石化企业蒸汽使用系统分步操作优化

大型的石化企业中,蒸汽使用系统将来自锅炉的新鲜蒸汽转化为工艺系统需要的电力和一定压力的蒸汽,蒸汽使用系统蒸汽分配效率的高低直接关系着整个石化企业的能源利用率。蒸汽使用系统中汽轮机的热效率不同,背压汽轮机的热效率最高,并且在满足用户对热量需求的同时能副产电力。文章依据背压汽轮机的的特点,提出了蒸汽动力系统的分步优化方法:用户对蒸汽的需求优先使用背压汽轮机排气提供,同时最大限度副产电力;对电力的需求不足部分由凝气轮机满足,建立分步优化的模型。使用分步优化模型对某石化企业蒸汽动力系统进行优化,结果比使用一步优化方法的优化结果节能效果更显著。     

考虑不确定汽电需求的蒸汽动力系统优化设计

蒸汽动力系统优化设计不仅要保证系统全周期总费用最小,还要保证系统具有一定可操作性应对各种不确定变工况影响。本文提出了同时考虑汽电需求确定性多周期变化以及燃料、电力价格,汽电需求不确定性变化的蒸汽动力系统优化设计策略,专门提出不确定变化参数对优化目标及约束的影响以及数学表达,建立混合整数线性规划(MILP)优化模型进行求解,并应用于某石化企业蒸汽动力系统优化设计。实例设计结果表明,与按照传统策略设计结果相比,应用本文提出的考虑不确定参数的设计策略获得的优化方案,具体设计了针对不确定因素实现而对应的运行调度安排,降低年总费用,保证系统安全稳定运行,实现经济性和可操作性综合最优。     

热电厂集中供热——过热蒸汽在轮胎工业中的应用

阐述了热电厂集中供热提供过热蒸汽在轮胎工业中的应用,根据轮胎双模定型硫化机的硫化工艺要求,实际采用内温和外温的供汽参数和供汽方案,以及过热蒸汽减温、减压装置控制原理。     

热电厂集中供热——过热蒸汽在轮胎工业中的应用

阐述了热电厂集中供热提供过热蒸汽在轮胎工业中的应用,根据轮胎双模定型硫化机的硫化工艺要求,实际采用内温和外温的供汽参数和供汽方案,以及过热蒸汽减温、减压装置控制原理。     

国产大化肥装置减温减压阀运行故障分析

某化肥生产装置作为国内首套具有自主知识产权的国产化大化肥生产装置,其蒸汽系统采用减温减压阀进行调节。在运行过程中,减温减压阀发生阀门卡涩故障,导致蒸汽系统不能稳定运行。拆检阀门分析发现,其主要问题是内部杂质和开车过程中暖管不充分,造成阀体水击损坏。通过更换维修损坏部件,优化暖管操作,保证了减温减压阀的正常运行,稳定了蒸汽系统。     

考虑多类型不确定性的蒸汽动力系统运行优化

针对蒸汽动力系统中包含的多类型不确定性,根据基于时间表达、基于发生概率表达和基于集合表达划分不确定变量.多周期离散化操作解决基于时间表达的不确定变量;在各个周期内,耦合机会约束规划和鲁棒优化解决基于发生概率表达和基于集合表达的不确定变量,建立了机会约束鲁棒优化模型.以某石化企业蒸汽动力系统实例为背景,将该模型和传统模型...     

蒸汽减温减压过程中能级优化分析及建议

本文以我公司某装置减温减压装置为例,对蒸汽在减温减压过程中的能级进行分析,计算"火用"(yong)损失,分析采用螺杆膨胀发电机组进行发电,实现能的优化利益。     

煤制气蒸汽动力系统多周期模拟与优化

蒸汽动力系统是煤化工的重要组成部分,为工艺提供蒸汽和动力.针对煤制气动力系统存在的能源浪费和经济亏损的问题,建立了锅炉、汽轮机、减温减压器和除氧器等关键设备的数学模型,以此集成得到蒸汽动力系统的数学模型.以系统运行成本为目标函数,采用某煤制气企业多周期的实际数据建立了混合整数非线性规划(MINLP)优化模型.优化后的系...     

蒸汽动力系统设计与多周期运行同步优化

蒸汽动力系统(Steam power system,SPS)是炼油企业的重要组成部分,针对炼油企业蒸汽动力系统设计与运行方案上存在的不合理方面,通过对蒸汽动力系统建立混合整数线性优化模型(MILP),改善部分系统结构、调整系统多周期运行方案,从而降低蒸汽动力系统的运行费用实现系统的优化。以某炼油企业蒸汽动力系统实为背景,对企业蒸汽动力系统的设计与多周期生产调度方案进行优化,并验证优化策略的有效性。     

半钢子午胎硫化供汽系统改造

在原有供汽系统等压运行条件下，通过合理改造，加装减温减压装置，将原系统分类内胎锅炉房高压供汽系统和老锅炉房低压供汽系统，以满足半钢子午胎对高压蒸汽的需求，达到缩短硫化时间，提高生产能力的目的。     

