A continuous process for recovery of sulfur from natural gas containing low concentrations of hydrogen sulfide

A continuous catalytic process was developed to remove hydrogen sulfide from a natural gas stream using activated carbon as catalyst. The concentration range of hydrogen sulfide in the gas stream studied was 300–3000 ppmv (0.0126–0.126 moles/m³). Virtually 100 percent conversion of hydrogen sulfide was achieved by the combination of various parameters. The “field gas” employed in this study exhibited cracking of some heavier hydrocarbons and made the product sulfur slightly brown. These hydrocarbons should therefore be separated from the gas stream prior to the oxidation reaction. No carbon monoxide or carbon dioxide was produced during the oxidation of hydrogen sulfide. It is concluded that the process described herein has the potential for the removal of hydrogen sulfide as sulfur from a sour natural gas stream on a continuous basis and could therefore eliminate an environmental problem which now exists.     

氢气氛下半焦有机硫的脱除动力学

研究了半焦颗粒在氢气氛下有机硫脱除的本征动力学行为.实验采用微分反应器,研究结果表明,半焦颗粒的脱硫与气氛、温度和半焦硫含量有关.通过比较粒子反应模型和随机孔模型,粒子反应模型仅适合于处理半焦颗粒氢气气氛脱硫的初始阶段,而随机孔模型符合整个脱硫过程.实验和理论分析揭示了脱硫过程中煤中有机硫形态的转化.     

活性炭担载金属氧化物用于热煤气脱硫

以热煤气脱硫并回收单质硫为目的,考察了活性炭担载金属氧化物(M/AC)在中温范围150—250℃内,催化氧化硫化氢生成单质硫的研究。担载量1%(质量分数)的M/AC通过等体积浸渍法制得,在固定床上评价了其脱硫活性,并考察了温度、反应气氛等工艺条件对脱硫效果的影响。M/AC脱硫的活性顺序为:Mn/ACCu/ACCe/ACFe/ACCo/ACV/AC。通过DTG分析,硫化氢选择性氧化的主要产物是单质硫。M/AC上金属氧化物起主要的催化作用,催化硫化氢和氧气反应生成单质硫,生成的单质硫被吸附在活性炭的孔道中。     

多孔介质内H2S超绝热燃烧制氢的数值模拟

为探索H₂S在多孔介质内超绝热燃烧裂解制硫制氢的机理,采用计算流体力学(CFD)与CHEMKIN相结合的方法,使用标准k-ε湍流模型和一个17组分、57步复杂化学反应机理,模拟了H₂S在直径为3 mm的Al₂O₃圆球堆积成的多孔介质内的燃烧,模拟结果与实验数据基本吻合.模拟结果显示：多孔介质内H₂S的燃烧温度超过了绝热燃烧温度,为H₂S的裂解制硫制氢提供高温环境,富燃条件下H₂S部分地裂解生成单质硫和氢气.另外,对采用的复杂化学反应机理是否适用于多孔介质内H₂S燃烧时各向异性火焰的模拟作了有意义的探索.     

文昌13-1/2油田液化石油气铜腐超标治理方法的研究及应用

文昌13-1/2油田液化石油气(LPG)回收项目是中海石油(中国)有限公司湛江分公司首个海上LPG回收项目。近年来文昌油田LPG产品时而会发生铜腐测试不合格情况,本文通过对LPG系统硫化氢检测,LPG气样总硫含量测试以及铜片腐蚀产物的能谱测试,发现文昌油田LPG气样铜腐超标和硫含量超标有关。根据海上油田生产环境特点,拟采取湿法脱硫技术,直接加注脱硫剂的方法治理铜腐不合格问题。现场试验加药点选在进口压缩机进口,这样既可以给脱硫剂与硫化氢反应提供空间和时间,又可以在LPG系统较前端将硫化氢治理到较低水平,防止了硫化氢在LPG系统中的扩散。液化气脱硫剂以加注量50mL/min,在现场实践应用的一个月的时间里,可以有效地将铜腐指标从2a降低到1a,确保LPG产品符合国标标准要求。     

