An effective way to control China’s immense amount of industrial emissions has finally been found thanks to SWRDICI's technology for producing ethylene glycol out of recycled industrial emissions and waste gas. This has increased the amount of raw materials available for ethylene glycol production, and it avoids the need for more complex equipment and techniques used in coal gasification and cuts total costs by 30 percent.
The technology was given the OK by experts from the Sichuan provincial Science and Technology Bureau, in Chengdu, on December 1. They said that the technology is a combination of three elements -- pollution reduction, resource conservation, and lower cost. It already has the possibility of being industrialized and has good prospects for broader applications.
The experts went on to point to three innovative characteristics: First, the two core catalysts that have industrial applications -- a palladium carbonylation catalyst and a copper hydrogenation catalyst. The two catalysts passed a long-term-operation test of more than 6,000 hours, with a 100-percent conversion rate and 90-percent selectivity. Second is the expanded supply of raw materials from industrial emissions, such as coal bed methane, coke oven gas, yellow phosphoric tail gas, and calcium carbide furnace gas, bringing down production costs by more than 20 percent.
The third innovation involves five crucial techniques -- the diethyl oxalate process and purification of carbon monoxide; two-bed esterification reactor; carbon monoxide coupling with a steady-state cycle of the regenerative reaction; the hydrogenation reactor; and the refined polyester class glycol products. These result in an integrated technique of low power and material consumption. Five national patents have been applied for, with four having been authorized.
The experts figured that the cost of making ethylene glycol out of petroleum would be 7,500 yuan/t (with crude oil at $75/barrel), the cost for making it out of coal would be 5,000 yuan/t, while the cost from industrial waste gas (such as yellow phosphorus tail gas or calcium carbide furnace exhaust) would be just 4,000 yuan/t. And, the technology will cut methanol consumption by 0.16t and steam consumption by 2.5t for each ton of ethylene glycol produced, compared with the coal-based ethylene-glycol process.
From the cost angle, a 100,000-t/yr facility that combines carbon monoxide production from yellow phosphorus tail gas extraction and ethylene glycol production by oxalate would run around 800 million yuan. But, with annual sales figured at about 1 billion yuan, that means 400 million yuan in profits. Seen from the environmental angle, each 1 million tons of yellow phosphorus output can cut phosphide emissions by 3,750 t, sulfide emissions by 7,500 t, arsenide by 200 t, and fluoride by 1,250 t (assuming that a standard cubic meter of yellow phosphorus tail gas contains 1.5g of phosphorus, 3g of sulfide, 0.08g of arsenide and 0.5g of fluoride).
China currently has 12 glycol manufacturers, most of which use petro-ethylene as raw material. By the end of the year, China's total ethylene glycol production capacity will be 4.5mt/a, while annual consumption will reach 800m t/yr. If that 400 t gap can be closed using industrial emissions as raw material, more than $3 billion worth of imports will be saved, and at least 2m t/yr of ethylene consumption cut.