The CANSOLV SO2 Scrubbing Sytem and the TGT+ system can be used in many areas of the refinery or gas plant;
- Fluid Cokers
- Fluid Catalytic Crackers
- Resid Fuel Fired Boilers
- Sulphur Recovery Units
- Process Heaters, Furnaces and Boilers
- Satellite Sulphuric Acid Plants
- Gasification Units
FCCU / FCU Units
The regenerable CANSOLV SO2 Scrubbing System is an ideal solution for refineries that are facing stricter sulphur emissions limits to air and water and that do not hydrotreat the FCCU/FCU feed or wish to take advantage of higher sulphur feedstocks.
It generates minimal effluent and allows the SO2 to be recovered as sellable sulphur or sulphuric acid. This can be achieved with minimal investment in the existing sulphur recovery unit (SRU) or in a single absorption sulphuric acid plant (SAP). The captured SO2 is pure and concentrated and can also be used to de-bottleneck the existing SRU capacity.
Sulphur Recovery Units
Modern upstream and downstream SRUs now require sulphur recovery efficiencies at levels higher than 99.9% and World Bank standard SOx emissions of less than 150mg/Nm3.
The highly efficient CANSOLV TGT+ system is an SRU tail gas treating unit (TGTU) that complements a new or existing SRU in upstream and downstream applications. Rather than reducing residual SO2 back to H2S, the residual tail gas is oxidized in an incinerator along with any other sour streams.
SO2 captured from the incinerator flue gas by the CANSOLV system, is recycled to the front end of the SRU, which reduces the amount of air required in the SRU to combust H2S into SO2.
The consequential reduction in overall inert gas load enables more sulphur throughput or a smaller SRU and also eliminates the need for oxygen enrichment. It complements Shell’s SULFINOL-X acid gas recovery unit technology which maximizes the removal of mercaptans from the natural gas and directs them to the SRU.
Process Heaters, Furnaces & Boilers
Refiners may wish to burn heavy fuel oil (HFO) and petroleum coke (petcoke) to generate their net energy demand and to provide another outlet for the ‘bottom of the barrel’.
The CANSOLV SO2 Scrubbing System will be most interesting to refiners who have insufficient residue oil upgrading capacity, that are faced with rising gas prices and are impacted by the Marpol Annex VI regulations governing the sulphur content in bunker fuel oil.
HFO can either be burnt in purpose built co-generation power units or in existing refinery units by modifying burners and implementing fuel oil heating systems.
Burning HFO and petcoke, however, will often produce high SOx emissions and conventional scrubbers rely on expensive caustic reagents and generate large amounts of dissolved solids and waste water effluent.
The CANSOLV SO2 Scrubbing System can achieve strict emission compliance while delivering a pure SO2 stream for conversion into sellable sulphur or sulphuric acid. It offers refiners another outlet for cracked residue streams and petcoke to harness power by using them as internal refinery fuel.
Satellite Sulphuric Acid Plants
Sulphuric Acid Plant (SAP) tail gas desulphurization has long been dominated by alkali reagent type processes, which convert the SO2 to calcium or sodium sulfate, creating aqueous and solid wastes that contribute to landfill tonnage and expense.
The disposal expense of these by-products is eliminated by installing a CANSOLV SO2 Scrubbing System. The by-product of a Cansolv plant is a pure water-saturated gaseous SO2 stream.
This SO2 is recycled to the existing drying tower at the front end of the acid plant for conversion to additional sulphuric acid, thereby enhancing capacity and maximizing resource recovery.