Rapid Hydropyrolysis Research Articles

No.21 低品位炭の急速水素化熱分解(熱分解・コークス(5)、ガス化・燃焼・液化(1))

No.21 低品位炭の急速水素化熱分解(熱分解・コークス(5)、ガス化・燃焼・液化(1))

1-3-2 石炭、廃プラスチック、バイオマスの急速水素化熱分解による燃料製造(1-3 熱分解・石炭改質,Session 1 石炭・重質油等,研究発表)

1-3-2 石炭、廃プラスチック、バイオマスの急速水素化熱分解による燃料製造(1-3 熱分解・石炭改質,Session 1 石炭・重質油等,研究発表)

Rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar

The rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar was carried out in a hydrogen atmosphere at 1073 K and 973 K. The assumed oligomers were partially pyrolyzed epoxy resin with biomass tar as solvent for the resin. The product distributions obtained from rapid hydropyrolysis of phenol and bisphenol-A are shown. We also discuss the effects of reaction temperature and hydrogen partial pressure on the product yield. In particular, more phenol was produced from bisphenol-A at 973 K than at 1073 K. The yield of methane, which was the final hydropyrolysis product, increased with increasing hydrogen partial pressure, whereas benzene and phenol were believed to behave as intermediate products in the hydropyrolysis reaction. The results suggest that phenol could be obtained with high selectivity from tar by optimizing the reaction conditions.

03/01615 Sulfur transformation during rapid hydropyrolysis of coal under high pressure by using a continuous free fall pyrolyser: Xu, W.-C. and Kumagai, M. Fuel, 2003, 82, (3), 245–254

03/01615 Sulfur transformation during rapid hydropyrolysis of coal under high pressure by using a continuous free fall pyrolyser: Xu, W.-C. and Kumagai, M. Fuel, 2003, 82, (3), 245–254

Gasification of coals in high-temperature shaft furnaces : Volovik, A. V. et al. Ekologiya i Promyshlennost Rossii, 2002, 37–38. (In Russian)

Seven bituminous and sub-bituminous coals were rapidly hydrodesulphurized with a free-fall pyrolyser at atmospheric pressure, temperatures up to 1233 K and a heating rate of ≈ 6000 K s−1. The observed changes in the contents of sulphur forms were successfully simulated kinetically. Organic sulphur content was reduced by 54–92% and pyritic sulphur was almost reduced to ferrous sulphide sulphur in a very short reaction time of < 0.5 s. The release rate of volatile organic sulphur to tar and gas increased with increasing release rate of volatile matter and with increasing internal surface area. As the release rate of volatile matter changed from 8 to 43 s−1 with the increasing ratio of internal surface area of 1–4, the frequency factor of the release rate of volatile organic sulphur to tar and gas increased from 1.1 × 105 to 3.4 × 105 s−1 and that of organic sulphur to tar increased linearly from 3 × 104 s−1 to 2 × 105 s−1. The desulphurization results of total sulphur and char yield in rapid hydropyrolysis at atmospheric pressure and those in slow heating hydropyrolysis at high pressure are comparable. Comparing the observed rates of the desulphurization steps to those obtained under slow heating at high pressure treatments, rapid hydropyrolysis increases the frequency factors in the rate of release of organic sulphur to gas and tar by 2.5–10 times, while the frequency factors in the reduction rate of pyrite is suppressed by three to four orders. Rapid hydropyrolysis has potential as a pre-treatment process with high thermal efficiency for coal cleaning.

Nitrogen evolution during rapid hydropyrolysis of coal : Xu, W.-C. and Kumagai, M. Fuel, 2002, 81, (18), 2325–2334

Gasification of solid fuels is a partial oxidation process which converse the solid feedstock into syngas which can be used in a large number of applications e.g. power generation, manufacture of various chemicals and fuels (hydrogen, methanol, ammonia, fertilizers etc.). Not all of the gasification systems are suitable for energy vectors polygeneration with carbon capture and storage (CCS).This paper is proposing to evaluate various gasification technologies by mathematical modeling and simulation methods (especially for entrained flow types as these gasifiers are more suitable for implementing carbon capture technologies). In this paper a particular accent will be put on the selection of the most promising gasifier, as not all are appropriate for a carbon capture Integrated Gasification Combined Cycle (IGCC) applied for energy vectors poly-generation (with a particular focus on hydrogen and electricity co-production case) with Carbon Capture and Storage (CCS). For the selection of the most appropriate gasifier technologies the process were mathematical modeled and simulated with process flow modeling software (e.g. ChemCAD, Aspen). In the evaluation of various gasification technologies (e.g. Shell, Siemens, GE-Texaco, Conoco-Phillips etc.) a multi-criteria analysis was performed.

