Introduction
What is spent earth oil recovery? What even is spent earth? Both good questions to start this blog post with.
In the vegetable oil industry, refining processes are used to purify crude oil extracted from plant-based oil-bearing materials. The chemical refining process involves degumming, alkali refining or neutralisation, bleaching, dewaxing, and deodorisation. Meanwhile, physical refining includes the processes of degumming, pretreatment and bleaching, dewaxing, optionally post-bleaching, and deodorisation and deacidification. Pretreatment, bleaching, and post-bleaching all involve the use of bleaching earth.
What use is bleaching earth? Well, it has the ability to adsorb phosphatides/residual gums which ensure the lightening of colour.
And spent bleaching earth? That’s what we call the bleaching earth once it has been “spent” or used in the refining of edible oil. Spent bleaching earth is the solid waste generated during the refining process. It isn’t, however, composed entirely of bleaching earth and the impurities it has extracted – it also absorbs about 20% to 40%, by weight, of the vegetable oil it is meant to refine.
Now, leaving this oil in the bleaching earth isn’t a good idea. It has several risks – environmental, safety, and financial – which we will discuss in more detail later. That’s precisely why the spent earth oil recovery process is so important.
In this blog post and the next, we’ll be talking about all things related to spent bleaching earth oil extraction. From the imperative to set up more spent earth oil recovery plants to the spent earth oil recovery process, it’s the perfect guide to mastering the spent earth oil recovery process and maximising the efficiency and profitability of your plant.
If investing in a spent earth oil recovery plant is on your agenda, you’re in the right place. Let’s dive right in.
What is spent bleaching earth oil extraction?
Spent earth oil recovery is the value-added process used in the vegetable oil industry to extract residual oil from used or spent bleaching earth. If carried out efficiently, the spent bleaching earth oil recovery process can result in the recovery of very high quantities of oil, leaving behind less than 1% in the spent bleaching earth.
To give you a quick overview, the spent bleaching earth oil recovery process begins with preparing the spent earth and extracting the oil in it using a solvent like hexane. The solvent is recovered for reuse through the process of distillation, while the extracted oil is sold for industrial use in, say, the oleochemicals, biodiesel, or lubricant industries.
The imperative to set up more spent earth oil recovery plants
If you’ve been planning a new investment in the vegetable oil industry, we can’t stress enough the need for more spent earth oil recovery plants. There are several reasons for this.
These reasons range from the financial, environmental, and safety perspectives to a more strategic perspective for your business.
Value creation. For starters, you have to consider the amount of value you’re creating by investing in a process as critical as spent bleaching earth oil extraction. This is because the oil you recover can be resold for industrial applications, like we mentioned above. Oil recovered from spent bleaching earth isn’t usually suitable for food applications, but it can most certainly be put to good use in the biodiesel, oleochemicals, soap, and lubricant industries.
Some estimates assume an average oil retention volume of 20% of the bleaching earth used. That works out to many hundreds of thousands of metric tonnes of oil lost year on year. This is a massive economic loss, one that we feel compelled to prevent. If you’re already involved in edible oil extraction or refining, this is also a great way for you to increase revenue generation and improve the profitability of your operations.
Not all spent bleaching earth oil extraction operations can achieve this, but when carried out in a closed circuit, the spent bleaching earth oil recovery process can also produce oil suitable for edible purposes.
We’ve talked a lot about the oil that you can recover from the spent bleaching earth oil recovery process. But let us not forget the spent bleaching earth itself. After all that residual oil is extracted from it, the bleaching earth is suitable for use as fuel in boilers – it’s important to note that this would, in fact, require a slight adjustment to the oil extraction process. The de-oiled spent bleaching earth also has applications in cement manufacturing, silicate fertiliser manufacturing, and as a soil conditioner.
Environmental compliance. Spent bleaching earth, as it is after the bleaching process, is not suitable for use in any industry. In fact, it is not even suitable for disposal in landfills. It can pollute groundwater systems as well as the soil when the oil in it leaches out during rain. Recovering the oil minimises the amount of hazardous waste that needs disposal. Bringing the residual oil content in spent bleaching earth to less than 1% by weight helps it meet environmental regulations for its disposal. So, as you can see, even if you didn’t have any intention of value addition or additional revenue generation, the spent earth oil recovery process is quite indispensable to any business that values health, safety, and compliance.
Safety concerns. One of the most fundamental reasons for spent bleaching earth oil extraction is safety. Having residual oil in it can make spent bleaching earth prone to spontaneous combustion – that’s not a risk anyone would want to take. Whether it’s during stocking or disposal, you want to ensure the health and safety of your personnel and the communities around. The spent earth oil recovery process reduces this risk by a significant amount.
ESG concerns. All the above reasons make having a spent earth oil recovery plant non-negotiable if you’re in the edible oil refining business. But if we’re being honest, spent bleaching earth oil extraction is more than just a practical concern; it’s a strategic one.
As the world moves full force ahead into a future that is plagued by climate change, diminishing resources, and heavy pollution, ensuring your business is future-ready should be top of your mind. This involves not only finding additional sources of revenue but also adopting principles of sustainability, circular economy, and efficient resource use.
Maximising the efficiency of your spent earth oil recovery process is one way to signal that you’re aware of what the future brings and that your business is ready to face it boldly. Not placing profits over people or the planet, but working to help your business, the environment and communities thrive simultaneously.
As such, investing in a spent earth oil recovery plant is as much an operational decision as it is a strategic one.
In part two of this blog post, we’ll dive into the specifics of the spent earth oil recovery process and the choices you can make to improve the efficiency and profitability of your plant. We promise it’ll be worth your time… stay tuned.
