Modular mid-scale liquefied natural gas production system and method

Abstract

The present disclosure provides a system and method of efficiently designing a compact and modularized midscale liquefied natural gas production train. The train includes Natural Gas Pretreatment and Natural Gas Liquefaction sections designed in a unique way that reduces footprint, capital and operating cost, and overall project schedule. The train is configured into a framed compact multi-level structure with air coolers on the top level and process equipment underneath, which results in significant reduction in footprint compared to conventional stick-built design and significant reduction in footprint compared to conventional modularized design.

What is claimed is: 
     
         1 . A modularized liquefied natural gas production train, comprising:
 a framed multi-level structure comprising natural gas liquefaction process systems required for natural gas pretreatment, liquefaction, and refrigerant compression and related hardware including mechanical and electrical equipment, piping and instrumentation;   wherein air coolers are installed on a top level of the structure with other process equipment located on multiple levels underneath the air coolers;   wherein the structure has a central pipe rack the runs a longitudinal length of the structure with equipment located on both sides of the central pipe rack; and   wherein one or more refrigerant compressors and related power drivers are located at an end of the structure   
     
     
         2 . The modularized liquefied natural gas production train of  claim 1 , wherein the refrigerant compressors and related power drivers are longitudinally aligned with the longitudinal axis of the train. 
     
     
         3 . The modularized liquefied natural gas production train of  claim 1 , wherein the framed multi-level structure comprises one single module. 
     
     
         4 . The modularized liquefied natural gas production train of  claim 1 , wherein the framed multi-level structure comprises multiple modules along a longitude of the structure direction without impacting a layout of the structure and equipment. 
     
     
         5 . The modularized liquefied natural gas production train of  claim 1 , wherein the multiple modules comprise at least one of
 a process module and a refrigerant compressor module;   a pretreatment module, a liquefaction module, and a refrigerant compressor module; and   a pretreatment module and a liquefaction/refrigerant compressor module.   
     
     
         6 . The modularized liquefied natural gas production train of  claim 1 , wherein the air coolers are installed on a top level of the structure independent of an existence of one or more cantilever extensions extending laterally from the multi-level structure. 
     
     
         7 . The modularized liquefied natural gas production train of  claim 6 , wherein the air coolers that are installed on the top level occupy no more than the width of the top level. 
     
     
         8 . The modularized liquefied natural gas production train of  claim 6 , wherein tubing coupled with the air coolers comprise at least portions of high flux tubes. 
     
     
         9 . The modularized liquefied natural gas production train of  claim 1 , wherein the air coolers installed on a top level of the structure are installed so that air coolers that collectively form a majority heat load of the train and air flow are installed on one portion of the top level to reduce hot air recirculation and reduce a size of at least a portion of the air coolers. 
     
     
         10 . The modularized liquefied natural gas production train of  claim 1 , wherein an air cooler located in proximity to a gas turbine comprises a high air flow fan to reduce hot air recirculation to an intake of the gas turbine. 
     
     
         11 . The modularized liquefied natural gas production train of  claim 10 , further comprising vacant space created underneath the central pipe rack is configured to mitigate overpressure damage in the event of explosion and provide a safe distance between equipment and a maintenance space for equipment in a central location. 
     
     
         12 . The modularized liquefied natural gas production train of  claim 1 , wherein the one more refrigerant compressors and related power drivers located at an end of the structure are configured for interchangeable replacement between a gas turbine driver and an electric motor driver. 
     
     
         13 . The modularized liquefied natural gas production train of  claim 1 , wherein a liquefied natural gas liquefier is installed in a module and supported by structure of the module in proximity to a refrigerant compressor and configured to reduce hydrocarbon inventory in the train for safety. 
     
     
         14 . The modularized liquefied natural gas production train of  claim 13 , wherein the liquefier is located at one end of a liquefaction module and a liquefied natural gas rundown line is routed outside of the liquefaction module boundary from the same end and away from the liquefaction module to reduce presence of the liquefied natural gas rundown line within the module and inventory of liquefied natural gas within the module for enhanced safety. 
     
     
         15 . The modularized liquefied natural gas production train of  claim 13 , further comprising configuring locations of the liquefied natural gas liquefier and rundown line and associated piping to concentrate cryogenic lines and equipment with cryogenic service in an cryogenic area in proximity to an end of the module. 
     
     
         16 . The modularized and complete liquefied natural gas production train of  claim 13 , wherein at least a portion of the liquefied natural gas rundown line comprises vacuum insulated pipes to at least reduce requirements of liquefied natural gas troughs for spill containment. 
     
     
         17 . The modularized liquefied natural gas production train of  claim 1 , wherein a plurality of pumps are located on a bottom deck of the train along sides of the central corridor for maintenance access. 
     
     
         18 . The modularized liquefied natural gas production train of  claim 17 , wherein pumps in the liquefied natural gas liquefier and pre-treatment portions of the train are located in an area configured for collection of the potentially contaminated rainfall water underneath the pumps and reduction in capacity requirements of a water treatment system. 
     
     
         19 . The modularized liquefied natural gas production train of  claim 1 , wherein at least one large compressor and variable frequency drive is located at an edge of a module of the train for maintenance and safety. 
     
     
         20 . The modularized liquefied natural gas production train of  claim 1 , further comprising a lift system installed at an end of a module of the train and configured to move items between an elevation on the train and a lower elevation, wherein the central corridor space is configured to allow removal of equipment from within the module and transfer to the hydraulic lift system. 
     
     
         21 . The modularized liquefied natural gas production train of  claim 20 , wherein levels higher than a first level with the central corridor are configured with drop zone openings in the levels to the first level. 
     
     
         22 . The modularized liquefied natural gas production train of  claim 1 , wherein compression equipment is located on one side of the central corridor in a pre-treatment section and process towers are located on an opposite side of the pipe rack in the central corridor. 
     
     
         23 . The modularized liquefied natural gas production train of  claim 1 , wherein a pre-cooling heat exchanger is located on one side of the central corridor in a liquefaction section and a liquefier is located on an opposite side of the central corridor. 
     
     
         24 . The modularized and complete liquefied natural gas production train of  claim 1 , further comprising local electrical rooms and/or substations located at outside edges of the train and distal from liquefied natural gas rundown lines and a cryogenic area to have clean air intake access. 
     
     
         25 . The modularized and complete liquefied natural gas production train of  claim 1 , further comprising local instrument rooms and junction boxes located on an outside edge of a module of the train distal from liquefied natural gas rundown lines and a cryogenic area. 
     
     
         26 . The modularized complete liquefied natural gas production train of  claim 1 , further comprising oily water and amine drain systems pre-installed within at least one module frame beneath a basement floor distal from liquefied natural gas rundown lines and a cryogenic area.