Waste gas economizer upper smoke box capable of preventing rainwater from entering SCR (Selective Catalytic Reduction) reactor

Abstract

An upper smoke box of a waste gas economizer for preventing rainwater from entering an SCR reactor is located at the top of a smoke exhaust system of a generator, the upper smoke box is provided with a cylindrical box body, the top of the box body is provided with a smoke outlet pipe, the smoke outlet pipe is a round pipe, and the bottom of the upper smoke box is open and serves as a smoke inlet; a rain receiving disc is arranged in the box body and below the smoke outlet pipe, the rain receiving disc is in a funnel shape, a water outlet is formed in the center of the rain receiving disc, a distance exists between the water outlet and the smoke inlet, the water outlet is connected with a discharge pipe, the end of the discharge pipe penetrates out of the wall of the box body, and the diameter of a funnel-shaped opening of the rain receiving disc is larger than that of the smoke outlet pipe. And the manhole cover and the end part of the discharge pipe are symmetrically arranged. By optimizing the internal structure of the upper smoke box of the generator waste gas economizer and adding a rainproof structure design, it is guaranteed that rainwater cannot enter the SCR reactor through the smoke exhaust pipe. Meanwhile, smoke exhaust back pressure cannot be generated, and normal operation of a smoke exhaust system of the generator is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of marine vessel design and construction, and specifically relates to a smoke box on the exhaust gas economizer to prevent rainwater from entering the SCR reactor. Background Technology

[0002] To meet Tier III requirements, almost all ship generators now employ low-pressure SCR systems to reduce NOx emissions. Additionally, considering the economic efficiency of ship operations, generator exhaust economizers are often added to the generator exhaust pipes.

[0003] In low-pressure SCR systems, generator exhaust gases must pass through an SCR reactor for catalytic reduction. This reaction requires relatively high exhaust temperatures; therefore, the generator exhaust gases must first pass through the SCR reactor before entering the generator exhaust economizer. The core component of the SCR reactor is the catalyst installed inside. The effectiveness of the catalyst is crucial to whether the generator's NOx emissions meet standards. This catalyst cannot come into contact with water. When the catalyst comes into contact with a large amount of water, its performance is reduced, affecting the catalytic reduction reaction. Simultaneously, the catalyst's structure is altered, resulting in decreased catalyst strength, ultimately leading to reactor failure and hindering repair and maintenance. In severe cases, it can increase the back pressure of the SCR reactor exhaust gases or even cause blockage.

[0004] Because the SCR reactor is located below the generator exhaust economizer, and the outlet of the generator exhaust economizer is generally connected to the flue gas outlet, when the generator in this flue gas system is not running, the flue gas pipe is at room temperature. If it rains, rainwater will enter the flue gas system through the flue gas pipe, pass through the generator exhaust economizer, and then enter the SCR reactor. At this time, the generator should be shut down, so the temperature inside the reactor is also low, making it impossible to evaporate the discharged water. This results in the flushing water submerging the catalyst, and repeated flushing will lead to catalyst failure, failing to achieve the goal of reducing NOx emissions.

[0005] Therefore, it is necessary to design a scheme that can prevent rainwater from entering the SCR reactor when the generator is not running. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides an exhaust gas economizer upper smoke box to prevent rainwater from entering the SCR reactor. The aim is to prevent rainwater from entering the SCR reactor through the exhaust pipe outlet and causing catalyst deactivation. The technical solution adopted is as follows:

[0007] An exhaust gas economizer upper smoke box for preventing rainwater from entering the SCR reactor. The exhaust gas economizer upper smoke box is located at the top of the generator exhaust system. The upper smoke box has a cylindrical box body with a smoke outlet pipe at the top of the box body. The smoke outlet pipe is a circular pipe. The bottom of the upper smoke box is open and serves as a smoke inlet.

[0008] Inside the housing, below the smoke outlet pipe, there is a rain-collecting tray. The rain-collecting tray is funnel-shaped with a drain outlet in the center. There is a gap between the drain outlet and the smoke inlet. The drain outlet is connected to a vent pipe. The end of the vent pipe extends out from the housing wall. The diameter of the funnel-shaped opening of the rain-collecting tray is larger than the diameter of the smoke outlet pipe. A manhole cover is installed on the housing wall. The manhole cover is symmetrically arranged with the end of the vent pipe.

[0009] Furthermore, in the aforementioned method of preventing rainwater from entering the SCR reactor's exhaust gas economizer upper smoke box, the smoke inlet at the bottom of the upper smoke box is connected to the exhaust gas economizer.

[0010] Furthermore, in the above-mentioned method of preventing rainwater from entering the exhaust gas economizer of the SCR reactor, the diameter of the funnel-shaped opening of the rain collection tray is smaller than the diameter of the flue gas inlet.

[0011] Furthermore, in the above-mentioned waste gas economizer smoke box for preventing rainwater from entering the SCR reactor, the funnel-shaped opening of the rain collection tray forms a 15° angle with the horizontal plane.

[0012] Furthermore, the above-mentioned waste gas economizer smoke box for preventing rainwater from entering the SCR reactor is further improved by using a rain collection tray made of 316L stainless steel with a plate thickness of 5mm.

[0013] Furthermore, in the aforementioned method of preventing rainwater from entering the exhaust gas economizer of the SCR reactor, the end of the vent pipe is connected to the bilge water tank.

