Modularized System and Method for Urea Production Using Stranded Natural Gas

Abstract

A modular system and method for producing urea from stranded natural gas includes removal of foreign particulate matter to obtain a substantially homogeneous gas. The gas is processed by controlling the quality of the stranded natural gas to maintain a substantially homogenous mixture The resultant gas stream is further cleaned and compressed to a high pressure of about 3,000 psi. The resultant ammonia stream is processed in a bypass recycling loop system at 30% conversion rate at a high pressure of about 6,000 to 7,000 psi. The equipment associated with each of the process steps may be skid mounted for portability and/or contained within the footprint of a standard 48-foot flatbed trailer.

What is claimed is: 
     
         1 . A method for producing a fertilizer or a fuel from a stranded natural gas feedstock, the method comprising the steps of:
 i. capturing a natural gas feedstock that includes at least one stranded natural gas feedstock from at least one stranded natural gas source;   ii. removing moisture from the captured natural gas feedstock;   iii. removing potential disruptive inorganics and organics from the substantially moisture-free natural gas feedstock;   iv. reformulating the substantially clean natural gas feedstock;   v. recovering a CO 2  stream from the reformulated natural gas feedstock; and   vi. combining the recovered CO 2  stream with a NH 3  stream to form at least one of a fertilizer and a fuel.   
     
     
         2 . A method according to  claim 1  further comprising the step of blending the captured natural gas feedstock prior to the reformulating step to form a substantially homogenous blend. 
     
     
         3 . A method according to  claim 2  wherein the captured natural gas feedstock includes at least two stranded natural gas feedstocks each having at least one different processing characteristic. 
     
     
         4 . A method according to  claim 2  further comprising the blending step resulting in a consistent BTU value for the homogeneous blend. 
     
     
         5 . A method according to  claim 2  further comprising the blending step resulting in a consistent sulfur content for the homogeneous blend 
     
     
         6 . A method according to  claim 1  wherein the moisture removal step removes moisture to a predetermined moisture content. 
     
     
         7 . A method according to  claim 1  further comprising a portion of the reformulating step occurring in a temperature range of about 500° to 800° C. 
     
     
         8 . A method according to  claim 1  further comprising the reformulating step including the sub-step of compressing the resultant CO 2  stream to a pressure of at least about 3,000 psi. 
     
     
         9 . A method according to  claim 1  further comprising the step of processing the NH 3  stream in a bypass recycling loop. 
     
     
         10 . A method according to  claim 9  wherein the bypass recycling loop operates at a high pressure range of between about 6,000 to 7,000 psi and results in about a 30% conversion rate. 
     
     
         11 . A method according to  claim 1  wherein equipment embodying the method is placed in series with at least one other set of equipment embodying the method. 
     
     
         12 . A method according to  claim 1  wherein equipment embodying the method is placed in parallel with at least one other set of equipment embodying the method. 
     
     
         13 . A method according to  claim 1  wherein all equipment associated with at least one of the steps (i) to (vi) is substantially immediately portable between a first and second stranded natural gas source site. 
     
     
         14 . A method according to  claim 13  wherein all equipment associated with at least one of steps (i) to (vi) is temporarily mounted within a footprint of a standard flatbed truck trailer. 
     
     
         15 . A method according to  claim 13  wherein all equipment associated with at least one of the steps (i) to (vi) is skid mounted. 
     
     
         16 . A method according to  claim 1  wherein all equipment associated with at least one of the steps (i) to (vi) is temporarily positioned at a location in fluid communication with the at least one stranded natural gas source. 
     
     
         17 . For producing a fertilizer or a fuel, a system comprising:
 a purification module;   a reformulation module;   a shift conversion module;   an ammonia module; and   a urea conversion;   at least one of the modules being substantially immediately portable between a first and second stranded natural gas source site;   a natural gas feedstock including at least one stranded natural gas feedstock being inputted to the purification module.   
     
     
         18 . A system according to  claim 17  wherein the purification module provides a substantially homogenous blend of two or more stranded natural gas feedstocks to the reformulation module. 
     
     
         19 . A system according to  claim 17  wherein a resultant gas stream from the reformulation module is compressed to a pressure of at least about 3,000 psi. 
     
     
         20 . A system according to  claim 17  wherein the ammonia module further comprises a bypass recycling loop operating in a high pressure range of between about 6,000 to 7,000 psi and resulting in about a 30% conversion rate.