The terms rich-burn and lean-burn simply refer to the air-to-fuel ratio, or how the engine burns fuel. Excess fuel in the combustion chamber during combustion characterizes a rich-burn engine, while excess air in the combustion chamber characterizes a lean-burn engine.
In this reading, we’ll explore what rich burn and lean burn engines are, their applications, working, and differences.
Rich Burn Engines:
A rich-burn natural gas generator could be the answer if you’re seeking a clean, dependable alternative to diesel power. These generators are ideal for any application that requires a long run time, low exhaust or noise emissions, or where on-site fuel storage is limited, such as rooftop installations.
Using a gas supply to power your facility can also save you a lot of money, and any CAPEX on equipment can be swiftly recovered.
Commercial, retail, and healthcare facilities benefit from rich-burn gas generators. Significant cost savings; a stable, safe electrical power supply; proven technology; and ease of installation — there is a minimal equipment footprint, and you can essentially plug in and go, including the gas supply!
Transient load response is more important than fuel efficiency in applications where rich-burn gas engines are used. Because of their rapid start and transient performance, they are commonly used in prime and emergency standby applications.
These engines are best suited for high-power applications with fluctuating loads. Rich-burn gas engines have a higher AFR because the fuel-to-air ratio is higher. It’s a fuel-rich concoction. (λ) equal to 0.995 is commonly used in rich-burn engines.
Rich-burn generators have the lowest emissions of any combustion engine generator because they use a three-way catalyst. Rich-burn engines can take a block load and run at a wide range of loads.
Rich-burn engines with a high power-to-weight ratio can provide competitive fuel efficiency in energy management applications with lower running hours. When it comes to part-load operations, this is especially true.
Lean Burn Engines:
High electrical efficiency is connected with lean-burn gas engines. They are often utilized for baseload and cogeneration facilities due to their efficiency benefit.
Lean-burn gas engines have a greater air-to-fuel ratio (AFR) than is required to burn all of the fuel, resulting in a ‘fuel-lean’ combination. Lean-burn engines use (λ) values ranging from 1.5 to 2.2.
If your company uses a lot of electricity and is currently connected to the grid, this technology could be excellent for you. Some products offer this equipment as a capital buy or a fully-funded PPA solution, allowing you to take control of your energy and create your own continuous power onsite utilizing innovative lean-burn gas generators, which are installed behind the meter.
This fully funded gas-to-power energy system will drastically lower your energy expenditures in a short period of time.
This solution is excellent for facilities that use a lot of electricity (200 kW or more), such as food and beverage manufacturing or large-scale industrial manufacturing.
The lean-burn solution provides budget stability while lowering your reliance on the grid and providing a reliable, secure supply of electrical power.
Difference between rich-burn and lean-burn engines
Emergency standby generators account for over 80% of the global generator market. The generator’s ability to start and accept load in a life-safety application can be the difference between life and death.
As a result, rich-burn engines have been demonstrated to give considerable advantages over lean-burn engines in standby applications:
- Provide better generator starting and load acceptance for standby use on a regular basis.
- Because of the AFR’s increased relative energy content, it’s great at picking up block loads.
- Because of their low turbocharging requirements, they can deliver rated output power at greater altitudes and in hotter ambient temperatures.
- Due to the fundamental properties of the rich-burn combustion event, it has a higher tolerance for fluctuations in fuel quality and fuels with a lower methane number.
Lean-burn technology, on the other hand, has poor block-loading capacities and performs poorly at higher temperatures and altitudes. Most lean-burn engines also require exhaust after-treatment using selective catalytic reduction (SCR), which is expensive and time-consuming to maintain.
Local pollution restrictions may enable lean-burn engines to operate without an SCR, but an oxidation catalyst to regulate carbon monoxide (CO) may still be necessary. However, on vehicles, lean-burn engines offer many benefits; on standby applications, rich burn is good.
Conclusion
The terms rich-burn and lean-burn simply refer to the air-to-fuel ratio, or how the engine burns fuel. Excess fuel in the combustion chamber during combustion characterizes a rich-burn engine, while excess air in the combustion chamber characterizes a lean-burn engine.