Wet Lime Research Articles

Determination of Properties of Loose and Granulated Organic Fertilizers and Qualitative Assessment of Fertilizer Spreading

Precise and environmentally friendly fertilization is one of the most effective agrotechnical measures to improve crop yield, crop quality, and environmental sustainability. The aim of this study was to determine the uniformity of spreading of organic fertilizers on the soil surface at different flows by evaluating the influence of the physical and mechanical properties of the fertilizers. The physical properties of organic fertilizers have been found to have a significant impact on the uniformity of fertilizer distribution. The investigation of fertilizer properties showed that the average moisture content of meat and bone meal granular fertilizers was 8.6 ± 0.2%, of cattle manure granular fertilizers—14.9 ± 1.5%, of dry lime—9.4 ± 0.1%, of wet lime—17.0 ± 1.1%, and of manure—66.7 ± 6.9%. It was found that the granules of cattle manure were more evenly spread on the soil surface (Gaussian coefficient 0.46) than the granules of meat and bone meal (g2 = 7.11). At the same time, manure was found to be most evenly distributed on the soil when dry lime was spread more evenly than wet. Simultaneously, it was revealed that the physical properties of the fertilizer, such as higher moisture, lower mass, granule length, and width, affected the uniformity of fertilizer distribution on the soil surface.

Limestone Sorbents Market for Flue Gas Desulphurisation in Coal-Fired Power Plants in the Context of the Transformation of the Power Industry—A Case of Poland

Since the beginning of the 1990s, due to international regulations on air quality, a large number of flue gas desulphurisation (FGD) installations have been constructed in the Polish coal-fired power industry. Thanks to that, SO2 capture in this industry increased to ca. 90%. Since wet lime or fluidized bed boilers were mostly used for FGD purposes, a significant increase in the domestic demand for lime sorbents has been reported. Between 1994 and 2019, it has increased from virtually zero before 1994 to about 3.3–3.4 million tpy (tonnes per year) today. On the basis of official governmental data and completed surveys of the Polish power companies, the paper analyses the process of the implementation of FGD in Poland along with limestone sorbents consumption and FGD gypsum production in the Polish coal-fired power plants. It also presents the current and potential limestone resource base for production of limestone sorbents applied in FGD. Electric energy mix in Poland is expected to be changed radically in the coming 30 years. Share of coal-based electricity is still very high—ca. 80%—and it will remain dominant for at least next decade. With the next coming FGD installations, further moderate increase of limestone sorbents consumption is expected, up to 3.7 million tpy in 2030. After 2030, a significant, quick decrease of share of coal-fired electricity is expected in Poland, down to max. 30% just before 2050. This will result in a gradual decrease in limestone sorbent demand, to max. 1.3 million tpy before 2050 and virtually zero after 2050, which will be followed by collapse of FGD gypsum production.

Preliminary study on wind slaked lime used before Qing Dynasty in China

ABSTRACTHistoric lime mortars found in the masonry or architectural ruins before Qing Dynasty (1644–1912) show thicker bedding, higher strength, which may be related to the lime slaked by wind described by literature published before Qing Dynasty. The literature recorded that there existed two ways to slake lime: wind slaked and water slaked, which would have caused different properties. In order to assess the building lime properties slaked by wind, the quicklime produced by a lime manufacturer using traditional kiln techniques was collected, and then slaked by wind, mist spray and wet. The mineralogical studies show the calcium silicates like belite have been found both in quicklime and limes slaked by wind and mist. But no calcium silicates have been identified in the wet slaked lime. The lime slaked by wind has got higher strength, its compressive strength can reach 1.5 Mpa in 28 days stored in the indoor air climate, while it needs much shorter setting time. The preliminary results show that the performance of lime slaked by wind is similar to NHL2 classified by EN-459, if the quick lime is kilned from limestone with impurities. The wind slaked lime with higher strength and shorter setting time might have contributed to the magnificent constructions before Qing Dynasty in China. Both the literature and built heritage before the Qing Dynasty should be studied further. More comprehensive researches on wind slaking are needed in China in order to revitalise this traditional lime use combined with ancient wisdom for the economic conservation of built heritage in China.

