Influential factors on the oil agglomeration process for coal recovery from different grade coals

Abstract

Large amounts of waste fine coals are produced, which are difficult to be treated because of high ash content and inorganic sulfuric compounds. In order to make efficient use of waste fine coal, a retrieval technique is necessary for the recovery of coal combustible content from fine waste coals. Nowadays, the floatation process can be used, but it is impractical for developing countries due to high costs, then the oil agglomeration process can deal with these problems. In this study, we investigated the affecting factors of coal cleaning efficiency of oil agglomeration on the element content and chemical structure of three different grade coals because there are many grades of coals around the world. For determination of chemical content in three different grade coals, the help of proximate and ultimate analysis was used, and then for investigation of their chemical structure differences of carbonaceous content, a Fourier transforminfrared spectrometry (FT-IR) was applied. Furthermore, for the oil agglomeration experiments, kerosene and vegetable oil which differ in structure were used as aggregating agents. We used ash free coals or their mixed samples which were conditioned to the ratios of carbonaceous and ash content in order to make it the same contained amounts. From the results of the oil agglomeration experiments, it was concluded that the characteristics of agglomerate and the coal cleaning efficiency of oil agglomeration are not only influenced by the oil types, but also affected by the oxygenic content, aromatic and aliphatic chemical structures in different grade coals. Oxygenic function groups of carbonaceous content in coal samples ,

Flotation of weathered coal discards using a HIP W/O emulsion binder and kerosene

“…This was undertaken to determine the degree of weathering of the coal surfaces. Coal oxidation is denoted by the intensity of the oxygenated functional groups such as the hydroxyl (O-H) and carbonyl (C=O) (Wang et al, 2012). A distinct and intense peak of O-H groups is present for sample 2, suggesting that the coal is highly weathered.…”

Clarification of the reaction at the solution interface of pyrite during oil agglomeration for developing desulfurization and coal cleaning efficiency

“…In the formula, agglom and feed denotes recovered agglomeration and coal samples, respectively, and wt gives the weight unit (g). In equations ( 6)- (10), SS and PS are the contents of sulfate sulfur and pyrite sulphur, respectively, and CM is 100 -(ash content) [8,9]. R (%) = 100 × wt agglom (g) / wt feed (g) ( 5) SSR (%) = 100 × (1 -SS agglom (%) × wt agglom (g)) / (SS feed (%)× wt feed (g) ( 6) PSR (%) = 100 × (1 -PS agglom (%) × wt agglom (g)) / (PS feed (%)× wt feed (g) ( 7) CMR (%) = 100 × CM agglom (wt.%) ×wt agglom (g) / (CM feed (wt.%) × wt feed (g)) ( 8) AR (%) = 100 -100×Ash agglom (wt.%) ×wt agglom (g) / (Ash feed (wt.%) × wt feed (g)) ( 9)…”

“…In recent days influencing factors of the oil agglomeration process were investigated by experiments using different grade coal and it was concluded that aromatic and aliphatic functional groups of carbonaceous content had an important function. However, the oil agglomeration process has not been put to practical use because the coal cleaning efficiency is low and usage of recovered carbonaceous content is not discussed [7,8]. We need to accumulate the data for commercial viability of oil agglomeration in the future.…”