水煤浆气化装置的腐蚀与防护

某公司的水煤浆气化装置在运行过程中暴露出很多的腐蚀、结垢和堵塞问题.对现场装置进行腐蚀调研,通过工艺流程、腐蚀性介质以及腐蚀流程分析,判断腐蚀类型和腐蚀规律.从选材推荐和腐蚀监测检测方面提出了防护对策,抑制了设备和管道腐蚀,保障了装置的长周期安全稳定运行.     

多喷嘴对置式水煤浆气化技术应用总结

总结了多喷嘴对置式水煤浆气化炉从开车至今近3年的运行情况。通过加强对原料煤的管理、优化气化炉操作条件,为气化炉的长周期稳定运行奠定了基础。气化装置运行200d后,气体洗涤设备（水洗塔）、黑水处理设备（蒸发热水塔）等主要设备内件无结垢现象,仅在填料表面有轻微结垢,不影响继续生产。介绍了气化装置在运行过程中出现的闪蒸角阀后管线磨损以及运转设备中存在的问题,分析其原因并采取相应的技改措施,取得了满意的效果。     

大数据分析优化变换预热器运行参数

大唐呼伦贝尔化肥有限公司建设了世界上首套以褐煤水煤浆为气化源头的煤化工项目,开车以后出现一系列问题,其中变换工段原料气预热器的结垢堵塞最为严重,制约着整个项目的长周期稳定运行,给公司生产经营带来了损失。本文采用"大数据分析"的理念,对预热器某一运行周期内的相关操作运行参数进行系统分析,筛选出导致积灰结垢的操作参数,并进一步优化,为后续装置的运行提供指导。     

裂解气压缩机段间换热器堵塞在线处理

随着炼化一体化发展,乙烯装置均朝着长周期、高负荷方向努力,原料轻质化促使压缩机结垢和换热器堵塞的问题越来越突出,有效控制、解决压缩机结垢和换热器堵塞问题,是延长乙烯装置长周期运行的关键之一。四川乙烯装置2018年6月大检修开车运行后,仅1 a就出现裂解气压缩机段间换热器堵塞情况,严重影响装置的长周期运行。通过分析原因,采取增加段间分散剂、变更洗油组成、增设换热器洗油注入线等措施解决了问题,达到了预期效果,同时乙烯装置避免1次10 d的非计划停工带来的损失。     

热电厂脱硫系统工艺用水分析

通过分析燃煤电厂氨法脱硫工艺补水分析,使用新鲜水、循环水等作为工艺水带入的钙镁离子在脱硫系统内循环,不断被浓缩,导致脱硫系统局部存在结垢、堵塞和磨损,影响脱硫装置的稳定运行,设备运行可靠性低,成为制约脱硫装置长周期运行的瓶颈问题之一,通过优化用水,实现热电厂脱硫系统稳定运行环保达标的目标。     

水煤浆气化工艺中的问题与改进

针对水煤浆气化装置在设计中存在的问题,经过一年多的系统运行和经验摸索,对制浆系统、气化系统、灰水处理系统、联锁系统进行了多项技术改造,保证了装置长周期安全稳定运行,目前气化炉负荷可以达到110%,双炉取得140 d以上的连续运行长周期。     

防止设备结垢延长乙烯装置运行周期

设备结垢堵塞问题已成为乙烯装置长周期运转的难点。笔者重点论述了急冷油塔和冷箱的结垢问题及防范措施。     

多喷嘴煤气化装置长周期运行影响因素分析

介绍多喷嘴对置式水煤浆气化装置稳定运行的影响因素,针对煤质、阀门管道磨漏堵塞和煤浆给料泵运行周期的问题进行分析并提出相应的解决措施,确保气化炉的长周期稳定运行。     

GSP粉煤气化装置运行分析

根据GSP粉煤气化装置开车以来在运行中出现的问题，有待进一步解决的主要问题是气化工艺生产过程中产生的粗合成气尘含量高，导致变换原料气换热器和保护床堵塞，文丘里系统管道、阀门、设备、机泵等经常性磨损、堵塞，严重影响装置长周期运行。     

多喷嘴对置式水煤浆加压气化装置水系统处理及运行建议

概述多喷嘴对置式水煤浆加压气化工艺以及水质特点，阐述煤气化系统水处理机理。根据近7年的实际运行情况，分析了煤气化装置水系统结垢、絮凝的影响因素，提出煤气化装置长周期稳定运行的建议。     

A Review of Ozone Generating Facilities in Some U.S. Water and Wastewater Treatment Plants

In previous years, the start-up and operation of ozone systems at U.S. municipal water and wastewater treatment facilities has resulted in numerous problems. Some of these problems were of such a magnitude that the operating agency decided to abandon the ozone system. In other cases, the system is operating and the problems are resolved. An investigation of 11 U.S. facilities was conducted to determine what problems were experienced and how the problems were resolved.     

