CN111250523A - Gas thermal desorption heating well with longitudinal soil heated uniformly - Google Patents

Abstract

The invention discloses a gas-fired thermal desorption additional heat well whose longitudinal soil is uniformly heated, comprising a heat exchange wall casing, a main pipe is arranged in the heat exchange wall casing, an auxiliary pipe is sleeved on the outside of the main pipe, and the outer wall of the auxiliary pipe and the heat exchange wall casing are A spiral deflector is arranged between the inner walls of the auxiliary pipe; holes are arranged on the wall of the auxiliary pipe, the lower opening of the auxiliary pipe is closed, and the main pipe is a structure that is transparent up and down. Through the spiral deflector installed on the auxiliary pipe, the flow velocity of the countercurrent high-temperature flue gas in the shallow soil area is accelerated, the heat transfer coefficient of the heat exchange wall surface is increased, and the downstream high-temperature gas can transfer heat to the auxiliary pipe through the holes In addition, it is conducive to the stability of flue gas temperature, effectively improving the repair efficiency and energy utilization efficiency of gas thermal desorption technology, making the heating of the soil in the longitudinal direction of the target area more uniform, and solving the problem that the shallow soil cannot reach the target temperature. The problem.

Description

An additional heat well for gas heat removal with uniform longitudinal soil heating

technical field

The invention relates to a soil in-situ thermal repair technology, in particular to a gas-fired thermal desorption additional thermal well with uniform longitudinal soil heating.

Background technique

Gas thermal desorption repair technology (GTR) uses clean fuels such as natural gas or petroleum gas as heating energy, and high temperature flue gas generated by combustion is used as heat source. GTR technology is considered to be one of the most cost-effective technologies in soil remediation technology due to its wide range of pollutant treatment, clean energy combustion, short remediation construction period, and large heating depth.

As a key component in GTR technology, the gas heating unit usually consists of a burner and a heating tube. The traditional heating pipe consists of an outer duct and an inner duct. The high-temperature flue gas is first transmitted to the depths of the target treatment site through the inner duct, and then returned to the ground through the outer duct. Since the outer duct is in direct contact with the soil, the high temperature flue gas transfers heat to the surrounding soil through the heat conduction effect. However, when the heating depth is large, the heating temperature at the bottom of the traditional heating tube is high, but the energy output of the shallow soil is very low, and it is difficult to reach the target temperature, so the phenomenon of uneven longitudinal heating of the soil is easy to occur. In the process of gas thermal desorption remediation, if the soil is not uniformly heated longitudinally, the pollutants will be cooled in the extraction pipe, which will block the extraction pipe; the monitoring well will collapse, causing serious consequences such as settlement of the remediation site.

At present, most of the heating pipe equipment of gas thermal desorption repair technology adopts the form of traditional heating pipe, which not only has low repair efficiency and insufficient energy utilization, but also easily produces the phenomenon of uniform longitudinal heating of soil.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a gas-fired heat-extraction additional hot well in which the longitudinal soil is uniformly heated.

The purpose of this invention is to realize through the following technical solutions:

The additional heat well for gas heat removal with uniform longitudinal soil heating of the present invention comprises a heat exchange wall casing, a main pipe is arranged in the heat exchange wall casing, an auxiliary pipe is sleeved on the outside of the main pipe, and the outer wall of the auxiliary pipe is connected to the outer wall of the auxiliary pipe. between the inner walls of the heat exchange wall shell is provided with a spiral guide plate;

Holes are provided on the wall of the auxiliary pipe, the lower opening of the auxiliary pipe is closed, and the main pipe is a structure that is transparent up and down.

