Seeking a shutdown and startup plan as well as operating procedures for sulfolane-based aromatic extraction

The poster is referring to the technology from the Institute of Rock Mechanics, I know something about it, but not everything; it’s available on the forum and should be searchable

Where is it?:) :) :) Yes, are there any specific instructions or guidelines available??? This post was last edited by xzlnb on 2008-9-1 21:12.]

Light tar (COLO – Coke Oven Light Oil) is a by-product of the steel industry; since coke is used in steel production, light tar is produced as a by-product of coal coking. In 2006, China’s production of light tar was around 3.5 to 4 million tons, with benzene, toluene, and xylene accounting for over 90% of its composition (benzene making up 70–80%) ； Toluene 10 – 15% ； Xylene, styrene, and ethylbenzene account for 3–5% of its composition; COLO contains heterocyclic compounds such as pyridine (0.25%) and thiophene (0.3–0.6%), which result in sulfur and nitrogen impurity levels of several thousand, or even over 10,000 PPm. It also contains impurities such as mono- and polyolefins (1.5–2.5% styrene). It is not practical to separate these impurities—pyridine, thiophene, and styrene—from COLO using simple distillation methods, as their boiling points are very close to those of the desired products (benzene, toluene, xylene) (see table below). This limits the economic, efficient, and effective utilization of light tar. Traditional refining and recovery methods used in China not only result in low recovery rates for benzene, toluene, and mixed xylene but also cause severe environmental pollution, thereby hindering the development and utilization of light tar. The selective hydrogenation refining and sulfolane aromatic extraction technologies developed by the American company Lyondell for light tar (COLO – Coke Oven Light Oil) effectively address these challenges. These technologies not only transform low-value light tar into products with high added value but also ensure high product recovery rates (with yields of BTX reaching 97.5%, 97.5%, and 115% respectively – guaranteed values), as well as high purity levels (with purities of BTX at 99.95%, 99.8%, and 98.6% respectively – guaranteed values). The benzene, toluene, and xylene produced meet the requirements for use in various applications, while cyclohexane-grade benzene, methylcyclohexane, and TDI (toluene diisocyanate)-grade toluene can also be obtained. More importantly, these processes cause no environmental pollution, thereby promoting the development of the light tar chemical industry. Since the 1970s, Lyondell has licensed dozens of selective hydrogenation/cyclosulfone aromatics extraction technologies around the world for the hydrofining/aromatics extraction of catalytically reformed/petrolytic gasoline, to produce benzene, toluene, and xylene (BTX – Benzene, Toluene, Xylene). The first industrial plant to use Lyondell hydrogenation/aromatic extraction technology with COLO as raw material was operated by Japan’s Kawatetsu Chemicals company in 1982. The second set, also using COLO material, was produced by the Japanese company Adchemco in 1995. It is expected that industrial plants in China that will use Lyondell’s aforementioned technology with COLO as raw material will come online successively between 2008 and 2010. These users include Shanghai Baosteel, Jiangsu Shagang, Shenma Group (Pingdingshan, Henan), Shuncheng Group (Anyang, Henan), Baotou Steel, and Huaibei Mining Bureau, among others. Llyodell, drawing on its more than 20 years of experience in industrialization as well as relevant pilot-scale hydrogenation research results, is able to quantitatively adjust all major operating parameters, thereby providing new and existing customers with the latest technological advancements and catalyst improvements to bring benefits to them. Advantages of Lyondell’s selective hydrogenation technology: strong adaptability to the raw materials processed, and high flexibility. The designed unit can process different feedstocks (reformate, pyrolysis gasoline, coker light oil, and mixtures thereof). It can be designed to process 100% light tar feedstock, as well as mixtures of light tar with pyrolyzed gasoline or aromatics reformed oil. Due to this characteristic, in a plant designed using 100% light tar feedstock, the maximum proportion of pyrolysis gasoline or reformed oil in the mixed feedstock is approximately 35.0%. Unique Lyondell aromatics extraction technology: There are many different processes that can be used to extract aromatics from various light coal-tar and petrochemical products. To date, the most widely used technique is the liquid-liquid extraction method using sulfolane as the extractant. This process has been in successful use for over forty years, and it continues to be improved. Despite the introduction of other extraction processes and various solvents, the sulfolane-based systems provided by Lyondell (and UOP, among others) remain the preferred technology. Today, there are over 30 aromatic extraction units owned by Lyondell itself or those that use its transferred technology in operation, processing feedstocks such as coker light oil, hydrogenated cracked gasoline, reformed oil, and various mixtures of these. In fact, the Japanese Kawatetsu and Adchemco plants can process light tar feedstock alone, or a mixture of it with pyrolysis gasoline. Lyondell provides customized designs for each new aromatic extraction unit, constructing more flexible production facilities as required by each customer.