of the residue you will need to calculate the combustion air flow rate and add about 20%. Some of the available combustion heat will be lost through the boiler insulation. Considerable heat will be exit through the hot exhaust stack and some will be lost in the discharged ash. Some of the heat in the hot exhaust gasses can be used to preheat the combustion air and some to preheat the boiler feed water. The exhaust gasses must not drop below around 350F to prevent condensation of corrosive acids coming from sulfur compounds in the fuel so the amount of exhaust heat recovery is limited. Then the balance will be available to heat the steam. Associated with the generation of steam will be the power required for boiler feed water pumps and the induced draft and any forced draft fans. These may be either electrically or steam turbine driven. There will be an auxiliary condensate return system and a boiler make-up feed water supply and treatment system. There will be electric drivers for the conveying , preparation and injection of the fuel supply and for ash removal.
