Low pressure equilibrium between H2S and CO2 over aqueous alkanolamine solution

242-249The simultaneous absorption of H2S and CO2 in aqueous alkanolamine solution is of considerable commercial importance. The reversible nature of reactions always results in equilibrium partial pressure of CO2 and H2S over amine solution. A simple method is presented to determine the equilibrium partial pressure having very low loading of H2S and CO2 with the select-ion electrode. The entire equilibrium is divided into two parts, namely first equilibrium and the final equilibrium. A (H2S + CO2)- aqueous alkanol amine system is highly non-ideal. Therefore, an attempt has been made to correlate data by using 'final equilibrium' expression based on ideal behaviour and then introducing a lumped correction factor (β) to predict observed data between H2S-CO2 and diethanolamine solution. This methodology being process engineering friendly can be extended to other systems also

<span style="font-size:12.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#191919;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Low pressure equilibrium between H₂S and alkanolamine revisited</span>

125-133Absorption of H2S in aqueous a1kanolamine solution is of considerable commercial importance. A simple method is presented to determine the equilibrium pressure having very low loading of H2S, with the help of 'sulfide' ion-selective electrode. By this method H2S-DEA and H2S-TEA VLE-data were obtained at different amine concentration and temperatures. A theoretical analysis of equilibrium between H2S and aqueous a1kanolamine solution has been reviewed. A semi empirical model with a correlation parameter,β-factor, is introduced to predict the equilibrium between H2S and alkanolamines.</span

Catalytic wet oxidation of an aqueous stream containing anthraquinone and phthalocyanine class reactive dyes: Ecofriendly technology

129-136<span style="font-size:11.0pt;line-height: 115%;font-family:Calibri;mso-fareast-font-family:" times="" new="" roman";mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-US">The effectiveness of wet oxidation (WO) of anthraquinone (Chem Brill Blue R) and phthalocyanine (Cibacron Turquoise Blue G) class reactive dyes in presence of copper catalyst has been studied in the temperature range of 140-175°C and oxygen partial pressure of 0.345-1.380 <span style="font-size:11.0pt;line-height:115%;font-family:Calibri; mso-fareast-font-family:" times="" new="" roman";mso-bidi-font-family:arial;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">MPa <span style="font-size:11.0pt;line-height:115%;font-family: Calibri;mso-fareast-font-family:" times="" new="" roman";mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">The extent of COD and colour removal efficiencies have been measured and compared. COD reduction of more than 92% and almost 100% colour removal is observed during oxidation of these dyes. Copper sulphate (CuSO4) as a homogeneous catalyst is found to be very much effective in destruction of COD and colour of reactive dyes.</span

<span style="font-size:12.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#1A1A1A;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Recov<span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#434343;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">e<span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#1A1A1A;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">ry <span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#2E2E2E;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">of <span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#434343;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">s<span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#1A1A1A;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">ulphur from H_{<span style="font-size:12.0pt; line-height:115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#434343;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">2</span>}<span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#1A1A1A;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">S bearing <span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#2E2E2E;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">gas <span style="font-size:12.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#1A1A1A;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">with the help of <i>Thiobacillus f</i><i><span style="font-size:12.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:#434343;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">e<span style="font-size:12.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:#1A1A1A;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">rrooxidans</span></span></i></span></span></span></span></span></span></span></span></span>

5-11A biological process is proposed for the recovery of sulphur from hydrogen sulphide hearing gas. The process involves absorption of the gas in an aqueous, ferric sulphate solution wherein, it is converted to elemental sulphur and ferric is reduced to ferrous. Oxidation of ferrous sulphate, which is a rate determining step, is carried out using Thiobacilluss ferrooxidans as catalyst, immobilized on a Carbon support in a fluidized bed reactor. The experiments are carried out in both batch and continuous modes of operation. The effects of various parameters such as light, ammonium sulphate, urea, and carbon dioxide as additives, have been studied to get better insight into the process of oxidation of Fe 2+ to Fe3+. The absence of light and the addition of ammonium sulphate improved the oxidation rate of Fe2+. The use of urea as an additive showed substantial enhancement of the oxidation rate. As the catalyst loading is increased, the oxidation rate of Fe2+ is also increased. The performance of the reactor in continuous mode of operation has been evaluated at different flow rates of Fe2+ solution. Sulphur of high purity has been obtained from H2S gas. The reduced solution is then oxidized to ferric sulphate and reused partly in order to simulate commercial operation

