Yan Keping

Current Density and Efficiency of a Novel Lab ESP for Fine Particles Collection

Understanding the current density will help to improve the ESP’s energy consumption and the collection efficiency of fine particles. In this study, corona current density and dust collection efficiency were studied with a laboratory ESP. Dust collection experiments were performed with various electrode distances from 22 mm to 330 mm, and also with a single discharge electrode. Discharge for 40 to 50 seconds with 46 kV voltage, 160 g/m3 inlet dust concentration and 700 m3/h flow rate. Ash layer thickness collected on the plate is about 4 mm on average. We observed that the total currents are greatly influenced by the plate-plate gap and electrode distance. The maximum total current was obtained in the 132 mm discharge electrode distance (about half of the plate-plate gap width). The operating voltage range of positive corona is only about half that of the negative corona. Dust layer Accumulation on the plate reduced the total collection current, and increased the spark voltage about 4 kV with 4 mm dust thickness. Increase in the discharge electrode number of the outlet field can improve fine particles collection efficiency.

Industrial Applications of a New AVC for Upgrading ESP to Save Energy and Improve Efficiency

This paper reports one demonstration investigation on one new automatic voltage controller (AVC) named ZH2005 to improve dust collection efficiency and save energy consumption. Experiments were performed with a 200 MW coal-fired boiler owned by Huaneng Beijing Cogeneration Co., Ltd. Energization methods, such as simple-pulsing, spark-rate control, intermittent energization and ZH2005 method, were adopted for evaluation of both dust emission and energy consumption. After almost one-year utilization, we conclude that the ZH2005 can keep outlet dust emission to be below 20mg/Nm3 and/or a total dust reduction of about 120T per year with an energy-saving of about 70% or 1260 MWh.

Industrial Applications of Three-phase T/R for Upgrading ESP Performance

This paper reports one of our recent ESP upgrading activities. It was performed with a 600 MW coal fired boiler equipped with a four-channels and four-fields ESP. The dust collection efficiency was around 98.69% and the emission was in the range of 200 mg/m3–300 mg/m3. The upgrading include replacing the four traditional single-phase T/Rs used for inlet fields with four three-phase ones. The new HV system has been in operation for over one year. Dust emission keeps to be below 200 mg/m3 with more than 400 kW energy saving.

Streamer Corona Plasmas and NO Removal

This paper reports experimental studies on the discharge modes with AC/DC and DC power sources and different electrode configurations. Very uniform streamer coronas can be generated by using AC/DC source. The energy cost for NO oxidation in air is about 30 eV/NO.

Experimental Investigation on Styrene Emission with a 1000m3/h Plasma System

This paper reports experimental investigations on plasma-induced styrene emission abatement in air at room temperature (24±2°C) and pressure. Tests were performed with a 1000 m3/h plasma system under DC corona discharge. It is observed that styrene destruction in DC glow discharge is negligible in contrast to streamer corona. When relative humidity (RH) is in the range of 30%–80%, the energy consumption for styrene decomposition rises with RH value. The energy coefficient β value becomes larger with increasing either RH or the initial styrene concentration for RH in 30%–80% and the concentrations within 90 ppm–1000 ppm, respectively. With regards to those dependence sensitivity, the lower the concentration, the more sensitive to the RH value. Under optimal condition (100 ppm initial concentration, 35% RH), the β value is 18.73 J/L.