Eco-Friendly Electric-Powered Hydraulic Fracturing Towards Shale-Gas Recovery: Efficiency, Economics and Field Application

The recovery of unconventional gas fields especially the shale gas is of great significance to clean energy supply. High productivity of shale gas is attributed to the large-scale hydraulic fracturing with high operating pressure (80-100MPa) and discharging rate (14-18m3/min). More high-horsepower fracturing vehicles driven by diesel engines result in higher CAPEX. The low operation efficiency and unexpected maintenance negatively affected the economics performance of operators due to unacceptable OPEX. The fully electric-powered hydraulic fracturing solution was proposed as the alternative to the diesel-engine fracturing vehicles in this article. The skid-based electric pumping units were newly developed with advantages of high power density (6000HP per unit), Variable Frequency Drive (VFD) modules integration, fuel cost saving, low maintenance expenditure and eco-friendly operation. The field application was conducted in one pad of N209 in shale gas field, Sichuan, China. The electric-powered system, consisting of pumping units and blenders with other facilities, was deployed on the operation site. One large-capacity electric power grid (35kV and 30000kVA) was constructed for both drilling and massive multistage fracturing. The operation team successfully performed all hydraulic fracturing jobs as required with 7.4×105 kWh of total power consumption. The system functioned reliably without large faults occurred. The electric-powered solution was comprehensively evaluated and compared to the diesel-engine fracturing solution in terms of CAPEX, operational efficiency, power consumption, maintenance and fleet crew cost. The novelty of the technology is the fully electric-powered hydraulic fracturing system with large-capacity electric power grid. It is concluded from the field application that the electric-powered fracturing technology is qualified for unconventional reservoirs development.

Modifikasi Mesin Pengupas Kulit Pinang Kering

Due to the weaknesses of some existing areca peelers, some modifications were made. Modifications were made to the gear stripper, the addition of the inlet funnel, the gear stripper cover, and the exit funnel. The purpose of this modification of the design of the areca nut peeling machine is to make it easier for areca-producing farmers to peel their skin. Engine design specifications, using a 1/2 HP motor with a speed of 1500 rpm, 2-inch, and 10-inch pulleys, and a capacity of 5.16 kg/hour. The result of this modification is stated to be able to perform stripping with a large capacity. This machine is expected to be able to meet the needs of manual areca nut peelers to increase productivity.

Photovoltaic Power Plant Collection and Connection to HVDC Grid with High Voltage DC/DC Converter

Photovoltaic (PV) power plant collection and connection to a high voltage direct current (HVDC) grid has many advantages. Compared with the traditional AC collection and grid-connection scheme, it can reduce the power conversion links and improve the system efficiency. As one of the most important devices in the application of a PV HVDC collection and grid-connection system, a high voltage, large capacity, high step-up ratio DC/DC converter is the critical technology. A DC/DC converter scheme based on a boost full bridge isolated power module cascaded in input parallel output series (IPOS) structure is proposed to meet the technical requirements of PV power conversion with high voltage, large capacity, and high step-up ratio. The operation mode of the power module is analyzed, the soft switching method is proposed, and the constraint to realize the soft switching of the power module is deduced. Aiming to resolve the problem of multi-module voltage and current equalization in a cascaded DC/DC converter, a distributed module equalization control strategy is proposed to realize the reliable operation of a power module and converter. A 5 kV/80 kW standard power module is developed, the DC/DC converter experimental platform is built, and the proposed system scheme and control strategy are verified by experiments. Based on a 14-power module input parallel output series connection, a ±30 kV/1 MW PV DC/DC converter is developed, a ±30 kV PV HVDC collection and grid-connection demonstration system is established, and the experimental test is completed to realize the stable operation of the system.

Crude Oil Storage Tank Refurbishment Duration Optimized by 40% Through Advanced Techniques

Crude storage tanks are an important asset in every oil company. Having adequate storage capacities is important economically and ensure steady supply of oil in the market. Hence, taking a huge tank out of service for refurbishment is technically and safety critical, and as much as putting it back into service on time. This paper presents an advanced methodology and assessment of tank refurbishment process of large capacity Crude Storage Tanks, in compliance with the International Codes and Standards resulting in optimization of the project schedule by approximately 40% as compared to conventional methodology of refurbishment. By deploying the advance techniques, detailed assessment, and dynamic planning we have been able to accelerate the completion of the project, improve tank availability time without compromising with the Integrity and HSE.

Crowd Emergency Evacuation Simulation Time Analysis via Obstacle Optimization Strategy

The crowd evacuation simulation is essential to provide important results for occupants, especially in the large capacity building compared to the human fire drill exercise. The strategy of evacuation such as the use of obstacles may need to be adapted by many organizations as an aid to help in visualizing and estimating the evacuation time during an emergency. During certain crowd events, they may consider the various setting of the object to ensure smoothness and effective crowd evacuation flow. In this paper, it aims to provide the simulation with 100-1000 agents and testing with obstacle using Anylogic tool and analysis of evacuation time validated using SPSS. The results show that the placement of obstacles near the exit way indeed can reduce the evacuation time and complies with the anti-arching phenomenon during evacuation.