Ammonia-diesel dual-fuel engine post-processing structure and ammonia-diesel dual-fuel engine system

Abstract

The utility model relates to a post-processing structure of an ammonia-diesel dual-fuel engine, which comprises a selective catalytic reducer and an ammonia escape catalyst formed at one end of the selective catalytic reducer and communicated with the selective catalytic reducer, and the other end of the selective catalytic reducer is provided with an air outlet. And the free end of the ammonia escape catalyst is provided with an air inlet. By exchanging the positions of the selective catalytic reduction device and the ammonia escape catalytic device, the other end of the selective catalytic reduction device is provided with the gas outlet, the free end of the ammonia escape catalytic device is provided with the gas inlet, and therefore an original urea injection structure can be omitted (urea injection is not needed), and the content of ammonia and nitrogen oxide in tail gas can be increased.

Description

Technical Field

[0001] This utility model belongs to the field of exhaust gas treatment technology, and relates to an engine aftertreatment structure, specifically to an ammonia-diesel dual-fuel engine aftertreatment structure and an ammonia-diesel dual-fuel engine system. Background Technology

[0002] Currently, the most researched high-power gas fuel engines include various types, such as natural gas engines, ammonia engines, and hydrogen engines, which are mainly used in road transportation, non-road engineering machinery, and marine power.

[0003] In an ammonia-diesel engine, diesel fuel and ammonia gas enter the cylinder together. The diesel fuel is ignited by compression, and the resulting flame ignites the ammonia gas, causing them to burn together and release heat to produce power. However, the ammonia gas cannot be completely burned in the cylinder, and some ammonia gas, along with other exhaust pollutants, is discharged from the exhaust pipe.

[0004] Current technologies for treating ammonia emissions utilize ammonia slip catalysts (ASCs). The dominant chemical reaction in an ASC is the reaction of ammonia (NH3) with oxygen (O2), primarily producing nitrogen (N2) and water (H2O). However, ammonia may not have sufficient oxygen to participate, leading to partial or incomplete oxidation and the production of nitrogen oxides (NOx). x Nitrous oxide (N₂O) or nitrous oxide (NO₃) is used in exhaust gases. Currently, selective catalytic reduction (SCR) is used to treat nitrogen oxides (NO₃) in exhaust gases. x The nitrogen oxides (NO) are reduced to harmless nitrogen (N2) and water (H2O). This can be achieved using reducing agents (such as ammonia (NH3) or urea (CO(NH2)2)). Typical chemical reactions are as follows: 4NO + 4NH3 + O2 → 4N2 + 6H2O, 2NO2 + 4NH3 + O2 → 3N2 + 6H2O. Because nitrogen oxides and unburned ammonia constitute a relatively high concentration in the exhaust of ammonia-diesel engines, there is currently no effective aftertreatment device to handle the complex exhaust composition of ammonia-diesel engines.

[0005] Chinese invention patent application number 202211509562.X discloses an exhaust gas treatment device and method for an ammonia-diesel engine. The exhaust gas treatment device includes a pre-SCR-ASC assembly, a DOC (Diesel Oxide Filter), a DPF (Diesel Per Filter), and a post-SCR-ASC assembly arranged sequentially. In both the pre-SCR-ASC and post-SCR-ASC assemblies, the SCR (Self-Catalyst) is located at the front end of the ASC (Automatic Filter). The pre-SCR assembly has an electric heating device at its front end, and the post-SCR-ASC assembly has an ammonia nozzle at its front end. The ammonia nozzle is connected to a liquid ammonia tank, which serves as the ammonia source for the ammonia-diesel engine. In this application, the SCR is located at the front end of both the pre-SCR-ASC and post-SCR-ASC assemblies, ensuring that the exhaust gas first enters the SCR and then the ASC for treatment. Chinese invention patent application number 202411016800.2 discloses an exhaust gas treatment device and method for an ammonia-diesel engine, relating to the field of ammonia-diesel engine exhaust gas treatment technology. A selective catalytic reduction (SCR), an ammonia oxidation catalyst, and a particulate filter are connected sequentially from front to back. An ammonia nozzle is provided at the front end of the SCR, connected to the ammonia source of the ammonia-diesel engine. A first temperature sensor and a first nitrogen-oxygen sensor are also provided at the front end of the SCR, as is a first ammonia sensor. The first temperature sensor, the first nitrogen-oxygen sensor, and the first ammonia sensor are electrically connected to the aftertreatment unit of the ammonia-diesel engine. In this application, the SCR and the ammonia oxidation catalyst are also arranged sequentially from front to back, ensuring that the exhaust gas passes through the SCR and then the ammonia oxidation catalyst.

[0006] However, the ammonia content in the exhaust gas after treatment by the exhaust gas treatment device with the above structure can be as high as about 2000 ppm and the nitrogen oxide content can be as high as about 600 ppm, which still has a relatively high degree of air pollution and there is a need for further reduction. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by providing an aftertreatment structure for an ammonia-diesel dual-fuel engine.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is: an aftertreatment structure for an ammonia-diesel dual-fuel engine, which includes a selective catalytic reduction device and an ammonia escape catalyst formed on and connected to one end of the selective catalytic reduction device, the other end of the selective catalytic reduction device having an outlet, and the free end of the ammonia escape catalyst having an inlet.

