Removal of SO2 and NO from flue gas by wet scrubbing using an aqueous NaClO2 solution

This study used a NaClO₂/NaOH solution as the additive/absorbent to determine the extent of NO_x removal in a wet scrubbing system. A combined SO_x/NO_x removal system was also tested. The experiments were performed in a bench-scale spraying sieve tray wet scrubber in a continuous mode. The operating variables included NO and SO₂ concentrations, L/G ratio, molar ratio, and initial pH.

The results of the individual DeNO_x experiments show that the maximum DeNO_x efficiencies ranged from 3.1 to 12.6%. The results of the combined DeSO_x/DeNO_x experiments show that the maximum DeNO_x and DeSO_x efficiencies ranged from 36.6 to 71.9% and from 89.4 to 100.0%, respectively. The major parameters affecting NO_x removal efficiencies are the L/G ratio and the dosage of additive. The major parameter influencing DeSO_x efficiencies is the L/G ratio.     

DIAGENETIC EVOLUTION OF INCISED CHANNEL SANDSTONES: IMPLICATIONS FOR RESERVOIR CHARACTERISATION OF THE LOWER CARBONIFEROUS MARAR FORMATION, GHADAMES BASIN, WESTERN LIBYA

This paper assesses the diagenetic history of potential fluvial hydrocarbon reservoir rocks deposited within incised valley systems of the Lower Carboniferous Marar Formation in western Libya. Outcrop data were collected in the Tinedhan Anticline, located at the southern margin of the Ghadames Basin. Four discrete intervals with channelized sandstones were identified in a section dominated by alternating offshore mudstones and shallow-marine clastics. The incised channels were cut during major sea-level lowstands, and filled by fluvial sandstone packages up to 50 m thick. Fifty-eight samples from four different localities, representing three lowstand systems tracts, were analysed to obtain a statistically meaningful mineralogical and compositional dataset. In addition to burial compaction, three main diagenetic events influenced the reservoir quality of the sandstones. Firstly, early eodiagenesis involved kaolinitization of plagioclase grains. This began before subsequent calcite cementation, probably as a result of flushing by meteoric pore-waters. The deformation of kaolinite during later compaction resulted in the formation of pseudomatrix which further reduced porosity and permeability. Kaolinite is commonly transformed to illite at temperatures above 140°C in the presence of K-feldspar. Although K-feldspar was recorded in the samples, no illite was observed, suggesting that the Lower Carboniferous strata in the study area were not buried in excess of approximately 3.5 km. The second diagenetic phase was the precipitation of calcite cement, present either dispersed throughout the sandbodies or as concretions up to 2 m across, in both cases reducing reservoir quality. The high intergranular volumes (IGV) of calcite-cemented sandstones (ranging between 35% and 40%) suggest that cementation occurred at burial depths of <500 m. Sandstones without calcite cement have lower IGV of between 17% and 25% as a result of mechanical and chemical compaction. Stable C and O isotope analysis of the calcite cement also supports precipitation at shallow burial depths, indicating a meteoric pore-water source for the calcite. The third and final diagenetic stage was partial chloritisation of kaolinite during meso-diagenesis. The elevated temperatures required for this transformation indicate burial to a minimum depth of approximately 2.5 km, which is consistent with the compaction data. Despite these diagenetic effects, the fluvial sandstones have an average porosity of 12%, with a range from 0.5% up to 25%. Permeability measurements on four sandstone samples indicate that the development of pseudomatrix did not reduce permeability significantly.     

Efficacy of sodium chlorite as an inhibitor of enzymatic browning in apple slices

Sodium chlorite (SC) is an effective sanitizer for inhibiting microbial growth. This investigation was conducted to determine the efficacy of SC as a browning control agent for use on fresh-cut apple slices, applied alone, or in conjunction with organic acids. Additionally, the authors compared the efficacy of SC to that of acidified sodium chlorite (ASC) and to several other salts and examined the effect of pH and several different organic acids on efficacy of SC. The fresh-cut apple slices were dipped in treatment solutions for 1 min, then drained and placed in plastic containers at 20 °C for 24 h, and finally stored in polyethylene bags at 5 °C for 2 weeks. Color was measured periodically during storage. Lightness (L) values for all treated and control samples measured at 4 h, 24 h, and 2 weeks of storage were compared to L value for untreated samples measured immediately after cutting. Percent decrease in L-values was calculated for each sample at each time interval. Apple slices treated in ASC or SC solution had a significantly smaller decrease in L value indicating less browning than those treated in citric acid or water control at 4 h (P < 0.01), and with the exception of 1 g L⁻¹ ASC and 0.1 g L⁻¹ SC, all other ASC and SC treated slices still had significantly less browning than those for the water control (P < 0.01) at 24 h. After 2 weeks of storage, only SC (0.5–1.0 g L⁻¹), sodium bisulfite (0.5 g L⁻¹) and calcium l-ascorbate (10 g L⁻¹) continued to inhibit browning. Treatment with 0.5 g L⁻¹ SC and pH adjusted in the range from 3.9 to 6.2 using citric acid (CA) reduced browning more effectively than 0.5 g L⁻¹ SC without pH adjustment. Two organic acids, salicylic acid and cinnamic acid, when added to SC solution, were found to achieve even better inhibition of browning than CA at the same pH value.     

