Electrical Heat Tracing Research Articles

Freeze-proof method and test verification of a cold region tunnel employing electric heat tracing

In recent decades, numerous tunnels have been built in the cold region of China. However, frost damage occurs frequently inside the tunnels; this damage threatens the stability of the tunnels. In order to prevent frost damage, a method employing electric heat tracing (EHT) was presented in this study. Moreover, the EHT-based freeze-proof system layout and installation procedures were also introduced. The tunnel liner EHT system is composed of four parts: heating cable, insulation layer, protective layer and fire protection layer. This EHT system was adopted in the Dongnanli highway tunnel (located in northeastern China) to verify its applicability. In-situ test results indicated that the temperature behind the liner begins to heat up after one hour of electrifying the system; next, the temperature becomes positive and remains stable after three hours of electrifying the system. The operation of the heating system is quite stable, and the insulation effect is significant. Through the assessments of the heating efficiency that is required to reach the target temperature and a constant temperature heating effect, it is suggested that the combination of thermal insulation and electric heat tracing is feasible and effective in preventing frost damage in tunnels. The research results provide references for the design and construction of frost prevention systems in tunnels in cold regions.

열선의 직선시공과 감기시공의 동파방지 효과 비교를 위한 3차원 비정상 수치해석

This paper numerically examines, straight and twisted electrical heat trace installations for their anti-freezing effects on water inside a pipe. The unsteady incompressible Navier-Stokes equations coupled with an energy equation were solved to compare the two installation methods. The heat conduction of the pipe with a heat source interacts with the natural convection of the water, and the conjugate heat transfer was considered using a commercial code (ANSYS-FLUENT) based on a SIMPLE-type algorithm. Numerical experiments, were done to investigate the isotherms and the vector fields in the water region to extract the evolutions of the minimum and maximum temperatures of the water inside the pipe. There was no substantial difference in the anti-freezing effects between the straight and twisted. Therefore, the straight installation is recommended after considering the damage and short circuit behavior of the electrical heat trace.

Electric Heat Tracing을 위한 Zigbee 기반 통합 감시제어 시스템의 개발 및 검증

Electric heat tracing 시스템은 플랜트 내 각종 배관의 온도를 관리하는 시스템이다. 본 논문에서는 electric heat tracing 시스템을 통합적으로 감시하고 제어하기 위한 TESCON(: TEmperature Sensing and CONtrol) 시스템을 제안한다. TESCON 시스템에서 디바이스간의 정보 교환은 Zigbee 네트워크 기반의 무선 방식으로 이루어진다. TESCON 시스템의 성능 분석을 위해 컴퓨터 시뮬레이션을 수행하였다. 테스트베드를 통해서도 비슷한 결과를 얻음으로써 TESCON 시스템의 유효성을 입증하였다. 또한, 계층적 트리 토폴로지를 기반으로 하는 네트워크 분할, 채널 재사용, 프레임 집약 기법 등을 적용한 시스템 확장 방안도 제시하였다. An electric heat tracing system manages the temperature of pipes used in a plant. We propose a Zigbee-based wireless system so called the TESCON(: TEmperature Sensing and CONtrol) to monitor and control the electric heat tracing system in an integrated way. Simulations have been done to analyze the performance of the TESCON system. The performance of the TESCON system is validated by obtaining similar results via testbed operation. We also suggest an extension method of the TESCON system based on the hierarchical tree topology by adopting techniques such as network partition, channel reuse and frame aggregation.

CPVC 배관 동파방지용 열선의 위치 선정을 위한 비정상 열전달 수치해석

본 논문에서는 동절기 소방용 CPVC 배관의 동파방지를 위하여 최적의 열선위치를 에너지방정식과 비정상 비압축성 Navier-stokes 방정식을 사용하여 수치해석을 수행하였다. CPVC 배관은 탄소강관과 열용량 등 주요 물성에 큰 차이가 있어 배관 내 물의 유동에 큰 차이를 보이는 것을 확인할 수 있었다. 물의 자연대류와 CPVC 배관의 열전도가 결합된 복합열전달을 해석하였다. 상용코드(Fluent)를 사용하여 혼합 열전달 배관 내 물의 비정상적인 유동과 온도분포를 확인하였다. 소방용 CPVC 배관 단면의 하부에 열선을 설치하는 것이 다른 위치에 설치하는 것보다 시간에 따른 물의 최저 온도가 가장 높아서 동파방지에 보다 효과적인 것을 확인하였다. In this paper, a numerical experiment was conducted to find out the optimal location of electrical heat trace for anti-freeze of water inside the CPVC pipe for fire protection. The unsteady incompressible Navier-Stokes equations coupled with energy equation were solved. Since the conduction equation of pipe was coupled with the natural convection of water, the analysis of conjugate heat transfer was conducted. A commercial code (ANSYS-FLUENT) based on SIMPLE-type algorithm was used for investigating the unsteady flows and temperature distributions in water region. From the present numerical experiment, it has been found that the vector field of water inside the PVC pipe is opposite to the case of steel because of the huge difference of material properties of the two pipes. Furthermore, it was found that the lowest part of the pipe was an optimal position for electrical heat trace since the minimum water temperature of the case was higher than those of the other cases.

