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Apr 11, 2017

Repairs Completed to Core Equipment at East Environment Center for Ariake Wide-Area Administrative Affairs Union

Hitachi Zosen Corporation recently completed repair work on the core equipment of the East Environment Center (EEC) for the Ariake Wide-Area Administrative Affairs Union. This is the first example of a panel boiler-type exhaust heat recovery power generation system for small-scale waste incineration plants.

■Outline of the core equipment repair work for the East Environment Center (waste treatment facility)
This work was done in order to extend the life of the EEC, which had been operating for more than 15 years since operation started back in April 1999 by the Ariake union. Repair work was started on the aging core equipment in December 2014. Waste incineration plants are generally considered to have an operational lifetime of twenty or thirty years, but repairs and additional construction after the first decade allow this period to be extended.

1. Client:          Ariake Wide-Area Administrative Affairs Union
2. Project:        Core equipment repair work for the East Environment Center (waste treatment facility)
3. Description:  Before repairs: Stoker-type waste incinerator; 70 t/day (35 t/16 h x 2 units) (water-injected type)
                            After repairs: Stoker-type waste incinerator; 98 t/day (49 t/24 h x 2 units) (boiler type)
4. Location:      386 Oaza Konoha, Gyokuto-machi, Tamana-gun, Kumamoto

■Main improvements from the work
1. Introduction of a panel boiler-type exhaust heat recovery power generation system for small-scale waste incineration plants
The EEC was originally designed without power generation equipment. However, these repairs added a panel boiler®, steam turbine power generator, and other power generation equipment to allow it to generate electricity. This system, the panel boiler-type exhaust heat recovery power generation system for small-scale waste incineration plants, was awarded the President’s Award from the Japan Machinery Foundation at the 37th Energy-Efficient Machinery Awards, held by the Japan Machinery Foundation last month, and was first installed by Hitachi Zosen in this project.
2. Extension of operating hours
This work resulted in improved automatic operation, allowing a change from operating 16 hours a day to operating 24 hours a day.

■Main benefits of the work
The following benefits were confirmed at trial operation.
1. Improved heat recovery: Roughly double the heat recovery rate from exhaust gas.
2. Reduced power usage: Approx. 40% drop in electricity consumption.
3. Reduced CO2 output: Approx. 60% reduction rate in CO2 output, 20 points above the planned target.

Increasing amounts of energy need to be recovered from waste incineration plants in order for Japan to meet its targets for dealing with global warming. At present, around 70% of waste incineration plants in Japan are believed to lack any power generation equipment. This system allows Hitachi Zosen to contribute to better facility operation and problem-solving by local bodies through.

■Details of the panel boiler-type exhaust heat recovery power generation system for small-scale waste incineration plants
1. Development background
Increasing amounts of energy need to be recovered from waste incineration plants in order for Japan to meet its targets for dealing with global warming. However, there are concerns regarding high installation costs and increasingly complex operation should the approx. 70% of waste incineration plants in Japan that lack any power generation equipment attempt to add power generation equipment. Hitachi Zosen has developed this system in order to provide ease of maintenance and low installation costs by focusing on the boiler, the core piece of equipment in a power generation facility.
2. Features
When installing new power generation equipment in a waste incineration plant, the exhaust gas cooling system needs to be changed from to water-injection to heat recovery. In this system, Hitachi Zosen uses a panel boiler it developed that can be assembled from just four panels, unlike previous complex boiler structures, allowing savings in boiler fabrication and construction costs. In addition, as the setup is simple with little associated equipment, future maintenance and operation do not present worries.
3. Effects
If changing a gas cooling chamber–based cooling system to a panel boiler-based heat recovery system in a plant with an incineration capacity of 90 t/day, the heat recovery rate from exhaust gas will be at least double, allowing a saving of 1,440 MWh in annual facility power consumption. This is equivalent to the annual consumption of 400 normal households, and saves 500 t of CO2 per year. 

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