A feasibility study for utilizing waste heat to generate electrical power using organic Rankine cycle (ORC)

Alexandria National Refining and Petrochemicals Company (ANRPC) is a refinery in Alexandria, Egypt.
A considerable amount of heat is wasted from the steam system after being utilized by different processes within the
refinery. The utilized steam which can be recovered has an average flow rate of 15 Ton/hour, an average pressure of
4.5 bar, and an average temperature of 180°C~220°C. The company decides to conduct a cost-benefit analysis to
assess the feasibility of a proposed Organic Rankine Cycle (ORC) system to convert this waste heat into electric
power. The approach used in this study is mainly an industry perspective. It deals with the ORC unit as an
investment opportunity, with its associated cost and benefits rather than its thermodynamic performance, which was
discussed in several previous papers. The most two important questions to be answered are: what is the total cost of
the ORC system (including the unit price, transportation, customs, installation, integration with the process,
commissioning, and startup), and what are the financial benefits of the project (including the yearly energy saving,
the decrease in the peak load, and the corresponding carbon dioxide (CO2) emission reduction). This paper aims to
be a guide for the decision-makers in the industry to support their decisions concerning the feasibility of installing
ORC systems to recover waste heat and convert it into power. Based on the heat content of the waste heat stream
and the efficiency of the evaporator (heat exchanger) of the working organic fluid, we can calculate the power that
could be generated from the turbine (expander), and based on the efficiency of the generator, we can calculate the
electrical power that can be generated (recovered) from the waste heat. In our case study, the expected generated
electric power is 1,750 kW or equivalently, 15,000,000 kWh of electrical energy annually. Financial analysis shows
that the ORC system, including the cost of the unit plus the costs of installation and integration into the process, will
cost approximately 4.8 Million USD. The payback period is 4 years. The ORC unit will reduce the CO2 emissions as
a result of not generating this amount of energy using traditional methods by approximately 7,500 Ton annually. The
ORC technology is an attractive solution for industries seeking for utilizing their waste heat to generate power,
hence, decreasing their energy bills and contributing to reducing CO2 emissions and combating global warming and
climate change.