CN108590842A - A kind of ethyl alcohol reforms the natural gas engine of auxiliary combustion online - Google Patents

Abstract

The purpose of the present invention is to provide the natural gas engines that a kind of ethyl alcohol reforms auxiliary combustion online, including working cylinder, reformed gas cylinder, natural gas storage tanks, ethyl alcohol storage tank, mixer, the inlet communication inlet manifold of working cylinder, the outlet exhaust main of working cylinder, inlet manifold is connected to mixer, exhaust main is respectively communicated with heat exchanger and the turbine inlet of turbocharger, the blower outlet of turbocharger is connected to mixer, the outlet heat exchanger of natural gas storage tanks, two outlets of heat exchanger are respectively communicated with mixer and air, the inlet communication ethyl alcohol holding vessel of reformed gas cylinder, the outlet of reformed gas cylinder has the buffering gas tank of collection and the hydrogen-rich reformed airway dysfunction of storage, it buffers gas tank and is connected to mixer.The present invention can avoid individually producing, storing, transporting the trouble of hydrogen, and hydrogen loading, which is burnt, can effectively play the advantage of lean burn, inhibits pinking and prevents phenomenon of catching fire, ensures the burning of ignition type natural gas engine high-efficiency cleaning.

Description

A natural gas engine with auxiliary combustion for ethanol on-line reforming

technical field

The present invention relates to an internal combustion engine, in particular a natural gas engine.

Background technique

Natural gas is widely used in the engine industry because of its high calorific value, clean emissions and abundant reserves. For spark-ignited natural gas engines, if run in a mode close to the equivalence ratio, the remote mixture tends to spontaneously ignite before the flame reaches, causing knocking. Lean combustion (Φa>1) is generally used to suppress this phenomenon. But when the mixture is leaner, the combustion speed is slow, resulting in low thermal efficiency of natural gas engines and a sharp increase in hydrocarbon (HC) emissions. In extreme cases, flame quenching or partial duty cycle misfires may even occur.

In order to solve the above problems, some researchers proposed to add an appropriate amount of hydrogen to natural gas, and use the characteristics of hydrogen’s fast combustion speed to accelerate the combustion process of the mixture in lean burn mode, so as to achieve efficient and clean combustion while suppressing knocking. However, the content of pure hydrogen in nature is extremely low, and it needs to be produced by consuming other energy sources through certain methods.

As a renewable energy source, bioethanol can be obtained through grain fermentation and biomass degradation. And the carbohydrate itself is formed by fixing free carbon in the atmosphere, and burning or reforming will not bring additional burden to the atmospheric environment. After a certain catalytic reaction, ethanol can be reformed to form a mixed gas rich in hydrogen and carbon monoxide, which is used to assist the combustion of natural gas engines. However, the system structure and control process of the single ethanol reforming hydrogen production unit are complicated, and the storage and transportation of hydrogen are difficult, which increases the overall cost.

Contents of the invention

The purpose of the present invention is to provide a kind of ethanol online reforming assisted combustion natural gas engine which can accelerate the combustion process of lean mixed natural gas, avoid knocking and misfire, and realize efficient and clean combustion.

The purpose of the present invention is achieved like this:

A natural gas engine for ethanol on-line reforming auxiliary combustion, characterized in that it includes a working cylinder, a reforming cylinder, a natural gas storage tank, an ethanol storage tank, a turbocharger, and a mixer, the inlet of the working cylinder is connected to the intake manifold, and the working The outlet of the cylinder is connected to the exhaust manifold, the intake manifold is connected to the mixer, the exhaust manifold is respectively connected to the heat exchanger and the turbine inlet of the turbocharger, the compressor outlet of the turbocharger is connected to the mixer, and the outlet of the natural gas storage tank is connected to Heat exchanger, the two outlets of the heat exchanger are respectively connected to the mixer and the atmosphere, the inlet of the reforming cylinder is connected to the ethanol storage tank, and the outlet of the reforming cylinder is connected to the buffer gas tank with the function of collecting and storing hydrogen-rich reformed gas. The gas tank communicates with the mixer.

