Your benefits

In dry sorbent injection (DSI) our enhanced-reactivity products enable efficient pollutant removal without the use of water. This is in contrast with water-intensive systems like wet scrubbers or spray dry absorbers. It makes DSI particularly advantageous in regions with water scarcity.

When considering capital cost of equipment, efficiency of enhanced sorbents, and operational flexibility, most often we can offer the lowest overall cost solution to our customers.

Compared to other FGT technologies, a DSI unit requires limited investment and only a brief downtime for installation. It is a simple add-on to an existing process.

A DSI process utilizing hydrated lime consists of blowing a ready-to-use dry powder into a gas stream. Its operation therefore consumes only a small amount of power, as additional milling of the powder is not required.

In CDS units; the improved flowability of Sorbacal^® CDS particularly at high water content reduces pressure drop over the bag filter. Thus reducing the power consumption of the ID fan(s). Cleaner equipment surfaces with use of Sorbacal^® CDS will also contribute to long term power savings. The energy savings increase the overall plant efficiency or production capacity can be increased.

Unlike most other systems, DSI permits rapid dosage modification: from 0 to 100% in just minutes. This enables quick response to peak level changes due to different fuel quality or other process changes. “Peak shaving” increases efficiency and lowers the costs of pollutant capture. This is particularly useful for combined processes, for instance DSI with a spray dry absorber. A DSI system can also easily be switched on and off, a useful feature for power plants with large load swings.

In CDS processes, acid gas removal efficiency also correlates with water content of recirculating residue. Therefore peak control via water injection rates is possible especially with Sorbacal^® CDS.

Our Sorbacal^® sorbents can be mixed with activated carbon  for combined acid gas removal and micro-pollutant capture (e.g. vapor-phase mercury, dioxins, furans). In this way only one DSI system is required and costs are reduced. The blends are tailored depending on the customer's flue gas composition.

When acid gases such as SO₃ and HCl cool to their dew points in the presence of moisture, very corrosive compounds are created that damage ducts and air pollution control systems.
Residues may also build-up on the internal surfaces of process equipment (ducts, vanes, etc) in particular with CDS systems due to the recirculation of residues.  This not only reduces process efficiency but can also lead to corrosion issues especially if significant accumulation occurs.
Our highly reactive Sorbacal^® sorbents with good flowability ensure effective capture over a wide range of temperatures with minimal dust accumulation, lowering duct corrosion.

Ammonia is typically used in NO_x control systems using selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) technology. In particular, the formation of ammonium bisulfate (NH₄)HSO₄ or ABS can foul air heaters and electrostatic precipitators. Sorbacal^® sorbents used prior to the air heater and ESP remove SO₃ and prevent the formation of ABS. Additionally, removing acidic components lowers dewpoint to improve heat rate thus boosting efficiency and cutting costs.

Selective catalytic reduction (SCR) systems are used to lower NOx in, for example, coal-fired boiler gas streams. Gaseous arsenic released through coal combustion can deactivate the DeNOx catalyst. Adding small amounts of limestone (CaCO₃) or quicklime (CaO) to the fuel or DSI with hydrated lime prior to SCR reduces the gaseous arsenic in the flue gas. This decreases its harmful effect on the catalyst, boosting the efficiency of NOx capture and lowering costs. In addition, minimum SCR operating temperature could be reduced.

Typically, dry sorbents based on powdered activated carbon (PAC) are used in mercury control applications. It is known that SO₃ in the flue gas stream increases carbon consumption, as it competes with mercury in the activated-carbon capture sites. Sorbacal^® injected upstream of the carbon injection captures the SO₃, thus reducing PAC consumption and mercury control costs.

When considering dry processes you may want to compare the costs of calcium and sodium sorbents. It is critical to do this on a mass consumption basis. This can be illustrated by contrasting Sorbacal^® calcium hydroxide (Ca(OH)₂) with trona. For the same molar consumption, the actual consumption on a weight basis is dramatically higher for the sodium sorbent due to the difference in molecular weight: 226 (g/mol) for trona vs. 74 (g/mol) for Sorbacal^® calcium hydroxide. By estimating the sorbent cost on a weight basis, the actual sorbent cost-per-ton of acid gas captured may be calculated. Similar calculations can be done for sodium bicarbonate.

Unlike Sorbacal^® calcium hydroxide (Ca(OH)₂) sorbents, most sodium sorbents – for example sodium bicarbonate – typically require on-site milling, which is necessary to produce sufficiently fine powder for flue gas treatment. An on-site mill adds capital, power, and maintenance cost to the flue gas treatment process.

