A self-sufficient heat self-sufficient municipal sludge continuous hydrothermal carbonization system and method

Abstract

The invention discloses a thermal self-sufficient municipal sludge continuous hydrothermal carbonization system and method. The system includes a carbonization device and a wet heat oxidation device. The carbonization device includes a sludge pump, a preheater, a heater, a first start-up heater, Carbonization reactor, cooler, storage tank and filter press; the wet heat oxidation device includes filtrate pump, oxygen compressor, heat exchanger, second start-up heater, catalytic reactor and gas-liquid separator, and the carbonization device provides COD is used as an energy source, and the wet heat oxidation device provides carbonization heat and temperature for the carbonization device, so that the entire sludge carbonization system realizes heat self-sufficiency without external heat supply, and uses COD in the sludge charcoal filtrate as a heat source, which saves significant energy. At the same time, the sludge charcoal The COD and TN in the filtrate are oxidized to carbon dioxide and nitrogen, so that the waste water can be discharged up to the standard, and it has the advantages of energy saving, low production cost and zero discharge of pollutants. The invention simultaneously discloses the municipal sludge continuous hydrothermal carbonization method.

Description

technical field [0001] The invention relates to the technical field of municipal sludge resource utilization, in particular to a self-sufficient heat self-sufficient municipal sludge continuous hydrothermal carbonization system and method. Background technique [0002] In recent years, the total amount and treatment rate of sewage treatment in my country have been rapidly increased. Sludge is one of the important links in the sewage treatment process. The sewage treatment process transfers most of the pollutants to the sludge. If not handled properly, it is easy to cause secondary pollution to the environment. At the same time, sludge also contains a lot of rich nutrients, which can be used as fertilizer and energy materials after proper treatment. Therefore, how to properly treat sludge, make it stable, harmless, reduce, and recycle, has become an urgent problem to be solved in sludge treatment. [0003] The treatment methods currently used include composting, anaerobic d...

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: 1. The sludge drying consumes a lot of energy and the cost is too high; 2. The sulfur dioxide and nitrogen oxides in the carbonized combustion tail gas are too high, so the treatment is difficult; 3. It is necessary to apply to the Environmental Protection Bureau for a large amount of total emission indicators

The disadvantages of this technology are: 1. It needs to consume a lot of energy to dry the sludge; 2. The combustible gas produced by high-temperature carbonization needs to be burned to provide carbonization heat. The combustible gas contains a large amount of sulfur and nitrogen compounds, which are produced during combustion. High-concentration sulfur dioxide and nitrogen oxide tail gas requires a complex tail gas treatment system. At the same time, it needs to apply for a large number of total emission indicators, which is not easy to be accepted by the environmental protection department.

At present, there are two low-temperature hydrothermal carbonization processes in the industry: one is to directly heat the sludge with steam, the temperature rises to 190-200°C, and the pressure is 2-2.5MPa. The disadvantages of this process are: 1. Because the steam directly enters the sludge In the mud, the sludge is diluted, which reduces the volume production capacity; 2. Because the sludge is diluted, a large amount of high-concentration waste liquid is produced, which reduces the carbon yield; 3. Because the carbonization temperature is low, the product sludge has a charcoal smell Strong smell, unfavorable to the factory environment and subsequent product utilization

Disadvantages of this process: 1. Although the higher temperature method saves energy, the energy consumption is still high; 2. The higher hydrothermal carbonization temperature leads to the high content of organic matter cracking products aldehydes and furans in the carbonization waste liquid. Sequence waste liquid is difficult to biochemically treat

The disadvantages of this technology are: 1. Higher energy consumption (much lower than the high-temperature carbonization method); 2. The high-concentration and high-pollution carbonization waste liquid needs to be treated; 3. The high-concentration carbonization waste liquid contains a large amount of toxic heat that cannot be biochemically solution product

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