High pressure hydropyrolysis of coals by using a continuous free-fall reactor ☆

Rapid hydropyrolysis of coal was carried out at temperatures ranging from 923 to 1123 K and H 2 pressures up to 7 MPa by using a continuous free-fall pyrolyzer. The effects of the reaction conditions on product yields were investigated. Carbon mass balance was fairly good. It was revealed that a large amount of methane was produced due to the hydrogenolysis of higher hydrocarbons and the hydrogasification of char. The influence of pyrolysis temperature was significant on both reactions while H 2 pressure mainly affected the latter. A considerable amount of reactive carbon was formed during hydropyrolysis of coal. It was converted to methane at high temperatures and high H 2 pressures, while the hydrogasification of reactive carbon takes place relatively slowly at low temperatures and low H 2 pressures, resulting in a low overall carbon conversion. The coal conversions observed in the present study were much higher than those obtained with using reactors where the contact between coal particles and H 2 is insufficient.

Sulfur transformation during rapid hydropyrolysis of coal under high pressure by using a continuous free fall pyrolyzer☆

The behavior of sulfur transformation during rapid hydropyrolysis of coal was investigated using a pressurized, continuous free fall pyrolyzer under the conditions of temperature ranging from 923 to 1123 K and hydrogen pressure up to 5 MPa. The yields of sulfur converted to gas, tar and char were determined, together with the analyses of sulfur form distributions in coals and chars. The results showed that the decomposition of inorganic sulfur species was affected only by the temperature, while the increases in temperature and hydrogen pressure obviously enhanced the removal of organic sulfur from coal. The extent of organic sulfur removal was proportional to the coal conversion, depending on coal type. A significant retention of gaseous sulfur products by the organic matrix of the char was observed during hydropyrolysis of a Chinese coal above 1023 K, even under the pressurized hydrogen atmosphere. The kinetic analysis indicates that the rate of organic sulfur removal from coal was 0.2th-order with respect to the hydrogen pressure, and the activation energy for total sulfur removal and organic sulfur removal is 17–26 and 13–55 kJ/mol, respectively. The low activation energies suggest that the transformation and removal of sulfur from coal might be controlled by the diffusion and/or thermodynamic equilibrium during hydropyrolysis under the pressurized conditions.

Nitrogen evolution during rapid hydropyrolysis of coal

The behavior of nitrogen evolution during rapid hydropyrolysis of coal has been investigated at temperatures ranging from 923 to 1123 K and hydrogen pressure up to 5 MPa using a continuous free fall pyrolyzer. Three coals have been tested in this study. The dominant nitrogen gaseous species is ammonia, together with a little amount of HCN because most of HCN is converted to NH 3 through secondary reactions. The results show that the evolution of nitrogen in coal is caused mainly by devolatilization at temperatures below 973 K, while the evolution of volatile nitrogen in char is accelerated with increasing temperature and hydrogen pressure. The mineral matter in coal act as catalysts to promote the evolution of volatile nitrogen in char to N 2 apparently at high temperatures of 1123 K, as found during pyrolysis of coal by Ohtsuka et al. A pseudo-first-order kinetic model was applied to the evolution of nitrogen in coal during rapid hydropyrolysis. The model shows the activation energy for the nitrogen evolution from coal is 36.6–58.6 kJ/mol while the rate of the nitrogen evolution depends on hydrogen pressure in the order of 0.16–0.24.

99/00718 Staged pyrolysis of plastic mixtures. Process integrated pollutant and valuable material separation

The behavior of nitrogen evolution during rapid hydropyrolysis of coal has been investigated at temperatures ranging from 923 to 1123 K and hydrogen pressure up to 5 MPa using a continuous free fall pyrolyzer. Three coals have been tested in this study. The dominant nitrogen gaseous species is ammonia, together with a little amount of HCN because most of HCN is converted to NH3 through secondary reactions. The results show that the evolution of nitrogen in coal is caused mainly by devolatilization at temperatures below 973 K, while the evolution of volatile nitrogen in char is accelerated with increasing temperature and hydrogen pressure. The mineral matter in coal act as catalysts to promote the evolution of volatile nitrogen in char to N2 apparently at high temperatures of 1123 K, as found during pyrolysis of coal by Ohtsuka et al. A pseudo-first-order kinetic model was applied to the evolution of nitrogen in coal during rapid hydropyrolysis. The model shows the activation energy for the nitrogen evolution from coal is 36.6–58.6 kJ/mol while the rate of the nitrogen evolution depends on hydrogen pressure in the order of 0.16–0.24.

