Carbon Capture in the Refining Process (First Grant Scheme)

在炼油厂，二氧化碳来自两个不同的来源--首先是热电联产锅炉中的燃料燃烧(约占总二氧化碳排放量的35%)和过程加热器/加热炉(约占45%)，其次是来自氢气工厂(约占20%)。锅炉/加热器/炉膛中的燃料燃烧被认为是精炼过程中二氧化碳排放的主要来源，约占总二氧化碳排放量的80%。然而，燃料燃烧产生的二氧化碳来源广泛分布在整个综合体中，其烟气中的二氧化碳摩尔分数相对较低(4-15%)。因此，在这些污染源部署和运行碳捕获装置会带来巨大的资本投资和运行成本，同时也会带来操作上的困难。与燃料燃烧排放的二氧化碳不同，氢气工厂的二氧化碳排放具有单一来源的高度集中的二氧化碳(50%-60%)的特征，这意味着从氢气工厂捕获二氧化碳将比从其他来源捕获二氧化碳更有效。这项拟议的研究旨在开发一种真空摆动吸附(VSA)工艺，以在精炼过程中从氢气厂捕获二氧化碳。对于燃烧后捕获，胺工艺迄今为止最接近商业化并准备好部署，但在这种特殊情况下，循环吸附工艺可能比胺工艺更节能，因为进料中的二氧化碳含量很高。此外，应该强调的是，补充现有的H2变压吸附工艺的二氧化碳变压吸附装置具有操作灵活性，因为它可以在各种模式下运行，包括捕获模式、非捕获模式或控制负荷捕获模式。研究将集中于为基于商业吸附剂的二氧化碳变压吸附工艺寻找最佳配置。目标是从氢气变压吸附尾气中回收90+%的二氧化碳，纯度为95+%。将建造一台实验室规模的多柱VSA装置，以证明通过设计良好的循环吸附过程可以实现这一目标。VSA流程的设计和优化将通过在钻井平台运行的同时进行适当的模拟工作来促进。为了优化其蒸汽网络，将实施与VSA工艺集成的示例氢气装置的整体工艺设计。

In the refinery, CO2 comes from two different sources - firstly by fuel combustion in the CHP boiler (around 35% of total CO2 emission), and process heater/furnace (around 45%), and secondly from the H2 plant (around 20%). The fuel combustion in the boiler/heater/furnace is identified as major source of CO2 emission in the refining process accounting for around 80% of total CO2 emission. However, the CO2 sources by fuel combustion are widely distributed throughout the complex and their flue gas has relatively low CO2 mole fraction (4-15%). Therefore, deploying and operating carbon capture units to these sources result in significant capital investment and running cost as well as operational difficulty. Unlike the CO2 emissions by fuel combustion, the CO2 emissions from the H2 plant are characterised by a single source having highly concentrated CO2 (50-60%), which implies that it would be more efficient to capture CO2 from the H2 plant than from the other sources. The proposed research aims to develop a Vacuum Swing Adsorption(VSA) process to capture CO2 from a H2 plant in the refining process. For post-combustion capture, the amine process is, to date, closest to commercialisation and ready to be deployed, but a cyclic adsorption process can be more energy-efficient than the amine process in this particular case due to a high CO2 fraction in the feed. Moreover, it should be emphasised that the CO2 VSA unit supplementary to an existing H2 PSA process has operational flexibility, as it can be operated in various modes, including capture-mode, non-capture mode or controlled-load capture mode.The research will focus on finding an optimal configuration for the CO2 VSA process based on a commercial adsorbent. The target is to achieve 90+% CO2 recovery with 95+% purity from the H2 PSA off-gas. A lab-scale multi-column VSA rig will be constructed to demonstrate that the target can be achieved by a well-designed cyclic adsorption process. The design and optimisation of the VSA process will be facilitated by a proper simulation work in parallel with operation of the rig. An overall process design of an example H2 plant integrated with the VSA process will be implemented for the purpose of optimising its steam network.