Gas Turbine Direct Integration in the Context of Pinch Technology

Gas‐turbine‐based cogeneration systems have been widely used in different applications in recent years. Although the most common method of using gas turbine exhaust energy is through the generation of steam in a heat recovery boiler, there are some applications where the exhaust energy has been directly used for drying or process fluid heating. In this work, direct integration of a gas turbine with a process was fully investigated in the context of pinch technology. This investigation includes simple gas turbine and gas turbines equipped with recuperator and afterburner. It was found that the best thermodynamic efficiency in a direct gas turbine system is achieved when two conditions are met: first, turbine inlet temperature is maximized, second, optimum pressure ratio is that which yields the maximum specific network. Two total cost optimization methods were also introduced. The first method is based on the assumption that power produced equates to power demand. In the second approach the power export opportunity was also considered. Finally, illustrative examples have been presented to show how approaches can be applied in practice.     

A comparative simulation study of power generation plants involving chemical looping combustion systems

This work presents a simulation study on both energy and economics of power generation plants with inherent CO₂ capture based on chemical looping combustion technologies. Combustion systems considered include a conventional chemical looping system and two extended three-reactor alternatives (exCLC and CLC3) for simultaneous hydrogen production. The power generation cycles include a combined cycle with steam injected gas turbines, a humid air turbine cycle and a simple steam cycle. Two oxygen carriers are considered in our study, iron and nickel. We further analyze the effect of the pressure reaction and the turbine inlet temperature on the plant efficiency. Results show that plant efficiencies as high as 54% are achieved by the chemical looping based systems with competitive costs. That value is well above the efficiency of 46% obtained by a conventional natural gas combined cycle system under the same conditions and simulation assumptions.     

Performance analysis of integrated biomass gasification fuel cell (BGFC) and biomass gasification combined cycle (BGCC) systems

Biomass gasification processes are more commonly integrated to gas turbine based combined heat and power (CHP) generation systems. However, efficiency can be greatly enhanced by the use of more advanced power generation technology such as solid oxide fuel cells (SOFC). The key objective of this work is to develop systematic site-wide process integration strategies, based on detailed process simulation in Aspen Plus, in view to improve heat recovery including waste heat, energy efficiency and cleaner operation, of biomass gasification fuel cell (BGFC) systems. The BGFC system considers integration of the exhaust gas as a source of steam and unreacted fuel from the SOFC to the steam gasifier, utilising biomass volatilised gases and tars, which is separately carried out from the combustion of the remaining char of the biomass in the presence of depleted air from the SOFC. The high grade process heat is utilised into direct heating of the process streams, e.g. heating of the syngas feed to the SOFC after cooling, condensation and ultra-cleaning with the Rectisol^® process, using the hot product gas from the steam gasifier and heating of air to the SOFC using exhaust gas from the char combustor. The medium to low grade process heat is extracted into excess steam and hot water generation from the BGFC site. This study presents a comprehensive comparison of energetic and emission performances between BGFC and biomass gasification combined cycle (BGCC) systems, based on a 4th generation biomass waste resource, straws. The former integrated system provides as much as twice the power, than the latter. Furthermore, the performance of the integrated BGFC system is thoroughly analysed for a range of power generations, ～100–997 kW. Increasing power generation from a BGFC system decreases its power generation efficiency (69–63%), while increasing CHP generation efficiency (80–85%).     

Optimization analysis of dual-purpose systems

This paper aims to analyze dual-purpose systems focusing the total cost optimization; a superstructure is proposed to present cogeneration systems and desalination technologies alternatives for the synthesis process. The superstructure consists of excluding components, gas turbines or conventional steam generators with excluding alternatives of supplying fuel for each combustion system. Also, backpressure or condensing/extraction steam turbine for supplying process steam could be selected. Finally one desalination unit chosen between electrically-driven or steam-driven reverse osmosis, multi-effect and multistage flash should be included. The analysis herein performed is based on energy and mass conservation equations, as well as the technological limiting equation of equipment. The results for ten different commercial gas turbines revealed that electrically-driven reverse osmosis was always chosen together with both natural gas and gasified biomass gas turbines.     