介质阻挡放电等离子体脱除沼气中硫化氢的实验研究

介质阻挡放电（DBD）等离子体技术是一种有效的气体污染物控制技术。开展了利用DBD等离子体技术脱除模拟沼气中硫化氢的实验研究,考察了放电能量密度、硫化氢初始体积浓度、停留时间以及含氧量对硫化氢脱除效果的影响,并分析了DBD等离子体反应器中脱除硫化氢的产物。结果表明,DBD等离子体能有效脱除模拟沼气中的硫化氢气体,脱除效率随放电能量密度、停留时间和含氧量的增大而提高,并且随硫化氢初始体积浓度的增加而下降;当模拟沼气处理气量为382mL／min、硫化氢初始体积浓度为4000×10^-6、氧气体积浓度为2％、能量密度为24．1kJ／L时,硫化氢气体被完全脱除,同时氧气的体积含量也低于0．5％,达到了国家规定的车用天然气标准内的硫化氢和氧气含量标准。根据产物分析,硫化氢的脱除产物主要为二氧化硫,少量的单质硫粉。     

F-T合成催化剂H2S中毒热力学和抗硫可行性预测

利用热力学基础数据对F-T合成催化剂硫化氢中毒的热力学进行了计算。在热力学上,Ru、Fe、Co的毒化在F-T合成反应可以发生的条件下均是自发过程。F-T合成反应体系中10^-8级浓度的H₂S即可使Ru基催化剂中的金属Ru生成RuS₂而中毒。Fe和Co相似文献   

Low-temperature catalytic decomposition of hydrogen sulfide on metal catalysts under layer of solvent

When hydrogen sulfide decomposition {2 H₂S ? 2 H₂?+?S₂^(gas)} is carried out in the flow regime at room temperature on metal catalysts placed in a liquid capable of dissolving H₂S and sulfur, the reaction equilibrium can be significantly (up to 100%) shifted to the right yielding the desired product – hydrogen. The process efficiency was demonstrated using aqueous solutions of monoethanolamine (MEA), sodium carbonate, which is widely used in industry for H₂S absorption from tail gases, and aqueous hydrazine as examples. IR and Raman spectroscopy data demonstrated that sulfur obtained in the solutions is in the form of diatomic molecules. DFT calculations showed that diatomic sulfur forms weakly bound coordinative complexes with solvent molecules. Some problems related to sulfur accumulation and recovery from the solvents are discussed.     

SOFC中低浓度干甲烷在Ni/YSZ阳极上的反应

固体氧化物燃料电池(SOFC)趋向于直接使用甲烷天然气为燃料,确定甲烷在固体氧化物燃料电池阳极发生的化学与电化学反应非常重要.以Ni/YSZ为阳极、YSZ板做电解质、LSM为阴极,用涂浆法制作电解质支撑的电池,研究低浓度干甲烷在固体氧化物燃料电池中的反应.改变甲烷浓度、电池工作温度、电解质厚度,用在线色谱测量不同电流密度下,阳极出口气体产生速率.根据阳极出口气体产生速率变化,分析干甲烷在阳极的反应变化.通过氧消耗计算和转移电子数的分析,说明甲烷在电池阳极发生不同类型的反应.电流密度小时,甲烷发生部分氧化反应.电流密度大时,发生氢氧化和CO氧化,部分甲烷发生总反应为完全氧化的反应.部分甲烷发生完全氧化反应的同时,部分甲烷仍发生部分氧化反应,但其反应速率随电流密度增加逐渐降低.甲烷浓度和试验温度增加,甲烷开始发生完全氧化的电流密度增加.     