Time representations and mathematical models for process scheduling problems

During the last 15 years, many mathematical models have been developed in order to solve process operation scheduling problems, using discrete or continuous-time representations. In this paper, we present a unified representation and modeling approach for process scheduling problems. Four different time representations are presented with corresponding strengthened formulations that rely on exploiting the non-overlapping graph structure of these problems through maximum cliques and bicliques. These formulations are compared, and applied to single-stage and multi-stage batch scheduling problems, as well as crude-oil operations scheduling problems. We introduce three solution methods that can be used to achieve global optimality or obtain near-optimal solutions depending on the stopping criterion used. Computational results show that the multi-operation sequencing time representation is superior to the others as it allows efficient symmetry-breaking and requires fewer priority-slots, thus leading to smaller model sizes.     

沼气脱硫系统存在的问题及解决措施

简单介绍了某公司沼气脱硫系统在生产初期出现的一些问题,通过对这些问题的分析和判断,提出了解决问题的方案.通过多次试验并与原来方法对比,提出的新方法在沼气脱硫系统生产中是成功的、令人满意的.     

Solving mixed integer nonlinear programming problems with line-up competition algorithm

Line-up competition algorithm (LCA), a global optimization algorithm proposed recently, is applied to the solution of mixed integer nonlinear programming (MINLP) problems. Through using alternative schemes to handle integer variables, the algorithm reported previously for solving NLP problems can be extended expediently to the solution of MINLP problems. The performance of the LCA is tested with several non-convex MINLP problems published in the literature, including the optimal design of multi-product batch chemical processes and the location-allocation problem. Testing shows that the LCA algorithm is efficient and robust in the solution of MINLP problems.     

A general framework for process scheduling

Existing methods for process scheduling can be broadly classified as network‐based or sequential. The former are used to address problems where different batches of the same or different tasks are freely mixed or split, whereas the latter are used to address problems where batch mixing/splitting is not allowed. A framework is proposed that allows us to: (1) express scheduling problems in facilities that consist of network and sequential, as well as continuous subsystems, (2) formulate mixed‐integer programming (MIP) scheduling models for such problems, and (3) solve the resulting MIP formulations effectively. The proposed framework bridges the gap between network and sequential approaches, thereby addressing the major formulation challenge in the area of process scheduling, namely, the development of a framework that can be used to address a wide spectrum of problems. © 2010 American Institute of Chemical Engineers AIChE J, 57: 695–710, 2011     

A global optimization algorithm (GOP) for certain classes of nonconvex NLPs—II. Application of theory and test problems

In Part I (Floudas and Visweswaran, Computers chem. Engng 14, 1397, 1990), a deterministic global optimization approach was proposed for solving certain classes of nonconvex optimization problems. An algorithm, GOP, was presented for the rigorous solution of the problem through a series of primal and relaxed dual problems until the upper and lower bounds from these problems converged to an -global optimum. In this paper, theoretical results are presented for several classes of mathematical programming problems that include: (i) the general quadratic programming problem; (ii) quadratic programming problems with quadratic constraints; (iii) pooling and blending problems; and (iv) unconstrained and constrained optimization problems with polynomial terms in the objective function and/or constraints. For each class, a few examples are presented illustrating the approach.     

An Efficient Calculation of Multidimensional Freeze-Drying Problems Using Fixed Grid Method

Abstract

A calculation procedure based on a fixed grid method streamlined for multidimensional freeze-drying problems was developed, considering coupled heat and mass transfer, sublimation of ice, and motion of ice front. Efficiency of the fixed grid calculation in solving one- and two-dimensional freeze-drying problems was evaluated by comparing its accuracy and calculation cost with those of a conventional moving grid calculation. The numerical investigation showed that the fixed grid method can produce accurate results comparable to those obtained by the moving grid method, with almost equal calculation cost in case of one-dimensional freeze-drying problems. But the fixed grid method required about 70% more computation time than the moving grid method in case of two-dimensional freeze-drying problems. It is thought that the fixed grid method may be advantageous over conventional moving grid methods when freeze-drying problems involving cumbersome moving interface geometries have to be considered.     

APPLICATION OF THE TRANSFORM-ITERATIVE METHOD TO NONLINEAR CONCENTRATION BOUNDARY VALUE PROBLEMS

In this paper we present a “somewhat” new method that treats nonlinear concentration related boundary value problems, among other problems. The method uses a general convolution product to transform the nonlinear term, then it iterates with successive division inside the integral to arrive at the approximate solution. It will also include an explanation to the apparent success of what was recently termed “novel transform method” for such nonlinear problems, as being a very special case. As such, it represents the first mathematical basis of any kind, that would offer a reason for the limited success of the recent “novel” method. The present method is illustrated here, for a porous catalyst slab with an outline for other geometries and different non-linearities. The numerical results agree very well with the known exact results of these problems, and other problems in different fields.     

Suboptimal control through model reduction

There has been a growing interest in control strategies that optimize a given performance criterion to improve process efficiencies. Optimal control techniques, such as LQP, have been available but did not find much acceptance in process industries because of certain problems that are involved in their application. In this paper an approach is presented which alleviates these problems. Simulation results show that the proposed approach works well for servo and regulatory control problems.     

从整流角度分析离子膜电解槽运行中发生的问题

从整流角度探讨离子膜电解槽运行中停电的原因并对电解槽常发生的问题加以归类,从中可看出哪些与整流有关,哪些与整流无关;提出了对电解槽所发生的问题应作具体分析并客观对待的观点。