Briquetting Conditions Research Articles

The amenability of some Witbank bituminous ultra fine coals to binderless briquetting

Five ultra fine bituminous coals from the Witbank coalfield were studied. Selected chemical and physical properties, coal petrographic characteristics and mineralogical compositions of the coals were measured. The coals were compacted, using a briquetting press, at various feed moisture contents. The formed briquettes were then tested for compressive strength and water resistance and the values correlated with the coal characteristics and the briquetting conditions. The coals were found to be amenable to conventional binderless briquetting. The bonding in the briquettes was found to be due mainly due to the impurities in the coals, particularly kaolinite. This may add a new perspective to the fundamentals of the binderless briquetting of bituminous coals.

Briquetting of Afşin-Elbistan Lignite

In this study, low-quality Afşin-Elbistan lignite was mixed with a high-quality Siberian bituminous coal and optimum briquetting conditions were investigated for blends with and without binder materials. The blends of lignite and bituminous coal were prepared to contain 30, 40, and 50% bituminous coal and briquetted under pressures of 566 MPa and 708 MPa. The blends of lignite and bituminous coal were also briquetted using sunflower shell, sawdust and molasses as additives. In these experiments, the percentage of the lignite in the blends was fixed at 50%, so that the sum of the percentages of the bituminous coal and binder additive was always 50%. In this way, the low-grade lignite and high-quality bituminous coal dust are converted into a compact and stable fuel which has a higher quality.

Briquetting peat and peat-coal mixtures

This work shows that dried peat from the Ohinewai deposits of the Waikato River Valley region of New Zealand can be successfully briquetted without using a binder. It also evaluates this peat as a binder for the briquetting of surplus sub-bituminous coal fines from the nearby Waikato coalfield. Initially a laboratory scale press and die were used to produce briquettes of peat and various peat/coal mixtures. The physical properties and water resistance of the briquettes were analysed in relation to the varying briquetting parameters including moisture content, coal fraction and temperature. Extremely high quality briquettes were produced from pure peat and peat-coal mixtures containing up to about 50% coal, after which strength properties became marginal. The laboratory findings were applied to pilot extrusion trials by using a woodwaste briquetting press. Excellent “firelogs” were produced in several short runs, but owing to a lack of dried peat no attempt was made to optimise briquetting conditions for this machine. Insufficient “firelogs” were produced to carry out meaningful combustion tests. The immediate success achieved in these limited trials suggests that this method of agglomerating peat should not pose too many technical difficulties if taken to commercial production and that the prospect of using peat as a briquetting binder deserves due consideration.

Production of metallurgical cokes from some Turkish lignites using sulphite liquor binders

Soma and Tunçbilek lignites were briquetted at 80 °C under 0–100 MPa, using varying amounts of sulphite liquor binders. The briquettes were then carbonized at 950 °C, and the resulting formed cokes were examined. The effects of the type and concentration of binders, and of the briquetting pressure, on the strength and porosity of the formcokes were investigated. As a result of these experiments, optimal briquetting conditions were established. It was also stated that formcokes made from both Turkish lignite samples under optimal briquetting conditions could be used for metallurgical purposes, particularly in non-ferrous metallurgy.

Study on the Characteristics of Formed Coke (I)

We have studied the following three problems in order to develope the continuous formed coke process.(1) Investigation of formed coke process conducted through the world.(2) Comparison of characteristics of various kinds of formed coke.(3) Study on size of formed coke.As the results, we have recognized the following three points.(1) Studies on formed coke are putting in operation through the world, but have not been successed yet.(2) Formed cokes made in various countries generally are superior in impact strength at room temperature but are high in their reactivity to CO2 which means that they tend to affect degradation at high temperature. We considered that an effective methods of improving the reactivity are systematic studies of the heating pattern and gas atomosphere conditions during carbonization, briquetting conditions and blending ratis of raw briquette etc.(3) We estimated that desired size of formed coke are 60-63cc by the results of calculation and experimental model.

Manufacture of Briquette Coke for Blast Furnace, Using the Poorly Caking Japanese Coal as Main Raw Materials(II)

In the previous report, it was clarified that the qualities of coke im-proved, owing to elevation of coking properties of coal during carbonization from a view point of coke manufacture and physical changes in coking process by briquetting low-or non-caking coal, as compared with non-briquetting.In this study, the author investigated the relation between briquetting pressure and the space of coal particles and moreover relative relations among briquetting conditions, the amount of α-picoline extracts of coal and characteristics of α-picoline extracts.From these results, coking mechanism of briquette coal has become clear.