It can be seen from the above technical solutions provided by the present invention that the additional heat well for gas heat removal with uniform longitudinal soil heating provided by the embodiment of the present invention, through the spiral deflector installed on the auxiliary pipe, makes the reversing high temperature flue gas at the shallow end. The flow velocity in the soil layer area is accelerated, the heat transfer coefficient of the heat exchange wall surface increases, and the downstream high temperature gas can transfer heat to the outside of the auxiliary pipe through the holes, which is conducive to the stability of the flue gas temperature and effectively improves the gas thermal desorption technology. The restoration efficiency and energy utilization efficiency make the heating of the soil in the longitudinal direction of the target area more uniform, and solve the problem that the shallow soil cannot reach the target temperature.

Description of drawings

Figures 1a, 1b, and 1c are schematic diagrams of the side, cross-section, and cross-sectional structures of the gas-fired thermal desorption additional heat well with uniform longitudinal soil heating according to an embodiment of the present invention.

FIG. 2 is an enlarged schematic diagram of a partial structure of an embodiment of the present invention.

Detailed ways

The embodiments of the present invention will be described in further detail below. Contents that are not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

The preferred specific embodiment of the gas-fired thermal desorption additional heat well with uniform longitudinal soil heating of the present invention is:

It includes a heat exchange wall casing, a main pipe is arranged in the heat exchange wall casing, an auxiliary pipe is sleeved outside the main pipe, and a spiral guide is arranged between the outer wall of the auxiliary pipe and the inner wall of the heat exchange wall casing plate;

Holes are provided on the wall of the auxiliary pipe, the lower opening of the auxiliary pipe is closed, and the main pipe is a structure that is transparent up and down.

The main pipe is nested within the auxiliary pipe in the form of concentric cylinders.

The main pipe is flush with the uppermost part of the auxiliary pipe.

The length of the auxiliary pipe is not greater than the length of the main pipe.

The pitch of the spiral deflector gradually decreases from bottom to top.

The holes are located between the helical baffles.

The arrangement density of the holes gradually increases from bottom to top.

The heat exchange wall shell is a hollow cylinder with a closed bottom, and the heat exchange wall shell is in direct contact with the soil during actual operation.

The inner diameter of the heat exchange wall shell should be just so that there is no gap between the heat exchange wall shell and the spiral guide plate.

The utility model relates to a gas-fired heat-removing additional heat well with uniform longitudinal soil heating, which is a heating pipe with a special structure. On the one hand, the reversing high-temperature gas flows upward through the spiral deflector whose pitch gradually decreases from bottom to top installed on the wall of the auxiliary pipe; the denser spiral at the shallow soil increases the flow rate of the reversing high-temperature gas and heat exchange. The heat transfer coefficient of the wall surface increases. On the other hand, in the inner wall of the auxiliary pipe, a number of holes whose arrangement density gradually increases from bottom to top are opened; the downstream high-temperature gas takes heat to the outside of the auxiliary pipe wall through the opening part and mixes with the counter-current high-temperature gas to adjust the flue gas. It avoids the uneven heating of the soil caused by the high temperature at the bottom of the heating pipe but the low temperature of the shallow layer.

Specific examples:

As shown in Figure 1a, Figure 1b, Figure 1c, Figure 2, the embodiment of the present invention provides a heating pipe with a special structure, including a main pipe 3, an auxiliary pipe 4, a spiral deflector 2, a hole 5, and a heat exchange wall shell 1. The main pipe 3 is nested in the auxiliary pipe 4 in the form of concentric cylinders, the helical baffle 2 is installed outside the auxiliary pipe 4, and the hole 5 is located outside the auxiliary pipe 4; the heat exchange wall shell 1 is a closed hollow cylinder at the bottom, and the heat exchange wall shell 1 is in direct contact with the soil during actual operation.

This embodiment provides a heating pipe with a special structure, and the downward flow path of the flue gas is divided into two parts by the auxiliary pipe 4 and the main pipe 3 . A part flows downward in the main pipe 3 until the bottom of the heating pipe, and then flows upward through the flue gas passage formed by the heat exchange wall shell 1 and the spiral deflector 2 . The other part flows downstream in the auxiliary pipe 4, and is divided once every time it passes through a hole 5, until the hole 5 at the bottom of the auxiliary pipe 4 completely flows into the flue gas passage formed by the auxiliary pipe 4 and the spiral deflector 2, and each time the flow is divided. Both will take part of the heat out of the auxiliary pipe and mix with the reflux high temperature flue gas.

