Technical Description of Parameters Influencing the pH Value of Suspension Absorbent Used in Flue Gas Desulfurization Systems

Abstract

As a result of the large limestone deposits available in Poland, the low cost of reagent acquisition for the largescale technological use and relatively well-documented processes of flue gas desulfurization (FGD) technologies based on limestone sorbent slurry, wet scrubbing desulfurization is a method of choice in Poland for flue gas treatment in energy production facilities, including power plants and industrial systems. The efficiency of FGD using the above method depends on several technological and kinetic parameters, particularly on the pH value of the sorbent (i.e., ground limestone suspended in water). Consequently, many studies in Poland and abroad address the impact of various parameters on the pH value of the sorbent suspension, such as the average diameter of sorbent particles (related to the limestone pulverization degree), sorbent quality (in terms of pure calcium carbonate [CaCO 3 ] content of the sorbent material), stoichiometric surfeit of CaCO 3 in relation to sulfur dioxide (SO 2 ) absorbed from flue gas circulating in the absorption node, time of absorption slurry retention in the absorber tank, chlorine ion concentration in sorbent slurry, and concentration of dissolved metal salts (Na, K, Mg, Fe, Al, and others). This study discusses the results of laboratory-scale tests conducted to establish the effect of the above parameters on the pH value of limestone slurry circulating in the SO 2 absorption node. On the basis of the test results, a correlation equation was postulated to help maintain the desirable pH value at the design phase of the wet FGD process. The postulated equation displays good coincidence between calculated pH values and those obtained using laboratory measurements.

Multimodel Anomaly Identification and Control in Wet Limestone-Gypsum Flue Gas Desulphurization System

“…In order to suppress the pollution brought by sulphur dioxide, the concentration of outlet flue gas along with a slurry pH value are selected as the controlled variables in our case study, and the former of which is a direct indicator that reflects desulphurization performance. Also, it has been verified that the pH value in slurry tank has a major influence on desulphurization efficiency [7].…”

Intelligent Partition of Operating Condition-Based Multi-Model Control in Flue Gas Desulfurization

“…As depicted in FIGURE 1, SO 2 concentration in desulfurized flue gas and pH value in slurry tank are measured by SO 2 concentration detector and pH meter respectively, both of which are key parameters in a WFGD system. To be specific, pH value in slurry tank closely correlates with the desulfurization efficiency [15] and outlet SO 2 concentration can best reflect the effectiveness of desulfurization. Thus, we select two of them as controlled variables in our work.…”

Influence of ammonia on wet-limestone flue gas desulfurization process from coal-based power plant

“…In such systems, limestone dosing is dependent on the pH measurement of the slurry. WFGD typically operate between pH of 5-6 [9], with the value pre-set in the master control system. Slurry pH is lowered by the absorption of gaseous acidic components and is adjusted by the addition of alkaline limestone (CaCO3) suspension.…”