Science: The Environment:

A New Type of Small and High Performance Heat Sources for Environmental Solutions

By Dr. Keiji Taniguchi, Fukui University; Dr. Tsugio Matsuura, Fukui Industrial Technology Center;
and Dr. Sadakazu Watanabe, Fukui University

 

1. Introduction
Environmental contamination generated by wastes has brought a number of serious problems. Technically, there are two types of methods used for processing these wastes: organic processing and heat processing. Particularly in the processing of solid wastes, dioxins (poisonous material) generated by the low temperature burning of solid wastes and medical wastes present a serious environmental problem to nations throughout the world. In order to solve these problems, a specially developed high temperature heat-source is required. We show here the new structure of a simple and efficient arc-plasma heat source operated by the multi-phase power source that is converted from commercial three-phase alternating currents.

 

2. Method

The schematic diagram for the arc-plasma generation is illustrated in Fig. 1. The power source of multi-phase alternating currents that is converted from the three-phase commercial power supply is used for generating the arc-plasma. From our target, using two sets of electrodes (each set consisting of six electrodes) we can select either the two-dimensional arrangement constructed by six or twelve electrodes, or the three-dimensional arrangement constructed by both sets of electrodes as the operation mode of arc-plasma generation.

 

3. Estimation of minimum temperature

The energy radiated from the arc-plasma is measured by using a spectrometer. Fig. 2 shows an example of the spectral distribution which consists of two major parts: the black body radiation and the line spectral radiation. From the peak value of the black body radiation, we can estimate the minimum temperature value in the arc-plasma space. From Fig. 2, the wavelength λ_m of the peak point is approximately 570 (nm). Therefore, the temperature in the arc-plasma space is approximately 5000 (K) (this value was calculated by the formula:). The effect for the line spectral radiation shown in Fig. 2 is not contained here at all. Therefore, this is the minimum value of temperature.

Fig. 1. Schematic diagram for the arc-plasma generation

 

 

 

4. Examples of the processed results

The first example is that of incinerated Municipal Solid Waste (MSW) and the processed results are shown in Fig. 3(a) and Fig. 3(b), respectively. In example 2, the medical waste material (used syringes) and the processed result (melted needles and casings, which can then be recycled as raw material) are also shown in Fig. 4(a) and Fig. 4(b), respectively.

 

5. Conclusion

This method can easily obtain a significantly higher and wider temperature space as compared with traditional methods. This method is particularly useful for processing solid wastes which contain poisonous materials.

 

 

 

Fig. 2 Spectral distribution radiated from the arc-plasma space

(This illustrates the case of employing six electrodes.  Current is 200A/phase. Voltage between phases is about 45(v))

 

 

 

 

 

 

 

Example 1: Municipal Solid Waste

 

              

Fig. 3(a) Incinerated MSW             Fig. 3(b) Processed result

 

 

 

Example 2: Medical Waste

 

         

Fig. 4(a) Syringes             Fig. 4(b) Processed result

Dr. Keiji Taniguchi is a member of the Editorial Advisory Board for Bibliotheque: World Wide/BWW Publishers and the BWW Society; he is currently Honorary Professor at Japan's Fukai University and at Xi'an University of Technology in Xi'an China.