The sludge disposal of the sewage treatment plant adopts the pyrolysis gasification process, and the pyrolysis gasifier has a surplus treatment capacity, which can separate the gasifier for biomass gas and carbon cogeneration polygeneration, and the system can be operated after the adaptation of raw materials without new construction. Biomass gasification can realize the polygeneration of gas, activated carbon, steam and electric energy, gas can provide gas for biogas insulation and the heat source for sludge pyrolysis and gasification, activated carbon as an adsorbent for sewage treatment, replacing purchased activated carbon, and can also produce high-quality steam as a by-product.

1. Technical scheme

The biomass is sent into the fixed-bed gasifier, and under the action of the gasifier, the calorific value of combustible gas is 1000~3000kcal/Nm3, and the biochar is obtained in the gasification process, which can be used for sewage purification at the front end of the sewage treatment plant and replaces part of the activated carbon; Part of the steam can be used for sewage treatment plants and external heating, and the rich steam can be used to generate electricity and grid. In this technology, 50% of the heat of 1t biomass is transferred to combustible gas, and about 0.1~0.2t activated carbon can be obtained.

2. Benefit analysis

While the biomass gas carbon cogeneration technology can provide heat for the whole system, the activated carbon produced can be used for sewage treatment at the front end of the sewage plant, which not only saves the energy of the whole system, but also saves the purchase of activated carbon adsorbents at the front end, thereby reducing the cost. After the carbon in the biomass passes through the gasification reactor, part of it is transferred to the flue gas, and after the carbon balance calculation, part of it is transferred to the activated carbon for fixation, and the activated carbon produced can adsorb the carbon-containing substances in the environment. This process is a carbon emission reduction technology with significant environmental benefits. The application of biomass gas and carbon co-generation technology from raw materials to processing processes and products is fully in line with the development direction of green industry, recycling industry and sustainable industry, and can promote the efficient and recycling of biomass and the clean production of activated carbon.