Selective Partial Oxidation of Hydrogen Sulfide by the BrOx Cycle

Neutralization of the toxic gas hydrogen sulfide is an important step in almost every natural gas processing plant. A novel method for the conversion of hydrogen sulfide is a combination of bromination and oxidation reactions (BrOx). The first of those, the bromination of hydrogen sulfide, is investigated experimentally. An analysis of the potential by‐products reveals that their formation during the reaction can be excluded. Furthermore, a parameter study showed that reaction yields of up to 94 % are achievable by suitable reaction conditions.     

Low Temperature Catalytic Decomposition of Hydrogen Sulfide into Hydrogen and Diatomic Gaseous Sulfur

A new catalytic reaction of hydrogen sulfide decomposition is discovered, the reaction occurs on metal catalysts in gas phase according to equation $$2{\text{H}}_{2} {\text{S}} \leftrightarrow 2{\text{H}}_{2} + {\text{S}}_{2}^{{({\text{gas}})}}$$ 2 H 2 S ? 2 H 2 + S 2 ( gas ) to produce hydrogen and gaseous diatomic sulfur, conversion of hydrogen sulfide at room temperature is close to 15 %. The thermodynamic driving force of the reaction is the formation of the chemical sulfur–sulfur bond between two hydrogen sulfide molecules adsorbed on two adjacent metal atoms in the key surface intermediate and elimination of hydrogen into gas phase. “Fingerprints” of diatomic sulfur adsorbed on the solid surfaces and dissolved in different solvents are studied. In closed vessels in adsorbed or dissolved states, this molecule is stable for a long period of time (weeks). A possible electronic structure of diatomic gaseous sulfur in the singlet state is considered. According to DFT/CASSCF calculations, energy of the singlet state of S₂ molecule is over the triplet ground state energy for 10.4/14.4 kcal/mol. Some properties of gaseous diatomic sulfur are also investigated. Catalytic solid systems, both bulk and supported on porous carriers, are developed. When hydrogen sulfide is passing through the solid catalyst immersed in liquid solvent which is capable of dissolving sulfur generated, conversion of hydrogen sulfide at room temperature achieves 100 %, producing hydrogen in gas phase. This gives grounds to consider hydrogen sulfide as inexhaustible potential source of hydrogen—a very valuable chemical reagent and environmentally friendly energy product.     

Biofiltration control of pulping odors – hydrogen sulfide: performance,macrokinetics and coexistence effects of organo‐sulfur species

The work reported here describes the aerobic biodegradation of reduced sulfur compound mixtures in air streams by biofilters. Rates of removal of hydrogen sulfide as a sole substrate and in the presence of organo‐sulfur compounds were determined to see if there were any inhibitory effects of the organo‐sulfur compounds on the rate of hydrogen sulfide removal. Experiments were conducted in three bench‐scale biofilters packed with the mixtures of compost/perlite (4:1), hog fuel/ perlite (4:1), and compost/hog fuel/perlite (2:2:1), respectively. Hydrogen sulfide, the predominant odorous gas produced from kraft pulping processes, was used as the main pollutant (substrate). Other organo‐sulfur species (dimethyl sulfide and dimethyl disulfide), also emitted from kraft pulp mills, were used as competing (secondary) substrates in the waste gas stream. To describe rates of removal a Michaelis–Menten type kinetic equation was modified to incorporate the plug flow behavior of biofilters, and used in evaluating the pseudo‐kinetic parameters, V_max (the maximum removal rate) and K_m (the half saturation concentration), for hydrogen sulfide biodegradation, and the type of macrokinetic competition between hydrogen sulfide and the organo‐sulfur compounds. No significant differences in V _max for the three biofilters were observed. The V _max ranged between 136 and 147 g m⁻³ h ⁻¹, while the K_m varied from 44 to 59 ppmv for the three biofilters. Hydrogen sulfide elimination capacity was not affected by the presence of any of the organo‐sulfur species in all of the three biofilters, confirming earlier results that hydrogen sulfide removal in biofilters is independent of the presence of organo‐sulfur compounds mainly because of its easy biodegradability. © 1999 Society of Chemical Industry     