EMISSION INTENSITY AND ABATEMENT COST OF FOSSIL FUEL POWER PLANTS IN THAILAND

Monitoring of air emission and pollution control cost is a key to improve air quality management of electricity generation industry. This research comprehensively evaluates abatement cost of sulfur dioxide (SO2), nitrogen oxides (NOx), emission intensity and emission inventory of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM), and carbon dioxide (CO2) emitted from Thailand s fossil fuel power plants. The research applied bottom-up approach with continuously monitored data from 64 percent of Thailand electricity generation industry. The data was used in an evaluation of emission intensity according to technology, fuel type and pollution control system. The research finding indicates that lignite-fired power plants are the major contributors of air pollution in Thailand. The research results will help in improving performance of emission forecast and monitoring via usage of site-specific emission factors. Air emission factors from power plants were found to be 0.022 1.432 g-SO2/kWh, 0.122 5.229 g-NOx/kWh, 0.031 g-PM/kWh, and 452 1,443 g-CO2/kWh. The cost for SO2 reduction from fossil fuel-based power plants are estimated to be 0.03-0.26 US$/Kg-SO2 while abatement costs of NOx are 0.31-9.63 US$/kg-NOx. Flue gas desulfurization with wet lime and dry low-NOx burner are more efficient and cost-effective in controlling SO2 and NOx than the other techniques. The research results were also benchmarked against available international data sources. The findings can be used in policy planning and decision making process of key stakeholders to help improve air quality in the future.

Лісівничо-екологічний аналіз насаджень Populus alba та Populus nigra на ріках лівобережного лісостепу України

<p>Here the sylvicultural and ecological analysis of typological structure of plantings silver and black poplar are presented for the riverine habitats of the Psel, Sula and Vorskla (the middle reaches of Seversky Donets river). Our analysis was based on forestry management electronic databases of Ukrainian National Forest Project Enterprise.</p><p>More than 38 forest types on the area of 4.9 thousand hectares were examined. The biological features of silver and black poplar were described briefly. The silver and black poplar reproduction pattern of the Left-bank Forest-steppe of Ukraine was also examined. There was carried out the area allocation of tree species according the following points: forest type and origin, forest site quality, closure degree and age groups. By the tree stratum origin silver and black poplar are mostly artificially propagated, what is equivalent to 77.3 and 88.3 percent.</p><p>The silver and black poplar area around the rivers’ watershed of the Left-bank Forest-steppe of Ukraine occupies 2813 and 2173 ha consequently.</p><p>Among forest types on research subject there are some forest types which dominate: fresh quercetum fluvialis (25.0 %), wet quercetum fluvialis (17.4 %), wet quercetum-birchbark-maple fluvialis (16.3 %), wet lime tree-oak-pine tree sudubrava (11.4 %), fresh lime tree, oak, pine tree sudubrava (5.2 %), the rest of tree types represents less than 4.0 % of the total land area, covered with sylva. The silver and black poplar plantings’ distribution according to the site quality of forest on the rivers’ columbine of the Left-bank Forest-steppe of Ukraine can be described in the following way: II and IV classes of the site quality of forest prevail, and the medium stocked tree stratum fluctuates from 52.9 to 87.8 per cent according to the normality.</p>

Wet Blue Fiber and Lime from Leather Industry Solid Waste as Stabilizing Additive and Filler in Design of Stone Matrix Asphalt

Wet Blue Fiber and Lime from Leather Industry Solid Waste as Stabilizing Additive and Filler in Design of Stone Matrix Asphalt

The Treatment and Recycling of FGD Waste

At present, wet lime - gypsum flue gas desulfurization (FGD) technology is very common in the field of gas desulfurization technology. In addition, wet carbide slag - gypsum FGD and Magnesia FGD are also used. In the process of eliminating SO2, with the first two technology, the byproducts of desulfurization wastewater and gypsum will be produced; With Magnesia FGD, the byproducts of magnesium sulfite and magnesium will be produced. The way to utilize desulfurization wastewater, gypsum and magnesium comprehensively and to achieve circular economy is worth exploring.

Sulphur isotope compositions of components of coal and S-isotope fractionation during its combustion and flue gas desulphurization

Sulphur isotope compositions were determined in two different Polish coals (hard coal and lignite) and by-products originating from their combustion. The desulphurization process was also investigated. It was demonstrated that desulphurization changes the isotopic composition of sulphur emitted in the form of SO2 to the atmosphere even if the process is conducted in a different way (wet lime technology and electron beam method). This fact has to be considered in the studies regarding anthropogenic sulphur genesis and its fate in the environment.

