Total investment of 179.42 million! Maoming Petrochemical’s coal-based hydrogen production plant: project for improving raw material efficiency and optimizing the utilization of oil residues!

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According to the official website of the Maoming Shengtai Environmental Protection Bureau, the environmental impact assessment report for the \"Technical Transformation Project for Improving the Efficiency of Raw Materials and Making Use of Oil Residues in Sinopec Maoming Branch’s Coal-to-Hydrogen Facility\" has been accepted and an announcement regarding this has been made. The total investment in this project is 179.42 million yuan, and it is funded and constructed by Maoming Petrochemical. The project is located in the Hexi Industrial Zone of Maoming City (within the refinery). More details on the project are as follows: 1. Project construction overview: On November 5, 2018, the Maoming Branch of Sinopec Corporation (hereinafter referred to as “Maoming Branch”) received approval from the former Maoming Environmental Protection Bureau for its 2.6-million-ton-per-year slurry-bed residue hydrogenation unit, in the form of the document titled “Approval on the Environmental Impact Report for the Product Structure Optimization Project of Maoming Branch of Sinopec Corporation” (Maohuan Shen No. 28). The construction scope of this project includes the main facility, which is the 2.6-million-ton-per-year slurry-bed residue hydrogenation unit ； The oil residue (slag) produced as a by-product of the project is sent to the plant’s coking unit as raw material. On December 31, 2020, the 2.6 million tons per year slurry-bed residue hydroprocessing unit at the Maoming branch was put into operation successfully. This unit enables the efficient conversion of heavy and low-quality crude oils into cleaner petroleum products, thereby optimizing the product structure. The by-product generated by this unit is 18.59 tons per hour (446 tons per day) of oil residue; this residue is currently sent to the plant’s coking unit as raw material for the production of petroleum coke. However, the presence of this oil residue in the coking unit results in higher levels of residual carbon, which makes it difficult for the coke to meet the quality standards specified in the standard “Petroleum Coke (Raw Coke)” (NB/SH/T0527-2019) with regard to ash content and metal levels (vanadium, iron, nickel); as a result, some of the coke samples are considered unqualified. The Maoming branch plans to change the current method of producing petroleum coke from oil residue through coking to a method of producing syngas from oil residue through gasification. It intends to utilize the existing coal-to-hydrogen production facility at the Maoming branch to carry out the \"Project for Improving the Efficiency of Raw Materials Used in Coal-to-Hydrogen Production and Utilizing Oil Residue (hereinafter referred to as ‘this project’)\”. In this project, oil residue will be used as a raw material in the coal-to-hydrogen production facility; the SE water-coal (coke) slurry gasification technology will be employed to produce syngas (CO+H2), while the ash and residues will be processed for resource utilization, thereby achieving coupled gasification of coal and oil residue. The SE water-coal (coke) slurry gasification technology demonstration unit, developed through collaboration between Sinopec and East China University of Science and Technology, was put into operation at Zhenhai Refining & Chemical Company in January 2019, boasting performance levels and technical specifications that are among the best in the world. The core equipment of this technology – the dual-slurry-channel burner – features two separate slurry channels, internal and external, allowing it to process two different types of materials simultaneously. It also has a long service life, providing reliable technical support for the coupled treatment of oil residues using gasification units. On March 18, 2021, the technical renovation project aimed at improving the efficiency of raw material utilization and making better use of oil residues in Sinopec Maoming Branch’s coal-to-hydrogen facility received the approval certificate for technological renovation projects in Guangdong Province (project code: 2103-440902-04-02-847747). The approval certificate number is 210902251130001, and the authority that issued the approval was the Science, Industry and Commerce Bureau of Maonan District, Maoming City. Main content of the project: It is planned to carry out technical upgrades aimed at improving the efficiency of raw material utilization and enhancing the use of oil residues in the coal-to-hydrogen facility located at the Maoming branch’s refinery. The upgrades include the installation of a new coal slurry concentration system ； Add storage and transportation of oil residues, as well as a flushing system for oils and pipelines ； 1 additional high-pressure ash water pump added ； Optimize the gasification burner, venturi scrubber, and refractory brick structure, and renovate the intermediate slag bin and related supporting facilities. Total project investment: 179.42 million yuan. This project aims to upgrade the existing 200,000 Nm3/h coal-based hydrogen production facility by modifying two gasifiers (Gasifier B and C). The feeding capacity of one gasifier is to be increased from 1,500 tons of dry coal per day to 1,680 tons per day, while the output of effective gas per gasifier is to rise from 105,000 Nm3/h to 125,000 Nm3/h. The feeding capacity of the other gasifier is to be adjusted from 1,500 tons of dry coal per day to 1,150 tons of coal plus 446 tons of oil sludge per day, with its output of effective gas per gasifier increasing from 105,000 Nm3/h to 135,000 Nm3/h. After the modification, the volume of the product gas increased from 200,000 Nm3/h to 248,000 Nm3/h (with the hydrogen stream rising from 188,000 Nm3/h to 236,000 Nm3/h). The production volume of isononanol synthesis gas (with CO and H2 as its main components), at 12,000 Nm3/h, remained unchanged; the by-products continued to be Claus gas (with CO2 and H2S as its main components) and carbon dioxide gas. The existing 200,000 Nm3/h coal-based hydrogen production plant is a sub-project of the oil product quality improvement project at the Maoming branch. It uses coal and petroleum coke as raw materials, and goes through various processes such as slurry preparation (where petroleum coke and raw coal are converted