Oil and gas production and their separation processes result in the emission of greenhouse gases (GHG) such as methane and carbon dioxide. In order to reduce the emission volume, membrane–based separation technologies deserve special attention. After reviewing the gas separation method in oil and gas section, we will discuss the roles of the CVD–based inorganic membranes. Thermally–stable, organic solvent resistant, and robust nano–filtration membranes are also strongly required for the purification of produced water. We also introduce the progress of the development of diamond–like carbon membranes, as well as some oil adsorbents for the separation and recovery of oil in produced water.
In recent years, environmental problems such as global warming and energy saving technologies have attracted considerable attention. Hydrogen has been recognized as a clean and efficient energy carrier and as the significant chemical in petrochemical production. Photocatalytic water splitting is an expected chemical process for hydrogen production because of its environmental–friendly nature and its potential for low–cost. The technology of photocatalytic water splitting ranges from development of photocatalyst to purification of hydrogen. A surface–modified CHA zeolite membrane with higher selectivity of H2/N2 (N2 is analogous gas to O2) was prepared to be utilized in hydrogen separation in an artificial photosynthesis process.
Membrane module capable of loading six silica membranes and small–scale membrane reactor for dehydrogenation of methylcyclohexane using that membrane module have been investigated in Inorganic Membranes Research Center, Research Institute of Innovative Technology for the Earth. Silica membranes were prepared by counter–diffusion chemical vapor deposition method. These membranes showed extremely high hydrogen permselective performance, over 1 × 10–6 mol m–2 s–1 Pa–1 as hydrogen permeance and 10,000 as ideal selectivity (H2/SF6). Comparing with thermodynamic equilibrium conversion, using the membrane reactor showed much higher conversion. Durability of the membrane reactor loaded one silica membrane was also evaluated for 1,000 h. Methylcyclohexane conversion was approximately constant value during durability test. In addition, durability of dimethoxydiphenylsilane–derived silica membrane was investigated under steam co–existed conditions using heattreated and non–treated membranes. Comparing influence of steam on permeation performances of these membranes, permeance decreasing ratio of heat–treated membrane showed lower value than that of non–treated membrane.
Membrane–based separation is one of the promising technology for simplifying processes and reducing energy consumption drastically in future chemical and petroleum industries. Silica–based membranes, such as SiO2 membranes, SiO2–ZrO2 membranes, or organo–silica membranes, show both robust properties and high–permeability, offering us great potential for applying them to harsh conditions where conventional organic membranes cannot work. Despite the increasing number of paper and patents of silica–based membranes, their industrial applications have yet to be fully realized, possibly due to lack of technologies on scaling–up and mass production. In order to effectively develop the scaling–up and mass production technologies of silica-based membranes, we have first developed the silica–based nano–porous ceramic substrates (φ 12 mm, Length 400 mm) with high–permeance of more than 10–5 [mol/(m2 s Pa)] and center pore size distribution of 1 ～ 5 nm, minimizing effects of membrane defects less than 0.1% of total flux. Top surface–coated silica–based membranes using the nano–porous ceramic substrates showed high–permeance with reasonable selectivity, e.g. H2 permeance of 5 × 10–6 [mol/(m2 s Pa)] with H2/SF6 permeation ratio of more than 2,000. In addition, an example of mass–producing apparatus of silicabased membranes are introduced.
Membrane separation and/or membrane–distillation hybrid process has attracted attention in industry because of their strong impact on energy savings in chemical processes. Compared to conventional distillation columns, these processes have the advantage of reducing operation and capital costs, however a few work has been done to conducted the economics of these processes. This study employed the simulation model by Aspen Plus, custom modeler and economic analyzer to evaluate separation, energy saving and economic performances. The membrane and membrane– distillation separation processes were economically superior to the conventional distillation process for separation of a propylene–propane mixture. In particular, a membrane separation process reduced energy consumption and total annual cost by 67.8 and 68.4% respectively in comparison with the conventional distillation process.
In recent years, RO membranes have further expanded the results of activities at large plants in the field of seawater desalination and wastewater reuse. In these plants, the raw water is usually treated as it is at normal temperature (probably 5 ℃ to 40 ℃). However, when the raw water exceeds 45 ℃, it is necessary to cool the raw water once for membrane treatment because the heat resistance of the RO membrane element is not high. In the case where the raw water is at a high temperature and the treated water is also used at a high temperature again, an operation of cooling the raw water, followed by membrane treatment and then reheating the treated water, is required, and the loss of thermal energy is large and uneconomical. In this paper, we introduce the application development of heat resistant RO membrane in Nitto Denko and the case of its merit.
