Steam Heat Exchanger Condensation Control at Low pH
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Solution Overview
Problem
Conventional film-forming amines are not effectively adsorbed on heat transmission surfaces made of stainless steel or the like in steam systems at a low pH of less than 7, limiting the improvement of heat transmission efficiency.
Innovation Solution
The use of a sarcosine compound, particularly a long-chain sarcosine compound, is introduced in a steam system at a pH of less than 7, optionally combined with an emulsifier and/or neutralizing amine, to promote drop-wise condensation and enhance heat transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional film-forming amines are used in steam systems at low pH, then drop-wise condensation can be achieved, but the amines are not adsorbed on stainless steel surfaces at pH less than 7, limiting heat transmission efficiency improvement
Solution Approach 1:
The patent changes the chemical structure parameter of the film-forming agent from conventional amines to sarcosine compounds with specific molecular structure (N-alkyl-N-methylamino group combined with hydrocarbon chain). This structural parameter change enables effective adsorption on stainless steel surfaces at low pH conditions where conventional amines fail, while maintaining drop-wise condensation functionality and heat transmission efficiency improvement
Solution Approach 2:
The patent creates a composite protective film on metal surfaces by combining sarcosine compounds that can simultaneously provide both adsorption stability on stainless steel at low pH and hydrophobic bonding properties for drop-wise condensation. This composite functional layer resolves the contradiction between adsorption reliability and heat transmission efficiency
2Productivity
If film-wise condensation occurs, then steam contacts metal surfaces continuously, but the heat transfer coefficient is low requiring larger heat exchange areas
Solution Approach 1:
The patent introduces sarcosine compounds as intermediary substances that adsorb on metal surfaces to form a protective film layer. This intermediary layer modifies the condensation mode from film-wise to drop-wise by preventing continuous liquid film formation, thereby significantly increasing the heat transfer coefficient and enabling the use of smaller heat exchange areas
Solution Approach 2:
The patent utilizes the phase transition behavior of condensate liquid on the sarcosine-modified surface. The protective film causes condensate to form discrete droplets that periodically coalesce and fall, creating dynamic phase transition cycles that maintain higher heat transfer coefficients compared to continuous film-wise condensation
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 sarcosine compound effectively suppresses condensation water film formation, enhancing heat transmission efficiency and reducing steam usage, facilitating downsizing of facilities and improving productivity without large-scale renewal, especially in systems with stainless steel surfaces.
Implementation Method 1
a sarcosine compound is allowed to be present in a steam system... the sarcosine compound is stably adsorbed on a metal surface
Implementation Method 2
contacting the steam with a cooling body to liquefy the steam... drop-wise condensation, in which condensate liquid turns into many droplets
Implementation Method 3
adheres stably to the metal surfaces by hydrophobic bonding to form protective film layers (anticorrosive films), resulting in the prevention of the contact between the metal and water
Implementation Method 4
ionically bound to the metal surfaces mutually, and adheres stably to the metal surfaces
Data Source
AI summary
Provided is a method for improving efficiency of heat transmission that enables improving the efficiency of heat transmission by steam in a steam system at a pH of less than 7. A method for improving the efficiency of heat transmission by steam, wherein, in a step of introducing steam into a heat exchanger to heat an object to be heated or a step of contacting the steam with a cooling body to liquefy the steam, a sarcosine compound is allowed to be present in the steam system at a pH of less than 7. As the sarcosine compound, a long-chain sarcosine compound represented by the following formula (I) is preferable. R1C(═O)—N(CH3)—(CH2)n—COOR2 . . . (I) In formula (I), R1 is an unsaturated or saturated linear or branched hydrocarbon group having 7 to 24 carbon atoms, n is an integer of 0 to 2, and R2 is a hydrogen atom or a salt-forming group.