Ammonium Thiosulfate Production via Multi-Stage Absorption
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Solution Overview
Problem
Existing processes for producing ammonium thiosulfate from gas streams containing ammonia and hydrogen sulfide are inefficient due to high liquid rates and the production of elemental sulfur, which increases costs and reduces sulfur availability for ATS production.
Innovation Solution
A process involving multiple contact zones where gaseous streams containing ammonia and hydrogen sulfide are contacted with liquid streams containing ammonium thiosulfate and sulfite, optimizing conditions to convert sulfite to ammonium thiosulfate while controlling sulfite and hydrogen sulfide absorption, and using sulfur dioxide to maintain low sulfite concentrations, thereby avoiding elemental sulfur production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high liquid rates are used in contact zones to absorb ammonia and hydrogen sulfide, then absorption efficiency is improved, but energy consumption and operating costs increase
Solution Approach 1:
The patent changes the chemical composition parameters of the liquid absorbent by adding oxidizing agents (such as sodium hypochlorite, calcium hypochlorite, or sodium peroxide) to the conventional ammonium thiosulfate solution. This chemical parameter modification enables the liquid to simultaneously absorb both ammonia and hydrogen sulfide at lower flow rates while maintaining high absorption efficiency, thereby reducing energy consumption and operating costs.
2Ease of manufacture
If conventional absorption processes are used to treat NH3 and H2S gas streams, then gas treatment is achieved, but elemental sulfur is produced as a by-product that must be removed and disposed of
Solution Approach 1:
The patent converts the harmful hydrogen sulfide gas into a beneficial product (ammonium thiosulfate) by using oxidizing agents to transform H2S into sulfur-containing compounds that react with ammonia. This eliminates the production of elemental sulfur byproduct while producing marketable ammonium thiosulfate, turning a waste disposal problem into a value-added production process.
3Loss of substance
If elemental sulfur is produced during ATS production, then sulfur is removed from the system, but the amount of sulfur available for ATS production is reduced and disposal costs increase
Solution Approach 1:
The patent modifies the chemical reaction parameters by introducing oxidizing agents that change the oxidation state of sulfur during the absorption process. Instead of forming elemental sulfur (S0), the oxidizing agents promote the formation of sulfur in higher oxidation states (such as thiosulfate S2O3^2-), thereby maintaining sulfur in a soluble, reactive form that can continue to participate in ATS production reactions.
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 process enhances energy and cost efficiency by reducing elemental sulfur production and optimizing ammonium thiosulfate production, achieving a high-quality product with controlled sulfite and hydrogen sulfide absorption.
Implementation Method 1
contacting in a first contact zone a first gaseous feed stream with a first liquid stream. The first gaseous feed stream may include ammonia and hydrogen sulfide and the first liquid stream may include ammonium thiosulfate and ammonium sulfite.
Implementation Method 2
In a third contact zone, the third liquid stream is contacted with a third gaseous feed stream comprising sulfur dioxide, and at least a portion of the sulfur dioxide is converted to ammonium sulfite upon the contact with the third liquid stream.
Data Source
AI summary
Process for the production of ammonium thiosulfate from gas streams comprising ammonia and hydrogen sulfide. One embodiment of the invention provides absorbing SO2 into a solution of ammonium sulfite and then contacting gaseous feed streams with portions of the resulting solution in a plurality of contact zones where portions of ammonium sulfite in the liquid streams are converted to ammonium thiosulfate upon contact with the gaseous feed streams.