Extremely sophisticated emissions abatement systems are nowadays needed to meet the stringent limits imposed by environmental regulations, especially regarding NOx emissions for diesel vehicles and industrial thermal process such as power generation plants, combustion plants, thermal incinerators, cement, glass, petrochemical and other industrial sectors.
One of the most commonly used and effective one is the SCR after-treatment system (Selective Catalytic Reduction) which requires the use of Liquid Urea or AdBlue, a particularly valuable chemical, produced with technical urea and highly pure demi-water.
The high quality of this chemical is very important to prevent the potential damage of SCR system.
The transportation cost of this chemicals represents more than 50% of the final product cost and therefore the production should be as much diffused as possible in order to reduce the logistic cost.
For this reason, STC is proposing Urea dissolving plants for AdBlue production so that the environmental impact of the transport (traffic, fuel, CO2 and NOx emissions, possible accidents etc.) are largely reduced.
The plant is mainly composed of 3 sections:
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A) high purity water production plant:
Based on the experience in production of demineralized, pure and ultrapure water STC can design the water treatment plant for the selected capacity starting from any kind of water. The plant normally includes pretreatment, prefiltration, purification by membrane and/or EDI modules. The water treatment plants designed by STC are skid-mounted and fully automatic with total control by PLC with remote smart assistance.
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B) urea dissolving and mixing plant:
The granular/prilled urea of appropriate quality grade and the purified water are dosed carefully into a specifically designed dissolving system where a special propeller agitator ensures a fast and homogenous mixing in order to obtain a high purity solution with concentration in the range 25– 45% (adjustable according to the needs of the user). According to ISO 22241, technical norm 32,5% is the typical concentration required for diesel engines.
The granular/prilled urea can be fed from storage silos or from big bags with automatic emptying systems and weighing system.
Water must be appropriately heated up by means of heat exchangers that can use different kind of energy sources: depending on the local conditions, STC can design the water heating system with dedicated steam boilers, heat pumps, solar panels or through heat recovery form existing sources if any.
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C) AdBlue storage and bottling plant:
The produced solution of urea, granular urea, is then stored in one or more tanks and from the storage tanks the solution can be fed directly into the process plants through dosing pumps or alternatively can be pumped to cubitainer or canisters, or bottles fully automatic filling lines.
The STC systems are modular, easy to install and with a flexible production capacity and full automation system according to industry 4.0 concepts.