[0014] By optimizing the internal structure of the upper smoke box of the generator exhaust economizer and adding a rainproof design, rainwater is prevented from entering the SCR reactor through the exhaust pipe. Simultaneously, this prevents the generation of exhaust back pressure, ensuring the normal operation of the generator exhaust system. This invention is applicable to all ships equipped with generator exhaust economizers that meet Tier III standards. For ships already delivered or under construction, the problem can also be solved by modifying the upper smoke box. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the generator exhaust system;

[0016] Figure 2 This is a schematic diagram of the side section of the upper smoke box;

[0017] Among them, 1-SCR reactor, 2-exhaust gas economizer, 3-upper smoke box, 4-smoke inlet, 5-smoke outlet pipe, 6-manhole cover, 7-drain pipe, and 8-rain collection tray. Detailed Implementation

[0018] The invention will be further described with reference to the accompanying drawings.

[0019] An exhaust gas economizer smoke box to prevent rainwater from entering the SCR reactor, such as Figure 1 , 2 As shown, the generator exhaust gas economizer's smoke box includes an inlet. After passing through the generator SCR reactor and the generator exhaust gas economizer, the generator's exhaust gas enters the inlet and then flows into the atmosphere through the exhaust pipe. During rainy weather, rainwater also falls into the inlet through the exhaust pipe, passes through the generator exhaust gas economizer, and then enters the generator SCR reactor. Especially when the generator is not running, the temperature inside the exhaust system is low, and the rainwater will not evaporate, thus causing the catalyst in the reactor to become ineffective.

[0020] Therefore, a vent pipe is added to the side of the upper smoke box, and a rain-collecting tray is installed directly above the smoke inlet. A detailed drawing of the rain-collecting tray is shown in the attached diagram. The inner diameter of the rain-collecting tray needs to be slightly larger than the inner diameter of the exhaust pipe to ensure that rainwater dripping from above is caught by the tray. Since the rain-collecting tray will be in contact with rainwater for a long time, it needs to be corrosion-resistant. The material should be 316L, with a thickness of 5mm. The side of the rain-collecting tray should maintain a 15° slope. Similarly, a sufficiently large gap should be left between the rain-collecting tray and the lower smoke box shell to ensure unobstructed smoke exhaust. This ensures that the collected rainwater flows into the bottom of the rain-collecting tray, while also ensuring that the smoke entering from the smoke inlet enters the exhaust pipe smoothly without being obstructed by the rain-collecting tray, thus preventing an increase in exhaust back pressure. At the same time, the opening at the bottom of the rain-collecting tray needs to be slightly smaller than the inner diameter of the lower vent pipe. The connection method between the vent pipe and the rain-collecting tray is as follows... Figure 2 As shown, this method ensures that rainwater does not remain in the rain collection pan. Instead, it is drained through the drain pipe into the bilge tank for temporary storage. Additionally, the addition of manhole covers allows crew members to periodically open the smoke box to inspect and clean any remaining soot inside.

[0021] This patent provides a solution to the problem of rainwater entering the generator SCR reactor. Simply adding a rain catcher and vent pipe connection to the upper smoke box of the generator exhaust economizer perfectly solves the rainwater problem without increasing the exhaust back pressure of the upper smoke box. This solution is applicable to all ships currently equipped with generator exhaust economizers and required to meet Tier III standards. For ships already delivered or under construction, the problem can also be solved by modifying the upper smoke box.

Claims

1. A flue gas economizer for preventing rainwater from entering the SCR reactor, characterized in that, The exhaust gas economizer upper smoke box is located at the top of the generator exhaust system. The upper smoke box has a cylindrical box body, and the top of the box body has a smoke outlet pipe. The smoke outlet pipe is a circular pipe, and the bottom of the upper smoke box is open, which is the smoke inlet. Inside the housing, below the smoke outlet pipe, there is a rain-collecting tray. The rain-collecting tray is funnel-shaped with a drain outlet in the center. There is a gap between the drain outlet and the smoke inlet. The drain outlet is connected to a vent pipe. The end of the vent pipe extends out from the housing wall. The diameter of the funnel-shaped opening of the rain-collecting tray is larger than the diameter of the smoke outlet pipe. A manhole cover is installed on the housing wall. The manhole cover is symmetrically arranged with the end of the vent pipe.

2. The exhaust gas economizer smoke box for preventing rainwater from entering the SCR reactor according to claim 1, characterized in that, The smoke inlet at the bottom of the upper smoke box is connected to the waste economizer.

3. The exhaust gas economizer smoke box for preventing rainwater from entering the SCR reactor according to claim 1, characterized in that, The diameter of the funnel-shaped opening of the rain-receiving plate is smaller than the diameter of the smoke inlet.

4. The exhaust gas economizer smoke box for preventing rainwater from entering the SCR reactor according to claim 1, characterized in that, The funnel-shaped opening of the rain-receiving tray forms a 15° angle with the horizontal plane.

5. The exhaust gas economizer smoke box for preventing rainwater from entering the SCR reactor according to claim 1, characterized in that, The rain catcher is made of 316L stainless steel with a thickness of 5mm.

6. The exhaust gas economizer smoke box for preventing rainwater from entering the SCR reactor according to claim 1, characterized in that, The end of the vent pipe is connected to the bilge water tank.

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