Ammonia plant upgrading-multistage integrated chilling of process air compressor with ammonia compressor followed by air flow split and multistage air preheating to secondary ammonia reformer

• US 9,772,129 B2
• Filed: 08/14/2013
• Issued: 09/26/2017
• Est. Priority Date: 08/17/2012
• Status: Active Grant

• Current Assignee: Vinod Kumar Arora
• Original Assignee: Vinod Kumar Arora
• Inventors: Arora, Vinod Kumar
• Primary Examiner(s): Tran, Len
• Assistant Examiner(s): Vazquez, Ana
• Application Number:
  US14/241,018
• Publication Number:
  US 20140223951A1
• Time in Patent Office: 1,504 Days
• Field of Search: 62335, 165 63
• CPC Class Codes: B01J 2219/00006 Large-scale industrial plants
• CPC Class Codes: C01C 1/003 Storage or handling of ammonia
• CPC Class Codes: C01C 1/0405 from N2 and H2 in presence of a catalyst
• CPC Class Codes: F25B 29/003 of the compression type system
• CPC Class Codes: F25B 7/00 Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit F25B9/00 takes precedence
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• CPC Class Codes: Y02P 20/50 Improvements relating to the production of bulk chemicals
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

An ammonia plant system upgrade utilizing both a direct and indirect multistage chilling system in the ammonia plant air compression train to increase process air flow to the secondary ammonia reformer of an existing ammonia plant as well as upgrades to provide more pre-heating along with increased process air flow.

Claims

1. An upgrade to an existing ammonia plant utilizing a new direct multistage chilling system in an existing ammonia plant air compression train of the existing ammonia plant to increase process air flow to an existing secondary reformer of the existing ammonia plant comprising:

a. a new two stage suction air chiller in the existing ammonia plant air compression train that chills incoming process air by heat exchange with expanded high pressure ammonia from an existing ammonia compression system of the existing ammonia plant;

b. additional new two stage air chillers between each of the existing air compressors of the existing ammonia plant air compression train, each new air chiller chilling incoming air by heat exchange with expanded high pressure ammonia from the existing ammonia compression system of the existing ammonia plant.

2. The upgrade to an existing ammonia plant utilizing a new direct multistage chilling system in the existing ammonia plant air compression train of the existing ammonia plant to increase process air flow to the existing secondary ammonia reformer of the ammonia plant of claim 1 further comprising:

a. an added new steam preheater for preheating an increased process air flow;

b. wherein the preheated and increased production flow from the air compression train is separated into three streams which are further heated in;

i. the existing dedicated process air preheat convection coils of the in the existing ammonia plant;

ii. available excess heat transfer surface of the existing feed preheat convection coils in the existing ammonia plant modified to accommodate a portion of the preheated process air flow from the existing air compression train of the existing ammonia plant; and

iii. available excess heat transfer surface of existing boiler feedwater convection coils of the existing ammonia plant modified to accommodate a portion of the preheated process air flow from the existing air compression train of the existing ammonia plant;

c. wherein the combined heated three streams are fed to the existing secondary reformer of the existing ammonia plant.

3. A method for upgrading An existing ammonia plant utilizing a new direct multistage chilling system in an existing ammonia plant air compression train to increase process air flow to an existing secondary reformer of the existing ammonia plant comprising the steps of:

a. providing a new two stage suction air chiller in the existing ammonia plant air compression train for chilling incoming air by heat exchange with expanded high pressure ammonia from an existing ammonia compression system of the existing ammonia plant;

b. providing additional new air chillers between each stage of the existing air compressors of the existing air compression train of the existing ammonia plant for chilling the compressed incoming air to each of the stages of an existing air compressor by heat exchange with expanded high pressure ammonia from the existing ammonia compression system of the existing ammonia plant.

4. The method for upgrading an existing ammonia plant utilizing a direct multistage chilling system in the existing ammonia plant air compression train to increase process air flow to the existing secondary reformer of the existing ammonia plant of claim 3 further comprising the steps of:

a. providing an added new steam preheater for heating an increased process air flow;

b. splitting the preheated and increased process air flow from the air compression train into three streams;

c. wherein each of the three streams are further heated in;

i. the available existing dedicated process air preheat convection coils in the existing ammonia plant;

ii. available excess heat transfer surface of existing feed preheat convection coils in the existing ammonia plant modified to accept a portion of the preheated and increased process air flow from the air compression train of the existing ammonia plant;

iii. modified available excess heat transfer surface of existing boiler feedwater convection coils modified to accept a portion of the preheated and increased process air flow from the air compression train of the existing ammonia plant;

d. wherein the combined heated three streams are fed to the secondary reformer.