Automation in Petro-Chemical Industry

On the requirement of the grounding resistance value for a control system

2017, 53(5): 0-0.

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The requirement of the grounding resistance value for a control system is seldom discussed in the literature. Many domestic manufacturers of control system often use to 4Ω as the requirement of grounding resistance value. Through the analysis, we can get the following conclusions: A. Action current of circuit breaker or fuse and resistivity of soil (or ground) decided to requirements of protection grounding resistance value for control cabinet when equipments in a cabinet are case of failure; insulation performance and symmetrical performance of control system decided to requirements of working ground resistance value. B. The requirements of the working grounding resistance value for a control system is a property of the control system; and the requirements of the protection grounding resistance values is a property of the cabinet. The requirement of the grounding resistance value to be specified in the product specification of a control system shall be the requirement of the working grounding resistance value. C. The requirements of working grounding resistance for a control system are not same compared with the requirements of protection grounding resistance for a cabinet, and the expected value of grounding resistance value for a engineering design should be less than one of the smaller.

Research on the Safety Management Systems of Long Distance Pipeline in North American

2017, 53(5): 0-0.

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It was the important political value to guarantee oil & gas pipeline transportation safety. The paper expounded oil & gas pipeline safe management system of the United States in detail form national supervision agency, laws and regulations, standard and specification, and pipeline safety measures. Emphasis was the technical standards system of oil & gas pipelines in the United States, especially the pipeline integrity management standard system. The recommended practice of American pipeline operator was also introduced, including National Pipeline Mapping System, and One-call Notification System, and pipeline information transmitting, and news media reporting and charitable donations. By the reference of advanced experience of American pipeline safe management system, it was the great importance for regulating the responsibilities of safety supervision departments, and strengthening the pipeline legislation, improving the pipeline standards, and establishing and improving China oil & gas pipeline safety management system.

Discussion on guiding principles to measure the safety integrity level

2017, 53(5): 0-0.

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This article from the basic concept, discuss four guiding priciples about the safety integrity level measurement, requirements for probability of failures, hardware safety integrity architectural constraints, requirements for the control of systematic faults and software Requirements. All discussions are base on SIS system base specification IEC 61508. This article also gives the design and application advices.

The Failure Risk Research of the Onshore Oil and Gas Pipeline Based on Bayesian Network

2017, 53(5): 0-0.

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By using the advances of uncertainty reasoning and modeling of Bayesian network, a new method based on BN is used in risk analysis for the failures of onshore oil and gas pipeline with multi factors and multi conditions. At first, the factors inducing the failure of onshore oil and gas pipeline , such as natural disasters, corrosion and construction management were analyzed and modified, probability calculation model based on BN is established. Then exampled with a pipeline, the failures with single factor and multi conditions, double factors and multi conditions, multi factors and multi conditions were quantitatively analysis and assessment, the failure probability of pipeline and the importance of the basic factors were obtained. It has been show that the evaluation method based on BN used in risk analysis for the failures of onshore oil and gas pipeline, probability distribution of the base events can be calculated more accurately, it also can find out the the most likely cause of the accident at the same time. Finally this method will provide reasonable suggestions for the risk control and safety management of onshore oil and gas pipeline accidents.

Combustion control design of the sulfur recovery unit eactor furnace

2017, 53(5): 0-0.

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According to the characteristics of sulfur recovery unit reactor process sulfur reactor control scheme was designed, ensures that flame temperature can be efficiently controlled to ensure complete combustion and decompose of acidic gas, the realization of the control scheme is expounded the concrete ways and effect in the actual production process.

Application of PLC technology and FCS technology in SCADA system of DONGLIN oil pipeline

2017, 53(5): 0-0.

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In the oil pipeline transportation process, stable and reliable automatic control system is particularly important, the advanced SCADA system for centralized monitoring, control and management of all equipments and pipelines, to achieve safe transportation, scientific management, reduce consumption and improve economic efficiency. The traditional PLC control technology is used in the automatic control system of crude oil pipeline, But in recent years, the installation of Fieldbus intelligent equipment, FCS system has been widely applied, From the field device junction box to the central control room with a twisted pair to complete digital communication between each intelligent device sharing a twisted pair shielding line, which greatly reduces the cost of the construction site and the large number of control cable and auxiliary material. In this paper, combined with the Donglin oil pipeline in the upgrading of the SCADA system, the successful use of FCS technology and the combination of the case of the original PLC technology, the introduction of the Donglin oil pipeline station control SCADA system.

Research on Anti-surge control based on TRICON controller for product gas compressor

2017, 53(5): 0-0.

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Centrifugal compressor is an important equipment in petrochemical industry. This paper refers to the compressors of Shenhua Xinjiang 680KTA Coal Based New Material Project 600 KTA Light Olefins Recovery Unit, which accomplish two functions of material transportation and refrigerant supply. In this paper, the control system selection, configurations, control scheme of compressor are studied, and the improvement measures are put forward for the existing compressor control scheme.

Human-Simulated Intelligent Pressure Control System Design for Regulator Skid

2017, 53(5): 0-0.

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Abstract: Aiming at the problem for the gas regulator skid pressure control system, pressure control is not smooth which caused by large-scale flow fluctuations and large dead-zones in the value, this paper designs a intelligent control system. The system includes interference controller, PI controler and Human-Simulated Intelligent controller. The interference controller uses the feedforward control algorithm to compensate for the interference and PI controller adjusts the pressure. The Human-Simulate Intelligent controller realizes the dynamic handover control according to the system running state and put forward a non-equal-width switch strategy to overcome the impact of valve dead-zone to improve the real-time. Simulation results show that this system can effectively suppress the flow disturbance and overcome the influence of the valve dead zone, not only can improve the pressure control precision but also reduce the switching frequency of the valve.

