Biogas Engine Intake System Dew Point Control
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Solution Overview
Problem
Biogas engines face issues with condensation and tar deposition when the mixed gas containing biogas and air is introduced to the combustion chamber at temperatures below the dew point, leading to potential component damage and malfunction, particularly in cold regions.
Innovation Solution
A biogas engine configuration that includes a biogas cooling unit to adjust the biogas temperature and a heat exchanger to heat the air before mixing, ensuring the mixed gas temperature remains at or above the dew point, using engine waste heat or a supercharger to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If biogas is cooled to the dew point and mixed with cold air, then cooling efficiency is improved, but condensation and tar deposition occur causing component rust and malfunction
Solution Approach 1:
The patent applies preliminary action by heating the air before mixing with biogas. The air intake passage includes a heating section that pre-heats the air using engine waste heat, ensuring that when the cooled biogas mixes with the air, the mixed gas temperature remains above the dew point, preventing condensation and tar deposition before they can occur in the combustion chamber
Solution Approach 2:
The patent converts the harmful effect of engine waste heat into a beneficial heating source. The waste heat that would otherwise be discarded is utilized to heat the intake air, preventing condensation issues while also improving overall system efficiency by recovering energy that would be lost
2Reliability
If heating means is added to prevent condensation, then component reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by integrating the heating function into the existing air intake passage. The heating section serves dual purposes: it heats the air to prevent condensation while also utilizing engine waste heat that would otherwise be discarded. This eliminates the need for separate heating devices and reduces overall system complexity
Solution Approach 2:
The system applies self-service by using its own waste heat to solve the condensation problem. The engine's waste heat, which is already present in the system, is redirected to heat the intake air, making the system self-sufficient and eliminating the need for external heating sources or additional energy input
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
Prevents condensation and tar deposition, thereby avoiding component damage and ensuring smooth operation of the biogas engine even in cold regions by maintaining the mixed gas temperature above the dew point.
Implementation Method 1
a heat exchanger arranged between a pipe for engine waste heat and the intake path is provided in the intake path and upstream of the mixing part with respect to an intake direction of the air, the heat exchanger serving as a heating unit for heating the air sucked through the intake path
Implementation Method 2
the biogas cooling unit comprises a gas cooler for washing the biogas with a washing liquid and cooling the biogas with a cooling water
Implementation Method 3
a mixing part is provided in an intake path through which the air is taken in, the mixing part mixing the air and the biogas whose temperature is adjusted by the biogas cooling unit
Implementation Method 4
If a mixed gas containing a biogas and air has a temperature below the dew point, a water vapor contained in the mixed gas is condensed to generate condensed water (condensation)
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A biogas engine that uses as a fuel a biogas produced by a biogas-producing gasifier and combusts a mixed gas containing the biogas and air in a combustion chamber includes: a biogas cooling unit provided in a biogas supply path extending from the gasifier to the combustion chamber, the biogas cooling unit adjusting the temperature of the biogas; a mixing part provided in an intake path through which the air is taken in, the mixing part mixing the air and the biogas whose temperature is adjusted by the biogas cooling unit; and a heating unit provided in the intake path and upstream of the mixing part with respect to an intake direction of the air, the heating unit heating the air sucked through the intake path so as to keep the temperature of the mixed gas at or above the dew point.