At pH =1, very little separation efficiency almost 26% of sulfur removal, and 16% of ash removal were recorded, then with the increase of pH value with respect to time, its value increases reaches ...
A process for reducing the sulfur and ash content of coal wherein coal particles are treated in an aqueous slurry with a minor amount of hydrocarbon oil to form coal-oil aggregates. The coal-oil aggregates are separated from ash and mineral matter in the slurry by dissolved gas flotation. Optionally, the coal particles may be treated with a …
To uncouple the complex behavior of sulfur transformation during thermal processing of coal and to elucidate the main mechanism, typical organic and inorganic sulfur compounds impregnated on or mixed with a low-ash char are studied through temperature-programmed decomposi tion coupled with online mass spectrum analysis …
Most coal requires some preparation before use. Preparation may range from simply crushing to provide a size consist suitable for certain types of boilers to extensive size …
Molten caustic leaching process is effective in reducing significant amount of ash derived from minerals, pyritic sulfur, and organic sulfur from coal. The effect of leaching coal samples from Hazro fields, situated in Southeast Anatolia region of
In addition, there will be a small amount of elemental sulfur in the coal, PbS, CuFeS2, FeAsS, and ZnS [6,7,8]. Among them, the inorganic sulfur in coal is easier to remove than organic sulfur, and the high sulfur coal in China is generally pyrite, which has a good correlation with ash.
most promising method to effectively remove all sulfur forms. Acids and alkaline solutions can be used sequen-tially and in various mixtures to produce coal with both low ash and low sulfur. Some commercial ash-free coal meth-ods requiring heated oil as solvent may exist, but the process is not economically feasible. Most of these
Molten caustic leaching process is effective in reducing significant amount of ash derived from minerals, pyritic sulfur, and organic sulfur from coal.
The throughput of high-ash and high-sulfur fine-grain coal (0–6 mm) increases year by year. The serious problem of direct combustion is the formation of acid rain and smog.
The percentage of demineralization and desulfurization increased with the increase in alkali/coal ratio. The removal of total sulfur and ash increases with increasing leaching temperature and time. As a result of MCL, ash content of Hazro coal was reduced from 18.31 to 6.77 %, and 70% of combustible was recovered.
According to Duz et al. treated the coal with a solution of NaOH and followed by acid at the temperature of 400˚C for 45 minutes, inorganic & 70% of organic sulfur and ash contents were ...
Removal of sulfur and ash from coal using molten caustic leaching, a case study from Hazro fields, Turkey M. Zahir Duz1, Abdurrahman Saydut2'*, Sait Erdogan1 and Candan Hamamci1 ... compounds ashes, and hazardous trace elements, the use and the processing of coal could cause environmental, industrial and technological problems. …
Molten caustic leaching process is effective in reducing significant amount of ash derived from minerals, pyritic sulfur, and organic sulfur from coal.
Most coal requires some preparation before use. Preparation may range from simply crushing to provide a size consist suitable for certain types of boilers to extensive size reduction and cleaning to remove sulfur and ash-forming mineral matter. At …
A low-rank coal cleaned by heavy-liquids separation was treated by 1 M KOH solution at room conditions for a maximum of 2 h. The desulfurization mechanism in terms of total sulfur was well ...
The process of sulfur removal by microbes is carried out by enzymes and is considerably influenced by different factors including pH, temperature, nutrient composition, shaking or standing ...
