【Haichuan Chemical Salary News】CNPC releases technology for producing aromatics through the alkylation of benzene and methanol

For petrochemical companies, the disproportionation and isomerization processes are more advantageous for producing p-xylene from benzene and toluene; the alkylation of benzene or toluene with methanol to produce p-xylene has little practical value. It is understood that in December 2012, Sinopec Yangzi Petrochemical successfully put into operation an industrial demonstration plant for the production of p-xylene via toluene methanol alkylation, with a capacity of 200,000 tons per year. However, not long after the technical evaluation was completed, this plant ceased operations, while the existing aromatic hydrocarbon disproportionation and isomerization plants continued to function. For coal chemical enterprises or coal-tar refining companies, especially those with coking units (that produce coking benzene and toluene) or those planning to build units for the production of aromatic compounds from coal, the technology of alkylating benzene or toluene with methanol to produce p-xylene holds significant practical value for altering the product portfolio and increasing added value.

Can methanol from coal chemical industry be utilized?

It depends on whether this company gives priority to its own interests, or focuses on upholding its corporate philosophy by helping other companies find ways to utilize methanol as its primary goal. Therefore, for coal chemical enterprises or coal-oil co-processing enterprises, it is of great practical significance to change their product structure, utilize the methanol produced internally, and employ the alkylation of benzene or toluene with methanol to produce p-xylene.

In the Midwest, there may be a larger market for technological applications, as there are many companies that produce coal-based methanol there.

A new technology for p-xylene production – toluene-methanol alkylation; technology transfer began in 2016. Toluene and methanol alkylation is a highly competitive technology for p-xylene (PX) production that has emerged in recent years. The most attractive feature of this process is that the PX yield is twice as high as that of the traditional toluene stereoselective disproportionation process. It also has many advantages: the amount of toluene required to produce 1 ton of PX product can be reduced from about 2.8 tons in the toluene stereoselective disproportionation method to 1.1 tons ； The price of raw material methanol is relatively low. Therefore, the PX production process via selective alkylation of toluene methanol is expected to become an important component of modern integrated aromatic plants. In September 2016, Shaanxi Coal Chemical Technology Engineering Center Co., Ltd. completed the signing of the first process licensing contract in Shandong for a new p-xylene production technology that it developed independently and for which it holds complete independent intellectual property rights. The new technology for p-xylene production uses toluene and methanol as raw materials, employing a circulating fluidized bed process to manufacture p-xylene. In November 2015, scale-up test studies at a hundred-ton scale for this technology were completed. The results of the 72-hour on-site evaluation showed that the one-pass conversion rate of toluene was 51.77%, the one-pass conversion rate of methanol was 98.94%, and the selectivity for p-xylene was 85.73%. Compared with traditional petrochemical p-xylene production processes, this technology features high selectivity for the target product p-xylene and flexible adjustability of the product profile ； Furthermore, this technology features continuous catalyst regeneration, stable product distribution, and a high raw material conversion rate. The signing of the first process licensing contract for the new technology in p-xylene production represents an important step forward in the commercial application of this technology. It indicates that all stages, from laboratory research and industrial-scale testing to market sales, have been completed. More importantly, it provides a clear direction for the subsequent development and production of catalytic materials. Preliminary estimates suggest that using this technology to produce p-xylene will reduce the cost per ton of product by 500–1,000 yuan compared to traditional petroleum-based methods, offering significant economic advantages. Moreover, the application of this technology enables an organic integration of coal chemical and petroleum chemical processes, opening up new production pathways for p-xylene. In December 2012, Sinopec Yangzi Petrochemical successfully commissioned an industrial demonstration plant for the production of p-xylene via toluene-methanol alkylation, with a capacity of 200,000 tons per year. By leveraging the strengths of Sinopec, Yangzi Petrochemical, the Shanghai Research Institute of Petrochemistry, and Luoyang Engineering Company, Sinopec has effectively integrated resources from various disciplines such as catalyst development, process research, and engineering design. It has completed industrial pilot tests as well as the development and design of a process package with an annual capacity of 200,000 tons. High-performance toluene methylation catalysts, multi-bed reaction processes, wastewater treatment systems, as well as heat integration and low-temperature heat utilization technologies have all been successfully developed. In addition to toluene-methanol alkylation, alkylation techniques for benzene and methanol are also under development. Public information from November 2016 indicated that the benzyl alcohol alkylation testing facility at the R&D institute of Urumqi Petrochemical Company had entered the industrial testing phase; once put into use in 2018, this equipment could generate annual revenues of 500 million yuan for the company.

