Using Renewable Feedstocks in Chemistry

Kate Onissiphorou

by Kate Onissiphorou

15th June 2022

Many aspects of the chemical manufacturing industry have already integrated sustainable, environment-friendly practices. In fact, using renewable feedstock in chemical manufacturing is one of the twelve principles of green chemistry.

As the name implies, a renewable resource can be used several times without being significantly depleted. It can also be replenished quickly without the need for complex industrial processes. The electricity from solar panels, for instance, is renewable because as long as the sun exists, electricity can always be generated.

Likewise, when it comes to industrial-scale chemical manufacturing, a renewable feedstock is something that can be easily regenerated and is not significantly depleted. Biomass is an excellent example of a renewable source of feedstock. It’s both cost-effective and efficient, especially in the long term.

What is renewable feedstock in chemistry?

A chemical feedstock is simply a raw material that’s necessary to produce or manufacture other chemicals or materials. For example, carbon dioxide is a feedstock used by plants in photosynthesis to produce sugar and maintain cellular functions. Another type of feedstock is petroleum, which is commonly used to produce fuel, plastics and rubber. 

The problem with the majority of feedstocks used in manufacturing is that they’re non-renewable. This means they’re continually being used without being replenished. 

Conversely, renewable feedstocks can be easily replaced without being significantly depleted. They’re also replenished at a much faster rate, or at least as quickly as they’re being consumed. 

Petroleum, for example, takes millions of years to form, whereas biomass feedstocks, such as manure from livestock farms, are readily available. Moreover, biomass feedstocks don’t have to be extracted via destructive processes like mining. Compared to petroleum-based feedstocks, they also require a small fraction of investment to obtain and process.

A biogas plant located behind a rape field

Using renewable feedstocks in chemical manufacturing can help to minimise the impact on the environment, while also reducing production costs and increasing the return on investment. Many countries also provide incentives to corporations that use renewable feedstocks in their chemical manufacturing.

What makes feedstock sustainable?

A feedstock is considered sustainable if it can be replenished faster than it can be depleted, or at least as fast as its consumption rate. In other words, the feedstock must be renewable.

Crucially, it must be easily replaced without reducing the overall supply. For example, cement is not a sustainable feedstock because it’s made from rock and mineral sources like limestone that need to be mined. Once a rock is hauled out from a quarry, no new rocks will grow in its place.

Examples of renewable feedstocks

Water

As a universal solvent, water has a central role in chemistry. It’s the main feedstock in many chemical manufacturing processes; without it other chemicals may not readily react or be converted into other substances.

Although some food products, such as dried fruits, need to be hydrated, all beverages have water in them. Most canned goods and preserved food products also contain water. Water is a renewable feedstock because it’s naturally recycled through atmospheric processes.

Hydrogen

As the fuel of stars, hydrogen is the most abundant element in the known universe. However, it’s relatively rare on earth in elemental gas form, accounting for just 0.000055% of the earth’s atmosphere. Hydrogen can be commercially produced in several ways, including from natural gas, crude oil, or via electrolysis. 

When oxygen and hydrogen are mixed and there’s also a spark present, you get water. Hydrogen can then be extracted from the water through the process of electrolysis. 

Oxygen

Oxygen is naturally produced by plants, algae, and other photosynthetic organisms as waste byproducts of photosynthesis. It’s essential for animal life and accounts for 21% of air composition.

Although oxygen can be liberated from water through electrolysis, it’s produced commercially through the industrial purification and separation process from air. The schematic below shows how the process works in more detail.

A diagram highlighting oxygen processing

Dedicated energy crops

Non-food crops, such as bamboo, sweet sorghum, and wheatgrass, are commonly used for fuel. They’re planted on marginal land or in an area that’s unsuitable for food crops. Aside from providing biomass for fuel, they can also help to improve the fertility of the surrounding soil.

Animal wastes

Any livestock farm with cows, pigs, chickens or ducks, for example, produces animal waste. Rich in minerals and nitrogen, this manure is a good source of biogas fuel and organic fertiliser.

A pile of raw cow manure

Algae

Algae is the largest producer of oxygen and grows easily in any body of water, including municipal wastewater. Dead algae makes an ideal and inexpensive source of biomass for fuel conversions.

How is renewable feedstock used in manufacturing?

Renewable feedstock is used as both a raw material and a fuel source in manufacturing. As a raw material, it’s often used to synthesise environmentally-friendly new products like biodegradable plastics.

Renewable feedstock can also play an important role in manufacturing medicines, solvents, enzymes, reagents, and catalysts. Alongside this, renewable feedstocks may be used to power large industrial machines, acting as an alternative energy source to coal, gasoline, and diesel.

What is non-renewable feedstock?

Non-renewable feedstocks are those that are depleted over time and will inevitably be exhausted or become unusable or even impractical to acquire. Non-renewable feedstocks cannot be replenished within our lifetime

 For example, as petroleum reservoirs diminish, it becomes increasingly difficult and expensive to extract.

Crude oil being poured

How renewable feedstocks contribute to sustainability in chemistry

The main goal of green chemistry is to lessen, if not eliminate, the environmental impact and health hazards of chemical products. Using renewable feedstocks achieves both of these aims. 

Sustainable chemistry also focuses on the long-term use of resources, which is made possible by feedstocks that can be easily replenished, whether naturally or through industrial processes.

Original post: Using Renewable Feedstocks in Chemistry. No Republication or Redistribution allowed without written consent. Contact ReAgent Chemical Services for more information.

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