煤气化过程中焦油裂解的试验研究

煤在热解和气化过程中产生的焦油，影响系统的正常运行。焦油脱除方法可分为气化炉内(初次脱除)和气化炉外(二次脱除)两类。尽管二次脱除法非常有效，但由于气化炉内初次脱除可以大大减少出口煤气中焦油含量，减轻甚至消除后期处理焦油的压力，故气化炉内脱除法得到重视。采用石灰石为催化剂，在1MW热态试验台上进行了试验，研究焦油和煤气成分在空气气化时添加不同石灰石含量工况下的变化情况，结果表明，石灰石的加入降低了焦油产率，提高了煤气产率，改善了煤气质量。     

The zinc chloride process for the hydrocracking of coal

The molten zinc chloride process is a unique hydrocracking system that converts coal to gasoline in a single step. an economically attractive process is currently under development at the one ton per day process development unit (PDU) scale. the design and economics of a plant to produce 53,000 bbl/day of gasoline with 90–92 unleaded research octane number from Western coal is discussed. the construction cost of the plant will be about 1.9 billion dollars (1979); the cost of manufacturing gasoline is about 76c/ gallon (20c/litre).     

An experimental study of the effect of water content on combustion of coal tar/water emulsion droplets

Isolated high asphaltene droplets of coal tar/water emulsion were studied to investigate the non-steady behavior of the burning droplets. Data on size and temperature histories were obtained. Coke residues were analyzed by scanning electron microscope. Lower and upper limits for ignition time delay were established. The error, defined as the time lag between these two limits, was less than 8 ms. Ignition time delays of emulsions were longer than for ordinary coal tar (CT) droplets of the same size but the peak temperature of emulsions occurred much earlier. A steeper temperature rise observed in the emulsions during portions of their combustion history is evidence not only of soot reduction but also the extent of burnout of the cenospheres. The latter is an important aspect in the reduction of pollutant emissions. The emulsion droplets indicated swelling of considerable magnitude compared with that of CT. Coke particles formed from emulsions were more porous, with thinner and fragile shells. The CT residues were harder and more resistant to burning. Excess burnout time or the ratio of burnout time of the emulsions depended on the water concentration, indicating that longer oxidation time was required for coke particles from coal tar than from emulsions.     

Fuel oil production through high-temperature coal tar catalytic hydrocracking in supercritical xylene

The paper aimed to build a model for high-temperature coal tar (HTCT) catalytic hydrocracking in supercritical xylene with the conceptual design of energy self-sustainability based on Aspen Plus. The following tasks were done to boost the reliability of the model: selecting reasonable model compounds for HTCT, using pseudo-components to describe the nature of products and choosing reliable property methods for blocks. Results showed products can be well separated by the block rectifying column (DIST); additionally, the total heat recovery was as high as 2,355 kW h, among which 1,434 kW h was from the heat carried in the outlet stream of REACTOR. The total energy consumed by the energy consumption equipments was 882.5 kW h.     

Structural features of Qitaihe high-temperature coal tar by sequentially fractional extraction

A coal tar was sequentially extracted with petroleum ether, methanol, butanone, carbon disulfide, and isometric butanone/carbon disulfide mixed solvent to afford extracts 1 to 5 (E₁ to E₅) under ultrasonic irradiation in a batch extraction system, respectively. All of the extracts were analyzed with Fourier transform infrared and gas chromatography/mass spectrometer. Results showed that 18 compounds were detected in E₁, including 17 condensed arenes varying from one to five rings and 1 organooxygen compound. A series of heteroatom-containing organic species were enriched to large extents in E₂; and 16 compounds were detected in E₃, including 13 condensed arenes, 1 organosulfur compound, and 2 organonitrogen compounds. Organic species in E₄ and E₅ with molecular weight beyond the measurement range of gas chromatography/mass spectrometer were identified using Fourier transform infrared. Possible structures of some highly condensed aromatic species were inferred.     

