Optimasi siklus termodinamika integrasi boiler AQC dan PH pada desain WHRPG di industri semen

Abstract

The cement industry is a chemical industry that requires large amounts of energy and releases CO₂ emissions, one of which is produced from limestone calcination. Electricity consumption index for 2017 at PT Holcim Indonesia Tbk. Cilacap Plant averaged 92.20 kWh / ton cement and 3,352MJ / ton clinker in thermal form. This shows that the use of thermal energy is very dominant in the production process. The opportunity to reduce the index of electricity consumption is a very appropriate step in order to reduce greenhouse gas (GHG) emissions and production costs, thereby increasing its competitiveness. Installation of WHRPG system in the preheater (PH) process output unit and the water quenching cooler (AQC) output to utilize exhaust heat that can produce pressurized steam and when combined with the steam turbine starter drive and electric generator coupled, the system is able to generate electricity to supply the needs electrical energy industry. From the data of potential exhaust gases in PH and AQC and the design determination of the choice of operating conditions of the selected three-level steam turbine pressure, the optimization results are obtained by applying a graded nonlinear GRG model, the thermal efficiency of the WHRPG water system is optimal at 24.38% with work output the optimum thermal value is 6,420.29 kW and the estimated gross electric power yield is 6.089,51kW. The optimal conditions achieved are indicated by the pinch point value on the AQC boiler that occurs in the economizer at 10K while the PH boiler occurs at the superheater of 10K according to the specified pinch minimum constraints. If the estimated power of the balance of plant and auxiliaries in the WHRPG system is 12% and the cement production capacity is 7,800 tons / day assuming a WHRPG capacity factor of 73%, then the magnitude of the reduction in electrical energy intensity is at least 12.04 kWh / ton cement.

Keyword : Preheater, Air Quenching Cooler, WHRPG, HRSG, Cement, GRG nonlinear, Optimamization, Kawasaki