低溫儲(chǔ)罐是用于存放液態(tài)氧、氮、氬、二氧化碳等介質(zhì)的立式或臥式雙層真空 熱儲(chǔ)槽。內(nèi)膽選用材料為奧氏體不銹鋼；外容器材料根據(jù)用戶地區(qū)不同，按 規(guī)定選用為Q235-B、Q245R或345R，內(nèi)、外容器夾層充填 熱材料珠光砂或鋁箔、保溫棉并抽真空。 基礎(chǔ)形式： 低溫儲(chǔ)罐本身的設(shè)計(jì)定義并無(wú)統(tǒng)一的標(biāo)準(zhǔn)。根據(jù)不同的工藝要求和介質(zhì)儲(chǔ)存方式，將低溫罐定義為單容器罐、雙容器罐和全容器罐等三種罐體形式。單容器罐一般是有一個(gè)鋼制內(nèi)罐加上保溫外殼組成，而雙容器罐和全容器罐則是由一個(gè)鋼制內(nèi)罐和一個(gè)鋼制或采用混凝土(一般為預(yù)應(yīng)力混凝土)制成的外罐組成，保溫設(shè)在內(nèi)外罐壁之間，目前較多采用的是雙容罐形式。 在進(jìn)行低溫罐設(shè)計(jì)時(shí)，由于罐內(nèi)低溫介質(zhì)的傳導(dǎo)作用，使得地基土較易產(chǎn)生凍漲并使土體隆起，進(jìn)而造成基礎(chǔ)破壞，因此為消除這一不利因素，除了在罐底板與基礎(chǔ)底板表面之間設(shè)置保溫措施外，還需對(duì)罐基礎(chǔ)采取防凍措施，通常的做法有兩種，一是在基礎(chǔ)底板內(nèi)采用電或其他加熱系統(tǒng)，即做成帶有循環(huán)加熱系統(tǒng)的筏板式基礎(chǔ)，另一種是采用將基礎(chǔ)底板架空，通過(guò)架空形成的空氣層將基礎(chǔ)底板與地基土分隔開(kāi)。前者因加熱系統(tǒng)成本較高，一般不常采用。在國(guó)內(nèi)引進(jìn)建造的大多數(shù)低溫罐中，普遍采用了架空筏板式基礎(chǔ)形式。架空層的凈高，一般除根據(jù)工藝管道和設(shè)備布置要求確定外，尚需根據(jù)罐內(nèi)儲(chǔ)存介質(zhì)溫度的高低進(jìn)行一定的溫度傳導(dǎo)計(jì)算后來(lái)確定。架空筏板式基礎(chǔ)又可分為單筏板(承臺(tái))和雙筏板(承臺(tái))架空兩種形式，在地質(zhì)條件較好的情況下，一般可采用雙筏板基礎(chǔ)形式；但由于低溫儲(chǔ)罐對(duì)基礎(chǔ)沉降的要求相對(duì)較高，在大多數(shù)情況下，特別時(shí)地質(zhì)條件較差的軟土地基上，則多采用單筏板(承臺(tái))樁基，有時(shí)也有采用雙筏板(承臺(tái))樁基。
Low temperature storage tank is used to store liquid oxygen, nitrogen, argon, carbon dioxide and other media of vertical or horizontal double-layer vacuum thermal storage tank. The inner container is made of austenitic stainless steel; the outer container is made of Q235-B, Q245R or 345r according to the regulations according to the user's region. The inner and outer containers are filled with pearlite or aluminum foil, insulation cotton and vacuumized. Foundation form: there is no uniform standard for the design definition of cryogenic storage tank itself. According to the different process requirements and medium storage methods, the cryogenic tank is defined as three tank forms: single vessel tank, double vessel tank and full container tank. The single container tank is generally composed of a steel inner tank and an insulation shell, while the double container tank and the whole container tank are composed of a steel inner tank and an outer tank made of steel or concrete (generally prestressed concrete). The thermal insulation is set between the inner and outer tank walls. At present, the double tank is widely used. In the design of low-temperature tank, because of the conduction of low-temperature medium in the tank, the foundation soil is easy to freeze up and make the soil heave, thus causing foundation damage. Therefore, in order to eliminate this unfavorable factor, in addition to setting thermal insulation measures between the tank bottom plate and the foundation bottom plate surface, it is also necessary to take anti freezing measures for the tank foundation Electric or other heating system is adopted, that is, raft foundation with circulating heating system is made. The other is to use the foundation slab overhead, and the foundation slab is separated from the foundation soil by the air layer formed by overhead. The former is not often used because of the high cost of heating system. In most of the low-temperature tanks imported and constructed in China, the overhead raft foundation is widely used. Generally, the net height of overhead layer shall be determined according to the requirements of process pipeline and equipment layout, and certain temperature conduction calculation shall be conducted according to the temperature of storage medium in the tank. The elevated raft foundation can be divided into single raft (bearing platform) and double raft (bearing platform) overhead two forms. In the case of good geological conditions, the double raft foundation can be generally adopted; however, due to the low temperature storage tank's requirements for foundation settlement are the same for high, in most cases, especially on the soft soil foundation with poor geological conditions, single raft (pile cap) pile foundation is often used, and sometimes double raft (pile cap) pile foundation is also used.
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