KILNS Q&A

KILNS QUESTIONS AND ANSWERS

 

Click a question to reveal the answer:

What are the key features of the SuperChar 100?

  • Easy to Use: This is a simple device that two people can set up and operate on flat ground away from roads and settlements.Fast and Flexible: A batch of biochar can normally be produced within 24hrs from logs of different sizes.High Yields: The unit produces biochar slowly at low temperatures (450-500C) resulting in yields of 100kg to 150kg of biochar from approximately 500kg of feedstock (20-30%).Green Wood: The resulting biochar can easily be crushed, or ground in a garden shredder, for instant use as a soil improver.
  • Biochar for the soil: The biochar produced by the SuperChar 100 is ideal for use as a soil amendment.
  • Lower emissions: The SuperChar 100 re-circulates and burns off harmful greenhouse gases (methane and nitrous oxide) resulting in lower emissions from your biochar production process.

Can the SuperChar 100 be easily transported and delivered?

Yes, the SuperChar 100 is easy to transport in the back of a pick up and can also be moved by a tractor with a forklift.

Can biochar be added to the soil straight away?

Well-made biochar, which has been processed into smaller particles, can be applied directly to the soil but activating biochar with wormcasts and mycorrhizal fungi (as with our GroChar range) gets it to work even faster and more efficiently for optimum plant health.

What kind of biomass can be used in the Carbon Gold kilns?

Any dry uncontaminated organic woody material, from small branches to sawn logs, can be used to create biochar. It is important not to use feedstock that may have been contaminated with heavy metals such as old painted wood, which may contain lead, if the resulting biochar is being used to improve soil fertility.

Does pyrolysis emit some pollutants?

Biochar production does generate some pollutants – such as tars, phenols, carbon dioxide and nitrous oxide – but at far lower levels than would be emitted if the woody biomass was simply burnt. Carbon Gold has developed kilns that minimise these pollutants.

Can the kilns be transported abroad as well as in the UK?

Yes, for example, we supplied a number of inexpensive kilns to organic cacao farmers in Belize, who grow cacao for Green & Black’s.

What is Carbon Gold?

Carbon Gold is a biochar company based in Bristol, UK

What does Carbon Gold do?

Carbon Gold produces a range of biochar-based soil products. The company also advises on the creation and implementation of biochar production systems.

When was Carbon Gold founded?

Carbon Gold was founded in 2007 by Craig Sams who is co-founder of Green & Blacks chocolate and a range of other successful ethical enterprises including popular health food brand Whole Earth and Judges Bakery in Hastings where he lives.

How easy is it to make biochar?

Humans have been making biochar for thousands of years; the basic production process is not difficult. Carbon Gold’s technology has been developed to ensure that the process is as efficient as possible.

What is Carbon Gold’s mission?

At Carbon Gold our mission is to get as much biochar in the ground as possible for both the health of our climate and health of our soils.

Who is Carbon Gold’s product range aimed at?

Carbon Gold’s products can be used by anyone with an interest in improving the health and fertility of their soil.

What sizes do Carbon Gold’s products come in?

According to the various needs of our customers, the products are sold in a range of sizes from easy to carry bags, buckets and tubes to bulk bags for professional growers or those with large growing areas.

What’s in the Carbon Gold product range?

Our range comprises of six products, all manufactured here in the UK. They combine the traditional benefits of biochar with the latest in sustainable soil science:

  • Soil Improver, made up of biochar plus mycorrhizal fungi, seaweed, and worm casts.
  • Fertiliser, a natural mix of equal parts nitrogen, phosphate and potash, all from plant sources, with the addition of our unique biochar Soil Improver
  • All Purpose Compost & Seed Compost, made up of coir plus our unique biochar Soil Improver
  • Tree Soil Improver – our biochar Soil Improver optimised for use on trees
  • Tree Fertiliser – our biochar Soil Improver blended with potassium phosphite

To buy the range online please click here.

How is Biochar good for my plants?

In short, biochar improves soil structure, encourages beneficial fungi and bacteria and enhances nutrient retention:

  • Biochar provides a perfect habitat for mycorrhizal fungi to grow and flourish. These fungi colonise the pores of biochar particles, which protects them from predators – tiny nematodes, mites and protozoa. This leaves the fungi able to feed nutrients to ‘their’ plant and protect it from disease.
  • Fewer nutrients are lost from the upper levels of biochar-enriched soils. Biochar has a mild cation exchange capacity which enables it to stop minerals from leaching out but still keeps them available to the mycorrhizal fungi and therefore to the plants.
  • Biochar increases the waterholding capacity of soil at the same time as helping with drainage. Paradoxical but true. The porosity of biochar means it is like millions of tiny sponges in the soil, retaining moisture. This also helps keep fungi and bacteria alive during dry spells.
  • Biochar neutralises or maintains the pH of soil, reducing the tendency to acidification that vegetable growers seek to avoid.
  • Biochar helps fix carbon from compost in soil, building humus and organic matter.
  • Biochar is long-lasting. It is a stable form of carbon that can stay put in the soil for many years. In Brazil, where it was used by great Amazonian civilisations, biochar-rich soils have been carbon-dated to 4000 years ago.

