FCC flue gas desulfurization

It seems that there are few industrial examples of this kind in the country; mainly, environmental protection standards have not yet been established for refineries.

Flue gas desulfurization is rarely mentioned in heavy catalytic units; maybe some do use it, but it’s really not necessary

The WGS flue gas desulfurization technology from Exxon Corporation that is being used by Jinxi Petrochemical consists of two main components: the wet gas scrubber (WGS) and the purification treatment unit (PTU). The flue gas first enters the WGS scrubber, where particles and SOX are removed. WGS mainly consists of a venturi tube and a separation tower. The alkaline liquid enters the venturi tube in the same direction as the flue gas; the washing liquid forms a thin film on the walls of the converging section, and then is divided into droplets at the inlet of the throat section. Due to the difference in relative velocities, inertial collisions occur between the gas and the droplets, and particles are captured in the throat section, while SOX is removed in both the throat section and the expanding section. Liquids and alkaline substances (such as NaOH) are fed directly into the separation tower, where the washing liquid is initially purified to maintain a balanced concentration of solids and dissolved salts in the system; thereafter, it is recycled. Part of this liquid goes to the PTU for further treatment, with the aim of reducing chemical oxygen demand and suspended solids to acceptable levels. The response so far is good. As for other companies, it’s not clear yet; LZ should check out a few more options, assess their performance overall, and then make a decision.

Flue gas desulfurization seems to be carried out using mobile systems over there; they generally use wet desulfurization methods

The environmental protection authorities require us to desulfurize the FCC flue gas by the end of this year; otherwise, fines will be imposed.

Luoyang Petrochemical Engineering Company possesses this technology, with patent number ZL96120045.6, and has relevant application records.

1# Clauspolunit FCC flue gas desulfurization: Currently, only Lanzhou Petrochemical and Yanshan Petrochemical in China have installed two units of this technology. Among the mature foreign technologies are Exxon’s WGS technology, BELCO’s EDV technology, and Dyna Wave reverse injection tower technology from Monmouth Corporation in the United States； In China, there are technologies such as the gas-liquid impact washing desulfurization technique developed by China University of Petroleum (Beijing), and the integrated catalytic flue gas desulfurization and dust removal technique developed by Guangzhou Tianci Sanhe Environmental Protection Engineering Company. All of these technologies employ sodium-based washing methods, using caustic soda or soda ash as absorbents; the resulting oxidation products are converted into Na2SO4 and discharged along with the wastewater. The removal rates for SO2 and dust can exceed 90%.

It was mentioned on the 4th floor that Jinxi Petrochemical has adopted WGS; I don’t know where that information came from. As far as I know, there is no 1# Clauspolunit there

The article titled “Problems and Countermeasures Regarding Sulfur Dioxide Emissions from Catalytic Cracking Units” published in March 1999 in Petroleum Refining and Chemical Engineering is worth reading.

After comprehensive comparison, our company ultimately chose the technology from American BELCO; construction is currently in progress, with completion planned for the end of the year.