# US 2017/0283371 A1 · Process for production of ammonia and derivatives, in particular urea > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0283371 A1 - Document ID: US20170283371A1 - Status: Published application - Kind: A1 - Application number: 15/508,758 - Filed: 2015-08-05 - Published: 2017-10-05 - Earliest claimed: 2014-09-05 - Assignees: Casale SA - Applicants: Casale SA - Inventors: Geoffrey Frederick Skinner; Raffaele OSTUNI - Web page: https://patentgrep.com/patent/US20170283371A1 ## CPC - C07C 273/10: combined with the synthesis of ammonia - B01J 7/00: Apparatus for generating gases (production of inert gas mixtures B01J19/14; for generating specific gases, see the relevant subclasses, e.g. C01B, C10J {; in "air bags" on vehicles B60R21/26; for starter gas F02C7/26; blasting cartridges for producing gas under pressure F42B3/04}) - C01B 3/025: Preparation or purification of gas mixtures for ammonia synthesis - C01C 1/0405: {from N2 and H2 in presence of a catalyst} - C01C 1/0452: {Heat exchangers} - C01C 1/0488: {Processes integrated with preparations of other compounds, e.g. methanol, urea or with processes for power generation} - F01N 5/02: the devices using heat - C01B 2203/0233: the reforming step being a steam reforming step - C01B 2203/0244: the reforming step being an autothermal reforming step, e.g. secondary reforming processes - C01B 2203/0255: containing a non-catalytic partial oxidation step - C01B 2203/0283: containing a CO-shift step, i.e. a water gas shift step - C01B 2203/0288: containing two CO-shift steps - C01B 2203/0415: Purification by absorption in liquids - C01B 2203/0475: the impurity being carbon dioxide - C01B 2203/068: Ammonia synthesis - C01B 2203/0894: Generation of steam - C01B 2203/142: At least two reforming, decomposition or partial oxidation steps in series - C01B 2203/84: Energy production - Y02P 20/10: Process efficiency - Y02P 20/129: Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines - Y02P 20/52: using catalysts, e.g. selective catalysts - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C01C: AMMONIA; CYANOGEN; COMPOUNDS THEREOF ({metal hydrides, monoborane, diborane or addition complexes thereof C01B6/00}; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; azides C01B21/08; {compounds other than ammonia or cyanogen, containing nitrogen, non-metals and optionally metals C01B21/082}; metal imides or amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; compounds containing silicon C01B33/00; compounds containing boron C01B35/00) - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A process for producing ammonia and a derivative of ammonia from a natural gas feed comprising conversion of natural gas into a make-up synthesis gas; synthesis of ammonia; use of said ammonia to produce said derivative of ammonia, wherein a portion of the natural gas feed is used to fuel a gas engine; power produced by said gas engine; is transferred to at least one power user of the process, such as a compressor; heat is re-covered from exhaust gas of said gas engine;, and at least part of said heat may be recovered as low-grade heat available at a temperature not greater than 200° C., to provide process heating to at least one thermal user of the process, such as CO2 removal unit or absorption chiller; a corresponding plant and method of modernization are also disclosed. ## Claims ### Claim 1 A process for producing ammonia and a derivative of ammonia from a natural gas feed (NG) comprising: conversion of natural gas into synthesis gas in a front-end section; synthesis of ammonia from said synthesis gas in a synthesis loop; use of at least part of said ammonia to produce said derivative of ammonia, said process being carried out with power users requiring a mechanical power for operation, and thermal users requiring a heat input for operation; wherein: a portion of said natural gas feed is used to fuel a reciprocating gas engine; power produced by said gas engine is used to cover at least partially the power demand of said power users; heat is recovered from exhaust gas of said gas engine, and at least part of said heat is recovered, to provide heating to at least one of said thermal users, wherein heat recovery from said exhaust of said gas engine is at least in part low grade heat transferred to at least one of said thermal users via a heat exchange medium, said medium being heated by indirect heat exchange with the exhaust gas to a temperature which is not greater than 200° C. ### Claim 2 (depends on 1) The process according to claim 1, said power being transferred from said gas engine to at least one of said power users in an electrical or mechanical form. ### Claim 3 (depends on 1) The process according to claim 1, wherein said conversion of natural gas into synthesis gas in said front-end section is carried out by steam reforming with a global steam-to-carbon molar ratio not greater than 2.7. ### Claim 4 (depends on 1) The process according to claim 1, wherein said heat recovered from said gas engine is used to provide heat to one or more of the following thermal users, by means of at least one of the following: heating of a heat transfer medium such hot water or hot oil, the regeneration of a CO2-rich solution in a CO2 removal unit, the powering of an absorption refrigeration chiller, the distillation of an ammonia-rich aqueous ammonia solution, heating of natural gas or other fuel, heating of process air, heating of combustion air, direct use of gas engine exhaust as a combustion medium. ### Claim 5 (depends on 1) The process according to any of the previous