The present invention may also include:

1. An ethanol injection valve is installed on the top of the cylinder head of the reforming cylinder, and a CuO/ZnO/Al ₂ O ₃ catalytic module with a sponge-loaded structure is installed on the piston of the reforming cylinder.

2. A throttle valve is set at the compressor inlet of the turbocharger, a natural gas flow valve is set between the purifier and the mixer, a reformed gas flow valve is set between the buffer gas tank and the mixer, and the inlet of the ethanol storage tank and the reforming cylinder Set the ethanol flow valve in between.

3. The combined effect of the throttle valve and the natural gas flow valve makes the air-fuel equivalence ratio in the working cylinder greater than 1; under cold start or low load, the hydrogen-rich mixture stored in the buffer gas tank passes through the reformed gas flow valve into the mixture device.

The advantages of the present invention are:

1. Using natural gas as the main fuel, ethanol reforming produces hydrogen-rich mixed gas to accelerate combustion, which can effectively suppress the knocking and misfire phenomena of ignition-type natural gas engines, and achieve efficient and clean combustion;

2. Ethanol reacts in the reforming cylinder, and the high-temperature environment makes the conversion efficiency higher, which can effectively increase the hydrogen content in the mixed gas;

3. Use CuO/ZnO/Al ₂ O ₃ catalyst instead of noble metal catalyst to reduce cost;

4. A buffer gas tank is installed to store reformed gas, so that natural gas can also be burned efficiently under cold start or low load conditions, ensuring the normal operation of the engine.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Detailed ways

The present invention is described in more detail below in conjunction with accompanying drawing example:

In conjunction with Fig. 1, a kind of ethanol on-line reforming auxiliary combustion natural gas engine of the present invention comprises a turbocharger 5, an intercooler 6, a mixer 7, a heat exchanger 2, a buffer gas tank 13, a working cylinder 10, a reforming Cylinder 11 and CuO/ZnO/Al ₂ O ₃ catalytic module 12 and so on. The cylinder components include a working cylinder 10 and a reforming cylinder 11. The throttle valve 4 cooperates with the natural gas flow valve 3 to control the air-fuel equivalence ratio in the working cylinder 10 to be greater than 1 to ensure lean combustion. The cylinder head of the working cylinder 10 is provided with a spark plug, and the cylinder head of the reforming cylinder 11 is provided with an ethanol injection valve, and the piston of the reforming cylinder 11 is provided with a CuO/ZnO/Al ₂ O ₃ catalytic module 12 ( The thickness of the module is less than the top dead center clearance to avoid collision). The intake valve of the working cylinder 10 is connected to the mixer 7 through an intake pipe, while the injection valve of the ethanol reforming cylinder 11 is connected to the ethanol storage tank 14 through a supply line. Natural gas, air and hydrogen-rich reformed gas are fully mixed in the mixer 7, and then enter the working cylinder 10 through the intake pipe and intake valve. The heat source of the heat exchanger 2 is provided by the combustion waste gas discharged from the working cylinder, and the liquid natural gas is converted into gaseous natural gas through heat exchange. The buffer gas tank 13 has collection and storage functions. When the engine is in a cold start or low load state, the reforming cylinder 11 cannot produce enough reformed gas, and the buffer gas tank 13 can provide a hydrogen-rich mixture to assist combustion under this working condition.

The cylinder head of the working cylinder 10 is provided with a spark plug, and the cylinder head of the ethanol reforming cylinder 11 is provided with an ethanol injection valve, and the piston is provided with a CuO/ZnO/Al ₂ O ₃ catalytic module 12; the exhaust gas of the reforming cylinder 11 The valve is connected with the turbine and the heat exchanger 2 through pipelines to provide energy for air pressurization and natural gas vaporization. There is no combustion phenomenon in the reforming cylinder 11, and the hydrous ethanol generates a hydrogen-rich mixed gas composed of hydrogen, carbon monoxide and methane under high temperature conditions and the action of a catalyst. A buffer gas tank 13 and a flow valve 15 are provided in the circuit where the ethanol reformed gas leads to the mixer 7 , and the buffer gas tank 13 has the function of collecting and storing the hydrogen-rich reformed gas.

