Kitchen waste hydrothermal treating method and device

Abstract

The invention discloses a kitchen waste hydrothermal treating method and device. The kitchen waste hydrothermal treating method comprises the following steps of rejecting impurities, separating grease, and extracting waste grease at the upper layer in kitchen wastes; performing first-order hydrothermal reaction, namely electrically heating the kitchen wastes after grease separating to realize sequential temperature rising, wherein the hydrothermal reaction temperature is 200-250 DEG C, the reaction time is 5-25 minutes, and a PH value is smaller than 7; performing heat exchange, namely cooling a reactant obtained after the first-order hydrothermal reaction to 130-180 DEG C by virtue of liquid; performing secondary-order hydrothermal reaction, namely carrying out the hydrothermal reaction on the reactant after heat exchange again, wherein the reaction temperature is 130-180 DEG C, and the reaction time is 40-80 minutes; and performing three-phase separation, namely cooling the reactant after the secondary-order hydrothermal reaction until room temperature, and separating solid, liquid and gas. With the adoption of the kitchen waste hydrothermal treating method, the reaction time is shortened, and the energy consumption is low; the process is flexible and accurate to control; the biodegradability of carbonizing liquid can be optimized, and the efficiency of the carbonizing liquid entering the anaerobic treatment process is improved.

Description

technical field [0001] The invention relates to the field of waste recycling, in particular to a method and device for hydrothermal treatment of kitchen waste. Background technique [0002] Common treatment technologies for food waste include anaerobic biogas production, composting, biodiesel extraction, and feed production. [0003] At present, the research on the use of hydrothermal reaction to treat food waste has just started in China. In 1913, German scholar Friedrich Bergius first described the hydrothermal carbonization reaction, and he also won the Nobel Prize in Chemistry in the 1930s. However, the engineering application of hydrothermal carbonization reaction to produce coal-like products with high calorific value is an area that has only begun to receive attention in recent years. Biomass undergoes dehydration and decarboxylation processes under the condition of water as the reaction medium, the pressure is 20-35 Pa, the temperature range is 180°C and 250°C, the...

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Problems solved by technology

However, by increasing the temperature, the reaction time can be reduced, but in the reaction process, in addition to dehydration and decarboxylation, a series of side reactions also occur, especially the formation of water-soluble hydrocarbons, which remain in the hydrothermal reaction liquid, which may cause water The processing cost of the hot reaction liquid increases, and the long-term high-temperature processing has high energy consumption, resulting in high cost

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