The production process of n-butane maleic anhydride is divided into fixed bed process and fluidized bed process according to the reactor. There are two technical methods used in the subsequent treatment section, namely water absorption method and solvent absorption method.

1. 丁烷法固定床工艺：丁烷法固定床工艺主要由亨斯迈公司、BP、SD、 与苯氧化法基本相似，但正丁烷氧化转化率和选择性均比苯低，其顺酐的摩尔收率按正丁烷计仅为 50％~55％，而原料气体中苯和正丁烷的摩尔浓度基本相同。因此对于同样规模的生产装置，正丁烷法需要较大的反应器和压缩机。反应温度 400～450℃，压力为 125～130 MPa。为了降低正丁烷的单耗，比利时的 Pantochim公司采用尾气循环工艺，吸收塔顶出来的尾气约50％经处理后与新鲜空气一并进入反应器。该工艺可使正丁烷的单耗下降约 10％ 。

1. Butane fixed bed process: The butane fixed bed process is mainly composed of Huntsman, BP, SD, and is basically similar to the benzene oxidation method, but the conversion rate and selectivity of n-butane oxidation are lower than benzene. The molar yield of maleic anhydride is only 50%~55% based on n-butane, while the molar concentration of benzene and n-butane in the raw gas is basically the same. Therefore, for production units of the same scale, the n-butane method requires larger reactors and compressors. The reaction temperature is 400-450 ℃, and the pressure is 125-130 MPa. In order to reduce the unit consumption of n-butane, Pantochim Company in Belgium adopts a tail gas circulation process. About 50% of the tail gas from the top of the absorption tower is treated and enters the reactor together with fresh air. This process can reduce the unit consumption of n-butane by about 10%.

2.  丁烷法流化床工艺：流化床工艺是 Lummus 公司和 Lonza 公司合作开发的 ALMA 工艺。 流化床反应器中，正丁烷和空气分别进入反应器后混合，避免了其混合时发生爆炸的可能 因此原料气中正丁烷的摩尔分数可以提高到 4％，反应所需空气约为固定床的一半，减少了空气压缩机的投资和操作费用。流化床工艺的能耗低于固定床，但丁烷的单耗要比固定床高约 8％，另外流化床催化剂的磨损也较大。

2. Butane method fluidized bed process: The fluidized bed process is an ALMA process jointly developed by Lummus and Lonza companies. In a fluidized bed reactor, n-butane and air are mixed separately after entering the reactor, avoiding the possibility of explosion during mixing. Therefore, the molar fraction of n-butane in the feed gas can be increased to 4%, and the required air for the reaction is about half of that of a fixed bed, reducing the investment and operating costs of the air compressor. The energy consumption of the fluidized bed process is lower than that of the fixed bed, but the unit consumption of butane is about 8% higher than that of the fixed bed, and the wear of the fluidized bed catalyst is also significant.

3. 有机溶剂吸收法工艺：在采用丁烷法生产顺酐的初期，主要是一些苯法装置通过更换催化剂实现，就是新建的装置工艺也与苯法基本一致，均为水吸收法回收。由于丁烷氧化反应生成少量的乙酸和丙烯酸，而苯氧化反应几乎不生成乙酸和丙烯酸，另外丁烷氧化生成的水也比苯氧化多 1 倍，所以丁烷法水吸收工艺遇到的腐蚀和堵塞问题要比苯法多。

3. Organic solvent absorption process: In the early stages of using the butane method to produce maleic anhydride, some benzene process units were mainly achieved by replacing catalysts, and even the newly built unit process was basically the same as the benzene process, all of which were recovered by water absorption method. Due to the butane oxidation reaction generating a small amount of acetic acid and acrylic acid, while the benzene oxidation reaction hardly generates acetic acid and acrylic acid, and the amount of water generated by butane oxidation is also twice that of benzene oxidation, the butane method water absorption process encounters more corrosion and blockage problems than the benzene method.

为了减轻腐蚀 提高顺酐收率，降低能耗，各公司在改进丁烷氧化催化剂的同时 加强了对顺酐回收工艺的研究。溶剂吸收工艺采用低挥发性有机溶剂，顺酐收率比水吸收工艺约高 5％。ALMA 工艺采用六氢邻苯二甲酸二异丁酯（DIBE ，Huntsman 公司和 Conser 公司采用邻苯二甲酸二正丁酯（DBP）。 在工业生产中，这两种溶剂的消耗接近，DIBE 溶剂处理需进行水洗和碱洗两个过程， 而 DBP 溶剂仅需水洗。 另外， DIBE 的要高于 DBP。

In order to reduce corrosion, improve the yield of maleic anhydride, and reduce energy consumption, various companies have strengthened their research on the recovery process of maleic anhydride while improving butane oxidation catalysts. The solvent absorption process uses low volatile organic solvents, and the yield of maleic anhydride is about 5% higher than that of water absorption process. The ALMA process uses Diisobutyl Hexahydrophthalate (DIBE), while Huntsman and Consumer use Diisobutyl Phthalate (DBP). In industrial production, the consumption of these two solvents is similar. DIBE solvent treatment requires two processes: water washing and alkali washing, while DBP solvent only requires water washing. In addition, the price of DIBE is higher than that of DBP.