External-heating double-position spiral drying roasting kiln for ex-situ remediation of soil

Abstract

The invention discloses an external-heating double-position spiral drying roasting kiln for ex-situ remediation of soil. The furnace comprises upper and lower furnace bodies, wherein two furnace tubesare arranged in each of the upper and lower furnace bodies; a feeding bin is connected with a feeding hole of the upper furnace tube through a rotary vane type feeder; a rotary vane feeder is connected with a driving motor with a frequency converter; spiral conveying augers are arranged in the upper furnace tube and the lower furnace tube and are connected with a transmission speed reducer with afrequency converter; the working frequency of the rotary vane feeder is equal to the spiral conveying frequency of the spiral conveying auger, so that the consistency of front and back feeding speedsis ensured; the right sides of the upper furnace tube and the lower furnace tube are vertically communicated; a discharge conveyor is arranged at a discharge hole in the bottom of the lower furnace tube; a water spraying humidifier is arranged at the top of the upper furnace tube; and a combustor is arranged at bottom of furnace body. The spiral drying roasting kiln is small in size, low in siterequirement, high in thermal desorption efficiency, low in equipment failure rate and low in energy consumption; in the spiral drying roasting kiln, the furnace tube adopts a segmented flange connection mode, so that the service life of the furnace tube can be prolonged, the furnace tube replacement cost is reduced, gaps between the furnace tube and a hearth can be eliminated, and heat dissipationis reduced.

Description

technical field [0001] The invention belongs to the technical field of soil restoration equipment, and relates to a drying and roasting kiln, in particular to an external heating double-position spiral drying and roasting kiln for heterotopic soil restoration. Background technique [0002] Thermal desorption technology is an important means of contaminated soil remediation technology. Thermal desorption technology is a process in which the target organic pollutants are volatilized or separated from the soil by heating the contaminated soil above the boiling point of the target pollutants. During the desorption process, the target pollutants undergo evaporation, distillation, boiling, oxidation and pyrolysis. By controlling the system temperature and material residence time, different pollutants can be selectively removed. The pollutants in the polluted soil are under negative pressure conditions It is separated from the soil and finally enters the gas treatment system for co...

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Problems solved by technology

However, during the operation of the rotary furnace or other thermal desorption equipment, the failure rate of the equipment is high, the energy consumption is large, the use is inconvenient, the thermal desorption efficiency is low, the running time is long, the operation and maintenance are relatively complicated, and the equipment The investment cost is also relatively large, and there may be secondary pollution during the operation process. Moreover, the existing equipment is large in size, has high requirements for the site, and requires pre-screening and crushing of the soil, which increases the cost of thermal desorption.

[0005] In addition, the current general-purpose thermal desorption furnace tube has the following defects: the existing general-purpose thermal desorption furnace tube has only one side ( The right side) is fixed by the bearing, and the auger and the material it conveys have gravity, which causes the helical blade on the other side (left side) of the auger axis to directly contact the inner wall of the furnace tube, causing the auger to contact the furnace tube during rotation. The side of the inner wall of the tube in contact with the continuous friction makes the tube wall of the furnace tube thinner; moreover, the temperature inside the furnace usually reaches above 550°C. That is to say, the furnace tube needs to be replaced in about one year; and the replacement of the furnace tube is relatively difficult, and the replacement of the furnace tube takes a long time, the cost is high, and the shutdown of the construction site will also cause great losses

At the same time, the existing general-purpose furnace tube design will also lead to a large gap between the furnace tube and the furnace (furnace body), resulting in heat dissipation and high energy consumption, which is not conducive to energy saving and consumption reduction.

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