Dynamic Buffer Tank for CNG Fuel Supply Pulse Damping
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Solution Overview
Problem
Existing methods for producing high-pressure fuel gas for gas-fired diesel engines in LNG ships face challenges in absorbing gas pressure pulse fluctuations and providing high response pressure supply, particularly with reciprocating piston types, leading to difficulties in adjusting buffer tank volume and ensuring pressure responsiveness to diesel engine load fluctuations.
Innovation Solution
A fuel gas supply apparatus with a pressure-increasing means, a pressure adjustment valve, differential pressure measurement, and a buffer tank, where the discharge pressure is controlled based on load measurements to maintain optimal pressure and absorb pulsations, ensuring compatibility of pressure pulse absorption and response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a buffer tank is provided to absorb gas pressure pulse fluctuation, then gas pressure pulse absorption is improved, but pressure response to diesel engine load fluctuations deteriorates
Solution Approach 1:
The invention applies dynamics by making the buffer tank volume adjustable rather than fixed. The control unit dynamically changes the buffer tank volume based on real-time operating conditions (engine load, pressure fluctuations) to optimize both pressure absorption and response speed. When pressure pulses are severe, the buffer tank expands to absorb them; when rapid pressure response is needed, the buffer tank contracts to minimize its dampening effect.
Solution Approach 2:
The invention changes the volume parameter of the buffer tank dynamically. By adjusting the buffer tank volume according to operating conditions, the system can switch between two functional states: a larger volume for absorbing pressure pulses during steady operation, and a smaller volume for rapid pressure response during load changes. This parameter change resolves the contradiction between stability and speed.
2Stability of the object's composition
If buffer tank volume is increased to absorb pressure fluctuations, then pressure stability is improved, but adjustability for required pressure when load fluctuates deteriorates
Solution Approach 1:
The system transitions from a static buffer tank to a dynamic one whose volume can be adjusted in real-time. This allows the buffer tank to adapt its size according to engine load conditions, maintaining pressure stability when needed while enabling rapid pressure adjustment when the engine load changes.
Solution Approach 2:
The adjustable buffer tank serves multiple functions: it acts as a large-volume pressure stabilizer during steady operation, and as a small-volume responsive element during load transitions. This multi-functionality allows a single component to address both pressure stability and adaptability requirements.
3Use of energy by moving object
If a reciprocating piston type LNG liquid pump is used, then compression efficiency is improved, but gas pressure pulse fluctuation increases
Solution Approach 1:
The adjustable buffer tank acts as an intermediary between the reciprocating piston pump and the diesel engine. It absorbs the pressure pulses generated by the pump's reciprocating motion, smoothing out the fluctuations before the gas reaches the engine. The buffer tank mediates the conflict between the pump's efficient but pulsating output and the engine's requirement for stable pressure.
Solution Approach 2:
The buffer tank provides beforehand cushioning by being positioned between the pump and engine to absorb pressure pulses before they reach the engine. This prior cushioning prevents the harmful pressure fluctuations from affecting engine operation while maintaining the benefits of reciprocating piston compression.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively absorbs gas pressure pulse fluctuations and ensures high responsiveness of pressure supply to the diesel engine, preventing excessive pressure and maintaining efficient operation across varying load conditions.
Implementation Method 1
a buffer tank that is connected with the branch pipe and absorbs a variable pressure of the fuel gas in the main pipe caused by the pressure-increasing means
Implementation Method 2
a pressure adjustment valve that is provided on the upstream side of the pressure measurement means in the main pipe to adjust the pressure of the fuel gas whose pressure is increased by the pressure-increasing means to a set pressure according to the load of the gas fired diesel engine
Implementation Method 3
pressure-increasing means for increasing the pressure of fuel gas to be supplied to the gas fired diesel engine
Data Source
AI summary
A ship includes a main pipe that guides CNG whose pressure is increased by an LNG pump to the engine; a pressure sensor that measures the pressure of CNG to be supplied to the engine; a pressure adjustment valve that adjusts the pressure of the CNG to a set pressure according to engine load; a differential pressure sensor that measures a differential pressure before and after the pressure adjustment valve; and a buffer tank that absorbs a variable pressure of the CNG in the main pipe. The discharge pressure of the LNG pump is controlled such that the differential pressure is increased when the pressure is low, and the differential pressure is decreased when the pressure is high.