[0009] Ideally, the cross-sectional diameter of the ammonia escape catalyst and the cross-sectional diameter of the selective catalytic reducer are independently 11 to 15 inches.

[0010] Furthermore, the width of the ammonia escape catalyst and the cross-sectional diameter of the selective catalytic reducer are independently 4 to 8 inches.

[0011] Ideally, the inner wall of the support of the ammonia escape catalyst has a noble metal catalyst coating, wherein the coating density of the noble metal is 1.0~1.5 g / ft. 3 .

[0012] Ideally, the carrier material of the selective catalytic reducer is an iron-based material.

[0013] Another object of the present invention is to provide an ammonia-diesel dual-fuel engine system comprising the ammonia-diesel dual-fuel engine aftertreatment structure described above.

[0014] Optimally, it includes:

[0015] Ammonia-diesel dual-fuel engine;

[0016] An intake pipe, one end of which is connected to the ammonia-diesel dual-fuel engine;

[0017] An exhaust pipe, one end of which is connected to the ammonia-diesel dual-fuel engine;

[0018] A turbocharger, which is installed inside the intake pipe and the outlet pipe;

[0019] The aftertreatment structure of the ammonia-diesel dual-fuel engine is installed on the exhaust pipe and located downstream of the turbocharger.

[0020] Furthermore, it also includes an intercooler mounted on the intake manifold and located downstream of the turbocharger.

[0021] Furthermore, it also includes a throttle valve mounted on the intake manifold and located between the intercooler and the ammonia-diesel dual-fuel engine.

[0022] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art: The aftertreatment structure of the ammonia-diesel dual-fuel engine of this utility model, by interchange of the positions of the selective catalytic reduction unit and the ammonia escape catalyst, makes the other end of the selective catalytic reduction unit have an outlet and the free end of the ammonia escape catalyst have an inlet. This eliminates the original urea injection structure (i.e., no need to inject urea), and can increase the content of ammonia and nitrogen oxides in the exhaust gas. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the aftertreatment structure of the ammonia-diesel dual-fuel engine of this utility model. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0025] like Figure 1 The aftertreatment structure 1 of the ammonia-diesel dual-fuel engine shown includes a selective catalytic reduction (SCR) 11 and an ammonia escape catalyst 12 formed on and connected to one end of the SCR 11 (the formation method can be conventional, such as welding). The SCR 11 and the ammonia escape catalyst 12 are arranged in parallel and symmetrical about their joint. Unlike conventional structures, the other end of the SCR 11 (the end opposite to the ammonia escape catalyst 12) has an outlet 111, and the free end of the ammonia escape catalyst 12 (the end opposite to the SCR 11) has an inlet 121. This eliminates the need for the original urea injection structure (i.e., urea injection is unnecessary), thereby increasing the content of ammonia and nitrogen oxides in the exhaust gas.

[0026] In this embodiment, the cross-sectional diameter c of the ammonia escape catalyst 12 and the cross-sectional diameter d of the selective catalytic reduction device 11 are independently 11-15 inches, preferably 13 inches; the width b of the ammonia escape catalyst 12 and the cross-sectional diameter a of the selective catalytic reduction device 11 are independently 4-8 inches, preferably 6 inches, to adapt to the high concentration of ammonia and nitrogen oxides in the exhaust gas of ammonia-diesel engines. The inner wall of the carrier of the ammonia escape catalyst 12 has a noble metal catalyst coating (preferably noble metal Pt), and the coating density of the noble metal in the noble metal catalyst coating is 1.0-1.5 g / ft. 3 To adapt to the high proportion of ammonia and nitrogen oxides in the exhaust gas of ammonia-diesel engines, the selective catalytic reducer 11 is made of iron-based material to adapt to the emission characteristics of nitrous oxide in the exhaust gas of ammonia-diesel engines.

[0027] The application of the above-mentioned aftertreatment structure 1 for ammonia-diesel dual-fuel engines is also as follows: Figure 1 As shown, this is used in an ammonia-diesel dual-fuel engine system. The ammonia-diesel dual-fuel engine system includes an ammonia-diesel dual-fuel engine aftertreatment structure 1, an intake pipe 2, a turbocharger 3, an ammonia-diesel dual-fuel engine 6, and an exhaust pipe 7. One end of the intake pipe 2 is connected to the ammonia-diesel dual-fuel engine 6 to introduce fresh air into it. One end of the exhaust pipe 7 is connected to the ammonia-diesel dual-fuel engine 6 to exhaust the exhaust gas produced by it. The turbocharger 3 is installed inside the intake pipe 2 and the exhaust pipe 7 to pressurize the intake air (the turbocharger 3 can be a conventional type, including a compressor installed in the intake pipe 2 and a turbine installed in the exhaust pipe 7 and connected to the compressor via a shaft). In this case, the ammonia-diesel dual-fuel engine aftertreatment structure 1 is installed on the exhaust pipe 7 and downstream of the turbocharger 3; its connection method is described in [reference needed]. Figure 1 .

