硫磺制酸装置冷热换热器冷凝酸排污管改进措施

针对硫磺制酸转化工序冷热换热器极易生成冷凝酸,腐蚀工艺管道和设备,介绍了冷凝酸排污管道的几项改进措施,如更改壳程冷凝酸排污管位置,换热器底部内衬耐酸砖,增设冷凝酸排污管及管内挡板等。这些改进措施方法简单、效果较好。

600kt/a硫黄制酸装置冷热换热器修复实践

介绍了云南磷化集团海口磷业有限公司600 kt/a硫黄制酸装置换热器的结构、泄漏的主要原因及修复实践情况。采用对局部管束进行抽管更换、对下管板局部切割更换及对管束内管喷砂清理的方法对腐蚀泄漏的换热器进行修复,取得了满意的效果。该修复方法对设备结构、换热效率和再修复性影响较小,修复耗时少,能较大限度提高设备使用价值,值得相关企业借鉴。

硫磺制酸冷热换热器串气泄漏修复新方法

介绍了硫磺制酸装置冷热换热器设备结构、泄漏原因及检修方法。冷热换热器因冷凝酸腐蚀内部换热列管,造成大量SO_3炉气串气,直接进入二次转化吸收。针对换热器泄漏,技术人员对被腐蚀的列管进行切割穿管,在管间注入耐高温耐酸混凝土,有效地降低检修费用,缩短施工周期。换热器修复后,低温热回收装置加水量及产汽量均处于正常指标,二吸塔出口气温保持在65~75℃,排放尾气ρ(SO_2)控制在240 mg/m^3以下。

一种3匹三联供冷热桥接换热器的设计

近年来,三联供在供冷供暖市场中逐渐被大众所接受,现市场上多数产品采用单系统模式,该控制方式复杂且稳定性不高,因此,本文在双系统三联供机组的基础上,设计出一种冷热桥接换热器,即一个机组的蒸发器与另一机组的冷凝器复合设计,具有节能环保,稳定性高,结构紧凑等优点,应用前景十分广阔。

Heating and Cooling Performance of Earth-Tube Heat Exchanger in a Mechanical Ventilated Farrowing House

Earth tempering of stable air has attracted great attention as a sustainable air conditioning method in pig houses. At summer time air cooling of income air strongly reduces heat stress and required ventilation rate. At winter time heating costs can be reduced. The effect of air condition using geothermal energy was investigated in a farrowing house. Underneath the foundation of the farrowing house 88 non perforated ribbed tubes （diameter： 20 cm） were piped in a depth of 1.6-2.0 m. Over a period of 12 month following data were recorded at hourly intervals and analyzed： outside air temperature, as well as air temperature in the air supply duct and in the compartments. Incoming air （supply duct） was heated up to 20 ℃ during winter time and in summer time cooled by up to 15 ℃ compared to the outside air temperature. In contrast to the outside air diurnal variation, temperature fluctuations of the incoming air were reduced by 90%. Due to cooling of the incoming air at summer time the stable inside temperature could be limited to maximal 29 ℃（maximum outside temperature was 35℃）. Earth-tube heat exchangers with non perforated ribbed tubes were very efficient for air conditioning in farrowing houses. They were a cost effective supplement for sustainable cooling and heating of farrowing houses.

A novel experimental setup with sand trunk for heat extraction of geothermal heat exchanger

A novel experimental setup was developed to study the heat extraction of geothermal heat exchanger(GHE)in different operational modes under adiabatic and isothermal boundaries.The experimental setup consists of a sand trunk,a tailored water chiller,a natural cold source unit,two water boxes containing hot water and cool water,and a data acquisition system.The experimental results indicate that the volume flow rate of the entering water is a main factor affecting the heat extraction;furthermore,the heat extraction value per meter pipe decreases gradually along the heat extraction pipe and increases with the increase of the incoming water volume flow rate.Therefore,this novel experimental setup may be helpful to further study the operation performance of GHE in different types of soil.

