Thread Content
The heat recovery rate in traditional sulfuric acid production plants is around 70%, whereas the low-temperature heat recovery technology developed by Monomack Corporation of the United States (hereinafter referred to as Monomack) enables the recovery of over 93% of the heat energy. At the same time, the amount of circulating cooling water required can be reduced by about 65%. This not only results in significant energy savings but also reduces production costs. Not long ago, this “low-temperature heat recovery technology for large and medium-sized sulfuric acid production plants” was included in the **List of Key Energy-Saving Technologies for Promotion (First Batch)**. Development: Pioneering the industrialization of low-temperature heat recovery. Mengmoke Company is headquartered in St. Louis, Missouri, USA. It originated as Monsanto Environmental Chemicals and was primarily involved in the sulfuric acid production facilities as well as environmental protection activities that were part of Monsanto’s core business. Since the development of the contact process for sulfuric acid production, Mengmoke Company has consistently held a leading position in the field of sulfuric acid industry technology. With nearly a century of experience in the design, manufacturing, production, and management of sulfuric acid plants, it is able to provide comprehensive solutions for sulfuric acid manufacturers using various raw materials and processes. These solutions include technical licensing, process package design, engineering design, pollution control, complete sets of equipment, special alloy materials, catalysts, mist eliminators, as well as assistance with plant construction, commissioning, staff training, and technical support services. To date, Mengmoke Company has designed and built nearly a thousand sets of sulfuric acid production facilities and related equipment worldwide, with its operations spanning over 60 countries and regions. Based on years of experience in sulfur and sulfur-related industries, Mengmoke Company has developed an advanced technology with great market potential and significant energy-saving and emission-reduction benefits – the HRS technology. The process for producing sulfuric acid from sulfur mainly consists of three stages: the combustion of sulfur with air to produce sulfur dioxide, the conversion of sulfur dioxide into sulfur trioxide, and the absorption of water molecules by sulfur trioxide to form sulfuric acid. All three of the above steps are exothermic reactions. The heat released in the first and second stages accounts for about 75% of the total heat released; the heat generated in these two stages is referred to as high-temperature heat ； The heat released by the third section accounts for about 25% of the total heat released, and the heat generated in this section is known as low-temperature heat. Since the 1870s, how to make full use of the heat energy generated during the reactions in the sulfuric acid production process has been a focal point for the global sulfuric acid industry. In 1980, Mengmok Company was the first to introduce modern design theories for efficient energy utilization, which increased the production of high-pressure steam in the first two processing stages by over 20%, contributing to the recovery of heat energy at high temperatures. However, before the advent of HRS technology, sulfuric acid plants around the world could only recover the heat generated in the first two stages; in other words, the heat recovery rate was only around 70%. For the third unit, the traditional process involves using concentrated sulfuric acid to absorb sulfur trioxide. However, since the reaction is exothermic, the rise in temperature of the sulfuric acid leads to increased corrosion of the equipment; therefore, it is necessary to use circulating cooling water to keep the temperature of the sulfuric acid below 80°C. As a result, the waste heat can only be discharged directly into the atmosphere. This means that traditional processes not only waste thermal energy but also require a large amount of cooling water. Project, Unit, Traditional Process, HRS, HRS Strip, Steam Jet, High-Efficiency HRS, Remarks: High-pressure steam, tons per ton of acid – 1.27, 1.20, 1.19, 1.21; 6.2 MPa, 482°C. Medium-pressure steam, tons per ton of acid – 0, 0.44, 0.48, 0.46; 1.0 MPa, 250°C. Total steam generated, tons per ton of acid – 1.27, 1.64, 1.67, 1.67. Energy recovery rate, % – 70, 93, 93, 93. Net electrical energy produced, kilowatts/(ton/day) – 10.6, 14.6, 14.8, 15.1. Electricity consumed by the equipment itself, kilowatt-hours per ton of acid – 254, 350, 355, 362. However, Mengmoke Company has never given up on research and development efforts to recover this wasted thermal energy in traditional processes. They brought together top talents from fields such as chemical engineering, mechanical engineering, corrosion prevention engineering, and instrumentation engineering to conduct in-depth research, and finally developed in 1984 a technology for recovering the heat lost in the acid coolers of the third processing unit – namely the HRS technology. In 1987, the world’s first set of HRS units was installed and put into use in Norway, marking the beginning of Mengmok Company’s pioneering work in transitioning low-temperature heat recovery in sulfuric acid production from theoretical research to industrial application. Mengmoke Company has always adhered to the principle of providing users with high-quality technology, high-standard products, and excellent services. Through its relentless pursuit of HRS technology to almost obsessive levels, it is committed to maximizing the recovery and utilization of the heat generated in sulfuric acid reactions. Today, after more than two decades of development, HRS technology is capable of recovering over 93% of the thermal energy generated during the sulfuric acid production process. This not only improves the efficiency of thermal energy recovery but also reduces the amount of circulating cooling water used by about 65%, thereby **lowering production costs. The emergence and industrial application of HRS technology are regarded by the industry as a major transformation in the sulfuric acid production process. Currently, Mengmoke Company’s HRS technology is the only viable technology in the world for low-temperature sulfuric acid recovery. There are over forty HRS units built or under construction worldwide, and they are widely used in industries such as phosphate fertilizer production and metal smelting. Applications: Dual benefits in terms of environmental and economic outcomes. According to Patrick Ritschel, in recent years Mengmok has increased its efforts to promote this technology in Asia, particularly in the Chinese market. Just 3 years after it entered this market, through its subsidiary Mengmok Chemical Equipment (Shanghai) Co., Ltd., 10 HRS units have been built and put into operation in China. These units have received recognition from users, and they are being adopted by an increasing number of Chinese companies. To date, multiple patents have been filed for HRS technology. The