How do the other ingredients in Carbon Gold product range help my plants grow?

  • Mycorrhizal fungi and wormcasts help to activate the biochar and the seaweed provides valuable trace elements:
  • Mycorrhizal fungi maximise the take-up of nutrients by plant root systems.
  • Wormcasts provide viable Actinomycetes soil bacteria which decompose a wide array of substrates and are responsible for the healthy ‘earthy’ smell of freshly turned soil.
  • Kelp seaweed extracts promote vigour
  • Potassium Phosphite acts as a fertiliser in the product blend

How do I use the Soil Improver?

The Soil Improver is a versatile product. Here are a few ways it can be used:

  • Give a boost to pot plants, window boxes and hanging baskets by adding a handful or two to the existing compost.
  • Improve the vitality of established trees, shrubs or perennials by top dressing around the base of the plant and loosely incorporating it into the soil.
  • Add a generous sprinkling to your personal compost mix to accelerate break down and improve the structure.
  • Use as an additive to your usual seed compost to improve nutrient uptake and plant health.
  • Use a sprinkle in each hole when planting out to minimise transplant shock for vegetable plugs, shrubs and trees.
  • Use instead of the peat component in John Innes compost mixes.
  • Can also be broadcast over large areas of soil, such as an allotment plot, as an annual soil improver.

To read more about how to use the GroChar Soil Improver please click here.

To watch Alys Fowler demonstrating how to use it please click here.

Can I buy a Carbon Gold biochar kiln?

Yes, the smallest of our kilns, the SuperChar 100 is available for sale.

What research supports the view that adding biochar to our soils is good for the climate?

Friends of the Earth published a report called ‘Negatonnes’ (Sept 2011) in which they recognise the importance of biochar as a carbon dioxide reducer. Chris Goodall, author of ‘Ten Technologies to Save the Planet’, recommends biochar as a useful and important way to help reduce atmospheric concentrations of carbon dioxide. Goodall is supported by James Lovelock, originator of the Gaia theory, who said: “There is one way we could save ourselves and that is through the massive burial of charcoal. It would mean farmers turning all their agricultural waste – which contains carbon that the plants have spent the summer sequestering – into non-biodegradable charcoal, and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the carbon dioxide down quite fast.”

How do I use the Fertiliser?

GroChar Fertiliser is in an easy to use, all-natural pelleted form and delivers superb results without any chemical additives. It is ideal for sprinkling around flowers, vegetables, fruits, shrubs, borders, and houseplants and adding a generous handful or two to boost pots & containers, hanging baskets & window boxes. It is packed with optimum amounts of nitrogen for overall growth and green leaves; phosphate to support healthy root growth; and potash for abundant flowering and fruiting. The addition of biochar helps keep nutrients in the top level of soil, making them readily available to plants.

To read more about how to use the GroChar Fertiliser please click here.

How do I use the Carbon Gold Composts?

All-purpose compost:

Use it for general indoor and outdoor use in containers, hanging baskets, potting on and planting directly into garden soil.

Seed compost:

Use it to get your seeds off to a strong start.

In short, you can use our all-purpose and seed composts just like you would any other composts. The only difference is that, due to the unique water-holding properties of coir and biochar, you have to water less often.

 

To read more about how to use the GroChar Compost please click here.

What is coir?

Coir is made from coconut husks. The coir used by Carbon Gold is organically certified by the Soil Association.

How much do Carbon Gold’s products cost?

To view all product details including prices, please see our shop.

What is biochar?

Biochar is a form of charcoal that has been used for millennia to improve soil nutrition and growing conditions. It can be made from any woody biomass that has been charred at a low temperature with a restricted supply of oxygen, a process called pyrolysis. As well as being a useful soil amendment, biochar can reduce atmospheric concentrations of carbon dioxide when buried in the ground.

How is biochar different from barbeque charcoal?

Biochar is made at lower temperatures than charcoal, which results in a higher carbon content. It doesn’t need to be made from hardwoods, as barbeque charcoal does, and can be used in much smaller pieces or powder – known as ‘fines’ – rather than lumps.

Is biochar a new product?

