Design and feasibility verification of regenerative system of electric thermal storage boiler for peak shaving in summer in power plant

During the heating period, the thermal storage electric boiler helps the thermal power units to participate in the deep peak regulation by converting the electric energy into heat energy for heating users, but in the non-heating period, the thermal storage electric boiler can not operate because there is no heat user, as a result, the thermal storage electric boiler is shut down in summer, and can not assist the thermal power unit to participate in the deep peak regulation. Therefore, this paper designs an electric thermal storage boiler regenerative system for peak shaving in summer. In this regenerative system, electric boiler is used to heat circulating water in heating period, and electric boiler is used to heat condensed water in non-heating period, and in the non-heating period, the number of low-pressure heaters can be adjusted according to the load and heat storage capacity of the units, so that the electric boiler can assist the thermal power units to participate in the deep peak regulation throughout the year, taking a 350MW unit with 70MW regenerative electric boiler as an example, the heat exchange capacity is calculated to verify the feasibility of the regenerative system. In this paper, a new method of heating condensate by regenerative electric boiler in non-heating period is proposed to solve the problem that the new energy can not be used and the energy is wasted in summer.

Analysis of the advanced oxygenate water level control scheme of the engineering supercritical unit

The oxygenate water level is an important adjustment parameter in the operation of the fire generator set, and the water level may result in the safety of the water pump. The high water level will not only affect the oxygen effect, but it is also possible to cause the water shot to the steam turbine to cause a water shot or give the water tank full water, oxygenate vibration, drain and vapor with water. When the load is low (generally 35% rated load), the oxygenate water level is controlled by large and small valve, condensate pump variable frequency control condensed water drum pressure. When the unit load is high (greater than 35 rated load), the oxygenate water level is controlled by the condensed water pump, the large valve and small valve controls condensed water drum pressure.

Effect of flow rate on the corrosion behaviour of API 5L X80 steel in water-saturated supercritical CO2 environments

The effect of the water-saturated supercritical carbon dioxide flow rate on the corrosion behaviour of API 5L X80 steel at a temperature of 35 oC and pressure of 80 bar was investigated. Tests were carried out with the samples attached to a rotating shaft inside an autoclave. Results indicate that increasing the scCO2 flow rate had no significant influence on the general/localized corrosion rate under the various dynamic conditions considered. The average general corrosion rate was 0.064 mm/year, while the average measured pitting penetration rates were one order of magnitude higher. The size of the corrosion features on the surface of the samples, which were believed to provide an indication as to the size of the condensed water droplets, were much smaller than the calculated critical droplet size needed to be displaced by the flow, supporting the theory as to why flow rate had little effect on the corrosion response.

Laboratory tests of a prototypical user-centric radiant cooling solution

Radiant cooling systems are being increasingly promoted because of their energy efficient operation as well as their potential to improve occupants’ thermal comfort due to a draft-free cooling process. This paper focuses on a specific radiant cooling approach, which was introduced in previous contributions. This approach involves the positioning of relatively small-sized vertical radiant panels in the close proximity to occupants. Furthermore, the panels incorporate drainage systems or collection elements to accommodate, if needed, water vapour condensation. Consequently, the surface temperature of the radiant panels does not need to stay above the dew point temperature. We present the outcome of a preliminary experimental investigation of such a personal radiant cooling system. In this context, prototypical radiant panels were installed in a laboratory and multiple experiments were conducted. The uniformity level of the panels’ surface temperature distribution was documented. Moreover, near-panel air flow velocities were measured at several positions. Likewise, the formation of condensed water on panels was observed for different panel surface temperatures, room temperatures, and room humidity levels. The results of the preliminary laboratory investigation do not point to any risk of draft or turbulence discomfort.

