China's new technology for sulfur recovery has reached the world's leading level

“The sulfur dioxide content per cubic meter of flue gas in the fourth sulfur plant of Qilu Petrochemical Refinery is only 39-89 mg”. On July 9th, the final test results obtained by the researchers of Qilu Petrochemical Research Institute gave them unexpected surprises. This not only marks the success of the development of sulfur dioxide emission standard upgrading technology, but also the convincing data of sulfur dioxide emission concentration of less than 100 mg/m3, which makes our new technology of sulfur recovery undisputed reach the world. Leading level.

In March of this year, Qilu Petrochemical Refinery used maintenance opportunities to renovate the liquid stream degassing of the fourth sulfur plant. In the transformation, not only the newly developed low-temperature, oxygen-resistant and high-stability Claus tail gas hydrogenation catalyst was used, and the desulfurization waste gas was introduced into the hydrogenation reactor for treatment, and a high-efficiency desulfurization solvent was also used. Under the synergy of many parties, new technologies and new measures to reduce sulfur dioxide emissions have seen significant results in the sulfur plant. Since mid-April, the flue gas sulphur dioxide has been kept below the 100 mg/m3 emission standard, far below the world's most demanding California 143 mg/m3 emission standard, leading the world's advanced level.

China is about to implement new environmental regulations. The sulfur dioxide emission level of sulfur in the sulfur plant is less than 400 mg/m3, and the emission in special areas is less than 200 mg/m3. This standard places higher demands on sulfur recovery technologies and catalysts. In order to achieve this standard, in 2012, Qilu Petrochemical Research Institute began the development of a new process to reduce sulfur dioxide emissions from sulfur plants. Researchers work closely with refineries to play the “Four Steps” and apply a number of new technologies and new results to the production of the plant to minimize the concentration of sulfur dioxide in the flue gas.

The first step is to develop a new liquid sulfur degassing process. At present, the degassing waste gas from the sulfur stream is generally treated in an incinerator, which seriously affects the concentration of sulfur dioxide in the flue gas. The new liquid sulfur degassing process uses purified tail gas as the stripping gas for liquid sulfur degassing, and introduces the liquid sulfur degassed waste gas into the hydrogenation reactor, undergoes hydroconversion to hydrogen sulfide, and is recovered by the amine liquid to be returned to the sulfur unit for recovery. Elemental sulfur significantly reduces the concentration of sulfur dioxide in the flue gas. The second step is to use a high-efficiency desulfurizer. Most of the sulfur dioxide in the flue gas of the sulfur plant is derived from the hydrogen sulfide in the purified gas. The high-efficiency desulfurizer can reduce the hydrogen sulfide content in the purified gas to below 20 mg/m3 under certain conditions. The third step is to use a reasonable catalyst grading to maximize the catalytic reaction and reduce the organic sulphide content in the tail gas. The fourth step is to set the process control index reasonably and optimize the operation of the exhaust gas purification unit to reduce the sulfur dioxide emissions of the device.

The improvement of the process not only significantly reduces the concentration of sulfur dioxide in the sulfur plant, but also reduces the production cost per ton of sulfur by 50 yuan. According to Qilu Petrochemical's annual output of 210,000 tons of sulfur, the annual increase is 10 million. Above yuan.

[Editor: Chen Guofang]