into suitable slurry in a slurry preparation unit), gasification (where the slurry, along with oxygen supplied by an air separation unit, enters the gasifier in the gasification unit where an oxidation reaction takes place; the resulting crude synthesis gas mainly consists of hydrogen, carbon monoxide, and carbon dioxide), shift reaction (where the crude synthesis gas enters a carbon monoxide shift unit where a shift reaction between carbon monoxide and water vapor occurs, producing hydrogen and carbon dioxide), removal of acidic gases (using low-temperature methanol washing technology to remove acidic gas components such as CO2 and H2S from the process gas through physical absorption and desorption at different temperatures), and methanation (where carbon, carbon monoxide, carbon dioxide, and hydrogen react to produce methane and water vapor; the water vapor is then condensed and separated through cooling, yielding hydrogen free of other impurities other than methane). The oil quality improvement project at the Maoming branch was approved by the former **Ministry of Environmental Protection on December 9, 2010, with the issuance of the approval document regarding the environmental impact assessment report for this project (Document No. Huan Shen [2010] 406). On July 5, 2016, it received the letter from the Guangdong Provincial Department of Environmental Protection containing its opinions on the environmental acceptance of the pollution control facilities installed as part of this oil quality improvement project (Document No. Yue Huan Shen 340). 2. Necessity of project construction: On December 31, 2020, the 2.6 million tons per year slurry-bed residue hydrogenation unit at Sinopec Maoming Petrochemical was put into operation successfully. This unit utilizes the ENI-EST process technology from Italy, and it is capable of efficiently converting heavy and low-quality crude oils into clean petroleum products. It boasts significant technical advantages such as strong conversion efficiency and high yields of light oils; it can also better adapt to changes in the properties of raw materials, thereby enabling optimization of the product structure. The 18.59 t/h of oil sludge produced by this device features high viscosity, high ash content, high impurity content, a complex composition, and difficulty in treatment. Therefore, it is an urgent task to find a suitable destination for the oil sludge produced by the slurry-bed residue hydrogenation unit within the refinery. There are various methods for recycling the oil sludge from the slurry bed residue oil unit, including: ① feeding it to a coking unit as raw material, ② using it as fuel in CFB boilers, and ③ sending it to a coal-to-hydrogen plant for co-gasification with coal. From a long-term operation perspective, sending the oil sludge from the slurry bed residue oil unit to the coking unit is not the optimal solution. Through research, comparison, and analysis, it has been found that the by-product oil sludge from the slurry-bed residue hydrogenation unit of Sinopec Maoming Branch currently, when fed into the coking unit, causes issues such as high residual carbon levels in the coker output, unsatisfactory ash content in the coke, and abnormal metal content in the products. Redirecting the oil residue to the coal-based hydrogen production facility not only increases the hydrogen yield per unit of oil residue but also reduces the overall cost of hydrogen production in the plant, while enabling efficient recovery of the precious metals contained in the oil residue. Therefore, from the perspectives of economics, technical feasibility, and environmental protection, using the oil residue from the paddle-bed residue hydroprocessing unit for coal-oil co-gasification in coal-based hydrogen production is the most viable approach for handling such residue. Therefore, the construction of this project is necessary. 3. Characteristics of project construction: Coal-kerosene coupled gasification makes full use of the high calorific value, low ash content, and high hydrocarbon content of oil residues as raw materials, as well as the advantages of gasification reactions in terms of low specific oxygen consumption and low specific fuel consumption. By leveraging the capacity of existing gasification equipment and the oxygen supply capability provided by air separation systems, this approach enhances the effective oxygen supply capacity of the installation through the coupled gasification of oil residues and coal slurry. Two of the three water-coal slurry gasifiers in the existing coal-to-hydrogen plants were modified for kerosene-assisted gasification; after the modification, each gasifier is capable of processing 18.59 t/h of oil residue. At the same time, to further increase the gas production of existing coal-to-hydrogen plants and reduce the specific coal consumption and specific oxygen consumption, the existing coal slurry preparation system was modified with a coal slurry concentration enhancement system, raising the slurry concentration by 2 percentage points from 60% to 62%. To achieve the separate recovery of the coarse slag generated by kerosene-coupled gasification, the original slag transportation system was modified for the separate recovery of coal slag. 4. Project Conclusion: During the operation period of this project, various pollutants such as wastewater, waste gas, and noise are treated through various environmental protection facilities and measures before being discharged in compliance with standards, while solid waste is disposed of safely. After implementing the appropriate preventive and mitigation measures, there will be little impact on the atmosphere, surface water, groundwater, sound environment, and soil; thus, the environmental risks associated with the project are at an acceptable level. According to the results of the public participation survey, during the first and second online announcements, as well as the announcements in newspapers and on-site postings, neither the project developer nor the environmental impact assessment agency received any feedback from the public regarding this project, nor were there any complaints from the public. Therefore, as long as the project developer strictly complies with **relevant environmental protection regulations and earnestly implements the various environmental protection measures and environmental risk prevention measures proposed in this report, the project is feasible from an environmental protection perspective.