Refining is one of the oldest industrial processes in the world. Crude oil has been distilled for centuries by the Persians and other Middle Eastern civilizations to produce tar, used to finish and protect pavements and ship hulls, as well as flammable products for domestic or military uses across the Ancient World.
Of course, refining has changed a lot since ancient times and is constantly evolving to meet market demands, such as low Sulphur fuels, less diesel, etc.
The biggest evolution in refinery processes this past decade has been more and more processes to transform heavy fuels into lighter products by using cracking techniques.
As refining processes become more complex to be competitive in an ever-tougher market, the demand in energy grows in proportion. Nowadays, anything between four and eight tons of hydrocarbons are consumed to process 100 tons of crude, depending on the refinery’s complexity. Integration is maximized as much as possible however there is still room for energy optimization improvement and the industry is well aware of this. For example, as Total states in their sustainability goals: “Optimizing the energy consumption of its operated facilities is Total’s first lever to reduce emissions”.
How can we reduce the carbon footprint?
1. Process optimization
Not all the refineries reach the same degree of complexity, however one common denominator is that they are the masters at process integration, as these processes have been matured literally over centuries. Nowadays, with modern designs and technologies, excess heat is being extensively reused to preheat process fluids and generate steam, hence saving energy and lowering CO2 emissions.
2. CO2 capture
During a conversation with a refinery manager, I was asking what was the main lever on decarbonizing processes in an oil refinery environment, and the answer was CCS (or CCUS as it is also called), meaning Carbon Capture (Utilization) and Storage. Those are complex and CAPEX intensive projects as it involves building basically what is a new plant within the plant, including transportation, storage and finding an end user (reinjection into a field for example).
3. Low temperature waste heat recovery
Although very well integrated in terms of waste heat recovery, lower temperature waste heat (below 120 degrees Celsius) has not yet been utilized in the processes. The main reason is that it has been historically difficult to harness low grade waste heat and efficiently produce electricity out of it. Nowadays, with new technologies emerging on the market, it is finally possible to capture this heat and use it to create value and sustainable, baseload electricity. Climeon’s heat power system is one of such technology innovations, and effectively the one with the highest conversion efficiency on the market.
Where does the waste heat come from?
Refining operations are conducted at elevated temperatures. A refinery must be in heat balance, meaning all heat added in the form of fuel burned, steam consumed, or coke burned must be removed by one of the various cooling systems. Water cooling is one such system. The others are air cooling and heat exchange with other streams. Process water is also a source of heat, such as steam condensate or water coming out of the sour water strippers.
As far low temperature waste heat recovery is concerned, the three main sources are:
- Flue gases, which can be cooled using heat exchangers. The temperature of these flue gases cannot be lowered to the point where Sulphur dioxide would start precipitating and corroding the equipment, giving only “low temperature” waste heat to harvest.
- Water cooling, which is looped through cooling towers, with all heat dissipated into atmosphere.
- Air cooling, with heat also dissipated into the atmosphere.
Using and/or by-passing these systems using Climeon’s heatpower modules to cool down the fluids and produce clean, renewable electricity is an ideal first step towards efficient waste heat recovery.
Whether the water comes from the water cooling system, the vacuum distillation column or the hydrotreating process or the sour water strippers, the ideal situation is to harness their heat at the source. These processes and others take place in different locations within the refinery which is in general set in enormous premises, some refineries are indeed the size of a small town.
How do you handle waste heat recovery in a large premise?
Well, the answer is simple and not so simple at the same time.
Simple, because the solution is small, baseload and distributed powerplants. Install a flexible solution at the source of the waste heat that is perfectly adapted to the thermal energy available at that spot only. Replicate that throughout the refinery where cooling availability and electrical connectivity allow for.
Not that simple, because in order to do this, one needs a very efficient and compact system at a low range of temperatures otherwise the economics would not work.
So, what is the solution?
Climeon heatpower system is designed exactly for this purpose. Its compact size was engineered to fit into tight spaces in engine rooms on board of ships and it is the most efficient system at these temperatures on the market, at more than 50% over traditional efficiencies due to its patented design.
Its modularity allows a flexible deployment and an unrivalled adaptability to configuration changes.
This is how the big refineries are solving their energy efficiency issues. Sustainable solutions like that of Climeon can help refineries lower their carbon footprint and thus contribute to the sustainability goals highlighted by their companies.
These past few months have seen oil majors committing to ambitious targets on net-zero for the years to come, waste heat recovery and Climeon system will help achieve these goals.