What is steam explosion?

The physical concept of steam explosion is: energy is released abruptly in a short period of time. For example, firecrackers can be shattered with a small amount of **, accompanied by a clear and loud cracking sound. On the other hand, although fireworks contain more explosives than firecrackers, due to the way **energy is released – in a gradual manner over time – they cannot shatter their own structure; this is because their energy density is insufficient, or in other words, they produce less work per unit of time.

It is characterized by the formation of a steam explosion gas storage chamber inside it; an arc-shaped front chamber surface is present on the front side of the steam explosion machine, a conical rear chamber surface on the back side, and a nozzle with a reduced diameter at the far end. A one-way valve is pivotally mounted on the nozzle. One or more oil mist injection holes and water mist injection holes are provided on the front chamber surface of the steam explosion machine, to which fuel atomization devices and water mist supply devices are respectively connected.

2# wei8jun Is this used in the chemical industry?

A new process developed by Fujian Lishu Pulp and Paper Co., Ltd. located in Jian’ou – the steam explosion pulping process – has brought significant economic and social benefits to the company. Traditional chemical pulping requires cooking with chemical agents for about 5 hours, and over 200 kg of coal is consumed per ton of finished pulp. Using the steam explosion pulping process, the product can be obtained from the tank in 1 hour, and less than 40 kg of coal is required per ton of finished pulp. Moreover, the pulp yield from chemical pulping of raw materials for paper production is only about 40%, whereas that of steam explosion pulping is as high as 75%. Lishu Pulp & Paper Company established itself in the Jianfan Xingning Industrial Park in 2004, with an investment of 60 million yuan. It mainly produces high-strength corrugated paper, kraft box boards, and environmentally friendly dry wood pulp, with an annual production capacity of 50,000 tons. The company uses a world-leading anhydrous, drug-free physical steam pulping process. It is reported that this process builds on a new technology for pulping corn stalks through steam explosion, developed by a related company of this firm. After hundreds of attempts by technical staff over the course of a year, and with an investment of over 8 million yuan, the technical transformation for pulping waste bamboo using steam explosion has been largely completed. The steam explosion pulping process does not involve the addition of any chemicals during the steam explosion stage; the pulp obtained is in solid form, and there is no issue with black liquor, thereby fundamentally solving the problem of treating papermaking wastewater. In traditional chemical pulping, the ratio of plant raw materials to water used is 1:4, and mechanical pulping also requires four times as much water ； In contrast, the ratio of plant raw materials to water used in steam pulping is less than 1:1, and its emissions amount to only 25% of those from chemical and mechanical pulping. Moreover, about 150 kg of chemical agents are required to process 1 ton of plant material in its absolutely dry state using chemical pulping, whereas steam blasting pulping requires almost no other chemical agents aside from adjusting the pH of the water during the processing stage; just this alone allows the company to save over 1,500 yuan per day

The process description for 5# is quite innovative; there are surely new applications as well.

During steam explosion, the plants (the materials to be exploded) are placed inside a pressure vessel. Based on the principle that the pressure is equal everywhere within a pressure vessel, high-pressure steam is introduced into the plant tissues through the tiny pores on their surface. Once the pressure inside the plant tissues reaches equilibrium with the pressure in the vessel, all the materials being exploded are suddenly exposed to atmospheric pressure. Due to the small size of the micropores on the surface of plants, if the external pressure drops rapidly to atmospheric pressure, only a small portion of the gas inside the plant can return to the atmosphere through these micropores. Instead, most of the high-pressure gas remaining inside the plant expands as a result of the pressure difference between the inside and outside, thereby damaging the internal structure of the plant tissue and leading to the partial separation of components such as lignin, cellulose, hemicellulose, and sugar chains.

I’ve been in contact with this steam explosion pulping method recently; it allows the plant structure to become loose and separate, and this can be achieved with sufficient pressure and temperature. It is widely used in pulp production. I was wondering if there are any autoclave devices used in the fiber industry on the 5th floor, devices that require precise control of temperature and pressure; otherwise, it can damage the fibers and affect the subsequent spinning process.