Globally, water production from oil and gas fields has been more and more increasing and thus the treatment and/or the reuse of produced water has become one of the top issues in oil and gas industry. Produced water reinjection (PWRI) to “tight” or low permeable reservoirs requires high levels of removal of suspended solids (SS) and oil-in-water to prevent formation plugging. Reverse osmosis (RO) technology, which creates desalinated water for various ways of utilization, also requires exhaustive removal of SS and oil–in–water as pretreatment. Microfiltration by ceramic membranes is considered as an effective solution for these applications because ceramic membranes offer higher hydrophilicity, lower fouling by oil–in–water and broader chemical and thermal compatibilities. An industrial scale produced water treatment demonstration plant has been installed in an oilfield to test performance of ceramic MF membranes. The plant includes a crossflow filtration system which accommodates commercial ceramic membranes (180 mm Dia., 1,500 or 1,000 mmL) followed by an RO membrane unit. Seven months of the field demonstration allowed us to develop protocols for sustainable operation although feed water qualities varied very widely in terms of concentration of oil–in–water and other foulants. The filtrate contained SS and oil–in–water not higher than 1 mg/L and 10 mg/L respectively at all times during the test period. That means it has been proved that the ceramic membrane can be very effective for PWRI to tight reservoir and alleviate plugging risk. Silt–density–index (SDI) of the filtrate, an indicator of RO feed water quality was not higher than 3.0 and the average was 1.6, ; this indicates the membrane–filered water is appropriate for the RO feed.
Membrane technology has been widely applied in a wide spectrum of applications and has served as an important unit operation for both upstream and downstream processes. The membrane research, development and commercialization in Malaysia are experiencing exponential growth as exemplified by Advanced Membrane Technology Research Centre (AMTEC) Universiti Teknologi Malaysia (UTM), one of the National Higher Institution Centre of Excellence (HICoE) in the niche of Water Reclamation. This contribution focuses on the overview of the recent progresses of membrane science and technology for desalination and wastewater treatment undertaken at AMTEC, UTM. The innovations and progresses in membrane science and technology made in lab scale which eventually lead to numerous high impact publications as well as the translational research and up–scaling experiences are presented. Several take home messages are summarized based on the past experiences and future perspective of AMTEC.
In past twenty years membrane technology has made remarkable achievements in China due to the financial and policy supports from government and huge market needs from environmental protection. Firstly, the recent progresses on membrane technology in China have been introduced by analyzing the academic publications, patent applications and current standards. The results revealed that the development in China is significant but the influence and competitiveness on membrane technology are still need to be further enhanced. Then current status of membrane technologies in water treatment, namely, ultrafiltration & microfiltration, membrane bioreactor and reverse osmosis, have been introduced in detail.
Molecular dynamics (MD) simulation was used to evaluate the effect of the interaction between polymer membrane and a silica nanoparticle (SNP), and the influence of polymer membrane surface properties on adsorbing behavior of SNP. In MD simulation, the adsorption behavior of SNP was observed when polyethylene (PE) and polyvinyl alcohol (PVA) were used for the membrane models, though the SNP was not adsorbed when PE–PVA hybrid model was employed. In order to consider the differences in the behavior of SNP in each membrane model, the diffusion coefficient of water molecules at the vicinity of membrane surface and the interaction energy between SNP and membrane were calculated. It was found that the adsorption mechanisms were different in each membrane model. Furthermore, experimental verification of the results obtained from the MD simulation was also conducted, and it was suggested that the PE film has SNP adsorption performance. However, PVA film didn’t show the adsorption performance because dissolution of the PVA film inhibited the adsorption of SNP. It was suggested that MD simulation offers the method to evaluate the molecular scale interaction and can greatly contribute to accelerating new membrane development.
Monolayers of lanosterol (Lan) and 1,2–dioleoyl–sn–glycero–3–phosphocholine (DOPC) were prepared at the air/water interface, to investigate potential interaction of Lan with unsaturated lipid. Excess area values of DOPC/Lan mixture were almost negative at pressures below 30 mN/m, while an increase of compression modulus was obtained at Lan ≧ 50 mol%. Excess Gibbs free energy analysis revealed a favorable interaction between DOPC and Lan at high concentration, which could be responsible to weak but sure ordering effect of Lan in unsaturated lipid bilayers.
Polysulfone membrane is used for various applications for its superior separation performance and permeability. For hemodialyzer application, anti–thrombogenicity is required on the surface of polysufone membrane. It was found that NV polymer could significantly suppress platelet adhesion by controlling the mobility of bound water. Our product hemodialyzer “Toraylight” NV showed good biocompatibility in clinical practices. This biocompatibility was thought due to NV polymer containing on the membrane surface that suppressed fibrinogen adsorption. Therefore, it was hypothesized that exact control of polymer structure would increase the mobility of bound water and therefore enhance the suppression of all protein absorptions. Based on this thought, we successfully developed a second generation polymer that demonstrated improved anti–fouling ability for hemodialyzer application.