Rapid hydropyrolysis studies on coal and maceral concentrates

Rapid hydropyrolysis studies on coal and maceral concentrates

Rapid hydropyrolysis studies on coal and maceral concentrates

The primary devolatilization product distributions resulting from the rapid pyrolysis and hydropyrolysis of three coals and associated maceral concentrates were studied to assess the influence of coal and maceral type on reactivity and product formation. The influence of hydrogen on total product yield depended on both coal type and maceral group. In comparison with vitrinite and exinite concentrates, inertinite maceral concentrates showed high reactivity to hydrogen at high temperatures.

Hydropyrolysis yields in relation to coal properties

Rapid hydropyrolysis product yields were determined using a heated-grid apparatus for coals ranging from lignite to lower bituminous in rank. Least-squares regression analysis showed that there are significant correlations of total yield with, in order of decreasing correlation coefficient, BS volatile matter, O C atomic ratio, vitrinite reflectance, and carbon content. In addition, the yield of total liquids is significantly correlated with H C atomic ratio. The significance of these results is that they establish how standard analytical procedures may be used in the selection of coals for conversion processes based on hydropyrolysis. On the other hand, the relation of product yields to structural parameters such as aliphatic and aromatic hydrogen is seemingly more complex, as poor correlations are found with these parameters.

Assesment of internal dose from radionuclides — dosimetric and biokinetic models

Rapid hydropyrolysis of coal was carried out at temperatures ranging from 923 to 1123 K and H2 pressures up to 7 MPa by using a continuous free-fall pyrolyzer. The effects of the reaction conditions on product yields were investigated. Carbon mass balance was fairly good. It was revealed that a large amount of methane was produced due to the hydrogenolysis of higher hydrocarbons and the hydrogasification of char. The influence of pyrolysis temperature was significant on both reactions while H2 pressure mainly affected the latter. A considerable amount of reactive carbon was formed during hydropyrolysis of coal. It was converted to methane at high temperatures and high H2 pressures, while the hydrogasification of reactive carbon takes place relatively slowly at low temperatures and low H2 pressures, resulting in a low overall carbon conversion. The coal conversions observed in the present study were much higher than those obtained with using reactors where the contact between coal particles and H2 is insufficient.

Rapid Hydropyrolysis of Coal and Characterization of Derived Oil.

In order to characterize the oil derived from rapid hydropyrolysis of coal, Australian Loy Yang brown coal was pyrolyzed, using a bench-scale reactor of entrained flow type, at temperature of 700-950°C, hydrogen gas at 7MPa and residence time 6 to 7s. The products derived were hydrocarbon gases, CO, CO2, BTX, oil and char. The oil was distilled into 3 fractions (Fractions 1, 2 and 3 with the boiling points in the ranges of 400°C, respectively) and the composition of each fraction was analyzed. Fraction 2, a main component of the oil, thought to be compositional changeable intermediates generated during the process of the reaction, was further separated into saturates, aromatics and polars using HPLC, followed by analytical technique of FIMS and capillary gas chromatography, to study the composition of oil in detail.Reaction temperature in the range of 750-870°C, has a significant effect on both the yield and the composition of the oil. When the temperature is increased above 700°C, hydrocarbon gases and light oil, containing primary pyrolysis products, with short alkyl side-chains and many sorts of functional groups, remarkably increased in the yield, attributed to extensive thermal cracking of C-C bonds, etc., of polymeric units in coal, and the stabilization of light pyrolysis fragments by molecular hydrogen. This initial reaction almost ended at around 750°C Secondary reactions by hydrogenation became more pronounced, as temperature rose from 725 to 870°C. The yield of oil was influenced by the formation and decomposition rate of the oil, and the maximum yield was observed at around 750-800°C. The bonds of alkyl side-chains, hydroxyl group and N compounds, etc., were continuously broken up and a number of components contained in the oil decreased significantly. At 825°C, the content of unsubstituted aromatic compounds, such as naphthalene, phenanthrene, etc. in Fraction 2, exceeded 90%. At above 825°C, the decomposition of aromatic rings became the dominant reaction, causing sharp drop in the yield of oil and an increase in the yields of BTX and methane. Yield of BTX reached maximum at 870°C and then rapidly decreased with further rise in temperature, and at above 950°C, other aromatic compounds were not found.

