Feedwater Preheater Control for Low-Loss Boiler Operation
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Solution Overview
Problem
Conventional boiler systems face inefficiencies in heat radiation loss and boiler efficiency due to the arrangement of heat exchangers in feedwater preheaters, which affects the control of combustion amounts and thermal energy utilization.
Innovation Solution
A boiler system with a feedwater preheater having a heat exchanger on a descendant passage of the discharge passage, where the feedwater is preheated using residual combustion gas heat, and a combustion amount control mechanism that adjusts the number of boilers and combustion rates based on feedwater temperature thresholds to minimize heat radiation loss and maximize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a feedwater preheater with heat exchanger is disposed on a descendant passage to recover latent heat, then boiler efficiency is improved, but heat radiation loss increases
Solution Approach 1:
The invention changes the operational parameters by introducing feedwater temperature threshold values and corresponding combustion amount ratios. The combustion amount control means adjusts the combustion amount based on measured feedwater temperature, selecting from multiple predetermined combustion amount ratios (e.g., 30%, 60%, 90% of rated combustion amount) to optimize the balance between heat radiation loss and boiler efficiency.
Solution Approach 2:
The invention implements a feedback control mechanism where the combustion amount control means continuously measures feedwater temperature and adjusts the combustion amount accordingly. The control means compares measured feedwater temperature against threshold values and automatically selects appropriate combustion amount ratios, creating a closed-loop control system that dynamically optimizes boiler operation.
2Productivity
If combustion amount is increased to compensate for heat radiation loss, then boiler efficiency decreases, but steam production increases
Solution Approach 1:
The invention makes the combustion amount dynamic rather than fixed. The combustion amount control means continuously adjusts the combustion amount ratio based on real-time feedwater temperature measurements, allowing the system to adapt to changing operating conditions. This dynamic adjustment enables optimal balance between steam production and energy efficiency under varying load conditions.
Solution Approach 2:
The invention uses predetermined combustion amount ratios that represent partial combustion levels (e.g., 30%, 60%, 90% of rated combustion amount). Instead of always operating at full combustion capacity, the system selects appropriate partial combustion levels based on feedwater temperature, avoiding excessive combustion when not needed and thereby reducing heat radiation loss while maintaining adequate steam production.
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 system reduces heat radiation loss to 1% or less and enhances boiler efficiency to 96% or more by optimizing combustion amounts and feedwater preheating, improving thermal energy utilization and operational efficiency.
Implementation Method 1
a feedwater preheater including a heat exchanger which is provided on the passage, for allowing feedwater supplied to the boiler body to flow therethrough, and supplying the feedwater to the boiler body after the feedwater is previously heated in the heat exchanger with the combustion gas flowing on the passage
Implementation Method 2
condensed water (i.e., drained water) flows in the same direction as that of the descending combustion gas, and thus, the recovery effect of latent heat can be improved by a condensation effect
Implementation Method 3
a boiler body in which combustion is carried out
Implementation Method 4
minimizing the combustion amount in the boiler in the case where the feedwater temperature measured by the feedwater temperature measuring means is the feedwater temperature threshold or lower
Data Source
AI summary
A boiler system has a boiler and a combustion amount control unit. The boiler includes a boiler body, a discharge unit, a discharge passage, a feedwater preheater and a feedwater temperature measuring unit. The feedwater preheater includes a heat exchanger. The feedwater temperature measuring unit measures a feedwater temperature that is the temperature of the feedwater flowing in the heat exchanger. The combustion amount control unit controls combustion amount in the boiler, and has a feedwater temperature threshold as a threshold relating to the feedwater temperature. The combustion amount control unit minimizes the combustion amount in the boiler in a case where the feedwater temperature measured by the feedwater temperature measuring unit is the feedwater temperature threshold or lower.