scholarly journals A Novel Process of H2/CO2 Membrane Separation of Shifted Syngas Coupled with Gasoil Hydrogenation

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 590
Author(s):  
Weirong Huang ◽  
Xiaobin Jiang ◽  
Gaohong He ◽  
Xuehua Ruan ◽  
Bo Chen ◽  
...  
Keyword(s):  
Coal Gasification ◽  
Membrane Separation ◽  
Pressure Ratio ◽  
Stable Operation ◽  
Total System ◽  
Separation And Purification ◽  
Membrane Area ◽  
System Pressure ◽  
Compressor Power ◽  
Hydrogenation Reactor

A novel process of membrane separation for H2/CO2 of shifted syngas coupled with gasoil hydrogenation (NMGH) is proposed. First, a new process, with two-stage CO2-selective and one-stage H2-selective membranes, was developed to substitute the conventional PSA separation devices to remove CO2 and purify H2 in coal gasification refineries to reduce energy consumption and investment costs. Then, the process was coupled with gasoil hydrogenation and the recycled H2 produced by the hydrogenation reactor could be further purified by the H2-selective membrane, which increased the H2 concentration of the hydrogenation reactor inlet by about 11 mol.% compared with the conventional direct recycling process, and the total system pressure was reduced by about 2470 kPa. At the same time, this additional membrane separation and purification prevented the accumulation of CO/CO2 in the recycled H2, which ensured the activity of the catalyst in the reactor and the long-term stable operation of the devices. Further, parameters such as compressor power, PI (polyimide)/PEO (polyethylene oxide) membrane area, pressure ratio on both sides of the membrane, and purity of make-up H2 were optimized by sensitivity analysis. The results showed that, compared with the conventional method, the NMGH process simplified operations, significantly reduced the total investment cost by $17.74 million, and lowered the total annual costs by $1.50 million/year.

scholarly journals Multiobjective Optimization Based on “Distance-to-Target” Approach of Membrane Units for Separation of CO2/CH4

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1871
Author(s):  
Ricardo Abejón ◽  
Clara Casado-Coterillo ◽  
Aurora Garea
Keyword(s):  
Ionic Liquid ◽  
Multiobjective Optimization ◽  
Oil Recovery ◽  
Membrane Separation ◽  
Pressure Ratio ◽  
Composite Membranes ◽  
Membrane Area ◽  
Technical Performance ◽  
Separation Of Co2 ◽  
Chitosan Composite

The effective separation of CO2 and CH4 mixtures is essential for many applications, such as biogas upgrading, natural gas sweetening or enhanced oil recovery. Membrane separations can contribute greatly in these tasks, and innovative membrane materials are being developed for this gas separation. The aim of this work is the evaluation of the potential of two types of highly CO2-permeable membranes (modified commercial polydimethylsiloxane and non-commercial ionic liquid–chitosan composite membranes) whose selective layers possess different hydrophobic and hydrophilic characteristics for the separation of CO2/CH4 mixtures. The study of the technical performance of the selected membranes can provide a better understanding of their potentiality. The optimization of the performance of hollow fiber modules for both types of membranes was carried out by a “distance-to-target” approach that considered multiple objectives related to the purities and recovery of both gases. The results demonstrated that the ionic liquid–chitosan composite membranes improved the performance of other innovative membranes, with purity and recovery percentage values of 86 and 95%, respectively, for CO2 in the permeate stream, and 97 and 92% for CH4 in the retentate stream. The developed multiobjective optimization allowed for the determination of the optimal process design and performance parameters, such as the membrane area, pressure ratio and stage cut required to achieve maximum values for component separation in terms of purity and recovery. Since the purities and recoveries obtained were not enough to fulfill the requirements imposed on CO2 and CH4 streams to be directly valorized, the design of more complex multi-stage separation systems was also proposed by the application of this optimization methodology, which is considered as a useful tool to advance the implementation of the membrane separation processes.

