New Process for Complete Removal of H2S from Gas Streams and Conversion to Elemental Sulfur

2016 ◽  
Author(s):  
Conrad Ayasse
Keyword(s):  
Elemental Sulfur ◽  
Complete Removal ◽  
Gas Streams ◽  
New Process

New Process for Physico-Chemical Pretreatment of Dairy Effluents with Agricultural Use of Sludge Produced

1990 ◽  
Vol 22 (9) ◽  
pp. 93-100 ◽  
Author(s):  
Á Kárpáti ◽  
L. Bencze ◽  
J. Borszéki
Keyword(s):  
Field Experiments ◽  
Complete Removal ◽  
Grain Production ◽  
Molecular Weights ◽  
Physico Chemical ◽  
New Process ◽  
Agricultural Use ◽  
Removal Of Fat ◽  
Biological Methods ◽  
Dairy Effluents

A combined physico-chemical process is suitable for the effective pretreatment of dairy effluents, achieving almost complete removal of fat, and considerable reduction of protein content. The specific cost of COD removal using the process is only half or a third of that using aerobic biological methods. Depending on the chemicals used, further treatment or, in certain cases, agricultural utilization, of the sludge is possible. In addition, the components remaining in the effluent have low molecular weights, are easily degradable, and are very favourable as nutrients in municipal aerobic post-treatment. Investigation of the sludge showed that it did not contain any pathogen organisms and therefore its application on land is recommended. Laboratory and field experiments have shown that, with agricultural use of the sludge, increased plant growth and grain production were achieved.

Optimal Conditions for Bio-Oxidation of Biodesulfurization in Natural Gas Sweetening Process Using Thiobacillus

2015 ◽  
Vol 1104 ◽  
pp. 57-60 ◽  
Author(s):  
Qi Song Liu ◽  
Bo Xu ◽  
Jin Long He ◽  
Ru Sun ◽  
Hong Gang Chang
Keyword(s):  
Natural Gas ◽  
Production Rate ◽  
Alkaline Solution ◽  
Elemental Sulfur ◽  
Influence Factor ◽  
Maximum Yield ◽  
Superior Performance ◽  
Gas Streams ◽  
Airlift Loop ◽  
Recycle And Reuse

Hydrogen sulfide is a common composition of natural gas. It is an important problem to develop suitable natural gas desulfurization technology for the present situation of China. Now, a novel process of H2S abatement from gas streams has been investigated for chemical absorption of H2S using a weak alkaline solution followed by the oxidation of the absorbed sulfide to elemental sulfur by naturally occurring microorganisms and alkaline solution regeneration for recycle and reuse in the process. This method is currently attracting more and more interests of researchers, because it requires little equipment, is inexpensive and produces only elemental sulfur, thus minimizing the production of pollutants. The biological oxidation process of the absorbed sulfides to elemental sulfur by Thiobacillus thioparus TYY-1 was studied in an airlift-loop reactor (effective volume=20L).Two efficiency factors including hydraulic remain time and the air aeration quantity were inspected. The air aeration quantity is key influence factor of desulfuration rate and elemental sulfur production rate. The investigation demonstrated that the optimum hydraulic remain time was 4—6h under the influent concentration of S2- for 200 mg/L, and the best treatment effect of aeration was obtained at 120 —160L/h. With these conditions after 20 days of operation, the result showed superior performance of the bioreactor for desulfuration rate and elemental sulfur production rate, the conversion products were mainly sulfur and the production rate of SO42- was low. The removal efficiency of sulfide was more than 99.5% while the maximum yield of sulfur was 88% approximately.

scholarly journals Autotrophic denitrification via nitrate as an effective approach for removal of dissolved sulfide in anaerobic reactors

2020 ◽  
Vol 82 (8) ◽  
pp. 1628-1634
Author(s):  
Jéssyca de Freitas Lima Brito ◽  
Camylla Rachelle Aguiar Araújo ◽  
Gabriel Alfredo Garcia Neto ◽  
André Bezerra dos Santos ◽  
Marcos Erick Rodrigues da Silva ◽  
...  
Keyword(s):  
Organic Matter ◽  
Elemental Sulfur ◽  
Complete Removal ◽  
Minor Effect ◽  
Autotrophic Denitrification ◽  
High Concentration ◽  
Anaerobic Reactors ◽  
Dissolved Sulfide ◽  
Nitrate Supplementation ◽  
A Minor

Abstract This work assessed the effect of adding different concentrations of nitrate (50–300 mg ·L−1) on the removal of dissolved and gaseous sulfide in an anaerobic reactor treating synthetic effluent containing sulfate (100 mg ·L−1) and organic matter (1 g COD·L−1). Autotrophic denitrification, stimulated by the addition of nitrate, was demonstrated to be a very effective approach for removal of dissolved sulfide even in the presence of a high concentration of organic matter (complete removal with 50 mg mg·L−1). However, it had a minor effect on H2S(g). Sulfide remained partially oxidized to elemental sulfur even with excess nitrate (100–300 mg mg·L−1). Therefore, the competition for this electron acceptor between the autotrophic and heterotrophic denitrification pathways may have prevented the conversion of the generated sulfide into sulfate again. No evidence of inhibition of methanogenesis and sulfidogenesis was found during nitrate supplementation.

scholarly journals Ceria-based catalysts for the recovery of elemental sulfur from SO2-laden gas streams

2000 ◽  
Vol 62 (2-3) ◽  
pp. 145-158 ◽  
Author(s):  
Maria Flytzani-Stephanopoulos ◽  
Tianli Zhu ◽  
Yue Li
Keyword(s):  
Elemental Sulfur ◽  
Gas Streams

New Contact Etch Process for Embedded DRAM Applications

1999 ◽  
Vol 564 ◽  
Author(s):  
Chan-Lon Yang ◽  
Tong-Yu Chen ◽  
Keh-Ching Huang ◽  
Le-Tien Jung ◽  
Tsu-An Lin ◽  
...  
Keyword(s):  
Vertical Profile ◽  
High Selectivity ◽  
Active Regions ◽  
Complete Removal ◽  
Contact Processes ◽  
Process Chemistry ◽  
Layer Structures ◽  
New Process ◽  
Key Issues ◽  
Layer Contact

AbstractFor embedded DRAM (E-DRAM) devices with feature sizes of 0.25 µm and beyond, contact processes with low contact resistance and low junction leakage current are required. The contact etch process needs to etch through multi-layer structures with SiO2, SiON/SiN layers and stop on Ti-polycide gate and Ti-salicide active regions at the same time. The key issues include high selectivity to TiSix, vertical profile, complete removal of SiON/SiN cap layer and no polymer residues. In this paper, multi-layer contact etching without attacking TiSix is reported. Using new process chemistry, the new contact etch process has been demonstrated for the manufacturing of 0.25 µm E-DRAM and beyond.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

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