Identification and Parameter Tuning of Combined Integrating System Based on Relay Feedback

2017, 53(5): 0-0.

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An improved type of relay identification method is extended to the parameter identification of the combined integrating system. The parameter estimation of combed integrating system with method of approximately describing system by first order or second order plus dead-time model is replaced. A combined integrating controller is designed, based on the estimation parameters. With the concept of phase offset, the deviation between the oscillation point in the relay test and the critical value of the limit state of the controlled object is compensated, and the parameters of the combined integrating object in the frequency domain are identified and the recognition accuracy is higher. The online calculation of the phase shift angle avoids the process of obtaining a priori information by multiple iterations and shortens the adjustment time. The simulation results verify the practicability and validity of the algorithm.

Analysis on Security of Oil/Gas Pipeline SCADA System

2017, 53(5): 0-0.

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Pipeline is the lifeblood of petroleum and gas industry. SCADA system on Oil/gas pipeline is the system for monitoring and controlling of pressure, temperature, flow and valve status. its security is self-evident. This paper describes the system organization of the current oil /gas pipeline SCADA system, analysis the existing security risks, combined with the actual situation of the project, and puts forward the advantages of improving the security of SCADA system from three aspects: hardware and network architecture, software and management. Such as: the station control system restricts cross-domain access, designs a vertical hierarchical protection in the Control Center , a horizontal deployment of security platform to achieve all the security log can be traced; all workstations should be protected by a industrial firewall security guards, regularly updates virus gene and scan security risks and repaired immediately; all system operators should be trained, and formulating relevant operational procedures to reduce system security risks.

Application of Optical Fiber Trace Moisture Analyzer

2017, 53(5): 0-0.

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Trace moisture online measurement is widely used in the petrochemical industry to optimize the production process and monitoring safety. In this article, the principle and shortcomings of the traditional trace moisture analyzer are introduced, and the measurement principle and advantages of the optical fiber trace moisture analyzer are introduced. Based on the refining conditions of olefins, the advantages of fiber-optic method in engineering application are verified, and the practical engineering application is expounded in detail. At the end of this article, the optical fiber trace moisture analyzer important role and significance are reflected.

Type Selection of Control valve in Hemi-Dihydrate Process of Phosphoric Acid Plant

2017, 53(5): 0-0.

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As the development trend of phosphoric acid industry in china, Hemi-Dihydrate (HDH) process has a broad application prospect. The HDH process and the according corrosion features are briefly introduced. The material selection for diaphragm valve and plug valve in various corrosive mediums is emphatically illustrated. Based on the application experiences in two HDH process of PA plant, the recommendations of type selection of control valve applied to all corrosive mediums are provided.

Minimum seawater flow calculation of Open Rack Vaporizer in different conditions

2017, 53(5): 0-0.

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Open Rack Vaporizer (ORV) is one of the main gasification in LNG terminal. And domestically, it is usually used by the model that a seawater pump rated flow operation provides seawater for a single ORV. But actually, with different LNG flow, pressure, temperature, component and seawater temperature, the seawater flow of ORV required is different. So the current operation model is general excess energy. In order to determine the required minimum seawater flow, Firstly, Based on ORV performance curves to determine its mechanically limited LNG flow and through 1sOpt software, using multivariate nonlinear fitting finds the function that different LNG flow, pressure and seawater temperature correspond to seawater flow under specific conditions. Secondly, with BWRS function to calculate ORV entrance LNG , export natural gas(NG) enthalpy in specific conditions and actual parameters. And then, by the principle of conservation of energy, obtain actually required minimum seawater flow. Finally, by computer programming, design calculation software. To test and verify the calculation accuracy of calculation, calculate theoretical minimum seawater flow about actual process by the data of performance curves, Apsen_Plus and conservation of energy. And by comparing it and software calculated values, obtain relative error. The results prove that, the maximum relative error is less than 3% and software can better calculate the required minimum seawater flow, and provide a theoretical reference for ORV optimization, energy-saving operation and seawater pump selection, frequency conversion.

Industry process gas chromatographs measure fuel gas calorific value

2017, 53(5): 0-0.

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using process gas chromatographs continuous measure fuel gas calorific value in Syngas processing plant, based on design standard to validation analyzer data

Analyze and Treat the Distributed Capacitance from Long Distance Control Cable

2017, 53(5): 0-0.

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Aiming at treating with the influences of the distributed capacitance coming from the long distance control cable in the project design, this article makes some analysis according to the principle, discusses the influences from the distributed capacitance and channels to weaken them, and then finds the specific reason, at last gives the specific solution by aid of the circuitous philosophy formula combined with the engineering experience. This solution can eliminate the influences from the distributed capacitance coming from the long distance control cable, which has been proven by the real project, so it is reliable and practical.

GE Gasifier Lock Hopper Sequence Control Switch Valve Failure Analysis and Prevention Plan

2017, 53(5): 0-0.

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GE CWS gasification process in the process of lock hopper arrange control run, lock hopper system often under high pressure and low pressure switch frequently, so the lock hopper sequence control switch valve has been widely used in this process, the switch valve to continuous operation of the gasifier plays a vital role.

Application and analysis of zirconia analyzer in boiler flue gas measurement

2017, 53(5): 0-0.

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