智能控制在轧钢加热炉上的节能应用

轧钢机是钢铁行业的重要装备,其节能降耗一直以来都是我国发展过程中不可缺少的部分,因为经济全球化和新能源技术不断涌现及推广,传统电控加热设备已然无法满足当前生产工艺要求,因此智能化、高效化控制在这一背景下应运而生并得到广泛应用。首先从优化控制系统在棒材加热炉应用设计方案进行分析;其次对加热炉各回路优化控制方案设计展开介绍,比如炉膛温度控制回路、炉膛压力控制回路、烟温控制回路、炉膛压力与烟温协调控制设计和加热炉安全运行控制功能设计;最后探究了加热炉经济运行统计与考核功能。     

京唐热轧2250mm加热炉烟气余热回收控制系统

结合京唐热轧2 250 mm加热炉烟气余热回收控制系统的调试过程,分析了增设烟气余热回收蒸发器后对原有汽化冷却控制系统及炉膛压力控制系统的影响,并最终通过调整仪表设备参数、升级老化仪表设备、优化控制策略,克服了在烟气量剧烈变化时对加热炉炉膛压力控制、汽包液位控制造成的波动,实现了全自动控制。     

蓄热式加热炉炉压控制方式的研究

针对加热炉在进行蓄热式改造过程中,炉膛压力较大,炉门冒火现象严重的问题,分析原有压力控制系统及流量控制系统对炉膛压力产生的影响.找出在自动控制系统中存在的问题,并进一步提出改进措施.     

模糊控制在加热炉炉膛压力控制中的应用

文章介绍了连续式加热炉炉膛压力控制在加热炉生产控制中的实际意义及加热炉炉膛压力的检测方法和控制方法。因为炉门经常开关,会引起炉膛压力频繁波动,而常规PID的调节方式抗干扰能力不强,在测量值经常变化的情况下易产生振荡,不能进行有效的控制。模糊控制正好有收敛速度快、超调小且抗干扰能力强的特点,最适宜用来控制炉膛压力。     

加热炉炉膛压力自动控制的方法及可实现条件

论述了加热炉炉膛压力控制的作用、控制方法，分析了炉膛压力控制失灵问题的原因以及解决的方法，给出了实现加热炉炉膛压力自动控制的条件。     

蓄热式连续加热炉炉膛压力问题研究

蓄热式连续加热炉炉膛压力偏高且波动频繁,在一定程度上影响着炉子的单位燃耗和使用寿命.对比换热式、蓄热式两类加热炉在结构及操作上的不同,得知炉内气体流动状况是影响炉膛压力的主要因素.运用气体流动相关知识,建立炉气流动模型,研究沿炉宽方向上的压力分布.结果表明,沿炉宽方向上炉膛压力高于空、煤气喷口压力和排烟口压力;流量增加时,炉膛压力明显升高;蓄热式炉的宽度尺寸超出允许范围后,压力问题突出.     

优化H型钢加热炉热工制度的尝试

马钢在热工调查中发现,H型钢在加热炉运行中存在加热及均热段炉膛温差较大问题,不利于钢坯均匀加热。通过增减加热炉计算机远程区域热负荷来改善炉温的不均衡趋势,以及采取单个烧嘴直接手动调节来减小局部温差的热工调试,缩小了炉膛和钢坯加热表面的温差,优化效果明显;并提出了引进热工智能控制技术,研究钢坯热装温度与加热负荷的关系,开展降低出钢温度试验研究的优化热工制度的思路。     

无缝钢管厂热轧线加热炉控制系统

介绍了无缝钢管厂热轧线环形加热炉和步进加热炉控制系统的组成及功能，重点叙述了环形炉炉膛压力控制自学习功能及其实现。运行结果：温度控制精度达±５ ℃，炉压控制准确度达±３ Ｐａ 。     

降低棒材蓄热式加热炉炉膛压力探索与实践

安阳钢铁周口钢铁公司普通棒材和高速棒材生产线的两座蓄热式加热炉在投产之后存在炉膛压力过高的问题,经过分析找到了造成炉压过高的原因,针对性的采取了一系列有效措施,解决了两座蓄热式加热炉炉膛压力过高的问题,取得了良好效果。     

连续重整圆筒炉低NO_x燃烧器升级改造应用

云南石化240万t/a连续重整装置共设置5台圆筒炉,在装置投料试车初期出现炉膛负压大幅波动、炉膛中上部存在烟气二次燃烧、燃烧器频繁脱火熄灭等现象,直接影响加热炉稳定运行。通过对低NO_x燃烧器增设中心稳焰枪、更换新型长明灯的技术改造后,加热炉运行工况得到明显改善,炉膛温度降低,炉膛负压和氧含量控制稳定,消除炉膛内烟气二次燃烧,解决燃烧器频繁脱火熄灭等问题,同时有效降低过剩空气系数,节约燃料并提高加热炉热效率、降低装置综合能耗,且烟气中NO_x含量远低于环保排放限值。     