claim 1, wherein: a first portion of heat recovered from exhaust of said gas engine is used in a heat recovery steam generator to produce steam and said steam is expanded in a backpressure or extraction steam turbine producing further mechanical power, thus forming a combined cycle, and a second portion of heat recovered from exhaust of said gas engine is used to provide said low-grade heat. ### Claim 6 (depends on 5) The process according to claim 5, wherein a steam flow taken from said backpressure or extraction steam turbine is used to provide heating to at least one of said thermal users. ### Claim 7 (depends on 1) The process according to claim 1, wherein said conversion of natural gas into synthesis gas comprises a primary steam reformer and a secondary reformer, or a pure autothermal reformer, or a partial oxidation reactor, obtaining a raw synthesis gas, and a purification of said raw synthesis gas, comprising at least a shift reaction and removal of carbon dioxide from the shifted gas. ### Claim 8 (depends on 7) The process according to claim 7, said shift conversion being a high temperature shift (FITS) on iron-based catalyst, or a medium temperature shift (MTS) on copper-based catalyst. ### Claim 9 (depends on 7) The process according to claim 7, said removal of carbon dioxide being carried out with any of the following methods: amines, or activated amines, or potassium carbonates. ### Claim 10 (depends on 1) The process according to claim 1, said derivative of ammonia being urea. ### Claim 11 (depends on 1) The process according to claim 1, in which said power users are at least one of a compressor, a fan or a pump. ### Claim 12 (depends on 1) The process according to claim 1, wherein said exhaust gas from said gas engine is used to supply in part the combustion medium for a fired reformer or other fired heater. ### Claim 13 (depends on 1) The process according to claim 1, wherein part of the fuel for the gas engine is a waste fuel stream such as: a purge gas taken from said ammonia synthesis loop, or a tail gas from a loop purge recovery unit. ### Claim 14 A plant for producing ammonia and a derivative of ammonia, particularly urea, from a natural gas feed (NG), said plant comprising: a front-end section for generation of ammonia make-up synthesis gas; a synthesis loop for synthesis of ammonia from said make-up synthesis gas; a section for the conversion of at least part of the synthesized ammonia into said derivative; power users requiring a mechanical power for operation, and at least one thermal user requiring a heat input for operation; wherein said plant further comprises: at least one reciprocating gas engine, the power produced by said gas engine being transferred to at least one of said power users, heat recovery means for recovering heat from exhaust of said gas engine, and in that said plant further comprises: heat recovery means for recovery of low-grade heat from exhaust of said gas engine via a heat exchange medium, said heat recovery means comprising indirect heat exchange means arranged to heat said medium to a temperature not greater than 200° C., and said plant comprises means arranged to transfer said low-grade heat to at least one of said thermal users. ### Claim 15 A method of modernizing a plant for producing ammonia and a derivative of ammonia, particularly urea, wherein: said plant comprises a front-end section for generation of ammonia make-up synthesis gas; a synthesis loop for synthesis of ammonia from said make-up synthesis gas; a section for the conversion of at least part of the synthesized ammonia into said derivative; the plant also comprising power users and thermal users; wherein: the provision of at least one reciprocating gas engine, and the provision of suitable power transfer means to transfer the power produced by said engine to at least one of said power users, the provision of heat recovery means for recovering a heat from exhaust gas of said gas engine, and the provision of heat recovery means for recovering a low-grade heat from exhaust gas of said gas engine, by indirect heat exchange with a medium, said medium being heated by the exhaust gas to a temperature not greater than 200° C., the provision of the so recovered low-grade heat to at least one of said thermal users of the plant, or to at least one newly-installed thermal user. ### Claim 16 (depends on 15) The method according to claim 15, wherein the provision of said power transfer means includes: the provision of an electrical motor and the provision of an electrical generator coupled to said gas engine. ### Claim 17 (depends on 16) The method according to claim 16, said newly-installed thermal user being one of the following: a reboiler of a CO2-rich solution in a CO2 removal unit, a reboiler of an absorption refrigeration chiller, a reboiler of an ammonia-rich aqueous ammonia solution distillation system, a preheater of a natural gas or fuel gas, a preheater of process air, a preheater of combustion air. ### Claim 18 (depends on 15) The method according to claim 15, further comprising the step of reducing the global steam-to-carbon ratio of the front-end section to a value lower than the original. ### Claim 19 (depends on 1) The process according to claim 1, wherein said conversion of natural gas into synthesis gas in said front-end section is carried out by steam reforming with a global steam-to-carbon molar ratio in the range 2.3 to 2.6. ### Claim 20 (depends on 18) The method according to claim 18, wherein said global steam-to-carbon ratio of the front-end section is in a range of 2.3 to 2.6.