Investigation on the structure of low-temperature coal tar asphaltene precipitated with different n-alkane solvents

To study the effects of deasphalting solvents on asphaltene, n-pentane asphaltene (As-5), n-heptane asphaltene (As-7), and soluble in n-heptane but insoluble in n-pentane asphaltene (As-(5–7)) were precipitated from low-temperature coal tar. Gel Permeation Chromatography (GPC), nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to analyze their structure. The results show that As-(5–7) is composed of the aromatic layer periphery of As-5, so the aromatic degree of As-(5–7) is lower and the content of alkyl and naphthenic base groups is larger. What is more, the aromatic ring consistency and condensation degree of As-(5–7), As-5, and As-7 increase gradually, so their coking potential and hydrogenating difficulty increase.     

Research on the combustion characteristics of anthracite and blended coal with composite catalysts

Composite catalysts composed of different proportion of chemical reagents and steel industrial wastes were used as coal-burning additives. The effects of additives on combustion characteristics of anthracite coal and blended coal were studied by thermogravimetric analysis (TGA). The results showed that appropriate amount and proportion between chemical reagents and waste slag used as composite catalysts had good performances on the characteristics of coal combustion including ignition temperature, burnout temperature and burnout index, this will improve the coal combustion efficiency and also facilitate the comprehensive utilization of steel industrial waste slag.     

Application of mathematical model for the process of coal tar pitch modified petroleum asphalt

This paper firstly discusses the properties of modified asphalt by blending petroleum asphalt and coal tar pitch. Then, a new mathematical model which was called ZQL was constructed. Based on three variables, property, granularity size, and proportion, the three-dimension function was fit, where the property was set as a dependent variable and the rest of the variables were set as independent variables. The different functions were finally obtained. Finally, based on the British standard of road asphalt, we solve the ZQL model and obtain a suitable result which matches the experimental results very well.     

Experimental comparison of biochar species on in-situ biomass tar H2O reforming over biochar

Experimental investigations of in-situ tar H₂O reforming over various biochar species were carried out in the two-stage fluidized bed/fixed bed reactor. The physicochemical structures of biochar were studied by SEM, mercury intrusion porosimetry and FTIR methods. The mechanism of tar H₂O reforming over biochar was studied through the results of tar yields and quantitative analysis of typical tars by GC/MS. According to the theory of organic mass spectrometry and current mechanisms of tar transformation, the reaction path of typical tar H₂O reforming over biochar was constructed. The results show that the tar reforming rate over sawdust biochar is the most significant among the three kinds of biochar samples (i.e., rice husk, sawdust and cornstalk). The metallic species contribute greatly to the weight loss of biochar in 15 vol% H₂O atmosphere at 800 °C, while they are not the only determinants of tar H₂O reforming. The selectivity of biochar on the in-situ tar H₂O reforming is determined by the coupling effects of its physical and chemical characteristics. The biochar, with the porous surface structures, a certain amount of metallic species and the carbon structure with low polymerization, would be effective on in-situ tar H₂O reforming.     

农作物秸秆类生物质焦油燃料利用特性的实验研究

主要对农作物秸杆类生物质热裂解焦油的馏程，发热量，粘度，闪点，碳氢元素的质量分数等动力燃料利用特性进行了实验研究。研究结果表明，农作物秸杆类生物质热裂解焦油的轻质馏出物具有适当的蒸发性，良好的燃烧性和高度的安全性，符合发动机对液体燃料的质量要求，可以作为发动机的代用动力燃料，而重质馏出物可进一步加工制造生物质焦油抗聚剂，生物质焦油抗氧剂，工业杂酚药用生物质焦油和生物质沥青增塑剂等。     

Study on steam reforming of coal tar over NiCo/ceramic foam catalyst for hydrogen production: Effect of Ni/Co ratio

The effect of Ni/Co ratio on the catalytic performance of NiCo/ceramic foam catalyst for hydrogen production by steam reforming of real coal tar was studied. The NiCo/ceramic foam catalyst was synthesized by deposition-precipitation (DP) method and characterized with different methods. The experiments were conducted in a two-stage fixed-bed reactor. The results showed that the reducibility of the metallic oxides in bimetallic NiCo/ceramic foam catalysts was influenced obviously by the Ni/Co ratio.Both gas and hydrogen yield increased first and then decreased with the decline of Ni/Co ratio, and the highest hydrogen yield of 31.46 mmol g^?1 was obtained when the Ni/Co ratio was 5/5. The lowest coke deposition of 0.34 wt% was generated at the same Ni/Co ratio. The lifetime test showed the catalyst maintained catalytic activity after 14 cycles (28 h), indicating the coal tar steam reforming on NiCo/ceramic foam catalyst is a promising method for hydrogen production.     

