Gasification process for ammonia/urea production

Details Gasification process for ammonia/urea production Gasification process for ammonia/urea production

2001-05-07

2002-09-10

O'Sullivan, Peter (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Amino nitrogen containing

C564S069000, C564S070000, C564S072000

Reexamination Certificate

active

06448441

ABSTRACT:

BACKGROUND OF THE INVENTION
In the production of ammonia (NH
3
) and urea ((NH
2
)
2
CO), a syngas feedstream comprising hydrogen (H
2
) and carbon monoxide (CO) is first fed to a CO shift unit to convert CO to CO
2
, before being routed to an acid gas removal facility where the CO
2
is separated from the H
2
. The H
2
is then combined with nitrogen (N
2
) and fed to an ammonia synthesis unit. The CO
2
is then combined with a portion of the NH
3
product and fed to an urea synthesis unit. The primary reactions of this process are:
3H
2
+N2→2NH
3
(ammonia)  (1)
2NH
3
+CO
2
→(NH
2
)
2
CO (urea)+H
2
O  (2)
It is known to use gasification to produce the syngas feed to an ammonia/urea production facility. In the gasification process, hydrocarbonaceous material is partially oxidized in the presence of an oxygen rich gas and a temperature moderator at high temperatures. The syngas product of the gasification process primarily comprises H
2
and CO. There are many different types of hydrocarbonaceous material that can be fed to a gasification reactor, from natural gas to heavy oils and solid materials such as coal. Because natural gas has a lower C/H ratio than solid and liquid hydrocarbon materials, insufficient CO
2
is produced for urea production when a natural gas gasifier is used to produce syngas. Conversely, the high C/H ratio of solid and liquid hydrocarbon materials produces an excess amount of CO
2
-much more than is needed for urea production-and thus a large portion of the CO
2
is vented when only solid and/or liquid hydrocarbon materials are used to produce syngas. Thus, it would be beneficial to develop an integrated gasification and ammonia/urea production process that optimizes the CO
2
content of the syngas so as to maximize urea production. Furthermore, CO
2
is known to have an adverse effect on the environment, such as contributing to global warming, so it would also be desirable to minimize CO
2
venting in an integrated gasification/urea production facility.
SUMMARY OF THE INVENTION
The present invention involves a process for the co-production of ammonia and urea in which two parallel gasifiers are utilized so as to optimize the H
2
/CO
2
ratio in the combined syngas product, thereby maximizing the ammonia and urea production. In a first gasifier, solid and/or liquid hydrocarbon materials are partially oxidized in the presence of an oxygen-rich gas in the presence of a temperature moderator, thereby generating a first synthesis gas mixture comprising carbon monoxide, hydrogen and carbon dioxide. The oxygen-rich gas is normally extracted from air through an air separation unit (ASU). The by-product of the ASU, nitrogen (N
2
), is used in the downstream ammonia production unit.
In a second gasifier, natural gas is partially oxidized in the presence of an oxygen-rich gas, thereby generating a first synthesis gas mixture comprising carbon monoxide, hydrogen and carbon dioxide. By running two gasifiers in parallel on the separate feeds, the feedrates to each gasfier can be independently adjusted to optimize the H
2
/CO
2
ratio in the combined syngas product stream, thus maximizing ammonia and urea production and minimizing CO
2
emissions.
The combined syngas product stream is then processed in a CO shift reactor so as to convert any CO in the syngas into H
2
and CO
2
. The CO
2
is then removed from the syngas, usually along with H
2
S and any other sulfur components in an acid gas removal unit, leaving a substantially pure H
2
stream. The H
2
stream is then combined with N
2
from the air separation unit to form ammonia (NH
3
). The CO
2
recovered from a CO2 recovery unit is combined with at least a portion of the NH
3
product to form urea ((NH
2
)
2
CO).


REFERENCES:
patent: 4213957 (1980-07-01), Pinto
patent: 4524056 (1985-06-01), Banquy
patent: 4869887 (1989-09-01), Van Dijk
patent: 5900224 (1999-05-01), Fujimura et al.
patent: 5980858 (1999-11-01), Fujimura et al.
patent: 6063355 (2000-05-01), Fujimura et al.

Affiliated with

Also associated with

Rating

Gasification process for ammonia/urea production does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Gasification process for ammonia/urea production, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gasification process for ammonia/urea production will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2826004