In this field, the high-temperature flue gas flowing downward (inside the main pipe and the auxiliary pipe) is high-temperature flue gas flowing in the upstream direction (the main pipe and the shell of the heat exchange wall, the helical baffles installed on the auxiliary pipe and the heat exchange wall). The high-temperature flue gas of the flue gas passage formed by the casing) is the reverse-flow high-temperature flue gas.

As shown in Figure 1a, Figure 1b, Figure 1c, Figure 2, the helical baffle 2 is directly installed on the auxiliary pipe 4, and the helical pitch decreases from top to bottom, and the inner diameter of the heat exchange wall shell 1 should be Just so that there is no gap between the heat exchange wall shell 1 and the spiral deflector 2, it can be understood that the high temperature flue gas in the reverse flow only passes through the heat exchange wall shell 1 and the spiral deflector 2, and the heat exchange wall shell 1 and the main pipe 3. The two formed flue gas passages circulate. Through the dense spiral guide plates 2 in the shallow area, the flow velocity of the countercurrent high-temperature flue gas is accelerated, and the heat exchange coefficient of the heat exchange wall surface is increased.

The hole 5 is directly excavated on the auxiliary well 4 and is located between the spiral deflectors, that is, the hole 5 should not be directly excavated at the installation position of the spiral deflector. Through the holes 5 , the co-flow high-temperature flue gas in the auxiliary well 4 transfers heat to the flue gas passage formed by the auxiliary well 4 and the helical deflector 2 .

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (9)

1. A gas-fired thermal desorption additional heat well with uniform longitudinal soil heating, characterized in that it comprises a heat exchange wall shell, a main pipe is provided in the heat exchange wall shell, and an auxiliary pipe is sleeved on the outside of the main pipe, and the auxiliary pipe is provided. between the outer wall of the tube and the inner wall of the heat exchange wall shell is provided with a helical baffle; Holes are provided on the wall of the auxiliary pipe, the lower opening of the auxiliary pipe is closed, and the main pipe is a structure that is transparent up and down. 2 . The gas-fired thermal desorption additional heat well with uniform longitudinal soil heating according to claim 1 , wherein the main pipe is nested in the auxiliary pipe in the form of concentric cylinders. 3 . 3 . The additional heat well for gas-fired heat removal with uniform heating of the longitudinal soil according to claim 2 , wherein the main pipe is flush with the uppermost part of the auxiliary pipe. 4 . 4 . The additional heat well for gas-fired heat removal with uniform longitudinal soil heating according to claim 3 , wherein the length of the auxiliary pipe is not greater than the length of the main pipe. 5 . 5 . The gas-fired thermal desorption additional heat well with uniform longitudinal soil heating according to claim 4 , wherein the pitch of the helical deflector gradually decreases from bottom to top. 6 . 6 . The gas-fired thermal desorption additional heat well with uniform longitudinal soil heating according to claim 5 , wherein the holes are located between the spiral guide plates. 7 . 7 . The gas-fired thermal desorption additional heat well with uniform longitudinal soil heating according to claim 6 , wherein the arrangement density of the holes gradually increases from bottom to top. 8 . 8 . The gas-fired heat removal additional heat well with uniform heating of the longitudinal soil according to claim 7 , wherein the heat exchange wall shell is a hollow cylinder with a closed bottom, and the heat exchange wall shell is the same as the actual operation. 9 . direct contact with soil. 9 . The gas-fired heat removal additional heat well with uniform heating of the longitudinal soil according to claim 8 , wherein the inner diameter of the heat exchange wall shell should be just so that the heat exchange wall shell and the helical baffle plate There are no gaps in between.

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