Refining

Improving carbon balance through cleaner processes and products that release fewer emissions.

Oxygen enrichment in Fluid Catalic Cracking 

Fluid catalytic cracking (FCC) converts primarily vacuum gas oil from the crude distillation unit into gasoline blending stocks and fuel oils.
FCC breaks down heavier and more complex hydrocarbons into lighter ones. Feed is primarily vacuum gas oil, often mixed with refinery residues.
The main products are: 
•    Gas fraction (mainly C3/C4)
•    Liquid fraction
•    Coke (solid formation on the catalyst). 

Oxygen enrichment in the regeneration allows the refinery operator to: 

•    increase the FCC capacity
•    get higher flexibility in the choice of feeds
•    use heavier feeds
•    raise the conversion and the petrolium yield
•    reduce by-products.

Gas/Liquid Reactions 

Industrial gases like oxygen, hydrogen, carbon monoxide and carbon dioxide are widely used for synthetic processes in the chemical industry
We have designed a modular, multifunctional stirred reactor test plant (CSTR) for the investigation of a large number of homogeneous gas/liquid reactions.
The test plant shown in the picture is perfectly suited for verification of preliminary laboratory results as well as scale-up to medium or large sized technical plants.
Gaseous oxygen is used in many gas/liquid oxidations, for example, in production of hydroperoxides, the oxidative decarboxylations or oxidation of toluene derivatives. Two oxygen applications could be considered for oxidation processes, oxygen enrichment of oxidation air and total substitution of air by oxygen.

The benefits of these applications include:

•    Increased throughput and selectivity
•    Same conversion rate at lower temperatures
•    Savings in total operating costs. 

Linde provides a number of service options, these include; feasability and profitability studies, test runs with our stirred reactor test plant, process calculations to evaluate the effects, supply and installation of gas mixing units and the installation and start-up of oxygen supply systems.

Oxygen for Heterogenous Oxidations

 Improving plant capacity and flexibility
Oxidations performed in the heterogeneous gas phase of fixed or fluidized bed reactors are widely used for production of bulk chemicals.
Molecular oxygen is the predominant oxidative agent used in these reaction steps. Dependent on the applied process either; air (e. g. for production of maleic or phthalic anhydride), oxygen enriched air (e. g. for production of acrylonitrile) or pure oxygen (e. g. for production of vinylacetate) can be used as a gaseous oxidant.

Fluidized bed oxidations are often operated by means of oxidation air, because of its high nitrogen content, it provides an effective fluidizing gas stream for solid particles.

The addition of pure oxygen to the oxidation air or the direct oxygen injection into the reactor can reveal considerable benefits to the customer:
•    Higher plant capacity
•    Backup of air compression
•    Relief of waste gas treatment
•    Enhanced flexibility of plant operation.

In addition, the realization of such an oxygen system comes along with remarkable low investment costs.
We offer the optimum solution regarding process knowledge, equipment and gas supply systems.

Hydrogen Applications in Refineries

Demand for hydrogen will increase in the upcoming years as a result of stricter environmental legislation. Not only legislation but more extensive processing of residues and higher diesel demand compared with petrol will also increase hydrogen's demand.

There are various hydrotreating processes in a refinery. To name a few:
•    Hydrodesulphurisation: sulphur compounds are hydrogenated to hydrogen sulphide H2S as feed for Claus plants
•    Hydroisomerisation: normal paraffins are converted into iso-paraffins to improve the product properties (e.g. RON)
•    Dearomatisation: aromatics are hydrogenated to cyclopa-raffins or alkanes
•    Hydrocracking: long-chain hydrocarbons are cracked to shorter chains in the gasoline range.

Hydrogen volumes consumed increasingly exceed those produced in a platformer and have to be supplemented by other sources.

Main processes for hydrogen on-site supply:
•    Steam reforming of methane or other hydrocarbons
•    Recovery from refinery off-gases
•    Recovery from syngas
•    Gasification of oil refining residues.

Process consulting, financing, erection and start-up are all services offered by Linde.  We can also provide Hydrogen plant operation (over-the-fence-supply), maintenance and repair  and emergency supply arrangement to ensure that your business is working at it's optimum.

Oxygen enrichment in Claus plants

Oxygen enrichment (O2e) of the process air is a proven, flexible way to debottleneck operations while increasing flexibility. As air is approximately 79% nitrogen and 21% oxygen, the use of air to supply the oxygen for combustion of H2S to SO2 also introduces a large quantity of nitrogen, which has to be heated and does not contribute to the reaction. If air is replaced with oxygen-enriched air or pure oxygen, this eliminates the nitrogen ballast, also reducing the volume flow through the sulfur recovery unit (SRU). This means more acid gas can be fed into the system without the need for significant modifications to existing equipment or major changes to the process plant pressure profile.

Benefits of oxygen enrichment in Claus plants
•    Increased sulfur handling capacity and removal of bottlenecks
•    Increased productivity without changing the pressure drop
•    Greater flexibility to handle a wider operating envelope with the option to modify process intensification on demand
•    More effective treatment of ammonia-containing feeds
•    Less effort for tail gas purification (reduced nitrogen flow)
•    Greater redundancy – especially with multi-train systems

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