In December, the weather in Ping'an Town has begun to gradually warm, and a new factory in Jushu Township (formerly Jushu Village) in the north of Ping'an County (Ping'an Town) has begun to take shape. With the arrival of the Northern Gunpowder Factory and the newly planned No. 1 Chemical Plant, the rural northern area, which was originally dominated by agriculture and had only a small fruit canning factory, suddenly flooded with hundreds of permanent residents and an even larger number of South African construction workers.

After the population surged, Qian Hao, the magistrate of Ping'an County, simply applied to the Government Council to withdraw Jushu Village from the village and set it up as a township, which was approved a few days ago. After the successful establishment of Jushu Township, Ping'an County has included Ping'an Township, Coal River Township, Jushu Township, the town, two townships and three areas, while sitting firmly in the north's first important town, Ping'an County has begun to catch up with Dongfang County in the south in terms of population size and industrial and agricultural output value, and its weight in the eyes of the Executive Committee is becoming more and more sufficient.

At present, Song Qiang, director of the Institute of Chemistry of the Academy of Natural Sciences, is the director of the newly established No. 1 chemical plant in Jushu Township, and the main product produced by the plant at this stage is sulfuric acid. Yes, you read that right, after many days of delay and a series of pre-existing problems, the production of sulfuric acid, an extremely important chemical basic raw material, can finally enter the substantive operation stage.

Since last year, with the gradual deepening of the domestic industrialization process, all walks of life (such as papermaking, printing and dyeing, textile, etc.) have generated a lot of demand for sulfuric acid. To this end, several chemistry teachers from the Academy of Natural Sciences led a group of students to start an attempt at industrial production of sulfuric acid.

Although a large amount of concentrated sulfuric acid has been successfully prepared in the laboratory for a long time, industrial production and laboratory preparation are two completely different concepts. The first thing they started with was acid-resistant materials, namely acid-resistant bricks and acid-resistant cement. There has not been much progress in the research of acid-resistant cement. However, acid-resistant bricks have been successfully fired. The technicians of Henan Glass Factory and Building Materials Factory have been researched and trial-produced for more than half a year. A few months ago, a batch of acid-resistant bricks with a silica content of up to 70% was successfully fired. It has strong resistance to various inorganic strong acids and can be used in the industrial production of sulfuric acid.

The main equipment, production lines and workshops of the factory were all designed by Song Qiang. In order to show its importance, the Government Council instructed the Ministry of Communications to undertake the construction of the first bureau (currently a total of five bureaus) with the most abundant technical strength and experience, in order to ensure the quality of the construction and equipment installation of the entire plant.

Song Qiang himself has never been engaged in the sulfuric acid production industry, and his impression of the early sulfuric acid production method only exists in the article on the local method of producing sulfuric acid that he had seen in a certain magazine. However, this did not prevent him and several colleagues from working together to gradually restore the production steps of industrial sulfuric acid production through discussions and experiments.

The main production equipment of the first chemical plant is seven production towers, which are the first to fourth generation towers, the oxidation tower, and the first and second absorption towers, in addition to some sanitary towers, fog traps and other exhaust gas cleaning devices.

The raw materials for the production of sulfuric acid are sulfur and some laboratory prepared sulfuric acid containing nitrate. Elemental sulfur (also metal sulfides. Such as pyrite, etc.) is burned in the incinerator, and the furnace gas (of which sulfur dioxide accounts for about 7%) enters the bottom of the first generation tower after passing through the dust removal chamber, and meets the nitrate-containing sulfuric acid (containing nitrososulfuric acid HNSO5) sprinkled from the top. Nitroso sulfuric acid is hydrolyzed and denitrified under the action of high temperature of furnace gas to produce sulfuric acid (H2SO4) and many nitrogen oxides (nitrous oxide N2O3).

These nitrogen oxides are highly oxidizing and oxidize sulfur dioxide (SO2) to sulfur trioxide (SO3), which reacts with water to form sulfuric acid while emitting a large amount of heat.

In the oxidation process, a large amount of nitrogen oxide (NO) is produced again, and NO can react with oxygen to form nitrogen dioxide (NO2) again. It can be seen from this that nitrogen oxides such as nitric oxide and nitrogen dioxide actually only act as a catalyst, and at the same time they are consumed and constantly generate new ones. Can be recycled. In the process, sulfuric acid is also being generated.

The furnace gas from the first generation tower (about 40% of the sulfur dioxide is rejected) passes through the next three same sulfuric acid generation towers. Entering the oxidation tower, most of the sulfur dioxide has been reacted away, and the main component of the remaining gas is NO. NO is partially oxidized, and then enters the first and second absorption towers behind, and is absorbed by the sulfuric acid sprinkled on the top of the tower to form nitroso sulfuric acid, so as to realize the recycling of nitrogen oxides. The most exhaust fumes enter the chimney through the sanitary tower and fog trap and are emitted into the atmosphere.

