Sep-2023

Breaking boundaries to decarbonise plant emissions

How refineries are thinking outside the box to curb emissions and build a clear but flexible path through the energy transition.

Duncan Mitchell
KBC (A Yokogawa Company)

Article Summary

The petroleum refining industry is under immense pressure to reduce emissions. Collectively, they play a major role in producing atmospheric greenhouse gasses (GHG). Based on KBC’s internal model, a facility processing 150 thousand barrels of crude oil per day emits more than 2 million tonnes of Scopes 1 and 2 carbon dioxide (CO₂) from its processes, heaters, and boilers every year.

Further, the E10 gasoline, which contains 10% renewable ethanol and is produced from the facility’s gasoline blendstocks, releases more than four times the amount of CO₂ in use compared to the emissions generated during its production, blending, and distribution process. This example highlights the need to consider the product’s entire lifecycle when assessing its carbon footprint.

Researchers show that refineries worldwide emitted about 34.1 gigatons (Gt) of GHGs, with a 0.7% annual increase between 2000 and 2021 (Ma, et al., 2023). According to the International Energy Agency, oil and gas operations contribute about 5.1 Gt of carbon dioxide-equivalent (CO₂-eq) each year in total indirect GHG emissions (IEA, 2023). This accounts for 15% of the total GHG emissions in the energy sector.

The impact of human-produced climate change is undeniable. Global oil refineries and petrochemical plants are increasingly addressing their role in this crisis. Their aggressive goals are aimed at reducing their emissions and those of their products. A comprehensive and practical way to achieve these goals and reach net zero is to build a viable roadmap, such as the example in Figure 1.

As Figure 1 shows, a one-size-fits-all solution does not exist. Furthermore, finding a solution, or the most effective combination of solutions can be daunting. It demands a substantial investment of capital, time, and co-ordinated efforts to ensure the solution is profitable and sustainable. Most agree that the answers can be found both inside and outside the facility’s boundaries. However, the latter option offers the best chance of significant reductions.

To address this rising concern, governments and regulatory bodies worldwide are responding by applying increased pressure for change. They are implementing carbon taxes and offering incentives for low-carbon product credits, among other approaches. These strategies encourage traditional refiners, who prioritise profits in competitive markets, to invest in new technologies, feedstocks, and products.

This article delves into innovative techniques and technologies that go beyond the norm to decarbonise process plant emissions. In other words, operators will need to consider investing in solutions that lie beyond their usual boundaries; they must think outside the box.

Standard emission reductions
Since 1979, KBC has been a reliable partner for clients in the refining and petrochemical industries. The emphasis has been to help its clients improve yields and profits while cutting energy costs. As ever, these industries face constant market pressures due to fierce international competition and the demands for higher returns on capital.

Historically, energy efficiency has proven to be a relatively low-risk, low-capital way to boost margins. As a fortunate side-effect, this approach also lowers energy use per unit of production to reduce GHG emissions. KBC has assisted hundreds of global facilities to decrease their energy consumption. KBC estimates the results from those projects have removed more than 400 million tonnes of CO₂ emissions. To put this into perspective, it is equal to the annual CO₂ emissions of Australia.

Energy management strategies
Most energy efficiency opportunities fall into a few major categories, including:
υ    Furnace efficiency
ϖ Heat integration (pinch analysis)
ω Process optimisation
ξ Power generation system optimisation, as illustrated in Figure 2.

Energy efficiency
Continuous improvements in energy efficiency often yield diminishing returns as larger benchmarking gaps close. Based on KBC’s global energy benchmarks, even the most wasteful energy users would only achieve a 20-30% reduction in their Scope 1 and 2 emissions if they became top-quartile facilities. This course of action remains the quickest and often least expensive way to start the journey toward eliminating all GHG emissions. As the past few decades have shown, cutting costs and improving margins are sound business objectives. Thus, digging into a detailed review of energy with a ‘how low can you go’ attitude is always the recommended first step. It is a classic no-regrets move.

However, many refiners are setting targets beyond 30% reductions in their own Scope 1 and 2 emissions by 2030. Achieving these goals requires thinking beyond standard energy efficiency improvements and embracing innovative solutions.

Integrating novel energy efficiency solutions
Energy efficiency is an effective first step along the roadmap to eliminate Scopes 1 and 2 emissions. Refineries and petrochemical systems consume large amounts of energy for chemical reactions, resulting in substantial emissions. Put simply, energy is fundamental to producing fuels and petrochemicals. Once energy consumption is minimised through the energy efficiency benchmarking described above, the remaining challenge is to eliminate GHGs from the facility. This can be achieved by either providing emission-free energy sources such as zero-carbon intensity hydrogen and electricity or capturing the resulting emissions before they are released into the air via carbon capture.

Misleading internal approaches
Here is the catch. By purchasing more electricity from the grid to energise modified fired heaters, the increase in Scope 2 emissions outweighs the decrease in Scope 1 emissions, as shown in Figure 3. This scenario leads to higher product carbon intensities. Using hydrogen-fired heaters and boilers also raises CO₂ emissions due to the fossil energy required to operate the steam methane reformer (SMR) combined with the CO₂ emissions produced by the reaction. If natural gas is purchased and the SMR is used to produce the necessary hydrogen, CO₂ emissions will increase. Even with systems such as amine absorption in place, only half of the expected CO₂ may be captured. This is due to the extra boiler load required for amine regeneration steam and the electricity needed for compressing the captured CO₂.