Eiichi Nishikawa

Measurements of Atmospheric Concentration of NOx and SO2 in the Sea Areas of Osaka Bay and Seto-inlands Sea

Measurements of atmospheric concentration of NOx and SO2 were carried out by using the chemiluminescence method of NOx and the ultraviolet-fluorescence method of SO2, and by using the training ship Fukae-maru of Kobe University of Mercantile Marine in the sea areas of 0saka Bay and Seto-inlands Sea. Measurement results make clear the folIowings. ( 1) The exhausts from ships have obvious impacts on NOx and SO2 concentration in the narrow water areas and/or in the ports where marine traffic is congested. (2) The atmosphere of the north-east area of Osaka Bay is highly polluted in some weather conditions such that the wind due to large scale pressure systems is weak and the land-and-sea breeze is prevailing.

An Auxiliary Boiler Control Simulator for Training Marine Engineers on the PLC System

Recently, computer technologies are being introduced very rapidly into the marine machinery. As for the boiler control, a new technique of PLC (Programmable Logic Control/ Controller) is being introduced and effectively used for sequential control of boiler machinery. By the introduction of PLC, which is composed of power-supply unit, CPU and I/O units, the control system is greatly simplified and become reliable. The PLC is used not only for controlling a BMS (Burner Management System) but also for a ACC (Automatic Combustion Control) system and a FWC (Feed Water Control) system in the latest boiler control. It could be expected that the introduction of PLC would decrease boiler troubles. But actual situation is not so, and boiler troubles caused by handling mistake are now increasing. Main reason for such trouble increase seems to be that marine engineers are given little chance to learn the internal structure of PLC, and the PLC is therefore an untouchable black box for them. Further they can not be given any chance for sufficient explanation on the PLC in OJT (on-the-job-training on board) . It is demanded, therefore, marine engineers should be educated for the knowledge of boiler control and PLC.Responding to the demand, the authors developed a simple boiler control simulator introduced a PLC system, and, using it, marine engineers training is being carried out in the authors institute. This paper shows a training method using the simulator, and considers a future MET (E) (Maritime Education and Training for Engineers) method.

Study on Water Quality Control for Marine Turbine Plants and Its Automation (I)

For steam turbine ships, it is very important to control accurately water quality of the main boiler and its plant. The recovery rate of condensed water in recent marine turbine plants has been increasing and approaching a perfect closed cycle, and the techniques of pH monitoring and Fresh Water Generators have been improved too. However, as for the automation of boiler water treatment, its development seems to be very late compared to other ship techniques.This paper investigates, therefore, the current situation of the water quality control of marine turbine plant in order to develop an automatic water treatment system. As the fundamental research on the boiler water quality control and its automatic water treatment, this first report analyzes theoretically the water treatment data of actual ship for making clear the impacts of (1) impurity mixing from make-up water (2) boiler compounds (3) blow-down of boiler water on boiler water quality, especially pH and PO4. The analysis shows some characteristics of boiler water quality and its treatment system which are to be helpful to marine engineers.

For Improvement of Trouble Shooting Systems of Marine Boilers

It seems to be a worthwhile subject to investigate the troubleshooting systems of marine boilers in order to improve the reliability. For development of more effective troubleshooting systems of auxiliary marine boilers, the boiler study subcommittee of the Marine Engineering Society in Japan (MESJ) has surveyed the troubles experienced in recent several years, and investigated the actual situation of monitoring systems of marine auxiliary boilers.This paper describes briefly the results of those surveys, and discusses the future monitoring systems of marine auxiliary boilers based on the preventive maintenance concept. Furthermore, a few comments will be given for the improvement of further troubleshooting systems of marine boilers.

Actual Situation of Marine Auxiliary Boilers

The Boiler Study Subcommittee of the Marine Engineering Society in Japan (MESJ) has surveyed the actual situation of production statistics and design practice of Japanese marine auxiliary boilers manufactured around 1990.This paper describes the results of the survey mentioned above and analyzes the recent characteristics of structure, performance and combustion techniques, especially comparing with those of marine auxiliary boilers manufactured in 1970s. The results of the analysis present the progress of space-saving, boiler performance of recent marine auxiliary boilers.

Change of Boiler Water Quality by Mixing of Sea Water (2)

For the water quality control of marine boiler, it is very important to investigate the effects of sea water mixing on the conditions of boiler water quality such as pH, concentrations of phosphoric ion PO43-, chloric ion Cl-, and electric conductivity EC. At first, the paper investigates theoretically the change of pH, that is molarity of hydroxyl [OH-], PO43- concentration and EC due to mixing of sea water into boiler water by the consideration of the chemical reactions between scale components and phosphate/alkali type of water treatment chemicals. According to this investigation, the paper proposes a method of automatic water quality control. Secondly the paper carries out an experimental study by the use of an actual boiler in order to confirm the validity of the above theoretical investigation. The experiment reveals the followings; (1) There is some difference between the theoretical estimation and the measurement result regarding the change of pH, PO43- concentration and EC due to sea water mixing. It is found, however, the difference has a certain regular trend being related with the mixing rate of sea water. (2) The PO43- concentration can be arranged corresponding to the addition rate of some blended type of phosphate/alkali treatment chemicals even when Cl- concentration is high, provided that hardness components do not exist. (3) When the pH is kept around 11.0, there are good correlations between concentration of [OH-] and concentrations of P-Alkalinity, M-Alkalinity and PO43-, and also between EC and Cl-. Using adequately these correlations, therefore, there would be a possibility of automatic control of boiler water quality.