Fuji Oil Company, Ltd. (FOC) has been stepping up its energy conservation efforts. At its Sodegaura Refinery, FOC has expanded the scope of energy conservation activities to include other plants operating in the same petrochemical complex. FOC has been working on a technology that utilizes low-grade waste heat with temperatures of 150ºC or lower. Until recently the waste heat had been merely released into the atmosphere due to the lack of alternative options. The new technology has been implemented in phases at the Sodegaura Refinery and adjacent Sumitomo Chemical Chiba Works. It has already conserved huge amounts of energy by harnessing the surplus low-grade waste heat to generate electricity.
FOC received the 2006 Agency for Natural Resources and Energy Director-General's Award from the Japan Machinery Federation jointly with Sumitomo Chemical Co., Ltd., and Chiyoda Corporation for its proven energy-saving initiatives.
The multiplant low-exergy utilize system consists of the following two subsystems.
The multiplant energy sharing system is designed to recover waste heat generated from multiple plants for joint use of energy. The low-temperature waste heat that is released from FOC's processing plant at temperatures between 80ºC to 150ºC is used to heat water piped in from the adjacent Sumitomo Chemical plant's boiler to a temperature of 110ºC via a heat exchanger. The heated water is then supplied back to Sumitomo Chemical, saving the boiler fuel normally used for heating.
The system utilizes waste heat that had been previously released into the atmosphere or cooling water to now heat boiler water and save energy as the result.
Low-grade Heat Power Generation System
The low-grade heat power generation system utilizes heat (low-temperature waste heat at temperatures up to 115ºC) recovered from the top of the FOC plant‘s distillation column to generate high-pressure ammonia which then powers the electric power generation turbine. The system has been in operation since October 2006.
The system employs a newly installed heat exchanger to recover waste heat, which would have been released into the atmosphere if a conventional air-cooled heat exchanger were employed. This reduces the use of fossil fuel that would normally be used to generate power.
The system offers superior operational reliability and is the world's first power generation system that uses a heat exchanger to directly recover low-temperature waste heat from a large-scale processing plant located in a petrochemical complex.
These systems alone enabled to cut the annual crude oil consumption by 10,700 kiloliter. Since neither the energy sharing system nor the low-grade heat power generation system use additional fuel, CO2 emissions are reduced by 28,000 tons. These systems are making a big difference when it comes to saving energy and saving the environment.