Knowledge of biochar and the benefits of adding it to soil have been around for millennia. Studies of soil at sites throughout the Amazon Basin suggest that ancient Amazonian civilisations made a primitive type of biochar and added it to their soils to help grow their food. The result was a rich and fertile black earth – or ‘terra preta’ – with a high carbon content, which is still evident today.

Why have I not heard of biochar before?

Biochar is not commonplace in British horticulture but it has been a by-product of traditional woodland management in the UK for many years, along with charcoal making.

Does the Department for Environment, Farming & Rural Affairs (Defra) advocate the use of biochar?

Defra set up the Sustainable Growing Media Task Force in 2011 to help them in their effort to reduce the use of peat in both professional horticulture and amateur gardening. The task force put together their recommendations in July 2012 and as a result the government announced a number of measures in January 2013 that they would take to support the recommendations. This included £1-million toward research into alternatives to peat. Biochar is one of the amendments to growing media being considered as an alternative to peat.

Why is adding biochar to our soils good for the climate?

Photosynthesis puts carbon from the atmosphere into biomass. That carbon returns to the air when the biomass rots or burns, but much of it can be permanently stored as biochar in the ground. Biochar is a very stable form of carbon. It also reduces soil emissions of nitrous oxide, a greenhouse gas 300 times more damaging than carbon dioxide. It is not a silver bullet but it represents a powerful tool to help reverse the process causing climate change.

Surely if global warming is to be prevented we need to cut emissions on a larger scale?

Biochar can play an important part in the battle against climate change but it cannot be expected to compensate for increasing emission levels. It is vital that everybody plays a part in reducing energy consumption.

How much carbon does biochar contain?

It varies according to production methods, but is typically between 70% and 90% carbon.

How do you know that the carbon in biochar will stay in the soil?

Carbon is chemically stable, it does not react readily with water or atmospheric oxygen, and so once in the soil it tends to remain there. The carbon in ‘terra preta’ soils has been subject to some of the highest rainfall on earth and it is still present after 4000 years.

Where does Carbon Gold’s biochar come from?

We source as much of our biochar as possible from UK-based producers. However UK-sourced biochar is in short supply so the remainder of what we need for our products comes from outside the UK. All our biochar is sustainably sourced and certified for use in organic growing systems.

What is the scale of Carbon Gold’s biochar production?

Biochar can be produced by large plants capable of turning out 10,000 tonnes per year or as a cottage process producing just a small amount of biochar each day. Carbon Gold kilns only operates at the smaller end of this scale.

What do you use to produce biochar?

Carbon Gold has developed a series of kilns for the optimum production of biochar, which are economical, efficient and easy-to-use.

SuperChar 500

Burn time – around 8 hours
Moisture content – up to 60%
Feedstock size – rice husk and wood shavings up 30cm length logs
Feedstock type – most types of biomass
Feedstock volume – two x 6m3
Fuel source – dry woodchip and wood pellets
Char yield – up to 800kg per burn (400 per 6m3 chamber)
Infrastructure used – 4 electric fans and a generator (provided with the kiln)

The SuperChar 500 is a versatile commercial kiln that is capable of both drying and charring a wide range of feedstocks. The kiln is built in to a 20ft container for the ease of transport. The kiln consists of two kiln bodies and an external combustor, there is 6m3 capacity for feedstock in each kiln body. The kiln can run in three ways:
1. Drying – Both kiln bodies are filled with wet feedstock which is air dried using wood chip in the combustor.
2. Charring 1 – One kiln body is filled with dry material, such as reed bundles, to be charred. Gas produced during the pyrolysis is used to fuel the combustor and the excess heat is used to dry the material in the other kiln body.
3. Charring 2 – Kilns are alternatively filled with wet material which is initially dried using the excess heat from the other kiln body and is then charred and provides heat for the drying of the refilled other kiln body.

The kiln can process a wide range of feedstocks including woodshavings, woodchip, logs, rice husks, coffee husks, rush and wetland reed. The kiln can process feedstocks up to 60% moisture. The kiln requires dried woodchip to run as the fuel source for the initiation of the process, this is fed automatically into the combustor until the charring material is up to temperature and releasing sufficient syngas.

The burn time varies significantly, the length depends on the moisture content, type and size of the feedstock used. The length of a burn depends which function you are running under as well as the feedstock type, size and moisture content.

The SuperChar 500 kiln is a versatile kiln which can be used for many functions. Carbon Gold can customise the 500 kilns to suit customers’ needs. There are lots of agricultural processes where products need to be dried whilst leaving a low grade biomass in the waste stream. Through using a kiln that can process the waste low grade biomass to biochar whilst utilising the waste heat from pyrolysis, processing plants have the ability to have a sustainable waste management system whilst have low cost energy for drying functions.

