Great research starts with great data.

Learn More
More >
Patent Analysis of

Process for generation of synthesis gas by flue gas recycle

Updated Time 12 June 2019

Patent Registration Data

Publication Number

US10150670

Application Number

US15/527202

Application Date

25 November 2015

Publication Date

11 December 2018

Current Assignee

HALDOR TOPSØE A/S

Original Assignee (Applicant)

HALDOR TOPSOE A/S

International Classification

C01B3/48,C01B3/34,C01C1/04

Cooperative Classification

C01B3/48,C01B3/34,C01C1/0488,C01B2203/0233,C01B2203/0238

Inventor

ANDERSEN, NIELS ULRIK

Patent Images

This patent contains figures and images illustrating the invention and its embodiment.

US10150670 Process generation synthesis 1
See all images <>

Abstract

A novel process for synthesis gas generation comprises treating a hydrocarbon feed in a primary reformer (PR), compressing at least part of the flue gas from the primary reformer in a compressor (C1), and feeding the compressed flue gas to a secondary reformer (SR) together with the primary reformer effluent. In the process, enriched air (EA) is added either to the primary reformer, to the secondary reformer or both. The process is especially suited for co-production of ammonia and methanol or for production of either ammonia or methanol. The total CO2 emission is lowered considerably by using the process of the invention.

Read more

Claims

1. A process for synthesis gas generation, said process comprising the following steps:

treating a hydrocarbon feed in a primary reformer (PR) to obtain a stream of flue gas and a stream of effluent, compressing at least part of the flue gas from the primary reformer in a compressor (C1), and feeding the compressed flue gas and the effluent to a secondary reformer (SR), wherein enriched air (EA) is added either to the primary reformer, the secondary reformer or both.

2. The process according to claim 1, further including the following steps:

passing the secondary reformer effluent through a shift conversion section, removing CO2 from the shift conversion effluent in a CO2 removal section, performing a synthesis gas clean-up of the CO2 removal section effluent, and compressing the resulting stream in a compressor (C3) and transferring the compressed stream to an ammonium loop (AL) for ammonia synthesis, wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis to urea.

3. The process according to claim 1, further including the following steps:

passing the secondary reformer effluent or part thereof through a shift conversion section, removing all the CO2 or part thereof from the shift converter effluent in a CO2 removal section, compressing the CO2 removal section effluent in a compressor (C2) and passing part or all of the compressed effluent through a methanol synthesis section (M), performing a synthesis gas clean-up of the methanol synthesis section effluent, compressing the resulting stream further in the compressor (C3), and transferring the resulting stream to an ammonium loop (AL) for ammonia synthesis, wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis or part thereof to urea.

4. The process according to claim 3, further including the following steps:

feeding the secondary reformer effluent directly to the compressor (C2), and passing the effluent from the compressor (C2) through a methanol synthesis section.

5. The process according to claim 1, wherein the enriched air is obtained by using an air separation unit (ASU).

6. The process according to claim 5, wherein the air separation unit (ASU) is based on membrane separation technology.

7. The process according to claim 1, wherein the hydrocarbon feed is a mixture of steam and optionally pre-reformed hydrocarbons, said hydrocarbons originating from any hydrocarbon source that can be used for reformer feeding.

Read more

Claim Tree

  • 1
    1. A process for synthesis gas generation, said process comprising
    • the following steps: treating a hydrocarbon feed in a primary reformer (PR) to obtain a stream of flue gas and a stream of effluent, compressing at least part of the flue gas from the primary reformer in a compressor (C1), and feeding the compressed flue gas and the effluent to a secondary reformer (SR), wherein enriched air (EA) is added either to the primary reformer, the secondary reformer or both.
    • 2. The process according to claim 1, further including
      • the following steps: passing the secondary reformer effluent through a shift conversion section, removing CO2 from the shift conversion effluent in a CO2 removal section, performing a synthesis gas clean-up of the CO2 removal section effluent, and compressing the resulting stream in a compressor (C3) and transferring the compressed stream to an ammonium loop (AL) for ammonia synthesis, wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis to urea.
    • 3. The process according to claim 1, further including
      • the following steps: passing the secondary reformer effluent or part thereof through a shift conversion section, removing all the CO2 or part thereof from the shift converter effluent in a CO2 removal section, compressing the CO2 removal section effluent in a compressor (C2) and passing part or all of the compressed effluent through a methanol synthesis section (M), performing a synthesis gas clean-up of the methanol synthesis section effluent, compressing the resulting stream further in the compressor (C3), and transferring the resulting stream to an ammonium loop (AL) for ammonia synthesis, wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis or part thereof to urea.
    • 5. The process according to claim 1, wherein
      • the enriched air is obtained by using an air separation unit (ASU).
    • 7. The process according to claim 1, wherein
      • the hydrocarbon feed is a mixture of steam and optionally pre-reformed hydrocarbons, said hydrocarbons originating from any hydrocarbon source that can be used for reformer feeding.
See all independent claims <>