The entire production process is cleverly designed to be recycled and reused. Among them, the sulfuric acid from the first generation tower has been denitrified, cooled and exported through the pipeline, partly as a finished product, and partly as the sprinkling acid of the two towers (the first and second absorption towers) in the back. The acid (containing nitro sulfuric acid) from the first and second absorption towers can be used as the acid spraying of the first towers (the first, second, third and fourth generating towers), and the oxidation tower does not carry out acid spraying because there is no filler, and the whole process realizes circular production.

In this production line, Song Qiang and others gave full play to their ingenuity, did not copy the 18th and 19th centuries in the history of the European lead chamber method, tower method to produce sulfuric acid routine, but according to the actual situation to make bold improvements, the overall technology has reached the level of the early 20th century. For example, the dust chamber is a design that did not exist in Europe, and the pipes that heat the furnace gas (to maintain the temperature of the furnace gas) are also not designed in the past.

The core equipment of the production line, the "tower", is made of acid-resistant brick powder fired in the kiln as a whole, in the shape of a cylindrical shape, and placed on the ground. There is a filler at the bottom, which is acid-resistant glass balls, quartz blocks, coke, etc., which is to increase the reaction area. At the top of the tower is a drenching basin for acid spraying, also made of acid-resistant material. At the bottom of the drenching basin are small holes to allow the drenching acid to leak into the column.

In the early production process of Europeans, they used to have workers carry a large vat full of acid to pour sulfuric acid into the drenching basin, and the acid could easily spill out in the process, causing accidents. In Song Qiang's design, he boldly adopted the siphon principle to design an automatic acid adding device.

That is, a large acid bottle filled with acid liquid with a pipe at the bottom leading to the acid basin is placed in the high place next to the acid bath, and another pipe hangs down at the top of the large acid bottle. When the sour worker comes with the acid bucket, he only needs to connect the pipe hanging down from the top of the acid bottle to the bottom of the acid liquid in the acid tank, and then open the pipe from the acid bottle to the acid drenching basin. After the acid in the acid bottle enters the showering basin, the acid level in the acid bottle drops, and the atmospheric pressure begins to press the acid in the acid bottle into the acid bottle, so that the acid level in the acid bottle always maintains a certain height, so as to realize automatic acid addition.

The design of the sanitation tower and fog trap is even more unique. In the early days, the sulphuric acid production workshops in Europe were a serious source of pollution, and were often forced to relocate due to protests from residents near the factories, mainly because the producers did not treat the exhaust gases (small amounts of sulphur dioxide, nitric oxide and acid mist) generated during the production process. In Song Qiang's design, the exhaust gas must first enter the sanitary tower before being discharged into the atmosphere, and concentrated sulfuric acid is placed in the sanitary tower, which can absorb the sulfur dioxide and nitric oxide in the exhaust gas; The remaining exhaust gas then enters a fog trap (an airtight container filled with coke) to absorb the acid mist, and the last gas is discharged into the atmosphere through the chimney. The chimney here should be made as high as possible to allow for exhaustion.

Before the sanitary tower, some people in the chemical institute proposed whether a steam exhaust fan could be installed to maintain negative pressure inside the first few towers, so that the gas could pass through each tower smoothly in order, and then enter the sanitary tower and discharge into the atmosphere after the fog catcher. Song Qiang thought about it and felt that this idea was still good, so he decisively followed the good and added this design.

The six cylindrical "towers" have a diameter of 1.2 meters and a height of 1 meter, and are expected to produce about 1 ton of finished sulfuric acid per day with a purity of about 70% or more. If the whole production process is well controlled, sulfuric acid with a purity of about 75% can be prepared. At that time, these sulfuric acids will also be steamed in the steaming and thickening workshop next door to produce concentrated sulfuric acid that can be used in industrial production.

The entire production process and process of sulfuric acid rely on the existing technology and industrial level, and take into account the economic benefits, that is, the expensive lead chamber method is abandoned (and the lead chamber method will produce a lot of impurities), and all the equipment is almost all made of red brick refractory bricks (incinerator), acid-resistant powder (reaction tower), glass (acid bottle), etc., which are incredibly low in cost.

With concentrated sulfuric acid, the chemical industry of the East Coast Republic of China can be regarded as truly opening up the situation. Since then, salt chemical industry (sodium chloride and concentrated sulfuric acid reaction to produce hydrochloric acid and sodium sulfate) can be gradually developed, and the feasibility of small-scale industrial production of nitric acid (potassium nitrate reaction with concentrated sulfuric acid) has gradually entered the eyes of a group of technicians in the Institute of Chemistry.

All in all, the smooth operation of the sulfuric acid production line of the first chemical plant has a far-reaching impact on the industrial development of the East Coast Republic of China, and it is self-evident that it will promote the country's industrial upgrading and industrial progress. After all, only the development and progress of heavy industry can represent the progress of a country's industrial level, and the basic chemical industry such as three acids and two alkalis is one of the fundamentals of heavy industry. (To be continued......)