scholarly journals Reengineering of the pumping system and implementation of a SCADA for the supervision and automatic control of the fire fighting system, at the Petróleos Paraguayos PETROPAR industrial plant

2021 ◽  
Vol 8 (3) ◽  
pp. 20-38
Author(s):  
Carlos Javier Ojeda Jiménez ◽  
Rodrigo Aguilera Vargas
2020 ◽  
Vol 18 (4) ◽  
pp. 86-105
Author(s):  
Stanislav R. Shakirov ◽  
Alexandr G. Kvashnin ◽  
Artem V. Pisarev

A research team from ICT SB RAS is actively developing a system to control a pilot plant for processing organic waste automatically. The pilot plant can produce thermal energy and energy carriers (solid products, e.g. bio-coal, liquid products, e.g. bio-oil, and gaseous products, i.e. synthesis gas), for example, from biomass with different chemical composition and physical properties. The equipment can process "complex" types of waste characterized mainly by high moisture and high ash content. During tests of the pilot plant, the complexity of stabilizing the parameters of technological processes and ensuring the stability and reliability of operation of the equipment of the complex as a whole were identified. This is especially important when implementing high-temperature modes of biomass processing. In order to primarily solve these most important tasks, an automatic control system of the plant is being created. When a system for automatic control of technological parameters of the gas-air path of the pilot-industrial plant is developed, a mathematical model that describes the dynamic characteristics of the gas and air paths under various throughput rates of the plant was used. When determining mathematical models, a two-way relationship between the gas path and air path was identified (interchannel connections). When technologically complex real objects of control are being automated, in the inaccuracy of a priori information about the object, when the system operates in various uncertain external and internal situations, disturbing influences, a robust control method should be used. PID controllers were selected as corrective devices for stabilizing the technological parameters that characterize the operation mode of the gas-air path of the plant including pressure in the lower part and rarefaction in the upper part of the combustion chamber. The most appropriate method for determining the PID controller settings has been elected. Synthesis and simulation of the operation of the controllers of the pressure in the lower part and rarefaction in the upper part of the combustion chamber are performed. Basing on the results of mathematical modeling, the efficiency of the controllers of the pressure in the lower part and the rarefaction in the upper part of the combustion chamber for various loads of the plant has been shown, and their stability reserves by amplitude and phase are determined. The results of mathematical modeling of the stabilization contours of the technological parameters of the gas-air path of the plant are presented for two cases: without inter-channel connections and without the account of these connections. A simulation of the joint operation of the control circuits of the gas-air path of the plant is performed. Compensators for adjacent (interchannel) connections of the gas and air paths of the plant have been developed. The advantage of the proposed automation schemes is shown.


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


1967 ◽  
Vol 28 (C2) ◽  
pp. C2-321-C2-321
Author(s):  
J. V. RAMSAY

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