30 • May/June 2019 Bioenergy Insight

Bioenergy biomass by-product

The most common briquettes in the UK and Europe are either mechanical, hydraulic or screw extruded briquettes, each with their own advantage.

Mechanical press briquettes

Briquettes made on a mechanical press are the most popular in the UK, typically coming in cylindrical or cuboid varieties. The briquettes are dense, burn well and almost look like firewood. The diameter can be from 60 to 100mm. Other advantages are a fairly high capacity, and low production costs, and particularly low power consumption. The briquettes are used in homes, gardens, restaurants and wherever you would need firewood.

Screw press briquettes

These are high quality briquettes with very high density. This briquetting process is more delicate and requires homogenous raw material with fine particles and moisture content from 6 to 8%. If these requirements are met, these state of the art briquettes will burn longer than most other alternatives because of the higher density and are proving popular in the UK. They are normally produced as cuboids with dimensions of 55 by 55mm, 65 by 65mm and 200 by 200mm. These briquettes can be carbonised and sold as charcoal, but are typically used

as consumer briquettes, as logs, for fireplaces and wood-burning stoves.

Hydraulic press briquettes

These briquettes ignite easily and burn well. They are a uniform, rectangular size that makes them easy to store and are typically used as consumer briquettes for fireplaces and wood-burning stoves. The briquettes have a lower density, slightly below 1.0 g/cm3, which gives a shorter burn as compared with the density of mechanical press briquettes, which are between 1.0 and 1.2 g/cm3, and the density with the screw press briquettes can be up to 1.3 g/cm3.

Mechanical, hydraulic and screw press briquette

Producing briquettes for increasing applications while meeting demand and maintaining standards

Briquetting: A growing trend for domestic fuelS ince the beginning

of civilization, humans have tried to store and intensify energy.

Methods used were as simple as drying, bundling and bailing to compact loose combustible material for fuel making purposes.

Modern briquetting is simple, but only because of the tremendous know-how accumulated over time that the briquetting press manufacturers have put into numerous complex technologies. Today, most briquettes are made on technically advanced and highly automated mechanical,

hydraulic or screw extruder briquetting lines. Seen in a historical context, briquetting on a commercial level is a relatively new phenomenon with the first industrial plants dating back to the second part of the 19th century.

A biomass briquette is

typically made from biomass by-products like sawdust, wood waste or agricultural leftovers. The machines compress the biomass making

reconstituted logs that can replace firewood or coal. This product first emerged in developed countries, but a refined version of the

The packaging machine lining up cylindrical briquettes as they enter

Bioenergy Insight May/June 2019 • 31

biomass by-product Bioenergy product was developed in the industrialised world. The use of briquettes, mainly in industry, was revitalised during the period of high energy prices in the 1970s and early 1980s, especially in Scandinavia, USA and Canada. Since the 1980s to today, briquettes have slowly been gaining more popularity among homeowners and now most of the world is familiar with them.

Growing European demand

Recently, focus on renewable energy has grown and the applications for briquettes have grown concurrently. Consumers require green energy that is economically competitive and convenient at the same time, and on both aspects, briquettes prevail over traditional domestic fuel sources. Therefore, briquetting today receives deserved

attention, and is becoming a real alternative to conventional firewood and coal. Briquettes simply burn hotter and cleaner,

are cheaper to buy and much easier to store and handle. Briquettes deliver around 50% more heat for each euro

spent than logs. Apart from being clean and dry, another environmental benefit is that briquettes are often made from

The world’s largest briquetting plant was built in Germany, 2013

32 • May/June 2019 Bioenergy Insight

Bioenergy biomass by-productwaste material that would have otherwise been sent to landfill. Consumers continue to discover these advantages, and over the last two years in particular, interest has been growing; prices and demand are unusually high, and suppliers are struggling to keep up with the progressive market.

UK briquettes

The market in the UK is no exception. During the last couple of years there has been a misbalance between demand and supply of briquettes. The suppliers have simply not been able to meet the volume required and consequently prices have increased. Briquette dealers all over the UK have imported briquettes from Eastern Europe, and many companies need more local supply options guaranteeing consistent delivery.

Another circumstance that

helps to accelerate the trend of briquetting is the renewed focus on air pollution in big cities such as London. Experts say that burning of wet or unseasoned wood and smoky solid fuels is a big problem; in winter, wood burning can contribute up to 10% of local emissions in London. To improve air quality, an important step is making sure only the cleanest domestic fuels are available for sale. Wet wood results in darker smoke and harmful particles. Consequently, it has been politically discussed to ban wood with moisture content higher than 20%. Also, stove manufacturers recommend

users only burn wood with moisture content less than this, but logs sold in the UK generally have higher levels of moisture — 20% in well-seasoned wood, and up to 50% in other cases. With briquettes however, most have moisture content of 10% or less, meaning they burn better and cause fewer chimney and flu problems. Customers start buying the briquettes on the advice of their chimney sweep, because they are much cleaner burning and the tar- associated problems with unseasoned firewood can be avoided.

Briquettes in the future There are no indications that the enthusiasm for briquettes will disappear in the future. On the opposite, the interest and market share increase every

day. Growing environmental consciousness means that climate conscious consumers require clean, green and efficient fuel for their homes. This combined with growing awareness that briquettes can deliver more heat for money, means that briquettes are impossible to ignore and the trend of briquetting is here to stay.l

For more information:Esben Mikkel Vestergaard is regional sales manager at C.F. Nielsen. Visit: www.cfnielsen.com

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