Catalyst for HCl Oxidation and Chlorobenzene Incineration
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Solution Overview
Problem
The chlorine gas production process faces challenges due to low atomic utilization of chlorine resources, with by-products like hexachlorobenzene accumulating and disrupting the stability of hydrogen chloride oxidation, and existing catalysts either increase costs or fail to effectively convert chlorobenzene and o-dichlorobenzene.
Innovation Solution
A bi-functional catalyst comprising copper, manganese, boron, chromium, rare earth elements, potassium, titanium, phosphorus, and iron, supported by various carriers, which efficiently oxidizes hydrogen chloride and incinerates chlorobenzene or o-dichlorobenzene, preventing the formation of polychlorinated benzenes and maintaining process stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryogenic separation and adsorption with an adsorbent are used to reduce chlorobenzene content, then the stability of hydrogen chloride oxidation process is improved, but additional investment in fixed assets and operating costs increase
Solution Approach 1:
The patent extracts and removes the harmful chlorobenzene and o-dichlorobenzene impurities from the hydrogen chloride feed stream using an adsorption unit before the oxidation reactor. This prevents the impurities from entering the reactor and forming polychlorinated benzenes, thereby maintaining process stability without requiring expensive cryogenic separation equipment.
Solution Approach 2:
The patent introduces an adsorbent as an intermediary substance that selectively captures chlorobenzene and o-dichlorobenzene impurities from the hydrogen chloride stream. The adsorbent acts as a mediator between the impure feed and the oxidation reactor, removing harmful substances while allowing hydrogen chloride to pass through to the reactor.
2Productivity
If existing catalysts are used for hydrogen chloride oxidation, then chlorine gas is produced, but chlorobenzene and o-dichlorobenzene are converted to polychlorinated benzenes that accumulate and disrupt process stability
Solution Approach 1:
The patent performs preliminary removal of chlorobenzene and o-dichlorobenzene impurities through adsorption before the hydrogen chloride enters the oxidation reactor. This preliminary action prevents the formation of polychlorinated benzenes in the first place, eliminating the accumulation problem that would otherwise occur during chlorine gas production.
Solution Approach 2:
The patent converts the harmful effect of chlorobenzene and o-dichlorobenzene impurities from process disruptors into a manageable stream by using them as targets for selective adsorption. The adsorption unit specifically captures these harmful substances, transforming them from a source of problems into a controlled separation step that protects the oxidation process.
3Ease of manufacture
If chlorobenzene and o-dichlorobenzene are not removed before oxidation, then the cost of production is reduced, but polychlorinated benzenes accumulate in the heat exchanger and seriously disturb process stability
Solution Approach 1:
The patent introduces an adsorption unit with selective adsorbent as an intermediary step between the feed preparation and oxidation reactor. This intermediary unit specifically targets and removes chlorobenzene and o-dichlorobenzene impurities at low cost, preventing their conversion to polychlorinated benzenes while maintaining economical production.
Solution Approach 2:
The patent employs a cost-effective adsorption method using readily available adsorbents that can be regenerated or replaced economically. This approach provides an inexpensive solution to remove impurities compared to cryogenic separation, maintaining low production costs while ensuring process stability.
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 catalyst achieves a high conversion rate of hydrogen chloride to chlorine gas while effectively converting chlorobenzene and o-dichlorobenzene, reducing polychlorinated benzene accumulation and maintaining process stability with minimal cost increase.
Implementation Method 1
chlorine gas is prepared through the catalytic oxidation of hydrogen chloride
Implementation Method 2
catalytic oxidation of hydrogen chloride
Implementation Method 3
excellent ability to catalyze the incineration of chlorobenzene or o-dichlorobenzene
Implementation Method 4
catalytic combustion of chlorobenzene or o-dichlorobenzene
Implementation Method 5
can efficiently carry out catalytic incineration of chlorobenzene and/or o-dichlorobenzene while efficiently converting hydrogen chloride into chlorine gas
Data Source
AI summary
A catalyst for preparing chlorine gas by hydrogen chloride oxidation, comprising the following components calculated according to mass content based on the total weight of the catalyst: 0.5-20 wt% copper; 2-10 wt% manganese; 0.05-2 wt% boron; 0.01-3 wt% chromium; 0.1-10 wt% rare earth metal; 0.1-10 wt% potassium; and 3-15 wt% titanium; also comprising 0.02-1.1 wt% phosphorus; and 0.03-1.9 wt% iron; the carrier content is 55-90 wt%. In the case of a fluidized bed reactor, the present catalyst can achieve a one-way hydrogen chloride conversion rate of 80 - 85%. Almost all of the 0-1000 mg/kg of chlorinated benzene contained in hydrogen chloride gas can be converted into CO2 and H2O without generating polychlorinated benzene.