payback period for this technology is approximately 2–3 years, and the economic benefits it brings to users are reflected in the following three aspects: first, it is possible to use the recovered heat energy to generate steam. Steam can be used directly or for cogeneration. A sulfuric acid production plant designed with an output of 3,000 tons per day can be equipped with a 50MW generator set, generating a considerable amount of electricity ； Secondly, it **reduces the amount of circulating cooling water used in the original absorption section, enabling the company to save substantial amounts of money and thereby lowering production costs** ； Thirdly, the HRS technology has been certified as a project under the United Nations Clean Development Mechanism (CDM); therefore, companies that adopt this technology can apply to participate in international carbon reduction trading, thereby receiving direct financial support for the technology and reducing the investment payback period. As global capital and industries flow in large numbers to Asia, particularly China, the country faces increasing pressures related to energy shortages and environmental protection. Both new projects and upgrades to existing ones are required to meet higher standards for energy conservation and emission reduction. Therefore, the HRS technology developed by Mengmok Company has undoubtedly become one of the best solutions to this challenge in the sulfuric acid production process. In April 2005, China’s first HRS unit – the 1 million tons per year sulfur-based sulfuric acid production plant at Shuangshi Zhangjiagang Fine Chemicals Co., Ltd. – was successfully put into operation. It employed the most advanced HRS technology available at that time, which included steam injection. More than three years of operation have shown that this unit runs smoothly, with a total downtime of less than 12 hours, thus setting a new record for continuous operation of sulfuric acid production plants in China. Shuangshi Chemical also utilizes the steam generated by the HRS system for cogeneration, reducing energy waste and saving a significant amount of money. In August 2006, the HRS sulfur-based acid production plant of Hubei Yihua Group was also brought online successfully. To date, the economic benefits of this HRS sulfur-based acid production plant at Hubei Yihua have already become apparent; low-temperature heat recovery not only **reduces heat loss and increases steam production, but it also lowers water consumption. In March this year, the project also received CDM project certification from the United Nations, marking the first time that a sulfuric acid plant in China has obtained such certification. By participating in carbon emission reduction transactions in the international market, Hubei Yihua Group has directly earned millions of dollars in benefits from reduced emissions, achieving both environmental and economic advantages. Due to the excellent performance of the HRS unit and its significant economic returns, Shuangshi Chemical and Hubei Yihua decided to install a second HRS unit each; both units were put into operation in 2008 and 2009 respectively. In light of the fact that most sulfuric acid production facilities in the Chinese market are small to medium-sized units with a capacity of less than 300,000 tons per year, Yumoke Company has specifically developed processes that allow two or even more sulfuric acid production units to share one HRS unit, and such systems have already been put into use at companies such as Yuntianhua and Sinochem Chongqing Fuling Chemical. Development: Continuous improvement never stops. As a specialized technology company with nearly a century of experience in sulfuric acid production, Mengmoke has used HRS technology to transform sulfuric acid production facilities into green energy plants that do not generate greenhouse gas emissions, while also enabling maximum recovery and utilization of heat energy. With this technical support, the sulfuric acid plant first functions as a power plant or steam supply unit, and only secondly as a sulfuric acid production facility. Since the emergence of HRS technology in 1984, Mengmoke Company has continued to refine and improve it. Through comprehensive planning of the entire HRS system, it has gradually determined the most suitable reaction temperatures and concentrations, the best equipment components, the most corrosion-resistant materials, as well as the most efficient methods for real-time monitoring of reaction parameters. On this basis, the company has managed to upgrade HRS technology. Over the years, Mengmok Company has made improvements to both the recovery tower and the tower acid separator, enhancing the operational stability of the recovery tower and improving the absorption efficiency of SO3 ； Later, they improved the instrumentation and control systems, further enhancing the stability of the system’s operation ； HRS technology with steam injection was also developed, reducing the overall size of the equipment and lowering costs. In the field of sulfuric acid production, Mengmoke Company has developed a range of specialized technologies and equipment. From dedicated mist removers such as the Brink mist remover, to power wave gas scrubbers that are widely used in the production of acid from smelting flue gases, as well as the SAR (Spent Acid Regeneration) technology for recycling waste sulfuric acid, all these reflect Mengmoke Company’s persistent commitment to green environmental protection and energy-saving technologies. Currently, Mengmoke Company is making changes to the acid separators and related equipment in order to further improve steam recovery rates, reduce investment costs, and better meet market demands. Patrick Ritschel also happily told reporters that MONARCH technology, newly developed by Mengmok Company, is already capable of raising the steam recovery rate in the sulfuric acid production process to 100%, and it is set to be put into industrial use soon. Amid the backdrop of rising energy prices, HRS technology enhances the overall energy recovery rate from 70% in conventional systems to over 93% by maximizing the recovery and utilization of energy in the sulfuric acid production process. It also reduces the consumption of circulating cooling water; this technology is of great value both for individual enterprises and for the entire sulfuric acid industry. In an era when the world is paying attention to the greenhouse effect, HRS technology has become one of the 25 types of greenhouse gas reduction measures that are given priority under the Clean Development Mechanism (CDM). It serves as a bridge that enables enterprises to participate in international carbon reduction market transactions, obtain support in the form of international funds and technology, and carry out industrial upgrades. With the rapid development of China’s economy, Mengmoke Company has established branches in **, Shanghai, and Kunming. Mengmoke’s goal in China is to continuously improve technology, enhance efficiency, and reduce costs in order to meet the demands of localization and domestic production in China.