Selective catalytic reduction of sulfur dioxide with hydrogen to elemental sulfur over Co---Mo/Al2O3

The selective reduction of sulfur dioxide with hydrogen to elemental sulfur was studied over Co---Mo/Al₂O₃. When the feed conditions were properly optimized (SO₂/H₂ mole RATIO = 1:3), a sulfur yield of about 80% was achieved at temperatures around 300°C. The temperature is the lowest that has been reported so far for any catalyst for this reaction. The catalytic activity remained high and stable after presulfiding with 10% H₂S in hydrogen. Little influence on the catalytic activity was observed if the water content in the feed was kept below 11 vol.-%. The overall reaction consisted of two individual steps occurring on two different sites; sulfur dioxide was first hydrogenated to hydrogen sulfide on the metal sulfide phase, then followed by the Claus reaction of hydrogen sulfide with sulfur dioxide to produce elemental sulfur on the acidic sites of the alumina support.     

A theoretical analysis of non-chemical separation of hydrogen sulfide from methane by nano-porous membranes using capillary condensation

The potential of a nano-porous membrane to perform non-chemical separation of a gas mixture has been explored theoretically. Separation of hydrogen sulfide from its mixture with methane by capillary condensation has been selected as the model case. Because of its much lower condensation pressure compared to methane, hydrogen sulfide preferentially condenses in the fine pores and get transported by Poiseuille flow. Permeation rate up to 600 gmol/m² s bar has been achieved at a temperature lower than the critical temperature of the permeating species and higher than the critical temperature of the non-permeating species. Since methane has a much lower critical temperature than hydrogen sulfide, it gets physically dissolved in the condensed phase of hydrogen sulfide. An equation of state (EOS) approach ha s been adopted to calculate the fugacity of methane in the gas as well as in the condensed phase-in order to estimate its solubility. Computation of permeation flux of the condensed phase as well as of the separation factor of hydrogen sulfide has been performed over a wide range of temperature, pressure and gas composition. The separation factor which is expectedly a function of these variables, ranged from 700 to 100. The separation technique is expected to have an enhanced attraction since it is clean and does not require a solvent as in the conventional separation of acid gases.     

Oxidative absorption of hydrogen sulfide using an iron‐chelate based process: chelate degradation

BACKGROUND: Oxidative absorption of hydrogen sulfide into a solution of ferric chelates is studied in a stirred cell glass reactor. The experiments were performed to investigate the degradation of chelates sodium salt of nitrilotriacetic acid (NTA) (Merck), ethylenediaminetetraacetic acid diadisodium salt (EDTA) and diethylenetriaminepentaacetic acid (DTPA) at 313 K, pH 6, iron concentration 10 000 g L^?1 and Fe:chelate molar ratio 1:2. RESULTS: Oxidative absorption of hydrogen sulfide into a solution of Fe‐NTA was found to be more successful, therefore, further experiments with 10%, 50% and 100% concentrations of hydrogen sulfide were performed. It was shown that this process is applicable for removal of low and high concentrations of hydrogen sulfide. The effect of antioxidants using sodium thiosulfate was also studied in order to minimize degradation of NTA. The kinetics were studied and it was observed that the reaction appeared to be first order in ferric chelate with rate constants for 100, 50 and 10% hydrogen sulfide concentration: 0.035, 0.013 and 0.019 h^?1, respectively. CONCLUSIONS: Gas sweetening processes have commercial importance in natural gases, refinery of gases and biogas processing. Desulphurization and cleaning (i.e. removal of H₂S and CO₂) of petroleum gas and biogas is important to make the gas methane rich and to increase the calorific value of fuel. The same techniques of desulphurization and cleaning can be used for treating natural gas or petroleum gas. The desulphurization and cleaning processes can minimize the atmospheric emission of gases like SOx, NOx and CO. As the iron chelate based process is based on the principle of redox reaction of metal chelate with hydrogen sulfide, this method is very useful for desulphurization of petroleum gas and biogas. This work studied the effective use of Fe‐NTA solution for removal of high to low concentrations of H₂S as found in biogas and industrial waste gases. © 2012 Society of Chemical Industry     

