Ammonia Salt Treatment Case Study

ProDecon® was asked by a refinery in United Kingdom to decontaminate the fuel gas header feeding one of their furnaces. The header developed flow restrictions due to the accumulation of ammonia salts deposition. The deposits had developed to a point where it may have been necessary to instigate a unit shutdown, just to clear this as the furnace was performing well below the desired operating range.

ProDecon® suggested the use of its ACF™ chemistry which is proven to be very effective in ammonia salts removal. The chemical was introduced into the main fuel gas header upstream of the furnaces and downstream of the knockout drum. Due to the piping configuration in this case, nitrogen was used as a carrier gas to help atomise the chemical into the fuel gas flow. The quantity of nitrogen was calculated beforehand and maintained more than 50% below the maximum nitrogen flow which could be safely introduced into the fuel gas stream without risking furnace performance. Whilst nitrogen was used in this case other alternatives can be used, and depending on the actual available injection point and flow parameters, a carrier gas may not be necessary.

Utilising ACF™ chemistry and its experienced personnel, ProDecon® was able to complete the decontamination of the fuel gas header in one shift, including rigging up of the injection equipment. The ammonia salts deposits were upstream of the PCV feeding the last furnace on the system. The graph shows the fuel gas flow, the pressure on the line downstream of the PCV and the valve position.

As we can see from the graph, before the decontamination the PCV was 100% open and the maximum flow rate was 134Nm3/hr with pressure of 0.96barg. The immediate change in flow and pressure is obvious when the chemical injection started. Also, we can see the change in valve position for the control of the flow rate. After the decontamination, stable conditions were achieved with flow rate of 363Nm3/hr and pressure of 1.31barg with the PCV just 64% open. Halfway through the decontamination the client was bringing additional burners online and tripping out the furnace for testing purposes, hence, the fluctuations during this period.

Customer Verified results

ProDecon® successfully completed this project within a very short period of time, within one shift the rigging up of the chemical injection equipment and the decontamination were completed. The shutdown was avoided and the furnace was kept online during the decontamination with no impact from the chemical injection. The system was reported to be restored to its full operating capacity.

ProDecon® – Cutting Edge Performance Restoration , keeping your plant on-line.