Chlorate Formation in Chlorine Dioxide Delignification—An Analysis via Elementary Kinetic Modeling

Abstract

Elementary kinetic modeling was used to study the mechanism of chlorate formation in chlorine dioxide delignification. Reaction conditions reflecting typical industrial processes (T = 50°C, pH 1.5–4) were examined. Fe mediated Cl(III) decomposition and a reaction between hypochlorous acid and chlorous acid (or their equilibrium counterparts) were found to be the major reaction routes responsible for chlorate formation at pH < 3. The latter route accounts for chlorate formation at pH ≥ 3. The rate of chlorous acid (HClO₂) self-decomposition was too slow either to compete against the other routes (pH < 3) or to yield notable amounts of chlorate within the given time frame (pH ≥ 3). The results suggest that chlorate formation could be suppressed, without adverse effects on chlorine dioxide regeneration, by aiming for end pH 3–3.5, ensuring a moderate chloride ion concentration and by favoring concentrated solutions/suspensions.     

块状水钙铝榴石玉的点状绿研究及其鉴别

极椐显微镜下、红外光谱和Ｘ射线衍射的研究，表明块状水钙铝榴石玉的主要矿物成分是水钙铝榴石，并有含量不等的透辉石和方解石等。它的折射率为１．７２０左右，相对密度为３．４０～３．５０。在水钙铝榴石矿物中分布有密集程度不等的点状绿，这些点状绿多呈圆形或泪滴状，其第径约为０．１～１．０ｍｍ。每个点头绿的中心都有大小为０．０１～０．５０ｍｍ的黑斑。多数黑斑中心由一个黑点组成，但也有由璜工两个以上的黑点构成。     

西湖凹陷古近系及新近系储层砂岩自生高岭石分布特征及形成机制

在西湖凹陷古近系及新近系储层砂岩中,自生高岭石是含量仅次于碳酸盐的第二大自生矿物,主要是长石等铝硅酸盐矿物溶解的产物;自生高岭石含量与砂岩碎屑中的长石含量有着明显的负相关性,自生高岭石含量在凹陷中呈现的"东西分带、南高北低"的分布特点与成岩作用过程中有机酸和大气水对长石等铝硅酸盐的溶解作用有关,其中有机酸作用明显强于大气水。西湖凹陷平湖组在西斜坡具有比中央反转带明显高的自生高岭石含量,南部地区相对北部地区具有相对较高的高岭石含量,说明西斜坡平湖组和南部地区具有更好的次生孔隙形成条件,其储层质量更好。     

离子膜电解工序中盐酸使用的探讨

介绍了离了膜电解槽装置各部分对盐酸的使用标准、品质的要求、使用盐酸的原理等不同要求及电解工序对盐酸的使用情况。     

西峰油田庄58井区长8_1储层出水原因

西峰油田庄58井区长81油层厚度大,储层物性较好,测井解释含油饱和度较高,油层打开后多为高含水,生产能力低。在对西峰油田庄58井区长81储层基本地质特征进行研究的基础上,选取具有代表性的6块样品岩心进行了核磁共振可动流体评价研究,并采用铸体薄片和电镜扫描等手段,针对长81低渗透储层出水原因进行了分析研究。结果表明：绿泥石薄膜厚度越大往往可动流体饱和度越小。亲油性绿泥石薄膜吸附原油中重质组分是测井解释为油层或者油水层、但是打开后却出水不出油的主要原因。     

氧碳同位素在湖相自生碳酸盐研究中的应用

在各种湖泊的沉积物研究中,自生碳酸盐氧碳同位素指标得到了广泛的应用。通过氧碳同位素分析实验,可以利用湖泊次生碳酸盐氧碳同位素恢复湖泊的古气候、古盐度和古温度。在样品分析测试时也应注意外源碳酸盐岩与湖泊自生生碳酸盐岩的区分。     

自生“加大”含铁白云石胶结物特征及对致密砂岩储层的影响——以鄂尔多斯盆地陇东地区延长组4+5段为例

随着油气勘探的不断深入,致密砂岩储层越来越受到人们的关注,特别是关于致密化的成因及油气充注的时间。利用岩石学、岩石地球化学以及储层物性资料,综合分析鄂尔多斯盆地陇东地区延长组4+5段中含铁白云石胶结物产出特征、成因及其对储层质量的影响。研究表明：自生含铁白云石主要以白云岩岩屑的“次生加大边”形式出现,其形成与早成岩晚期碎屑白云岩的压溶和Fe质交代有关;少量含铁白云石交代长石颗粒。岩石粒度、黑云母碎屑含量、沉积微相控制含铁白云石胶结物的含量与分布,进而控制储层质量。在镇原和环县地区含铁白云石胶结物的含量高于华池和白豹地区;在水下分流河道中上部和河口坝中部,含铁白云石胶结物含量有增加的趋势。黑云母等碎屑的蚀变可能是最主要的Fe质来源。在水下分流河道底部砂体中,含铁白云石胶结物的含量一般小于3%,孔渗性整体较好;在水下分流河道顶部砂体中,这种胶结物的含量通常大于3%,储层质量一般较差。该研究成果将对相似地质条件下致密储层形成机理的分析提供一定的依据。