A novel cyclic process for synthesis gas production

This paper reports a novel cyclic partial oxidation process for the production of synthesis gas with the in situ separation of oxygen from air. A perovskite-type oxide, La_0.8Sr_0.2Co_0.5Fe_0.5O_3−δ, is employed in the experimental study of the process as an oxygen retaining material. Air and methane are periodically brought into contact with the oxide packed in a fixed-bed reactor. The oxide, during the air step, exclusively retains oxygen while partial oxidation reaction occurs during the methane step utilizing the retained oxygen. Although combustion and cracking reactions occur in addition to the partial oxidation reaction during the methane step, high methane conversion is achieved and hydrogen and CO are produced with high selectivity.     

高硫煤加氢热解脱硫研究

在常压固定床上,温度450—750℃,氢气流速300—900 mL/m in和升温速度15℃/m in的实验条件下,对沟底高硫煤加氢热解脱硫的影响因素进行了研究。实验结果表明,适当增加氢气的流速,提高反应最终温度和延长停留时间,对高硫煤加氢热解脱硫效率的提高和降低残留物中的硫质量分数都是有利的;利用气相色谱研究了硫化氢气体的逸出规律,随着热解温度的提高,硫化氢气体逸出曲线表现为2个峰。研究认为,高温峰源于硫铁矿和噻吩类含硫化合物中硫的脱除,而低温峰源于脂肪族含硫化合物硫的脱除。煤脱硫反应的热力学也表明,随热解温度升高煤加氢热解脱硫分为2段。     

The influence of oxygen additions to hydrogen in their electrode reactions at Pt/Nafion interface

The influence of oxygen gas added to hydrogen in their electrode reactions at the Pt/Nafion interface was investigated using ac impedance method. The electrochemical cell was arranged in either electrolytic (hydrogen enrichment) or galvanic (fuel cell) mode. The impedance spectra of the electrode reaction of a H₂/O₂ gas mixture were taken in each mode as a function of the gas composition, electrode surface roughness and the cell potential. The spectrum taken for the anodic reaction of electrolytic arrangement confirmed the anodic oxygen reduction reaction (AOR, the local consumption of hydrogen by the added oxygen) by showing an independent arc distinguishable from that for hydrogen oxidation. But the independent arc was not revealed in the spectrum taken on a smooth (low surface area) electrode or on a Pt/C anode of the galvanic cell. At any cell current density, the electrolytic mode showed its anodic overpotential much higher (nearly three times higher at the current density of 100 mA cm⁻²) than the potential registered in galvanic mode implying that the oxygen gas in the mixture engages more active and independent AOR at the anode of the electrolytic cell.     

Kinetic studies on the reactions involved in the hot gas desulfurization using a regenerable iron oxide sorbent—II: Reactions of iron sulfide with oxygen and sulfur dioxide

In the hot gas desulfurization process using iron oxide sorbent, the regeneration of the sulfided iron oxide sorbent consists of two reactions: the oxidation of iron sulfide with air, and its reaction with the sulfur dioxide formed during the air oxidation. This part describes the kinetic studies on the reactions of iron sulfide (formed by the reactions of Fe₂O₃ with H₂CO mixture and subsequendy with H₂S) with oxygen and sulfur dioxide. The experimental and analysis procedures used are similar to those outlined in Part I of this paper.The activation energies for the oxygen and the sulfur dioxide reactions are found to be 15.63 and 17.5 kcal/mol, respectively. Notably, the product oxides formed in the two cases are different. With air, the reaction is fast and the final product is Fe₂O₃, whereas with SO₂, the major product is Fe₃O₄, which slowly oxidizes to Fe₂O₃ in a secondary step. Also, in the latter reaction elemental sulfur is formed.