Processing coal. After removing the coal from the ground, miners may send it to a preparation plant near the mining site. The plant cleans and processes coal to remove rocks, dirt, ash, sulfur, and other unwanted materials. This process increases the heating value of the coal. Transporting coal
One such classic study monitored improvements to boiler performance resulting from switching from an untreated coal (15% ash and 3.5% sulfur) to washed coal (9% ash and 2.8% sulfur) from the same mine. Despite the modest improvement in coal quality, the boiler efficiency increased from by about 1.5 absolute percentage points as a result …
Sulfite removal from high-sulfur coal fly ash is rapid and selective in acidic pH. Acid generated from oxidation of dissolved sulfite can be gainfully recycled. Sulfuric …
Therefore, removal of mineral matter and sulfur from coal prior to its utilization is necessary [2]. Many researchers have tried to find an economically practical process for removing sulfur from coal, but no such process has been developed yet [3]. The chemistry of sulfur is so complex that it greatly complicates the removal of sulfur …
Removal of SO2 from flue gas by the absorbent prepared from coal fly ash, calcium oxide, and calcium sulfate was studied under different reaction conditions to elucidate the effects of the reaction temperature, water vapor pressure, and coexistence of NO in a flue gas. The SO2 removal activity increased with an increase in NO …
3.. Results and discussionThe desulfurization experiments were carried out at 400–650 °C using the simulated coal gas which contains 0.47 vol% H 2 S. In blank experiments during which the simulated coal gas passed through the hot U-shape quartz reactor without a sorbent bed, about 500 ppm COS was detected in the outlet gas …
To remove coal in these underground mines, miners ride elevators down deep mine shafts where they run machines that dig out the coal. Processing the Coal Source: bloomberg. After coal comes out of the ground, it typically goes on a conveyor belt to a preparation plant that is located at the mining site. The plant cleans and …
The process effectively removed over 95 percent of the pyritic sulfur in the coal. Reclamation of pyritic sulfur would eliminate stream pollution by acid water …
High-sulfur mixed fly ash residues from semi-dry flue gas desulfurization units in coal-fired power plants are unsuitable for use as supplementary cementitious material (SCM) for concrete production or carbon dioxide utilization. In this work, we explore the potential for upcycling a representative spray dry absorber ash (10.44 wt% SO 3) …
Mild alkali treatment for relatively short period leads to removal of ash from the coal samples. Increase of alkali concentration and treatment time has negative …
Some high sulfur coals were extracted with an aqueous alkaline solution obtained from the water soluble fraction of different wood ashes. By this method, high sulfur removal from lignites was possible. The effects of temperature, amount of wood ash used, partial pressure of oxygen, extraction time and stirring speed were studied in the …
This study describes the desulphurization process of coal using an aqueous solution of cupric ions as an oxidant. Complete sulphur removal from coal was …
Because there are some alkali and alkaline earth compounds in coal ash, it is feasible to make use of them to prepare low-cost sorbents for sulfur removal. The key problem is to activate the effective compositions in coal ash, generally by a hydration process of Ca(OH) 2 and coal ash under elevated pressure. Hydration promotes the …
As one of the dangerous trace elements in coal, mercury has become an advanced research hotspot in coal purification. The content of ash, sulfur, and mercury of raw coals from four high-Hg coal preparation plants located in the main production areas of China was tested. To distinguish the connection between mercury content and the …
Molten caustic leaching process is effective in reducing significant amount of ash derived from minerals, pyritic sulfur, and organic sulfur from coal. The effect of leaching coal samples from Hazro fields, situated in Southeast Anatolia region of Turkey with molten sodium hydroxide as well as followed by mild acid on demineralization and …
The effects of process variables on coal yield, as well as on ash reduction and total sulfur reduction, have been analyzed using analysis of variance. Among the …
The combined effect of desulfurization and ash removal in the process of coal desulfurization by microwave with peroxyacetic acid was determined by evaluating variations in minerals and sulfur forms using X-ray diffraction and X-ray photoelectron spectroscopy. Dielectric properties of minerals or organic sulfur functional groups in …
The combined effect of desulfurization and ash removal in the process of coal desulfurization by microwave with peroxyacetic acid was determined by evaluating variations in minerals and sulfur ...
Transport reactor gasifier of KBR is a recent development, which is mid-way between fluidized and entrained bed gasifier. It can simultaneously remove sulfur and may be the better option for gasification of Indian coals. Fluidized bed gasifier may also be considered for the gasification of Indian coal containing high ash and low sulfur.
Learn how coal cleaning removes impurities such as sulfur, ash, and rock from coal to upgrade its value. Find out the types, sources, and controls of emissions from coal …