Energy and water in Kuwait: A sustainability viewpoint, Part II

In Kuwait, the daily consumption per capita of electric power is 14,000 kWh, and of desalted water is 600 L. These are among the highest in the world, and the total consumption of each is almost doubled every 10 years. The cogeneration power desalting plants CPDP producing these two commodities consumed about 54% of the total 150 millions barrels of fuel consumed in the year 2005. If these consumption and production patterns prevail, the fuel oil produced in the country can be fully consumed locally in 30 years, with nothing left for export, the main source of income. The picture can be changed if better desalted water and power production methods are used. These include changing the desalting method from multistage flash MSF known by its high energy consumption to the more energy efficient seawater reverse osmosis SWRO; and power production method of steam or gas turbine cycles to combined gas/steam turbine combined cycle known of its high efficiency. The energy consumed by the air conditioning AC systems should be reduced by using better codes of building insulation and more efficient AC systems. Other conservation methods to reduce water consumption and the energy consumed by transportation are outlined in this paper.     

Optimal coupling of waste and concentrated solar for the constant production of electricity over a year

In this article, a biogas-based Brayton cycle is integrated with a concentrated solar power facility. The gas turbine hot flue gas and the molten salts are used to generate steam for the regenerative Rankine cycle. The process model is solved as a nonlinear optimization problem within a multiperiod scheme to decide on the contribution of the energy resources and the operating conditions of the facility to meet a certain demand of power over a year mitigating the absence of solar availability. The steam turbine is responsible for power production while the gas turbine works mainly as a combustion chamber. In the South of Spain, an excess of biogas is available during summer yielding a production cost of electricity of 0.17 €/kWh with an investment of 380 M€ for a production facility of 25 MW. This plant is not yet economic.     

煤炭热力学高效和化学高价值利用新工艺

提出一种煤炭热力学高效和化学高价值利用新工艺（TCCUC）,包括煤炭拔头技术-半焦富氧直燃制备燃气轮机高温工质系统-燃气发电-蒸汽发电系统-CO₂捕集技术-干馏拔头产物提质处理技术六个技术模块。该工艺通过煤干馏拔头和焦油加氢等技术,对煤中大分子碳氢化合物进行适当热解和对热解产物焦油加氢处理得到高价值的碳氢液体燃料,实现煤炭的化学高价值利用;通过高温过滤、半焦直燃、燃气轮机与蒸汽轮机相结合等方法,实现对煤炭燃烧过程中高位热能的充分利用,进一步提高热-电联产效率。     

基于IGCC电站空分系统的选型与配置

IGCC电站空分系统的选型与配置包括空分系统的整体化程度、大型空压机和增压机的驱动方式、空分装置的规模和系列数等要素.分析了独立的、部分整体化以及完全整体化等3种空分系统的优缺点,推荐采用部分整体空分系统;讨论了驱动大型空压机和增压机的蒸汽轮机、燃气轮机以及电动机等3种驱动方式的利弊,建议采用电机驱动;针对大型IGCC...     

FLOX® Steam Reforming for PEM Fuel Cell Systems

Primary energy savings and CO₂ reduction is one of the key motivations for the use of fuel cell systems in the energy sector. A benchmark of domestic cogeneration by PEMFC with existing large scale power production systems such as combined steam‐gas turbine cycle, clearly reveals that only fuel cell systems optimising overall energy efficiency (> 85%) and electrical efficiencies (> 35%) show significant primary energy savings, about 10%, compared with the best competing technology. In this context, fuel processing technology plays a dominant role. A comparison of autothermal and steam reforming concepts in a PEMFC system shows inherent advantages in terms of efficiency at low complexity for the latter. The main reason for this is that steam reforming allows for the straightforward and effective use of the anode‐off gas energy in the reformer burner. Consequently, practical electrical system efficiencies over 40% seem to be achievable, most likely by steam reformers. FLOX®‐steam reforming technology has reached a high state of maturity, offering diverse advantages including: compact design, stable anode off‐gas usage, high efficiency, as well as simple control behaviour. Scaling of the concept is straightforward and offers an opportunity for efficient adaptation to smaller (1 kW) and larger (50 kW) units.     