New process for p-xylene production: The moving-bed technology for producing p-xylene from toluene and methanol while simultaneously generating low-carbon olefins (DTMPX) has been approved. Original article by Yang Shaoxing, Modern Coal Chemical Industry. December 3, 2018. On November 30, 2018, the China Petroleum and Chemical Industry Federation organized experts in Beijing to hold an evaluation meeting on the scientific and technological achievements of the “Moving-bed technology for producing p-xylene from toluene and methanol while simultaneously generating low-carbon olefins (DTMPX)”, which was developed jointly by the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and Shaanxi Yanchang Petroleum (Group) Co., Ltd. Li Yongwu, President of the Third Council of the China Petroleum and Chemical Federation, Hu Guangfa, Chief Engineer of Yanchang Petroleum Group Company, and Cai Ruichu*, Deputy Director of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, attended the meeting and delivered speeches. The 11 experts on the evaluation committee, headed by Academician Jin Yong from Tsinghua University, with Academician Wang Xieqing from Sinopec Research Institute of Petroleum Processing and Academician Yang Qiyeh from Sinopec Engineering Construction Co., Ltd. serving as deputy heads, deemed that this technology features the following innovations: First, catalyst shape-selective modification techniques and molecular sieve-type moving-bed pellet preparation techniques were developed, resulting in a specialized moving-bed catalyst (DXY-01) for the production of p-xylene from toluene and methanol alongside low-carbon olefins, whose various physical and chemical properties meet the requirements of moving-bed processes ； Secondly, a moving-bed reactor with independent intellectual property rights, as well as a moving-bed process for the production of p-xylene from toluene and methanol without the use of hydrogen, were developed. The plant’s process design is rational, and the reaction-regeneration system as well as the catalyst lifting and circulation system operate smoothly ； This achievement has resulted in 18 authorized patents (including 16 invention patents), possessing independent intellectual property rights. The evaluation committee unanimously agreed that the technology is highly innovative, with its overall level reaching international leading standards. This technology has established the world’s first 10,000-ton-scale industrial pilot plant using toluene and methanol to produce p-xylene along with low-carbon olefins, based on a moving-bed system. Through industrial trials, a series of technical achievements have been obtained, including the industrial production of catalysts specifically designed for moving-bed reactors, basic data for the design of process packages for industrial-scale installations, as well as plans for starting up, shutting down, and operating such installations. These achievements have laid a solid technical foundation for the construction and operation of industrial demonstration plants. From September 20 to 23, the China Petroleum and Chemical Industry Federation organized an on-site evaluation team to go to the Yan’an Petrochemical Plant to conduct a 72-hour continuous operation test of the moving-bed industrial test unit for the production of p-xylene from toluene methanol along with low-carbon olefins (Figure 3). The results of the on-site evaluation showed that the one-pass conversion rate of toluene was 26.42%, and p-xylene accounted for 90.79% by weight in the mixed xylenes. p-Xylene is one of the most fundamental raw materials in the organic chemical industry. In 2017, China’s consumption of p-xylene was 24.84 million tons, with 14.438 million tons imported, resulting in an import dependence rate of 58.1%. The success of this project not only achieves a combination of petrochemical and coal/natural gas chemical processes in the production of p-xylene, but also provides a new route for producing ethylene and propylene from coal/natural gas via methanol. Moreover, it enables the supply of the two basic raw materials required for polyester production—p-xylene and low-carbon olefins—in a single facility, bringing significant economic and social benefits.

How can we find ways to integrate coal chemical industry with the petroleum chemical industry, in order to diversify the products and focus on those that are more profitable in the future: lol

This might also be a long-term strategic consideration; it would be good if it could proceed to pilot-scale testing