Glycerine Distillation & Refining – CMB

1. INTRODUCTION: what is the glycerine distillation & refining process

Glycerine is technically a by-product created during the process of obtaining fatty acids or biodiesel.

To obtain the final product, vegetable oils or animal fats must undergo two steps: glycerine distillation and glycerine refining.

2. INDUSTRIAL APPLICATION OF GLYCERINE

Over time, glycerine has strongly increased its importance and market value, with a production which, in a few years, has gone from 800,000 metric tons per year to over 2 million metric tons per year, also becoming extremely profitable.

Currently glycerine is used both in the pharmaceutical-cosmetic sector and in the food sector. The properties of glycerine are multiple: it helps to preserve foods, sweeten them, humidify them and emulsify them. You can find it practically everywhere: candies, baked goods, flavour, drinks and syrups. Its presence is detected because it is reported on the labels with the code E422.

But not all glycerine is the same, at least from a regulatory point of view.

In fact, even if technically the glycerine obtained from by-product can have the same characteristics and the same purity as that obtained from vegetable oils and animal fats (suitable for pharma grade), only the latter can be used for pharmaceutical and food production.

It is also necessary to say that specifications in the pharmaceutical sector are increasingly rigorous, both in terms of values ​​- increasingly restrictive – and in terms of parameters. The latter mainly concern the stability of glycerine, especially that of colour. These features are specifically requested by end Clients.

3. PRODUCT PROCESSING: distillation & refining phases

In the distillation tower three products are separated; a small stream of glycerine with low boiling impurities (this stream is then reprocessed to recover totally the glycerol), the distilled glycerine and a bottom stream of glycerol with high boiling impurities. This stream too is furtherly processed to recover almost totally the glycerol contained.

The distilled glycerine is then deodorised, cooled and sent to the refining phase. In the past were used carbon in powder form, while now the carbon is used in form of small cylinders. This allows the use of fixed beds reactors without the need of manual cleaning of a filter for separation of the carbon that had to be cleaned every batch.

the bed of activated carbon can then be used for weeks before being replaced.

4. ADVANTAGES OF CMB TECHNOLOGY

Glycerine distillation is a mature technology and plants do not differ substantially from one to another.

However, the CMB solution offers some special features that are worth mentioning, such as:

• a saponification step in our plant, that has the purpose to convert the impurities at low temperature avoiding losses due to polimerisation at high temperatures;
• a proper management of the condensation of the water evaporated, that dramatically reduces the COD of the effluent water.

Being glycerine distillation a vacuum process, which inevitably produces wastewater that needs to go to the effluent treatment, the lower the effluent load, the lower the impact on the environment, with also a positive impact on the overall production costs. The search for lower temperatures is a constant in CMB’s production approach which, in this sense, allows the Customer to obtain a final product with high stability and greater yield.

Those are just some examples of how CMB takes care of the aspects that not all Clients have implemented in their plants and adopts innovative solutions, being a market leader both in terms of quality and with attention to sustainability and reduction of pollution.

A distinctive element of CMB which constantly manages to pursue sustainability objectives through its engineering capacity and the work of its team of technologists, while continuing to offer its Clients constant optimization of resources, constant reliability over time of its solutions and a profit maximization.