Preparation of high-activity coal char-based catalysts from high metals containing coal gangue and lignite for catalytic decomposition of biomass tar

The potential of using high metals containing coal gangue and lignite to prepare high-activity coal char-based catalysts is investigated for effective biomass tar decomposition. Loose structure and rough surface are formed for these char-based catalysts with heterogeneous distribution of a large number of inorganic particles. In the biomass tar decomposition, the performance of the coal char-based catalysts is significantly influenced by the content of the metals in the raw materials and coal gangue char (GC) with the ash content as high as 50.80% exhibits the highest activity in this work. A high biomass tar conversion efficiency of 93.5% is achieved at 800 °C along with a significant increase in the fuel gas product. During the five-time consecutive tests, the catalytic performance of GC increases a little at the second or third times reuse and remains relatively stable, showing the remarkable stability of the catalyst in biomass tar decomposition applications.     

Experimental study on influence of operating parameters on tar components from corn straw gasification in fluidized bed

Gasification is a promising approach for converting solid fuel sources, including renewable ones like biomass, for use. The main problem in biomass gasification is the formation of condensable tars, including polycyclic aromatic hydrocarbons (PAHs). This paper investigated the conversion of tar components during corn straw gasification. It analyzed collected tar components using a gas chromatograph-mass spectrograph (GC-MS). Experimental results indicate that, with increasing temperature from 700°C to 900°C, the concentrations of benzene, indene, phenanthrene, naphthalene, acenaphthylene, fluorene, and pyrene increased whereas those of toluene, phenol, 1-methylnaphthalene, and 2-methylnaphthalene decreased. As the equivalence ratio (ER) increased from 0.21 to 0.34, the concentrations of indene and phenanthrene increased from 0.148% and 0.087% to 0.232% and 0.223%, respectively. Further, the phenol content increased as ER increased from 0.21 to 0.26 and then decreased as the ER increased further to 0.34. Other parameters like the steam/biomass (S/B) ratio and catalyst also played a critical role in tar reduction. This paper demonstrates the conversion of some tar components and elucidates their chemical properties during gasification.     

Experimental study on coal multi-generation in dual fluidized beds

An atmospheric test system of dual fluidized beds for coal multi-generation was built.One bubbling fluidized bedis for gasification and a circulating fluidized bed for combustion.The two beds are combined with two valves:one valve to send high temperature ash from combustion bed to the gasification bed and another valve to sendchar and ash from gasification bed to combustion bed.Experiments on Shenhua coal multi-generation were madeat temperatures from 1112 K to 1191 K in the dual fluidized beds.The temperatures of the combustor are stableand the char combustion efficiency is about 98%.Increasing air/coal ratio to the fluidized bed leads to theincrease of temperature and gasification efficiency.The maximum gasification efficiency is 36.7% and thecalorific value of fuel gas is 10.7 MJ/Nm3.The tar yield in this work is 1.5%,much lower than that of pyrolysis.Carbon conversion efficiency to fuel gas and flue gas is about 90%.     

High energy density capacitor using coal tar pitch derived nanoporous carbon/MnO2 electrodes in aqueous electrolytes

Asymmetric aqueous electrochemical capacitors with energy densities as high as 22 Wh kg⁻¹, power densities of 11 kW kg⁻¹ and a cell voltage of 2 V were fabricated using cost effective, high surface carbon derived from coal tar pitch and manganese dioxide. The narrow pore size distribution of the activated carbon (mean pore size ∼0.8 nm) resulted in strong electroadsorption of protons making them suitable for use as negative electrodes. Amorphous manganese dioxide anodes were synthesized by chemical precipitation method with high specific capacitance (300 F g⁻¹) in aqueous electrolytes containing bivalent cations. The fabricated capacitors demonstrated excellent cyclability with no signs of capacitance fading even after 1000 cycles.     

