مصنع لتجهيز البوكسيت/coal pyrolysis process
The coalbased pyrolysis process faces so many challenges based on the production and consumption and also the limited resources, low efficiency and higher emissions. Biological origin. There has been a lot of studies on the feedstocks of biological origin used in microwave pyrolysis. Biological origin here refers to the feedstock having a ...
Pyrolysis polygeneration technology is a good way to realize clean and efficient utilization of lowrank coal and heat carrier is a key factor. Aspen Plus is used to establish lowrank coal pyrolysis staged conversion polygeneration technology with semicoke heat carrier based on dualfluidized bed (CPSCPCDFB), which couples with ultrasupercritical semicoke powder furnace for power generation.
The effect of coal rank, heating rate, and temperature on the coal pyrolysis process were discussed in this work. The initial pyrolysis pathways of different ranks of coals have been obtained, and the variation of hydrogen and carbon monoxide yield with temperature was also discussed. Fortunately, we have reached some important conclusions:
The pyrolysis process of low rank coal is the initial reaction of reductant source in the coalbased reduction process, and the volatiles of the gas pyrolysis product such as H 2 has a significant effect on the subsequent reduction process of iron oxides, which is an ideal reductant for reduction of iron ore.
(1), where m 0, m t were the initial mass of coal and the mass at a given time during the pyrolysis process, respectively. And m ∞ was the final mass of coal sample when the pyrolysis process was completed. (1) α = m 0m t m 0m ∞. The heating rate β was defined as Eq. (2). (2) β = d T d t
Coal pyrolysis is a process of multistage transformation using the composition and structural characteristics of coal to replace oil and gas resources (Qu et al., Citation 2010). In the process of coal pyrolysis, the pyrolysis gas is doped with particulate coal owing to combustion insufficiently. The filtration system is part of the coal ...
Pyrolysis, which is the initial stage of the coal conversion process, is a significant approach to realize efficient coal resource utilization. Current research on the mechanism of the coal pyrolysis reaction primarily focuses on aspects such as the generation law of pyrolysis products [6], evolution characteristics of the chemical structure ...
Coal pyrolysis refers to a series of physical and chemical changes that occur when coal is heated under an isolated atmosphere or inert atmosphere. The organic matter in coal can be pyrolyzed to produce char, tar, and gas. The chemical process of coal pyrolysis is very complicated, mainly involving bond breaking, vaporization, and polyreaction.
Abstract. The thermal effects of five coal types' pyrolysis processes at heating rates of 5, 10, 15, 20, and 30 °C/min in the temperature range of 301000 °C were systemically investigated by thermogravimetric differential scanning calorimetry degassing stage S2, the pyrolysis stage S3, and the polycondensation stage S4.
The thermal effects of five coal types' pyrolysis processes at heating rates of 5, 10, 15, 20, and 30 °C/min in the temperature range of 301000 °C were systemically investigated by thermogravimetric differential scanning experimental results show that coal pyrolysis process can be roughly divided into four stages, namely the drying and dehydration stage S1, the degassing ...
For the coal pyrolysis process, unstable sulfur compounds will decompose, generate sulfur radicals and release as sulfurcontaining gases, this becomes the main pathway for sulfur removal. Coal properties, minerals and sulfur forms in coal, and pyrolysis conditions such as temperature, atmosphere, and the mass transfer, are the main factors ...
As a comprehensive description of the functional groups effect on various volatile products during coal pyrolysis process, it is found that both alkyl and oxygencontaining groups can reduce the BDEs of the bridge bonds between aromatic rings during pyrolysis process, and the effect of oxygencontaining groups is more obvious. ...
The pyrolysis process consists of a very complex set of reactions involving the formation of radicals. The overall decomposition of coal is open to manipulation by a variety of experimental conditions. Due to the nature of the coal conversion processes distinction should be made between slow Cheating rate < 1 K/s) and rapid Cheating rate > 1000 ...
The complexity of coal combustion has made more researchers divide the combustion process into two stages: pyrolysis and late combustion. Up to now, many studies have been done on transformation behavior of nitrogen during coal pyrolysis [16], [17] and occurrence state and content of nitrogen in coal [18] .
When the temperature exceeds 3250 K, the pyrolysis reaction was completed and the yield of each product stabilizes. The lower heating rate completely reproduces the pyrolysis process of coal, and the pyrolysis stages obtained by simulation are close to Fugu subbituminous coal [57]. At 10 K/ps, the content of char is the least and Ltar is the ...
In this study, coal fly ash was functionalized, using a simple onestep process (loading with Al3+ and sulfonation), to yield a solid acid catalyst (S/AlCFA) with strong acid sites. The catalyst was then used to produce furfural from xylose in a biphasic system (H2O(NaCl)/tetrahydrofuran). The furfural yield reached 82% at 180 °C60 min with catalyst/xylose ratio of : (w/w).
The pyrolysis of coal is a good method for producing liquid fuels and other chemicals; however, the yields of these products are limited due to low content of hydrogen in coal. Hydropyrolysis, a pyrolysis process under hydrogen, is an effective method to improve tar yield and quality, but high cost of pure hydrogen hinders its industrial ...
In order to further reveal the thermochemical reaction characteristics in the pyrolysis process, the changes of chemical structures of coal during the coking process from room temperature to 520 °C was studied through insitu FTIR, and the results are shown in Figure 5. There are a lot of aromatic structures in the four coking coals, and the ...
The whole treatment process of CPW is shown in Fig. 1. The coal particles are introduced into the drying unit to provide steam for CLG and the remaining dry coal enters into the pyrolysis unit to produce pyrolysis gas and char. The CPW is generated during cooling and separation of pyrolysis gas. The dotted red line represents the impact of CPW ...
The coal samples were pulverized, grounded and sieved to a particle size of less than 75 μm before storing in a desiccator for use. The property analyses of the coals were shown in Table 1. TGA and TGMS experiments. Pyrolysis of the coals was conducted with a TG (50H, Shimadzu, Japan). In. Characterization of coals