Comparison of flue gas desulphurization processes based on life cycle assessment

In this work, the environmental impact assessment is prepared for three different flue gas desulphurization (FGD) processes: (1) intra-furnace sulphur removal during coal combustion with limestone addition, (2) FGD with wet lime scrubbing, (3) regenerative copper oxide flue gas clean-up process. The evaluation and ranking of the three processes according to their environmental impacts is completed for the treatment of as much flue gas that contains 1 kg sulphur. The assessment of the environmental impacts is carried out with the Eco-indicator 99 life cycle impact assessment methodology based on life cycle inventories collected from existing coal fuelled power plants. The environmental assessment is prepared for three different scenarios according to degree of the utilization of the by-products obtained during the desulphurization: (1) zero utilization, (2) full utilization, (3) utilization according to industrial statistics. The results show that all the three investigated FGD processes have about 80% lower environmental impact than the uncontrolled release of sulphur oxides into air. Intra-furnace limestone addition and wet scrubbing processes use similar principal of physical chemistry and they have similar environmental indices. The basis of the regenerative process is a sorption/reduction/oxidation cycle that has higher SO2 removal efficiency than the two other processes. This higher efficiency results in a significantly lower environmental impact.

Anticorrosion technology of exhaust heating for wet lime dust-removal and desulfurization in coal-fired power plant

Anticorrosion technology of exhaust heating for wet lime dust-removal and desulfurization in coal-fired power plant

Fluid bed biological nitrification and denitrification in high salinity wastewater

Wastewater from wet lime(stone)-gypsum flue gas desulphurisation (FGD) processes in coal-fired power plants contains nitrate. Where case selective catalytic reduction (SCR) of NOx is applied the wastewater can also contain ammonia. For the removal of both nitrate and ammonia, biological processes are an attractive option. A bottle-neck for application of biological processes might be the high chloride concentration and relatively high temperature of the wastewater. Therefore research work was performed in fluid-bed reactors at pilot-plant scale for both biological nitrification and denitrification. Biological nitrification was studied up to 34 gCl−/l and nitrite was the main product formed. Biological denitrification was effective up to at least 45 gCl−/l. Both nitrate and nitrite were removed effectively.

Fluid bed biological nitrification and denitrification in high salinity wastewater

Wastewater from wet lime(stone)-gypsum flue gas desulphurisation (FGD) processes in coal-fired power plants contains nitrate. Where case selective catalytic reduction (SCR) of NO x is applied the wastewater can also contain ammonia. For the removal of both nitrate and ammonia, biological processes are an attractive option. A bottle-neck for application of biological processes might be the high chloride concentration and relatively high temperature of the wastewater. Therefore research work was performed in fluid-bed reactors at pilot-plant scale for both biological nitrification and denitrification. Biological nitrification was studied up to 34 gCl − /l and nitrite was the main product formed. Biological denitrification was effective up to at least 45 gCl − /l. Both nitrate and nitrite were removed effectively.

Removal of heavy metals and suspended solids from wastewater from wet lime (stone)—gypson flue gas desulphurization plants by means of hydrophobic and hydrophilic crossflow microfiltration membranes

Wastewater from wet lime (stone)—gypsum flue gas desulphurization plants (FGD) for coal-fired boilers contains suspended solids (fine gypsum, silica, hydroxides of iron and aluminium) and soluble salts (chlorides and sulphates of calcium, sodium and magnesium). Moreover, traces of heavy metals such as As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, and Zn are present in these wastewater streams. Most of these heavy metals and suspended solids have to be removed before discharging the wastewater, in order to fulfil the demands stated by the Dutch authorities. Therefore, a very efficient treatment method, based on coprecipitation of heavy metal hydroxides and sulphides followed by crossflow microfiltration (CMF) as a posttreatment, has been developed. The experiments were carried out on a pilot plant scale with actual wastewater from a FGD plant downstream of a coal-fired boiler. Two different types of membranes, a hydrophobic and a hydrophilic crossflow microfiltration membrane, were tested and compared with each other. The effect of membrane fouling as a function of fluid velocity and backwashing was investigated. Besides, the heavy metal concentration and the amount of suspended solids were determined before and after the CMF pilot plant. Finally, a simple and highly effective chemical cleaning method was developed.

Hopper Stops Messy Lime Spills, Saves Cleanup Time

The water treatment plant in Minot, North Dakota, uses an underground auger‐elevator system to transfer pebble lime to the storage tanks. When lime haulers unload lime at the plant, they back their hopper bottom trailers over the auger opening, and then place the slide gate over the opening, which is used to control feed rate. The lime is then dumped on the ground over the opening. When the unloading of the lime is complete, the lime remaining on the ground is shoveled up. If it rains, snows, or is windy, a considerable mess is left behind. The lime hopper described here improves conditions for lime haulers and operators. By reducing the amount of wasted lime, there is less wet lime to be thrown away and less lime dust blowing around on windy days. In addition, the lime hopper makes it easier to control the feed rate going into the auger. The article discusses material and construction of the lime hopper.