Dynamic behaviour of sulphur forms in rapid hydropyrolysis of coal

Seven bituminous and sub-bituminous coals were rapidly hydrodesulphurized with a free-fall pyrolyser at atmospheric pressure, temperatures up to 1233 K and a heating rate of ≈ 6000 K s −1. The observed changes in the contents of sulphur forms were successfully simulated kinetically. Organic sulphur content was reduced by 54–92% and pyritic sulphur was almost reduced to ferrous sulphide sulphur in a very short reaction time of < 0.5 s. The release rate of volatile organic sulphur to tar and gas increased with increasing release rate of volatile matter and with increasing internal surface area. As the release rate of volatile matter changed from 8 to 43 s −1 with the increasing ratio of internal surface area of 1–4, the frequency factor of the release rate of volatile organic sulphur to tar and gas increased from 1.1 × 10 5 to 3.4 × 10 5 s −1 and that of organic sulphur to tar increased linearly from 3 × 10 4 s −1 to 2 × 10 5 s −1. The desulphurization results of total sulphur and char yield in rapid hydropyrolysis at atmospheric pressure and those in slow heating hydropyrolysis at high pressure are comparable. Comparing the observed rates of the desulphurization steps to those obtained under slow heating at high pressure treatments, rapid hydropyrolysis increases the frequency factors in the rate of release of organic sulphur to gas and tar by 2.5–10 times, while the frequency factors in the reduction rate of pyrite is suppressed by three to four orders. Rapid hydropyrolysis has potential as a pre-treatment process with high thermal efficiency for coal cleaning.

Characteristics of rapid hydropyrolysis of coals in a free fall pyrolyser

Five non-caking and two caking coals were pyrolysed rapidly using a free fall pyrolyser in a hydrogen stream at atmospheric pressure and at temperatures up to 1233 K, with a heating rate of ≈6000 K s −1. Sequential changes in the yield of volatile matter and char internal surface area were followed for several treatment times, from ≈0.1 to 0.4 s. The pyrolysis rate was determined by considering changes in particle temperature, diameter and apparent density. Average rate constants of pyrolysis were correlated with the increasing ratio of internal surface area in the early stage of pyrolysis. Rapid-hydropyrolysis char was more favourable for gasification than slow-heating pyrolysis char.

石炭の急速水素化熱分解における硫黄の挙動

The behavior of a variety of sulfur forms in coal is complicated in the hydropyrolysis prior to hydrogasification. The desulfurization characteristics which relate closely to the development of hydrogasification technology have been sur-veyed by giving attention to the process of change in the sulfur forms in the rapid hyd-ropyrolysis of coal.The variety of sulfur forms in coal is firstly described by referring to their origin. Experimental results are secondly shown concerning to the behavior of sulfur when steam coals are pyrolyzed under a slow heating condition in a hydrogen stream at nor-mal pressure. A desulfurization model proposed by the author and coworkers has been introduced with some simulated results. Pyritic and organic sulfur forms in solid are interrelated together through hydrogen sulfide in gas phase.Observed values are thirdly explained kinetically by the model for change in the sulfur-form distribution when coals are hydropyrolyzed rapidly with a heating rate 6×103°C/sec and a terminal temperature 960°C by using a free fall pyrolyzer. Good performance is noted that maximum extent of desulfurization 92% was achieved through the efficient reduction of organic sulfur which is hard to decrease with physic-al desulfurization methods. The desulfurization rate of organic sulfur strongly de-pends on the increase rate of internal surface area accompanied with hydropyrolysis. The difficulty of decomposition of refractory organic sulfur is another factor which de-termines the final extent of desulfurization.

Catalytic reactions of products from the rapid hydropyrolysis of coal at atmospheric pressure

The catalytic reactions of hydropyrolysis tars from a subbituminous coal have been studied at atmospheric pressure in a two-stage reactor. The first stage consisted of a fluidized-bed reactor that produced hydrocarbon gas and tars at high particle heating rates. The gas and tars were separated from char and ash and passed to a second-stage fixed-bed catalytic reactor, packed with a NiMo/γ-Al 2 O 3 hydrotreating catalyst. Detailed analyses of the compositions of the liquid products showed that the catalyst was responsible for cracking reactions of long-chain aliphatic groups to light hydrocarbon gases and aromatization reactions that produce highly condensed polycyclic aromatic hydrocarbons

Devolatilization Behavior in Rapid Hydropyrolysis of Coals in a Free-Fall Type Pyrolyzer

One caking and four noncaking coals were hydropyrolyzed rapidly in a freefalltype pyrolyzer which enabled coal particles to be heated in an order of 104°C/sec and accomplished a good extent of recovery of liquid products. Changeswere observed in volatile yield, caking property, and internal surface area withsuch short treatment times from ca. 0.1 to 0.6 sec. Devolatilization behavior waskinetically simulated assuming a hydropyrolysis mechanism.