Sep-2024

Oil refinery roadmap for decarbonisation of emissions (RI 2024)

Achieving net-zero greenhouse gas (GHG) emissions is a critical goal for many industries worldwide, including the refining sector

Arjun Balakrishnan
Worley

Article Summary

Achieving net-zero greenhouse gas (GHG) emissions is a critical goal for many industries worldwide, including the refining sector. The Refinery Decarbonisation Study aims to achieve this objective by 2050, addressing Scope 1 and 2 emissions and some aspects of Scope 3. This case study provides a comprehensive analysis of the two-phase approach taken to develop this roadmap, highlighting the methodologies, key projects, timelines, and expected benefits.

Background
Refineries are significant contributors to global GHG emissions due to their energy-intensive processes. Reducing emissions from such facilities involves complex challenges, including the need for advanced technologies, substantial investments, and strategic planning.

The Refinery Decarbonisation Study was initiated to create a clear and actionable pathway to net-zero emissions from a Scope 1 and 2 perspective. It focuses on both direct emissions (Scope 1) and indirect emissions from purchased electricity and heat (Scope 2).

Study Phases and Methodology
The study was conducted in two distinct phases:

Phase 1: Screening of decarbonisation options
Objective: Identify and evaluate a broad range of potential options for reducing and offsetting GHG emissions at the refinery.

Methodology:
• Identification of options: A total of 42 options were identified, including direct abatement measures, carbon capture and storage technologies, switching to low-carbon fuels, CO₂ valorisation, and GHG offsets.
• Evaluation criteria: Each option was assessed based on several criteria, including technical feasibility, potential for future advancements, economic viability, and overall impact on emissions reduction.
• Scoring and selection: Options were scored based on weighted criteria to reach a final ranking. The top 20 options were selected for further detailed evaluation in Phase 2.
Options evaluated in Phase 1:
1. Direct abatement measures
2. Implementing carbon capture and storage technologies
3. Switching to low-carbon fuel
4. CO₂ valorisation
5. GHG offsets

Phase 2: Detailed evaluation of selected options
Objective: Conduct an in-depth assessment of the 20 selected options from Phase 1 to develop a detailed roadmap for achieving net-zero emissions.

Methodology:
* Technical considerations: Evaluations included the maturity of existing technologies, potential for future advancements, and feasibility of implementation.
* Economic considerations: Detailed calculations of costs and benefits for each option, including Capex and Opex analyses.
* Net-zero implications.

Description of Key Projects
The detailed evaluation phase led to the identification of key projects crucial for the refinery’s journey to net-zero emissions with respect to Scope 1 and 2. These projects are categorised into different areas, such as carbon capture, direct abatement, fuel switch, and CO₂ transport and storage. The most significant projects are:
1. Carbon capture
• Convert grey hydrogen to blue hydrogen: Implementing carbon capture technology to convert existing grey hydrogen production to blue hydrogen, significantly reducing CO₂ emissions.
• Power plant carbon capture: Capturing CO₂ from cogeneration units, which provide both electricity and heat to the refinery.
• Boiler carbon capture: Installing carbon capture systems on boilers to reduce emissions from combustion processes.

2. Direct abatement projects
• Hydrogen management study: Using hydrogen pinch and recovery technology like PSA and membrane to recover hydrogen from the fuel gas system and reducing the usage of hydrogen in the major hydroprocessing and cracking units. This reduces the need for additional hydrogen production and associated emissions.
• Operational optimisation of site utility system: Enhancing the efficiency of the site’s steam and power system to reduce overall energy consumption and emissions.

3. Fuel switch projects
• Biomass as fuel in boilers: Replacing natural gas conventional boilers with biomass boilers to utilise renewable energy sources.
• Switch heaters to low-carbon hydrogen: Transitioning heaters from refinery/fuel gas/fuel oil/natural gas to low-carbon hydrogen to reduce emissions.

4. Import green hydrogen
Substituting natural gas with imported green hydrogen was also considered, reducing the refinery’s carbon footprint.

5. CO₂ valorisation pathways
Two CO₂ utilisation options were considered during Phase 2:
• Methanol from CO₂
• Synthetic aviation fuel (SAF) from CO₂.
These options were found to be economically unattractive at present due to future price trends of products and raw materials. However, it is recommended to perform market studies at appropriate times as specified in the roadmap timeline.

6. CO₂ transport and storage
• Store captured CO₂ via pipeline: Developing infrastructure to transport and store captured CO₂, ensuring its sequestration.

7. GHG offset projects
• Nature-based solutions: Implementing nature-based solutions, such as reforestation, to offset GHG emissions and enhance biodiversity.
• Direct air capture: Installing a direct air capture plant to offset the remaining GHG emissions required to reach net zero.
• Buying high-quality credits.

Decarbonisation Roadmap and Timelines
Recommended roadmap
The recommended roadmap is designed to be technically feasible and economically viable (Figure 1). It incorporates a mix of different options to reduce the risk of sunk capital. It aims to achieve a 35% CO₂ reduction by 2030 and net-zero emissions by 2050.

Key roadmap routes
Route 1: Maximum CO₂ capture case Advantages: Lower abatement costs.
Challenges: High CO₂ sequestration or utilisation volume.

Route 2: Least CO₂ capture case Advantages: Reduced CO₂ sequestration or utilisation requirement, reduced plot area.
Challenges: Higher operating costs and higher abatement costs due to green hydrogen prices.

Net-zero roadmap
The roadmap follows a ‘waterfall’ approach, where a sequence of projects builds progressively towards the ultimate goal of net-zero emissions. This approach ensures that each project is implemented based on the progress and outcomes of previous projects, minimising risks and optimising resource allocation. A skeleton of the timeline is shown in Figure 2.

Marginal abatement cost curves (MACC)
Worley Consulting delivered an MACC of options that plots the abatement potential and cost (Figure 3). This will help the refinery stakeholders prioritise decarbonisation options based on impact and costs.

Conclusion
The Refinery Decarbonisation Roadmap Study provides a clear and comprehensive pathway for achieving net-zero emissions at the Scope 1 and 2 levels by 2050. The study emphasises the importance of a mix of technical and economic considerations and the need to continuously update and revisit the roadmap at key stages to reduce the risk of sunk capital.

Implementation of this plan will bring significant environmental and socio-economic benefits. The Net Zero Road Map is a dynamic document that will guide the refinery’s transition to a net-zero future.

This short article originally appeared in the 2024 Refining India Newspaper, which you can VIEW HERE