The Importance of Customer Service in the Indian Industry

This case let deals with the case of Indian Oil Corporation Limited (Gujarat Refinery), one of the major refineries in India and its contract with a major contractor of Insulation and Electrical Heat Tracing. It highlights the various moves (which includes tie-ups, innovative managerial practices) taken by the company towards catering to the customer needs.

Modelling and multi-scenario analysis for electric heat tracing system combined with low temperature district heating for domestic hot water supply

Low temperature district heating (LTDH) is a cost-efficient way of supplying space heating and domestic hot water (DHW) for buildings in urban areas. However, there is concern that the potential hygiene problems (Legionella) might occur if LTDH is implemented, especially for large buildings. In this study, electric heat tracing system was investigated as a solution to this dilemma. A model of electric heat tracing system for multi-storey buildings was built. Various pipe materials and insulation thicknesses as the parameters of the model were compared to make a comprehensive study. The performance of the electric heating tracing system with LTDH was simulated by taking the user pattern into account. A smart control method based on thermostatic and real-time control was developed, and compared with normal control method. The impact of user pattern was tested by applying standard, stochastic, and real load profiles to the model. The energy and economy performances of electric heat tracing system in different scenarios were simulated by Matlab. The results were compared to the conventional circulation system with the current generation district heating. The electric heat tracing system with LTDH showed good performance on heat loss saving, and it also gave benefits to district heating network by sharing part of the heating load.

Alternative solutions for inhibiting Legionella in domestic hot water systems based on low-temperature district heating

District heating is a cost-effective way of providing heat to high heat density areas. Low-temperature district heating (LTDH) is a promising way to make district heating more energy-efficient and adaptable to well-insulated buildings with low heating demand in the future. However, one concern is the multiplication of Legionella due to insufficient temperature elevation with low-temperature supply. The aim of this study was to find optimal solutions to this dilemma for specific situations. The solutions were of two types: alternative system designs and various methods of sterilization. The alternative design approach can eliminate the risk factors of Legionella by local temperature boosting and restricting system volume. Decentralized substations, micro heat pumps, electric heating elements and electric heat tracing are all investigated as alternative designs. With regard to sterilization methods, thermal treatment, ionization, chlorine, chlorine dioxide, ultraviolet light, photocatalysis and filtration are discussed as the most frequently used methods in hot water systems. The characteristics, efficacy and operation methods of LTDH using the solutions investigated are documented and compared. Finally, recommendations are given for their use in practice. Practical application: The methods for inhibiting Legionella should fit into applicable situations according to their characteristics. This study aims to recommend optimum solutions for inhibiting Legionella in LTDH scenarios, and includes a comprehensive overview of their efficiency, installation, operation and costs, so as to give adequate information for selecting appropriate solutions. In addition to sterilization methods, alternative system design implemented with new technologies can also help prevent Legionella in hot water systems. They have the additional benefit of reducing the heat loss of the hot water system. The alternative design solutions both enrich our options for water sanitation and improve the energy efficiency of our energy systems.

New Technology and Experimental Study on Snow-Melting Heated Pavement System in Tunnel Portal

In recent years, with the rapid growth of economy and sharp rise of motor vehicles in China, the pavement skid resistance in tunnel portals has become increasingly important in cold region. However, the deicing salt, snow removal with machine, and other antiskid measures adopted by highway maintenance division have many limitations. To improve the treatment effect, we proposed a new snow-melting approach employing electric heat tracing, in which heating cables are installed in the structural layer of road. Through the field experiment, laboratory experiment, and numerical investigation, structure type, heating power, and preheating time of the flexible pavement heating system in tunnel portal were systematically analyzed, and advantages of electric heat tracing technology in improving the pavement skid resistance in tunnel portal were also presented. Therefore, such new technology, which offers new snow-melting methods for tunnel portal, bridge, mountainous area, and large longitudinal slope in cold region, has promising prospect for extensive application.

Grey Relational Analysis and its C# Program in Analysis of Rigid Polyurethane Foam

With the rapid development of petroleum industry in China, the electrical heat tracing becomes very important for viscous oil transportation, while the heat insulation acts as the key to the application of electrical heat tracing. Rigid polyurethane foam has been widely used in long-distance pipelines for its advantages as the heat insulation material. However, there is also a lack of systematic analysis on the impact factors of such material, thus it is urgent to find out a practical method to distinguish the major impact factors. This paper introduces the Grey Relational Analysis (GRA) with its C# program, and it is proposed to analyze the actual impact factors of rigid polyurethane foam. The application shows that this method is practical, simple, rapid and accurate, so it suitable for similar applications in other fields.

