【正文】 process selection has often been highly influenced by the specific power consumption, ., refrigerant pression power divided by the train capacity. This is certainly an important parameter, since refrigerant pressors are the largest single cost and energy consumption ponents in an LNG train. Conventional wisdom would be that lower specific power consumption would result in lower refrigerant pression costs and additional LNG production from a fixed feed gas rate. In actuality it is a more plicated picture. Figure 1 plots the specific power consumptions for a variety of liquefaction processes against the number of cycles employed based on consistent conditions. 4 SMR Single Mixed Refrigerant C3MR Propane precooled Mixed Refrigerant C3MRN2 Propane precooled Mixed Refrigerant plus Nitrogen expander cycle Cascade Pure propane, ethylene, and methane DMRSWHE Dual Mixed Refrigerant with single pressure levels and SWHEs DMRBAHX Dual Mixed Refrigerant with multiple pressure levels and BAHXs TMR Triple Mixed Refrigerant Figure 1 Process Specific Power Comparison In general, mixed refrigerant processes are more efficient than pure po nent processes and additional cycles improve efficiency. However, both of these efficiency improvements e at the expense of increased process plexity. Another factor that plicates the picture above is that it only considers a process parison and not a refrigerant pressor or driver parison. Differences in pressor efficiency, the need for a speedincreasing gear, or driver efficiency can overwhelm some of the differences shown. Considerations for the generation and distribution of electric power for motor driven LNG processes can further plicate the parison. The LNG industry is changing in a number of areas that can also impact the selection of the best liquefaction process. While stickbuilt LNG plants are still the norm, modularization of LNG facilities are more attractive for offshore applications or where labor costs are very high and/or productivity is low. Modular construction is routinely applied for offshore oil processing. However, oil processing is much simpler than LNG production and process selection is generally not an important consideration. All these factors point to the need for more pact, lighter mechanical designs. Another important future consideration is the increasing need to reduce greenhouse gas emissions. Aeroderivative gas turbine drivers are an obvious choice for higher thermal efficiency or modular application but are not available in sizes as large as industrial gas turbines. Consequently, a process suitable for large 95 MW industrial gas turbines may not be well suited for a 35 MW aeroderivative gas turbine. Combinedcycle power generation is another option for achieving increased thermal efficiency and can be adapted to any of these processes, but is not well suited for modular construction or for offshore application due to the additional weight of motors, generators and distribution equipment as well as limited aeroderivative gas turbine choices for very large (100MW) power generators. The value of thermal efficiency can also bee a more important process selection criterion when the feed gas to the LNG plant is relatively expensive or supply is limited. An efficient process can allow for a reduced cost development plan through a lower gas rate, or extend the gas production plateau from the reservoir to make a more profitable project. 5 IMPACT OF EQUIPMENT COSTS Our process research paring liquefaction processes has demonstrated that the primary difference in the costs for the different liquefaction processes is the choice of equipment utilized. Process licensors tailor their process to make it capital and thermally efficient given the owners39。這一工藝也能靈活地適應(yīng)大范圍的供給、價(jià)格和產(chǎn)品銷(xiāo)售要求。如果有一種可能性，即一些能源可以應(yīng)用到火車(chē)上，那么另一個(gè)可取的特點(diǎn)就是使用制冷劑作為一種實(shí)用工具，來(lái)允許其作用的擴(kuò)展。 液化天然氣行業(yè)正在改變，在一些領(lǐng)域，也可以影響最好的液化過(guò)程。 設(shè)備成本的影響 我們 所做的 比較液化工藝的研究已經(jīng)證明：在不同的液化工藝的成本差異中最主要的不同 處 是對(duì)利用設(shè)備的選擇。最后，一個(gè)全電氣化的驅(qū)動(dòng)配置被認(rèn)為 是較高的成本和提高工廠的可用性之間的一個(gè)折中的選擇。 15 高效擴(kuò)增 LNG 廠使擴(kuò)張的 火車(chē) 長(zhǎng)期受益，通常從同樣大的資源中得到提供 ， 雖然可用于多級(jí)列車(chē)發(fā)展的已發(fā)現(xiàn)的大油田的數(shù)量正在減少，但附近的小資源對(duì)經(jīng)濟(jì)的擴(kuò)張仍是有