[0028] In this embodiment, the ammonia-diesel dual-fuel engine system also includes an intercooler 4 installed on the intake pipe 2 and located downstream of the turbocharger 3, and a throttle valve 5 installed on the intake pipe 2 and located between the intercooler 4 and the ammonia-diesel dual-fuel engine 6. This can reduce the temperature of the high-temperature air after turbocharging, the thermal load of the ammonia-diesel dual-fuel engine 6, and can adjust the intake air volume to increase engine power.

[0029] The effectiveness of the above-mentioned ammonia-diesel dual-fuel engine aftertreatment structure 1 was tested on an engine test bench. Engine information and test conditions are shown in Table 1 below. (In addition, the specific parameters of the ammonia-diesel dual-fuel engine aftertreatment structure 1 are as follows: the cross-sectional diameter c of the ammonia escape catalyst 12 and the cross-sectional diameter d of the selective catalytic reduction unit 11 are independently 13 inches; the width b of the ammonia escape catalyst 12 and the cross-sectional diameter a of the selective catalytic reduction unit 11 are independently 6 inches; the coating density of Pt in the noble metal catalyst coating on the inner wall of the carrier of the ammonia escape catalyst 12 is 1.2 g / ft.) 3 The carrier material of the selective catalytic reduction unit 11 is an iron-based material (such as commercially available 0cr25Al5, and other parameters are all conventional). An existing structure was also used for comparison. This existing structure is basically the same as the aforementioned ammonia-diesel dual-fuel engine aftertreatment structure 1 (referred to as Example 1), except that air enters through outlet 111 and exits through inlet 121. That is, the ammonia-diesel dual-fuel engine aftertreatment structure 1 is rotated 180° before being connected accordingly (referred to as Comparative Example 1).

[0030] Table 1 Engine Information and Test Condition Information

[0031]

[0032] Note: 350kw@1500rpm is the fixed operating condition in actual application of ammonia diesel engine.

[0033] The obtained experimental data are shown in Table 2: the treatment efficiency for ammonia (NH3) was 99.91%, for hydrocarbons (HC) it was 90.67%, and for nitrogen oxides (NO) it was 90.67%. x The treatment efficiency was 88.36%, with nitric oxide (NO) treatment efficiency at 86.52%, nitrogen dioxide (NO2) treatment efficiency at 69.61%, and nitrous oxide (N2O) treatment efficiency at 51.68%, resulting in a significant reduction in exhaust pollutants.

[0034] Table 2 Comparison of Experimental Data

[0035]

[0036] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. An ammonia-diesel dual fuel engine aftertreatment arrangement comprising a selective catalytic reducer (11) and an ammonia slip catalyst (12) formed on one end of the selective catalytic reducer (11) and in communication therewith, characterized in that: The other end of the selective catalytic reducer (11) has a gas outlet (111), and the free end of the ammonia escape catalyst (12) has a gas inlet (121); The cross-sectional diameter (c) of the ammonia escape catalyst (12) and the cross-sectional diameter (d) of the selective catalytic reducer (11) are independently 11-15 inches. The width (b) of the ammonia escape catalyst (12) and the cross-sectional diameter (a) of the selective catalytic reducer (11) are independently 4-8 inches.

2. The ammonia-diesel dual fuel engine aftertreatment structure of claim 1, wherein: The inner wall of the carrier of the ammonia slip catalyst (12) has a noble metal catalyst coating, the coating density of noble metal in the noble metal catalyst coating is 1.0~1.5g / ft 3 .

3. The ammonia-diesel dual fuel engine aftertreatment structure of claim 1, wherein: The carrier material of the selective catalytic reducer (11) is iron-based material.

4. An ammonia-diesel dual fuel engine system, characterized by, It contains the ammonia-diesel dual-fuel engine aftertreatment structure (1) as claimed in any one of claims 1 to 3.

5. The ammonia-diesel dual fuel engine system of claim 4, wherein, It comprises: an ammonia-diesel dual-fuel engine (6); an air inlet pipe (2) having one end connected to the ammonia-diesel dual-fuel engine (6); an air outlet pipe (7) having one end connected to the ammonia-diesel dual-fuel engine (6); a supercharger (3) installed in the air inlet pipe (2) and the air outlet pipe (7); the ammonia-diesel dual-fuel engine aftertreatment structure (1) is installed on the air outlet pipe (7) and downstream of the supercharger (3).

6. The ammonia-diesel dual fuel engine system of claim 5, wherein: It further comprises an intercooler (4) installed on the air inlet pipe (2) and downstream of the supercharger (3).

7. The ammonia-diesel dual fuel engine system of claim 6, wherein: It further comprises a throttle valve (5) installed on the air inlet pipe (2) and between the intercooler (4) and the ammonia-diesel dual-fuel engine (6).

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