【正文】 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。雖然這些大型的列車適合于卡塔爾大型的燃?xì)赓Y源，但是未來更節(jié)能的發(fā) 展要求使不同的處理工藝方法成為必要性。這一工藝也能靈活地適應(yīng)大范圍的供給、價格和產(chǎn)品銷售要求。關(guān)于大型液化天然氣火車的討論中常常被人們忽略的是：維持這樣的火車工作超過 25 年需要約 370 GCM 的資源，這幾乎和 425 GCM 的印度阿倫場一樣大，這個產(chǎn)量是這個地區(qū)液化天然氣廠的極限。如果有一種可能性，即一些能源可以應(yīng)用到火車上，那么另一個可取的特點就是使用制冷劑作為一種實用工具，來允許其作用的擴(kuò)展。 在一般情況下，混合制冷劑工藝比單一制冷劑工藝更有效，并且額外的周期能提高工作效率，然而，工藝過程的復(fù)雜性都提高了工作效率。 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程。 未來另一個重要的考慮因素是對減少溫室氣體排放量不斷增長的要求，對于更高的熱效率或模塊化的應(yīng)用模式，航改燃?xì)廨啓C(jī)驅(qū)動是顯而易見的選擇，因此，適合 95 兆瓦的大型工業(yè)燃?xì)鉁u輪機(jī)的過程未必適合 35 兆瓦的航改燃?xì)廨啓C(jī)。 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 是對利用設(shè)備的選擇。 沒有 單一制冷劑的固定 沸點溫度 的特點 ， 一個多元混合制冷的過程 能夠 靈活 地 允許這樣的轉(zhuǎn) 變 。最后，一個全電氣化的驅(qū)動配置被認(rèn)為 是較高的成本和提高工廠的可用性之間的一個折中的選擇。 14 這將會利用釬焊鋁熱交換器來提供： ? 多個廠家的成本和進(jìn)度的利益 ? 經(jīng)濟(jì)規(guī)模較大的吞吐量 ? 易于模塊化 釬焊鋁熱交換器在每個壓力水平下影響制冷劑的分離，從操作和設(shè)計相關(guān)的問題中得到保護(hù)，只有液體輸送到釬焊鋁熱交換器的核心部位，而繞過蒸汽回到壓縮系統(tǒng)中。 15 高效擴(kuò)增 LNG 廠使擴(kuò)張的 火車 長期受益，通常從同樣大的資源中得到提供 ， 雖然可用于多級列車發(fā)展的已發(fā)現(xiàn)的大油田的數(shù)量正在減少，但附近的小資源對經(jīng)濟(jì)的擴(kuò)張仍是有潛力的。作為通用的制冷劑可以用于任何液化過程，但最適合雙混合制冷劑，制冷劑的回饋壓力可以更高，從而導(dǎo)致較小的管道分布橫跨制冷劑液化天然氣廠，圖 4 顯示了一個這樣的