Two stage hot pipe EGR cooler

Abstract

The invention discloses a two-stage thermotube type EGR cooler. The two-stage thermotube type EGR cooler mainly consists of a shell with an exhaust gas inlet and an exhaust gas outlet respectively arranged on two ends of the cooler and a two-stage thermotube with heating sections arranged inside the shell. The thermotube is communicated with four pipe sections of a heating section, a steam tube, a condensation section and a condensation tube in turn from beginning to end; the heating sections of the two-stage thermotube are arranged along the exhaust gas flow direction in order; and the condensation sections of the two-stage thermotube are overlapped and arranged along the radiation wind blowing direction. In the two-stage thermotube, a first stage thermotube and a second stage thermotuberespectively adopt water and methanol as cooling mediums. The two-stage thermotube type EGR cooler adopts the principle of cooling exhaust gas by the thermotube technology and has good cooling effect. In addition, the reasonable combination of the two-stage thermotube and the cross matching of two radiating mediums further improve the temperature reduction effect of the cooler.

Description

technical field [0001] The invention relates to a gas cooling device, in particular to an exhaust gas recirculation cooler. It can be widely used in power plants using exhaust gas recirculation. Background technique [0002] With the increasingly stringent emission requirements, exhaust gas recirculation technology is increasingly used in power plants. The principle is to cool part of the exhaust gas discharged for the first time and then return it to the engine to effectively reduce the formation of nitrogen oxides in the exhaust gas. The coolers in the traditional exhaust gas recirculation (EGR) process are roughly divided into two types: shell-and-tube type and plate-fin type. They mainly have the following disadvantages: 1. The traditional exhaust gas cooling method uses engine coolant for cooling. Since the coolant in the steam state will cause serious cavitation to the engine cooling circuit, the engine coolant always exists in liquid form under working conditions. ...

AI Technical Summary

Problems solved by technology

They mainly have the following disadvantages: 1. The traditional exhaust gas cooling method uses engine coolant for cooling. Since the coolant in the steam state will cause serious cavitation to the engine cooling circuit, the engine coolant always exists in liquid form under working conditions. That is to say, the cooling of the exhaust gas is carried away by the temperature rise of the engine coolant, which has a poor cooling effect.

2. The conventional EGR cooler adopts shell-and-tube or plate-fin structure, and the compact structure is easier to carbonize, which will greatly reduce the cooling efficiency of the EGR cooler

3. In the traditional shell-and-tube EGR cooler, the weld between the tube bundle and the end plates on both sides is obviously affected by thermal stress and is easy to leak

4. In the traditional shell-and-tube EGR cooler, the flow direction of the exhaust gas is the same as that of the coolant. The purpose is to reduce the degree of vaporization of the coolant, but the cooling effect of the forward flow is not as good as that of the reverse flow.

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