Description

The present invention relates to a process for generation of synthesis gas by flue gas recycle. The process is especially suited for co-production of ammonia and methanol or for production of either ammonia or methanol.

More specifically, the invention is based on the fact that the consumption of hydrocarbon feed gas, such as natural gas (NG), in e.g. an ammonia plant and the emission of carbon dioxide from said plant can be significantly reduced by recycling the flue gas from the primary reformer to the secondary reformer as oxidant.

According to the invention, the carbon dioxide, which is also recycled with the flue gas, can be utilized for co-production of methanol, which also will reduce the carbon dioxide emission. Advantageously, enriched air can be used as combustion air for the primary reformer burners in order to improve the hydrogen/nitrogen ratio. However, enriched air can be added to the secondary reformer instead of being added to the primary reformer, or it can be added simultaneously to both reformers.

Co-production of ammonia and methanol is known as such from U.S. Pat. No. 8,692,034 belonging to the applicant. A CO2 pressure swing adsorption (CO2 PSA) off-gas stream is recycled to the primary reformer together with an off-gas fuel stream obtained from ammonia synthesis. The partly reformed gas from the primary reformer is further reformed in an air-blown secondary reforming stage, but no treatment of the flue gas from the primary reformer is mentioned. After the methanol synthesis step a methanation step is included. No emissions of the CO2 (captured from the methanol and ammonia synthesis) to the surroundings take place.

U.S. Pat. No. 8,303,923, also belonging to the applicant, describes a process for co-production of ammonia and methanol from a hydrocarbon feed. The off-gas fuel containing hydrogen, nitrogen and methane from the ammonia synthesis reactor is returned to the primary reforming stage, but there is no mention of any treatment of the flue gas from the primary reformer being transferred from the primary reformer to the secondary reformer. A methanation step is included after the methanol synthesis step for the conversion of carbon oxides, and water-gas shift (WGS) and CO2 removal steps are avoided.

A process concept called tri-reforming, which is basically a combination of steam reforming and CO2 reforming, where the CO2 originates from flue gas, is described by C. Song, W. Pan and S. T. Srimat in “Tri-reforming of Natural Gas using CO2 in Flue Gas of Power Plants without CO2-Preseparation for Production of Synthesis Gas with desired H2/CO Ratios”, Environmental Challenges and Greenhouse Gas Control for Fossil Fuel Utilization in the 21st Century, edited by Maroto-Valer et al., Kluwer Academic/Plenum Publishers, New York 2002, Chapter 18. This concept discloses novel ways of controlling emission of CO2. This includes utilizing CO2, present in flue gases together with O2, H2O and N2, without first having to separate it from the flue gas. By carrying out tri-reforming, the conversion of CO2 to methanol is enabled. Main differences between the tri-reforming approach and the present invention include the fact that, in tri-reforming, nitrogen in the flue gases is regarded as inert, ammonia is not mentioned as a product of a process including tri-reforming, and use of the commercially available Ni-based catalyst R67 is foreseen.

In connection with the tri-reforming approach, reservations may be expressed with respect to low pressure of synthesis gas (requiring compression of the synthesis gas stream), a high nitrogen content in the synthesis gas and a high volumetric flow in the reformer.

It has now turned out that the flue gas from e.g. ammonia and methanol co-production can be utilized, as nitrogen is required for the ammonia production and the CO2 can be used for increasing the carbon flow, thereby enabling methanol and urea production.