Compressor Issues for Hydrogen Production and Transmission Through a Long Distance Pipeline Network

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Fred Starr ◽  
Calin-Cristian Cormos ◽  
Evangelos Tzimas ◽  
Stathis Peteves
Keyword(s):  
Pressure Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Energy System ◽  
Pipeline System ◽  
Hydrogen Energy ◽  
Long Distance ◽  
System Pressure ◽  
Production Of Hydrogen ◽  
Plant Exit

A hydrogen energy system will require the production of hydrogen from coal-based gasification plants and its transmission through long distance pipelines at 70 � 100 bar. To overcome some problems of current gasifiers, which are limited in pressure capability, two options are explored, in-plant compression of the syngas and compression of the hydrogen at the plant exit. It is shown that whereas in-plant compression using centrifugal machines is practical, this is not a solution when compressing hydrogen at the plant exit. This is because of the low molecular weight of the hydrogen. It is also shown that if centrifugal compressors are to be used in a pipeline system, pressure drops will need to be restricted as even an advanced two-stage centrifugal compressor will be limited to a pressure ratio of 1.2. High strength steels are suitable for the in-plant compressor, but aluminium alloy will be required for a hydrogen pipeline compressor.

Characteristics of Stable Rotating Stall Cells in an Axial Compressor

2017 ◽  
Author(s):  
Adam R. Hickman ◽  
Scott C. Morris
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Pressure Ratio ◽  
Pressure Sensors ◽  
Axial Compressor ◽  
Field Measurements ◽  
Rotating Stall ◽  
Flow Coefficient ◽  
Stable Operation ◽  
Double Phase

Flow field measurements of a high-speed axial compressor are presented during pre-stall and post-stall conditions. The paper provides an analysis of measurements from a circumferential array of unsteady shroud static pressure sensors during stall cell development. At low-speed, the stall cell approached a stable size in approximately two rotor revolutions. At higher speeds, the stall cell developed within a short amount of time after stall inception, but then fluctuated in circumferential extent as the compressor transiently approached a stable post-stall operating point. The size of the stall cell was found to be related to the annulus average flow coefficient. A discussion of Phase-Locked Average (PLA) statistics on flow field measurements during stable operation is also included. In conditions where rotating stall is present, flow field measurements can be Double Phase-Locked Averaged (DPLA) using a once-per-revolution (1/Rev) pulse and the period of the stall cell. The DPLA method provides greater detail and understanding into the structure of the stall cell. DPLA data indicated that a stalled compressor annulus can be considered to contained three main regions: over-pressurized passages, stalled passages, and recovering passages. Within the over-pressured region, rotor passages exhibited increased blade loading and pressure ratio compared to pre-stall values.

Effects of Hole Pitch to Diameter Ratio P/D of Impingement and Film Hole on Laminated Cooling Effectiveness

2017 ◽  
Author(s):  
Weilun Zhou ◽  
Qinghua Deng ◽  
Wei He ◽  
Zhenping Feng
Keyword(s):  
Mass Flux ◽  
Pressure Loss ◽  
Pressure Ratio ◽  
Diameter Ratio ◽  
Hole Diameter ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
System Pressure ◽  
The Difference

The laminated cooling, also known as impingement-effusion cooling, is believed to be a promising gas turbine blade cooling technique. In this paper, conjugate heat transfer analysis was employed to investigate the overall cooling effectiveness and total pressure loss of the laminated cooling configuration. The pitch to film hole diameter ratio P/Df of 3, 4, 5, 6, combined with pitch to impingement hole diameter ratio P/Di of 4, 6, 8, 10, are studied at the coolant mass flux G of 0.5, 1.0, 1.5, 2.0 kg/(sm2bar) respectively. The results show that overall cooling effectiveness of laminated cooling configuration increases with the decreasing of P/Df and the increasing of the coolant mass flux in general. However P/Df smaller than 3 may leads to a serious blocking in first few film holes at low coolant mass flux. The large P/Di that makes the Mach number of impingement flow greater than 0.16 may cause unacceptable pressure loss. The increment of overall cooling effectiveness depends on the difference between the deterioration of external cooling and the enhancement of internal cooling. Pressure loss increases exponentially with P/Di and G, and it increases more slowly with P/Df that compared to P/Di and G. The mixing loss takes up the most pressure loss at low coolant mass flux. With the increasing of the whole pressure loss, the proportion of throttling loss and laminated loss becomes larger and finally takes up the most of the whole pressure loss. When the sum of throttling loss and laminated loss is greater than mixing loss, the increment of system pressure ratio is unreasonable that compared to the increment of overall cooling effectiveness.

