Automation in Petro-Chemical Industry

Design & SIL Calculation of Safety Instrumented Function Loop

2017, 53(4): 0-0.

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Introduce the grading method of safety instrumented level (SIL) of safety instrumented function (SIF), then introduce the calculation method of SIL certification by IEC 61508 and ISA TR84.00.02; Take ordinary and SIL certification instruments for example，calculate the average of probability of failure on demand，obtain the SIL of SIF loop.Compared with ordinary and SIL certification instruments SIF loop, give the suggestion to SIS design combined the actual design and application situation.

The Advancement Research on Foreign Gas Detector Operation and Maintenance Standards

2017, 53(4): 0-0.

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Combustible gas detector was the important facilities for oil and gas station equipment and personal safety. China have been developed the design, construction, and calibration standards of gas detectors, with the gas detectors operation and maintenance standards need to be improved. The paper introduced the advanced experience and recommended practice of American combustible gas detector from product selection, sensor redundancy design, setting position, alarm setting value, operation and maintenance and training. The advancement of ISA-60079-29-2-2012 included double or three redundancy design of remote control combustible gas detector sensor in special place, adopting gas detectors protection measure in complex place and bad weather condition, alternative measures under combustible gas detector failure condition. Finally, the suggestion of adopting American standards to improve domestic combustible gas detector standards were maded.

Method of Instrument Selection in Coal Fired Flue Gas Desulphurization and Denitration Plant

2017, 53(4): 0-0.

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This paper introduces the method of instrument selection in desulfurization and denitration Plant of coal fired flue gas from Heat conducting oil boiler, combined with practical experience and effect, focus on instrument selection on key control parameters, include pressure, flow, liquid level, density, PH instrument and control valve. According to the practical experience, widespread wear and corrosion and clogging condition exist in flue gas desulfurization and denitration process, higher requirements for the material and instrument selection, reasonable selection and stable operation of the instrument can ensure the effect of flue gas treatment, prolong the service life of the instrument, and can reduce the cost, optimize the investment.

Calculation of flow coefficient of two-phase flow control valve in flashing case

2017, 53(4): 0-0.

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There exist a lot of gas-liquid two-phase flow in the industrial process, but for calculation of flashing case two-phase flow control valve, usual only is simple addition for each phase flow coefficient, so this is cannot meet requirement of accurate flow control. So the paper, that refer to arithmetic of safety valve, flash factor and effective density method, deduce a new calculation method that meet requirement of gas-liquid two-phase flow control valve flow coefficient. The results show that adopt the method of calculation is more close to the actual process, and improve vacancy of calculation of two-phase flow control valve, and offer reference for the similar calculation for later.

Study on Optimization Technology of CFB boiler combustion

2017, 53(4): 0-0.

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Abstract： In this paper, the CFB boiler combustion efficiency in a power plant is taken to analyze the factors that affect this. The improved BP neural network prediction model is established, which is based on the model output for the boiler combustion efficiency and NOx emissions, and the genetic algorithm is used to optimize the parameters of the model. he boiler efficiency and NOx emission are optimized by adjusting combustion parameters. Neural network training based on real operation data of boiler。 MATLAB simulation of thermal test and advanced algorithm using boiler operation data, the simulation results show that the proposed model and algorithm are effective for the optimization of boiler combustion.

The Control Studies of Mamdani Fuzzy Neural Network

2017, 53(4): 0-0.

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Abstract：In the thermal power plant limestone / gypsum wet flue gas desulfurization system，PH value of slurry has a great influence on desulfurization efficiency.The control process of PH value of slurry has nonlinear, large lag and variable gain process.Therefore, this paper analyzes and studies the PH value of slurry from the direction of desulfurization efficiency.In this paper, Mamdani fuzzy neural network is used to establish the controller and used in the slurry PH value control to further improve the search ability of the network in the control to achieve better control effect.The fuzzy neural network not only contains the fuzzy reasoning ability of fuzzy control to deal with the uncertain information, but also contains the neural network self-learning ability.It can rely on fuzzy language rules to train the network, making it easier to determine the structure and parameters of the neural network.Based on the Mamdani fuzzy neural network slurry PH value control for MATLAB design and simulation, and compared with the conventional PID control,The results show the effectiveness of the method.

Optimization Program of Control for Steam Compressor

2017, 53(4): 0-0.

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Aiming at problem of easy surge、liquid hammer and break-down of the compressor, the optimization scheme of anti-surge control and superheating steam control was presented, and modification of start and stop production was carried out. After repeated testing and start-up it’s demonstrated that the modified program is logical and ensures the compressor runs stable.

Design of Pressure Regulating System based on Fuzzy Control

2017, 53(4): 0-0.

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The pressure regulating device for natural gas is a critical facility in the gas transmission station. Its performance greatly depends on the control algorithm. However, in reality, the traditional regulating system still exists some problems in the following aspects: big output pressure fluctuation, slow response, easy to overshoot. This paper focuses on the study into the phenomenon existing in SINOPEC Sichuan to Eastern China Gas Transmission Pipeline. In order to achieve rapid and accurate control of output pressure, we develop a new fuzzy control algorithm and implement the program using a Allen-Bradley Programmable Logic Controller (AB-PLC). Finally, a verification experiment was conducted at Xiantao gas transmission station. The results demonstrate the excellent performance of control system on stable output pressure, response latency and pressure overshoot.

Development and Implementation of Cracking Severity Control System for Ethylene Plant of Qilu Company

2017, 53(4): 0-0.

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Auxiliary Application’s Realization of WeChat Mini Program for Petroleum Measurement in Liquefied Products’ Storage

2017, 53(4): 0-0.