The use of sodium-based sorbents produces sodium sulfate, which is very soluble. By contrast, Sorbacal^® calcium-based products create less-soluble calcium sulfate. The resulting fly ash may comply with leaching limits, helping to avoid landfill costs and possibly enabling its use in soil stabilization and increasing its resale value. Moreover, high sodium content in fly ash may prevent its use in cement and concrete applications.

We provide sorbents with the highest purity and whiteness. The higher whiteness increases the resale value of the gypsum generated from wet flue gas desulfurization.

Compared to standard hydrates, the high performance of our Sorbacal^® sorbents lowers consumption. This generates fewer residues and has a positive impact on the direct and indirect operational costs of flue gas treatment.

Because of the high performance of Sorbacal^®, the refill frequency of the silo is lower than with standard sorbents. This optimizes logistics and allows a silo with a smaller volume.

The superior flowability of Sorbacal^® CDS minimises any accumulation of residues on surfaces. Therefore increasing run time by extending maintenance cycles.

The high performance of Sorbacal^® SP and SPS means consumption is significantly lower than that of standard hydrates. This results in a slower build-up of residue in the filter sleeves and thus less-frequent filter cleaning.

In CDS processes, high moisture content combined with Sorbacal^® CDS leads to lower pressure drop over the bag filters due to improved flowability. For both applications, the reduced stress on the filter sleeve materials significantly increases their lifetime.

Our Sorbacal^® products are highly effective in capturing HCl from the flue gas. Injecting Sorbacal^® sorbents before a wet scrubber results in an increased chloride capture, and therefore reduced wet scrubber blowdown.

Removal of heavy metals (e.g. selenium, arsenic) from the waste water of wet scrubbers will become a future topic for utility operators. Dry sorbent injection (DSI) of Sorbacal^® SP or SPS is very effective in removing selenium (SeO₂) and arsenic from the gas phase. Injecting Sorbacal^® SP or SPS upstream of the electrostatic precipitator (ESP) will reduce the selenium concentration in the wet scrubber waste water and may eliminate water treatment.

A DSI unit is technically a simple system consisting of a silo, dosing unit, blowers and in-duct injection lances. It therefore requires only a small footprint in the existing plant.

The improved flowability of Sorbacal^® minimizes any build-up of material on surfaces within the FGT system (reactor, ducts, etc). Thus reducing maintenance cost and frequency. This is especially important for CDS units due to the recirculation of residue. 

Sorbent Consumption reduction

The high pore volume and surface area of our Sorbacal^® SP and SPS sorbents make them much more efficient at acid gas removal than standard hydrated limes. Laboratory tests, pilot scale demonstrations and commercial experience all show that Sorbacal^® SP can be twice or more as active as standard hydrated lime. This reduces the fresh sorbent by at least half and also generates fewer residues (see illustration).

Real flue gas removal of SO₂ - performance curve of 3 types of Sorbacal^® sorbents

The curve depends on the operating conditions and gas composition. Our experts can simulate performance curves representing your specific application in order to calculate the Sorbacal® sorbent consumption. The graph shows different dosing rates for the same SO₂ removal.

Tighter emission limits

The high pore volume and surface area of our Sorbacal^® SP and SPS sorbents make them much more efficient at acid gas removal than standard hydrated limes. Sorbacal^® SP can be twice as active as standard hydrated lime. This enables to reach tighter emission limits than with standard hydrate. For most applications Sorbacal^® SPS is about 30% more active than Sorbacal^® SP, and thus capable of achieving even tighter limits (see illustration).

Real flue gas removal of SO₂  - performance curve of 3 types of Sorbacal^® sorbent

In some processes the intake air is pre-heated with flue gas. The removal of SO₃ prevents formation of acid and enables a more efficient heat transfer between flue gas and the intake air.

Unlike most other systems, DSI permits rapid dosage modification: from 0 to 100% in just minutes. This enables quick response to peak level changes due to different fuel quality. “Peak shaving” increases efficiency and lowers the costs of pollutant capture. This is particularly useful for combined processes, for instance DSI combined with a spray dry absorber. A DSI system can also easily be switched on and off, a useful feature for power plants with large load swings..

In a DSI process the flue gas temperature is not affected, enabling higher heat recovery and increased process efficiency.

Our optimized particle size is small enough for high reactivity, yet large enough for efficient particulate removal in electrostatic precipitators (ESPs). In bag filters our particle size prevents a too-high pressure drop. This avoids higher power and maintenance costs and shortened filter-bag life.  Additionally, our the optimized particle size means our products are engineered for good flow behavior, minimizing transportation issues in the silo and dosing systems. This reduces the risk of exceeding emissions limits due to a clogged system, and lowers operational and maintenance costs.