Operational optimization of industrial steam systems under uncertainty using data-Driven adaptive robust optimization

This article addresses the operational optimization of industrial steam systems under device efficiency uncertainty using a data-driven adaptive robust optimization approach. A semiempirical model of steam turbine is first developed based on process mechanism and operational data. Uncertain parameters of the proposed steam turbine model are further derived from the historical process data. A robust kernel density estimation method is then used to construct the uncertainty sets for modeling these uncertain parameters. The data-driven uncertainty sets are incorporated into a two-stage adaptive robust mixed-integer linear programming (MILP) framework for operational optimization of steam systems to minimize the total operating cost. Integer variables are introduced to model the on/off decisions of the steam turbines and electrical motors, which are the major energy consumers of the steam system. By applying the affine decision rule, the proposed multilevel optimization model is transformed into its robust counterpart, which is a single-level MILP problem. The proposed framework is applied to the steam system of a real-world ethylene plant to demonstrate its applicability. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16500 2019     

热功联产汽轮机在硫酸装置中的应用

介绍了云南云天化国际云峰分公司300kt／a硫磺制酸装置在现有装置SO2风机电动机末端增加汽轮机,形成汽轮机、减速箱、电动机、增速机、风机五合一机组的改造及使用情况。采用系统废热所产生的3．2～3．8MPa、410～450℃中压过热蒸汽驱动汽轮机以带动SO2主鼓风机及电动机,达到降低电耗、节约能源的目的。     

Status and Promise of Fuel Cell Technology

The niche or early entry market penetration by ONSI and its phosphoric acid fuel cell technology has proven that fuel cells are reliable and suitable for premium power and other opportunity fuel niche market applications. Now, new fuel cell technologies – solid oxide fuel cells, molten carbonate fuel cells, and polymer electrolyte fuel cells – are being developed for near‐term distributed generation shortly after 2003. Some of the evolving fuel cell systems are incorporating gas turbines in hybrid configurations. The combination of the gas turbine with the fuel cell promises to lower system costs and increase efficiency to enhance market penetration. Market estimates indicate that significant early entry markets exist to sustain the initially high cost of some distributed generation technologies. However, distributed generation technologies must have low introductory first cost, low installation cost, and high system reliability to be viable options in competitive commercial and industrial markets. In the long‐term, solid state fuel cell technology with stack costs under $100/kilowatt (kW) promises deeper and wider market penetration in a range of applications including a residential, auxillary power, and the mature distributed generation markets. The Solid State Energy Conversion Alliance (SECA) with its vision for fuel cells in 2010 was recently formed to commercialize solid state fuel cells and realize the full potential of the fuel cell technology. Ultimately, the SECA concept could lead to megawatt‐size fuel‐cell systems for commercial and industrial applications and Vision 21 fuel cell turbine hybrid energy plants in 2015.     

Modeling and simulation of motor/turbine processes in utility plant

To achieve safe operation and to improve economics it is imperative to monitor and analyze demand and supply of utilities and to meet utility needs in time. The main objective of motor/turbine processes is to manipulate optimal balances on steam and electricity in utility plants. The optimal operation of motor/turbine processes is by far the most important to improve economics in the utility plant. In order to analyze motor/turbine processes, steady state models for steam generation equipment and steam distribution devices as well as turbine generators are developed and analyzed in this work. In addition, heuristics concerning various operational situations are incorporated in the models. The motor/turbine optimal operation system is based on utility models and operational knowledgebase, and provides optimal operating conditions when the amount of steam demand from various steam headers is changed frequently. The optimal operation system also produces optimal selection of driving devices for utility pumps to reduce operating cost.     

燃气电站汽轮机组旁路系统设计

为了改善汽轮机组的启动性能,协调机、炉间的汽量平衡,减少机组循环的汽水损失,格尔木燃气电站设置了一套高低压两级串联旁路装置,缩短了启动时间,减少了工质损失和启动费用,对机组快速启动特别是热态启动更有利。     

渣油制氨流程改进

现代的燃气轮机是一种较高效的发动机，热功转化效率可达３３％左右，高于蒸汽动力循环．渣油制氨生产过程中需大量动力，如适当使用燃气轮机，合理回收燃机排气余热，并在使用燃机的条件下重新优化生产流程，就可使渣油制氨的吨氨能耗下降至３４ＧＪ以下，并可不用高压动力锅炉，投资和生产成本都可降低．     

Entwicklung eines Echtzeitanalyse‐Systems zur Charakterisierung von Brenngasgemischen in Gasturbinenkraftwerken

The efficient operation of gas turbines strongly depends on the fuel gas and its properties. Technical fuel gases typically represent multiple component mixtures with varying composition rather than consisting of only a single species. These fluctuations effect the combustion process and interventions are required to increase the efficiency and decrease the operational costs. In this article a laser based sensor system for the real‐time analysis of fuel gas mixtures is described and its application in a gas turbine power plant is demonstrated.     

