The petrochemical industry is booming! The main reason for its success? Its versatile product range from petrol to plastics. Since market demand is increasing, the industry has a lot to gain from efficiency and uptime. One of the many tasks crucial to maximizing the return of your petrochemical installations is ‘decoking’. But what exactly is decoking?
Let us make a brief comparison. During the cracking process in petrochemical installations carbon deposits are formed on the walls of the cracking furnace. Similar to ice formation in your fridge at home, this layer of carbon will slow down the heat transfer and thus increase your energy consumption … and energy bill. The thicker the layer, the more energy is consumed. In order to keep this under control, the cracker at the heart of the petrochemical installation needs to be decoked on a regular basis. Just like your fridge needs to be defrosted. But unlike with your refrigerator at home, getting rid of those deposits is not that easy and requires a special intervention.
Let’s take a closer look at how such an intervention works and what you can do to carry out this process as efficiently and smoothly as possible.
How and why do these deposits ‘stick’ to the walls?
Steam cracking is a widely used petrochemical process in which a long chain of hydrocarbons are broken down into shorter ones (simpler molecules) by heating them up. High temperatures and high pressure are thus required. The result of this industrial process is the production of ethylene, best known from polyethylene.
Let’s go into a bit more detail. Each time a hydrocarbon is cracked at a high temperature, a carbon molecule (coke) is released. These cokes tend to form a layer on the walls of the petrochemical installation. But this layer of coke makes it harder for the installation to efficiently transfer heat. As a result, the cracking furnace consumes a lot more energy. And in the long term, the petrochemical process will no longer be controllable and will lead to technical issues or even breakdowns.
To make your petrochemical installation run smoothly again, you have to remove these waste carbons – just like you have to defrost your refrigerator once in a while. This process of removing coke is called ‘decoking’. But how does this process of decoking work?
The usual way of getting rid of these coke deposits is to inject compressed air. Thanks to the compressed air & heat, the hard layer of carbon is burned off, converted to CO2 and vented from the installation. Ideally the decoking process is performed on a regular base to prevent the installation from breaking down completely. BASF, a world leader in chemicals, sets a good example. The company turned to Atlas Copco Rental to carry out a decoking process once every 7 years. Read more about this partnership here.
So what to do? DIY or choose an external supplier?
This decision depends on whether your petrochemical plant is fit to execute a decoking process. How do you know this?
Does your plant have the capacity to provide plant air?
If this is not the case, an external supplier can provide rental air.
If you do have the capacity to provide air plant, then ask yourself the following questions:
- Do you have sufficient spare capacity?
To bring decoking to a successful conclusion, you need a lot of compressed air. External suppliers generally have a large fleet of compressors and therefore also a larger capacity to provide spare compressed air. This ensures that other processes on your plant will not be interrupted.
- Do you have the right compressed air for this specific application?
Decoking requires 100% oil-free air. Only class zero oil-free air compressors guarantee that your installation will not be contaminated with e.g. oils. This reduces the risk of having these oils interfere the normal operation of the petrochemical plant later on.
In addition, the temperature of the compressed air plays an important role. An external supplier can deliver air at a temperature appropriate to perform the decoking process as efficiently as possible, and can work out the most efficient set-up (e.g. use dry air/ not).
- Do you have enough machines to carry out the decoking process as fast as possible?
Remember that every minute (part of) your plant is shut down and your installation is not working, you lose a significant amount of revenue.
As said before, an external supplier is usually in the possession of a large fleet of air compressors. This ensures you that a sufficient amount of compressors will be available at the time of maintenance or breakdown, reducing downtime to a minimum.
- Do have the right equipment and accessories to connect it to the cracking furnace?
Suppliers usually have the right equipment for this type of job. They can also supply hoses/pipelines, dryers and manifolds to connect different air compressors to your petrochemical installation.
Besides that, an external supplier can identify the optimal place for injecting compressed air and can install the necessary equipment close to that point.
- Do you have staff members you can assign to this project?
When you choose to do the decoking yourself, don’t forget you will also have to allocate teams while ensuring the rest of your plant remains operational, etc. In other words, you have to design a work process for decoking from start to finish.
Suppliers on the other hand are used to performing such processes and are equipped with the right tools allowing them to work more efficiently. And although you have to pay your supplier, you will end up saving time and money!
Don’t wait, hiring an external supplier like Atlas Copco Rental can save you time and money
In the event that your petrochemical installation breaks down, Atlas Copco technicians are available 24/7. Depending on where your plant is situated, our technicians can be on site within the hour (!) after the breakdown of the installation.
Atlas Copco can also be the perfect partner for scheduled maintenance of your petrochemical installation. We offer customized solutions to meet all your needs.
As a supplier, our ultimate goal is bringing uptime. We want to make sure that no time – and money – is lost.
- Oil-free compressed air revitalizing petrochemical installations - September 6, 2018