Gas Engine Lean Gas Operation Preheating
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Solution Overview
Problem
Conventional gas engines are not suitable for operating with lean gases that have a methane content of less than 20% by volume, as they cannot form a sufficiently ignitable and energy-rich mixture, leading to inefficiencies and waste in utilizing gases like mine gas and sewage gas.
Innovation Solution
Preheating the mixture of lean gas and inlet air to a temperature between 120° C and 150° C before entering the gas engine, using a tandem Venturi mixer to improve the mass ratio and ignitability, and potentially preheating the air flow to 35° C to 50° C before the Venturi mixer, along with direct injection and precompression of the lean gas, to enable operation with low-calorific lean gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional gas engines operate with lean gases containing less than 20% methane, then the engine cannot form a sufficiently ignitable and energy-rich mixture, but preheating the mixture to 120-150°C enables operation with such low-calorific gases
Solution Approach 1:
The invention changes the temperature parameter of the fuel mixture from ambient temperature to 120-150°C before entering the engine. This parameter change increases the vapor pressure and energy content of the lean gas mixture, making it sufficiently ignitable and energy-rich for engine operation despite the low methane content below 20%.
2Adaptability or versatility
If the mixture is preheated to 120-150°C before entering the gas engine, then operation with low-calorific lean gas is enabled, but energy is consumed for preheating
Solution Approach 1:
The invention combines the preheating function with the existing exhaust gas system. Exhaust gases that would otherwise be wasted are redirected to preheat the fuel mixture, merging two functions (exhaust disposal and fuel preheating) into a single integrated system that converts waste energy into useful preheating energy.
3Reliability
If a tandem Venturi mixer is used to improve mass ratio and ignitability, then mixture quality is enhanced, but device complexity increases
Solution Approach 1:
The invention segments the mixture formation process into two separate Venturi mixers arranged in series (tandem configuration). The first Venturi mixer performs initial mixing of lean gas and air, while the second Venturi mixer completes the mixing process. This segmentation allows each mixer to be optimized for its specific function, improving overall mixture quality and ignitability despite the increased device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the operation of conventional gas engines with lean gases having less than 20% methane content, allowing for the utilization of otherwise wasted gases in generating electrical energy while maintaining efficiency.
Implementation Method 1
The lean gas is mixed with an inlet air stream in at least one Venturi mixer to form a mixture
Implementation Method 2
the mixture is preheated to a temperature between 120° C. and 150° C. before it enters the gas engine
Implementation Method 3
preheating the air flow to 35° C to 50° C before the Venturi mixer
Data Source
Figure 1
AI summary
The invention relates to a method for operating a gas engine (1) with a low-calorific gas containing less than 20% methane by volume, wherein the low-calorific gas is mixed with an intake air stream in at least one Venturi mixer (8) to form a mixture, and wherein the mixture is supplied to the gas engine (1) as fuel. According to the invention, the mixture is preheated to a temperature (ϑ1) between 120 °C and 150 °C before entering the gas engine (1).