Assessment of localized corrosion in carbon steel tube-grade AISI 1045 used in output oil–gas separator vessel of desalination unit in oil refinery industry

In this research, we aimed to investigate the level of damage occurred in the steel tube material grade CK45 (AISI 1045) after a short period of service in an output desalination unit of an oil refinery industry. Visual examinations revealed that the material of the failed tube had significant thickness reduction and also localized corrosion damage. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction spectrum show that the corrosion products mostly consist of oxygen as the main element and slightly sulfur. Metallographic observations on the failed sample show that the observed pinholes were initiated on the inner surface of the tube sample where the surface was exposed to a possible mixed corrosive gas of H₂S, CO₂, and naphthenic acid. It is assumed that a severe thickness reduction has been initially taken place from the inner surface of the tube, and consequently the condensation of byproducts led to development of a localized corrosion and formation of pinholes due to flow stream of corrosive exhausted gases in output oil–gas separator vessel of the desalination unite. Presence of metallic elements in the EDS analysis such as calcium, magnesium, potassium, aluminum, manganese, silica, and zinc confirmed the possibility of condensation of corrosive compounds on the inner surface of the carbon steel tube grade CK45 in output oil–gas separator vessel of desalination unit. Microhardness measurements confirm that the steel tube has no hardness change in its core and outer surface. However, slight reduction in hardness is noticed near the inner surface of the tube sample which can be attributed to the presence of the pinholes. Electrochemical corrosion studies were carried out in the corrosive media filled up with a NACE ID 182 solution. Electrochemical investigations revealed that the corrosion products formed are typically porous which cannot provide a protective layer on the surface of the steel tube sample. Finally, recommendations mainly include application of protective coatings on the inner surface of the tube sample, and/or substitution of more resistive alloys with lower susceptibility to corrosive environments. Moreover, operational conditions such as temperature, water to oil ration and addition of any emulsifiers should be precisely controlled in order to decline any unpredicted fluctuations in output desalination unit’s products.     

Performance evaluation of a two-stage silica gel + water adsorption based cooling-cum-desalination system

The first objective of this paper is to show that a single-stage adsorption based cooling-cum-desalination system cannot be used if air cooled heat rejection is used under tropical conditions. This objective is achieved by operating a silica gel + water adsorption chiller first in a single-stage mode and then in a 2-stage mode with 2 beds/stage in each case. The second objective is to improve upon the simulation results obtained earlier by way of empirically describing the thermal wave phenomena during switching of operation of beds between adsorption and desorption and vice versa. Performance indicators, namely, cooling capacity, coefficient of performance and desalinated water output are extracted for various evaporator pressures and half cycle times. The improved simulation model is found to interpret experimental results more closely than the earlier one. Reasons for decline in performance indicators between theoretical and actual scenarios are appraised.     

The viability of hydrogen storage to supplement renewable energy when used to power municipal scale reverse osmosis plant

This paper investigates the viability of using hydrogen energy storage to supplement renewable energy when used to meet a significant and fundamental human need, in this case, large-scale drinking water supplies for around 50,000 people in Newhaven, in South East England, and in Massawa in Eritrea.     

海水淡化技术的现状及其应用

比较了海水淡化和远程调水在成本及环境影响等方面的优劣,介绍了海水淡化目前采用的主要技术,以及我国目前海水淡化的进展,指出从可持续发展的角度来看,海水淡化具有相当的优势。     

中东原油破乳剂的合成与评价

开发了一种适合加工中东原油的新型破乳剂,通过采用提高破乳剂相对分子质量和复配的方法,提高破乳剂的破乳效果和广谱性,对如何提高破乳剂的适应性和使用效果进行了高温和低温试验研究。该破乳剂适合多种中东原油,且具有用量少、效率高的优点,对于中东原油,在破乳剂用量为5～10μg／g时,脱盐率大于95％,脱后原油的盐含量可以达到深度电脱盐指标。     

超滤用于五道明胶脱盐

采用明胶含量为6．7％,电导率为3620μS/cm的五道明胶溶液作为试验对象,应用平板式超滤试验装置进行了脱盐试验．探讨了明胶生产过程中第五道胶液超滤脱盐的可行性及其工艺条件．结果表明,操作压力以0．5～0．6MPa为宜;运转液温度宜保持在40～45℃．超滤脱盐采用在运转过程中逐渐加入洗脱水,使明胶溶液中的盐分随水透过超滤膜,从而达到脱盐的目的．加入和透过的洗脱水达到原液的3．5倍时,明胶溶液的电导率降低至350μS／cm,达到了脱盐要求。     

进口原油掺炼污油的超声波破乳研究

以中国石化齐鲁分公司胜利炼油厂第二常减压装置加工的典型原油为研究对象,在实验室超声波-电脱盐动态模拟评价装置上进行了进口混合原油掺炼胜利重污油的脱盐脱水研究。结果表明:在无超声波作用时,掺炼重污油的混合原油脱后含盐量为4.9mg/L,采用超声波强化破乳后,脱后原油含盐量为2.8mg/L。说明超声波有较好强化破乳脱盐脱水作用。     

反渗透工程的应用及发展趋势

综合叙述了反渗透技术在海水、苦咸水淡化,纯水、超纯水制备,分离、浓缩、提纯和废水资源化及中水回用中的应用情况及其发展趋势．     

山东长岛县反渗透海水淡化工程

本文对国家重点科技攻关项目－长岛1000吨／日反渗透海水淡化示范工程的概况作综合介绍。     

艾比湖水盐变化及其影响研究

从湖泊水文要素出发，基于湖泊和流域的关系，对半个世纪以来艾比湖面积、矿化度等水文要素变化趋势进行了分析，并对变化原因进行了探讨。结果表明：相对封闭及较小尺度的流域面积等自身特性，决定了其水资源系统自我调节能力的脆弱性；而近年流域内的人类活动，增大了降水径流的滞留时间和蒸发作用，最终导致汇入湖泊的水量不断减少，矿化度在湖水量不断减少的情况下浓缩升高。