改进PSO算法在蒸汽动力系统多周期运行优化中的应用

为了满足石化企业工艺过程对蒸汽和电力不断变化的要求,实现企业降低成本、节能降耗的目的,必须保证蒸汽动力系统在最优的状态下运行。针对这一问题在以往研究的基础上提出了包括设备维护和启停费用的改进的混合整数线性规划模型,利用改进的PSO算法对其求解,并通过实例证明了利用该模型、使用改进的PSO算法能很快得到最优的方案,并节省了大量的运行成本。     

考虑生产成本和环境成本的蒸汽动力系统多目标运行优化

石化企业生产过程中污染性气体的排放问题日益引起人们的重视,生产过程进行用能调度运行优化时,需要兼顾节能降本和减少排放两个矛盾的优化目标。综合考虑能源设备、生产操作及大气污染物排放等因素,建立了蒸汽动力系统的多目标混合整数线性规划(MOMILP)模型,采用改进增广e-约束法对生产成本和环境成本两个目标统筹进行优化,从而获取设备燃料配比和能源分配的优化调度方案。同时,以某石化企业蒸汽动力系统实例为背景,对不同环境收费标准下的生产调度方案进行细致对比和分析,结果验证了所用优化调度模型的有效性。     

冷热电联供系统设计和运行集成优化

冷热电联供是提高能源综合利用效率的有效途径,其系统设计与运行策略通常相互耦合,因此实施联供系统的集成优化至关重要。本文同时考虑全生命周期内的投资与运行成本,提出以年度总成本最小化为优化目标,结合联供系统中燃气轮机、余热锅炉、吸收式制冷机等设备特性方程,以及针对以电定热、以热定电和混合热电三类典型运行策略,设置了冷、热和电三种负荷需求能量平衡方程,最终构建了包含固定电/热效率和动态电/热效率的联供系统设计与运行集成优化模型。所提方法应用于典型商业楼宇的冷热电联供系统优化设计,结果表明,只有通过综合运用混合热电运行策略、动态电/热效率和全年负荷特性数据,才有望获得合理可行的最优设计方案。     

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.     

蒸汽—电联合动力在水泥厂余热利用中 的分析与实践

针对许多熟料生产线的剩余余热蒸汽,设计了蒸汽—电联合动力方式,通过工业汽轮机与电动机联轴运行,实施水泥厂大型转动设备的蒸汽—电联合动力。实现了以较低的成本,扩展水泥厂余热蒸汽的利用范围,降低熟料生产线的用电量。论文对比分析余热发电与蒸汽—电联合动力的效率,结果表明,蒸汽—电联合动力有更高的效费比,更低的投资与运行费用。     

基于不确定蒸汽需求和设备故障的锅炉系统随机规划设计

公用工程系统中锅炉系统设计不仅要考虑锅炉应对发生的故障的可靠性,还要保证系统具有一定应对蒸汽需求的波动的可操作性。本研究针对满足不确定蒸汽需求和考虑设备故障的锅炉系统设计,提出基于数学规划法的设计模型：对生产过程波动引起的不确定蒸汽需求以概率表达,采用Markov模型分析锅炉故障,表达为以一定概率发生的不确定参数。优化模型采用二阶段随机规划策略对蒸汽需求不确定波动和锅炉故障实现引起的约束违背进行补偿,以降低不确定变量对目标函数和约束条件的影响。以年总费用最小为目标,建立混合整数线性模型（MILP）,实现锅炉系统配置,设备模式确定以及应对蒸汽需求波动和设备故障发生的补偿操作的优化设计。     

Optimization of integrated cogeneration power plant and desalination plant systems for a range of power and water supply requirements

Comparative economic analysis is presented which shows necessity of integrated power and desalination plants optimization rather than separate optimization of power generating and desalination units. This paper introduces:- Calculational procedure and resulting curves for cogeneration plant selection for a range of power and steam demands.- Conceptual procedure for integrated power plant and desalination plant system optimization.- Results of comparative economic analysis of integrated power/ desalination plant optimization as compared with separate power plant and desalination plant optimization.     

Analysis of water and power costs by various methods,based on Jeddah IV

The Jeddah IV Power and Desalination Plant is the biggest, dual-purpose plant in the world. Moreover, it is perhaps the first plant of this kind for which authentic cost and operational data are available. As such, it provides a reliable means of assessing the present status of desalination technology and its influence on the cost of power and water.The well-known theoretical methods of cost allocation are used in deriving the product cost from the Jeddah IV plant. The influence of local factors and contractual constraints is discussed. Extrapolations are made to determine the projected cost of water on similar plants but with different performance ratios. Recommendations are made on cost optimization and the most favourable combination for dual-purpose power/desalination plants based on steam turbines and MSF process.     

Technical and economic analysis for the integration of small reverse osmosis desalination plants into MAST gas turbine cycles for power generation

A technical and economic analysis concerning the integration of small reverse osmosis (RO) desalination plants into mixed air steam turbine (MAST) technologies for power generation was carried out. The simulation tool used is the computer aid reverse osmosis calculations optimization algorithm. This user-friendly software takes into account the capital cost, fuel cost and operation and maintenance requirements of each candidate RO desalination plan scheme and calculates the least-cost configuration. The results indicate that the integration of a RO desalination plant into MAST gas turbines has a minor effect on the final operating cost of the power plant.