Apr-2023

Fertiliser can also help your refinery grow revenue

Energy companies under pressure. The global Environmental, Social and Governance (ESG) movement is having an enormous impact on how energy companies are managed, measured, and operated. It is observed throughout the oil & gas industry, that many companies are setting ambitious sustainability goals to achieve carbon neutrality in the near future. Innovation in process technologies and process optimisation will be key to achieving that goal.

Janet Ruettiger, Elizabeth Jensen and Michael Penninger
Honeywell UOP

Article Summary

The regulatory environment has been a primary driver in the industry’s migration toward more sustainable operations. Many jurisdictions worldwide are turning up the pressure on oil and gas producers to reduce emissions of contaminants including SOX and NOX and greenhouse gases (GHG).

Customers, and shareholders, have also influenced oil and gas producers to pursue a greener agenda. Research shows, that the majority of the population are more likely to do business with and/ or buy products from companies that are socially responsible.

Refiners have several options to achieve their sustainability targets, including:
• Carbon capture & sequestration
• Technology updates that improve efficiency
• Use of renewable feedstocks
• Updates to waste stream management (achieve more stringent emission limits)

For some refiners, government incentives such credits and tax incentives can help offset the cost of implementing greener solutions. However, in many cases sustainability targets are mandated and come at a cost to the refiner.

Conventional hydroprocessing waste management
As environmental regulations continually evolve while global demand of fuels and petrochemical products change, refiners are perpetually optimising to protect profit margins / satisfy market needs. Hydroprocessing units remove sulphur and nitrogen from feedstocks to produce clean fuel and feedstocks for petrochemical processes. These units are turning to increases in throughput and use of opportunity feedstocks to increase profitability. The impact of aforementioned changes, increase waste, which can strain existing waste management assets and limit optimisation.

As environmental regulations continually evolve while global demand of fuels and petrochemical products change, refiners are perpetually optimising to protect profit margins / satisfy market needs. Hydroprocessing units remove sulphur and nitrogen from feedstocks to produce clean fuel and feedstocks for petrochemical processes. These units are turning to increases in throughput and use of opportunity feedstocks to increase profitability. The impact of aforementioned changes, increase waste, which can strain existing waste management assets and limit optimisation.

The conventional hydroprocessing waste treatment (Figure 1) utilises a sulphur recovery unit (SRU) and a tail gas treating unit (TGTU) to convert H₂S to elemental sulphur. From these processes the elemental sulphur is collected and can be sold as a commodity. Typically, NH₃ waste is converted to NOX or N₂ and released to the atmosphere at no value.

The proprietary nViro Hydro solution (Figure 2) from Honeywell’s UOP business provides an alternate solution for refineries installing new hydroprocessing capacity or updating their existing assets. Compared to the conventional process in (Figure 1), the nViro Hydro process improves operational efficiency, creates a new revenue stream, and reduces capital outlays, operating expenses, and water use.

Honeywell UOP solution – nViro Hydro
The proprietary nViro Hydro solution (Figure 2) tackles hydroprocessing waste treatment by upgrading the main waste products hydrogen sulphide (H₂S) and ammonia (NH₃) into a combination of ammonium sulphate ((NH₄)₂SO₄ ,or AS for short), and elemental sulphur. Ammonium sulphate is a common ingredient in multi-nutrient NPKS (nitrogen, phosphorus, potassium & sulphur) fertiliser blends. This solution not only cleans the waste stream to meet emission requirements, but also boosts the economic returns.

The produced ammonium sulphate can be sold directly as a powdered material, or if desired an additional compaction step can be added to the nViro Hydro process which may increase the value of the ammonium sulphate and/or make the product more marketable.

From an environmental standpoint, the primary benefit of the nViro Hydro process is removing pollutants such as H₂S, NH₃, NOX, or SOX from hydroprocessing effluent streams to avoid their release to the environment and meet emission specifications. nViro Hydro also boasts reduced Scope 2 carbon dioxide (CO₂) emissions through improved heat integration and reduced utility requirements relative to the conventional system.

From an economic standpoint, the benefits include capital expenditure and operational cost reductions compared to conventional treatment. This can significantly improve the net present value (NPV) for refineries adding capacity or updating their current capabilities.

Key advantages of nViro Hydro
• Upgrade waste stream into a marketable AS fertiliser product
• Increases energy recovery
• Lower capital expenditures through reduction in or removal of key equipment
• Lower operating expenditures through improved energy efficiency
• Debottlenecking of existing SRU capacity removes pollutants (H₂S, NH₃, NOX, SOX, etc…) from hydroprocessing effluent streams
• Reduces carbon dioxide (CO₂) Scope 2 emissions through improved heat integration and reduced utility requirements
• Nearly eliminates water utility
• Significantly decreases wastewater treatment requirements

The nViro hydro solution delivers improved financial, operational, and environmental outcomes for both revamps and new unit installations, as described in Case studies A and B.

Case studies
Case A - New hydrocracking unit
An oil and gas company building a new hydrocracking unit at one of its existing refineries. The unit is designed to process up to 50,000 barrels of vacuum gasoil (VGO) per stream day. The VGO has a sulphur content of 2.6% and a nitrogen content of 1,300 parts per million by weight. Building the system with nViro Hydro instead of a conventional waste handling system will deliver significant financial benefits, including: adding capacity or updating their current capabilities.