Reduction of fine particulate matter emissions from cornstalk combustion by calcium phosphates additives

• The emission of fine particulate matters with an aerodynamic diameter of less than 1 µm (PM1) is usually high from straw biomass combustion, resulting in great danger to atmospheric environment and public health. In this work, the effect of three calcium phosphate additives on PM1 emission from cornstalk combustion was investigated using a lab-scale reactor. The addition of Ca(H2PO4)2, CaHPO4 and Ca3(PO4)2 reduced PM1 emission by 1.5–50.6%, 22–55.6% and 23–53.7%, respectively. For Ca(H2PO4)2, PM1 reduction rate reached its maximum values of 50.6% at P/K molar ratio equal to 1 and then decreased significantly with further increasing of P/K molar ratio. For both CaHPO4 and Ca3(PO4)2, PM1 reduction rate increased approximately linearly with increasing the amount of additives under the current operating conditions. Analyses of the collected particulate matters and residual ashes indicated that phosphorus was mainly transformed into PM1-10 and residual ash in the form of K-Ca/Mg phosphates and Ca/Mg phosphates, respectively. The PM1 reduction mechanism was proposed based on the characterization results. Finally, economic analysis showed that the addition of Ca3(PO4)2 is a potentially promising method to reduce PM1 emissions during straw biomass combustion. 

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Keyword

Additive

Combustion

Phosphate

PM emissions

Straw biomass

Publication and Content Type

ref (subject category)

art (subject category)