Treatment of distillery waste after bio-gas generation: Wet oxidation

11-18A process scheme has been presented for treating the waste stream originating from bio-gas generation unit of distillery waste by wet oxidation after thermal pretreatment for membrane process. The objective was not only to make the stream suitable to meet futuristic standards but also to produce acetic acid. The pretreatment can achieve a 40% reduction in COD with 30% color reduction. The wet oxidation of pretreated waste was studied in the range of 180-225°C and oxygen partial pressure 0.69-1.38 MPa. Kinetic studies were performed with and without catalyst. The overall kinetics of distillery waste obeyed a two step mechanism namely, the fast oxidation of organic substrate followed by slower oxidation of low molecular weight compounds formed such as acetic acid. Homogeneous ferrous sulfate is found to be a suitable catalyst to treat the waste effectively, which increases the performance of wet oxidation. While noncatalytic wet oxidation at 220°C achieved a 60% reduction in COD during 120 mins with 95% color destruction, catalytic wet oxidation achieved this at 210°C. Catalytic .wet oxidation with FeS04 increases acetic acid formation. Also, addition of trace amount of hydroquinone significantly increased the acid formation alongwith enhanced rates of COD destruction

Mass transfer in packed columns: co-current (downflow) operation: 1 in. and 1.5 in. metal pall rings and ceramic intalox saddles: multifilament gauze packings in 20 cm and 38 cm i.d. columns

The theory of gas absorption accompanied by fast pseudo-mth order reaction was used to obtain values of effective interfacial area, a, in 20 and 38 cm i.d. packed columns which were operated co-currently (downflow). Values of a were obtained for 1 in. and 1.5 in. metal Pall rings; 1 in. stainless steel Pall rings, having length (height) to diameter ratio of 1.0, 0.75, and 0.5; 1 in and 1.5 in. ceramic Italox saddles; and stainless steel multifilament wire gauze type packing over a wide range of gas and liquid superficial velocities. The gas superficial velocity was varied from 30 to 255 cm/sec in the 20 cm i.d. column and 14 to 73 cm/sec in the 38 cm i.d. column. The liquid superficial velocity was varied from 0.2 to 3 cm/sec in the 20 cm i.d. column and 0.2 to 1 cm/sec in the 38 cm i.d. column. Different flow regimes, namely, trickle flow (film flow), pulse flow and transition from pulse to disperse flow, were covered. The values of a were found to be in the range of 0.6 to 2 cm<SUP>2</SUP>/cm<SUP>3</SUP> for the trickle flow (film flow) regime, and 2.4-5 cm<SUP>2</SUP>/cm<SUP>3</SUP> for the pulse flow regime. In the case of multifilament wire gauze packing (MFWGP) remarkably high values of a up to 16 cm<SUP>2</SUP>/cm<SUP>3</SUP> were obtained in the pulse to disperse flow regime

Gas absorption with photochemical reaction

Gas-liquid reactions can be activated by high energy radiations (photons). When gas absorption is accompanied by pseudo-first order reaction further enhancement in the specific rate of absorption can be realised for situations where either the reactive species in the liquid phase is activated or the dissolved solute gas is activated

Some aspects of NOX absorption

This article does not have an abstract

Kinetics of hydrogenation of palm stearin fatty acid over Ru/Al₂O₃ catalyst in presence of small quantity of water

52-63The liquid phase hydrogenation of palm stearin fatty acid was studied in the presence of 2% (w/w) water, using n-dodecane as solvent. The catalyst, 5% Ru/Al₂O₃ was found to be more effective than that of Ni catalyst. The presence of water enhanced hydrogenation rate for ruthenium-supported catalyst. The kinetics for palm stearin fatty acid hydrogenation over 5% Ru/Al₂O₃ catalyst was investigated in a slurry reactor in the range of temperature (393-423 K) and H₂ pressure (0.68-2.72 MPa). The rate of hydrogenation was described in terms of reduction in iodine value (IV) using power law model. The Langmuir–Hinshelwood type kinetic expressions for a single site mechanism with molecular adsorption of H₂ was proposed, and this model provided the best fit of the experimental data. The catalyst could be reused thrice without any loss in activity