Biological Denitrification of Waste Water from Wet Lime–Gypsum Flue Gas Desulphurization Plants

Waste water from flue gas desulphurization by the wet lime-gypsum process is characterized by high contents of nitrate (150–300 mg/l N) and chloride (10–30 g/l Cl) and high temperature (40–50°C). Continuous and batch experiments with biological denitrification were performed with suspended cultures in lab-scale reactors fed with synthetic waste water with chloride concentrations up to 30 g/l Cl. Process temperatures in the range of 30–50°C were investigated. Acetate was added as carbon source. The results of the experiments show that biological denitrification was feasible at the extreme environmental conditions prevailing in wet lime–gypsum flue gas desulphurization waste water. Stable continuous denitrification was performed at chloride concentrations up to 30 g/l and at temperatures up to 45°C. A temperature optimum of 40°C was found for nitrate removal. At 50°C the denitrification had ceased in the reactors. In batch experiments an increased tendency to intermediate nitrite accumulation at increased temperatures and increased chloride levels was observed. This indicates that efforts should be made to equal out load variations in high chloride and high temperature biological denitrification in order to avoid periodical nitrite accumulation.

Treatment of Waste Water from Wet Lime (Stone) Flue Gas Desulfurization Plants with Aid of Crossflow Microfiltration

Abstract A treatment method has been developed to remove heavy metals such as As, Cd, Cr, Cu, Hg, Ni, Pb, Se and Zn very efficiently from waste water from wet lime(stone)-gypsum flue gas desulfurization plants (FGD). This method has been based on coprecipitation of heavy metal hydroxides and sulfides followed by crossflow microfiltration as a post-treatment. The experiments were carried out on pilot plant scale with actual waste water from a FGD plant downstream of a coal fired boiler. The effect of membrane fouling as a function of several process parameters was investigated. From SEM-EDS analysis it was found that the fouling layer on the membrane surface mainly consists of Mg-, Al-, Si-, Fe-compounds and gypsum. Membrane fouling could be decreased by periodical backwashing and by increasing the liquid velocity in the membranes. Moreover, a computer controlled start up procedure of the crossflow microfiltration unit was developed to minimize the effect of membrane fouling and to increase the operating t...

Heavy metal removal from waste water from wet lime(stone)—gypsum flue gas desulfurization plants

Waste water from wet lime(stone) gypsum flue gas desulfurization processes for coal-fired boilers contains suspended solids (gypsum, silica, hydroxides of iron and aluminum) and soluble salts (chlorides and sulfates of calcium, sodium and magnesium). Furthermore, small amounts of heavy metals such as As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se and Zn are present in these waste water streams. A treatment method has been developed to remove these heavy metals very efficiently. This method has been based on coprecipitation of metal hydroxides and sulfides. The hydroxide and sulfide precipitates are removed by a coagulation/flocculation technique followed by gravity settling. The coprecipitation can be carried out with sodium hydroxide or with lime. Both cases were investigated in two different pilot plants with synthetically composed waste water and with actual waste water from three different types of wet lime(stone)—gypsum flue gas desulfurization plants (lime—gypsum FGD plants without a prescrubber, one using seawater and another using river water as process water; a limestone—gypsum FGD plant with a prescrubber using river water as process water).

The Importance of Maintenance for Lime Flue Gas Desulfurization Systems

The successful, reliable operation of a power plant flue gas desulfurization (FGD) system depends largely on a good program of maintenance. Identifying the FGD equipment that is most critical to an FGD system’s overall reliability or its ability to meet emission regulations plays an important role in determining the extent of a maintenance program for a particular site. FGD maintenance programs vary considerably, depending on site-specific requirements and the support of plant owners. Many owners are reluctant to spend money on FGD maintenance because an FGD system is a nonproductive part of a power plant; however, a good maintenance program can result in longer equipment life, improved equipment performance, increased system availability, better safety, and lower operating costs. This paper uses wet and dry lime FGD systems to illustrate the advantages of good maintenance and the consequences of poor maintenance. Examples of specific tasks for preventive, scheduled, planned, and emergency maintenance are...