On the reduction of desalting energy and its cost in Kuwait

All seawater desalting processes, multi-stage flash (MSF), multi-effect boiling (MEB), mechanical vapor compression (MVC) and seawater reverse osmosis (SWRO) consume significant amounts of energy. The recent increase of fuel oil cost raises the cost of energy consumed for desalting water and the final water cost, and creates more interest in using more energy efficient desalting systems.

The most used desalting systems by distillation (MSF and MEB) are usually combined with power plants in what is called co-generation power desalting plants, CPDP. Fuel is supplied to the CPDP to produce both desalted water D and power W, and the fuel cost is shared between D and W. Exergy analysis and equivalent work are among the methods used to determine the fuel energy charged to each product. When desalting systems, such as SWRO and MVC, are not combined with a power plant, the fuel energy can be directly determined from its electrical power consumption.

In this paper, the fuel energy cost charged to desalting seawater in the presently used CPDP in Kuwait is calculated based on exergy analysis. The MSF, known by its high energy consumption, is the only desalting method used in Kuwait. The MSF units consume 258 kJ/kg thermal energy by steam supplied to the brine heater BH, 16 kJ/kg by steam supplied to steam ejectors, and 4 kWh/m3 mechanical energy for pumping. These MSF units are operated either by:

(1) Steam extracted from extraction/condensing steam turbines EC/ST as in as in Doha West, Azzour, and Sabbiya CPDP. This practice is used in most Gulf area.

(2) Steam supplied directly from boilers as occurred in single purpose desalting plants as Al Shuwaikh plant; or in winter time when no steam turbines are in operation in the CPDP to supply steam to the desalting units.

The CPDP have limited water to power production ratio. While they can cope with the increase of power demand, it cannot satisfy the water demand, which is increasing with higher pace than the power demand.

The case of steam CPDP used in Kuwait is presented in this paper as a reference plant to evaluate the amount of fuel energy consumed to desalt water in MJ/m3, its cost in $/m3. The resulted high fuel cost calls for some modifications in the reference CPDP to lower the energy cost, and to increase its water to power ratio. The modifications include the use of an auxiliary back-pressure steam turbine ABPST supplied with the steam presently extracted to the MSF units. The power output of the ABPST operates MVC or SWRO desalting units; while the ABPST discharged steam operates LT-MEB desalting unit. The desalting fuel energy costs when applying these modifications are also calculated by the exergy analysis and compared with that present situation.

It is also suggested to increase desalted water output by using separate SWRO desalting units operated by the existing power plants of typical η_c = 0.388, or by new combined gas/steam turbines power cycle GT/ST-CC of typical η_c = 0.54 under construction. The SWRO with energy recovery is assumed to consume typical 5.2 kWh/m³ electric energy.     

节能新技术在合成氨技术改造中的应用

介绍三废流化混燃锅炉、高炉体锥形管式夹套副产中压蒸汽煤气炉、热功电联产汽轮机等技术的应用情况.使用三废混燃锅炉后,吨蒸汽煤耗下降至100kg,吨蒸汽节约用煤80kg,且尾气达标排放;将原φ2600mm造气炉改造为高炉体锥形管式夹套副产中压蒸汽煤气炉后,副产蒸汽温度提高了80℃,单炉发气量增加了1 000～1 500m3...     

A Thermodynamic Approach to the Integrated Design of a Combined Cycle Cogeneration Plant

A thermodynamically oriented approach for the integrated design of a combined cycle cogeneration plant (CCCP) meeting a given sites requirements for process steam and power has been developed. It has been shown that the most efficient plant, for a targeted stack temperature, is achieved when the gas turbine cycle is designed for maximum specific net work and the steam turbine cycle is designed for maximum cycle efficiency. Based on this approach a computer program for rigorous analysis has also been developed.     

Simulation of a Lignite‐Based Polygeneration System Coproducing Electricity and Tar with Carbon Capture

Lignite‐based polygeneration systems for coproducing tar and electricity with and without carbon capture and storage (CCS) were proposed and simulated. Predried lignite was pyrolyzed into coal gas, tar, and char. Coal gas was fired in a gas turbine after the cleanup process, while char was combusted in circulating fluidized‐bed (CFB) boilers. The polygeneration plant without CCS turned out to be more efficient than the conventional CFB power plant, suggesting that the former is a promising and efficient option to utilize lignite resources. Moreover, the performance and emissions of polygeneration plants with and without CCS were compared. It was shown that the more CO₂ is captured, the larger energy penalty it will cost. Therefore, a trade‐off should be made between low emissions and high efficiency.