Optimization of hydrogen production from steam reforming of biomass tar over Ni/dolomite/La2O3 catalysts

Industrially, the endothermic process of steam reforming is carried out at the lowest temperature, steam to carbon (S/C) ratio, and gas hourly space velocity (GHSV) for maximum hydrogen (H₂) production. In this study, a three-level three factorial Box-Behnken Design (BBD) of Response Surface Methodology (RSM) was applied to investigate the optimization of H₂ production from steam reforming of gasified biomass tar over Ni/dolomite/La₂O₃ (NiDLa) catalysts. Consequently, reduced quadratic regression models were developed to fit the experimental data adequately. The effects of the independent variables (temperature, S/C ratio, and GHSV) on the responses (carbon conversion to gas and H₂ yield) were examined. The results indicated that reaction temperature was the most significant factor affecting both responses. Ultimately, the optimum conditions predicted by RSM were 775 °C, S/C molar ratio of 1.02, and GHSV of 14,648 h⁻¹, resulting in 99 mol% of carbon conversion to gas and 82 mol% of H₂ yield.     

Experimental study on the pyrolysis of Shenhua coal to produce hydrogen

Based on thermogravimetric analysis, kinetic parameters of Shenhua coal, such as activation energy and frequency factor have been got from the TG / DTG results. It showed that activation energy is the smallest at the temperature from 850℃ to 930℃ with heating rate of 15℃·min-1 . Pyrolysis was further carried out on a fixed-bed reactor with different heating rate. The production of hydrogen has been studied in particular. It gave the highest hydrogen production at the heating rate of 15℃·min-1 . And it also found the increase of hydrogen production with the raise of temperature. Furthermore, catalytic pyrolysis of coal was done at adding 2% of transition-metal oxides to discover the impact of catalysts upon coal pyrolysis at heating rate of 15℃·min-1 . It indicated that both N-type and P-type oxide enhanced hydrogen production in coal pyrolysis. However, it showed that N-type oxide increased hydrogen production at medium temperatures, and P-type oxides improved hydrogen production at higher temperatures.     

热解和气化过程焦油析出的影响因素分析

在热解和气化过程中产生的焦油给气化工业带来极大的不便。讨论了温度、停留时间、压力、气氛、拉径以及床料等对热裂解和催化裂解产生的影响。催化剂的加入对上述因素又产生了新的影响。同时介绍了不同研究者对催化剂性能的研究，在此作出对比。     

利用破乳剂对低温煤焦油进行初步脱水的研究

采用添加破乳剂的方法探究煤焦油在进行深加工前脱水效果和影响因素。实验主要就破乳剂的种类选取、搅拌时间、搅拌速率、脱水温度、破乳剂质量分数以及静置时间等各方面对脱水效果的影响进行探究,发现随搅拌速率、脱水温度、破乳剂质量分数等的提高以及搅拌时间、静置时间等的延长,水分脱除率呈现不断上升直至平稳的趋势,同时对实验结果进行了分析。在实验基础上,提出破乳脱水的工艺流程方案,目标是使焦油在一段蒸发器出来后的含水质量分数小于0.5%。     

镍基镁渣催化剂对生物质焦油模化物催化重整特性实验研究

采用湿浸渍法制备Ni/γ-Al₂O₃和Ni/MS(magnesium slag)催化剂,选择糠醛、甲苯、萘、芘作为生物质焦油的模化物,研究不同镍基催化剂对四类焦油模化物在固定床反应器内进行催化重整的重整特性。结果表明,Ni/MS催化剂在催化所有模化物的重整反应时,气相碳转化率和气体产率均明显高于Ni/γ-Al₂O₃催化剂。当水分子物质的量与碳原子物质的量之比为1.5时,糠醛的气相碳转化率达到最高值86.54%。X 射线衍射 (XRD)结果表明,Ni/MS催化剂上存在的多种固溶体（NiO-Fe₂O₃、NiO-MgO）形成了多种活性位点。