Refining Processes Handbook - 2020 - 313

2020 REFINING PROCESSES HANDBOOK
PROCESS CATEGORIES

COMPANY INDEX

RESIDUES

Residue gasification
for H2 and CO production

Flue gas

Application: Production of hydrogen (H2) and/or carbon monoxide (CO) from heavy
hydrocarbons is a key technology for refineries to develop an economic and efficient
bottom-of-the-barrel strategy.

Oil/residue

Description: The most common "refinery residues" are vacuum tower bottom and
visbreaker residues, high aromatic fraction from solvent-deasphalting units and
petcoke from cokers. A wide range of feedstock composition and characteristics
result from these different upstream processes and are covered by the term "refinery
residue." Some of the residues are solid at ambient temperature and others are liquid
under these conditions. Typically, the specifications show high sulfur content, high
metal content and high viscosities.
The core unit of a gasification plant is the partial oxidation reactor. In this reactor,
the feedstock is converted by means of sub-stoichiometric addition of oxygen into a
carbon oxide and H2-rich raw synthesis gas. The conversion takes place typically at
40 bara-100 bara and approximately 1,400°C (2,552°F). The design and operation
of the gasification plant requires a robust custom-made design to cope with the
specific properties of the various feedstocks and the required syngas products. The
high-temperature conditions are challenging with respect to process and equipment
design. Therefore, the proper selection and design of the gasifier and adjacent
systems are crucial.
The feed system is required for the conditioning of the residue to ensure reliable
and steady injection into the partial oxidation. The reactor concepts and operating
conditions are individually adapted to achieve high feedstock conversion and process
reliability and availability. Auxiliary systems (e.g., the soot water system) and raw gas
cooling and scrubbing are required to minimize effluents, recover heat and to supply
the raw gas pre-conditioned to the subsequent syngas processing units.
The raw syngas can be converted to pure H2, synthesis gas/oxogas, CO or simply
to fuel gas. The basic process steps for H2 production include syngas cooling, CO
shift, acid gas removal and pressure swing adsorption for the final H2 purification.
A sulfur recovery unit (SRU) is typically required for the processing of various acid
gases streams from the black water treatment and the acid gas removal.
For additional production of CO, the plant scheme is extended by temperature
swing adsorption and cryogenic gas separation. The CO shift is no longer required
when CO content shall be maximized.

CO2

Sup. HP export steam

Steam system
package boiler
HP steam

LP steam

Soot water
Soot oil

BFW
treatment

Preheated
demineralized
water

Cond.
recycle

Soot
recovery

Process
condensate

Syngas
cooling

CO2

Acid gas
removal II

Oxygen
Utilities and offsite facilities

NH3

Nitrogen
wash unit
Flash gas/
fuel gas

Temperature
swing
adsorption
Enriched
raw H2

Wastewater

LP nitrogen
HP nitrogen

Temperature
swing
adsorption

Common
solvent
regeneration

Oil

Air
separation

Ammonia
synthesis

Fuel
gas
Acid gas
removal I

Tailgas

Sulfur

Sulfur
recovery

BFW

shift and
syngas
cooling

Partial
oxidation

Feed system

Demineralized
water import

Cryogenic
condensation
process

CO

Pressure
swing
adsorption

H2

Non
Raw H2 permeate
Mem
bra
ne Syngas/
oxogas

Fuel gas

A residue partial oxidation plant can also serve as a gas generation unit
for downstream production of base chemicals and fertilizers (e.g., ammonia,
UREA or methanol) and even for combinations of these.

Products: H2 and CO are the two main components of synthesis gas, the major
building block of the entire C1 chemistry. Further products that are immediately
obtainable from synthesis gas range from bulk chemicals, such as ammonia (NH3)
and methanol (CH3OH) through Fischer-Tropsch products to oxo-alcohols and
industrial gases. Additional byproducts include carbon dioxide (CO2), sulfur and steam.
Continued 
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Refining Processes Handbook - 2020

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