Full-Scale Demonstration of Surface-Stabilized Fuel Injectors for Sub-Three ppm NOx Emissions

2004 ◽  
Author(s):  
Steven J. Greenberg ◽  
Neil K. McDougald ◽  
Leonel O. Arellano
Keyword(s):  
Pressure Ratio ◽  
Full Scale ◽  
Low Flow ◽  
Stable Operation ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Fuel Injectors ◽  
Air Inlet ◽  
Radial Profiles ◽  
Developed Surface

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOx emission performance. These injectors use a patented technique to form interacting high-flow and low-flow flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. This technology has been given the product name nanoSTAR™. Previous work involved the development of nanoSTAR technology from the proof-of-concept stage to prototype testing. Rig testing of single injectors and of two injectors simulating a sector of an annular combustion liner have been completed for pressure ratios up to 17 and combustion air inlet temperatures up to 700 K (800°F). This paper presents results from the first ever full-scale demonstration of surface-stabilized fuel injectors. An annular combustion liner, fitted with twelve nanoSTAR injectors was successfully tested up to a pressure ratio of 12 and combustion air inlet temperature of 700 K (800°F). NOx emissions were 2 ppm with CO emissions of 3 ppm both corrected to 15% O2. The combustion system exhibited excellent temperature uniformity around the annular combustor outlet with a maximum pattern factor of 0.16 and engine-appropriate radial profiles.

Numerical Investigation on the Effect of Bleed Port With Self-Recirculating Casing Treatment on the Stability of a 1.5-Stage Transonic Compressor

2019 ◽  
Author(s):  
Yiming Zhong ◽  
WuLi Chu ◽  
HaoGuang Zhang
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Stability Margin ◽  
Axial Position ◽  
Stable Operation ◽  
Stall Margin ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Compressor Efficiency

Abstract Compared to the traditional casing treatment, the self-recirculating casing treatment (SCT) can improve or not decrease the compressor efficiency while achieving the stall margin improvement. For the bleed port, the main design indicator is to reduce the flow loss caused by suction, while providing sufficient jet flow and jet pressure to the injector. In order to gain a better study of the bleed port stabilization mechanisms, the bleed configuration was parameterized with the bleed port inlet width and the bleed port axial position. Five kinds of recirculating casing treatments were applied to a 1.5-stage transonic axial compressor with the method of three-dimensional unsteady numerical simulation. Fifteen identical self-recirculating devices are uniformly mounted around the annulus. The numerical results show that the SCT can improve compressor total pressure ratio and stability, shift the stall margin towards lower mass flows. Furthermore, it has no impact on compressor efficiency. The optimal case presents that stability margin is improved by 6.7% employing 3.1% of the annulus mass flow. Expanding bleed port inlet width to an intermediate level can further enhance compressor stability, but excessive bleed port inlet width will reduce the stabilization effect. The optimal bleed port position is located in the blocked area of the low energy group at the top of the rotor. In the case of solid casing, stall inception was the tip blockage, which was mainly triggered by the interaction of the tip leakage vortex and passage shock. From radial distribution, the casing treatment predominantly affects the above 70% span. The reduction of tip reflux region by suction effect is the main reason for the extension of stable operation range. The SCT also has an obvious stability improvement in tip blockage stall, while delaying the occurrence of compressor stall.

Thermodynamic Assessment of Hybrid PSOFC/GT Systems for Mechanical/Electric Power Generation

2000 ◽  
Author(s):  
K. K. Botros ◽  
G. R. Price ◽  
R. Parker
Keyword(s):  
Power Generation ◽  
Electric Power ◽  
Gas Turbine ◽  
Life Cycle Cost ◽  
Pressure Ratio ◽  
Pollutant Emissions ◽  
Mechanical Power ◽  
Total Power ◽  
Specific Work ◽  
System Pressure

Hybrid PSOFC/GT cycles consisting of pressurized solid oxide fuel cells integrated into gas turbine cycles are emerging as a major new power generation concept. These hybrid cycles can potentially offer thermal efficiencies exceeding 70% along with significant reductions in greenhouse gas and NOX emissions. This paper considers the PSOFC/GT cycle in terms of electrical and mechanical power generation with particular focus on gas pipeline companies interested in diversifying their assets into distributed electric generation or lowering pollutant emissions while more efficiently transporting natural gas. By replacing the conventional GT combustion chamber with an internally reformed PSOFC, electrical power is generated as a by-product while hot gases exiting the fuel cell are diverted into the gas turbine for mechanical power. A simple one-dimensional thermodynamic model of a generic PSOFC/GT cycle has shown that overall thermal efficiencies of 65% are attainable, whilst almost tripling the specific work (i.e. energy per unit mass of air). The main finding of this paper is that the amount of electric power generated ranges from 60–80% of the total power available depending on factors such as the system pressure ratio and degree of supplementary firing before the gas turbine. Ultimately, the best cycle should be based on the “balance of plant”, which considers factors such as life cycle cost analysis, business and market focus, and environmental emission issues.

