Renovation of Old Factory Achieved Remarkable Results and Received Recognition from the Ministry of the Environment.

Since July 2017, the subsidiary ECOVE Environment Services Corp. (under ECOVE) has been responsible for the operations and maintenance of the Gangshan plant. The plant has faced challenges due to limited incineration capacity and excessive inflow of raw waste, resulting in frequent overflow of the waste storage pit. After taking over the contract, ECOVE Environment Services Corp. conducted a comprehensive review of all systems and identified two key factors that significantly impact incineration processing efficiency: poor incineration efficiency of the furnace bed and leaks in the exhaust gas system. Regarding the issues with the furnace bed, the team prioritized the organization of the air box, removing internal dust accumulation to ensure smooth primary air delivery and provide sufficient combustion air. For the exhaust gas system, the team repaired the flue gas leakage points and replaced the filter bags to reduce differential pressure and enhance exhaust gas filtration efficiency.
In November 2021, ECOVE Environment Services Corp. officially undertook the Gangshan ROT project and initiated a comprehensive equipment and system improvement plan, primarily covering the following four key areas:

I. Equipment replacement and system upgrade

Replacement of outdated equipment, including bag-type dust collectors, Distributed Control Systems (DCS), steam turbine Programmable Logic Controllers (PLC), garbage hoist rail tracks, and hoist PLCs. The renewal of the DCS, gas turbines, and crane PLC not only ensure a reliable supply of spare parts in the future but also enhance system stability. Additionally, the renewal of the crane tracks reduces abnormal conditions and improves equipment reliability.

II. Enhancing operational efficiency

To enhance incineration efficiency, modifications were made including the lowering of the drying section grate, the replacement of high-alloy coated furnace tubes, and the replacement of the ACC fan blades with Fiber Reinforced Plastic (FRP) blades. The lowering of the furnace bed 
effectively reduces the slagging condition of the furnace wall. The high-alloy coated furnace tubes enhance waste heat absorption, thereby increasing steam production. Additionally, the lightweight FRP fan blades reduce the load and decrease power consumption. Additionally, the installation of variable frequency control systems for the primary and secondary air fans has replaced the fixed operation mode, resulting in a reduction of current from an average of 92A to 27A, achieving an energy savings of 70%

III. Reduction of air pollutant emissions

To reduce pollutant emissions, catalytic filter bags and a Selective Catalytic Reduction (SCR) system have been introduced, and sodium bicarbonate is now used as the acid removal agent. Sodium bicarbonate exhibits a higher reaction temperature for deacidification. When used in conjunction with catalytic filter bags, it effectively reduces the concentration of nitrogen oxides (NOx) emissions, further decreasing pollutant discharge and complying with environmental protection standards, thereby being environmentally friendly

IV. Recycling and reuse of energy resources

In line with the principles of a circular economy, we are promoting the recycling of bottom slag metals, the application of waste heat recovery boilers, and the use of regenerative variable frequency drives for cranes. The bottom ash is processed through magnetic separation and eddy current technology to recover metal resources.  The recovery of residual heat from flue gas generates steam, which serves as a thermal source for the process, replacing the steam extracted from the turbine. The crane grab energy recovery 
technology converts previously consumed electrical energy into reusable energy. These measures reflect the principles of resource recycling and sustainable management.

V. Results and outlook

Following a series of equipment improvements and system optimizations, the operational performance in 2024 has significantly improved compared to 2023. The unexpected downtime has been reduced by 422 hours, the average incineration volume has increased by 23%, and the amount of bottom ash metal recovered has reached 1,715 tons. In the future,ECOVE Environment Services Corp. will continue to deepen technological upgrades and environmental innovations to enhance operational efficiency, while implementing resource recycling and sustainable development, thereby contributing greater value to environmental protection.

Calcium oxide is replaced by sodium bicarbonate as the deacidification agent(left)、 Replacement of ACC fans with Fiberglass Reinforced Plastic (FRP) blades and other modifications(right)