# Using Machine Learning Language Models to Generate Innovation Knowledge Graphs for Patent Mining
## 4 Case Study: Graph Summaries of Carbon Capture Patents  
This study uses Carbon Capture and Storage (CCS) as our technical domain for the case study. CCS is an important research and development field and there are more than 120 countries committed to be the regions with virtually zero carbon dioxide (greenhouse gas) emissions by 2050 [54]. CCS is one of the most promising strategies for reducing greenhouse gas emissions in the environment. It enables the continued use of fossil fuels while controlling CO\({}_{2}\) emissions, without compromising the security of the electricity supply. Carbon capture technology starts by capturing the carbon dioxide from the electricity generated by the power plant. There are three main techniques for capturing carbon from fossil fuel power plants, namely post-combustion, pre-combustion fuel decarbonization, and the combustion of fuel in pure oxygen. The post-combustion and pre-combustion processes include carbon capture by the absorption and adsorption of the CO\({}_{2}\), and carbon dioxide capture by separation, using permeable membranes for the CO\({}_{2}\), and gasification and combustion of the fuel syngas/hydrogen. After capturing the CO\({}_{2}\), the gas is compressed, transported, and injected. The pressurized supercritical carbon dioxide is transported from the capture point through a network of pipelines. Carbon dioxide can be recovered in two ways. The first step is to reuse the recovered carbon dioxide, for example, by adding it to a solution to adjust the pH value of the solution. The second step is by geological storage. There are three main types of underground storage sites: deep brine, depleted oil/gas reservoirs, and deep unrecoverable coal seams [55]. Based on the carbon capture literature,  
Figure 4: Adding edge interactions between nodes. Figure 3: Schematic diagram of co-occurrence matrix construction. the overall knowledge ontology schema of CCS technologies and key terms are shown in Figure 5.  
There are several promising new materials for capturing CO2 from the post-combustion, pre-combustion, and oxyfuel combustion processes. In recent years, there are many studies that tend to address the energy-intensive regeneration steps and chemical degradation of solvents as absorbents in flue gas separation. Current trends in the development of carbon capture/absorbent materials include physical/chemical absorbents, membranes, adsorption on solids using pressure or temperature variations, distillation, natural gas hydrate formation, chemical cycle combustion using metal oxides, etc. [56]. The synthesis procedure of the material overview can be quickly presented graphically with appropriate web visualization tools to assist the user in reading and correcting. The nodes in the procedure graph are represented by three colors representing the material, operation, and unit. The entire flowchart will be presented as a directional graph, with arrows pointing to the next step or interconnected nodes, according to the sequence of steps. To present the step-sequence more clearly, the linked lines and arrows are presented in shades of color, with lighter colors indicating earlier steps and darker spectrum frequencies indicating later steps. This flowchart provides another easy way to present chemical flowcharts. Compared with the P&ID diagram (Piping and Instrumentation Diagram), which requires a relevant background and long training to be familiar with the way of reading P&ID diagrams, this flowchart can be faster and easier for people without the background knowledge to understand the process. The summary graph allows the researchers to quickly understand the content of the patent. The nodes on the graph show the keywords in the text, and the more important keywords appear in larger nodes. The relationship between the nodes is shown by the thickness of the connecting lines, with the larger the association, the thicker the line. With the appropriate graph layout, the clustering of the nodes in a graph can be observed, which helps researchers to grasp the text content.