Expert advice and best practices for CNG and LNG plants

Recommended power supply system for CNG/LNG plants

i．CNG and LNG gas power plants - configuration solutions

Taking a 100,000 ton LNG liquid plant as an example, this solution adopts: separator + pressure reducer + buffer tank + 4 sets 1000kW (400V) skid-mounted silent gas generator sets + parallel-connection distribution cabinet to power the liquid plant. 

The parallel-connection distribution cabinet is equipped with a box-type transformer, which provides power to the high-voltage equipment in the liquid plant through the distribution cabinet. 

The design process of the solution is shown in the figure on the right:

ii．Purpose:Continuous stability, high efficiency and energy saving.

iii．Requirements

1. Energy requirements: meet the normal power demand of NG plant power equipment, meet the normal loading process of NG equipment, run for a long time for 24 hours after startup without power outage, and quickly start the standby unit to complete the switch when the unit fails.

2. Hoisting requirements: The product design is easy to hoist and relocate, strengthen the structural design, and multiple hoisting will not cause product deformation.

3. Use environment requirements: The product design meets the normal use under conditions of high temperature, high humidity, high altitude and environmental noise.

4. Layout requirements: Meet the requirements of product safety spacing, maintenance, etc., the product is compact and reasonable; meet the direction of the on-site pipeline line, and the installation layout is neat and uniform.

iv．NG Load Analysis

In order to meet the power load requirements of NG production equipment and better match the gas generator set, a normal working load situation investigation and analysis was conducted taking a 100,000 cubic meter LNG liquid plant as an example. 

The results are shown in the following table：

 v．Program Features

1. Convenience of equipment combination: In view of the energy consumption and environmental characteristics of NG equipment, power generation equipment can be arranged on-site in modular open and skid-mounted styles. 

    Open units are used in places with low noise requirements, and operation and maintenance are convenient and quick. Skid-mounted units adopt a silent design and are suitable for places with noise requirements.

2. Ease of operation: With intelligent centralized control, the unit realizes one-button start, parallel closing, load distribution, opening, shutdown and other functions, and is equipped with automatic start and stop equipment for unit power management, and can be configured with remote monitoring.

3. Environmental adaptability: The unit optimizes its functions according to the actual use environment and can better adapt to high temperature, high humidity, low temperature, high altitude and other environments.

4. Transient responsiveness: When the power load changes suddenly, the engine responds quickly to reduce the impact of transient load changes on frequency and voltage.

5. Operation economy: The domestic mass-produced engine is used, with low failure rate, simple maintenance, low cost, and optimized calibration according to the gas source composition, which is more economical.