Environmental Protection Treatment

        The biomass gasification heating project in Guangzhou Huanyu can meet the relevant environmental protection requirements by adopting certain environmental protection measures.

1.1 Exhaust gas treatment

        There is no flue gas emission in the biomass gasification process, but after biomass gas is burned in the boiler, a certain amount of boiler tail gas emissions will be produced. The pollutants in the boiler tail gas are mainly nitrogen oxides, sulfur dioxide and soot. The main measures for the treatment of exhaust gas from biomass gas boilers are as follows:

        1) Denitration. The boiler adopts low-nitrogen burner and in-furnace SNCR denitration technology, which can effectively reduce the generation and emission of nitrogen oxides. The nitrogen oxide content in the flue gas can meet the environmental protection requirements of general areas (≤150mg/m³). For areas with strict requirements for nitrogen oxide emissions, SCR denitrification equipment can be installed on the flue to carry out deep denitrification treatment, so as to meet the corresponding environmental protection requirements (≤50mg/m³). However, SCR denitration equipment investment and operating costs are significantly higher than SNCR.

        2) Desulfurization. The sulfur content of biomass raw materials is low, and the SO2 emission after biomass gas combustion is extremely low, which can easily meet environmental protection requirements (≤30mg/m³).

        3) Dust removal. After biomass gas is burned, the content of particulate matter in the exhaust gas of the boiler is not very high. The use of water film for dust removal and the more efficient cyclone washing and dust removal can meet the environmental protection requirements of general areas (≤20mg/m³). Among them, water film dust removal , The content of particulate matter in the exhaust gas of biomass gas boiler can usually be ≤20mg/m³; after cyclone washing and dust removal, the content of particulate matter in the exhaust gas of biomass gas boiler can usually be ≤15mg/m³. For areas with strict exhaust particulate matter emission requirements, the use of bag dust removal equipment to deeply remove the exhaust gas of biomass gas boilers can meet the corresponding environmental protection requirements (≤5mg/m³). The ranking of the investment and operating costs of various types of biomass gas boiler dust removal equipment is: bag dust removal> cyclone washing dust removal> water film dust removal, and the cost of bag dust removal is significantly higher than that of cyclone washing dust removal and water film dust removal.

        The exhaust gas treatment status of Guangzhou Huanyu Energy's existing operating projects is shown in the following table:

1.2 Wastewater treatment

        The biomass gasifier can reduce tar production by controlling the comprehensive moisture content of the biomass raw materials (usually within 25%). The tar water separated from the crude gas can be pyrolyzed and gasified again through zero-emission recycling technology. No waste water is discharged outside the biomass gasification process.

        Biomass gas steam boiler blowdown will produce certain waste water (mainly produced by soft water treatment), which needs to be collected and subjected to unified purification treatment in accordance with relevant boiler regulations.

1.3 Biomass charcoal treatment

        The carbon content of biomass charcoal in wood chip gasifiers can be controlled by manual adjustment. Biomass charcoal with high carbon content can be sold for use as activated carbon, industrial charcoal, and civilian barbecue charcoal, etc.; biomass with low carbon content Charcoal can be used as carbon-based fertilizer and soil remediation agent.