Failure Analysis of Flange Sealing Surface of Outlet Pipeline of Wax Oil Hydrogenation Reactor

2020 ◽  
Author(s):  
Jiqing Shi ◽  
Jielu Wang ◽  
Wenming Song ◽  
Chaopeng Huang
Keyword(s):  
Preventive Measures ◽  
Quality Data ◽  
Composition Analysis ◽  
Stable Operation ◽  
Penetration Testing ◽  
Manufacturing Defects ◽  
Service Environment ◽  
Equipment Operation ◽  
The Core ◽  
Hydrogenation Reactor

Abstract Hydrogenation reactor is the core equipment of various hydrogenation units or hydrogenation processes. Because of the harsh service environment, the difficult manufacturing technology, the high requirements and the expensive cost, the safety of hydrogenation reactor is a very important problem. The outlet flange of hydrogenation reactor in a petrochemical company suddenly cracked after several years of use. The maximum depth of the crack from the sealing surface to the depth of the flange is 165 mm, the circumferential cracking range is about 130 degrees. The crack is in a circumferential and curved line along the sealing groove, and has small bifurcations at the tip. In order to ensure the safety of equipment operation and prevent the recurrence of this kind of accident, the causes of flange failure were systematically analyzed and the preventive measures are formulated. This paper reviewed the manufacturing quality data of the failed flange, and carried out a series of tests and analyses, such as macroscopic inspection, penetration testing, ultrasonic testing, mechanical properties test, chemical composition analysis, metallographic structure analysis, finite element stress check and so on. Combined with the use environment and the operation parameters of the flange, we preliminarily analyze that the cause of flange cracking may be manufacturing defects. In order to avoid the failure of flanges again, it is recommended that the flanges of the same batch should be tested one by one to ensure the safe and stable operation of the device.

Replacement of Secondary Clarification by Membrane Separation—Results with Tubular, Plate and Hollow Fibre Modules

1999 ◽  
Vol 40 (4-5) ◽  
pp. 311-320 ◽  
Author(s):  
Berthold Günder ◽  
Karlheinz Krauth
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Hollow Fibre ◽  
Stable Operation ◽  
Membrane Systems ◽  
Process Technology ◽  
Mixed Liquor ◽  
Activated Sludge Processes

Membrane separation systems can replace the final clarification step to separate mixed liquor suspended solids (MLSS) in the activated sludge processes. Mixed liquor suspended solids concentrations as high as 20 g/l can be obtained compared with the typical 3-4 g/l for conventional activated sludge/secondary clarifier systems. This leads to much smaller reactor volumes. In addition, excellent, solids free effluent qualities can be achieved with this process technology. This paper reports about the parallel investigation of three membrane systems installed within or outside bioreactors of 7 to 9 m3 volume and flow rates from 1 to 3 m3/h. The different membrane modules were investigated: plate module (80 m2 membrane surface), hollow fibre module (80 m2) and tubular module (45 m2). At MLSS concentrations up to 25 g/l and water temperatures from 10 to 25°C a stable operation of the membrane systems was achieved for a period of more than one year. The energy consumption was approximately 1.5 kWh/m3 for the plate and hollow fibre and 3.0 kWh/m3 for the tubular module system.

An Investigation of the Use of Wet Compression in Industrial Centrifugal Compressors

2006 ◽  
Author(s):  
Ahmed Abdelwahab
Keyword(s):  
Pressure Ratio ◽  
Water Injection ◽  
Centrifugal Compressors ◽  
Power Requirement ◽  
Operating Range ◽  
Multi Stage ◽  
Direct Water Injection ◽  
Compressor Inlet ◽  
Wet Compression ◽  
Compressor Power

Industrial centrifugal compressors generally comprise a number of low pressure ratio intercooled stages. This is done primarily for the purpose of reducing the compressor power requirements and improving the operating range of the multi-stage compressor. In recent years, however, rapid increases in the per-kilowatt-hour prices both domestically and worldwide has led to renewed research efforts to further reduce the power requirements of this type of compression equipment. Several attempts have been made to use direct water injection as a means to overspray the compressor inlet to further reduce its power requirement. This paper presents an investigation into the use of this technology in industrial centrifugal compressors. A simple numerical method is presented for the computation of wet compression processes. The method is based on both droplet evaporation and compressor mean-line calculations. An assessment, based on the developed model, of the effectiveness of evaporative processes in reducing the compressor power consumption per stage is presented. The impacts on stage efficiency and operating range are also presented.

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