The co-production of ammonia and methanol or the production of either ammonia or methanol are two preferred embodiments of the process according to the invention. Other possible embodiments could, without being restricted thereto, be co-production of ammonia and hydrogen, co-production of methanol and carbon monoxide and co-production of ammonia, methanol and urea.

The appended FIGURE shows the reactor design for carrying out the process according to the present invention. A hydrocarbon feed consisting of a mixture of steam and optionally pre-reformed hydrocarbons, e.g. comprising natural gas (NG), is fed to a primary reformer (PR) together with a fuel and air. Enriched air (EA) is fed either to the primary reformer or to a secondary reformer (SR) or both. At least part of the flue gas from the primary reformer is compressed in a compressor (C1) and fed to a secondary reformer (SR) together with the primary reformer effluent, while the surplus flue gas, if any, is flared.

If for instance only ammonia is to be produced and/or it is desirable to be able to adjust the proportion between methanol and ammonia, then a shift conversion section and a bypass will optionally be necessary.

The effluent from the secondary reformer is fed, optionally via a shift conversion section, to a CO2 removal unit, where CO2 for urea production may be separated from the effluent. As mentioned, the CO2 removal unit may be bypassed. The effluent, whether having passed the CO2 removal unit or not, is compressed in a compressor (C2) and optionally subjected to methanol production in a methanol synthesis unit (M), from where raw methanol is withdrawn. The rest is sent via a compressor (C3) to an ammonia loop (AL).

Upstream of the ammonia loop a synthesis gas clean-up (s.c.) has to be made. As a minimum, CO and CO2 must be removed, e.g. by methanation. A nitrogen wash is also possible.

Thus, with reference to the appended FIGURE, the process according to the invention for generation of synthesis gas, preferably for co-production of ammonia and methanol or for production of either ammonia or methanol, by flue gas recycle comprises the following steps:

    • treating a hydrocarbon feed in a primary reformer,
    • compressing at least part of the flue gas from the primary reformer in a compressor, and
    • feeding the compressed flue gas to a secondary reformer together with the primary reformer effluent,

      wherein enriched air is added either to the primary reformer or to the secondary reformer or both.

The hydrocarbon feed is a mixture of steam and optionally pre-reformed hydrocarbons. These hydrocarbons may originate from any hydrocarbon sources that can be used for reformer feeding, such as natural gas.

The method of the invention can also be used for converting a larger amount of CO2 to urea. More specifically, the method of the invention may be used in connection with light natural gases for the production of urea. The CO2 content in the synthesis gas is too low for this purpose, and at present this CO2 deficit is compensated for by producing too much synthesis gas to obtain the necessary CO2 amount. The excess synthesis gas is used as fuel.

Depending on the desired end product(s), a number of further process steps may be added to the above sequence of steps. If for instance synthesis of ammonia and urea is desired, the following further process steps are included:

    • passing the secondary reformer effluent through a shift conversion section,
    • removing CO2 from the shift conversion effluent,
    • performing a synthesis gas clean-up of the CO2 removal section effluent, and
    • compressing the resulting stream in a compressor and transferring it to an ammonium loop for ammonia synthesis,

      wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis to urea.

For co-production of ammonia, urea and optionally also methanol, the following further process steps are included:

    • optionally passing the secondary reformer effluent or part thereof through a shift conversion section,
    • optionally removing all the CO2 or part thereof from the shift converter effluent,
    • compressing the CO2 removal section effluent in a compressor and optionally passing part or all of it through a methanol synthesis section,
    • performing a synthesis gas clean-up of the methanol synthesis section effluent,
    • optionally compressing the resulting stream further in the compressor, and
    • transferring the resulting stream to an ammonium loop for ammonia synthesis,

      wherein the amount of CO2 removed in the CO2 removal step is sufficient to convert all the ammonia produced in the ammonium synthesis or part thereof to urea.