Dynamic pressure in mould flux channel during mould non-sinusoidal oscillation

Abstract

Based on the lubrication theory of mould flux, a mathematical model of dynamic pressure in mould flux channel was developed, and the distribution of dynamic pressure and its variation during non-sinusoidal oscillation were investigated. The effects of casting speed and non-sinusoidal oscillation parameters, including the degree of non-sinusoidal operation (non-sinusoidal factor), amplitude and frequency of oscillation on the dynamic pressure in the mould flux channel, were studied. The results indicate that the maximum negative pressure is decreased, and the maximum positive pressure is increased with increasing non-sinusoidal factor. The optimum value of non-sinusoidal factor is ～0·2. With increasing amplitude and frequency of oscillation, both the negative and positive pressure are increased; moreover, the increment of positive pressure is obviously greater than that of negative pressure; especially when the oscillation frequency is increased, the increment of negative pressure is very little. When the casting speed is enhanced, the negative pressure is increased, but the positive pressure is decreased. Therefore, if the casting speed is increased, the oscillation amplitude needs to be increased, as well as the oscillation frequency needs to be decreased properly. With these adjustments, the positive pressure in mould flux channel is nearly unchanged. The actions of strand demoulding and cracks welding are kept effective. Moreover, the negative pressure in mould flux channel is increased properly, which causes the flux consumption to increase, so the mould lubrication is improved. Finally, the strand surface quality is improved greatly, and breakout can be avoided. The applicability of the optimised non-sinusoidal oscillation parameters for the two kinds of casting speed has been proven by industrial practice.     

风化壳淋积型稀土矿原地浸矿负压收液研究

为了探求风化壳淋积型稀土矿原地浸取工艺中负压收液的可能性及其效果,通过浸矿剂渗透规律及负压收液机理的研究,对负压收液影响因素及边界范围、负压收液试验方法、负压值与收液率的关系、负压收液工艺及其抽取方式进行了探究.优化了收液方式和条件,得出了收液率与负压值基本上呈线性关系,最佳的抽液方式为停机时间10 min,开机时间50 min,三孔联抽,负压值维持在2.66×104Pa以上.随后进行了万吨级矿块工业试验,以进一步验证优化条件,获得了理想的试验结果及技术经济指标,其中REO浸取率达77.5%.     

Mechanism of production of intestinal secretion by negative luminal pressure

The relationships between luminal hydrostatic pressure and fluid transport by dog jejunum in vivo studied as a sheet in the Wells clamp were compared with quantitative predictions from a model proposed for the mechanism of the secretion produced by elevated venous pressure. According to the model, the secretion produced by increasing venous pressure and the secretion produced by negative luminal pressure are both passive filtrates contingent on a transepithelial pressure of a few centimeters of H2O. We consider that the agreement between the observed and predicted responses to luminal pressure provides strong support for the model. In particular, a) the observations displayed a predicted gross asymmetry in rates of fluid transfer with isotonic fluids depending on whether the luminal pressure was positive or negative; b) the observed magnitude of the negative luminal pressure required for the onset of secretion agreed with predictions; and c) the secretion contained significant amounts of protein at about 25% of the plasma concentration.     

连铸保护渣道动态压力计算模型及影响因素

通过建立保护渣道压力计算模型,研究了保护渣道压力随结晶器振动的周期性变化规律以及保护渣道形状参数、连铸工艺参数和保护渣黏度对渣道压力的影响.结果表明:结晶器达到最大上振速度和最大下振速度时,渣道压力分别达到最大负压和最大正压;保护渣道形状参数对渣道压力有重要影响,渣道入口宽度和出口宽度增加,渣道正负压力都明显下降,而渣道长度增加,渣道正负压力最大值都增加;拉坯速度与结晶器振动速度都影响渣道压力,拉坯速度增加,渣道最大负压增加,而最大正压减小;结晶器振动速度和保护渣黏度增加,使渣道最大正负压力都增加.     

Effects of negative pressure assisted ventilation on dyspnoeic sensation and breathing pattern

Although negative pressure assisted ventilation with an assist-control mode may have a potential therapeutic role in the treatment of severe dyspnoea, the effects of negative pressure assisted ventilation with the assist-control mode on dyspnoea and breathing patterns have not been examined. We examined the effects of negative pressure assisted ventilation with the assist-control mode on dyspnoea and breathing patterns produced by a combination of resistive loading and hypercapnia in nine healthy subjects breathing spontaneously. Subjects were asked to rate their sensation of respiratory discomfort using a visual analogue scale. Negative pressure assisted ventilation caused a significant reduction in sensation of respiratory discomfort from a visual analogue scale score of 74 (55-91) (median (range)) before negative pressure assisted ventilation to 34 (15-53) during negative pressure assisted ventilation (p<0.01). During negative pressure assisted ventilation, there were significant changes in breathing patterns characterized by an increase in tidal volume and a decrease in respiratory frequency, while neither minute ventilation nor end-tidal carbon dioxide tension changed. Our results indicate that negative pressure assisted ventilation with the assist-control mode is effective in relief of dyspnoea and that negative pressure assisted ventilation influences the control of breathing to minimize respiratory discomfort.     

