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Volume 56, Issue 3
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[in Japanese]1977 Volume 56 Issue 3 Pages 143-144
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (279K) -
Catalytic and Non-catalytic MethodShigeaki Kasaoka1977 Volume 56 Issue 3 Pages 145-158
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSOn the basis of the fundamental results obtained in our laboratory and the informations from the industrial fields, the catalytic and non-catalytic reduction of NOx in dirty gas containing SOx and dusts with NH3 were summarized.
In the catalytic process, the first difficult point is that some kinds of dusts (for example, vanadium, etc.) stick on the surface to block the entrance of pores and decay the activity of the catalyst as wollas the chemical changes of supporting material or main catalyst with SOx. The second point is that the unreacted NH3 and SOx react with H2O and O2 to form (NH4) HSO4 in the lower temperature-parts after the flue gas passed the high temperature-reactor, and that the accumulation of these crystalized solids bring the pressure drop and the corrosion of materials of apparatus. This is the same with in the non-catalytic process.
However, Fe2 (SO4) 3-(αFe2O3)-MoO3 (WO3)-TiO2, V2O5-MoO3 (WO3)-TiO2 catalysts etc. in many catalysts studied up to date are considerably endurable for SOx and dusts, active and selective for the reduction of NOx. The relationships between the operation conditions and the fractional NOx-removal over these catalysts were described.
On the other hand, in the non-catalytic process, the decay of the catalyst due to SOx and dusts becomes independent, but for the purpose of obtaining the higher fractional NOx-removal, the extremely high temperature of the neighborhood of 1000°C, the long residence time more than ca. 1-2sec and the excess NH3 are required. The effects of these operation conditions and the addition of H2, etc. on the fractional NOx-removal were described.View full abstractDownload PDF (1746K) -
Kiyoshi Aoki1977 Volume 56 Issue 3 Pages 159-166
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSPractical problems in the atomizer used in the conbustion systems are reviewed and some technical improvements which were recently carried out in Ishi-kawajima-Harima Heavy Industries Co. Ltd. are described.
Spilit flame burner. The burner was developed to reduce NOx emission by means of minor modification of cobustionm system, and is characterized in its fuel atomizer. The burner with grooved tip atomizer, a typical type of the burner, which has afew grooves at the opening of the atomizer tip forms split flame and yields lower NOx than the conventional burner.
Air blast atomizer. A new air blast atomizer named AFIT was developed to improve the combustion efficiency at the low load condition of jet engine. The test results of the AFIT combustor showed higher combustion efficiency at the low load codition and lower NOx emission at the high load condition than the conventional combustor which has the swirl type pressure atomizer.
Carbon deposit. In the development test of a gas turbine combustor, it was found that the circumferential uneveness of the fuel spray caused a local carbon deposit on inside the liner.
Atomizer life. In a field test it was found that the atomizer tips installed on a large boiler were often heated up to the annealing temperature of the metal, and these tips were remarkably weared by the fuel flow. The combustion test results of the weared atomizer tips showed the deterioration of combustion characteristics.View full abstractDownload PDF (890K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1977 Volume 56 Issue 3 Pages 167-172
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (612K) -
Composition of Evolved Gas and Material Balance of Activation ProcessKazuyoshi Kudo, Kiyoshi Terada, Akira Yokogawa, Mitsuyuki Mitooka, Kat ...1977 Volume 56 Issue 3 Pages 173-178
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThis report describes the composition of evolved gas and the material balance of the activation process of char.
It was assumed that the activation process consisted of two stages; the thermal decomposition and the activation of char.
Most part of the sulfur, which was introduced into char by sulfonation, was released as SO2 during the thermal decomposition of char at around 300-400°C. while, about 50% of the original sulfur contained in raw asphalt was released as H2S during the thermal decomposition of char at around 300-500°C., and about 25% of the original sulfur as H2S during the activation stage.
The formation of hydrocarbons was observed evidently in addition to SO2and H2S during the thermal decomposition at around 400-600°C., while H2 and CO formed through water gas reaction occupied 90% of the total gas generated during the activation stage.
The material balance of the activation stage was calculated from the total volume and composition of evolved gas as well as the ultimate analysis of asphalt, char and activated carbon.View full abstractDownload PDF (661K) -
Shigeki Morimoto, Eizo Ishiyama1977 Volume 56 Issue 3 Pages 179-186
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSNitric oxide (NO) was reduced by semi-coke in the temperature range of 400 to 700°C with or without oxygen and water vapor and the following results were obtained:
(1) Semi-coke with 6.5% or more volatile matter has the good activity in removing NO and its activity was almost independent on the size of particles. It has also nearly the same reactivity as that of coconut carbon and much better activity than that of the activated carbon from coal.
(2) The presence of oxygen in the reactant gas accelerated the rate of reduction of NO.Though water vapor did not give any effect on NO reduction in the absence of oxygen in the reactant gas, it showed retarding effect in the presence of oxygen.
(3) When the reactant gas contains oxygen, the ratio of CO to CO2 in the resultant gas was 0.6 to 0.7 and the consumption of the semi-coke was 1.1times larger than the theoretical value.
(4) Some of metals, for example, K, Na, Ni, Cu or Co, impregnated on the semi-coke showed good promoting effect to the NO reduction reaction.
(5) The rate of reaction was proportional to the concentration of NO in the gas, regardless of the content of oxygen and water vapor in it.
(6) Reduction of NO on semi-coke was helped by the production of hydrogen from it.View full abstractDownload PDF (1022K) -
Isao Mochida, Kazuma Amamoto, Keiko Maeda, Kenjiro Takeshita1977 Volume 56 Issue 3 Pages 187-195
Published: March 20, 1977
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe cocarbonization properties of the benzene soluble fraction (BS) of several pitches and benzene insoluble fractions (BI) of SRC pitches were studies changing their mixing ratio in order to evaluate their compatibility for the needle coke formation because the smallest BS content required may reflect its cocarbonization ability to facilitate the mixture with fusibility or suitable reactivity for the needle coke formation. More than 90% of BS content was necessary for the BS-BI mixture of poorest compatibility to give a needle coke, whereas only 10% of BS content was enough for the mixture of best compatibility.
Ethylene tar-BS of poor compatibility with SRC-BI was found to be modified to be compatible to give needle coke by a catalytic reaction with aluminum chloride at 260°C, whereas ferric or cupric chloride failed. Based on the analytical study of BS in adition to these results, the compatibility of pitch fraction was discussed from the structural viewpoint of pitches.View full abstractDownload PDF (4453K)
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