The effect of the initial water of lignite on its liquefaction reactivity
In this paper, the effect of different initial water content of lignite on its direct liquefaction reactivity was studied. The results show that: initial water content in lignite can be used as hydrogen supplier and promote direct liquefaction reaction inducing higher total conversion rate, higher oil yield and lower pre-asphaltene / asphaltene yield, when the water content of lignite is of 20 ~ 30%. And the maximum of total conversion rate and oil yield is achieved 85.12% and 51.72%, respectively, when the water content of lignite is 25.33%. While the gas product yield and the pre-asphaltene /asphaltene yield is relatively lower, which is of 11.16% and 3.93%, respectively. This can be of practical significance to optimize the coal pre-treatment technology of direct liquefaction industry.
A new process for catalytic liquefaction of coal using dispersed MoS2 catalyst generated in situ with added H2O
Abstract We have found that adding a proper amount of water can dramatically improve conversion of a sub-bituminous coal in solvent-free liquefaction under at 350°C using ammonium tetrathiomolybdate (ATTM) as precursor to dispersed MoS 2 catalyst H 2 pressure. However, adding water to catalytic reactions at 400°C decreased coal conversion, although water addition to the non-catalytic runs was slightly beneficial at this temperature. We further examined the effect of water in solvent-mediated runs in addition to “dry” tests and explored a temperature-programmed liquefaction (TPL) procedure to take advantage of the synergetic effect between water and dispersed Mo catalyst precursor at low temperatures for more efficient coal conversion. The TPL using ATTM with added water at 350°C, followed by water removal and subsequent reaction at 400°C gave good coal conversion and oil yield. Model reactions of dinaphthyl ether (DNE) were also carried out to clarify the effect of water. Addition of water to ATTM substantially enhanced DNE conversion at 350°C. The combination of data from one-step and two-step tests of DNE and coal at 350–400°C revealed that water results in highly active MoS 2 catalyst in situ generated at 350°C, but water does not promote the catalytic function or reaction once an active catalyst is generated. Using ATTM coupled with water addition and removal and temperature-programming may be an effective strategy for developing a better coal conversion process using dispersed catalysts.
Assessment of some agro-technological parameters of cactus pear fruit ( Opuntia ficus-indica Mill . ) in Morocco cultivars
Cactaceae had always attracted attention by their strange shapes and important adaptability supporting extreme conditions. For this reasons, Fruit traits were measured on 13 cultivars growing in different locations in Morocco. Results show significant differences between the cultivars. The source of this variation was probably genetic without excluding the geographic effects. The Tamri, Berkan, Ait Baha cultivars showed small fruit dimensions and weight. In contrast, Sidi-Ifni M, Nador, Mohammedia and Ben Guerir were greater than 100 g by fruit. Sidi-Ifni M, Hoceima, Mohammedia and Nador, although larger, contained few seeds, about 200 seeds per fruit; while Tamri, Ait Baha, Safi, Meknes and Tafraout contained over than 230 seeds per fruit. High levels of juice about 62 ml/100 g pulp were obtained with Sidi-Ifni M, Nador, Mohammedia and Ben Guerir cultivars. Total sugars of the 13 cultivars were quite similar and pH was low in Tamri and close to neutrality in the rest of cultivars. Therefore, oil extracted from Opuntia ficus-indica seeds constituted 13.6% of the whole seed. Thin-layer chromatography in conjunction with gas-liquid chromatography-mass spectrometry revealed a relatively high degree of unsaturation, 83.32% and 16% for saturated fatty acid, with a linoleic acid content of 63.66% followed by oleic 18.34%, palmitic 12.84% and stearic acid 2.81%. Based on these results, O. ficus-indica seed oil appears to be a good potential source of edible oil for human and (or) animal consumption. Our investigation describes that Tamri and Tafraout cultivars are not really a commercial viable fruit due to low total soluble solids value and highest seeds number per fruit. Against Mohammedia, Sidi Ifni M and Nador cultivars proved to have the highest fruit weight, very good total soluble solids value and low number of seeds, these cultivars can therefore be planted for both fruit production and for harvesting of cladodes for animal feed.