Feasibility analysis of producing epichlorohydrin by gas-phase catalysis

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From the perspective of these four processes, most ECH production methods in China currently employ the reaction process of saponification to remove hydrogen chloride using alkaline solutions (Ca(OH)2 or NaOH). In the liquid-phase saponification dehydrochlorination process for dichloropropanol, not only is a large amount of alkali required, which increases the production cost of ECH, but it also leads to significant environmental pollution in the form of waste residues and wastewater, failing to meet the requirements for the environmental protection efforts of chemical enterprises. Brief description of the gas-phase catalytic process: Through continuous research and development, we have invented a method that utilizes dichloropropanol under gas-phase conditions, with the help of specific catalysts to facilitate the dehydrochlorination process, thereby directly producing epichlorohydrin and hydrogen chloride gas. Features of this process: it causes no pollution from waste gases, wastewater, or solid waste; the reaction temperature is low, resulting in relatively low energy consumption; the reaction conversion rate is >90%, which helps to **reduce the production costs of ECH. The process flow for the vapor-phase catalysis method is shown in the figure below. A comparison of several processes is presented in the table below:

| Raw material consumption | Reaction products | Glycerol method | Chloropropene method |
|------------------------|-------------------|-----------------|---------------------|
| 1/2 Ca(OH)2 | CH2CHOCH2Cl | 1/2 CaCl2 | Residual liquid |
| Conversion rate | Profit per ton | 12,974 | 92.5 |
| | | 0.97 | 6.117 |
| | | 1.55 | 1.16 |
| | | 1.00 | 1.43 |
| Cost calculation | | 9,917.12 | 693.33 |
| | | 10,500.00 | 200.00 |
| Market price | | 6,400.00 | 600.00 |
| | | 10,500.00 | |

For the vapor-phase catalysis method:
| Raw material consumption | Reaction products | Catalyst | CH2CHOCH2Cl | HCl | Residual liquid | Conversion rate | Profit per ton |
|------------------------|-------------------|----------|-------------|----|----------------|----------------|---------------|
| | | | | | | | |
| Conversion rate | | | | | | | |
| | | | | | | | |
| Cost calculation | | | | | | | |
| Market price | | | | | | | |

Comparison between vapor-phase catalysis and liquid-phase saponification:
1. The reaction conversion rate for the liquid-phase saponification process is approximately 85–90%.
2. The reaction conversion rate for the vapor-phase catalysis process is >90%, meaning the product conversion rate is 5–10% higher than that of the liquid-phase saponification process. 　3: The gas-phase catalytic dehydrochlorination of dichloropropanol to produce epichlorohydrin results in costs that are about 400–500 yuan per ton lower compared to the cost of producing epichlorohydrin through liquid-phase saponification. 4: The gas-phase catalytic production process does not generate any environmental pollution in the form of waste substances. By comparing the data on various aspects of these two processes, we can draw the following conclusions: 1. The gas-phase catalytic process does not generate any waste pollution, which is in line with the principles of green, energy-saving, and environmentally friendly production. 2. The profit generated per ton of epichlorohydrin produced using the gas-phase catalytic process is about 400–500 yuan per ton higher than that obtained using the current saponification method. 3: The process route is short, equipment investment is minimal, and fewer funds are required; it also allows for the extensive use of some of the equipment used in the saponification process. 4: The cost recovery period is short; the investment cost can generally be recovered within 3 to 5 months.