Ammonia Desulfurization Offers Coke Plants a New Way to Reduce Operating Costs

Many coke plants recover ammonia during coke oven gas purification while continuing to purchase limestone for flue gas desulfurization. As gypsum disposal expenses and carbon costs increase, this traditional separation between ammonia recovery and FGD operation is becoming increasingly difficult to justify.

Ammonia recovered through the ammonia-stripping process can typically be converted into ammonia water with a concentration of around 5%–10%, which can serve as an absorbent in an ammonia-based FGD system.

During desulfurization, sulfur dioxide reacts with ammonia to form ammonium sulfite. Through oxidation, concentration and crystallization, the solution is converted into ammonium sulfate fertilizer. Unreacted ammonia can also be recovered and used as a reducing agent in a selective catalytic reduction (SCR) denitrification system, creating opportunities for integrated ammonia utilization.

This approach offers an alternative to the conventional limestone-gypsum process. Calcium-based desulfurization generates gypsum that requires compliant disposal and is associated with additional carbon emissions. Ammonia desulfurization, by contrast, can convert recovered plant ammonia into a useful absorbent while producing ammonium sulfate as a potential revenue-generating by-product.

The market provides an important outlet for this product. In September 2026, mainstream coke-grade ammonium sulfate prices reportedly recovered to RMB 963–1,015 per tonne in Shanxi, following fluctuations after the introduction of new export inspection requirements in July.

MirShine Group has worked with a coke producer in Hebei on an ammonia-based FGD project using a fiberglass-reinforced plastic (FRP) desulfurization tower. The project responds to regional air pollution control requirements and demonstrates how ammonia recovery can be connected with flue gas treatment.

For coke plants, ammonia desulfurization is not simply a change in absorbent. It provides an opportunity to connect ammonia recovery, sulfur dioxide removal, denitrification and ammonium sulfate production into a more integrated resource utilization system.