소방 배관 동파방지용 열선의 위치 선정을 위한 비정상 열전달 수치해석

소방 배관 동파방지용 열선의 위치 선정을 위한 비정상 열전달 수치해석

Electrical Heat Tracing for Surface Heating on Arctic Vessels and Structures to Prevent Snow and Ice Accumulation

The Proposed “IEEE 45.8 Recommended Practice for Electrical Installations on Shipboard - Cable Systems” will reference EHT (Electrical Heat Trace) for heating pipes, tanks, and instrumentation on-board ocean-going vessels. The globally recognized IEEE 515 Standard for resistance heat tracing addresses “traditional” freeze protection and temperature maintenance applications on-board tankers and FPSO (Floating Production, Storage, and Offloading) facilities, but not for keeping un-insulated surfaces above freezing. As fossil fuels are discovered offshore in arctic regions, their development requires increasing resources to prevent the accumulation (or melting) of snow and ice. Outdoor stairs, handrails, walkways, and other exposed and un-insulated surfaces require protection in these harsh environments. These represent growing requirements for EHT to be installed on, in or under surfaces to reduce unsafe conditions during normal operations or during emergency conditions.

Calculation and Analysis on Thermodynamics Calculation of Nature-Gas Pipelines with Electric Heat Tracing

In order to restrain the hydrate formation in the gas transmission pipeline, according to the heat transfer theory of fluid in the circular tube of multilayer cylindrical wall, comprehensively considering many factors such as earth temperature variation, natural gas physical property and so on, we theorized numerical method and computational formula of thermodynamic calculation of buried electric heat tracing gas transmission pipeline, which are used to the field calculation. The results show that the outlet temperature of pipelines with electric tracing ribbon has a sensible rise, and the minimum is 3.8°C, under the conditions given in this paper, the maximum ups to 19.8°C, the relative percentage error between calculation results and actual measurement values is less than 5%, so we can concluded that the derived temperature drop formulas and the calculation software can totally meet the requirement in oilfield production.

Application of Fuzzy Analytic Hierarchy Process in Selection of Electrical Heat Tracing Elements in Oil Pipelines

The Fuzzy Analytic Hierarchy Process (FAHP), based on the combination of Fuzzy Comprehensive Evaluation and AHP, is introduced in this paper and C# language is proposed to program its mathematical model. Moreover, such program is applied in the actual selection of the electrical heat tracing elements in oil pipeline system. The application shows that it is scientific, reliable, accurate, simple and rapid, which makes it suitable for other evaluations.

First Application of Progressing Cavity Pumps for Appraisal Well Testing in the Ugandan Albertine Graben Basin

Summary Over 28 production well tests and two interference tests have been conducted in the Albertine Graben basin in Uganda since the first oil discovery in 2006. The Uganda crude is moderately viscous, and low-gas/oil ratio (GOR), and later discoveries were mostly in shallow lower-energy systems. In addition, Uganda crude has relatively high pour points and wax appearance temperatures (WATs), which result in flow-assurance challenges during production testing operations. Production challenges brought about by the low energy scenario are offset by high formation permeability (mostly in the multi-Darcy range). Field X was discovered in 2008 by Well X-1, and subsequently appraised by several wells. Zone 1 of Well X-1 was production tested under natural flow without a rig. Although hydrocarbons were brought to surface successfully during the testing operation, the maximum flow rate achieved was approximately 262 BOPD, and a stable flow rate could not be sustained. Fluid-segregation effects distorted the early-time data. In addition, flow-assurance challenges prevented acquisition of late-time response from the pressure buildup (PBU). Therefore, important dynamic information, particularly in regard to flow barriers, was not obtained. A change in completion philosophy was proposed after detailed analysis of the test results. Well X-1 was retested with a new completion design incorporating real-time surface-readout (SRO) pressure and temperature monitoring capability, a hydraulically controlled inflow control valve (ICV), a progressing cavity pump (PCP), and a surface-controlled electrical heat trace system. High-quality well-test data was acquired, and the real-time data was used extensively throughout operations to optimize flow and buildup periods and well operating envelopes. Several challenges were faced during the first completion run, leading to the use of the contingent insert PCP system to retest Zone 1. This paper highlights the first application of a PCP completion in Uganda and describes the challenges faced during the completion and well-testing operation. The experience from Well X-1 has demonstrated that high-quality exploration and appraisal well-test data can be acquired using a PCP completion. Similar well-completion designs will be used in Uganda for appraisal of other discoveries.