Condensing Heat Exchanger

The paper shows a method of designing a heat exchanger recovering heat from the condensation of water vapour contained in flue gases. A heat exchanger condenses water vapour and SO2 （sulphur dioxide） in the presence of inert gases （CO2, CO, N2, O2） contained in flue gases. A mathematical model and a sample design of a heat exchanger were presented. The heat exchange is capable of recovering from a dozen or so to several dozen percent of heat from flue gases escaping into the atmosphere. A second advantage of the heat exchanger is the possibility to reduce the emissions of SO2 considerably. Depending on the parameters, it can be even a sevenfold reduction in the emissions. The main mathematical tool used for designing the condensing heat exchanger is the Colburn-Hougen method. The authors omitted that part of the method which requires iterative calculations. The Mollier diagram was used instead.

Compact Thermosyphon Heat Exchanger for Power Electronics Cooling

The heat losses density in power electronics products follows an ever increasing trend. Nowadays they reach 200 W/cmz at chip level and 50 W/cm2 at heatsink base level. Water cooling is the most effective cooling method but unfortunately water is often undesired due to high voltages or costumer requirements. Two-phase cooling is a promising technology for electronics cooling. It allows using dielectric fluids in passive systems and still benefits from very high heat transfer coefficients. Thermosyphons are a particularly interesting technology in the field of power electronics because it is entirely passive and a simple equipment. ABB has developed a compact thermosyphon heat exchanger based on automotive technology, which uses numerous multi-port extruded tubes with capillary sized channels disposed in parallel and brazed to a heated base plate in order to achieve the desired compactness. The experimental performances of this novel power electronics cooling system are presented with R134a as a working fluid. The influence of several parameters on the performances was studied experimentally： coolant flow rate, coolant temperature, heat load and fluid filling.

Distribution optimization of circulating water in air-cooled heat exchangers for a typical indirect dry cooling system on the basis of entransy dissipation

The flow and heat transfer of air-cooled heat exchangers play important roles in the performance of indirect dry cooling systems in power plants,so it is of benefit to the design and operation of a typical indirect dry cooling system to optimize the thermo-flow characteristics of air-cooled heat exchangers.The entransy dissipation method is applied to the performance optimization of air-cooled heat exchangers in this paper.Two irreversible heat transfer processes in air-cooled heat exchangers,the heat transfer between circulating water and cooling air and the mixing of circulating water,are taken into account and analyzed by means of the entransy dissipation method.The total entransy dissipation rate,which connects the geometrical parameters of air-cooled heat exchanger sectors and the heat capacity rates of the fluids to the heat flow rate in every sector,is obtained.Based on the mathematical relation and the conditional extremum method,an optimization equation group is derived,by which the air-cooled heat exchanger with known air-side parameters is optimized,showing that the entransy dissipation based optimization approach can contribute to the distribution optimization of circulating water in air-cooled heat exchangers of a typical indirect dry cooling system.

Applicability of cement-based grout for ground heat exchanger considering heating-cooling cycles

The applicability of cement grout （or cement-based grout） has been considered as an alternative to bentonite grout commonly used to backfill closed-loop vertical ground heat exchangers. In a geothermal heat pump system, repeated heating-cooling cycles may cause adverse effects on the integrity of cement grout in the ground heat exchanger. To account for the temperature cycling effect, the strength degradation of cement grout due to temperature cycling has been examined by measuring the unconfined compression strength of cured specimens in a humidity-temperature controlling chamber with applying temperature cycles between -5℃ and 50℃. There is a tendency that the unconfined compression strength decreases with an increase in the number of temperature cycles. On the other hand, an equivalent hydraulic conductivity of a pipe-embedded cement grout specimen was evaluated by carrying out a modified flexible wall permeameter test equipped with a water circulating system to control temperature inside the pipe section. The applied operating temperature range was from 5 to 35℃. After three cycles of heating-cooling circulation, the equivalent hydraulic conductivity becomes asymptotic to a constant value, which implies there is no severe detachment of the pipe from the cement grout.