If production of only methanol is desired, the following further process steps are included:

    • feeding the secondary reformer effluent directly to the compressor (C2), and
    • passing the effluent from the compressor C2 through a methanol synthesis section,

      wherein the module M in the synthesis gas is in the range from 2.0 to 3.0, preferably in the range from 2.0 to 2.5 and most preferably in the range from 2.0 to 2.2.

The enrichment of air can be done by using an air separation unit (ASU). An ASU separates atmospheric air into its primary components, i.e. nitrogen and oxygen and sometimes also argon and other rare inert gases. One of the most common methods for air separation is cryogenic distillation. Cryogenic ASUs are built to provide nitrogen or oxygen and often co-produce argon. Other methods, such as membrane separation, pressure swing adsorption (PSA) and vacuum pressure swing adsorption (VPSA), are commercially used to separate a single component from atmospheric air.

The invention is illustrated further by way of the following example.

EXAMPLE

The flue gas recycle method according to the invention was compared to two prior art methods without flue gas recycle, one with combined ammonia and methanol co-production and one with production of ammonia only.

In the following table 1, the process according to the invention is compared to both prior art combined ammonia and methanol production and prior art ammonia production only. In table 2, the process according to the invention is compared to a prior art urea production with a lean gas. In the latter case, the process according to the invention is used for ammonia production only.


TABLE 1
prior art NH3
prior art NH3
and CH3OH
production
process of
co-production
only
invention
Total HC
81255
76276
72738
(feed +
fuel), Nm3/h
Flue gas
0
0
11472
recirc.,
Nm3/h
EA,
0
0
38995
Nm3/h
NH3 prod.,
1492
2050
1910
MTPD
CH3OH prod.,
667
0
301
MTPD
Total CO2
57.4
50.8
22.5
emission,
MT/h


TABLE 2
process of the in-
prior art urea
vention, NH3 prod.
production
only
Total HC (feed +
76256
72738
fuel), Nm3/h
Flue gas recirc.,
0
11472
Nm3/h
EA, Nm3/h
0
38995
NH3 prod., MTPD
2050
1910
NH3 to storage,
99
0
MTPD
urea prod., MTPD
3443
3368
Total CO2
50.8
22.5
emission, MT/h

The CO2 emission is from the reformer stack only. Even if it is postulated that part of this can be used for urea production, the CO2 emission will still be around 45 MT/h for prior art production, i.e. twice as much as for production according to the invention.

Thus it appears from the comparisons in tables 1 and 2 that the total CO2 emission is lowered considerably by using the process of the invention.

Read more
PatSnap Solutions

Great research starts with great data.

Use the most comprehensive innovation intelligence platform to maximise ROI on research.

Learn More

Citation

Patents Cited in This Cited by
Title Current Assignee Application Date Publication Date
Production of hydrocarbons JOHNSON MATTHEY PUBLIC LIMITED COMPANY 23 October 2003 22 June 2006
Reforming device and reforming method, device for manufacturing chemical products comprising reforming device, and method for manufacturing chemical products MITSUBISHI HEAVY INDUSTRIES, LTD. 03 September 2013 20 March 2014
Preparation of ammonia synthesis gas M.W. KELLOGG COMPANY, THE, (A DE. CORP. FORMED IN 1987) 13 September 1982 30 October 1984
Reforming device and reforming method, and device for manufacturing chemical products equipped with reforming device and method for manufacturing chemical products MITSUBISHI HEAVY INDUSTRIES ENGINEERING LTD. 03 September 2013 23 July 2015
Systems and Methods for Producing Syngas and Products Therefrom KELLOGG BROWN & ROOT LLC 01 February 2011 02 August 2012
See full citation <>

More Patents & Intellectual Property

PatSnap Solutions

PatSnap solutions are used by R&D teams, legal and IP professionals, those in business intelligence and strategic planning roles and by research staff at academic institutions globally.

PatSnap Solutions
Search & Analyze
The widest range of IP search tools makes getting the right answers and asking the right questions easier than ever. One click analysis extracts meaningful information on competitors and technology trends from IP data.
Business Intelligence
Gain powerful insights into future technology changes, market shifts and competitor strategies.
Workflow
Manage IP-related processes across multiple teams and departments with integrated collaboration and workflow tools.
Contact Sales
Clsoe
US10150670 Process generation synthesis 1