Experimental Study of the Air Side Performance of Fin-and-Tube Heat Exchanger with Different Fin Material in Dehumidifying Conditions

Under dehumidifying conditions, the condensed water will directly affect the heat transfer and resistance characteristics of a fin-and-tube heat exchanger. The geometrical form of condensed water on fin surfaces of three different fin materials (i.e., copper fin, aluminum fin, and aluminum fin with hydrophilic layer) in a fin-and-circular-tube heat exchanger was experimentally studied in this paper. The effect of the three different fin materials on heat transfer and friction performance of the heat exchanger was researched, too. The results show that the condensation state on the surface of copper fin and aluminum fin are dropwise condensation. The condensation state on the surface of the aluminum fin with the hydrophilic layer is film condensation. For the three different material fins, increasing the air velocity (ua,in) and relative humidity (RHin) of the inlet air can enhance the heat transfer of the heat exchanger. Friction factor (f) of the three different material fins decreases with the increase of ua,in, however, increases with the increase of RHin. At the same ua,in or RHin, Nusselt number (Nu) of the copper fin heat exchanger is the largest and Nu of the aluminum fin with hydrophilic layer is the smallest, f of the aluminum fin heat exchanger is the largest and f of the aluminum fin with hydrophilic layer is the smallest. Under the identical pumping power constrain, the comprehensive heat transfer performance of the copper fin heat exchanger is the best for the studied cases.

Nanoscale Wetting of Single Viruses

The epidemic spread of many viral infections is mediated by the environmental conditions and influenced by the ambient humidity. Single virus particles have been mainly visualized by atomic force microscopy (AFM) in liquid conditions, where the effect of the relative humidity on virus topography and surface cannot be systematically assessed. In this work, we employed multi-frequency AFM, simultaneously with standard topography imaging, to study the nanoscale wetting of individual Tobacco Mosaic virions (TMV) from ambient relative humidity to water condensation (RH > 100%). We recorded amplitude and phase vs. distance curves (APD curves) on top of single virions at various RH and converted them into force vs. distance curves. The high sensitivity of multifrequency AFM to visualize condensed water and sub-micrometer droplets, filling gaps between individual TMV particles at RH > 100%, is demonstrated. Dynamic force spectroscopy allows detecting a thin water layer of thickness ⁓1 nm, adsorbed on the outer surface of single TMV particles at RH < 60%.

Pressure Vessel Mechanical Design Case study for 10 kg/cm² Pressure and 179 C Temperature

Pressure vessel is a closed tube that holds pressure, both internal pressure and external pressure. This pressure vessel is designed to function as a reservoir for condensate or condensed water and convert it into steam or hot steam. This article discusses the design of a pressure vessel for a pressure of about 10 kg/cm² and a design temperature of 179oC. In the design of this pressure vessel, it includes determining the material to be used in the design, determining the allowable stress of each material used, determining the cylinder wall thickness, cylinder head or cover wall thickness, nozzle wall thickness, determining the maximum allowable working pressure limit. or maximum allowable working pressure and testing after the pressure vessel is finished, namely the hydrostatic test method. The design has been successfully carried out according to the provisions. Bejana tekan atau pressure vessel adalah suatu tabung tertutup penampung tekanan, baik tekanan dari dalam maupun tekanan dari luar bejana. Bejana tekan yang ini dirancang berfungsi sebagai penampung condensate atau air kondensasi dan mengubahnya menjadi steam atau uap panas. Pada artikel ini dibahas perancangan pressure vessel untuk tekanan sekitar 10 kg/cm² dan suhu rancang 179oC. Dalam perancangan bejana tekan ini meliputi pemilihan material yang akan digunakan dalam perancangan, menentukan tegangan yang diijinkan atau allowable stress dari setiap material yang digunakan, menentuan tebal dinding silinder, tebal dinding head atau penutup silinder, tebal dinding nozzle, menentuan batas tekanan kerja maksimum yang diijinkan atau maximum allowable working pressure dan pengujian setelah bejana tekan jadi yaitu dengan metode hydrostatic test. Dalam artikel ini perancangan secara numeris telah berhasil dilakukan dengan baik sesuai ketentuan.