Polyisocyanate Production System Hydrochloric Gas Control
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Solution Overview
Problem
The polyisocyanate production process faces instability due to variations in hydrochloric gas production, which affects the steady supply required for chlorine production and the stability of the isocyanate reaction, and there are challenges in effectively treating hydrochloric gas, especially when issues arise in the oxidation tank or detoxification column.
Innovation Solution
A polyisocyanate production system that includes a hydrogen chloride purifying unit, a chlorine producing unit, a hydrochloric acid producing unit, and control units to regulate the supply and pressure of hydrogen chloride, ensuring steady chlorine production and effective treatment of hydrochloric gas, with a gas treatment apparatus using gravity-driven treatment liquid supply to maintain gas-liquid contact even in power source interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrochloric gas is oxidized to produce chlorine, then chlorine production is achieved, but the process becomes unstable when hydrochloric gas production varies
Solution Approach 1:
The invention changes the operational parameters by introducing a bypass line that allows flexible routing of hydrochloric gas between the oxidation tank and detoxification column. This enables the system to adapt to varying hydrochloric gas production rates, maintaining stable chlorine production while preventing overflow or pressure buildup that would compromise reliability.
Solution Approach 2:
The control unit acts as an intermediary that monitors hydrochloric gas flow and automatically adjusts the bypass valve to regulate gas distribution. This intermediary control mechanism ensures stable chlorine production by preventing excessive gas accumulation in the oxidation tank while maintaining adequate supply for chlorine generation.
2Reliability
If hydrochloric gas is treated in the detoxification column, then gas treatment is achieved, but the system becomes vulnerable when the oxidation tank malfunctions
Solution Approach 1:
The invention segments the gas treatment system into two independent pathways: the oxidation tank for chlorine production and the detoxification column for gas treatment. The bypass line connects these segments, allowing the system to isolate and operate one component independently when the other malfunctions, thereby maintaining both treatment effectiveness and system flexibility.
Solution Approach 2:
The bypass line is pre-configured and ready for immediate use, allowing hydrochloric gas to be redirected to the detoxification column before an oxidation tank malfunction fully impacts the system. This preliminary preparation ensures continuous gas treatment capability and prevents system-wide failures.
3Reliability
If treatment liquid is supplied using a pump, then gas-liquid contact is achieved, but the system fails when power source is interrupted
Solution Approach 1:
The invention replaces the pump-based treatment liquid supply system with a gravity-driven system where the treatment liquid storage tank is positioned at a higher elevation than the gas-liquid contact chamber. This self-service mechanism uses gravitational force to automatically supply treatment liquid, eliminating the need for external power sources while maintaining reliable gas-liquid contact efficiency.
4Ease of operation
If the treatment liquid storage tank is positioned high, then gravity-driven supply is achieved, but the device complexity increases
Solution Approach 1:
The invention applies the principle of equipotentiality by positioning the treatment liquid storage tank at a higher gravitational potential than the gas-liquid contact chamber. This elevation difference creates a natural potential energy gradient that drives treatment liquid flow without requiring mechanical pumps or complex control systems, thereby achieving power source independence while minimizing structural complexity.
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
This system ensures stable chlorine production and effective treatment of hydrochloric gas, maintaining constant inner pressures and efficient gas-liquid contact, enhancing the safety and reliability of the polyisocyanate production process.
Implementation Method 1
a gas treatment apparatus using gravity-driven treatment liquid supply to maintain gas-liquid contact even in power source interruptions
Implementation Method 2
a chlorine producing unit to which the hydrogen chloride purified in the hydrogen chloride purifying unit is supplied and in which the hydrogen chloride is oxidized to produce the chlorine
Implementation Method 3
a hydrochloric acid producing unit to which the hydrogen chloride purified in the hydrogen chloride purifying unit is supplied and in which the hydrogen chloride is absorbed in water to produce a hydrochloric acid
Data Source
AI summary
A polyisocyanate production system is provided that can stably produce chlorine from hydrogen chloride produced secondarily while reacting stably between carbonyl chloride and polyamine and can perform an effective treatment of the hydrochloric gas produced secondarily. A hydrochloric gas control unit 32 controls a flow-rate control valve 23 to keep constant an amount of hydrogen chloride supplied from a hydrogen chloride purifying tank 4 to a hydrogen chloride oxidation reactor 6 via a second hydrochloric-gas connection line 11 to be constant, and also controls a pressure control valve 22 based on an inner pressure of the hydrogen chloride purifying tank 4 input from a pressure sensor 25 to discharge the hydrochloric gas from the hydrogen chloride purifying tank 4 to the hydrogen chloride absorbing column 5 via a first hydrochloric-gas connection line 10, so as to keep an inner pressure of the hydrogen chloride purifying tank 4 to be constant.