Zhejiang Lishui Biomass Boiler Flue Gas Treatment Project Successfully Passed Final Acceptance

Recently, the flue gas treatment systems for two biomass steam boilers undertaken by our company for the centralized heating project in the Lishui Industrial Park, Zhejiang Province, have successfully completed commissioning. All emission indicators have remained stable and compliant, and the project has successfully passed the owner's final acceptance inspection.

The project is equipped with one 36 t/h biomass steam boiler and one 50 t/h biomass steam boiler. The original flue gas conditions were complex: the flue gas temperature at the furnace outlet reached 335°C, the total flue gas volume under standard conditions reached 120,000 Nm³/h, and the initial particulate matter concentration was as high as 2,000 mg/Nm³. The project uses bulk biomass fuel, resulting in significant fluctuations in dust and tar content in the flue gas, which placed high requirements on the stability of the treatment system.

To address the flue gas temperature characteristics and operating challenges of biomass boilers, our company customized a proven ultra-clean treatment process consisting of in-furnace SNCR denitrification + multi-cyclone dust collector + medium-temperature SCR denitrification + low-pressure long-bag pulse bag filter + shared spray desulfurization tower.

• SNCR denitrification was first applied in the furnace temperature zone of 700–900°C, reducing the initial NOₓ concentration by more than 40% in advance and lowering the operating load of the downstream SCR module.

• The front-end multi-cyclone dust collector intercepts large-particle fly ash in advance, significantly reducing the wear risk of the downstream SCR catalyst caused by high-dust flue gas while also reducing the filtration load on the downstream bag filter.

• The supporting medium-temperature SCR module operates stably within the temperature range of 280–350°C, further removing nitrogen oxides.

• The shared spray desulfurization tower at the final stage treats the flue gas from both boilers, achieving efficient desulfurization. The measured emission values at the stack outlet remained stable at NOₓ ≤ 50 mg/Nm³, SO₂ ≤ 35 mg/Nm³, and particulate matter ≤ 10 mg/Nm³, fully meeting local environmental emission requirements.

Since the start of construction, our project team has closely coordinated with the heating schedule of the industrial park, reasonably arranging installation and commissioning procedures. As a result, the entire system was successfully put into integrated operation three days ahead of the scheduled completion date and has now been operating stably for several months.

The successful delivery of this project represents another benchmark application of our company in the field of flue gas treatment for bulk biomass boilers and provides a mature and replicable reference solution for ultra-low emission upgrades of biomass-based centralized heating projects in industrial parks across China.