As shown in Figure 1, the air enters the turbocharger 5 through the throttle valve 4, and then enters the mixer 7 after being cooled by the intercooler 6. The liquefied natural gas is supplied by the natural gas storage tank 1, converted into gaseous natural gas through the carburetor 2, the flow rate is controlled by the natural gas flow valve 3, and after entering the mixer 7, it is evenly mixed with air and reformed gas, and then enters the working cylinder. The air-fuel equivalence ratio of the mixture entering the working cylinder 10 is controlled to be greater than 1 through the throttle valve 4 and the natural gas flow valve 3 to ensure lean combustion. Part of the exhaust gas produced by the combustion of the working cylinders leads to the turbocharger 5 to provide energy for the supercharger, and part of it passes to the carburetor 2 to provide heat for the phase transformation of natural gas.

There is no ignition device in the ethanol reforming cylinder 11, an ethanol injection valve is installed on the top of the cylinder head, and a CuO/ZnO/Al2O3 catalytic module with a sponge-loaded structure is arranged on the piston. Through the high temperature environment and the strong turbulent flow in the cylinder, the ethanol generates a mixture of hydrogen, carbon monoxide and the like. The exhaust valve of the reforming cylinder 11 is connected with the buffer gas tank 13 through the exhaust pipe, and the buffer gas tank has the ability to collect and store the mixed gas. A reformed gas flow valve 16 is provided between the buffer gas tank 11 and the mixer 7 to adjust the reformed gas flow according to the engine load. When the engine starts cold, the reaction in the ethanol reforming cylinder is insufficient, and the stored hydrogen-rich mixture can be fed into the mixer 7 to ensure that the natural gas can be burned efficiently even at cold start and low load.

Claims (4)

1. a kind of ethyl alcohol reforms the natural gas engine of auxiliary combustion online, it is characterized in that：Including working cylinder, reformed gas cylinder, Natural gas storage tanks, ethyl alcohol storage tank, turbocharger, mixer, the inlet communication inlet manifold of working cylinder, working cylinder Outlet exhaust main, inlet manifold is connected to mixer, and exhaust main is respectively communicated with the whirlpool of heat exchanger and turbocharger Wheel import, the blower outlet connection mixer of turbocharger, the outlet heat exchanger of natural gas storage tanks, heat exchanger Two outlets are respectively communicated with mixer and air, the inlet communication ethyl alcohol holding vessel of reformed gas cylinder, the outlet of reformed gas cylinder Has the buffering gas tank of collection and the hydrogen-rich reformed airway dysfunction of storage, buffering gas tank is connected to mixer.

2. a kind of ethyl alcohol according to claim 1 reforms the natural gas engine of auxiliary combustion online, it is characterized in that：It reforms Ethyl alcohol injection valve is set at the top of the cylinder cap of cylinder, the CuO/ZnO/Al of sponge supporting structure is set on the piston of reformed gas cylinder₂O₃It urges Change module.

3. a kind of ethyl alcohol according to claim 1 or 2 reforms the natural gas engine of auxiliary combustion online, it is characterized in that： Air throttle is arranged in the compressor inlet of turbocharger, and gas discharge valve is arranged between clarifier and mixer, buffers gas tank Reformate gas stream amount valve is set between mixer, ethyl alcohol flow valve is set between ethyl alcohol holding vessel and the import of reformed gas cylinder.

4. a kind of ethyl alcohol according to claim 3 reforms the natural gas engine of auxiliary combustion online, it is characterized in that：Solar term The synergy of door and gas discharge valve so that the excess air ratio in working cylinder is more than 1；Under cold start-up or underload, The hydrogen-rich gaseous mixture stored in buffering gas tank is passed through mixer by reformate gas stream amount valve.