The refining industry explores new paths to save energy and reduce carbon emissions
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Recently, the **Energy Bureau released a compilation of advanced energy-saving and carbon-reduction technologies as well as typical cases in the refining industry, summarizing the advanced technologies and effective practices for energy saving and carbon reduction in this sector over the past few years. While reviewing these cases, the reporter found that the refining industry is taking various measures to reduce energy consumption and carbon emissions – ranging from energy savings at individual units to those across the entire plant, as well as from the recovery of waste heat to turning waste into valuable resources. There are increasingly more typical practices that can serve as references. Industrial waste heat has a wide range of application scenarios. It is known that petrochemical enterprises possess substantial amounts of low-temperature waste heat, with temperatures mostly falling within the 50–150°C range. Making effective use of this waste heat is of great significance for achieving energy conservation and emission reduction goals, as well as for reducing costs and increasing efficiency. Sinopec Yanshan transforms this waste heat into a valuable resource, using efficient heat transfer and recovery mechanisms to convert the excess heat from the facilities into thermal energy that can be used for clean heating in residential areas. The company employs a comprehensive resource utilization approach that involves the direct use of moderate-temperature heat sources in its production facilities, as well as the indirect utilization of low-grade heat sources. It recovers the waste heat generated by units such as those used for benzene production within the plant, as well as some of the waste heat from circulating water. By using efficient and clean heating technologies such as \"heat exchangers + heat pumps,\" it supplies heating energy at 70/50°C to Beiran Group’s Fangshan Heating Company; the annual amount of waste heat that can be utilized is approximately 530,000 GJ. The process hot water waste heat recovery project for China National Offshore Oil Corporation’s 300,000-ton ethylbenzene plant utilizes class II absorption heat pump technology to convert the low-quality process hot water from this plant into high-quality steam at 0.35 MPa. This approach also addresses the issues of inefficient utilization of the 1.0 MPa steam in the styrene plant, as well as the excess amount of low-temperature hot water available throughout the plant. The company uses direct thermal drive, leveraging low-grade heat sources to pump heat from a lower-temperature source to a higher-temperature one. The low-temperature heat comprehensive utilization renovation project at Liaoyang Petrochemical Company makes use of the circulating hot water generated by the existing low-temperature waste heat systems in the aromatics and refining departments, while keeping the original process unchanged. This water is used to power low-temperature heat generation equipment and lithium bromide refrigeration units, thereby supplying electricity to higher-level substations and providing cooling for the factory buildings.
Breakthroughs have been achieved in energy-saving technologies for key energy-consuming equipment. It is known that refining heaters are critical energy-consuming devices in petrochemical enterprises, accounting for approximately 50% to 80% of the total energy consumption of such facilities. Energy savings in these heaters play a crucial role in reducing the energy consumption of refining and petrochemical companies, thereby helping them improve efficiency and achieve sustainable development in a green and low-carbon manner. The comprehensive green, energy-saving, and carbon-reduction technology for refinery heating furnaces developed by Sinopec Engineering Construction Co., Ltd. increases the thermal efficiency of such furnaces to over 95%, while significantly reducing emissions of CO₂ and NOx. This technology focuses on conducting integrated research on various techniques such as efficient air preheating, fuel preheating, efficient combustion, composite refractory materials, new type of baffle valves, leak sealing, intelligent control, waste liquid recycling, and advanced flue gas recovery. It involves the development of energy-saving equipment and components such as highly efficient and durable air preheaters, new types of sealing structures for furnace bodies, new burners, and viewing ports, thereby enabling precise control over the oxygen content in the furnace chamber and reducing losses due to flue gas emissions, air leakage into the furnace chamber, incomplete combustion, and heat loss from the outer walls. To address the issues of incomplete and unstable combustion with conventional low-nitrogen burners in the low-temperature furnace chambers of heating furnaces, as well as the high levels of CO and O₂ in the exhaust gases, Sinopec has also explored the development of low-CO combustion technology for such furnace chambers. This technology employs the use of a central gas gun, staged combustion of fuel gas, and premixed combustion of the primary fuel gas, thereby effectively addressing the issue of high levels of both CO and O2 during low-temperature furnace combustion. It enables the CO content in the exhaust gases to be reduced to below 50 mg/m³, while keeping the NOx content within 60 mg/m³. In addition, companies such as China National Petroleum Yunnan Petrochemical, North China Huajin of the Ordnance Industry Group, and CNOOC Huizhou Petrochemical have also carried out valuable explorations into energy-saving optimization of their facilities.
A new paradigm for energy conservation across the entire industry has emerged. With the rapid development of electricity and natural gas as alternative energy sources for transportation, it has become imperative for energy-intensive companies that rely primarily on oil refining to break away from traditional development models and accelerate the adjustment of their product portfolios as well as pursue a green and low-carbon transformation. Among the cases presented this time, there are enterprises that focus on energy conservation across their entire operations and improving energy efficiency in order to enhance their overall competitiveness. By applying systematic thinking to energy conservation management and adopting a \"gradual catch-up\" approach to energy management, Sinopec Qingdao Refining & Chemical has systematically implemented 33 projects aimed at improving energy efficiency. These projects include the energy-saving renovation of the outer walls of green heating furnaces in facilities for hydrogen production and styrene production, as well as modifications to heat exchangers used for reformation feedstocks and products. As a result, the refinery’s energy efficiency has ranked first in China’s crude oil processing industry for 12 consecutive years. It is worth noting that the company makes full use of advanced information technology to carry out joint energy-saving optimizations for individual units as well as between different units. It organizes and trains technical personnel in the use of process simulation software, and conducts regular optimization analyses of the entire production process. On this basis, optimization of a single unit, joint optimization of multiple units, optimization of direct material and heat supply between units, as well as global optimization of the steam system were achieved. Yunnan Petrochemical, part of China National Petroleum Corporation, takes into account the actual conditions of production, focuses on optimization throughout the entire process, and carries out comprehensive improvements to the refining processes as well as to the use of fuels and power. Energy-saving and consumption-reduction measures are implemented in every stage and at each step of the production process. The company analyzed each system such as those for water, electricity, steam, gas, air, nitrogen, and hydrogen in detail, coordinated them precisely, and optimized energy savings across the systems. Improve hydrogen production efficiency and optimize hydrogen usage, ensure proper steam balance, and reduce steam consumption for processes ； Optimize the ratio of heat supply from upstream and downstream sources; under normal operating conditions, light oil units should be supplied with heat 100% directly, while heavy oil units should have a heat supply ratio of no less than 80% ； Fully implement direct oil delivery to reduce power consumption and VOCS emissions ； Priority will be given to integrating the PSA4 desorbed gas into the pressure reduction skid, supplying the secondary naphtha from the normal pressure line directly to the naphtha hydrogenation unit, feeding the crude naphtha from the naphtha hydrogenation unit directly to the double dehydration unit, and supplying the naphtha from the third normal pressure line directly to the reforming unit.
The refining industry explores new paths to save energy and reduce carbon emissions
The oil refining industry still has a long way to go in exploring new ways to save energy and reduce carbon emissions
In an industry of this size, any progress is significant