US 2022/0176423 A1Published application

Heat pipe-enhanced heat accumulation type indirect thermal desorption-based soil remediation device and method

AssigneesNanjing Tech University, Cssc Nanjing Luzhou Environment Protection Co., Ltd., Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Rep

InventorsHaitao XU, Yongxian ZHOU, Shengtian ZHANG, Xiang LING, Jisai CHEN, Haiyan QIN, Xiaofeng WANG, Sun HU

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Abstract

A heat pipe-enhanced heat accumulation type indirect thermal desorption-based soil remediation device and method. On the one hand, by using thermal desorption gas generated by soil through heating and volatilizing as a heat transfer medium and by a circular heating manner, hot air efficiently transfers heat to the soil by contact, the treatment capacity of equipment is high. Moreover, high-temperature flue gas is kept from direct contact with the soil, so the high-temperature flue gas is prevented from being mixed with gaseous organic contaminants. Therefore, only a small amount of excess gas needs to be purified, so the equipment scale is small. On the other hand, by equipping a reactor with heat pipes and a ceramic heat accumulator, a second soil heating manner is provided, so that the heat transfer capacity per unit volume of the reactor is increased, and the treatment efficiency is significantly improved under the same scale.

Claims10

Dependent claims

A heat pipe-enhanced heat accumulation type indirect thermal desorption-based soil remediation method, wherein in the method, contaminated soil is conveyed by a feeding device to a feed end of a drum and heated in two manners;

in the first manner, hot air at 550-650° C. from an outlet of a hot air heater enters the drum from a circulating hot air inlet of a discharge end fixed hood and transfers heat with the contaminated soil by direct countercurrent contact such that the contaminated soil is heated;
in the second manner, a heat accumulator at a bottom of the drum releases heat through heat pipes such that the contaminated soil is heated;
as the temperature of the contaminated soil gradually rises to about 300-500° C., water and organic contaminants in the soil are volatilized into a gaseous state and carry dust to become thermal desorption offgas that is separated from the solid soil, and the treated soil is discharged from a treated soil outlet of the discharge end fixed hood;
and
the thermal desorption offgas generated by the contaminated soil being heated inside the drum of a thermal desorption reactor serves as an initial source of circulating hot air, the hot air flows from a circulating hot air outlet of a feed end fixed hood to a dust remover and is subjected to dust removal and driven by a hot air circulating fan, a large part of the hot air is heated to 550-650° C. by the hot air heater through indirect heat exchange, returns to the inside of the drum from the circulating hot air inlet of the discharge end fixed hood, transfers heat with the contaminated soil by direct contact while heating the heat accumulator through the heat pipes such that the temperature drops to 200-300° C., and carries thermal desorption gas generated by the contaminated soil being heated, a part continues to be reused in a hot air circulation loop, and the remaining part is discharged after being purified.

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Dependencies are inferred from the claim text.