Development in Techniques for the Recovery of Cl_2 Gas from CaCO_3
| Project/Area Number |
16360454
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Recycling engineering
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| Research Institution | Shizuoka University |
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Principal Investigator |
UENO Akifumi Shizuoka University, Engineering, Professor, 工学部, 教授 (30135420)
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| Co-Investigator(Kenkyū-buntansha) |
AZUMA Naoto Shizuoka University, Engineering, Associate Professor, 工学部, 助教授 (50192464)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥14,200,000 (Direct Cost: ¥14,200,000)
Fiscal Year 2005: ¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 2004: ¥9,500,000 (Direct Cost: ¥9,500,000)
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| Keywords | vinyl chloride / molten calcium chloride / chlorine gas / DEACON reaction / oxygen gas / silica / titanium oxide / calcium silicate / 塩化カルシウム / 塩素ガス / 酸化カルシウム / 熱力学的制約 / 溶融塩 |
|---|
| Research Abstract |
Disposal of waste polyvinyl chloride (PVC) is a serious problem for environmental safety because of the large quantity of CI ions included in the waste PVC. In order to overcome this problem, techniques to disperse the slurry containing Ca(OH)_2 or CaCO_3 into flue gases from inclnerators have been developed, where HCl involved in the flue gases was completely fixed in the calcium salts as CaCl_2. Waste solids thus yielded have been generally carefully grounded under the ground. However, this technique will not necessarily be an environmentally safe method, because CaCl_2sis well dissolved into the water under ground and widely spreads to cultivated fields for agriculture to react with other organic compounds for the production of undesired chlorinated organics.
Thus, the purpose of this research project is to recover Cl ions, as C_<12> gas, from waste CaCl_2 solids using a kind of DEACON reaction as follows ; CaCl_2+1/2O_2=CaO+Cl_2. Thermodynamically, this reaction is much endothermic,
… More
and even at 1173 K, where CaCl_2 is melted, ΔG is estimated to be +29 kcal/mol ; suggesting almost no reaction will occur. In order to accelerate the progress of reaction, a trace amount of Cl_2 gas and CaO yielded should be taken out of the reactor, which will thermodynamically push the reaction to proceed toward the right side. Then, we have tried to employ a large flowing rate of O_2 gas into the reactor, expecting flush up yielded Cl_2 gas out of the reactor. Another technique we applied is to mix SiO_2 or TiO_2 powders with CaCl_2 prior to the DEACON reaction, expecting the progress of the reaction between CaO yielded and SiO_2 or TiO_2. The reaction SiO_2 or TiO_2 with CaO means the production of SiCaO_3 or TiCaO_3, and thus the CaO yielded will be out of the reaction system. At the moment, optimum O_2 flow rate is 150 ml/min and optimum SiO2 addition is 3.0 g for the recovery of Cl_2 gas from 3.0 g of CaCl_2 at 1173 K. In these reaction conditions, more than 70 wt% of Cl ions in CaCl_2 was recovered as pure Cl_2 gas (not contaminated by HCl gas), which will be used again for the production of PVC. Less
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Report
(3 results)
Research Products
(25 results)
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[Book] 環境に優しい科学技術の開発2006
Author(s)
上野晃史(分担執筆)
Total Pages
306
Publisher
シーエムシー出版
Description
「研究成果報告書概要(和文)」より
Related Report
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