Recovering waste heat from a biogas fuelled gen-set

Biogas is becoming increasingly popular for fuelling generating sets. But why only generate power when you can recover heat too?

As a fuel, Biogas has much to recommend it.

It’s a renewable fuel produced by breaking down organic matter through the Anaerobic Digestion (AD) process. It  reduces the amount of waste being sent to landfill, and helps control the emission of Methane gas to the atmosphere (Methane is significantly more damaging to the environment than CO2). Biogas is also a suitable fuel for engine powered gen-sets and is carbon neutral.

So it’s no surprise that Biogas is being widely used to generate energy as the world seeks to reduce its reliance on fossil fuels to reduce CO2-emissions.

If the story ended there, it would be a good one; but it would be only half the story, because generating sets creating electricity are generally inefficient. Only around 30% of all fuel energy that goes in to the generator gets converted to power. Nearly 50% is converted to heat and lost to atmosphere. Just by recovering the heat energy from the engines exhaust stream provides an additional energy source – at no additional cost in terms of fuel required!

So why not recover this valuable energy source? One of the reasons may be the fuel itself. Biogas is an extremely aggressive fuel and requires careful control of the exhaust stream gas temperature. If the system is overcooled, it can create corrosion in a fabricated carbon steel components, such as exhaust gas heat exchangers, leading to premature failure and the expense of replacing the unit.

The good news is that Bowman exhaust gas heat exchangers, being made entirely of 316L stainless steel, offer a long life solution for recovering waste heat from Biogas, due to the superior material specification and quality of the manufacturing process.

Manufactured in the UK, every component is designed for longevity and durability, even when used with aggressing fuels such as Biogas and consequently Bowman exhaust gas heat exchangers offer much longer service life due to the quality of their construction.

For example, the cooling tubes undergo a two stage installation process ensuring they are permanently secured in the tube plate – first they are roller expanded on to the tube plate and then automatically welded into position, creating a secure weld that is totally consistent across every tube in the heat exchanger. All end cover flanges and shell side flanges are PN6 to BS EN1092 for ease of installation

Bowman exhaust gas heat exchangers are also easy to clean – an important consideration when using a fuel like Biogas, where residues can remain after combustion. They’re also available in a range of sizes and specifications to suit applications from 16 kW to 1 MW, whilst computer aided selection software enables Bowman to recommend the right specification for each application.

The quality and performance of Bowman exhaust gas heat exchangers, has already led to them being selected by a number of AD plants, to replace the failed units originally supplied by others. Their compact design enables them to be easily retro fitted to existing plant, making Bowman units a popular choice for Biogas replacement.

For further information, download the brochure or contact the technical sales team on +44 (0) 121 359 5401 or email [email protected]