负压式加氯机在新钢公司的应用

简述了负压式加氯机的工作原理及特点，使用该机在本厂对水的处理，使水质明显得到改善，水处理成本降低，取得了较好的经济效益和社会效益。     

Genetic predisposition to hypertension facilitates blood pressure elevation in hemodialysis patients treated with erythropoietin

PURPOSE: This study investigated the hypothesis that a genetic predisposition to hypertension is involved in the etiology of the elevation in blood pressure induced by human recombinant erythropoietin (rHuEPO). PATIENTS AND METHODS: Blood pressure changes after 10 weeks of treatment with rHuEPO were compared between 26 patients with a positive family history of hypertension and 27 with a negative family history. RESULTS: Mean blood pressure was significantly increased in patients with a positive family history of hypertension (+8.8 mm Hg, p < 0.001). In contrast, the change was not significant in those whose family history was negative (+1.8 mm Hg, not significant). The mean blood pressure of 14 of 26 patients with a positive family history of hypertension increased by more than 10%, whereas such an increase occurred in only 2 of 27 patients with a negative family history (p < 0.001). The two groups were similar in terms of the total dose of rHuEPO given, the degree to which their anemia improved, and their basal blood pressures. CONCLUSION: It appears that hemodialysis patients with a positive family history of hypertension are susceptible to developing hypertension during treatment with rHuEPO.     

Water Migration Phenomenon in Concrete in Prepeak Region

An experimental and analytical study on pore-water pressure occurring in the prepeak region of concrete due to the external load is performed to investigate the mechanism of water migration in concrete. In the experiment, an apparatus is developed that can measure the pore-water pressure in concrete under fixed lateral displacement. Concrete strain, stress, and pore-water pressure are measured; the experimental parameters are the loading age and water curing period. The effects of each parameter on pore-water pressure generation are discussed. The pore-water pressure occurring in the prepeak region of concrete can be measured due to the development of a cell that is imitated to be completely fixed for the lateral displacement and undrained condition for pore water. The ratio of pore-water pressure to concrete stress is very high. The existence of the inflection point means that negative pore-water pressure exists in the voids formed by the hydration reaction during a curing period.     

Negative intraventricular diastolic pressure in patients with mitral stenosis: evidence of left ventricular diastolic suction

Left ventricular diastolic pressure was evaluated in 15 patients with mitral stenosis and 16 patients with no significant heart disease to determine if a stenotic mitral valve can cause the left ventricle to produce a negative diastolic pressure, indicative of ventricular diastolic suction. The minimal level of diastolic pressure in patients with mitral stenosis ranged between 6 and -7 mm Hg; in normal subjects it did not fall below 0. The average value of minimal diastolic pressure in patients with mitral stenosis (-2 +/- 1 mm Hg [mean +/- standard error of the mean]) was significantly lower than in patients without significant heart disease (5 +/- 1 mm Hg) (p less than 0.001). These observations indicate that the human left ventricle, in the presence of mitral stenosis, can generate a negative diastolic pressure. The presence of a negative diastolic pressure in patients with mitral stenosis suggests that the dynamics of the ventricle during diastole may contribute to the filling process.     

Classes of substance abuse relapse situations: A comparison of adolescents and adults.

Research in the process of relapse has uncovered important developmental differences in the situations that make adolescents and adults most vulnerable to relapse after substance abuse treatment. This study takes a developmental, person-centered approach to relapse by examining the latent class structure of relapse precursors in adolescents and adults. Adults (N = 160) and adolescents (N = 188) in substance abuse and psychiatric treatment were followed up to 18 months after discharge to gather detailed information about their first relapse after treatment. Both adolescents and adults exhibited a 2-class structure of relapse precursors. Adult classes were labeled social and urges situations (primary precursors: social pressure and urges; 67%) and negative and urges situations (primary precursors: negative affect and urges; 33%), while teen classes were labeled social and positive situations (primary precursors: enhancing a positive emotional state and social pressure; 69%) and complex situations (primary precursors: negative affect, negative interpersonal situations, social pressure, and urges; 31%). Findings are discussed in relation to developmental and clinical considerations in treating clients with substance use disorders and comorbid psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)