FREQUENTLY ASKED QUESTIONS

1. What are the principal operating costs of the Cansolv Process?

In the Cansolv process, the biggest cost component is low pressure steam. In a typical application, the CANSOLV unit will condense between 5 and 8 percent of the steam in the power cycle at low pressure. The net impact on the power cycle will vary depending on the concentration of SO₂ in the flue gas, the extracted steam pressure and the energy integration schemes considered. Total pressure drop across a CANSOLV unit will be in the order of 10 inches of water (or 2.5Kpa(g)) so adequate fan capacity is required.

2. Are particulates a problem for the CANSOLV process?

Particulates need to be designed for in a Cansolv unit. CANSOLV units make use of structured packing to maximize mass transfer performance and adequately stage the SO₂ and CO₂ absorption processes. If the feed gas contains more than 30 mg/Nm³ (or 28 lb/hr) particulates, the prescrubber will be designed to provide additional particulate removal to meet the requirements.

3. Does a Cansolv unit require special abrasion or corrosion resistant materials?

The Cansolv process operates exclusively in liquid and gas phase so abrasion does not occur. For corrosion resistance in the SO₂ absorbtion process, 316L stainless steel is the most suitable alloy (process pH ¡Ü 5). FRP may also be used for the low temperature sections given the lack of abrasion. For the prescrubber section, a concrete shell and corrosion liner design is recommended as the pH drop to 1 depending on the concentration of strong acids in the gas (Cl, F, SO₃).

4. What happens to chloride, fluoride and other strong acids in a Cansolv Unit?

Strong acids will for the most part be removed in the prescrubber. The rate of removal will depend on the prescrubber design criteria. These acids will leave the unit in the prescrubber blowdown and can be neutralized with caustic in a water treatment step. The strong acids that slip into the CANSOLV SO₂ section will be removed in the amine purification unit and will not affect the solvent¡¯s efficiency in SO₂ capture. The amine purification unit will be designed for this.

5. Can CANSOLV processes be used for IGCC (gasification) emissions control?

CTI is an ideal solution for emissions control from IGCC sulfur plants.When properly integrated, Cansolv SO₂ tail gas scrubbing can be used to reduce inert load through the sulfur plant and avoid unwanted CO₂ recycle. A CANSOLV SO₂ tail gas unit can also value engineering flexibility for gasifier AGR design.

6. Does CTI provide turnkey solutions for SO₂ Scrubbing applications?

CTI typically provides a License and Process Design Package that is generated in sufficient detail to allow a competent engineering, procurement, construction contractor to develop a detailed design for a unit and to build it.  In some cases for smaller SO₂ Scrubbing applications, CTI is prepared to supply SO₂ Scrubbing modules, where the size of the modules are at or less than can be normally accommodated by local roads.  Contact us to explore this in detail.