SuperChar 500
Patent pending, all rights reserved.

SuperChar 100 Mk I

Burn time – around 8 hours
Moisture content – up to 40%
Feedstock size – logs, up to 20cm in length and 10cm in diameter
Feedstock type – Wood
Feedstock volume – 1.5m3
Fuel source – logs, up to 15cm in length and 5cm in diameter
Char yield – up to 100kg per burn
Infrastructure used – handheld leaf blower (provided with the kiln)

The SuperChar 100 Mk I is a simple, easy to use kiln. It has a cylindrical kiln body which is 4ft high and 5ft in diameter. The kiln body has an internal combustor which hangs from the lid; this leaves space for 1.5m3 of feedstock. It takes approximately 8 hours for a single burn, this does depend on the moisture content, type and size of the feedstock used.

After a burn the kiln needs to be left over night to cool prior to unloading. The kiln is loaded from the top, the kiln comes with a hand driven winch to remove the lid for loading. After a burn the kiln is left overnight prior to unloading through a door at the bottom. A single burn can produce up to 100kg of biochar.

The kiln runs with a two stage cycle, the first stage is the drying of the feedstock whilst the second is the charring of the feedstock. The kiln acts as a steam drier during the first stage, the kiln relies on natural convection currents throughout the burn cycle. During the drying stage small logs are used as the fuel source to dry the feedstock. The second stage of the burn is the pyrolysis of the feedstock, the temperatures are raised to around 450°C, the feedstock releases syngas. This syngas is then burnt in the kiln to maintain suitable charring temperatures.

The kiln is transportable on a small trailer (although a fork lift is needed to lift the kiln). The kiln therefore does not need planning permission as it is a transportable unit. It does produce some steam and smoke and so it is advisable to locate it away from buildings and people. The kiln does not need electricity to run, it comes with a leaf blower which is used to supply air to the internal combustor.

The SuperChar 100 Mk II kiln is a more sophisticated version of the 100 Mk I, the kiln is capable of processing are far wider range of feedstocks. The Mk I and the Mk II produce the same volume of biochar per burn, the Mk I kiln relies on the natural convection of heat within the kiln to evenly char the feedstock whilst the Mk II has a forced circulation. It is due to this forced circulation that the Mk II is capable of charring such a wide range of feedstocks at such high moisture contents.

kilns7i

 

SuperChar 100 Mk II

Burn time – around 8 hours
Moisture content – up to 60%
Feedstock size –  wood shavings or rice husk, up to 30cm length logs
Feedstock type – most types of biomass
Feedstock volume – 1.5m3
Fuel source – logs, up to 15cm in length and 8cm in diameter
Char yield – up to 100kg per burn
Infrastructure used – 3 electric fans and a generator (provided with the kiln)

The SuperChar 100 Mk II is a small scale biochar kiln capable of processing a wide range of different materials. The kiln has a kiln body which is 4ft high and 5ft in diameter. The kiln body has an internal combustor; this leaves a feedstock capacity of 1.5m3. The kiln has been tested on a wide range of feedstocks including woodshavings, woodchip, logs, rice husks, coffee husks, rush and wetland reed. The kiln can process feedstocks up to 60% moisture.

The length of a burn time varies significantly and depends on the moisture content, type and size of the feedstock used. Some burns have been as quick as 3 hours whilst some have taken as long as 10 hours. After a burn the kiln needs to be left over night to cool prior to unloading. The kiln is loaded from the top and comes with an electric winch to remove the lid for loading. Once the kiln has been left to cool overnight after a burn it can be unloaded through a door at the bottom. A single burn can produce up to 100kg of biochar.

The kiln runs with a two stage cycle. The first stage is the drying of the feedstock whilst the second is the charring of the feedstock. The kiln acts as a steam drier during the first stage. The kiln has 3 electric fans which force the steam through the feedstock. A key factor as to whether a feedstock is suitable for use in the kiln is the porosity of the material. The fans must be able to force the steam to flow through the material. During the drying stage small logs are used as the fuel source to dry the feedstock.

The second stage of the burn is the charring of the feedstock. The temperatures of the feedstock is raised to around 450°C. The feedstock releases syngas during the pyrolysis process – this syngas is then burnt in the kiln to maintain suitable charring temperatures.

The kiln is transportable on a trailer (although a fork lift is needed to lift the kiln). The kiln therefore does not need planning permission as it is a transportable unit. It does produce some steam and smoke and so it is advisable to locate it away from buildings and people. The kiln does need electricity to run however it is supplied with a suitable generator.