Sorbacal^® SPS has a higher electrical conductivity than regular hydrated lime, as well as an optimized particle size. This makes the product compatible with electrostatic precipitator (ESP) systems. The high reactivity of SPS leads to better SO₂ control without increasing particle emissions from the ESP.

Our highly reactive Sorbacal^® sorbents require lower consumption for a given acid-gas capture rate. This reduces the filter load and therefore particulate emissions.

Ammonia is typically used in NOx control systems using selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) technology. In particular, the formation of ammonium bisulfate (NH₄)HSO₄ or ABS can foul air heaters and electrostatic precipitators. Sorbacal^® sorbents used prior to the air heater and ESP remove SO₃ and prevent the formation of ABS. Additionally, removing acidic components lowers dewpoint to improve heat rate thus boosting efficiency and cutting costs.

Selective catalytic reduction (SCR) systems are used to lower NO_x in, for example, coal-fired boiler gas streams. Gaseous arsenic released through coal combustion can deactivate the DeNOx catalyst. Adding small amounts of limestone (CaCO₃) or quicklime (CaO) to the fuel or DSI with hydrated lime prior to SCR reduces the gaseous arsenic in the flue gas. This decreases its harmful effect on the catalyst, boosting the efficiency of NOx capture and lowering costs. In addition, minimum SCR operating temperature could be reduced.

Typically, dry sorbents based on powdered activated carbon (PAC) are used in mercury control applications. It is known that SO₃ in the flue gas stream increases carbon consumption, as it competes with mercury in the activated-carbon capture sites. Sorbacal^® injected upstream of the carbon injection captures the SO₃, thus reducing PAC consumption and mercury control costs.

Sorbacal^® SP and SPS are very effective at removing SO₃ in flue gas. Injection of Sorbacal_® SP or SPS prior to a selective catalytic reduction (SCR) unit lowers the risk of ammonium bisulfate formation. This allows the SCR to operate at a lower temperature, which increases the catalyst lifetime.

Some sodium-based sorbents will emit NO_x during their reaction in the flue gas. These nitrogen oxides can adsorb on the surface of powdered activated carbon (PAC) thus reducing their efficiency for mercury capture. Sorbacal^® sorbents will not generate NO_x in your installation.

While some sodium reagents used in flue gas treatment emit CO₂ through their reaction with acid gases, hydrated lime captures CO₂ in the process. Even if usually limited, the impact on customer’s CO₂ emissions is positive.

In dry sorbent injection (DSI) our enhanced-reactivity products enable efficient pollutant removal without the use of water. This is in contrast with water-intensive systems like wet scrubbers or spray dry absorbers. It makes DSI particularly advantageous in regions with water scarcity.

Compared to other FGT technologies, a DSI unit requires limited investment and only a brief downtime for installation. It is a simple add-on to an existing process.

A DSI unit is technically a simple system consisting of a silo, dosing unit, blowers and in-duct injection lances. It therefore requires only a small footprint in the existing plant.

Unlike most other systems, DSI permits rapid dosage modification: from 0 to 100% in just minutes. This enables quick response to peak level changes due to different fuel quality or other process changes. “Peak shaving” increases efficiency and lowers the costs of pollutant capture. This is particularly useful for combined processes, for instance DSI with a spray dry absorber. A DSI system can also easily be switched on and off, a useful feature for power plants with large load swings.

Our Sorbacal^® sorbents can be mixed with activated carbon  for combined acid gas removal and micro-pollutant capture (e.g. vapor-phase mercury, dioxins, furans). In this way only one DSI system is required and costs are reduced. The blends are tailored depending on the customer's flue gas composition. The blends are tailored depending on the customer’s flue gas composition.

The injection of powdered activated carbon (PAC) can result in hot spots in the bag filter. It may also require special explosion-proof storage and dosing equipment. Our blends of Sorbacal^® and PAC mitigate the risk of explosion and fire.

Lhoist products are engineered for good flow behavior, minimizing transportation issues in the silo and dosing systems. This reduces the risk of exceeding emissions limits due to a clogged system, and lowers operational and maintenance costs.

Some sodium-based sorbents will emit NO_x during their reaction in the flue gas. These nitrogen oxides can adsorb on the surface of powdered activated carbon (PAC) thus reducing their efficiency for mercury capture. Sorbacal^® sorbents will not generate NO_x in your installation.