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Petroleum measurement is often used in the process of the liquefied products’ storage, the GB/T1885-1998 provides the standard density and volume correction factor for petroleum measurement. Via consulting the parameters and the formula of the ISO91-1 petroleum measurement tables-part 1: tables based on reference temperatures of 15 degrees C, using the iterative method can solve the standard density and volume correction factor of reference temperatures of 20 degrees C, which is used in our country. Based on this, we can develop a WeChat Mini Program,which will have the good use value.

Based on iAutoLink handover light hydrocarbon development and application of the monitoring system in the refinery

2017, 53(4): 0-0.

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Abstract: the transfer of light hydrocarbon measurement monitoring system is a kind of intelligent compensation flow computer system, all based on iAutoLink IOT intelligent terminals and special research and development, which combines data collection, data storage, data processing, data forwarding and other functions in one, is mainly used in real-time database, MES, ERP system such as the upper platform providing front-end data acquisition, data security isolation and standard communication interface, etc. In light hydrocarbon measuring abnormal cases in a timely manner to track and lighter hydrocarbon from the oil refinery and settlement monitoring plays an important role.

The origin 3:1 turndown ratio of orifice

2017, 53(4): 0-0.

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Standard differential pressure flowmeter uses different methods to ensure measurement accuracy at different stages of development. Before GB2624-81 released, we set the boundaries of the larger Reynolds and compression turndown ratio range, for instance compress turndown ratio to 3:1. So people build the concept of orifice turndown ratio is 3:1. At this time, the flow coefficient α was treated as constant. Till GB2624-93 released, it made possible for automatic correction of flow coefficient nonlinear in the flow transmitter or flow display device on account of CPU. Thus restoring the discharge coefficient (or flow coefficient) non-linear original appearance, treated discharge coefficient as variable, and built model of C=f(β,ReD) . Correct discharge coefficient nonlinear automatically in the flow transmitter or flow display device to make up for its deficiencies. This improvement expands the turndown ratio, and reduces the system uncertainty significantly. This paper provides a complete validation data.

Development of Portable Sampler for Liquefied Natural Gas(LNG)

2017, 53(4): 0-0.

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The study background and structural components of one new portable sampler for liquefied natural gas are introduced. The sampler mainly includes the gasification system, digital display system, receiving device and power supply, etc. The in-situ tests prove that the portable gravity sampler is simple in structure and easy for operation.

The Design and Simulation Experiment Verification About a High Pressure Differential and Small Flow Control Valve

2017, 53(4): 0-0.

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In order to solve the high pressure differential and small flow control working condition, combining with all advantage of Single Seated Control Valve and Balance Cage Control Valve , designed a new type fine adjustment of the small flow control valve, and by calculating CFD fluid analysis software has carried on the simulation research.To better verify the applicable performance of the valve, the 3D model is established, and the working condition of the scene of a chemical plant parameters as boundary conditions, numerical simulation was carried out on the model of internal flow, obtained the internal flow field results.According to the results showed that the valve in high pressure condition has better depressurization effect, and good regulation performance, comply with the design of the intended purpose.

Application of Regulator with Back Pressure Control in LPG Measurement System

2017, 53(4): 0-0.

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Liquefied petroleum gas (LPG) is gasification medium. Usually we use mass flowmeter with high accuracy to ensure the accuracy of dynamic measurement system and protect the interests of both the seller and the buyer. Pressure before mass flowmeter must be greater than specified minimum pressure to avoid producing gas-liquid two-phase flow. According to SY/T6042, several issues related to regulator with back pressure control are expounded from the points of blowing: methods for calculating minimum measuring pressure of LPG; pressure control of dynamic measurement system ; application of regulator with back pressure control.

Offshore Gas Field Control System Optimization

2017, 53(4): 0-0.

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To facilitate the control system of daily maintenance & test, reduce the time to investigate the cause of alarm, and improve the efficiency of dealing with emergency shut down, the Panyu 30-1 gas field of control systems has been done two optimization, including optimization of signals between FGS and ESD, classification of DCS alarm events by cause.After completion of this two optimization, the Panyu 30-1 platform can test FGS the whole logic chain and verify the reliability of the FGS at any time. The time of to find out the time point of the emergency shut down reduced from 5-10 minutes to 30 seconds, and the platform unplanned production shut down can advance half an hour to resume production, reduced the production losses, improve the production efficiency. The two completion ideas of the control system optimization can be used for new platform design and old platform control optimization.

The analysis and suggestion of overpressure blowdown system in Moxinatural gas purification plant

2017, 53(4): 0-0.

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The function of overpressure blowdown system is relief and vent when the accident was happening or emergency in natural gas purification plant. And in recent years, the accident of evacuation system cause property loss. So it is very important to find and resolve the problem of overpressure blowdown system, which guarantee long-term safe and stable operation of purification plant. This study analyses on these curity risk existing of overpressure blowdownsystem by vent setting, supreme vent amount, extreme environment in Moxi natural gas conditioning plant, and advances some suggestions on the rectification and reform.

Application for Special Restrictive Orifice in the Natural Gas Chemical Engineering

2017, 53(4): 0-0.

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When flow pass through a restrictive orifice, the bigger differential pressure is, the bigger flow velocity is. As differential pressure increases to critical value, velocity will remain a constant and choked flow occurs. Restrictive orifice is used as flow limiter in the event of a downstream system failure. This paper studies the effect of orifice diameter, thickness, entrance sharpness on choked flow, and lists critical flow equations. The restrictive orifice is used in the MKP methanol project.

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