Electrothermal Heating of California Oil Wells: A Case Study of Enhanced Oil Recovery of Shallow Wells

A case study of enhanced oil recovery of shallow wells is presented. This article explores the utilization of electric heat tracing (EHT) as a viable technology solution to bridge the gap between economic and uneconomic when considering heavy oil wells in the California region, wherein production has dropped to an unacceptable level or production is not economically desirable. Polymer flooding is a similar approach to surfactant flooding. Primary recovery involves the natural pressure of the reservoir along with artificial lift methods to move oil reserves to the surface. EHT has been considered an effective solution for flow assurance, wax, paraffin, and hydrate concerns for many decades.

Electric Heat Tracing Controls: Its Integration in Industrial Facilities

Electric heat tracing systems have been around for decades. They are often taken for granted until a failure disrupts a process and, in the worst-case scenario, causes a costly unit-wide shutdown of an industrial facility. This is especially the case in the petroleum and chemical industries, where critical processes have evolved, requiring tighter control and monitoring along with predictive diagnostics. Using proven technologies, heat tracing systems can be brought into the 21st century with real-time protection, monitoring, and control to improve process reliability.

Research on Impact Factors of Thermal Insulation Material Based on Grey Relational Analysis

According to application of thermal insulation materials in the practical construction of electrical heat tracing in viscous oil pipeline, impact factors of rigid polyurethane foam widely used as new insulation material are systemically analyzed by Grey Relational Analysis (GRA) in the theory of Grey System to find out priorities among those factors. To further study their performances and to improve the quality of constructions, ten field experiments were carried out in Tanggula Mountain. The foaming conditions and the performances of the rigid polyurethane foam were recorded to be analyzed by GRA. The analysis results, acting as scientific guidance for construction, show that the insulation quality of rigid polyurethane foam is mainly determined by the ratio of components, thus the priority is to control such dominant factor and overall consideration of other factors should be taken to ensure insulation quality in the foaming process. More field experiments prove that the ratio should be controlled between 1.15 and 1.18 to ensure the thermal insulation.

Research Situation and Prospect for Highway Snowmelt Deicing Technology with Electric Heat Tracing

The frequency of worldwide disastrous weather is intensified by the global climate warming. The disastrous weather such as freezing rain and snow is extremely disadvantageous to the vehicle performance and safety. This paper summarizes and classifies the current snowmelt deicing methods at home and abroad; emphatically proposes the trend of future active development for snowmelt technology and introduces the snowmelt deicing technology of electric heat tracing, which is the competed developing new technology in the countries of cold region acting as one of the snow removal measures in winter cold regions. The electro-thermal snowmelt deicing technology involves relatively wider field of knowledge, whose research and development are also increasingly connected with the development of other technologies. This paper reviews the development history of electro-thermal snowmelt deicing technology and summarizes the main research condition of domestic electro-thermal snowmelt deicing technology in the last few years, furthermore looks forward the development and application prospect of electro-thermal snowmelt deicing technology by brief description of the current research situation.

Recurrence of Fecal Coliforms and Salmonella Species in Biosolids Following Thermophilic Anaerobic Digestion

The U.S. Environmental Protection Agency (U.S. EPA) Part 503 Biosolids Rule requires the fecal coliform (indicator) or Salmonella species (pathogen) density requirements for Class A biosolids to be met at the last point of plant control (truck-loading facility and/or farm for land application). The three Southern Californian wastewater treatment plants in this study produced biosolids by thermophilic anaerobic digestion and all met the Class A limits for both fecal coliforms and Salmonella sp. in the digester outflow biosolids. At two plants, however, a recurrence of fecal coliforms was observed in postdigestion biosolids, which caused exceedance of the Class A limit for fecal coliforms at the truck-loading facility and farm for land application. Comparison of observations at the three plants and further laboratory tests indicated that the recurrence of fecal coliforms can possibly be related to the following combination of factors: (1) incomplete destruction of fecal coliforms during thermophilic anaerobic digestion, (2) contamination of Class A biosolids with fecal coliforms from external sources during postdigestion, (3) a large drop of the postdigestion biosolids temperature to below the maximum for fecal coliform growth, (4) an unknown effect of biosolids dewatering in centrifuges. At Hyperion Treatment Plant (City of Los Angeles, California), fecal coliform recurrence could be prevented by the following: (1) complete conversion to thermophilic operation to exclude contamination by mesophilically digested biosolids and (2) insulation and electrical heat-tracing of postdigestion train for maintaining a high biosolids temperature in postdigestion.

Beyond Electrical Heat Tracing: Safety Showers Update

Since their introduction to industry, safety showers and eyewash stations have required winterization to ensure operation during subfreezing ambient conditions. However, a move to provide tempered water for chemical burn victims will have significant implications for present electrical heat tracing practices on safety shower applications.